1. Exposure Data

1.1. Identification of the agent

1.1.1. Nomenclature

• Chem. Abstr. Serv. Reg. No.: 127-18-4
• Chem. Abstr. Name: Tetrachloroethene
• IUPAC Systematic Name: Tetrachloroethylene
• Synonyms: Ethylene tetrachloride; PCE; ‘per’; PER; PERC; perchlorethylene; perchloroethene; perchloroethylene; tetrachlorethylene; 1,1,2,2-tetrachloroethene; 1,1,2,2-tetrachloroethylene

1.1.2. Structural and molecular formulae and relative molecular mass

• C₂Cl₄
• Relative molecular mass: 165.83

1.1.3. Chemical and physical properties of the pure substance

• Description: Colourless, nonflammable liquid; ethereal odour (O’Neil et al., 2006)
• Boiling-point: 121 °C (O’Neil et al., 2006)
• Melting-point: −22 °C (O’Neil et al., 2006)
• Density: 1.6230 at 20 °C/relative to H₂O at 4 °C (O’Neil et al., 2006)
• Spectroscopy data: Infrared (prism [5422]; grating [469]), ultraviolet [1485] and mass [1053] spectral data have been reported (Sadtler Research Laboratories, 1980; Weast & Astle, 1985).
• Solubility: Slightly soluble (0.206 g/L at 25 °C; HSDB, 2012); miscible with alcohol, ether, chloroform, benzene (O’Neil et al., 2006); soluble in ethanol, diethyl ether and benzene (Haynes, 2012)
• Volatility: Vapour pressure, 1 kPa at 10 °C (Haynes, 2012)
• Stability: Photo-oxidized in air with sunlight (half-time, about 12 hours), giving phosgene and trichloroacetyl chloride (EPA, 1982; Hickman, 1993)
• Reactivity: Incompatible with chemically active metals such as barium, lithium and beryllium, and with sodium hydroxide, potash and strong oxidizers (NIOSH, 1994)
• Octanol/water partition coefficient (P): log P, 3.40 (Hansch et al., 1995)
• Conversion factor: mg/m³ = 6.78 × ppm, calculated from: mg/m³ = (relative molecular mass/24.45) × ppm, assuming normal temperature (25 °C) and pressure (101 kPa).

1.1.4. Technical products and impurities

Tetrachloroethylene is available commercially in several grades, including a vapour degreasing grade, a dry-cleaning grade, an industrial grade for use in formulations, a high-purity low-residue grade, a spectrophotometric grade, and a grade specifically formulated for use as a transformer fluid (IARC, 1995; ATSDR, 1997a). It typically has a purity of 95% or more for dry-cleaning and industrial grades, 99% or more for more refined grades, and 99.995% for isomerization and fluorocarbon grades. The various grades differ in the amount and type of stabilizers added to prevent decomposition (ATSDR, 1997a).

Trade names for tetrachloroethylene include Ankilostin, Antisol 1, Didakene, Dow-per, Dilatin PT, Fedal-Un, Nema, Perawin, Perchlor, Perclene, Percosolv, Perklone, PerSec, Tetlen, Tetracap, Tetraleno, Tetralex, Tetravec, Tetroguer and Tetropil (IARC, 1995; Doherty, 2000a; EPA, 2013).

1.1.5. Analysis

Several methods for the analysis of tetrachloroethylene in air, solids, liquids, water, and food were reviewed by WHO (1984), EPA (1985), Greenberg et al. (1992) and Demeestere et al. (2007). Selected methods for the analysis of tetrachloroethylene in various matrices are presented in Table 1.1.

Table 1.1

Methods for the analysis of tetrachloroethylene.

1.3. Occurrence and exposure

1.3.1. Natural occurrence

Tetrachloroethylene has been reported in temperate, subtropical and tropical algae, and in one red microalga (Abrahamsson et al., 1995).

1.3.2. Environmental occurrence

Tetrachloroethylene is a volatile organic compound that is widely distributed in the environment due to industrial emissions. Potential environmental exposure to tetrachloroethylene in air, rainwater, surface water, and drinking-water has been reviewed (ATSDR, 1997a). The partitioning tendency of tetrachloroethylene in the environment has been calculated as follows: air, 99.7%; water, 0.3%; soil, < 0.01%; sediment, < 0.01% (Boutonnet et al., 1998).

(a) Air

Measurement data from remote North American sites indicate that background concentrations of tetrachloroethylene have decreased since 1995 by more than 5% per year (McCarthy et al., 2006).

Table 1.2 presents some recent data on concentrations of tetrachloroethylene in air, measured worldwide in remote, rural, suburban, and urban sites, and in indoor air near dry-cleaning shops.

Table 1.2

Concentrations of tetrachloroethylene in air.

(b) Water

Tetrachloroethylene occurs at low concentrations in drinking-water supplies and frequently occurs as a contaminant of groundwater, owing to its widespread use and physical characteristics. Table 1.3 presents recent measurements of concentrations of tetrachloroethylene in surface waters, groundwater and drinking-water.

Table 1.3

Concentrations of tetrachloroethylene in water.

(c) Food

As a part of the Total Diet Study in the USA, 20 samples of 70 different foods purchased in supermarkets or restaurants were analysed for tetrachloroethylene during 1996–2000. Tetrachloroethylene was found at low concentrations (up to 102 µg/kg) in 29 out of 70 food items (Fleming-Jones & Smith, 2003).

In a survey of 35 samples of whole milk from Las Vegas, NV, USA, tetrachloroethylene was found at a mean concentration of 0.09 µg/L (range, < 0.01–0.39) (Hiatt & Pia, 2004).

The average concentration of tetrachloroethylene in 4 out of 17 samples of brown grease from food-preparation facility grease traps was 2771.1 µg/L (range, 31.5–8510 µg/L) (Ward, 2012).

1.3.3. Occupational exposure

The National Occupational Exposure Survey conducted between 1981 and 1983 by the United States National Institute for Occupational Safety and Health (NIOSH, 2013) estimated that about 688 000 workers in a wide range of industries, notably dry-cleaning, textiles, metals, automotive, printing and cleaning, were potentially exposed to tetrachloroethylene in the USA at that time. This estimate was based on a survey of products used in companies in 1981–1983 and did not involve actual measurements.

The European CAREX project estimated the number of exposed workers in 15 countries of the European Union (EU-15) to be approximately 820 000 in the early 1990s. Most exposures occurred in dry-cleaning shops (Kauppinen et al., 2000). An update of CAREX for Italy by Mirabelli & Kauppinen (2005) showed a negligible increase in the number of workers exposed, from 102 500 to 106 300, for 1990–1993 and 2001, respectively (excluding jobs flagged as low-level or low confidence).

The number of exposed individuals in Germany in the dry-cleaning industry only was estimated to total almost 25 700 in 1975, decreasing considerably to about 5900 in 2001. This was mainly due to a reduction in the number of garments being dry-cleaned and, to a lesser extent, the replacement of tetrachloroethylene by nonchlorinated solvents. Merging of smaller shops into larger facilities also decreased the number of dry-cleaning machines by 77% (von Grote et al., 2006).

Table 1.4 presents exposure to tetrachloroethylene in the dry-cleaning industry by country and time period. Gold et al. (2008) reported average personal exposures of 59 ppm for dry-cleaning workers in the USA in 1936–2001. Lynge et al. (2011) provided insight into temporal trends in exposure to tetrachloroethylene in Nordic countries over a 60-year period. In the mid-1970s, personal exposures were reported as a median concentration of about 20 ppm, and this decreased to about 3 ppm in 2000. Stationary measurements indicated concentrations up to 100 ppm in the 1950s and 1960s (see Fig. 1.1). Recent studies in Egypt and the Islamic Republic of Iran showed that high exposures in dry-cleaning still occur, with concentrations of 100 ppm in air reported in both countries (Azimi Pirsaraei et al., 2009; Emara et al., 2010; Rastkari et al., 2011).

Table 1.4

Exposures to tetrachloroethylene in dry-cleaning shops.

Fig. 1.1

Air concentrations of tetrachloroethylene in dry-cleaning shops in the Nordic countries

Exposure to tetrachloroethylene in other industries and occupations (mainly degreasing, particularly in the metal and plastics industries) is summarized in Table 1.5, presented by industry and country. Gold et al. (2008) reported average concentrations for personally measured exposure among workers degreasing metal and plastics in the USA to be 95 ppm during 1944–2001. In these industries, exposure levels have decreased by two orders of magnitude over a 60-year period.

Table 1.5

Exposures to tetrachloroethylene in industries and occupations other than those associated with dry-cleaning.

Concentrations of tetrachloroethylene in blood among workers in dry-cleaning and other industries are summarized in Table 1.6. For studies on biological monitoring of urine for trichloroacetic acid, a metabolite of tetrachloroethylene, the reader is referred to the Monograph on trichloroacetic acid in this Volume.

Table 1.6

Biomonitoring of occupational exposure to tetrachloroethylene.

1.3.4. Exposure of the general population

Exposure to tetrachloroethylene has been measured in several populations not exposed occupationally, primarily in Germany and the USA (Table 1.7). While concentrations are generally low, living near a dry-cleaning facility considerably increases the level of exposure (Altmann et al., 1995; Schreiber et al., 2002; Storm et al., 2011).

Table 1.7

Population exposures to tetrachlorethylene.

In a study of breast milk in the USA, tetrachloroethylene was detected in seven out of eight samples analysed (Pellizzari et al., 1982).

1.4. Regulations and guidelines

Tetrachloroethylene has been registered on the Regulation on Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) of the European Commission (ECHA, 2013). Allowable time-weighted averages range from 70 mg/m³ in Denmark and Sweden, to 345 mg/m³ in some other European countries (Table 1.8). The European Union recommendation for an occupational exposure limit (OEL) according to the Scientific Committee on Occupational Exposure Limits (SCOEL) is 20 ppm for workers (European Commission, 2009). The American Conference of Governmental Industrial Hygienists (ACGIH, 2002) has established a threshold limit value (TLV) of 25 ppm and biological exposure indices (BEIs) of 5 ppm in end-exhaled air collected before the last shift of the working week, 0.5 mg/L in blood collected before the last shift of the working week, and 3.5 mg/L as trichloroacetic acid in urine collected at the end of the working week.

Table 1.8

Regulations and guidelines for tetrachlorethylene.

The state of California, USA, has started to phase out the use of tetrachloroethylene for dry-cleaning, and any new uses have been banned as from 2008, while use in pre-existing machines is to be discontinued by 2023 (California EPA, 2008). No information on bans in any other countries was available to the Working Group.

2. Cancer in Humans

In the previous evaluation by the IARC Monographs IARC (1995), the Working Group concluded that tetrachloroethylene was probably carcinogenic to humans (Group 2A) based on limited evidence in humans and sufficient evidence in experimental animals. In studies in humans, associations occurred with cancers of the oesophagus, cervix, and with non-Hodgkin lymphoma, but confounding could not be entirely excluded. No consistent pattern of elevated risk was observed for cancer of the kidney.

A substantial body of literature on the epidemiology of cancer and exposure to tetrachloroethylene was available to the Working Group and included both cohort and case–control studies. The two designs complement each other in that cohort designs typically provide a narrower range of occupations for exposure assessment than do case–control designs, while case–control studies are able to control for some important potential confounders. While many cancers have been evaluated, there has been a focus on lymphatic and haematopoietic cancers, and tumours of the urinary tract. Exposure assessments range from simple job-title determinations to quantitative assessments. While tetrachloroethylene has been used in several occupations, including vehicle repair, other mechanics, printers, and electricians, it is particularly associated with dry-cleaning (see Section 1). In many workplaces where tetrachloroethylene is used, other chlorinated solvents can also be found. There is some overlap between exposures to tetrachloroethylene and trichloroethylene in studies evaluated for this Monograph; this complicated the interpretation of study findings, but it should be remembered that nearly all workplaces have multiple exposures.

The Working Group did not consider in its evaluation several studies that reported results only for “laundry and dry-cleaning workers” combined (Malker & Weiner, 1984; McLaughlin et al., 1987; Lynge & Thygesen, 1990; Minder & Beer-Porizek, 1992; Lynge et al., 1995; Andersen et al., 1999; Travier et al., 2002; Pukkala et al., 2009). Similarly, studies based on occupations coded on death certificates that combined laundry and dry-cleaning workers (Katz & Jowett, 1981; Duh & Asal, 1984; Nakamura, 1985; Walker et al., 1997) were also considered to be uninformative with regard to tetrachloroethylene exposure. Launderers typically handle soap and other chemical cleaning agents, while persons engaged in dry-cleaning work have used different types of chlorinated solvents, mainly tetrachloroethylene, supplemented with trichloroethylene and fluorocarbons (Andersen et al., 1999). Since the exposure assessment was not specific to tetrachloroethylene, this would consequently result in a dilution of the magnitude of any observed effect.

2.1. Cohort studies

Most of the studies of cohorts exposed to tetrachloroethylene focused on dry-cleaning and related occupations. However, a few cohorts of non-dry-cleaning workers are discussed in Section 2.1.2. In addition to studies that characterized exposure by employment in occupation or industry categories combining “laundry and dry-cleaning,” the Working Group also excluded studies of exposure to mixed solvents without further distinction.

2.1.1. Dry-cleaning workers

Tetrachloroethylene became the most commonly used dry-cleaning solvent in the 1950s, replacing carbon tetrachloride, which was considered to be more toxic, and trichloroethylene, which was harsher on fabrics (Ludwig, 1981; IARC, 1995; Doherty, 2000a, b). Large studies of cohorts of dry-cleaning workers have been conducted in Europe and the USA. Because of the large number of small shops with a few employees each and the high turnover in this industry, the United States National Cancer Institute (NCI) cohort was assembled through union records (Blair et al., 1979; Blair et al., 1990, 2003), as was the NIOSH cohort (Brown & Kaplan, 1987; Ruder et al., 1994, 2001; Calvert et al., 2011), while most of the European studies, with the exception of Anttila et al. (1995a, b), Lynge et al. (2006) and Seldén & Ahlborg (2011), used census records linked to cancer-registry or mortality data. None of the cohort studies of dry-cleaning workers assessed exposure to tetrachloroethylene directly. Table 2.1 presents the most recent results of cohort studies on eight cancer sites of interest: cancers of the lung, kidney, bladder, liver, breast, cervix, oesophagus, and lympohaematopoietic system (Hodgkin disease, non-Hodgkin lymphoma, multiple myeloma, and leukaemia).

Table 2.1

Cohort studies of occupational exposure to tetrachloroethylene.

The NCI cohort study enrolled members of a union of dry-cleaning workers in Missouri, USA, which had 11 062 members between 1945 and 1978, of whom 5790 had held membership for 1 year or more. After exclusion of 425 members for whom information on race, sex, or date of birth was unavailable, the analysis was restricted to 5365 members who were followed from entry to the union or on 1 January 1948 (whichever came later) until 1 January 1979: follow-up was extended to 31 December 1993 for the most recent update and included 5369 members (Blair et al., 2003). The cohort provided 146 082 years of follow-up until 1993 and expected numbers of deaths were calculated from national rates. The mortality rate was as expected for all causes combined (standardized mortality rate [SMR], 1.0; 95% CI, 1.0–1.1; 2351 deaths), but slightly higher than expected for cancer (SMR, 1.2; 95% CI, 1.1–1.3; 590 deaths). Excesses were found for cancers of the oesophagus (SMR, 2.2; 95% CI, 1.5–3.3; 26 deaths), lung (SMR, 1.4; 95% CI, 1.1–1.6; 125 deaths), cervix uteri (SMR, 1.6; 95% CI, 1.0–2.3; 27 deaths) and bladder (SMR, 1.3; 95% CI, 0.7–2.4; 12 deaths), and for Hodgkin disease (SMR, 2.0; 95% CI, 0.6–4.6; five deaths). There was no excess of cancer of the liver or of the kidney (see Table 2.1). The risk of cancer of the oesophagus was highest for African-American men (SMR, 3.1; 95% CI, 1.9–5.0; 18 deaths). Exposure assessment was based on the published literature, applied to the job titles in the union records. The relative risk for cancer of the oesophagus for all cohort members was not related to the estimated exposure level; for those with little or no exposure it was 2.1; for those with medium or high exposure it was 2.2. There were 18 deaths from lymphatic and haematopoietic malignancies among those with little or no exposure (SMR, 1.0) and 17 (SMR, 0.9) among those with medium or high exposure. When mortality was compared by year of joining the union (before or after 1960, when tetrachloroethylene became the predominant solvent used), there was no difference at most sites except bladder, for which the SMR for those joining the union before 1960 was 1.1 (95% CI, 0.5–2.0, nine deaths), and for those joining after 1960 the SMR was 2.9 (95% CI, 0.6–9.5, three deaths). [The size of the cohort and the extended follow-up made this a valuable study. There was little evidence of an exposure–response effect, but the Working Group noted that the higher mortality for cancer of the bladder after the introduction of tetrachloroethylene supported the involvement of an occupational rather than a lifestyle risk factor. The Working Group also noted, however, that mortality from cancer of the oesophagus was in excess, possibly supporting an effect of smoking.]

The NIOSH cohort included 1704 unionized dry-cleaning workers from four cities in California, Illinois, Michigan and New York, USA. The inclusion criteria were: employment for at least 1 year before 1960 in a shop where tetrachloroethylene was the primary solvent used, and no known exposure to carbon tetrachloride. A survey in 1977–79 (Brown & Kaplan, 1987) showed geometric mean, time-weighted average concentrations of tetrachloroethylene in the range of 3–22 ppm (20.3–149 mg/m³); other solvents used for spot cleaning were not detected in the samples. Visits were made to many of the facilities that were still operating, and data on solvent use and solvent levels were collected (Ludwig, 1981). These monitoring data, and the job-title information available for about one third of the NIOSH cohort, were not used to create a job-exposure matrix for the NIOSH study, but were used to verify exposure to tetrachloroethylene and other solvents used in dry-cleaning, and to exclude workers who had been exposed to carbon tetrachloride or trichloroethylene.

In the analyses, two subcohorts were defined: people employed only in shops where tetrachloroethylene was the primary solvent used, and people whose work also involved exposure to other solvents. The most recent update added mortality follow-up until 31 December 2004, accounted for 94% of the women and 97% of the men, and generated 63 426 person-years at risk, but did not extend employment follow-up (Calvert et al., 2011). The mean duration of employment in dry-cleaning shops until 31 December 1990 was 6.4 years for those exposed only to tetrachloroethylene and 11.4 years for those also exposed to other solvents; the latter group had a mean duration of 6.0 years of exposure to tetrachloroethylene. Expected numbers of deaths were calculated from the national death rates. There were 1255 deaths (SMR, 1.0; 95% CI, 1.0–1.1) and 322 cancer deaths (SMR, 1.2; 95% CI, 1.1–1.4). The SMRs were significantly increased for cancers of the oesophagus (SMR, 2.4; 95% CI, 1.4–4.0; 16 deaths), tongue (SMR, 4.5; 95% CI, 1.5–10; five deaths), and trachea, bronchus and lung (SMR, 1.3; 95% CI, 1.0–1.6; 77 deaths). Mortality from cancer of the pancreas was elevated (SMR, 1.5; 95% CI, 1.0–2.3; 22 deaths). When the analysis was restricted to workers with a 20-year latency since first employment and with a duration of employment > 5 years, the SMRs were increased for cancers at all sites combined (SMR, 1.3; 95% CI, 1.2–1.5; 130 deaths) and, notably, for cancers of the oesophagus (SMR, 4.8; 95% CI, 2.7–8; 11 deaths) and urinary bladder (SMR, 4.1; 95% CI, 2.1–7; nine deaths). There were also three cancers of the tongue (SMR, 3.5; 95% CI, 0.73–10). Only one death from cancer of the liver and biliary tract was found (with 7.7 expected). The SMR for chronic obstructive pulmonary disease was 1.2 (95% CI, 0.8–1.6; 33 deaths). [In this study, exposure to tetrachloroethylene and other solvents was verified (until the end of work-history collection in 1978). The elevated SMRs for all cancers and oesophageal and bladder cancers for those who had worked 5 years or more support an exposure–response effect. However, because two thirds of the workers were exposed to solvents other than tetrachloroethylene, and there were no deaths from cancer of the bladder among workers exposed to tetrachloroethylene only, the possible contribution of exposure to other solvents must be considered. In addition, the cancer sites with excess mortality are all known to be associated with consumption of tobacco, and the elevated SMR for chronic obstructive pulmonary disease indicated that consumption of tobacco could play a role in the excess mortality at these sites. The excesses for cancers of the bladder and oesophagus, however, appear to be accounted for entirely by consumption of tobacco, given the relatively small increase in mortality from cancer of the lung.]

In a case–control study nested within the Nordic population (Lynge et al., 2006), the authors evaluated incident cases of selected cancers (bladder, oesophagus, gastric cardia, pancreas, cervix, kidney, liver, and non-Hodgkin lymphoma) reported in the respective national registers from 1997 to 2001. Three controls for each case (six for esophageal cancer) were randomly selected from the cohort and were frequency-matched by country, sex, 5-year age group, and date of case diagnosis by 5-year calendar period. The cohort focused on 46 768 laundry and dry-cleaning workers registered in the 1970 census in Denmark, Finland, Norway, and Sweden, because tetrachloroethylene was by far the most commonly used dry-cleaning solvent in these countries before and during the study period. Dry-cleaning workers were defined as “persons stated to be dry-cleaners, owners of dry-cleaning shops, and other persons employed in dry-cleaning shops with < 10 workers.” The last category was included because of the shared work tasks and physical proximity to equipment in small shops. Census and registry data were supplemented with implied exposure status (working as a dry-cleaner or in a dry-cleaning shop), based on original texts from the census forms (Denmark and Norway), interviews (Norway and Sweden), and pension-scheme data (Denmark and Finland) for cases and controls.

There was a statistically significant excess incidence of cancer of the bladder among dry-cleaners (relative risk [RR], 1.4; 95% CI, 1.1–1.9; 93 cases) and the risk of pancreatic cancer was also elevated (RR, 1.27; 95% CI, 0.90–1.80; 57 cases). There were no statistically significant excesses of cancer at any of the other sites. For those working in dry-cleaning for 10 years or more, there were elevated risks of cancers of the bladder (RR, 1.6; 95% CI, 1.1–2.3; 53 cases), pancreas (RR, 1.2; 95% CI, 0.7–2.0; 23 cases) and cervix (RR, 1.2; 95% CI, 0.6–2.2; 16 cases) and no increases in risk of cancer of the oesophagus, gastric cardia, kidney, liver, or of non-Hodgkin lymphoma (Lynge et al., 2006). [Tests for trend by increasing duration of employment were not presented.] [Table 2.1 presents results for those definitely known to be dry-cleaners only. The unexposed comparison group comprised laundry workers, rather than the general population used for comparison in cohorts from studies in the USA, to indirectly adjust for tobacco smoking habits.]

Seldén & Ahlborg (2011) assembled a cohort of 10 389 dry-cleaning and laundry workers in Sweden in 1984, based on a questionnaire mailed to all “washing establishments” (response rate, 38%) about workers, production volume, and chemicals used. Data on cancer incidence were obtained by matching to the national cancer register for 1985–2006. Use of tetrachloroethylene in dry-cleaning was reported by 61% of the cohort members (6356 out of 10 389). Among those who were exposed to tetrachloroethylene through dry-cleaning work, there was an increase in incidence of cancer among men only (standardized incidence ratio [SIR], 1.11; 95% CI, 0.97–1.26), with excesses of non-Hodgkin lymphoma (SIR, 2.0; 95% CI, 1.1–3.3; 15 cases) and cancers of the liver (SIR, 2.1; 95% CI, 0.9–4.2; eight cases) and lung (SIR, 1.3; 95% CI, 0.8–1.9; 23 cases). There was no significant excess of cancer of the bladder. [The study population may overlap with that of Lynge et al. (2006). Despite the large number of study participants and the identification of those exposed to tetrachloroethylene, the lack of quantitative data on exposure and the low response rate for the questionnaire were limitations of this study.]

A cohort of 3974 workers in Finland who were biomonitored for occupational exposure to halogenated hydrocarbons, including tetrachloroethylene, during 1974–1983 was followed for cancer incidence from 1967 to 1992 (Anttila et al., 1995a, b). These workers were exposed to tetrachloroethylene in dry-cleaning, and to a small extent also in degreasing and in the graphics industry. Among workers exposed to tetrachloroethylene, there was no overall increased risk of cancer (SIR, 0.9; 95% CI, 0.6–1.3; 31 cases), but there were indications of an increased risk of non-Hodgkin lymphoma (SIR, 3.8; 95% CI, 0.8–11.0; three cases) and cancers of the pancreas (SIR, 3.1; 95% CI, 0.6–9.0; three cases), cervix (SIR, 3.2; 95% CI, 0.4–12.0; two cases), and lung (SIR, 1.92; 95% CI, 0.62–4.48; five cases) [based on a small number of cases].

2.1.2. Workers in other industries

Bond et al. (1990) conducted a case–control study that was nested within a cohort of workers in a chemical plant in Michigan, USA (see Section 2.2.7). The risk estimate for cancer of the liver and biliary tracts associated with exposure to tetrachloroethylene, assessed via company work records, was 1.8 (95% CI, 0.8–4.3).

Boice et al. (1999) studied aircraft-manufacturing workers exposed to tetrachloroethylene and trichloroethylene in or after 1960 and followed for vital status until 1996. Exposure was assessed by industrial hygiene walk-through inspections of factories to become familiar with the manufacturing processes and patterns of use of chemicals; interviews with over 50 long-term employees (retired and active); review of existing industrial hygiene files, job descriptions going back to the 1940s, and other historical documents; and detailed job histories from the work history cards of factory workers. In 2681 workers exposed to tetrachloroethylene, overall cancer mortality was not elevated (SMR, 0.90; 95% CI, 0.82–0.98; 476 exposed cases), and for those workers with > 5 years of exposure, the relative risk was 0.74 (95% CI, 0.6–0.9; 123 deaths; P for trend, 0.01) compared with no exposure. For non-Hodgkin lymphoma, exposure was associated with increased risk without exposure–response relationship; for workers with > 5 years exposure, the relative risk was 1.4 (95% CI, 0.7–3.0; 10 deaths; P for trend, > 0.20) compared with no exposure. [Workers were exposed to multiple solvents so any increased risks may not have been attributable to tetrachloroethylene.]

A study of mortality in aircraft-maintenance workers (Radican et al., 2008) is discussed in more detail in the Monograph on trichloroethylene in this volume, because tetrachloroethylene was not the major or only solvent exposure. The following cancer outcomes were assessed in relation to exposure to tetrachloroethylene: cancer of the breast (one exposed case), non-Hodgkin lymphoma (hazard ratio [HR] in men, 2.3, 95% CI, 0.8–7.2, five exposed cases; HR in women, 2.4; 95% CI, 0.5–10.7; two exposed cases), and multiple myeloma (HR in men, 1.7, 95% CI, 0.4–6.9; three exposed cases; HR in women, 7.8; 95% CI, 1.4–43.1; two exposed cases), accounting for age, race, and sex.

2.2. Case–control studies

The association between occupational exposure to tetrachloroethylene and various cancers has been evaluated in numerous case–control studies. While a few studies assessed tetrachloroethylene specifically, the majority of studies assessed occupations and industries with potential exposure to tetrachloroethylene, such as dry-cleaning and aircraft workers. As discussed in Section 2.1, studies that assessed exposure to mixed solvents without distinguishing further, or that assessed the combined occupational category of “laundry and dry-cleaning workers” were excluded from this review (i.e. United States National Bladder Cancer Study by Silverman et al., 1989, 1990). No study further subdivided exposures by job tasks that would likely incur higher exposure (i.e. among dry-cleaning workers, no distinction was made between machine operators, who handle tetrachloroethylene-soaked garments, and other workers). One research group assessed the risk for several cancers associated with environmental exposure to tetrachloroethylene (Aschengrau et al., 1993, 1998, 2003; Vieira et al., 2005; Gallagher et al., 2011; Paulu et al., 1999).

2.2.1. Cancer of the bladder

The results of case–control studies of cancer of the bladder are presented in Table 2.2. All these studies adjusted for smoking.

Table 2.2

Case-control studies of cancer of the bladder and exposure to tetrachloroethylene.

The only study to report risk of cancer associated with residential exposure to tetrachloroethylene in drinking-water was carried out in Massachusetts, USA (Aschengrau et al., 1993). Living and deceased cases diagnosed in 1983–1986 were identified from the state cancer registry. Population controls from the same geographical area and matched by vital status and age group were selected by random-digit dialling, death registrations, or health insurance rolls, if aged > 65 years. Information about occupational history, water consumption, bathing habits, exposure to specific chemicals, and potential confounding factors was obtained by telephone or in-person interviews with subjects or their next of kin. Semiquantitative estimates of exposures to tetrachloroethylene were developed using an algorithm based on residence and water-system design. Multivariable logistic regression models were adjusted for sex, age at diagnosis or index year, vital status at interview, educational level, and occupational exposure to benzene and other solvents. The analysis included 61 cases of cancer of the bladder and 852 controls. The adjusted odds ratio was 1.39 (95% CI, 0.67–2.91) for any exposure to tetrachloroethylene, and 4.03 (95% CI, 0.65–25.10) for exposure above the 90th percentile of the semiquantitative estimates. The number of exposed cases was too small to allow analysis to account for latency. [This study included estimates of specific exposure to tetracholorethylene, and adjustment for an array of risk factors. However, interpretation was hampered by the small number of exposed cases.]

The NCI conducted the National Bladder Cancer Study, a case–control study of 2982 incident cases and 5782 controls carried out over 18 months, starting in 1977, in 10 areas of the USA (Hartge et al., 1984). As part of this study, Schoenberg et al. (1984) studied risk of cancer of the bladder according to occupation in white men in New Jersey, USA. Information on incident cases and age-stratified population controls selected by random-digit dialling was collected by interviewing in person to collect information about smoking, occupational history and exposures. The analysis included 658 cases and 1258 controls. The adjusted odds ratio for dry-cleaning workers was 1.33 (95% CI, 0.50–3.58; seven cases). [It is likely that all the analyses of the National Bladder Cancer Study used the same strategies for exposure assessment, and therefore the “dry-cleaning workers” group may have included launderers.].

In a study of men with urothelial cancer diagnosed in Stockholm, Sweden, in 1985–7, which included 254 cases and 287 referents, there was no increase in risk of urothelial cancer among men who reported working in dry-cleaning (RR, 1.2; 95% CI, 0.2–9.2; two cases) (Steineck et al., 1990).

A case-referent study of cancer of the bladder in Detroit, Michigan, USA, included 2160 cases of cancer of the bladder that were compared with 3979 cases of colorectal cancer identified from a surveillance programme (Burns & Swanson, 1991). The odds ratio for dry-cleaning workers, adjusted for smoking, race, sex, and age, was 1.9 (95% CI, 0.7–4.9; eight cases). Using the same source of data, cases of cancer of the bladder in women diagnosed in 1984–91 were compared with 1972 population controls for “usual occupation” and “ever employed” (Swanson & Burns, 1995). Having a “usual occupation” of dry-cleaning worker was associated with an adjusted (for age, race, and smoking) odds ratio of 2.0 (95% CI, 0.7–6.2; six cases). [The Working Group noted that there may have been some overlap between the cases included in these two studies].

Pesch and colleagues (Pesch et al., 2000a) carried out a study of urothelial carcinoma (bladder, ureter, and renal pelvis) in which exposure to tetrachloroethylene was evaluated using exposure matrices for job title or job task. Analyses with a job-exposure matrix reported relative risks for medium (men: 1.1, 95% CI, 0.9–1.3; women: 1.8, 95% CI, 1.0–3.0), high (men: 1.2, 95% CI, 1.0–1.5; women: 1.0, 95% CI, 0.6–1.9), and substantial (men: 1.4, 95% CI, 1.0–1.9; women: 0.7, 95% CI, 0.2–2.5) exposure. Analyses with a job-task exposure matrix reported relative risks for medium (1.0, 95% CI, 0.7–1.5), high (1.2, 95% CI, 0.8–1.7), and substantial exposure (1.8, 95% CI, 1.1–3.1), for men only.

Risk factors for cancer of the bladder in seven provinces of Canada were examined for 887 cases (535 men) diagnosed in 1994–97 compared with 2847 frequency-matched controls (1430 men) surveyed in 1996 (Gaertner et al., 2004). Among men, the odds ratio for employment as a dry-cleaning worker was 1.24 (95% CI, 0.23–6.64; four cases), adjusted for age, province, race, smoking, and nutritional factors. Data were not reported for women.

A study of cancer of the bladder in Maine, New Hampshire, and Vermont, USA, compared the occupations of 1158 people with cancer of the bladder newly diagnosed in 2001–4 and 1402 population controls. The odds ratio for workers in dry-cleaning plants was 0.86 (95% CI, 0.19–3.81; four cases) for men and 2.19 (95% CI, 0.41–11.85; six cases) for women after adjusting for several covariates, including smoking and occupation with a high risk of bladder cancer (Colt et al., 2011).

Christensen et al. (2013) conducted a study of occupational risk factors for selected cancers in men aged 35–70 years in metropolitan Montreal, Canada. In an analysis of 484 cases of cancer of the bladder and 533 population controls, odds ratios were 0.5 (95% CI, 0.1–3.0; two cases) for any exposure to tetrachloroethylene, and 0.9 (95% CI, 0.1–7.3; two cases) for substantial exposure to tetrachloroethylene, after adjusting for smoking and other covariates (Christensen et al., 2013).

2.2.2. Cancer of the upper aerodigestive tract

See Table 2.3.

Table 2.3

Case–control studies of cancers of the upper aerodigestive tract and exposure to tetrachloroethylene.

Two case–control studies evaluated cancer of the upper aerodigestive tract and exposure to tetrachloroethylene, or employment as a dry-cleaner, through personal interviews. Vaughan et al. (1997) reported odds ratios > 1 (not statistically significant) and dose–response or duration–response patterns for laryngeal cancer, although there were few exposed cases. Christensen et al. (2013) classified study subjects by degree of occupational exposure to tetrachloroethylene; none of the oesophageal cancer cases were exposed to tetrachloroethylene. [The study by Christensen et al. (2013) is an update of the study by Siemiatycki (1991).]

2.2.3. Lymphatic and haematopoietic cancers

See Table 2.4.

Table 2.4

Case–control studies of haematopoietic cancers and exposure to tetrachloroethylene.

Associations between haematopoietic cancers and occupational exposure to tetrachloroethylene have been evaluated in several case–control studies.

In a study in residents exposed to drinking-water contaminated by tetrachloroethylene in Cape Cod, Massachusetts, USA [described in Section 2.2.1] (Aschengrau et al., 1993), the odds ratio for leukaemia was 8.33 (95% CI, 1.53–45.29; two exposed cases) for people with estimated exposure above the 90th percentile. [There were few exposed cases and exposure to tetrachloroethylene was derived from a model.]

Occupational exposure to dry-cleaning fluids was assessed in a case–control study in the state of New York, USA (Kato et al., 2005). The study included incident cases of non-Hodgkin lymphoma in women aged 20–79 years diagnosed between October 1995 and September 1998; 722 were eligible and 376 were included. Population controls (aged < 65 years, from driving-licence records; aged > 65 years, from health-care records) were selected (1498 eligible, 463 included). Exposure data were collected via telephone interview. For the seven cases in people exposed to dry-cleaning fluids (not further specified), the odds ratio was 1.59 (95% CI, 0.49–5.13), after adjusting for several covariates.

In a case–control study of several haematological malignancies in 12 areas of Italy, incident cases in people aged 20–74 years diagnosed in 1991–1993 were recruited (Miligi et al., 2006; Costantini et al., 2008). The cases included diagnoses of non-Hodgkin lymphoma, including chronic lymphocytic leukaemia (821 men, 607 women); and Hodgkin lymphoma (159 men, 145 women), leukaemia (345 men, 241 women), and multiple myeloma (129 men, 134 women). Controls were randomly selected from the general population. Data on occupational history were collected by person-to-person interviews, and exposures assessed by experts. Age-adjusted Mantel–Haenszel odds ratios were calculated, or odds ratios were calculated with multiple logistic regression taking potential confounders into account. Fourteen cases of non-Hodgkin lymphoma had medium/high exposure to tetrachloroethylene (OR, 1.2; 95% CI, 0.6–2.5) (Miligi et al., 2006). For leukaemia, seven cases had medium/high exposure to tetrachloroethylene (OR, 1.0; 95% CI, 0.4–2.7) (Costantini et al., 2008).

A case–control study in six regions in Germany included 710 incident cases of malignant lymphoma in people aged 18–80 years and an equal number of population controls. Controls were identified from the population register, and recruitment continued until one participating control had been identified for each participating case. Face-to-face interviews were conducted. An industrial physician estimated cumulative exposure to tetrachloroethylene (intensity × frequency × years). The odds ratios associated with levels of exposure to tetrachloroethylene were 1.1 (95% CI, 0.5–2.3; 16 cases) for low exposure; 1.0 (95% CI, 0.5–2.2; 14 cases) for medium exposure; and 3.4 (95% CI, 0.7–17.3; six cases) for high exposure (Seidler et al., 2007).

Gold et al. (2011) conducted a case–control study in the Seattle-Puget Sound region of Washington and the Detroit metropolitan area of Michigan, USA, between 1 January 2000 and 31 March 2002. The analysis included 181 incident cases of multiple myeloma in people aged 35–74 years and 481 population controls selected by random-digit dialling (aged < 65 years) and from Medicare files (aged ≥ 65 years). In-person interviews were conducted with recording of occupational history and a job-exposure matrix for solvents was applied. Twenty-nine cases had ever been exposed to tetrachloroethylene (OR, 1.4; 95% CI, 0.9–2.4). A significant trend (P = 0.04) was observed with cumulative exposure level (intensity × frequency × years summed over all exposed jobs): in the highest exposure category, the odds ratio was 2.5 (95% CI, 1.1–5.4). In a further analysis excluding jobs for which the exposure assessor had low confidence the odds ratio was 1.5 (95% CI, 0.8–2.9) for ever exposure and 3.3 (95% CI, 1.2–9.5) in the highest category (Gold et al., 2011). [The Working Group noted that only half of the identified cases participated in the study.]

Cases in men aged 35–70 years diagnosed in Montreal, Canada, between September 1979 to June 1985 were included in a case–control study by Christensen et al. (2013) based on the population studied previously by Siemiatycki (1991). In total, 215 cases of non-Hodgkin lymphoma were recruited and 2341 cases of other cancers, and a population sample served as controls. Personal interviews were conducted and exposure was assessed by expert evaluation. Exposure to tetrachloroethylene was associated with an odds ratio of 1.7 (95% CI, 0.5–6.2; three exposed cases) when combining cancer and population controls, using proportional weighting.

2.2.4. Cancer of the kidney

See Table 2.5.

Table 2.5

Case–control studies of kidney cancer and occupational exposure to tetrachloroethylene.

Seven case–control studies have examined risk of cancer of the kidney associated with occupations involving exposure to tetrachloroethylene, particularly dry-cleaning. All studies except one conducted personal interviews with study subjects.

The study by Delahunt et al. (1995) was based on cancer-registry data and exposure assessment relied on occupational data recorded in the cancer registry. Two studies applied job-exposure matrices and classified subjects by degree of exposure to tetrachloroethylene (Dosemeci et al., 1999; Pesch et al., 2000b). In one study, a team of chemists and industrial hygienists translated job titles into potential exposures (Christensen et al., 2013). In one study, subjects were classified according to occupational exposure to dry-cleaning solvents (Mandel et al., 1995). In the remaining studies, subjects were classified by job title (Asal et al., 1988; Delahunt et al., 1995; Karami et al., 2012). All studies reported positive associations for men, or for women, or both, although statistical significance was only reached in three studies (Delahunt et al., 1995; Mandel et al., 1995; Pesch et al., 2000b), and one of them reported only crude risk estimates (Delahunt et al., 1995). Among the three studies that evaluated dose–response or duration–response trends (Mandel et al., 1995; Pesch et al., 2000b; Karami et al., 2012), only Karami et al. (2012) reported monotonic positive trends. Two studies reported protective (non-significant) associations among women (Dosemeci et al., 1999; Pesch et al., 2000b) and one study among men (Asal et al., 1988). [The study by Christensen et al. (2013) was based in the same population included in the study by Siemiatycki (1991), with refinements in exposure assessment and case classification.]

Environmental exposure to tetrachloroethylene has been evaluated in a case–control study (Aschengrau et al., 1993, described in Section 2.2.1) which included cancers of the kidney and other sites. None of the 35 kidney cancer cases were classified as exposed to tetrachloroethylene.

2.2.5. Cancer of the breast

Several analyses have been undertaken to evaluate the risk of cancer of the breast among women exposed to drinking-water contaminated with tetrachloroethylene in Cape Cod, Massachusetts, USA (Aschengrau et al., 1998, 2003; Vieira et al., 2005; Gallagher et al., 2011). The Working Group focused on the results of the latest re-analysis of these data (Gallagher et al., 2011). Study participants were permanent residents of eight towns in the Cape Cod region. Incident cancers of the breast diagnosed in 1983–1993 were identified from the Massachusetts cancer registry. Controls were demographically similar women living in Cape Cod in 1983–1993, identified by random-digit dialling (age < 65 years), from Medicare files (age ≥ 65 years), or death certificates. Telephone or personal interviews were used to collect residential history and other data. Exposure to tetrachloroethylene was estimated using modelling techniques (manual and automated algorithms). [The automated model redefined many unexposed subjects from the manual model as having low exposure.] The analysis included 930 cases and 1302 controls for the manual assessment, and 920 cases and 1293 controls for the automated assessment. Adjusted for age at diagnosis, vital status at interview, family history of breast cancer, personal history of breast cancer (before current diagnosis or index year), age at first live birth/stillbirth, occupational exposure, and study of origin, the odds ratio estimates based on the manual exposure assessment was 1.0 (95% CI, 0.8–1.2). Estimated exposure at > 75th and > 90th percentiles gave adjusted odds ratios of 1.6 (95% CI, 1.1–2.4) and 1.3 (95% CI, 0.7–2.6), respectively. For the automated assessment, the odds ratio was 1.3 (95% CI, 0.9–1.9). [There may be selection bias as only a small proportion of the selected controls could be reached.]

2.2.6. Cancer of the lung

See Table 2.6.

Table 2.6

Case–control studies of lung cancer and occupational exposure to tetrachloroethylene.

Two case–control studies of cancer of the lung investigated occupational exposure to tetrachloroethylene; both reported increased risks of lung cancer among those exposed to tetrachloroethylene after adjusting for smoking (Brownson et al., 1993; Vizcaya et al., 2013). One case–control study of cancer of the lung assessed residential exposure to tetrachloroethylene through contaminated drinking-water (Paulu et al., 1999). Results showed increased risks for those in the highest categories of exposure.

One of the studies of occupational exposure included cases in nonsmokers (Brownson et al., 1993). Both studies of occupational exposure conducted face-to-face personal interviews. Risks were reported by job title (Brownson et al., 1993) or by degree of exposure to tetrachloroethylene Vizcaya et al. (2013). Increased risks of cancer of the lung in female dry-cleaning workers were reported by Brownson et al. (1993) (OR, 1.8; 95% CI, 1.1–3.0), adjusted for age, smoking and previous lung disease. For lifetime nonsmokers, the odds ratio was 2.1 (95% CI, 1.2–3.7), adjusted for age and previous lung disease. Increased risk of cancer of the lung associated with exposure to tetrachloroethylene was reported by Vizcaya et al. (2013) (OR, 2.54; 95% CI, 1.25–5.26, for any exposure; and OR, 2.4; 95% CI, 0.8–7.7, for substantial exposure). [The study by Vizcaya et al. (2013) was a re-evaluation of the Siemiatycki (1991) study, including improved exposure assessment in the same study population.]

Paulu et al. (1999) conducted a population-based case–control study to evaluate the risk of cancers of the lung, colon and rectum, brain and pancreas associated with residential exposure to tetrachloroethylene. Cases were incident cancers diagnosed between 1983 and 1986, and resident in the upper Cape towns. Among the selected study subjects, 79.2% of cases of lung cancer, 83.2% of Medicare controls, and 81.1% of next-of-kin for deceased controls were contacted and interviewed. Among controls identified by random-dialling, 73.9% of the eligible and contacted subjects were interviewed. The relative delivered dose of tetrachloroethylene was estimated using a model that took into account residential location, duration of residence, water flow, and pipe characteristics. Adjusted odds ratios for cancer of the lung were moderately elevated among subjects whose exposure level was above the 90th percentile, whether or not a latent period was assumed [ORs and 95% CIs, 3.7 (1.0–11.7), 3.3 (0.6–13.4), 6.2 (1.1–31.6), and 19.3 (2.5–141.7) for 0, 5, 7, and 9 years of latency, respectively]. Results for other cancer sites considered in this study are reported in a subsequent section.

2.2.7. Cancer of the liver

See Table 2.7.

Table 2.7

Case–control studies of liver cancer and occupational exposure to tetrachloroethylene.

The risk of cancer of the liver associated with occupational exposure to tetrachloroethylene was evaluated in three case–control studies. Two studies included deceased subjects only, while the study by Christensen et al. (2013) included both living and deceased subjects. Exposure assessment was based on personal interviews with living study subjects (Christensen et al., 2013), company work history records (Bond et al., 1990) or occupation and kind of business or industry as recorded on the death certificate (Suarez et al., 1989). Subjects were classified by exposure to tetrachloroethylene (Bond et al., 1990; Christensen et al., 2013), or by job title (Suarez et al., 1989). Increased risk of cancer of the liver associated with exposure to tetrachloroethylene was reported by two studies (Bond et al., 1990; Christensen et al., 2013).

2.2.8. Cancer of the brain

See Table 2.8.

Table 2.8

Case–control studies of cancer of the brain and exposure to tetrachloroethylene.

Three case–control studies of cancer of the brain evaluated occupational exposure to tetrachloroethylene. None of the studies reported statistically significant increased risks.

Heineman et al. (1994) studied white men with astrocytic tumours in the USA. A total of 111 cases had job titles that were compatible with exposure to tetrachloroethylene (OR, 1.2; 95% CI, 0.8–1.6). None of the risk estimates for subgroups of increasing probability, duration or intensity of exposure reached statistical significance. Neta et al. (2012) evaluated glioma and meningioma in Arizona, Massachusetts and Pennsylvania in relation to occupational exposure to tetrachloroethylene. Exposure was evaluated through personal interviews, and odds ratios tended to be around 1 and non-statistically significant. These studies are described in more detail in the Monograph on trichloroethylene.

Ruder et al. (2013) evaluated glioma risk from non-farm occupational exposure (ever/never and estimated cumulative exposure) to tetrachloroethylene among 798 cases and 1175 population-based controls, aged 18–80 years and non-metropolitan residents of Iowa, Michigan, Minnesota, and Wisconsin, United States. Solvent use was estimated based on occupation, industry, and era, using a bibliographic database of published exposure levels and exposure determinants. Unconditional logistic regression was used to calculate odds ratios adjusted for frequency matching variables age group and sex, and age and education. Ever exposure to tetrachloroethylene was associated with reduced risk of glioma (OR, 0.8; 95% CI, 0.6–0.9, 299 cases and 500 controls exposed). Mean estimated cumulative exposure was similar for cases (3.5 ppm-years) and controls (3.1 ppm-years), with OR of glioma of 1.0 (0.9–1.1) for a 1-unit increase in natural-log transformed exposures in ppm–years. In analyses limited to 904 participant blood donors (excluding controls reporting a previous cancer diagnosis) genotyped for glutathione-S-transferases GSTP1, GSTM3, and GSTT1, solvent-exposed individuals with functional GST genes that might convert chlorinated solvents crossing the blood-brain barrier into cytotoxic metabolites were not at increased risk of glioma. [Study limitations include the high percentage of proxy case responses and the lack of workplace or serum measurements of solvent levels.]

Brain cancer and non-occupational tetrachloroethylene exposure was evaluated by Paulu et al. (1999) among 37 cases, in a study setting where exposure occurred through contaminated drinking-water. [Low numbers of brain tumours hampered the estimation of risks.] Only crude associations were reported, showing non-significant protective associations with wide confidence intervals.

2.2.9. Other cancers

Christensen et al. (2013) evaluated cancers of the prostate, colon, stomach and rectum, and melanoma associated with occupational tetrachloroethylene exposure. Substantial exposure was associated with a significant increased risk of prostate cancer (9 exposed cases; OR, 6.0; 95% CI, 1.2–30), and non-statistically significant increased risk of colon cancer (3 exposed cases; OR, 1.8; 95% CI, 0.3–11), stomach cancer (2 exposed cases; OR, 2.1; 95% CI, 0.3–17), rectal cancer (1 exposed case; OR, 1.1; 95% CI, 0.1–13) and melanoma (1 exposed case; OR, 2.6; 95% CI, 0.2–33). Pancreatic cancer was evaluated but no cases were exposed to tetrachloroethylene.

Environmental tetrachloroethylene exposure has been investigated by Paulu et al. (1999) (see Section 2.2.8) in relation to colorectal cancer (326 cases) and pancreatic cancer (37 cases). The adjusted ORs for colorectal cancer were modestly elevated among ever-exposed subjects, and did vary substantially as more years of latency were assumed. Adjusted ORs for rectal cancer among ever-exposed subjects were more elevated than the corresponding estimates for colon cancer. Low numbers for pancreatic cancer hampered the estimation of risks. Only crude associations were reported, showing non-significant protective associations with wide confidence intervals.

3. Cancer in Experimental Animals

The carcinogenicity of tetrachloroethylene in experimental animals was last reviewed by an IARC Working Group in 1995 (IARC, 1995), and more recently by the United States Environmental Protection Agency (EPA, 2012).

3.1. Mouse

See Table 3.1.

Table 3.1

Studies of carcinogenicity in experimental animals exposed to tetrachloroethylene.

3.1.1. Oral administration

Groups of 50 male and 50 female B6C3F₁ mice (age 5–7 weeks) were given tetrachloroethylene (purity, 99%) by gavage in corn oil on 5 days per week for 78 weeks (NCI, 1977; Weisburger, 1977). Groups of 20 male and 20 female mice were given vehicle only and served as controls. Dosage adjustments were made during the exposure period: male mice were given tetrachloroethylene at a dose of 450 or 900 mg/kg body weight (bw) for 11 weeks, and then at 550 or 1100 mg/kg bw for 67 weeks; female mice were given tetrachloroethylene at a dose of 300 or 600 mg/kg bw for 11 weeks, and then at 400 or 800 mg/kg bw for 67 weeks. Time-weighted average doses of tetrachloroethylene were 536 and 1072 mg/kg bw per day, respectively, for males, and 386 and 772 mg/kg bw per day, respectively, for females. The treatment period was followed by a 12-week observation period. Mortality was significantly increased in treated mice compared with controls. Significant dose-related positive trends and increased incidences of hepatocellular carcinoma in all treatment groups were observed in males and females. In male mice, the incidences were 2 out of 20 (vehicle controls), 32 out of 49 (lower dose), and 27 out of 48 (higher dose); the corresponding incidences in females were 0 out of 20, 19 out of 48, and 19 out of 48. Exposure to tetrachloroethylene caused toxic nephropathy (characterized in this study as degenerative changes in the proximal convoluted tubules at the junction of the cortex and medulla, with cloudy swelling, fatty degeneration, and necrosis of the tubular epithelium) in male mice (0/20, 40/49, 45/48) and female mice (0/20, 46/48, 48/48). A rare renal tubular cell carcinoma was observed in a male at the lower dose. [The Working Group noted that the study animals were housed in the same rooms as animals exposed to volatile agents, the group size for vehicle controls was small, and decreased survival and the 78-week exposure period reduced the power of this study to detect the full carcinogenic potential of the test agent.]

3.1.2. Inhalation

Groups of 49–50 male and 49–50 female B6C3F₁ mice (age, 8–9 weeks) were exposed to air containing tetrachloroethylene (purity, 99.9%) at concentrations of 0, 100, or 200 ppm (0, 680, or 1360 mg/m³) for 6 hours per day on 5 days per week for up to 103 weeks (Mennear et al., 1986; NTP, 1986). Survival was significantly reduced for males at both doses, and for females at the higher dose, compared with controls. Significant positive trends were observed in males for the incidence of hepatocellular adenoma and in both sexes for hepatocellular carcinoma. The incidence of hepatocellular carcinoma were also significantly increased at both doses in males (7/49, 25/49, 26/50) and females (1/48, 13/50, 36/50); and the incidence of hepatocellular adenoma or carcinoma (combined) was also significantly increased at both doses in males (17/49, 31/49, 41/50) and females (4/48, 17/50, 38/50). The incidence of hepatic degeneration was increased in male mice at both doses (2/49, 8/49, 14/50) and in female mice at the higher dose (1/49, 2/50, 13/50). The incidence of karyomegaly of renal tubular cells was also increased in exposed mice (males: 4/49, 17/49, 46/50; females: 0/48, 16/49, 38/50). [The Working Group noted that decreased survival reduced the power of this study to detect the full carcinogenic potential of the test agent.]

Groups of 50 male and 50 female Crj:BDF1 mice (age, 5 weeks) were exposed to air containing tetrachloroethylene (purity, 99%) at concentrations of 0, 10, 50, or 250 ppm [0, 68, 340, or 1695 mg/m³] for 6 hours per day on 5 days per week for up to 103 weeks (JISA, 1993; EPA, 2012). Survival decreased with increasing concentration among males and females; however, no statistical analysis of the survival data was provided. In males and females, significant positive trends in the incidences of hepatocellular adenoma, hepatocellular carcinoma, and hepatocellular adenoma or carcinoma (combined) were observed, and the incidences of these neoplasms were significantly increased in the group at the highest dose, compared with controls. The incidences of hepatocellular carcinoma were 7 out of 50 (control), 8 out of 50 (lowest dose), 12 out of 50 (intermediate dose), 25 out of 50 (highest dose) in male mice, and 0 out of 50, 0 out of 47, 0 out of 49, and 14 out of 49, respectively, in female mice. The incidences of hepatocellular adenoma or carcinoma (combined) were 13 out of 50, 21 out of 50, 19 out of 50, and 40 out of 50, respectively, in male mice, and 3 out of 50, 3 out of 47, 7 out of 49, and 33 out of 49 in female mice. The incidence of hepatic degeneration was also increased at the highest dose in males (1/50, 1/50, 4/50, and 37/50) and in females (0/50, 1/50, 2/50, and 30/50). In addition, there was a positive trend in the incidence of haemangiosarcoma of the liver and of the spleen in males, of haemangioma or haemangiosarcoma (combined) for all organs in males and females (primarily of the liver or spleen in males), and of Harderian gland adenoma in males (2/50, 2/50, 2/50, and 8/50). The incidence of karyomegaly of renal tubular cells was also increased in the highest dose compared with controls (males: 0/50, 0/50, 6/50, 38/50; females: 0/50, 0/50, 1/50, 49/50).

3.1.3. Skin application

Two groups of 30 female Ha:ICR Swiss mice (age, 6–8 weeks) were given tetrachloroethylene [purity not reported] at a dose of 18 or 54 mg per application in 0.2 mL of acetone by repeated topical application (three times per week) for at least 63 weeks. A control group of 30 mice was given an application of 0.1 mL acetone only (Van Duuren et al., 1979). The effects of exposure on survival were not reported. One skin papilloma occurred in a mouse at the lower dose; no skin tumours were observed among controls or in mice at the higher dose. [Interpretation of these findings was limited by the small number of animals tested, the short exposure duration, the incomplete reporting of results, and because the study did not address volatile loss of the test compound.]

3.1.4. Intraperitoneal injection

In a screening assay for induction and increased multiplicity of lung tumours, three groups of 20 male mice of strain A/St (age, 6–8 weeks) were given tetrachloroethylene (purity unspecified, but ≥ 95%) by intraperitoneal injection in tricaprylin, at doses of 80 mg/kg bw (14 injections), 200 or 400 mg/kg bw (24 injections), three times per week (Theiss et al., 1977). A group of 50 controls was given 24 injections of tricaprylin only. Twenty-four weeks after the first injection, the mice were killed, their lungs were examined under a dissecting microscope, and the number of surface adenomas was counted. Tetrachloroethylene did not increase the number of pulmonary adenomas per mouse in treated animals compared with controls. [The small number of animals studied and the short duration of exposure limited the interpretation of these findings. In addition, the lung was the only organ examined.]

4. Mechanistic and Other Relevant Data

4.1. Toxicokinetic data

4.1.1. Absorption

(a) Humans

Tetrachloroethylene is a lipophilic solvent of low relative molecular mass that readily crosses biological membranes. Pulmonary uptake is rapid, approaching steady-state within a few hours after the start of exposure.

In a study with six male volunteers, pulmonary uptake decreased during the course of the experiment to 60% of the initial value (Monster, 1979). Measured alveolar retention was 65%, averaged over six or seven volunteers (Monster et al., 1979; Chiu et al., 2007). Increased physical activity increases uptake, but lowers the alveolar partial pressure, thus removing more tetrachloroethylene from the alveoli, resulting in a longer time to reach tissue equilibrium (Pezzagno et al., 1988). The blood–air partition coefficient represents the ratio of the concentrations in the two media at steady-state, and is a factor in determining pulmonary uptake. The partition coefficient has been measured in vitro by means of vial-equilibrium methods (Gargas et al., 1989), and mean values ranged from 10 to 17 for humans (Sato & Nakajima, 1979; Koizumi 1989; Gearhart et al., 1993; Fisher et al., 1997; Mahle et al., 2007).

Data on oral absorption are limited. One case report of accidental ingestion suggested that tetrachloroethylene is also readily absorbed by this route of exposure (Köppel et al., 1985). Quantitative estimates of the bioavailability of tetrachloroethylene after oral intake in humans are not available, because the ingested amounts are not precisely known, and because the exposed subjects underwent hyperventilation therapy.

Dermal absorption of tetrachloroethylene vapours by humans has been reported to be relatively insignificant (only 1%) when compared with absorption via inhalation (Riihimäki & Pfäffli, 1978; Nakai et al., 1999). After liquid contact, skin absorption can be more significant: the amount of chemical absorbed during the immersion of one thumb in liquid tetrachloroethylene is equivalent to the uptake during inhalation of two to five times this amount during the same period (Stewart & Dodd, 1964). The permeability of tetrachloroethylene through skin was tested in a penetration model in vitro with human skin and skin of hairless guinea-pigs. The results for these two skin types were similar (Frasch & Barbero, 2009). Dermal absorption of tetrachloroethylene from contaminated soil has also been measured (Poet et al., 2002).

(b) Experimental systems

Inhalation studies in experimental animals have been conducted predominantly in adult males. Tetrachloroethylene is readily absorbed via the lungs into the systemic circulation (Pegg et al., 1979; Dallas et al., 1994a, b, 1995). Blood–air partition coefficients for tetrachloroethylene have been measured in vitro by means of vial-equilibrium methods (Gargas et al., 1989) and ranged from 13 to 21 for rodents (Koizumi 1989; Gearhart et al., 1993; Reitz et al., 1996; Mahle et al., 2007).

Oral doses of tetrachloroethylene – given by gavage or in drinking-water – are almost completely absorbed from the gut, as reported in several studies in mice, rats, and dogs (Pegg et al., 1979; Schumann et al., 1980; Frantz & Watanabe, 1983; Dallas et al., 1995).

Dermal uptake is minimal compared with pulmonary uptake during exposure to tetrachloroethylene vapour (Tsuruta, 1989), but is greater after direct application to the skin (Jakobson et al., 1982; Bogen et al., 1992). Permeability coefficients have been measured in vitro in several studies. Nakai et al. (1999) reported lower permeability into human skin for liquid tetrachloroethylene than for trichloroethylene or chloroform. Absorption of tetrachloroethylene from a contaminated soil matrix was higher in rats than in humans (Poet et al. 2002).

4.1.2. Distribution and body burden

(a) Humans

Once absorbed, tetrachloroethylene enters the blood circulation and undergoes rapid systemic distribution to tissues. The highest concentrations are expected to occur in adipose and other fatty tissue, due to the lipophilicity of the compound. Data on distribution of tetrachloroethylene in humans in vivo come from analyses of tissues taken from autopsies after fatal accidents. The available data show wide systemic distribution in blood and across all tissues tested, including the lung, liver, heart, kidney, and brain (Lukaszewski 1979; Levine et al., 1981; Garnier et al., 1996). Tetrachloroethylene has also been measured in human breast milk (Schreiber 1993, 1997; Schreiber et al., 2002).

Repeated daily exposure of human volunteers to tetrachloroethylene by inhalation resulted in accumulation of the compound in the body, with blood concentrations increasing over several days. Exhalation of the compound continued over several days due to its slow release from adipose tissue (Skender et al., 1991). For a given concentration in blood or air, the half time [the time required to equilibrate the adipose tissue to 50% of its final concentration] is about 25 hours (Monster, 1979). For persons exposed to tetrachloroethylene in a work schedule of 5 days per week, an equilibrium is established over 3−4 weeks.

The of tissue–blood partition coefficient has been measured in vitro by use of vial-equilibrium methods in human fat, kidney, muscle, and liver. The highest reported values are for fat (125), as expected due to the lipophilicity of tetrachloroethylene, with values for the remaining tissues ranging from 5 to 6 (Gearhart et al., 1993).

(b) Experimental systems

Studies in experimental animals have been conducted predominantly in adult males. These experiments provide clear evidence that tetrachloroethylene is distributed widely to all tissues of the body. In rats exposed in vivo, tetrachloroethylene has been detected and measured in blood, fat, brain, lungs, liver, kidneys, heart, and skeletal muscle. The highest tissue concentrations were found in adipose tissue (≥ 60 times that in blood) and in brain and liver (four and five times higher than in blood, respectively), as was calculated from rat tissue-distribution data (Savolainen et al., 1977; Dallas et al., 1994a, b). The concentration of tetrachloroethylene in fat was 9−18 times higher than the concentrations found in other tissues. Skeletal muscle contained the lowest concentration (Dallas et al. (1994b). Tetrachloroethylene readily crosses the blood–brain barrier (Savolainen et al., 1977; Schumann et al., 1980) and the placenta (Ghantous et al., 1986).

Partition coefficients have also been measured in vitro for a wide variety of tissues in rats and mice, including fat, liver, muscle, skin, kidney, and brain (Gargas et al., 1989; Koizumi 1989; Gearhart et al., 1993; Mattie et al., 1994; Mahle et al., 2007). The highest reported values were those for fat (90–110), whereas partition coefficients for the remaining tissues were in the range 1–4.

4.1.3. Metabolism

(a) Overview

Metabolism is critical to the various adverse effects of tetrachloroethylene in biological systems: with the exception of solvent effects that occur at extremely high exposures to tetrachloroethylene, all the adverse effects of tetrachloroethylene can be attributed to specific metabolites. The basic metabolic pathways for tetrachloroethylene have for the most part been deciphered over many years and have been summarized in various publications as well as a recent review (Green, 1990; IARC, 1995; Lash & Parker, 2001; EPA, 2012). This section will describe the major pathways in the metabolism of tetrachloroethylene, i.e. the cytochrome P450 (CYP)-dependent oxidative pathway and the glutathione (GSH)-conjugation pathway, in humans and experimental animals. Key urinary metabolites that are often used to estimate exposure in environmental or occupational settings have been identified. While the basic outline of the pathways has been known for many years, this section will focus on some of the more recently identified metabolites, particularly those described during the past decade. This section comprises four subsections: (i) an overview of the major pathways of tetrachloroethylene metabolism and the enzymes involved; (ii) a review of each step of the CYP-dependent pathway, providing evidence from humans or human tissues, and from experimental systems; (iii) a review of each step of the GSH-conjugation pathway, likewise providing data from humans or human tissues and from experimental systems; where appropriate, information on membrane transport of metabolites will be discussed; and (iv) a brief discussion of comparisons between the metabolism of tetrachloroethylene and trichloroethylene (see Monograph in this volume). Although tetrachloroethylene and trichloroethylene share several metabolic intermediates, have very similar metabolites, or are metabolized by similar enzymes, there are several important differences that need to be carefully considered.

Of the two major pathways, the flux through the oxidative pathway far exceeds that through the GSH-conjugation pathway. Whereas the latter generates several highly reactive metabolites, those generated by the oxidative pathway are in most cases chemically stable, although there are exceptions. [The Working Group noted that some of the chemically stable oxidative metabolites may be linked to adverse effects, but the different chemical reactivities of metabolites generated by the two pathways may render some metabolites in the GSH-conjugation pathway difficult to detect. Interpretations regarding the toxicological importance of such metabolites – based on quantitative differences in estimated flux – must, therefore, be made with caution.]

(i) CYP-dependent oxidation

The overall scheme of the metabolism of tetrachloroethylene via the CYP-dependent oxidative pathway is shown in Fig. 4.1. The initial step is catalysed by CYP and is believed to lead to the formation of tetrachloroethylene epoxide, although a transient intermediate of tetrachloroethylene with CYP may also occur (Yoshioka et al., 2002). Tetrachloroethylene epoxide may follow several reaction pathways (the quantitatively predominant route is indicated by the thicker arrow in Fig. 4.1): the epoxide may be de-chlorinated to oxalate dichloride and oxalate, which is excreted in the urine. Alternatively, the epoxide may be converted to trichloroacetyl aminoethanol (a urinary metabolite), which is a relatively minor pathway. The major metabolic route is conversion to trichloroacetyl chloride, which is subsequently converted to trichloroacetate, the major metabolite recovered in urine of tetrachloroethylene-exposed humans and animals. Finally, some of the trichloroacetate may be converted to dichloroacetate, which has been detected in urine, typically in very low amounts.

Fig. 4.1

Scheme for oxidative metabolism of tetrachloroethylene

The major oxidative metabolites formed from tetrachloroethylene, their site of formation or portal of entry, and the source of the information (animals and/or humans), is presented in Table 4.1. Systemic availability is dependent on the chemical stability of the metabolites: those that are relatively stable may be transferred from their site of formation into the blood stream and be delivered to other potential target organs, whereas those that are chemically unstable and reactive (tetrachloroethylene-oxide) tend to remain near their site of formation and react with cellular molecules, including DNA, proteins, and lipids.

Table 4.1

Formation and systemic availablility of tetrachloroethylene metabolites.

(ii) GSH-conjugation

As shown in Fig. 4.2, tetrachloroethylene undergoes an S_N2 nucleophilic displacement reaction with GSH, releasing a chloride ion under formation of S-(1,2,2-trichlorovinyl)glutathione (TCVG). Although this initial GSH-conjugation step can take place in many tissues, it occurs primarily in the liver as a result of first-pass metabolism and because of the high content of glutathione-S-transferases (GSTs): the various GST isoforms can account for as much as 5% of total cytosolic protein in rat or human liver. This initial step in the metabolism of tetrachloroethylene leads to the formation of reactive metabolites associated with toxic effects in the kidneys, or to a non-toxic mercapturate that is readily excreted in the urine.

Fig. 4.2

Scheme for glutathione-dependent metabolism of tetrachloroethylene

After formation of TCVG, which occurs predominantly in the liver but also in the kidneys (Lash et al., 1998), this metabolite is processed by γ-glutamyltransferase (GGT) and dipeptidase on the brush-border plasma membrane of the renal proximal tubular cell, to form the corresponding cysteine conjugate S-(1,2,2-trichlorovinyl)-l-cysteine (TCVC). Although GGT and dipeptidase activities are present in other tissues, the inter-organ pathways by which GSH and GSH-conjugates are processed effectively direct the GSH-conjugate to the kidneys.

The formation of TCVC represents a critical branch point in the GSH-dependent metabolism of tetrachloroethylene. This cysteine conjugate serves as a substrate for several enzymes that catalyse reactions towards its bioactivation to chemically reactive metabolites, or to its detoxification. The detoxification route involves N-acetylation by the microsomal enzyme N-acetyltransferase (NAT) to form N-acetyl-S-(1,2,2-trichlorovinyl)-l-cysteine (NAcTCVC). Although the latter product has been recovered in the urine of both rats and humans exposed to tetrachloroethylene (Bartels, 1994; Birner et al., 1996; Völkel et al., 1999), it can be metabolized via two alternative routes. First, as a substrate for acylase I, NAcTCVC can be deacetylated to regenerate TCVC (Uttamsingh & Anders, 1999). And second, it can undergo sulfoxidation as catalysed by CYP3A enzymes (CYP3A1/2 in rats and CYP3A4 in humans) (Werner et al., 1996). The resulting TCVC sulfoxide (TCVCS) is highly reactive and cytotoxic.

Apart from the metabolic changes in the mercapturate/mercapturate sulfoxide reaction pathway, TCVC is metabolized to reactive species by either cysteine conjugate β-lyase (CCBL) (Dekant et al., 1986a), which produces 1,2,2-trichlorovinylthiol (TCVT), or by a cysteine conjugate S-oxidase activity, identified as a catalytic function of flavin-containing monooxygenase 3 (FMO3) (Ripp et al., 1997), which forms TCVCS. Both TCVC and TCVCS can rearrange spontaneously to form a thioketene, which is the ultimate reactive and toxic acylating agent. These additional metabolic routes leading to the formation of the putative end product of the GSH-conjugation pathway highlight both the complexity of the metabolism of tetrachloroethylene along this pathway, and the potential difficulties in assessing the overall flux through the GSH-conjugation pathway by use of urinary NAcTCVC as a surrogate marker.

The site of formation and systemic availability for the major metabolites from the GSH-conjugation pathway is also presented in Table 4.1.

(iii) Enzymes involved in TCVC bioactivation

Of the two major bioactivation pathways for TCVC, i.e. with the enzymes CCBL or FMO3, the former has received most attention, but unlike for DCVC (Lash et al., 2000) it is unclear which of the two pathways predominates. The activity of CCBL is actually a catalytic function of a diverse array of enzymes (Cooper & Pinto, 2006; Lash, 2007) that has been detected not only in the kidneys, but also in liver and other tissues.

Studies in the mid-1960s first identified a thiol metabolite of a sulfonamide that was formed by a C–S lyase activity (Colucci & Buyske, 1965). Others subsequently identified hepatic and renal enzymes from cow and turkey that catalysed this reaction (Anderson & Schultze, 1965; Bhattacharya & Schultze, 1967). More than a decade later the term ‘cysteine conjugate β-lyase’ was first used to describe this activity in rat liver (Tateishi et al., 1978). All known CCBL enzymes contain pyridoxal-5-phosphate. Although the overall CCBL-catalysed reaction is the cleavage of a C–S-bond to yield a reactive thioacylating species, subsequent studies with the cysteine conjugate of trichloroethylene (i.e. DCVC) showed that the reaction mechanism proceeds via either a direct β-elimination or a transamination reaction with a suitable α-keto acid as co-substrate, to yield either the thiolate or a propionic-acid derivative, respectively; the latter is chemically unstable and rearranges to release the thiolate (Stevens et al., 1986; Elfarra et al., 1987).

Eleven mammalian enzymes are currently known to catalyse the CCBL reaction. Some of these enzymes catalyse both the β-elimination and the transamination reactions, whereas others only catalyse the former. The importance of each of these activities in TCVC bioactivation has been discussed (Cooper & Pinto, 2006; Cooper et al., 2011).

The flavin-containing monooxygenases (FMOs), like the CYP enzymes, represent a multigene family of enzymes. However, although there are more than 50 individual functional CYP enzymes from more than 40 gene families known in humans, only five FMO genes have been identified in mammals. Both systems have several characteristics in common, including localization in the endoplasmic reticulum, requirement for NADPH as a proton donor, and overall catalytic activity in a mixed-function oxidation reaction. Some of the functions of the FMOs are different, however. FMOs catalyse the oxidation of sulfur-, selenium-, and nitrogen-containing chemicals (Ziegler, 1993, 2002; Cashman & Zhang, 2006). Although some FMO and CYP450 enzymes share substrates and catalyse the same overall reactions, FMOs have some distinctive substrates, including cysteine S-conjugates of various halo-alkenes and halo-alkanes.

(b) Humans

(i) CYP-dependent oxidation

The predominant route in the metabolism of tetrachloroethylene in all species studied, including humans, is the CYP-dependent oxidation pathway (Reitz et al., 1996). This is particularly true at typical environmental exposures, because the various CYP enzymes that may act on tetrachloroethylene have higher affinities for tetrachloroethylene than do GSTs. Studies of overall metabolism in humans, however, suggest that the capacity of the CYP pathway to metabolize tetrachloroethylene readily saturates and is considered limited (Ohtsuki et al., 1983) and markedly lower than metabolic rates in experimental animals such as mice (Reitz et al., 1996). This conclusion was based on analyses of urine from workers exposed by inhalation to concentrations of tetrachloroethylene of up to 100 ppm for up to 8 hours. During the 8-hour exposure, 38% of the absorbed tetrachloroethylene is excreted unchanged through the lungs and < 2% of the absorbed dose is metabolized, as quantified by measurement of urinary metabolites (primarily trichloroacetate). Consistent with the conclusion that the total capacity for humans to metabolize tetrachloroethylene is limited, the reported half-life of tetrachloroethylene is 144 hours (Ikeda, 1977; Ikeda & Imanura, 1973).

The metabolism of tetrachloroethylene in humans has been modelled on the basis of literature data. The extent of metabolism was found to be quite variable and dependent on dose. Thus, at relatively high exposure levels of up to 144 ppm, as used in the study by Monster et al. (1979), < 2% of the absorbed dose was estimated to be metabolized. However, at ambient exposure levels (i.e. around 0.001 ppm, but as high as 1 ppm), the fraction of absorbed tetrachloroethylene estimated to be metabolized was > 36% (Bois et al., 1996).

The toxicokinetics of tetrachloroethylene in humans were also examined at an exposure level of 1 ppm by inhalation (Chiu et al., 2007). During and after a 6-hour exposure period, samples were taken from blood, urine, and alveolar breath at various time-points until up to 6 days after the exposure. The results were generally similar to those of earlier studies, but the variability and the substantial uncertainty in the model were emphasized. Major contributing factors were concentration-dependent differences in toxicokinetics, as previously concluded by Bois et al. (1996), and inter-individual differences in metabolism (Chiu et al., 2007).

(ii) GSH-conjugation pathway

Only a few studies are available on the metabolism of tetrachloroethylene via the GSH-conjugation pathway in humans or in human-derived tissues. However, the available data unambiguously confirm the existence of this pathway in vivo.

The urinary excretion of tetrachloroethylene metabolites was studied in six workers occupationally exposed in a dry-cleaning store, with ambient air concentrations of tetrachloroethylene of 50 ± 4 ppm. Four subjects were exposed for 8 hours per day, and two subjects for 4 hours per day. The major metabolites detected were trichloroacetate and trichloroethanol; the excretion pattern correlated closely with the duration of exposure of the individuals, with total amounts of 2,2,2-trichloro-compounds ranging from 13.5 to 65.0 nmol/mg creatinine. NAcTCVC was detected at concentrations approximately 5000 times lower (2.2–14.6 pmol/mg creatinine) (Birner et al., 1996).

In another study, three female and three male volunteers were exposed to tetrachloroethylene at 10, 20, and 40 ppm by inhalation for 6 hours. Over the 78 hours after the start of the exposure to the highest dose, a total of 20.4 ± 7.8 µmol of trichloroacetate and 0.21 ± 0.05 µmol of NAcTCVC were excreted. Again, while this study unequivocally demonstrated the presence of an active GSH-conjugation pathway in humans, it suggests that CYP-dependent oxidation greatly predominates. However, the relative flux through the two main pathways should not be estimated solely on the basis of urinary metabolites recovered. If that were done, the conclusion would be that no more than 1% of tetrachloroethylene is metabolized by GSH conjugation. Because NAcTCVC represents only one potential end product of the GSH-conjugation pathway, and since most of the end products are chemically reactive, these metabolites are likely to react with cellular nucleophiles, resulting in covalent adducts. DNA and protein adducts have indeed been found in incubations with tetrachloroethylene (Völkel et al., 1998, 1999).

(c) Experimental systems

(i) CYP-dependent oxidation

The interaction of tetrachloroethylene with hepatic microsomal CYP enzymes and the influence of various CYP inhibitors and inducers were studied in male Long-Evans rats. Trichloroacetate was the major metabolite and neither chloral hydrate nor trichloroethanol were detectable. Induction of CYP3A1 with pregnenolone-16α-carbonitrile, or CYP2B1/2 with phenobarbital both enhanced the metabolism of tetrachloroethylene, suggesting the involvement of these CYP enzymes (Costa & Ivanetich, 1980). In a later study, the absence of trichloroethanol in the urine of chronically dosed mice was confirmed; trichloroacetate was the only metabolite reported (Buben & O’Flaherty, 1985).

Evidence for a role of CYP2B enzymes in the metabolism of tetrachloroethylene was shown in studies with rat liver and enzyme-specific inducers and substrates. Tetrachloroethylene was shown to induce the CYP2B subfamily CYP. Unlike in the studies mentioned above (Costa & Ivanetich, 1980), there was no evidence for an involvement of CYP3A1 (Hanioka et al., 1995a, b). [The Working Group noted that the role of CYP2E1 in the metabolism of tetrachloroethylene has not been demonstrated directly in experimental animals, but is presumably based on the activity of this CYP with the congener trichloroethylene and with the fairly broad range of halogenated organic substrates of CYP2E1].

(ii) GSH-conjugation pathway

The presence of an active GSH-conjugation pathway for tetrachloroethylene has been demonstrated in vivo in experimental animals (rats and mice) through detection of NAcTCVC as a urinary metabolite (Bartels 1994; Dekant et al., 1986a). The initial step in the pathway, conjugation with GSH to form TCVG, has been shown to occur in rat liver (Dekant et al., 1987, 1998), which is presumably the primary site for most of this reaction in the body.

Because GSTs are found in most tissues, it was expected that TCVG formation could also occur in the kidneys. Accordingly, incubations of cytoplasm and microsomes from kidneys of F344 rats (both sexes) and B6C3F1 mice (both sexes) with 2 mM tetrachloroethylene and 5 mM GSH demonstrated readily measurable rates of TCVG formation (Lash et al., 1998). Metabolism in cytoplasm and microsomes from liver of both sexes of both species were also measured for comparison. Rates of GSH conjugation of TCVG were consistently higher in the corresponding fractions and tissues of males than in females in both species. In the kidneys, this difference was 2–3-fold for rats and 1.5–2-fold for mice. As expected, rates of TCVG formation in subcellular fractions of rat liver were 8–30 times higher than those in the corresponding kidney fraction from the same sex. While rates of TCVG formation were significantly higher in mice than in rats, the difference in rates between kidney and liver was much smaller in mice.

[The Working Group noted that although the higher rates of TCVG formation in male rats than in female rats correlates with the higher sensitivity of male rats to renal tumour formation from exposure to tetrachloroethylene, the markedly higher rates in mice of either sex does not correlate with the lack of renal tumours in this species (NTP, 1986).]

In contrast to the results described above, other investigators found no TCVG formation or much lower rates of GSH-conjugation of tetrachloroethylene. One study reported TCVG formation in rodent liver but not in human liver, and another showed TCVG formation in rat kidney at the limit of detection for the assay (i.e. 0.01 nmol/min per mg protein) (Dekant et al., 1987, 1998; Green et al., 1990). The latter value is similar to that reported by Lash et al. (1998).

The balance in the metabolism of tetrachloroethylene between CYP-dependent oxidation and GST-conjugation has been directly assessed in two studies.

Incubation of rat hepatocytes with either tetrachloroethylene or the prototypical GST-substrate 1-chloro-2,4-dinitrobenzene and NADPH resulted in a 70–85% reduction in the CYP-dependent oxidation pathway, suggesting that CYP-dependent oxidation can effectively compete with GST-conjugation in metabolizing tetrachloroethylene (Dekant et al., 1987).

The second study addressed the effect of modulating the two metabolic processes in isolated rat hepatocytes and kidney cells. Treatment with non-selective CYP450 inhibitors (e.g. SKF-525A, metyrapone) or with CYP2E1-selective inhibitors (e.g. chlorzoxazone, diethyldithiocarbamate) significantly stimulated TCVG formation in both cell types. Inhibition of the CYP-dependent metabolism also resulted in increased cytotoxicity of tetrachloroethylene, but only in isolated kidney cells (Lash et al., 2007). This finding highlights the importance of the GST-conjugation pathway for tetrachloroethylene-induced nephrotoxicity, but not hepatotoxicity (see Sections 4.5.1a and 4.5.2a for additional discussion of tetrachloroethylene-induced nephrotoxicity). Induction of CYP expression with either clofibrate or pyridine – compounds that enhance renal and hepatic expression of CYP2B1/2 and CYP2E1, respectively (Cummings et al., 1999, 2001) – resulted in increased hepatic CYP-dependent metabolism of tetrachloroethylene in both cases, and increased renal CYP-dependent metabolism of tetrachloroethylene after treatment with clofibrate, but no effect on renal CYP-dependent metabolism of tetrachloroethylene after treatment with pyridine. These results suggest that patterns of CYP-dependent metabolism of tetrachloroethylene differ in rat liver and kidney (Lash et al., 2007).

The differential roles of the CYP-dependent oxidation and GST-conjugation pathways in the bioactivation of tetrachloroethylene in rat liver and kidney were also demonstrated by modulation of the cellular GSH status. Treatment of freshly isolated rat hepatocytes with 5 mM methionine resulted in a ~50% increase in cellular GSH concentration and a significant reduction in tetrachloroethylene-induced cytotoxicity. In contrast, treatment of freshly isolated rat kidney cells with GSH at 5 mM resulted in a doubling of the cellular GSH concentration, but an increase in tetrachloroethylene-induced cytotoxicity. Conversely, depletion of tissue GSH with either l-buthionine-S,R-sulfoximine (BSO) or diethyl maleate resulted in increased cytotoxicity of tetrachloroethylene in isolated hepatocytes, but had no significant effect on cytotoxicity of tetrachloroethylene in isolated kidney cells. These results also demonstrate the distinct roles of the GSH-dependent metabolism of tetrachloroethylene in liver and kidney. In the liver, therefore, GSH plays its more traditional role with respect to tetrachloroethylene as an antioxidant and cytoprotective agent whereas in the kidneys, GSH functions primarily in the bioactivation and subsequent cytotoxicity of tetrachloroethylene (Lash et al., 2007).

Two studies provide information on the metabolism of TCVC by enzymes with cysteine conjugate β-lyase activity, leading to formation of reactive thioacylating intermediates. In the first study, a bacterial lyase and N-dodecylpyridoxal bromide were used as catalysts to convert TCVC into dichloroacetic acid (Dekant et al., 1988). In the second study, incubation of rat-kidney subcellular fractions with either tetrachloroethylene or TCVC produced Nε-(dichloroacetyl)-l-lysyl residues in proteins, primarily in mitochondria and cytoplasm. Formation of these adducts was inhibited by pre-incubation with the CCBL inhibitor amino-oxyacetic acid (AOAA), providing further evidence of the function of these enzymes (Birner et al., 1994).

Formation of a TCVC-sulfoxide metabolite was reported to result from incubations of TCVC with rat or rabbit kidney or liver microsomes that exhibited all the properties of an FMO isoenzyme. Of the five FMO isoenzymes, TCVC is a substrate only for FMO3 (Elfarra & Krause, 2007; Ripp et al., 1997; Novick & Elfarra, 2008).

Some of the cytotoxicity of TCVC that was independent of CCBL and FMO3 enzymes was shown to be actually due to formation of a mercapturic acid sulfoxide. By use of various selective inhibitors, including the CYP3A inhibitor troleanodomycin, it was shown that CYP3A enzymes were responsible for the sulfoxidation reaction (Werner et al., 1996). [The Working Group noted that rates of this reaction were within a factor of 2 to 3 of those for CCBL or FMO3, suggesting that this additional pathway may play a role in tetrachloroethylene bioactivation and nephrotoxicity.]

The kinetics of the N-acetylation of TCVC in liver and kidney of male and female Wistar rats were determined in vitro by incubation of microsomes isolated from these organs with TCVC. Rates of NAcTCVC formation were substantially higher in kidney than in liver, particularly in females. Upon administration of 40 µmol TCVC/kg bw to rats, 40% of the compound was excreted as the mercapturate during 48 hours, and the rest as unmodified cysteine conjugate. This excretion of mercapturate was markedly less than that observed with DCVC (see next section). The authors hypothesized that the more lipophilic conjugates were more readily excreted in an unmodified form (Birner et al., 1997).

(d) Comparison of the metabolisms of tetrachloroethylene and trichloroethylene

An understanding of the differences and similarities between the metabolism and pharmacokinetics of tetrachloroethylene and trichloroethylene is critical because much less direct information is available for tetrachloroethylene and extrapolations are often made from data with trichloroethylene. Despite the fact that trichloroacetate is a major oxidative metabolite of both chemicals, the rates of formation from tetrachloroethylene and trichloroethylene differ substantially. Trichloroethanol and its glucuronide are oxidative metabolites of trichloroethylene that have not been consistently detected after exposure to tetrachloroethylene, and results may have been confounded in some studies due to co-exposure with trichloroethylene. The available data suggest that tetrachloroethylene is less extensively metabolized than trichloroethylene in both humans and experimental animals because it is a much poorer substrate than trichloroethylene for the CYP-dependent oxidation pathway (Ohtsuki et al., 1983; Völkel et al., 1998; Lash & Parker, 2001). For example, maximal rates of tetrachloroethylene metabolism by CYP-dependent oxidation in rat-liver microsomes have been estimated to be 30 times lower than those for trichloroethylene (Costa & Ivanetich, 1980). Besides its lower affinity for CYPs, tetrachloroethylene is also more lipophilic than trichloroethylene and exhibits greater sequestration in fat than trichloroethylene. This fact alone would slow the distribution of tetrachloroethylene to sites of metabolism in comparison with trichloroethylene.

A major difference between the GSH-dependent metabolism of trichloroethylene and that of tetrachloroethylene is that amounts of TCVG formed in kidney cells of male rats were approximately 5-fold those of S-(1,2,-dichlorovinyl)glutathione (DCVG) (Lash et al., 1998, 2007). The fraction of total GSH-conjugation of trichloroethylene attributable to renal metabolism can be estimated to be 1.8%, and that of tetrachloroethylene 8.6%, i.e. 4.8-higher. In addition, oxidative metabolism of tetrachloroethylene in the liver is significantly slower than that of trichloroethylene. These data suggest that not only does renal GSH-conjugation make a relatively larger contribution towards overall GSH-conjugation for tetrachloroethylene than for trichloroethylene, but that GSH-conjugation contributes more towards the overall metabolism of tetrachloroethylene. The TCVC metabolite generated by CCBL is more chemically reactive than the metabolite generated by the action of CCBL on DCVC (Lash & Parker, 2001).

Besides differences related to the CCBL reaction route, differences also exist between the metabolic conversions of tetrachloroethylene and trichloroethylene in the FMO pathway. Studies with rabbit-liver microsomes showed that TCVC is overall a better substrate than DCVC for FMO3. Although the V_max for DCVC as substrate was sevenfold that for TCVC, the affinity of TCVC for the enzyme was nearly 20-fold (i.e. the K_m of FMO3 for TCVC was 20-fold lower than that for DCVC). Therefore, the catalytic efficiency of FMO3 towards TCVC is twice that towards DCVC. However, in a comparison of the kinetics of S-oxidation of TCVC and DCVC in bacterial membranes containing rabbit cDNA-expressed FMO3, the K_m for TCVC was about seven times lower than that for DCVC, while the V_max for DCVC was 50-fold that for TCVC. In this case, the catalytic efficiency with DCVC is sixfold that for TCVC (Ripp et al., 1997).

The kinetics of N-acetylation of DCVC and TCVC in hepatic and renal microsomes from male and female Wistar rats were investigated. The rates of N-acetylation for both cysteine conjugates were consistently higher in kidney than in liver. In addition, in both males and females and in both organs the V_max values for N-acetylation with TCVC as substrate were generally higher than those for DCVC (Birner et al., 1997).

[Considering the data for the metabolism of TCVC and DCVC by CCBL, FMO3, and the cysteine conjugate N-acetyltransferase (CCNAT), along with the marked difference in chemical reactivity of the thioketenes and sulfoxides generated from the two conjugates, the Working Group noted that one might expect renal proximal tubular cells to experience greater exposure to more reactive metabolites from tetrachloroethylene as compared with trichloroethylene. However, no data making this comparison directly are available.]

4.1.4. Excretion

(a) Humans

In humans, the main excretion route of tetrachloroethylene is by exhalation of the unchanged parent compound, with smaller amounts of metabolites excreted in the urine (Ikeda et al., 1972; Köppel et al., 1985; Monster, 1979). Based on measured concentrations in exhaled breath, pulmonary excretion has been estimated to account for 80–100% of the intake (Monster et al., 1979; Chiu et al., 2007). After cessation of exposure, pulmonary excretion occurs in multiple first-order phases due to release from different tissues, with initial half-lives in the range of 5 to 20 minutes, several intermediate phases, and terminal half-lives of around 50–65 hours (Guberan & Fernandez, 1974; Monster et al., 1979; Chien 1997). Urinary excretion of trichloro-metabolites (predominantly trichloroacetic acid) accounts for around 1–3% of intake (Stewart et al., 1970; Essing et al., 1973; Fernandez et al., 1976; Monster et al., 1979; Chiu et al., 2007), with urinary excretion of several GSH-derived metabolic products representing an even smaller fraction (Völkel et al., 1998). However, in these studies the urinary excretion was not followed for more than 3–7 days, and it is possible that a larger percentage of the tetrachloroethylene dose was eventually excreted in the urine. In studies that also measured pulmonary excretion, the entire dose was not always accounted for in the sum of exhaled tetrachloroethylene and urinary excretion of trichloroacetate (Monster et al., 1979; Chiu et al., 2007). Part of the administered dose may become metabolized to biotransformation products that were not measured, including oxidative products such as carbon monoxide, carbon dioxide, or oxalic acid, and additional GSH-conjugation products such as sulfoxides and reactive thiols. Physiologically based pharmacokinetic (PBPK) model-based estimates of the amount excreted via exhalation have ranged widely, with the most recent PBPK model predicting ranges of 90–99% via inhalation and 81–99% via ingestion (Chiu & Ginsberg, 2011).

(b) Experimental systems

In experimental rats and mice, excretion half-lives are in the order of hours, with pulmonary excretion virtually complete (> 99%) within 24 hours (Pegg et al., 1979; Schumann et al., 1980). This indicates that elimination is much more rapid in rodents than in humans. The extent of pulmonary excretion of unchanged tetrachloroethylene is dependent on species and dose. As exposure levels increase, the percentage of the compound excreted unchanged increases, which reflects saturation of metabolism (Pegg et al., 1979; Schumann et al., 1980). Pulmonary excretion appears greater in rats than in mice (Filser & Bolt 1979; Buben & O’Flaherty, 1985). The recently proposed PBPK model predicts the percentage tetrachloroethylene exhaled unchanged at exposures below saturation to be around 90–95% in rats and about 40–80% in mice, depending on the route of administration (Chiu & Ginsberg, 2011).

4.2. Genotoxicity and related effects

4.2.1. Humans

Several small cross-sectional studies have evaluated genotoxic and cytogenetic effects associated with exposure to tetrachloroethylene (Table 4.2). These studies have included assessments of the frequency of chromosomal aberrations and sister-chromatid exchange (SCE), the frequency of acentric fragments, and the presence of markers of oxidative stress.

Table 4.2

Molecular cross-sectional studies of genotoxicity and exposure to tetrachloroethylene.

(a) Chromosomal aberrations and sister-chromatid exchange

A cross-sectional study among 27 dry-cleaning workers and 26 controls in Japan reported no significant increase in the frequency of SCE in association with exposure to tetrachloroethylene. SCE was significantly increased in tetrachloroethylene-exposed male smokers compared with nonsmoking controls (Seiji et al., 1990).

A study of 10 tetrachloroethylene-exposed degreasing workers and 11 non-exposed controls found no significant increase in numerical or structural chromosomal aberrations or in frequency of SCE (Ikeda et al., 1980).

The frequencies of acentric fragments and chromosomal translocations – considered to be suitable indicators of chronic genotoxicity – were assessed in a cross-sectional study in the USA including 18 female tetrachloroethylene-exposed dry-cleaning workers, and 18 laundry workers not exposed to tetrachloroethylene. The average employment duration for the exposed dry-cleaners was 8 years. Air samples in the personal breathing-zone were collected from the dry-cleaning workers and from a subset of the laundry workers. A time-weighted average (TWA) exposure level of 3.8 ppm was measured in the exposed workers, while exposure levels were below the limit of detection in the controls. Chromosome painting was used to evaluate the frequency of cells with chromosomal translocations, insertions, dicentric and acentric fragments, and colour junctions. While the frequencies of each of these end-points, including translocations, were elevated in the exposed dry-cleaning workers compared with the controls, none of the increases were statistically significant (Tucker et al., 2011).

(b) Oxidative stress

An earlier cross-sectional study in 18 dry-cleaning workers and 20 laundry workers (all women) showed a significantly reduced level of 8-OH-dG in leukocytes of the dry-cleaning workers, but this could not be clearly attributed to exposure to tetrachloroethylene. There were no increases in other oxidative stress biomarkers in relation to exposure to tetrachloroethylene (Toraason et al., 2003).

4.2.2. Experimental systems

The genetic toxicology of tetrachloroethylene has been reviewed (Fabricant & Chalmers, 1980; Reichert, 1983; WHO, 1984; Vainio et al., 1985; Illing et al., 1987; European Centre for Ecotoxicology and Toxicology of Chemicals, 1990; Jackson et al., 1993; IARC, 1995; ATSDR, 1997b; EPA, 2012). The mechanisms by which tetrachloroethylene causes genotoxicity have been discussed (Henschler, 1987). Table 4.3 presents the studies of genotoxicity published to date. Highlights from these studies are given below.

Table 4.3

Genetic and related effects of tetrachloroethylene and trichloroacetyl chloride.

(a) DNA-and protein-binding

In a study in vivo, mice were exposed orally or by inhalation to tetrachloro[¹⁴C]ethylene. Labelling was observed in protein and RNA, but not in DNA of the liver (Schumann et al., 1980). In a more sensitive assay and after intraperitoneal injection of the radiolabelled compound, DNA-labelling was detected in mouse liver and kidney, and in rat and mouse stomach. Binding was highest in mouse liver and stomach. Metabolic activation was found to enhance binding of tetrachloroethylene to calf-thymus DNA in vitro (Mazzullo et al., 1987).

(b) Mutation induction in bacterial and fungal systems

Mutations were not generally observed after exposure of Escherichia coli or Salmonella typhimurium cells to tetrachloroethylene, with or without the standard metabolic activation by S9. In the diploid D7 strain of the yeast Saccharomyces cerevisiae, tetrachloroethylene caused mitotic gene conversion and recombination in one study (Callen et al., 1980), but failed to do so in two other studies (Bronzetti et al., 1983; Koch et al., 1988).

Tetrachloroethylene was not active in the SOS chromotest with E. coli and was not mutagenic to bacteria in the absence of metabolic activation. Purified tetrachloroethylene was not mutagenic to S. typhimurium or E. coli when tested in the presence of a metabolic-activation system prepared from rat-liver microsomes; however, a doubling of revertant frequencies was seen in S. typhimurium TA1535 in one study at both doses tested. In another study, purified tetrachloroethylene clearly increased the number of revertants in S. typhimurium TA100 in the presence of rat-liver GST, glutathione and kidney microsomes. This study was intended to simulate the multistep bio-activation pathway by GSH-conjugation (Vamvakas et al., 1989a). The mutagenicity was accompanied by time-dependent formation of S-(1,2,2-trichlorovinyl)glutathione, a pro-mutagen activated by kidney microsomes, and did not occur in the absence of GSH, GST, or kidney microsomes. Bile collected from an isolated rat-liver system perfused with tetrachloroethylene was clearly mutagenic in the presence of rat-kidney particulate fractions. In both assay systems, the mutagenicity was reduced, but not abolished, by the presence of the γ-glutamyl transpeptidase inhibitor, serine borate, and the β-lyase inhibitor AOAA, suggesting that the important steps in the metabolic activation of tetrachloroethylene in renal fractions are GST-mediated GSH-conjugation, followed by γ-glutamyl-transpeptidase-mediated formation of an S-cysteine conjugate, and bio-activation of the S-cysteine conjugate by β-lyase.

Tetrachloroethylene did not induce gene conversion, mitotic recombination or reverse mutations in yeast in stationary cultures. Both negative and positive findings were reported from studies of cultures in logarithmic growth phase, which stimulates xenobiotic metabolism; and positive results were obtained with tetrachloroethylene containing 0.01% thymol as a stabilizer. In a single study in yeast, tetrachloroethylene (analytical grade) weakly induced aneuploidy in growing cells capable of xenobiotic metabolism.

In single studies with Tradescantia, tetrachloroethylene [purity not given] induced mutations, and a compound of 99% purity induced a slight increase in the frequency of micronucleus formation.

(c) Micronucleus formation, SCE, and chromosomal aberrations

Tetrachloroethylene increased the frequency of micronucleus formation in hepatocytes, but not in peripheral blood reticulocytes of ddY mice given single intraperitoneal injections after, but not before, partial hepatectomy (Murakami & Horikawa, 1995). Micronucleus induction was not observed in a Chinese hamster lung cell line (CHL/IU) exposed to tetrachloroethylene (Matsushima et al., 1999). When Chinese hamster ovary (CHO K1) cells were exposed to tetrachloroethylene in a closed vapour-exposure system, a significant, dose-dependent increase in the frequency of micronuclei was found (Wang et al., 2001) Micronucleus induction was studied in AHH-1 human lymphoblastoid cells and in two daughter cell lines (h2E1 and MCL5) stably expressing various human metabolic enzymes. The parental AHH-1 cells possess native CYP1A1 activity and considerable GST activity; the h2E1 cells express human CYP2E1; and MCL-5 cells express human CYP1A2, 2A6, 3A4, 2E1, and microsomal epoxide hydrolase. Tetrachloroethylene induced an increase in micronuclei formation by threefold in AHH-1 cells and ninefold in h2E1 and MCL-5 cells (Doherty et al., 1996). Similar results were reported with the MCL-5 cell line (White et al., 2001).

Tetrachloroethylene-induced DNA damage was not observed in the SCE assay in cultured human blood cells at a dose that reduced viability by 40% due to cytotoxicity (Hartmann & Speit, 1995). Neither chromosomal aberrations nor SCE were induced in cultured Chinese hamster ovary cells after exposure to tetrachloroethylene (Sofuni et al. 1985; Galloway et al., 1987). Chinese hamster ovary cells exposed to tetrachloroethylene in the presence or absence of S9 fraction (derived from livers of Sprague Dawley rats) showed no increase in SCE frequency (NTP, 1986). Beliles et al. (1980) assessed chromosomal aberrations and aneuploidy in bone marrow of male and female Sprague-Dawley rats after single and short-term exposures to tetrachloroethylene by inhalation. The only effect reported with a single exposure was a slight increase in the percentage of cells with aberrations and aneuploidy in male, but not female rats. No significant effects were observed in any of the groups exposed for short periods. No chromosomal aberrations were found in Chinese hamster ovary cells exposed to tetrachloroethylene with or without metabolic activation (NTP, 1986).

Studies in Drosophila melanogaster were negative for sex-linked recessive lethal mutations (Beliles et al., 1980; Valencia et al., 1985; NTP, 1986).

(d) Unscheduled DNA synthesis and DNA strand breaks

Human fibroblasts (WI 38 cells) were tested for the induction of unscheduled DNA synthesis after exposure to tetrachloroethylene; the results were equivocal (Beliles et al., 1980). However, the positive controls were only weakly positive in this study. In other studies, no evidence of unscheduled DNA synthesis was observed in human lymphocytes, human fibroblasts, or rat and mouse hepatocytes (Perocco et al., 1983; Costa & Ivanetich, 1984; Shimada et al., 1985; Milman et al., 1988).

The results of the few assays for DNA strand break after exposure to tetrachloroethylene in vivo were equivocal. DNA single-strand breaks were measured in the liver and kidney of male mice exposed by intraperitoneal injection, but this effect was reversible within 24 hours (Walles, 1986). A second study examined DNA strand breaks after oral exposure of male F-344 rats to tetrachloroethylene for 1 week, and demonstrated no DNA breakage (Potter et al., 1996). A recently published report on DNA strand breaks in hepatocytes showed a marginal increase in tail intensity in the comet assay after oral exposure of mice to tetrachloroethylene (Cederberg et al., 2010); the statistical and biological significance of this result has been disputed (Lillford et al., 2010; Struwe et al., 2011).

(e) Cell transformation

Treatment with tetrachloroethylene for 3 days without metabolic activation did not induce cell transformation in BALB/c 3T3 cells after a 30-day post-treatment incubation period (Tu et al., 1985). However, cells from Fischer rat embryos were transformed upon treatment with tetrachloroethylene in the absence of metabolic activation (Price et al., 1978).

(f) Genotoxicity of metabolites of tetrachloroethylene

A limited number of experimental studies on the genotoxicity of tetrachloroethylene metabolites have been performed (see Table 4.4).

Table 4.4

Studies of genotoxicity with metabolites of tetrachloroethylene.

Trichloroacetyl chloride results from oxidative metabolism of tetrachloroethylene, and has been tested for mutagenicity in S. typhimurium, with inconsistent results. An early study found no mutagenicity after incubation in liquid suspension with S. typhimurium TA98 and TA100 strains, with or without S9 activation (Reichert et al., 1983). In a second study, trichloroacetyl chloride as a vapour was tested for mutagenicity in S. typhimurium TA100 and found to give positive results in the presence or absence of metabolic activation; the chemical induced mostly GC > TA transversions (the predominant background mutation). Trichloroacetyl chloride gave negative results for prophage induction in E. coli in the same study (DeMarini et al., 1994).

Tetrachloroethylene epoxide, an intermediate in the CYP450-mediated oxidative metabolism of tetrachloroethylene (Henschler, 1977; Henschler & Bonse, 1977), has been tested for mutagenicity in a single study. It was mutagenic in S. typhimurium TA1535, but not in E. coli WP2uvrA (Kline et al., 1982). Mutagenicity was observed at the lower doses in S. typhimurium, but not at higher doses, most likely due to cytotoxicity.

Only a small number of studies were available that assessed the genotoxicity of metabolites in the GSH-conjugation pathway of the metabolism of tetrachloroethylene.

TCVG formed from tetrachloroethylene in isolated perfused rat liver and excreted into bile was mutagenic in S. typhimurium in the presence of a rat-kidney homogenate, which contained high concentrations of GGT (Vamvakas et al., 1989a). In this study, the mutagenicity assay was conducted with Salmonella strains TA100, TA98, and TA2638, and with tetrachloroethylene, TCVG, and bile from liver perfusates of tetrachloroethylene-exposed rats. The results show that the GST metabolites, or tetrachloroethylene in the presence of bile containing GST, led to gene mutations in S. typhimurium TA100. In a more recent study, TCVG showed an unequivocal dose-dependent mutagenic response in Salmonella TA100 in the presence of S9 protein fraction from rat kidney; TCVC was mutagenic without metabolic activation in this strain (Dreessen et al., 2003). TCVC (1−10 nmol/plate) was also mutagenic in Salmonella strains TA98 and TA100, but not in TA2638, and β-lyase activity was blocked by the addition of AOAA (Dekant et al., 1986b). A further study from the same group indicated that Salmonella bacteria were capable of deacetylating the urinary metabolite NAcTCVC (50−100 nmol/plate) when TA100 showed a clearly positive response without exogenous activation (Vamvakas et al., 1987). Addition of cytosolic protein increased the mutagenic response, while addition of the β-lyase inhibitor AOAA reduced it.

A concentration-related increase in unscheduled DNA synthesis was found in LLC PK1 cells (derived from porcine kidney) exposed to TCVC; this effect was abolished by a β-lyase inhibitor. To determine cytotoxicity, release of lactate dehydrogenase was measured, but no increase was found (Vamvakas et al., 1989c).

4.3. Non-genotoxic effects and organ toxicity

4.3.1. Kidney

The available studies in humans and experimental animals have addressed multiple non-genotoxic mechanisms for kidney carcinogenicity associated with exposure to tetrachloroethylene. These include accumulation of α2u-globulin, cytotoxicity unrelated to α2u-globulin, and peroxisome proliferator-activated receptor-α (PPARα) activation.

(a) Accumulation of α2u-globulin

Accumulation of α2u-globulin is a histopathological phenomenon elicited in the kidney of the male rat by long-term exposure to chemicals. The hypothesized sequence of key events comprises:

• Excessive accumulation of hyaline droplets containing α2u-globulin in renal proximal tubules;
• Subsequent cytotoxicity and single-cell necrosis of the tubule epithelium;
• Sustained regenerative tubule cell proliferation;
• Development of intraluminal granular casts from sloughed cellular debris associated with tubule dilatation and papillary mineralization;
• Foci of tubule hyperplasia in the convoluted proximal tubules;
• Tumours of renal tubules.

Seven criteria are specified for demonstrating the α2u-globulin mechanism for carcinogenesis in male rat kidney (IARC, 1999), namely:

• Characteristic histopathology
• Specificity to male rats
• Accumulation of α2u-globulin
• Reversible binding to α2u-globulin
• Increased cell proliferation
• Similarities in dose–response relationships for histopathology and tumour outcome
• Lack of genotoxicity

This mechanism is posited to occur only in rodents; accordingly, only studies in experimental animals were identified, and are discussed below.

Three studies provide evidence satisfying four of the seven above-mentioned criteria (characteristic histopathology, specificity for the male rat, accumulation of α2u-globulin, and increased cell proliferation) for supporting the α2u-globulin mechanism, at doses of tetrachloroethylene in excess of those observed to induce tumorigenesis. These studies demonstrate that tetrachloroethylene induces accumulation of α2u-globulin and hyaline-droplet nephropathy in male rats (see Table 4.5).

Table 4.5

Formation of renal α2u-globulin in rodents exposed to tetrachloroethylene.

Increased α2u-hyaline droplet formation was seen in male, but not female, F344 rats treated by gavage for 10 days with tetrachloroethylene at 1000 mg/kg bw per day. This finding was correlated with both protein-droplet nephropathy (crystalloid accumulation) and enhanced cellular proliferation. Cell replication was increased in the male rats specifically in damaged P₂ segments, suggesting a link between the α2u-globulin accumulation and the ensuing proliferative response (Goldsworthy et al., 1988).

In short-term, high-dose, studies, oral administration of tetrachloroethylene at 1500 mg/kg bw per day for up to 42 days caused accumulation of α2u-globulin in the proximal renal tubules of male rats (Green et al., 1990). [The Working Group noted the lack of a parallel experiment in female rats in this study].

Accumulation of α2u-globulin was also demonstrated to occur in P₂ segments of proximal tubule cells after oral exposure of male, but not female, rats to tetrachloroethylene at 500 mg/kg bw per day in corn oil 4 weeks (Bergamaschi et al., 1992).

The primary limitation to the mechanistic support for the α2u-globulin mechanism concerns the criterion of similarities in dose–response relationships for histopathology and tumour outcome. The NTP cancer-bioassay (NTP, 1986) did not provide evidence of hyaline droplets in rats exposed to carcinogenic doses of tetrachloroethylene for up to 2 years. However, the NTP protocol at that time was not designed specifically to detect hyaline droplets or accumulation of α2u-globulin in the kidney (NTP, 1990). In addition, the nephropathy observed at the end of a 2-year bioassay would be difficult to distinguish from the nephropathy associated with advanced age in these rats. Other relevant findings concerning the correspondence in dose–response relationships for histopathology and tumour outcome are those reported by Green et al. (1990), who found no evidence of hyaline-droplet formation in tests with lower doses of inhaled tetrachloroethylene of up to 400 ppm for 6 hours per day, for 28 days. Because animals were killed up to 18 hours after termination of the final exposure, recovery may have been possible. The authors raised the possibility that a longer exposure to tetrachloroethylene at 400 ppm would be required for the hyaline-droplet accumulation in the rat kidney. However, accumulation has been demonstrated after short-term exposure (even after a single dose) to several agents, such as d-limonene, decalin, unleaded gasoline, and trimethylpentane (Charbonneau et al., 1987; NTP, 1990). The renal pathology reported in the NTP bioassay is also not entirely consistent with the general findings for other chemicals that induce accumulation of α2u-globulin (NTP, 1986). For example, mineralization in the inner medulla and papilla of the kidney was not seen with tetrachloroethylene, but is a frequent finding in bioassays with chemicals that induce accumulation of α2u-globulin (e.g. for pentachloroethane, the incidence of renal papillar mineralization was 8% in controls, 59% in the group at the lowest dose, and 58% in the group at the highest dose) (NTP, 1983).

Concerning the remaining two criteria, no direct evidence demonstrating binding to α2u-globulin was identified. The evidence presented in Section 4.2 does not clearly rule out the potential role of genotoxicity, particularly in the kidney. Indeed, metabolites of tetrachloroethylene known to be produced in the kidney (e.g. TCVG and NAcTCVC) have been demonstrated to be genotoxic in vitro. In one study in mammalian cells, unscheduled DNA synthesis in porcine kidney cells was observed to increase in a dose-dependent manner after exposure to TCVC (Vamvakas et al., 1989c). Bacterial assays found TCVG (Vamvakas et al., 1989a; Dreessen et al., 2003) and NAcTCVC (Vamvakas et al., 1987) to be mutagenic in the presence of metabolic activation, while TCVC was mutagenic in the absence of activation (Dreessen et al., 2003).

(b) Cytotoxicity and sustained chronic nephrotoxicity, not associated with α2u-globulin

This hypothesized mechanism for development of renal neoplasms involves renal cytotoxicity and subsequent cellular proliferation without regard to accumulation of α2u-globulin. Experimental evidence in humans and animals supporting this mechanism is summarized below.

(i) Humans

The renal toxicity of tetrachloroethylene has been demonstrated in studies with patients receiving high intentional exposures, and in occupational settings. High concentrations of inhaled tetrachloroethylene given as an anaesthetic are associated with symptoms of renal dysfunction, including proteinuria and haematuria (Hake & Stewart, 1977; ATSDR, 1997a). The study by Calvert et al. (2011) supports an association between inhalation exposure to tetrachloroethylene and end-stage renal disease, particularly hypertensive end-stage renal disease. There was an increase of more than 2.5-fold in incidence (SIR, 2.66; 95% CI, 1.15–5.23; 15 cases) among subjects who worked in a shop where tetrachloroethylene was the primary cleaning solvent compared with the expected incidence based on rates in the USA population. An exposure–response pattern was further suggested because the risk for hypertensive end-stage renal disease was highest among those employed for 5 years (SIR, 3.39; 95% CI, 1.10–7.92; five cases).

Other studies of the chronic effects of inhaled tetrachloroethylene on the kidney used measurements of urinary renal proteins as an indicator of kidney function. No effect on several urine parameters or blood urea nitrogen (a measure of kidney function) was reported with controlled inhalation exposure to tetrachloroethylene (25 or 100 ppm for 11 weeks, 12 healthy individuals) [Stewart et al. (1977), as reported in ATSDR (1997a)]. However, Mutti et al. (1992) observed an elevated prevalence of abnormal values for brush-border antigens, a higher geometric mean concentration of brush-border antigens in urine, and a higher concentration of tissue non-specific alkaline phosphatase in urine among 50 exposed dry-cleaning workers compared with 50 blood donors matched by sex and age with the exposed group. The markers of renal damage were highly predictive of exposure status in discriminant analyses. The amount of β₂-microglobulin was not elevated among exposed subjects as compared with controls in this and two other studies that examined this protein (Lauwerys et al., 1983; Vyskocil et al., 1990). In two studies that measured β-glucuronidase or lysozyme, respectively, a statistically significant increase was reported in mean urinary concentration of these proteins among dry-cleaning workers compared with controls (Franchini et al., 1983; Vyskocil et al., 1990).

Several studies examined urinary indicators of renal tubule function – retinol-binding protein, N-acetyl-β-d-glucosaminidase, or alanine aminopeptidase – in workers in dry-cleaning exposed to tetrachloroethylene. One study reported a statistically significantly increased prevalence of abnormal values of retinol-binding protein, but no difference in geometric mean concentration between exposed and controls (Mutti et al., 1992). Another study did find a higher geometric mean concentration of retinol-binding protein for exposed workers compared with controls (Verplanke et al., 1999). However, no effect of tetrachloroethylene was seen in four studies that measured urinary excretion of N-acetyl-β-d-glucosaminidase (Mutti et al., 1992; Verplanke et al., 1999; Trevisan et al., 2000) or in one that measured alanine aminopeptidase (Verplanke et al., 1999).

Primary cultures of proximal tubular cells from both rat and human kidney were used to study the role of CCBL in the acute cytotoxicity caused by DCVC, TCVC, and two fluorinated cysteine conjugates of halogenated solvents. Incubation in the presence of the CCBL inhibitor AOAA resulted in partial protection only. Nonetheless, the study demonstrated a requirement for CCBL-dependent metabolism for DCVC to exert a toxic effect on human kidney cells. TCVC was less cytotoxic than DCVC. CCBL activity in proximal tubular cells from the rat kidney was threefold that in the human cells (McGoldrick et al., 2003).

(ii) Experimental animals

Adverse effects on the kidney have been observed in studies of rodents exposed by inhalation (JISA, 1993; NTP, 1986) and oral gavage (NCI, 1977; Goldsworthy & Popp, 1987; Goldsworthy et al., 1988; Green et al., 1990; Ebrahim et al., 1996, 2001; Jonker et al., 1996; Philip et al., 2007).

While neoplasia in the renal tubules is observed to occur only in male rats, tetrachloroethylene has been reported to produce nephrotoxicity across species, and in both sexes. Signs of tetrachloroethylene-induced kidney damage appeared in both rats and mice during the early phases of the NTP cancer bioassay (inhalation study), for example, indicating that animals of both species surviving to the scheduled termination of the study had long-standing nephrotoxicity. Although the female rats did not develop any tumours in the renal tubules, the incidence of karyomegaly was significantly elevated in females as well as in males, and one of the 50 female rats exposed at the highest dose developed tubul cell hyperplasia (NTP, 1986).

In the NTP inhalation study with mice, ‘nephrosis’ – generally defined as non-inflammatory degenerative kidney disease – was noted to occur at increased incidences in dosed females, casts (cylindrical structures formed from cells and proteins released from the kidney) were observed at increased frequency in exposed males and in females at the highest dose, and karyomegaly of the tubule cells was seen at increased incidences in both sexes of exposed mice (NTP, 1986). The severity of the renal lesions was dose-related, and one male at the lowest dose had a renal tubule cell adenocarcinoma. In the NCI cancer bioassay (gavage study) in B6C3F₁ mice and Osborne-Mendel rats treated with tetrachloroethylene, toxic nephropathy was not detected in control animals, but did occur in both male and female rats as well as in mice (NCI, 1977).

Nephrotoxicity after exposure to tetrachloroethylene administered by inhalation was observed in a 2-year cancer bioassay in groups of 50 male and female Fischer rats (0, 50, 200, or 600 ppm) and Crj:BDF1 mice (0, 10, 50, or 250 ppm) exposed for 6 hours per day, 5 days per week, for 104 weeks. Compared with controls, survival was decreased in all groups at the highest dose; this decrease was considered to be treatment-related. Relative kidney weight was increased in male and female rats (exposed at 200 or 600 ppm) and in male and female mice (exposed at 250 ppm). Karyomegaly in the proximal tubules of the kidneys was observed among male and female rats and mice. An increase in atypical tubular dilation of the proximal tubules was noted in male and female rats at the highest dose, and exacerbation of chronic renal disease was observed in male rats at the highest dose only (JISA, 1993).

Hayes et al. (1986) reported renal effects in rats exposed to tetrachloroethylene in drinking-water. The rats were given nominal amounts of 14, 400, and 1400 mg/kg bw per day for 90 consecutive days. There were no treatment-related deaths. Increased kidney-to-body weight ratios were observed.

Nephrotoxicity and increased relative kidney weights were observed in female Wistar rats treated with tetrachloroethylene at 600 or 2400 mg/kg bw per day in corn oil by gavage for 32 days. One rat at the higher dose died as a result of the treatment. Nephrotoxic effects were noted at the higher dose, with significant changes in all clinical chemistry markers related to kidney function (urea, total protein, albumin, N-acetyl-β-d-glucosaminidase) measured in the urine at the end of week 1 or week 4, except for urinary density, glucose, and creatinine. Karyomegaly was also observed at the higher dose in four out of five animals exposed (Jonker et al., 1996).

Oral administration of tetrachloroethylene in sesame oil (3000 mg/kg bw per day for 15 days) to male and female albino Swiss mice caused a significant increase in kidney weight, an increase in glomerular nephrosis, and a decrease in blood glucose concentrations compared with controls (Ebrahim et al., 1996). Concurrent administration of 2-deoxy-d-glucose (500 mg/kg bw per day, intraperitoneal injection) or vitamin E (400 mg/kg bw per day, gavage) prevented tetrachloroethylene-induced biochemical and pathological alterations. Exposure to tetrachloroethylene alone led to a decrease in blood glucose concentrations, which returned to near-normal levels with concomitant exposure to 2-deoxy-d-glucose and vitamin E. Elevated levels of glycolytic and gluconeogenic enzymes after exposure to tetrachloroethylene were also observed to decrease to near-normal levels after exposure to these two agents. Histopathology of the kidney showed hypercellular glomeruli after exposure to tetrachloroethylene, but this was not observed in mice treated with tetrachloroethylene and 2-deoxy-d-glucose, or tetrachloroethylene and vitamin E (Ebrahim et al., 1996).

Mechanistic information on the nephrotoxicity of tetrachloroethylene was relatively sparse. Most studies have concentrated on the metabolites in the GSH pathway rather than on the parent compound, because much of the available information for both tetrachloroethylene and trichloroethylene suggests that this pathway generates the reactive chemical species responsible for nephrotoxicity.

The role of the GSH metabolites of tetrachloroethylene, particularly TCVC and TCVCS, in kidney toxicity was examined in a study in two groups of four male Sprague-Dawley rats exposed to TCVC or TCVCS (115 or 230 μmol/kg bw in saline) given by single intraperitoneal injections. The rats were killed 24 hours after dosing. Serum was analysed for blood urea nitrogen, and urine samples were analysed for γ-glutamyl transpeptidase activity as markers of nephrotoxicity. Rats exposed to the higher dose of TCVCS showed visible signs of kidney necrosis, while none of the other treated groups did. Histologically, kidneys from rats exposed to TCVC or TCVCS at the lower dose showed slight-to-mild acute tubular necrosis. Analysis of kidneys at 24 hours after exposure showed mild-to-moderate acute tubular necrosis in rats exposed to TCVC at the higher dose, and severe tubular necrosis in those exposed to TCVCS at the higher dose. A significant fourfold increase in blood urea nitrogen was observed in rats exposed to TCVCS at the higher dose compared with controls, but no significant increases were noted after exposure to TCVC. Variable increases in urinary glucose concentrations and γ-glutamyl transpeptidase activity were seen after exposure to TCVC or TCVCS. A second part of this experiment demonstrated enhanced toxicity by pre-treatment with the β-lyase inhibitor AOAA (500 μmol/kg bw), given by intraperitoneal injection 30 minutes before administration of TCVC at the higher dose. In a third experiment, groups of four rats were exposed to TCVC or TCVCS (higher dose) and killed after 2 hours to investigate non-protein thiol status in the kidney. TCVCS significantly decreased non-protein thiols, but did not affect non-protein disulfides, whereas TCVC was without effect. Histological examination of the kidneys showed scattered foci of mild acute tubular necrosis (after TCVC) or widespread acute tubular necrosis, intratubular casts, and interstitial congestion and haemorrhage (after TCVCS). These results show that TCVCS has greater nephrotoxicity than TCVC (Elfarra & Krause, 2007)

The tetrachloroethylene-S-conjugate metabolites TCVG and TCVC caused dose-related cytotoxicity in renal cell preparations, which was prevented by a β-lyase enzyme inhibitor. Renal β-lyases are known to cleave TCVC to yield an unstable thiol, 1,2,2-trichlorovinylthiol, which may give rise to formation of a highly reactive thioketene, a chemical species that can form covalent adducts with cellular nucleophiles (Vamvakas et al., 1989d). In addition, sulfoxidation of both TCVC and its N-acetylated product resulted in formation of toxic metabolites (Werner et al., 1996; Ripp et al., 1997). A study by Lash et al. (2002) characterized the cytotoxicity of tetrachloroethylene and TCVG in suspensions of isolated kidney cells from male and female F344 rats and the mitochondrial toxicity of tetrachloroethylene and TCVG in suspensions of renal cortical mitochondria from the kidneys of male and female F344 rats and B6C3F₁ mice. In both cases, responses to tetrachloroethylene and TCVG were compared with those to trichloroethylene and DCVG, respectively, from a parallel study (Lash et al., 2001). Although the parent compounds are not particularly potent as acute cytotoxic agents, both tetrachloroethylene and trichloroethylene at concentrations of 1 mM each produced a modest degree of cytotoxicity in 3-hour incubations of isolated kidney cells from male F344 rats, as assessed by release of lactate dehydrogenase; tetrachloroethylene and trichloroethylene caused 38% and 24% release, respectively. In contrast, neither parent compound produced significant release of lactate dehydrogenase in isolated kidney cells from female rats. A larger difference was observed when the cytotoxicity of the GSH conjugates was compared. In 3-hour incubations with either TCVG or DCVG at 1 mM, isolated kidney cells from male rats exhibited 40% and 26% release of lactate dehydrogenase, respectively, while isolated kidney cells from female rats exhibited 18% release with both conjugates. Thus, tetrachloroethylene and its GSH-conjugate TCVG were clearly more acutely cytotoxic to isolated renal cells than trichloroethylene and DCVG, and kidney cells from male rats are significantly more sensitive than kidney cells from female rats to these compounds. Tetrachloroethylene and TCVG also induced toxic effects in mitochondria (i.e. mitochondrial dysfunction, such as a reduced respiratory control ratio and inhibition of state-3 respiration by specific inhibition of several sulfhydryl-containing enzymes) in male rats, and in male and female mice (Lash & Parker, 2001; Lash et al., 2002).

(c) PPRAα activation

(i) Humans

No studies were identified on PPARα activation or peroxisome proliferation in human kidney after exposure to tetrachloroethylene. However, in transactivation studies in vitro, human PPARα was activated by the metabolites dichloroacetate and trichloroacetate, while tetrachloroethylene itself was relatively inactive (Maloney & Waxman, 1999). A few studies have examined PPARα activation by dichloroacetate and trichloroacetate in cultured human liver cells (e.g. Walgren et al., 2000), but the evidence of these effects from studies of human kidney in vivo or in vitro is weak.

(ii) Experimental animals

Two studies addressed peroxisome proliferation in rodent kidney after short-term exposure to tetrachloroethylene (see Table 4.6), but there were no data available concerning activation of the receptor in kidney tissue.

Table 4.6

Renal peroxisome proliferation in rodents exposed to tetrachloroethylene.

Five male F344 rats and five male B6C3F₁ mice were given tetrachloroethylene at a dose of 1000 mg/kg bw per day by gavage in corn oil for 10 days. In exposed rats, cyanide-insensitive palmitoyl-coenzyme A (palmitoyl-coA) oxidation activity was modestly—although not significantly—elevated in the kidney (1.7-fold increase). In mice, the treatment enhanced palmitoyl-coA oxidation activity by 2.3-fold in the kidney. Relative kidney weight was unaffected. A comparison of corn oil with methylcellulose revealed no effect of the gavage vehicle on tetrachloroethylene-induced palmitoyl-coA oxidation. A less-than-additive effect on palmitoyl-coA oxidation was seen when trichloroethylene (1000 mg/kg bw) was administered together with tetrachloroethylene (Goldsworthy & Popp, 1987).

In the second study, male and female F344 rats and B6C3F₁ mice were exposed to tetrachloroethylene by inhalation (400 ppm, 6 hours per day for 14, 21, or 28 days; 200 ppm, 6 hours per day for 28 days), and palmitoyl-coA oxidation activity was measured in liver and kidney. Due to insufficient material, the analysis of the mouse kidney tissues was done on pooled samples. Slight increases in palmitoyl-coA oxidation were observed in the kidney of male mice (maximum increase of 1.6-fold at 21 days, 400 ppm), but no change in female mice. Modest increases were noted in the kidney of male rats at 200 ppm at 28 days (1.3-fold) but not at 400 ppm at 14, 21, or 28 days. In female rat kidney, palmitoyl-coA oxidation activity was elevated (approximately 1.6-fold) at all doses and times. However, peroxisome proliferation was not observed in rat or mouse kidney when analysed by microscopy (Odum et al., 1988).

4.3.2. Liver

(a) Epigenetic effects

(i) Humans

No data were available from studies in humans regarding a role for alteration in DNA methylation in tetrachloroethylene-induced tumorigenesis.

(ii) Experimental animals

No data were available from studies in experimental animals regarding a role for alteration in DNA methylation in tetrachloroethylene-induced tumorigenesis. However, experimental support for hypomethylation of DNA is available from studies in mice exposed to the metabolites trichloroacetate and dichloroacetate.

When female B6C3F₁ mice received an intraperitoneal injection of N-methyl-N-nitrosourea (MNU) as an initiator followed by exposure to trichloroacetate or dichloroacetate in drinking-water, DNA methylation in the resulting hepatocellular adenomas and carcinomas was about half that observed in non-tumour tissue from the same animal or from animals given MNU alone (Tao et al., 1998). Exposure of female B6C3F₁ mice to drinking-water containing trichloroacetate or dichloroacetate for 11 days reduced total liver-DNA methylation by 60% (Tao et al., 1998). In a further study, changes in methylation of the c-jun and c-myc genes, and alterations in gene expression were measured in liver tumours initiated by MNU and promoted by dichloroacetate and trichloroacetate in female B6C3F₁ mice. Hypomethylation and overexpression of these genes were found in liver tumours promoted by dichloroacetate and trichloroacetate (Tao et al., 2000). Subsequently, these investigators reported hypomethylation of a region of the IGF-II gene in liver and tumours from mice initiated with MNU and then exposed to trichloroacetate or dichloroacetate (Tao et al., 2004).

(b) Cytotoxicity and secondary oxidative stress

(i) Humans

A group of 49 workers in the metal-processing industry was exposed to trichloroethylene and tetrachloroethylene at different concentrations. The workers were divided in three groups based on job descriptions, but no exposure assessment was performed. Several markers to assess liver functions were investigated: alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, copper, and zinc. The bromphthaleine test was also performed. Statistically, there were no differences between the values found for exposed and controls, the outcome of the tests all being in the normal range (Szadkowski & Körber, 1969).

A health-surveillance study was conducted among 22 workers exposed to tetrachloroethylene (time-weighted average, 21 ppm; range, 9–38 ppm) in six dry-cleaning shops. Results of behavioural, renal, hepatic, and pulmonary tests on these workers were compared with those obtained for 33 subjects not exposed to organic solvents. No differences were observed in mean serum hepatic enzyme concentrations (Lauwerys et al., 1983) [The Working Group noted the lack of proper statistical analysis].

The hepatic health status of 133 dry-cleaning plant workers (women and men) exposed to tetrachloroethylene and 107 controls was assessed by measuring ALT, AST, fatty acids, prothrombin index, bilirubin and iron in serum, by recording a proteinogram, and by conducting the thymol turbidity test. Among women, no statistically significant differences were found between exposed and controls. Among men, statistically significant differences in values (mean and standard deviation) for aminotransferases were observed. Increased activities of serum enzymes were seen in workers exposed to high concentrations of tetrachloroethylene (Gluszczowa, 1988).

Results were presented of a five-year follow-up of 130 workers exposed to tetrachloroethylene in dry-cleaning shops. The study involved measurement of exposure conditions (personal dosimetry, exposure tests) and clinical investigations (ALT, AST, alkaline phosphatase, GGT, alanine aminopeptidase, cholinesterase) and plasma concentrations of bilirubin, cholesterol and triglycerides. No signs of hepatotoxicity due to exposure to tetrachloroethylene were observed (Müller et al., 1989).

Subjective symptoms and clinical indicators of liver injury were evaluated among 56 dry-cleaning workers (29 men, 27 women) who had been exposed to tetrachloroethylene vapour (20 ppm, 8-hour TWA) for several years. A control group (32 men, 37 women) of similar age recruited from the same factories was not exposed to solvents. There was an exposure-related increase in the prevalence of symptoms such as dizziness, floating sensation, and headache among the exposed workers. In haematological assays and serum biochemistry tests, no significant changes were seen in AST or ALT, alkaline phosphatase or leukocyte alkaline phosphatase, GGT or total bilirubin (Cai et al. (1991).

The isoenzyme pattern of serum GGT was studied in 141 male and female workers in dry-cleaning shops exposed to tetrachloroethylene (8-hour TWA, 11.3 ppm) and in 130 control subjects. None of the workers showed clinical symptoms of liver disease and their enzymatic profiles, including AST, ALT, 5′nucleotidase, alkaline phosphatase, and GGT, were within the normal range. A statistically significant increase in total GGT in serum was found in the exposed subjects, which was due to an increase in one of the two fractions normally present in healthy individuals (GGT-2), and to the appearance and progressive increase in the level of a fraction (GGT-4) considered to be indicative of hepato-biliary impairment. [It should be noted that individuals who had liver enzyme activity above the normal range, and those who had past or current liver disease were not included in this study (Gennari et al., 1992).]

A study was conducted to determine whether subclinical hepatotoxicity is associated with exposure to tetrachloroethylene at concentrations commonly experienced in the workplace, and whether surveillance with serum hepatic transaminase activity underestimates such effects. Included in the study were 29 dry-cleaning operators (8-hour TWA, 16 ppm) and a control group of 29 non-exposed laundry workers. Hepatic parenchymal tissue was scanned by means of ultrasonography; hepatic transaminase activity in serum was also measured. ALT activities of up to 1.5 times the normal limits were found in five out of 27 (19%) dry-cleaning workers compared with one out of 26 (4%) laundry workers. In contrast, ultrasonography revealed a twofold increase in hepatic parenchymal changes in 18 out of 27 dry-cleaning workers (67%), compared with 10 of 26 (39%) laundry workers (Brodkin et al., 1995).

(ii) Experimental animals

Numerous studies in experimental animals, including long-term bioassays, have demonstrated that tetrachloroethylene is hepatotoxic, with the mice being more sensitive than rats (NCI, 1977; Schumann et al., 1980; NTP, 1986; JISA, 1993). Male and female NMRI mice were exposed by whole-body inhalation to various concentrations of tetrachloroethylene (9–3600 ppm) in different experimental designs (continuous or intermittent exposure, from 4 to 120 days). In mice continuously exposed to tetrachloroethylene for 30 days, the increase in plasma butyrylcholinesterase activity became significant at exposure levels > 37 ppm. Compared with controls, the increase was 1.7-fold in female mice and 2.5-fold in male mice after exposure for 120 days to 150 ppm. Under these conditions, the increase in liver weight was 2.3-fold in female mice and 1.9-fold in male mice. The activity of butyrylcholinesterase returned to normal within 30 days after cessation of exposure, but a 10% increase in liver weight remained. No signs of cholestasis were found upon histopathological examination of the liver (Kjellstrand et al., 1984).

Hepatic toxicity was observed in rodents during short- and long-term (lifetime) bioassays with tetrachloroethylene administered by inhalation (NTP, 1986). In a 13-week study, male and female rats and mice were exposed to tetrachloroethylene (0, 100, 200, 400, 800, or 1600 ppm) by inhalation (6 hours per day, 5 days per week). In the group at the highest dose, some rats (males, 4 out of 10; females, 7 out of 10) and some mice (males, 2 out of 10; females, 4 out 10) died before the end of the study. Exposure to tetrachloroethylene (200 ppm and above) increased the incidence of hepatic congestion in male and female rats. In mice of both sexes, liver inflammatory lesions (leukocytic infiltration, centrilobular necrosis, and bile stasis) were observed at 400, 800, or 1600 ppm. Tetrachloroethylene was also administered by inhalation to F344 rats (0, 200, or 400 ppm) or B6C3F₁ mice (0, 100, or 200 ppm) for 103 weeks (6 hours per day, 5 days per week). In male and female mice, in addition to liver tumours (see Section 3), liver degeneration was reported in 2 out of 49, 8 out of 49, and 14 out of 50 males, and in 1 out of 49, 2 out of 50, and 13 out of 50 females in the three groups. Degeneration was characterized by cytoplasmic vacuolization, hepatocellular necrosis, inflammatory cell infiltrates, pigmented cells, oval cell hyperplasia, and regenerative foci. Liver necrosis was observed at increased incidence in males (1 out of 49, 6 out of 49, and 15 out of 50) and in females at 400 ppm (3 out of 48, 5 out of 50, and 9 out of 50). Nuclear inclusions increased in male mice (2 out of 49, 5 out of 49, and 9 out of 50). No dose-related effects on the liver were reported in the rats.

Male Swiss-Cox mice were exposed to tetrachloroethylene by oral gavage (0, 20, 100, 200, 500, 1000, 1500, or 2000 mg/kg bw per day) on 5 days per week for 6 weeks. Liver necrosis, polyploidy in the centrilobular region, and lipid accumulation were evident upon histopathological examination of mice at 200 or 1000 mg/kg bw. Liver:body weight ratios and liver triglycerides were significantly increased at doses ≥ 100 mg/kg bw per day. Enlarged hepatocytes, polyploidy in the centrilobular region, and lipid accumulation were evident upon histopathological examination of mice exposed to 200 or 1000 mg/kg bw. The percentage increase in the liver:body weight ratio was highly correlated with the amount of tetrachloroethylene metabolized (urinary levels of metabolites). Other indices of tetrachloroethylene hepatotoxicity (e.g. increased serum ALT activity) were significantly increased at doses ≥ 500 mg/kg bw (Buben & O’Flaherty, 1985).

An inhalation study by the Japanese Industrial Safety Association (JISA) used male and female Crj/BDF1 mice (exposed at 0, 10, 50, and 250 ppm tetrachloroethylene) and F344/DuCrj rats (exposed at 0, 50, 200, and 600 ppm). Exposure was for 104 weeks and the mice were killed at 110 weeks. In mice, in addition to hepatocellular carcinomas and adenomas (see Section 3), focal liver necrosis was observed in males at doses of 50 ppm and higher. Liver degeneration was noted at 250 ppm in males and females. In male but not female rats, an excess incidence of spongiosis hepatitis was reported at 200 ppm and 600 ppm (JISA, 1993).

Female F344 rats were dosed by oral gavage either once (0, 150, 500, 1500, and 5000 mg/kg bw), or daily for 14 consecutive days (0, 50, 150, 500, 1500 mg/kg bw per day). An increase in the concentration of serum ALT was seen in rats at the highest dose in the 14-day exposure experiment (Berman et al., 1995).

Tetrachloroethylene-associated hepatotoxicity was evaluated after exposure of female Wistar rats at 600 or 2400 mg/kg bw per day via oral gavage in corn oil for 32 days. At the higher dose, the activities of ALT and AST in serum were significantly increased. There was also a significant increase in relative liver weight (Jonker et al., 1996).

The hepatotoxic effect of repeated exposure was investigated in male Swiss Webster mice that were given tetrachloroethylene as three doses (150, 500, or 1000 mg/kg bw) via aqueous gavage, daily for up to 30 days. Tissue injury was monitored regularly during the dosing regimen on days 1, 7, 14, and 30, and over a time course of 24–96 hours after the last dose. Significant increases in serum ALT were observed after a single exposure at all three doses. Higher levels of ALT were also found in the group receiving the highest dose after 7 days, and in all three groups after 14 days of continuous exposure, but no longer after 30 days of exposure, nor in the follow-up samples. Mild to moderate centrilobular degeneration was observed in the liver of mice in the groups receiving the intermediate and highest dose after 1 day of exposure. By 30 days, both groups showed a reduction of tissue damage compared with day 1, as well as evidence of tissue repair, primarily visible as an increase in hepatocellular mitotic figures (Philip et al., 2007).

A limited number of studies focused on tetrachloroethylene-induced hepatic oxidative stress. When tetrachloroethylene was given orally in sesame oil to male and female Swiss mice at 3000 mg/kg bw per day for 15 days, a significant increase in liver weight was seen, as well as degeneration and necrosis of hepatocytes. These changes occurred simultaneously with a decrease in blood glucose, enhanced activity of the enzymes hexokinase, aldolase, and phosphoglucoisomerase, and reduced activities of enzymes involved in gluconeogenesis. Most of these effects were mitigated by concomitant exposure to 2-deoxy-d-glucose or vitamin E (Ebrahim et al., 1996).

In a further study, the potential protective properties of 2-deoxy-d-glucose, vitamin E, and taurine against membrane damage were investigated with a similar treatment protocol. Male albino Swiss mice were exposed to the same doses of tetrachloroethylene as used in the previous study, with the addition of a taurine-exposed group. Membrane-bound Na⁺K⁺-ATPase and Mg²⁺-ATPase activity were significantly decreased (P < 0.001), while Ca²⁺-ATPase activity was increased (P < 0.001) after exposure to tetrachloroethylene alone. These levels remained close to normal in mice exposed to tetrachloroethylene together with 2-deoxy-d-glucose, vitamin E, or taurine. This return to normal levels after exposure to vitamin E and taurine may be due to their activity as an antioxidant, and the ensuing reduction in oxidative stress in exposed cells (Ebrahim et al., 2001).

(c) Cell proliferation

Increased cell proliferation in mice has been reported after exposure to tetrachloroethylene. To study the extent to which tetrachloroethylene alters cell proliferation and apoptosis, several studies have measured hepatocyte proliferation in mice in response to treatment with the metabolite trichloroacetate (Sanchez & Bull, 1990; Dees & Travis, 1994; Pereira, 1996; Stauber & Bull, 1997; DeAngelo et al., 2008). For instance, Dees & Travis (1994) observed relatively small (two- to threefold) but statistically significant increases in [³H]thymidine incorporation in hepatic DNA in mice exposed by gavage for 11 days to trichloroacetate at doses (100–1000 mg/kg bw) that increased the relative liver weight. Increased hepatic DNA labelling was seen at doses lower than those associated with evidence of necrosis, suggesting that trichloroacetate-induced cell proliferation is not due to regenerative hyperplasia.

In the study by Philip et al. (2007) above, a dose-dependent increase in [³H]thymidine incorporation was observed in all dose groups on day 7 of treatment, which was sustained until 14 days in the groups at the intermediated dose and highest dose. A lower level of cell proliferation was evident after 30 days than after 14 days exposure to all three doses. PCNA immunohistochemistry was performed to confirm the findings of S-phase stimulation determined by the [³H]thymidine pulse-labelling study. The immunochemistry results and the pulse-labelling data were consistent (Philip et al., 2007).

(d) PPAR-α activation

Tetrachloroethylene or its metabolites have been shown to induce activation of PPARα or markers of peroxisome proliferation in the liver.

(i) Humans

No studies were available on peroxisome proliferation or the key events in PPARα activation in human liver. However, transactivation studies in vitro have shown that in humans PPARα is activated by trichloroacetate and dichloroacetate, while tetrachloroethylene itself is relatively inactive (Zhou & Waxman, 1998). A limited number of studies focused on PPARα activation by the tetrachloroethylene metabolites dichloroacetate and trichloroacetate in cultured human liver cells. In one of these studies, trichloroacetate and dichloroacetate did not increase palmitoyl-CoA oxidation and caused a decrease in DNA synthesis in human hepatocyte cultures, in contrast to the response seen in rodents (Walgren et al., 2000).

(ii) Experimental animals

Several studies in experimental animals in vivo examined the effect of tetrachloroethylene on peroxisome proliferation or its markers in the liver (Table 4.7).

Table 4.7

Studies of induction of hepatic peroxisome proliferation or its markers in rodents exposed to tetrachloroethylene.

Groups of five male and five female F344 rats and B6C3F₁ mice were exposed by inhalation for 6 hours per day to tetrachloroethylene at 200 ppm for 28 days, or at 400 ppm for 14, 21, or 28 days. In both sexes and in both species, hepatic palmitoyl-coA oxidation activity was increased (mice, up to 3.6-fold; rats, up to 1.3-fold). Hepatic peroxisome proliferation was noted by electron microscopy in all exposed mice, and the proportion of the cytoplasm occupied by peroxisomes was increased. In rats, variable increases in peroxisome volume were noted at 200 ppm, but results lacked statistical significance. Catalase, another peroxisomal enzyme, was unaffected by tetrachloroethylene: male mice exposed at 400 ppm showed only a moderate increase (1.4-fold). Mitochondrial proliferation was observed at 28 days in male mice in the group at 400 ppm. In addition, a time-dependent proliferation of smooth endoplasmic reticulum in the liver of males and females correlated well with centrilobular hypertrophy. Tetrachloroethylene caused centrilobular lipid accumulation in male and female mice. Relative liver weight was increased in male and female mice (Odum et al., 1988).

Five male F344 rats and five male B6C3F₁ mice were given tetrachloroethylene (1000 mg/kg bw) in corn oil by gavage, daily for 10 days. In the rats, palmitoyl-coA oxidation was modestly, although not statistically significantly, elevated in the liver (1.4-fold). In exposed mice, palmitoyl-coA oxidation was increased 4.3-fold in. Relative liver weight was increased in rats and mice. A comparison between corn oil and methylcellulose showed no effect of the gavage vehicle on tetrachloroethylene-induced palmitoyl-coA oxidation. Administration of trichloroethylene (1000 mg/kg bw) together with tetrachloroethylene had a less-than-additive effect on induction of palmitoyl-coA oxidation (Goldsworthy & Popp, 1987).

Kyrklund et al. (1990) exposed male Sprague-Dawley rats to tetrachloroethylene at 320 ppm continuously for 90 days, followed by a 30-day recovery period. Relative liver weight was significantly increased in rats examined at the end of the exposure period. A slight increase in relative liver weight was also observed in the recovered, solvent-treated group.

SV129 PPARα-deficient mice exposed to trichloroacetate at doses up to 2 g/L in drinking-water for 7 days did not show the characteristic induction of acyl-coenzyme A oxidase, palmitoyl-coA oxidase, and CYP4A associated with PPARα activation and peroxisome proliferation in wild-type animals. In addition, the livers from wild-type, but not PPARα-deficient, mice exposed to trichloroacetate at 2 g/L developed centrilobular hepatocyte hypertrophy, although no significant increase in relative liver weight was seen (Laughter et al., 2004).

CYP4A, a marker for PPARα-activation, was transiently increased (only on day 7 of a 30-day treatment) in Swiss Webster mice, and only at the highest of three oral doses (150, 500, 1000 mg/kg bw per day) (Philip et al., 2007). [The Working Group noted that in the NCI cancer bioassay, liver tumours had appeared at doses around 500 mg/kg bw per day (NCI, 1977), at which no increased CYP4A activity was reported. The sensitivity of the Swiss Webster mouse strain relative to that of the B6C3F₁ mice used in the cancer bioassay is unknown.]

(e) Disruption of gap-junctional intercellular communication

The lucifer-yellow scrape-load dye-transfer technique was used to examine the effect of tetrachloroethylene, dichloroacetate, and trichloroacetate on cultures of clone-9 normal rat-liver cells after exposure during 1, 4, 6, 24, 48, and 168 hours. Tetrachloroethylene caused a significant effect at 0.01 mM after 48 hours. Over a 24-hour treatment period the relative efficiencies, expressed as the concentration needed to produce a 50% reduction in intercellular communication, were 0.3 mM for tetrachloroethylene, 3.8 mM for trichloroacetate, and 41 mM for dichloroacetate. The time course of the effect was similar for the three compounds (Benane et al., 1996).

4.3.3. Immune system

(a) Humans

Several recent studies have evaluated the immunotoxicity of exposure to tetrachloroethylene. A small cross-sectional study conducted in the Czech Republic included 21 exposed workers in the dry-cleaning industry and 16 controls from the same plant. Several immunological markers were measured, including α-macroglobulin, phagocyte activity, T lymphocytes, concentrations of the complement proteins C3 and C4, and immunoglobulins. These parameters were compared with laboratory reference values from blood donors and healthy individuals in the same region. Biological monitoring of the workers over an 8-hour working shift showed tetrachloroethylene in exhaled air in the range of 9 to 344 mg/m³ at the end of the shift. Compared with controls, the exposed workers had significantly elevated serum concentrations of the proteins C3 and C4 and higher salivary concentrations of IgA. Compared with reference values from 41 healthy blood donors, the serum concentration of C3 of the exposed workers was higher, while the number of T lymphocytes was reduced (Andrýs et al., 1997).

In terms of sample size and the use of an appropriately matched control group, the strongest study examining immunological and haematological effects of exposure to tetrachloroethylene was that among 40 male dry-cleaning workers who had mean exposure levels up to 140 ppm, and a mean exposure duration of 7 years. Statistically significant decreases in erythrocyte count and haemoglobin levels, and increases in total leukocyte counts and lymphocyte counts were observed in the exposed workers compared with age- and smoking-matched controls. In addition, increases in several other immunological parameters, including T-lymphocyte and natural killer-cell subpopulations, IgE, and interleukin-4 levels were reported. These immunological effects suggest an augmentation of Th2 responsiveness (Emara et al., 2010).

Case–control studies that evaluated the risk of autoimmune disease in relation to exposure to tetrachloroethylene have not suggested that there is a significant association.

The association with exposure to tetrachloroethylene was evaluated in 60 patients who were positive for ANCA (anti-neutrophil cytoplasmic antibody) and 120 age- and sex-matched controls in France (Beaudreuil et al., 2005). Cases included hospital in-patients (admitted in 1990–2000) who were ANCA-positive, and in-patient controls (admitted in 2000–2001) matched to cases by age (± 5 years) and sex. An interviewer-administered questionnaire was used to evaluate occupational exposure to several solvents and other chemicals. The exposure assessment included both qualitative and semiquantitative methods and was assessed by a panel of experts blinded to the disease status of the patients. A total of five ANCA-positive patients were reported to be exposed to tetrachloroethylene; leading to a twofold non-significantly increased risk of ANCA-positivity associated with exposure to tetrachloroethylene.

A case–control study of 205 female patients with undifferentiated connective tissue disease (UCTD) and 2095 population-based controls in the USA evaluated the association between UCTD and exposure to petroleum distillate solvents, including tetrachloroethylene. Exposures to solvents were self-reported in a personal interview, which included an assessment of the number of years each woman had worked with the solvent, whether protective equipment was used, and job activities. The only available risk estimate was for nine exposed cases in dry-cleaning workers; the risk of UCTD in these workers was marginally elevated, but not statistically significant (Lacey et al., 1999).

Two studies of children in Germany have evaluated formation of IgE antibodies to food and allergens and measured the number of cytokine-producing peripheral T-cells in relation to exposure to tetrachloroethylene and other volatile organic compounds. In the first study, serum IgE concentrations were measured in 121 children, while cytokine measurements were available for 28 children. Exposures to tetrachloroethylene and other volatiles were passively monitored in the bedroom of each child for 4 weeks; the median exposure level was reported for tetrachloroethylene to be 2.54 µg/m³. This indoor exposure was not significantly associated with allergic sensitization to egg white or milk, or with cytokine-producing T-cells (Lehmann et al., 2001).

In a study of 22 Hispanic children with asthma living in Los Angeles, USA, symptom diaries were completed for 3 months, while outdoor 24-hour air samples were collected from a central site to assess airborne concentrations of tetrachloroethylene, other volatile organic compounds, and reference air-pollutants. The mean level of exposure to tetrachloroethylene was reported to be 0.51 ppb. More severe asthma symptoms were significantly associated with exposure to tetrachloroethylene, but this association was attenuated and no longer statistically significant after further adjustment for levels of sulfur dioxide and nitrogen dioxide (Delfino et al., 2003a).

(b) Experimental animals

No studies were available on the toxicity of tetrachloroethylene in putative target tissues in the immune system in F344 rats, i.e. bone marrow, spleen, or target cells of mononuclear cell leukeamia. However, in mice the haematopoietic toxicity of tetrachloroethylene has been demonstrated in several studies.

In albino Swiss mice, administration of tetrachloroethylene in sesame oil (3000 mg/kg bw per day, for 15 days) by oral intubation resulted in a significant decrease in haemoglobin, haematocrit (erythrocyte volume fraction), and erythrocyte and platelet counts, and a significant increase in leukocyte counts (Ebrahim et al., 2001). These findings are similar to those observed in studies in humans exposed to tetrachloroethylene (Emara et al., 2010).

Female NMRI mice were given tetrachloroethylene in drinking-water at nominal doses of 0.05 or 0.1 mg/kg bw per day for 7 weeks. The treatment resulted in reversible haemolytic anaemia, and there was evidence from microscopical analyses of splenic involvement. Tetrachloroethylene accumulated in the spleen to a significantly greater extent than in liver, brain, or kidney; levels of tetrachloroethylene in the spleen were 20-fold those in the liver after 7 weeks (Marth, 1987). Tetrachloroethylene was also found in the spleen and fatty tissue of treated mice up to 2 months after the end of the 7 weeks of exposure (Marth et al., 1989).

Female hybrid mice (C57/BL/6 × DBA/2) were exposed to tetrachloroethylene at a concentration of 270 ppm for 6 hours per day, 5 days per week for 11.5 weeks, and at 135 ppm for 6 hours per day for 7.5 weeks, followed by a 3-week exposure-free period. There was a reduction in erythrocyte count, supported by decreases in colony-forming units (CFU) and burst-forming units (BFU) of erythroid cells, and evidence of reticulocytosis. Reversible reductions in the numbers of lymphocytes/monocytes and neutrophils were also observed. The slight depression in number of granulocyte progenitor cells (CFU-C), which persisted after the exposure, could indicate the beginning of disturbance at all levels of progenitor cell (Seidel et al., 1992).

Several leukaemogens (e.g. benzene) inhibit the production of both erythrocytes and various types of leukocyte in blood. A decrease in CFU-Ss has commonly been reported, but this effect is not observed after exposure to tetrachloroethylene. Leukaemogens also cause a decrease in number of several myeloid progenitors in the bone marrow; CFU-E/BFU-E was also reduced by tetrachloroethylene (Seidel et al., 1989a, b). Thus, there is indirect evidence that tetrachloroethylene induces effects associated with leukaemogenesis (NRC, 2010).

Some studies focused on the immunotoxicity of tetrachloroethylene, but their number was too small to establish whether tetrachloroethylene affects immune parameters in a way that would confirm its leukaemia-inducing potential.

Immunosuppression was observed in female B6C3F₁ mice given tetrachloroethylene in drinking-water (maximum concentration, 6.8 ppm) in a mixture of 24 contaminants of groundwater occurring frequently near Superfund sites in the USA (i.e. an uncontrolled or abandoned place where hazardous waste is located; Germolec et al., 1989). Mice exposed to the highest dose of this mixture for 14 or 90 days showed suppression of haematopoietic stem cells and of antigen-induced antibody-forming cells. There were no effects on T-cell function or in numbers of T and B-cells in any exposed group. No changes were evident upon challenge with Listeria monocytogenes or PYB6 tumour cells.

Aranyi et al. (1986) exposed female CD-1 mice to tetrachloroethylene at a concentration of 25 or 50 ppm by inhalation as a single (3 hours) or repeated dose (5 days per week, 3 hours per day). Susceptibility to Streptococcus zooepidemicus aerosol infection and pulmonary bactericidal activity to inhaled Klebsiella pneumoniae were evaluated. A single 3-hour exposure to tetrachloroethylene at 50 ppm significantly increased susceptibility to respiratory infection and mortality after exposure to S. zooepidemicus. In addition, the 3-hour exposure to tetrachloroethylene at 50 ppm was associated with a statistically significant decrease in pulmonary bactericidal activity. No significant differences were observed in mice exposed to tetrachloroethylene at 25 ppm.

4.3.4. Central nervous system

No data were available directly concerning either the metabolites or the mechanisms that may contribute to the induction of rare tumours of the brain (glioma) occurring in rats exposed to tetrachloroethylene (see Section 3). Studies in humans and experimental animals indicate an association of neurobehavioural defects with exposure to tetrachloroethylene (see Bale et al. 2011 for a recent review). The primary neurobehavioural changes observed after exposure to tetrachloroethylene are changes in vision, cognitive deficits, and increased reaction time. The acute effects of tetrachloroethylene appear to have much in common with those of other chlorinated solvents such as trichloroethylene and dichloromethane, as well as toluene, volatile anaesthetics, and alcohols. It is not known how the different neurological effects are induced, but there is information available to help elucidate which areas in the brain and which specific molecular targets may be involved in the ensuing neurotoxicological outcome.

(a) Humans

Data on neurotoxicity in humans were available from controlled experimental chamber studies (Altmann et al., 1990) and epidemiological investigations that used standardized neurobehavioural batteries (Altmann et al., 1995; Echeverria et al., 1995; Spinatonda et al., 1997) or assessment of visual function (Schreiber et al., 2002; Storm et al., 2011), a neurological outcome known to be sensitive to volatile organic compounds. Seven epidemiological studies examined occupational exposure to tetrachloroethylene (Seeber, 1989; Ferroni et al., 1992; Cavalleri et al., 1994; Echeverria et al., 1995; Spinatonda et al., 1997; Gobba et al., 1998; Schreiber et al., 2002), three epidemiological studies examined residential exposure to tetrachloroethylene (Altmann et al., 1995; Schreiber et al., 2002; Storm et al., 2011), and two were experimental chamber studies of acute effects (Hake & Stewart, 1977; Altmann et al., 1990).

Results from the studies of both occupational and residential exposure support an inference of visual deficits after long-term exposure to tetrachloroethylene. Notably, decrements in colour confusion were reported among all workers exposed to a mean TWA of 6 ppm for an average of 8.8 years (Cavalleri et al., 1994).

Studies of acute effects in humans reported increased latencies of up to 3.0 ms in visual evoked potentials (Altmann et al., 1990) and changes in electroencephalograms [magnitude of effect not specified] (Stewart et al., 1970; Hake & Stewart, 1977) at higher exposures ranging from 340 to 680 mg/m³.

Effects on visiospatial memory (increased response times or cognition errors) in humans were also reported in each of the studies that examined this parameter (Seeber, 1989; Echeverria et al., 1994, 1995; Altmann et al., 1995), in occupational and residential settings.

An occupational exposure study (n = 60) (Ferroni et al., 1992) and a residential exposure study (n = 14) (Altmann et al., 1995), with mean exposure levels of 15 and 0.7 ppm, respectively, reported significant increases in simple reaction time of 24 ms (11% increase) and 40 and 51.1 ms (15 and 20% increases, respectively, for two separate measurements) for the exposed subjects. A third study reported better performance on simple reaction time in 21 exposed workers (mean TWA, 21 ppm) compared with controls when measured before a work shift, but not when measured after work (Lauwerys et al., 1983).

(b) Experimental animals

Mechanistic neuropathological studies have been conducted in animal models (rats, mice, gerbils) to determine how tetrachloroethylene may give rise to the neurological effects observed. Changes in fatty-acid composition of the brain after exposure to tetrachloroethylene at 320 ppm for 30 or 90 days have been reported, and some of these changes persisted for up to 30 days after cessation of exposure (Kyrklund et al., 1988, 1990). Studies that examined the entire brain of animals reported reductions in astroglial proteins (GFAP and S-100), decreased brain RNA content, and decreased levels of glutamine, threonine, and serine (Savolainen et al., 1977; Honma et al., 1980a, b; Kyrklund et al., 1984, 1987, 1988, 1990; Rosengren et al., 1986; Wang et al., 1993). Brain regions examined after exposure to tetrachloroethylene included the frontal cortex, the hippocampus, the striatum, and the cerebellum. Notable changes included decreased DNA content in the frontal cortex after continuous exposure at 600 ppm for 4 weeks in rats (Wang et al., 1993), or exposure at 60 ppm for 3 months in Mongolian gerbils (Karlsson et al., 1987). Decreased levels of taurine were noted in the cerebellum and hippocampus after exposure to tetrachloroethylene at 120 ppm for 12 months in Mongolian gerbils, but there were no changes in levels or uptake of γ-aminobutyric acid (GABA) (Briving et al., 1986).

Reduced concentrations of acetylcholine were noted in the striatum of male rats exposed to tetrachloroethylene at 800 ppm for 1 month (Honma et al., 1980a, b).

Voltage- and ligand-gated ion channels have been implicated in many neurological functions and have been studied as potential neurological targets for tetrachloroethylene and structurally related chlorinated solvents (e.g. trichloroethylene, 1,1,1-trichloroethane, dichloromethane). Tetrachloroethylene has been shown to perturb voltage-sensitive calcium-channel function in nerve growth factor-differentiated pheochromocytoma cells (Shafer et al., 2005) and to block various acetylcholine-induced currents in human neuronal nicotinic acetylcholine receptors by 40–60% (Bale et al., 2005). On the basis of the structural similarity of tetrachloroethylene and other chlorinated solvents, as well as similar neurobehavioural and mechanistic findings, it is likely that tetrachloroethylene also interacts with the other molecular targets. This solvent class, in particular trichloroethylene, has been shown to interact with ion channels such as the GABA_A and glycine receptors (Beckstead et al., 2000; Krasowski & Harrison, 2000; Lopreato et al., 2003). In addition, this class of solvents block the sodium-channel (Shrivastav et al., 1976) and the voltage-sensitive calcium-channel function (Shafer et al., 2005) when the membrane is held at or near the resting membrane potential. Overall, these solvents appear to potentiate the function of inhibitory receptors and inhibit the function of excitatory receptors (see Bowen et al. (2006) and Bushnell et al. (2007) for reviews).

Evidence from the available studies in humans and experimental animals indicated that long-term exposure to tetrachloroethylene can result in decrements in colour vision, visuospatial memory, and possibly other aspects of cognition and neuropsychological function, including reaction time.

5. Summary of Data Reported

6. Evaluation

References

• Abrahamsson K, Ekdahl A, Collén J, Pedersén M. Marine algae- a source of trichloroethylene and perchloroethylene. Limnol Oceanogr. 1995;40:1321–1326. [CrossRef]
• Abundo ML, Almaguer D, Driscoll R (1994). NIOSH Health Hazard Evaluation Report, Electrode Corp., Chadon, Ohio, HETA 93-1133-2425. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Adgate JL, Eberly LE, Stroebel C, et al. Personal, indoor, and outdoor VOC exposures in a probability sample of children. J Expo Anal Environ Epidemiol. 2004;14 Suppl 1:S4–S13. [PubMed: 15118740] [CrossRef]
• Aggazzotti G, Fantuzzi G, Predieri G, et al. Indoor exposure to perchloroethylene (PCE) in individuals living with dry-cleaning workers. Sci Total Environ. 1994;156:133–137. [PubMed: 7992032] [CrossRef]
• Ahrenholz SH, Anderson KE (1982). NIOSH Health Hazard Evaluation Report, Industrial and Automotive Fasteners Inc., Royal Oak, MI. HETA 82-037-1120. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Altmann L, Böttger A, Wiegand H. Neurophysiological and psychophysical measurements reveal effects of acute low-level organic solvent exposure in humans. Int Arch Occup Environ Health. 1990;62:493–499. [PubMed: 2289821] [CrossRef]
• Altmann L, Neuhann HF, Krämer U, et al. Neurobehavioral and neurophysiological outcome of chronic low-level tetrachloroethene exposure measured in neighborhoods of dry cleaning shops. Environ Res. 1995;69:83–89. [PubMed: 8608774] [CrossRef]
• ACGIH; American Conference of Governmental Industrial Hygienists (2002). TLVs and BEIs. Cincinnati, OH, USA: ACGIH Worldwide. Available online at: http://www.acgih.org/
• Andersen A, Barlow L, Engeland A, et al. Work-related cancer in the Nordic countries. Scand J Work Environ Health. 1999;25 Suppl 2:1–116. [PubMed: 10507118]
• Anderson PM, Schultze MO. Cleavage of S-(1,2-dichlorovinyl)-L-cysteine by an enzyme of bovine origin. Arch Biochem Biophys. 1965;111:593–602. [PubMed: 5862209] [CrossRef]
• Andrýs C, Hanovcová I, Chýlková V, et al. Immunological monitoring of dry-cleaning shop workers–exposure to tetrachloroethylene. Cent Eur J Public Health. 1997;5:136–142. [PubMed: 9386901]
• Anon. 1991A close look at dry-cleaning shops. [in French] Manuel tech Nettoyeur Sec 111: 4–11.
• Anttila A, Pukkala E, Sallmén M, et al. Cancer incidence among Finnish workers exposed to halogenated hydrocarbons. J Occup Environ Med. 1995;37:797–806. a. [PubMed: 7552463] [CrossRef]
• Anttila A, Riala R, Pukkala E et al. (1995b). Occupational exposure to solvents and risk of cancer. Final report. Helsinki, Finland: The Finnish Working Environment Fund, pp. 1–74.
• Aranyi C, O’Shea WJ, Graham JA, Miller FJ. The effects of inhalation of organic chemical air contaminants on murine lung host defenses. Fundam Appl Toxicol. 1986;6:713–720. [PubMed: 3519345] [CrossRef]
• Asal NR, Geyer JR, Risser DR, et al. Risk factors in renal cell carcinoma. II. Medical history, occupation, multivariate analysis, and conclusions. Cancer Detect Prev. 1988;13:263–279. [PubMed: 3266567]
• Aschengrau A, Ozonoff D, Paulu C, et al. Cancer risk and tetrachloroethylene-contaminated drinking water in Massachusetts. Arch Environ Health. 1993;48:284–292. [PubMed: 8215591] [CrossRef]
• Aschengrau A, Paulu C, Ozonoff D. Tetrachloroethylene-contaminated drinking water and the risk of breast cancer. Environ Health Perspect. 1998;106 Suppl 4:947–953. [PMC free article: PMC1533339] [PubMed: 9703477]
• Aschengrau A, Rogers S, Ozonoff D. Perchloroethylene-contaminated drinking water and the risk of breast cancer: additional results from Cape Cod, Massachusetts, USA. Environ Health Perspect. 2003;111:167–173. [PMC free article: PMC1241345] [PubMed: 12573900] [CrossRef]
• Ashley DL, Bonin MA, Cardinali FL, et al. Determining volatile organic compounds in human blood from a large sample population by using purge and trap gas chromatography/mass spectrometry. Anal Chem. 1992;64:1021–1029. [PubMed: 1590585] [CrossRef]
• Ashley DL, Bonin MA, Cardinali FL, et al. Blood concentrations of volatile organic compounds in a nonoccupationally exposed US population and in groups with suspected exposure. Clin Chem. 1994;40:1401–1404. [PubMed: 8013127]
• ATSDR (1997a). Toxicological Profile for Trichloroethylene (update). Atlanta, GA: Agency for Toxic Substances and Disease Registry, US Department of Health and Human Services, Public Health Service.
• ATSDR; Agency for Toxic Substances and Disease Registry (1997b). Toxicological Profile for Tetrachloroethylene. Atlanta, GA, USA: Agency for Toxic Substances and Disease Registry, US Department of Health and Human Services, Public Health Service, pp. 1–318. Available online at: http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=265&tid=48. Accessed 23 October 2013.
• ATSDR; Agency for Toxic Substances and Disease Registry (2006). Health Consultation: Health Statistics Review: Cancer and Birth Outcome Analysis: Endicott area investigation: Endicott area, Town of Union, Broome County, New York. Atlanta, GA, USA: US Department of Health and Humans Services, pp. 86. Available at: http://www.atsdr.cdc.gov/HAC/pha/EndicottAreaInvestigation/EndicottHealthStatsReviewHC052606.pdf. Accessed 23 October 2013.
• ATSDR; Agency for Toxic Substances and Disease Registry (2008). Health Consultation: Health Statistics Review Follow-up: Cancer and Birth Outcome Analysis: Endicott area investigation, Endicott area, Town of Union, Broome County, New York. Atlanta, GA, USA: US Department of Health and Human Services, pp. 60. Available at: http://www.atsdr.cdc.gov/hac/pha//EndicottAreaInvestigationFollowUp/EndicottAreaHC051508.pdf. Accessed 23 October 2013.
• Azimi Pirsaraei SR, Khavanin A, Asilian H, Soleimanian A. Occupational exposure to perchloroethylene in dry-cleaning shops in Tehran, Iran. Ind Health. 2009;47:155–159. [PubMed: 19367044] [CrossRef]
• Bagnell PC, Ellenberger HA. Obstructive jaundice due to a chlorinated hydrocarbon in breast milk. Can Med Assoc J. 1977;117:1047–1048. [PMC free article: PMC1880184] [PubMed: 912629]
• Bale AS, Barone S Jr, Scott CS, Cooper GS. A review of potential neurotoxic mechanisms among three chlorinated organic solvents. Toxicol Appl Pharmacol. 2011;255:113–126. [PubMed: 21609728] [CrossRef]
• Bale AS, Meacham CA, Benignus VA, et al. Volatile organic compounds inhibit human and rat neuronal nicotinic acetylcholine receptors expressed in Xenopus oocytes. Toxicol Appl Pharmacol. 2005;205:77–88. [PubMed: 15885267] [CrossRef]
• Bartels MJ. Quantitation of the tetrachloroethylene metabolite N-acetyl-S-(trichlorovinyl)cysteine in rat urine via negative ion chemical ionization gas chromatography/tandem mass spectrometry. Biol Mass Spectrom. 1994;23:689–694. [PubMed: 7811758] [CrossRef]
• Bartsch H, Malaveille C, Barbin A, Planche G. Mutagenic and alkylating metabolites of halo-ethylenes, chlorobutadienes and dichlorobutenes produced by rodent or human liver tissues. Evidence for oxirane formation by P450-linked microsomal mono-oxygenases. Arch Toxicol. 1979;41:249–277. [PubMed: 373707] [CrossRef]
• Beaudreuil S, Lasfargues G, Lauériere L, et al. Occupational exposure in ANCA-positive patients: a case-control study. Kidney Int. 2005;67:1961–1966. [PubMed: 15840044] [CrossRef]
• Beckstead MJ, Weiner JL, Eger EI 2nd, et al. Glycine and gamma-aminobutyric acid(A) receptor function is enhanced by inhaled drugs of abuse. Mol Pharmacol. 2000;57:1199–1205. [PubMed: 10825391]
• Begerow J, Jermann E, Keles T, et al. Internal and external tetrachloroethene exposure of persons living in differently polluted areas of Northrhine-Westphalia (Germany). Zentralbl Hyg Umweltmed. 1996;198:394–406. [PubMed: 9353538]
• Beliles RP, Brusick DJ, Mecler FJ (1980). Teratogenic-mutagenic risk of workplace contaminants: trichloroethylene, perchloroethylene, and carbon disulfide. (210-77-0047) Cincinnati, OH: National Institute for Occupation Safety and Health.
• Benane SG, Blackman CF, House DE. Effect of perchloroethylene and its metabolites on intercellular communication in clone 9 rat liver cells. J Toxicol Environ Health. 1996;48:427–437. [PubMed: 8751833] [CrossRef]
• Bergamaschi E, Mutti A, Bocchi MC, et al. Rat model of perchloroethylene-induced renal dysfunctions. Environ Res. 1992;59:427–439. [PubMed: 1281447] [CrossRef]
• Berman E, Schlicht M, Moser VC, MacPhail RC. A multidisciplinary approach to toxicological screening: I. Systemic toxicity. J Toxicol Environ Health. 1995;45:127–143. [PubMed: 7783250] [CrossRef]
• Bhattacharya RK, Schultze MO. Enzymes from bovine and turkey kidneys which cleave S-(1,2-dichlorovinyl)-L-cysteine. Comp Biochem Physiol. 1967;22:723–735. [PubMed: 6053640] [CrossRef]
• Bi E, Liu Y, He J, et al. Screening of emerging volatile organic contaminants in shallow groundwater in east China. Ground Water Monit Remediat. 2012;32:53–58. [CrossRef]
• Billionnet C, Gay E, Kirchner S, et al. Quantitative assessments of indoor air pollution and respiratory health in a population-based sample of French dwellings. Environ Res. 2011;111:425–434. [PubMed: 21397225] [CrossRef]
• Birner G, Bernauer U, Werner M, Dekant W. Biotransformation, excretion and nephrotoxicity of haloalkene-derived cysteine S-conjugates. Arch Toxicol. 1997;72:1–8. [PubMed: 9458184] [CrossRef]
• Birner G, Richling C, Henschler D, et al. Metabolism of tetrachloroethene in rats: identification of N epsilon-(dichloroacetyl)-L-lysine and N epsilon-(trichloroacetyl)-L-lysine as protein adducts. Chem Res Toxicol. 1994;7:724–732. [PubMed: 7696525] [CrossRef]
• Birner G, Rutkowska A, Dekant W. N-acetyl-S-(1,2,2-trichlorovinyl)-L-cysteine and 2,2,2-trichloroethanol: two novel metabolites of tetrachloroethene in humans after occupational exposure. Drug Metab Dispos. 1996;24:41–48. [PubMed: 8825189]
• Blair A, Decoufle P, Grauman D. Causes of death among laundry and dry-cleaning workers. Am J Public Health. 1979;69:508–511. [PMC free article: PMC1619137] [PubMed: 434285] [CrossRef]
• Blair A, Petralia SA, Stewart PA. Extended mortality follow-up of a cohort of dry-cleaners. Ann Epidemiol. 2003;13:50–56. [PubMed: 12547485] [CrossRef]
• Blair A, Stewart PA, Tolbert PE, et al. Cancer and other causes of death among a cohort of dry-cleaners. Br J Ind Med. 1990;47:162–168. [PMC free article: PMC1035126] [PubMed: 2328223]
• Bogen KT, Colston BW Jr, Machicao LK. Dermal absorption of dilute aqueous chloroform, trichloroethylene, and tetrachloroethylene in hairless guinea pigs. Fundam Appl Toxicol. 1992;18:30–39. [PubMed: 1601207] [CrossRef]
• Boice JD Jr, Marano DE, Fryzek JP, et al. Mortality among aircraft manufacturing workers. Occup Environ Med. 1999;56:581–597. [PMC free article: PMC1757791] [PubMed: 10615290] [CrossRef]
• Boillat MA, Berode M, Droz PO. Surveillance of workers exposed to tetrachloroethylene or styrene. Soz Präventivmed. 1986;31:260–262. [PubMed: 3765881] [CrossRef]
• Bois FY, Gelman A, Jiang J, et al. Population toxicokinetics of tetrachloroethylene. Arch Toxicol. 1996;70:347–355. [PubMed: 8975633] [CrossRef]
• Bond GG, McLaren EA, Sabel FL, et al. Liver and biliary tract cancer among chemical workers. Am J Ind Med. 1990;18:19–24. [PubMed: 2378367]
• Boutonnet JC, De Rooij C, Garny V, et al. Euro Chlor risk assessment for the marine environment OSPARCOM region: North sea-trichloroethylene. Environ Monit Assess. 1998;53:467–487. [CrossRef]
• Bowen SE, Batis JC, Paez-Martinez N, Cruz SL. The last decade of solvent research in animal models of abuse: mechanistic and behavioral studies. Neurotoxicol Teratol. 2006;28:636–647. [PubMed: 17064879] [CrossRef]
• Briving C, Jacobson I, Hamberger A, et al. Chronic effects of perchloroethylene and trichloroethylene on the gerbil brain amino acids and glutathione. Neurotoxicology. 1986;7:101–108. [PubMed: 2872637]
• Brodkin CA, Daniell W, Checkoway H, et al. Hepatic ultrasonic changes in workers exposed to perchloroethylene. Occup Environ Med. 1995;52:679–685. [PMC free article: PMC1128334] [PubMed: 7489059] [CrossRef]
• Bronzetti G, Bauer C, Corsi C, et al. Genetic and biochemical studies on perchloroethylene ‘in vitro’ and ‘in vivo’. Mutat Res. 1983;116:323–331. [PubMed: 6339899] [CrossRef]
• Brown DP, Kaplan SD. Retrospective cohort mortality study of dry-cleaner workers using perchloroethylene. J Occup Med. 1987;29:535–541. [PubMed: 3612328]
• Brownson RC, Alavanja MC, Chang JC. Occupational risk factors for lung cancer among nonsmoking women: a case-control study in Missouri (United States). Cancer Causes Control. 1993;4:449–454. [PubMed: 8218877] [CrossRef]
• Buben JA, O’Flaherty EJ. Delineation of the role of metabolism in the hepatotoxicity of trichloroethylene and perchloroethylene: a dose-effect study. Toxicol Appl Pharmacol. 1985;78:105–122. [PubMed: 2994252] [CrossRef]
• Buist SC, Klaassen CD. Rat and mouse differences in gender-predominant expression of organic anion transporter (Oat1–3; Slc22a6–8) mRNA levels. Drug Metab Dispos. 2004;32:620–625. [PubMed: 15155553] [CrossRef]
• Burgess WA (1981). Recognition of Health Hazards in Industry. A Review of Materials and Processes. New York, NY, USA: John Wiley & Sons, pp. 20–32.
• Burns PB, Swanson GM. Risk of urinary bladder cancer among blacks and whites: the role of cigarette use and occupation. Cancer Causes Control. 1991;2:371–379. [PubMed: 1764561] [CrossRef]
• Burr GA, Todd W (1986). NIOSH Health Hazard Evaluation Report, Dutch Girl Cleaners, Springdale, Ohio. HETA 86-005-1679. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Burroughs GE (1980). NIOSH Health Hazard Evaluation Report, Protective Coatings Corporation, Fort Wayne, IN. HETA 79-96-729. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Burton DT, Dilorenzo JL, Shedd TR, Wrobel JG. Aquatic hazard assessment of a contaminated surficial aquifer discharge into the Bush river, Maryland (U.S.A.). Water Air Soil Pollut. 2002;139:159–182. [CrossRef]
• Bushnell PJ, Oshiro WM, Samsam TE, et al. A dosimetric analysis of the acute behavioral effects of inhaled toluene in rats. Toxicol Sci. 2007;99:181–189. [PubMed: 17548890] [CrossRef]
• Cai SX, Huang MY, Chen Z, et al. Subjective symptom increase among dry-cleaning workers exposed to tetrachloroethylene vapor. Ind Health. 1991;29:111–121. [PubMed: 1765547] [CrossRef]
• California EPA (2008). Fact Sheet, Dry-cleaning - Alternative Solvents: Health and Environmental Impacts. Available online at: http://www.arb.ca.gov/toxics/dryclean/alternativesolvts_e.pdf. Accessed 22 October 2013.
• Callen DF, Wolf CR, Philpot RM. Cytochrome P-450 mediated genetic activity and cytotoxicity of seven halogenated aliphatic hydrocarbons in Saccharomyces cerevisiae. Mutat Res. 1980;77:55–63. [PubMed: 6767185] [CrossRef]
• Calvert GM, Ruder AM, Petersen MR. Mortality and end-stage renal disease incidence among dry cleaning workers. Occup Environ Med. 2011;68:709–716. [PubMed: 21172794] [CrossRef]
• Carpenter SP, Lasker JM, Raucy JL. Expression, induction, and catalytic activity of the ethanol-inducible cytochrome P450 (CYP2E1) in human fetal liver and hepatocytes. Mol Pharmacol. 1996;49:260–268. [PubMed: 8632758]
• Cashman JR, Zhang J. Human flavin-containing monooxygenases. Annu Rev Pharmacol Toxicol. 2006;46:65–100. [PubMed: 16402899] [CrossRef]
• Cavalleri A, Gobba F, Paltrinieri M, et al. Perchloroethylene exposure can induce colour vision loss. Neurosci Lett. 1994;179:162–166. [PubMed: 7845613] [CrossRef]
• CDC (2013). Fourth National Report on Human Exposure to Environmental Chemicals. US Department of Health and Human Services, Center for Disease and Control and Prevention.
• Cederberg H, Henriksson J, Binderup ML. DNA damage detected by the alkaline comet assay in the liver of mice after oral administration of tetrachloroethylene. Mutagenesis. 2010;25:133–138. [PubMed: 19892777] [CrossRef]
• Center for Chemical Hazard Assessment (1985). Monographs on Human Exposure to Chemicals in the Workplace: Tetrachloroethylene. Bethesda, MD, USA: United States National Cancer Institute (NIOSH Report No. 00167179; SCR TR 84-629)
• Charbonneau M, Short BG, Lock EA (1987). Mechanism of petroleum induced sex-specific protein droplet nephropathy and renal cell proliferation in Fischer-344 rats: Relevance to humans. Columbia, MO: University of Missouri.
• Chiappini L, Delery L, Leoz E, et al. A first French assessment of population exposure to tetrachloroethylene from small dry-cleaning facilities. Indoor Air. 2009;19:226–233. [PubMed: 19298226] [CrossRef]
• Chien Y-C (1997). The influences of exposure pattern and duration on elimination kinetics and exposure assessment of tetrachloroethylene in humans [PhD thesis]. New Brunswick, NJ: Rutgers University.
• Chiu WA, Ginsberg GL. Development and evaluation of a harmonized physiologically based pharmacokinetic (PBPK) model for perchloroethylene toxicokinetics in mice, rats, and humans. Toxicol Appl Pharmacol. 2011;253:203–234. [PubMed: 21466818] [CrossRef]
• Chiu WA, Micallef S, Monster AC, Bois FY. Toxicokinetics of inhaled trichloroethylene and tetrachloroethylene in humans at 1 ppm: empirical results and comparisons with previous studies. Toxicol Sci. 2007;95:23–36. [PubMed: 17032701] [CrossRef]
• Christensen KY, Vizcaya D, Richardson H, et al. Risk of selected cancers due to occupational exposure to chlorinated solvents in a case-control study in Montreal. J Occup Environ Med. 2013;55:198–208. [PubMed: 23147555] [CrossRef]
• Chrostek WJ, Levine MJ (1981). NIOSH Health Hazard Evaluation Report, Bechtel Power Corp., Berwick, PA. HETA 80-154-1027. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Class Th, Ballschmiter K. Chemistry of organic traces in air VI: Distribution of chlorinated C1 − C4 hydrocarbons in air over the northern and southern Atlantic Ocean. Chemosphere. 1986;15:413–427. [CrossRef]
• Clayton CA, Pellizzari ED, Whitmore RW, et al. National Human Exposure Assessment Survey (NHEXAS): distributions and associations of lead, arsenic and volatile organic compounds in EPA region 5. J Expo Anal Environ Epidemiol. 1999;9:381–392. [PubMed: 10554141] [CrossRef]
• Clewell HJ, Gentry PR, Covington TR, et al. Evaluation of the potential impact of age- and gender-specific pharmacokinetic differences on tissue dosimetry. Toxicol Sci. 2004;79:381–393. [PubMed: 15056818] [CrossRef]
• Cohn P, Klotz J, Bove F, et al. Drinking Water Contamination and the Incidence of Leukemia and Non-Hodgkin’s Lymphoma. Environ Health Perspect. 1994;102:556–561. [PMC free article: PMC1569761] [PubMed: 9679115] [CrossRef]
• Coler HR, Rossmiller HR. Tetrachlorethylene exposure in a small industry. AMA Arch Ind Hyg Occup Med. 1953;8:227–233. [PubMed: 13079324]
• Colt JS, Karagas MR, Schwenn M, et al. Occupation and bladder cancer in a population-based case-control study in Northern New England. Occup Environ Med. 2011;68:239–249. [PMC free article: PMC3010477] [PubMed: 20864470] [CrossRef]
• Colucci DF, Buyske DA. The biotransformation of a sulfonamide to a mercaptan and to mercapturic acid and glucuronide conjugates. Biochem Pharmacol. 1965;14:457–466. [PubMed: 14322970] [CrossRef]
• Connor TH, Theiss JC, Hanna HA, et al. Genotoxicity of organic chemicals frequently found in the air of mobile homes. Toxicol Lett. 1985;25:33–40. [PubMed: 3887653] [CrossRef]
• Cook CK, Parker M (1994). NIOSH Health Hazard Evaluation Report, Geneva Rubber Co., Geneva, Ohio, HETA 91-0377-2383. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Cooper AJ, Krasnikov BF, Niatsetskaya ZV, et al. Cysteine S-conjugate β-lyases: important roles in the metabolism of naturally occurring sulfur and selenium-containing compounds, xenobiotics and anticancer agents. Amino Acids. 2011;41:7–27. [PMC free article: PMC2898922] [PubMed: 20306345] [CrossRef]
• Cooper AJL, Pinto JT. Cysteine S-conjugate beta-lyases. Amino Acids. 2006;30:1–15. [PubMed: 16463021] [CrossRef]
• Costa AK, Ivanetich KM. Tetrachloroethylene metabolism by the hepatic microsomal cytochrome P-450 system. Biochem Pharmacol. 1980;29:2863–2869. [PubMed: 7437086] [CrossRef]
• Costa AK, Ivanetich KM. Chlorinated ethylenes: their metabolism and effect on DNA repair in rat hepatocytes. Carcinogenesis. 1984;5:1629–1636. [PubMed: 6499114] [CrossRef]
• Costantini AS, Benvenuti A, Vineis P, et al. Risk of leukemia and multiple myeloma associated with exposure to benzene and other organic solvents: evidence from the Italian Multicenter Case-control study. Am J Ind Med. 2008;51:803–811. [PubMed: 18651579] [CrossRef]
• Costantini AS, Miligi L, Kriebel D, et al. A multicenter case-control study in Italy on hematolymphopoietic neoplasms and occupation. Epidemiology. 2001;12:78–87. [PubMed: 11138825] [CrossRef]
• Costello RJ (1979). NIOSH Health Hazard Evaluation Report, Western Electric Co., Denver, CO. HETA 78-111-588. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Coyle YM, Hynan LS, Euhus DM, Minhajuddin AT. An ecological study of the association of environmental chemicals on breast cancer incidence in Texas. Breast Cancer Res Treat. 2005;92:107–114. [PubMed: 15986119] [CrossRef]
• Crowley RC, Ford CB, Stem AC. A study of perchloroethylene degreasers. J Ind Hyg Toxicol. 1945;27:140–144.
• Cummings BS, Lasker JM, Lash LH. Expression of glutathione-dependent enzymes and cytochrome P450s in freshly isolated and primary cultures of proximal tubular cells from human kidney. J Pharmacol Exp Ther. 2000;293:677–685. [PubMed: 10773044]
• Cummings BS, Parker JC, Lash LH. Cytochrome p450-dependent metabolism of trichloroethylene in rat kidney. Toxicol Sci. 2001;60:11–19. [PubMed: 11222868] [CrossRef]
• Cummings BS, Zangar RC, Novak RF, Lash LH. Cellular distribution of cytochromes P-450 in the rat kidney. Drug Metab Dispos. 1999;27:542–548. [PubMed: 10101150]
• Dallas CE, Chen XM, Muralidhara S, et al. Use of tissue disposition data from rats and dogs to determine species differences in input parameters for a physiological model for perchloroethylene. Environ Res. 1994;67:54–67. a. [PubMed: 7925194] [CrossRef]
• Dallas CE, Chen XM, Muralidhara S, et al. Physiologically based pharmacokinetic model useful in prediction of the influence of species, dose, and exposure route on perchloroethylene pharmacokinetics. J Toxicol Environ Health. 1995;44:301–317. [PubMed: 7897693] [CrossRef]
• Dallas CE, Chen XM, O’Barr K, et al. Development of a physiologically based pharmacokinetic model for perchloroethylene using tissue concentration-time data. Toxicol Appl Pharmacol. 1994;128:50–59. b. [PubMed: 8079354] [CrossRef]
• Daniels W, Kramkowski R (1986). NIOSH Health Hazard Evaluation Report, Summit Finishing Co., Inc., Mooresville, IN. HETA 85-083-1705. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Davezies P, Briant V, Bergeret A, et al. Study of working conditions in the dry-cleaning business. Arch Mal Prof. 1983;44:159–165. [in French]
• DeAngelo AB, Daniel FB, Wong DM, George MH. The induction of hepatocellular neoplasia by trichloroacetic acid administered in the drinking water of the male B6C3F1 mouse. J Toxicol Environ Health A. 2008;71:1056–1068. [PubMed: 18569617] [CrossRef]
• Dees C, Travis C. Trichloroacetate stimulation of liver DNA synthesis in male and female mice. Toxicol Lett. 1994;70:343–355. [PubMed: 8284802] [CrossRef]
• Dekant W, Berthold K, Vamvakas S, et al. Thioacylating intermediates as metabolites of S-(1,2-dichlorovinyl)-L-cysteine and S-(1,2,2-trichlorovinyl)-L-cysteine formed by cysteine conjugate beta-lyase. Chem Res Toxicol. 1988;1:175–178. [PubMed: 2979728] [CrossRef]
• Dekant W, Birner G, Werner M, Parker J. Glutathione conjugation of perchloroethene in subcellular fractions from rodent and human liver and kidney. Chem Biol Interact. 1998;116:31–43. [PubMed: 9877199] [CrossRef]
• Dekant W, Martens G, Vamvakas S, et al. Bioactivation of tetrachloroethylene. Role of glutathione S-transferase-catalyzed conjugation versus cytochrome P-450-dependent phospholipid alkylation. Drug Metab Dispos. 1987;15:702–709. [PubMed: 2891489]
• Dekant W, Metzler M, Henschler D. Identification of S-1,2,2-trichlorovinyl-N-acetylcysteine as a urinary metabolite of tetrachloroethylene: bioactivation through glutathione conjugation as a possible explanation of its nephrocarcinogenicity. J Biochem Toxicol. 1986;1:57–72. a. [PubMed: 3271876] [CrossRef]
• Dekant W, Vamvakas S, Berthold K, et al. Bacterial beta-lyase mediated cleavage and mutagenicity of cysteine conjugates derived from the nephrocarcinogenic alkenes trichloroethylene, tetrachloroethylene and hexachlorobutadiene. Chem Biol Interact. 1986;60:31–45. b. [PubMed: 3536138] [CrossRef]
• Delahunt B, Bethwaite PB, Nacey JN. Occupational risk for renal cell carcinoma. A case-control study based on the New Zealand Cancer Registry. Br J Urol. 1995;75:578–582. [PubMed: 7613791] [CrossRef]
• Delfino RJ, Gong H Jr, Linn WS, et al. Asthma symptoms in Hispanic children and daily ambient exposures to toxic and criteria air pollutants. Environ Health Perspect. 2003;111:647–656. a. [PMC free article: PMC1241459] [PubMed: 12676630] [CrossRef]
• Delfino RJ, Gong H Jr, Linn WS, et al. Respiratory symptoms and peak expiratory flow in children with asthma in relation to volatile organic compounds in exhaled breath and ambient air. J Expo Anal Environ Epidemiol. 2003;13:348–363. b. [PubMed: 12973363] [CrossRef]
• DeMarini DM, Perry E, Shelton ML. Dichloroacetic acid and related compounds: induction of prophage in E. coli and mutagenicity and mutation spectra in Salmonella TA100. Mutagenesis. 1994;9:429–437. [PubMed: 7837977] [CrossRef]
• Demeestere K, Dewulf J, De Witte B, Van Langenhove H. Sample preparation for the analysis of volatile organic compounds in air and water matrices. J Chromatogr A. 2007;1153:130–144. [PubMed: 17258752] [CrossRef]
• Doherty AT, Ellard S, Parry EM, Parry JM. An investigation into the activation and deactivation of chlorinated hydrocarbons to genotoxins in metabolically competent human cells. Mutagenesis. 1996;11:247–274. [PubMed: 8671747] [CrossRef]
• Doherty RE. A history of the production and use of carbon tetrachloride, tetrachloroethylene, trichloroethylene and 1,1,1-trichloroethane in the United States, Part 1 Historical background: carbon tetrachloride and tetrachloroethylene. J Environmental Forensics, 2000;1:69–81. a. [CrossRef]
• Doherty RE. A history of the production and use of carbon tetrachloride, tetrachloroethylene, trichloroethylene and 1,1,1-trichloroethane in the United States, Part 2 Trichloroethylene and 1,1,1-trichloroethane. J Environmental Forensics. 2000;1:82–93. b.
• Dosemeci M, Cocco P, Chow WH. Gender differences in risk of renal cell carcinoma and occupational exposures to chlorinated aliphatic hydrocarbons. Am J Ind Med. 1999;36:54–59. [PubMed: 10361587] [CrossRef]
• Dreessen B, Westphal G, Bünger J, et al. Mutagenicity of the glutathione and cysteine S-conjugates of the haloalkenes 1,1,2-trichloro-3,3,3-trifluoro-1-propene and trichlorofluoroethene in the Ames test in comparison with the tetrachloroethene-analogues. Mutat Res. 2003;539:157–166. [PubMed: 12948824] [CrossRef]
• Duh RW, Asal NR. Mortality among laundry and dry-cleaning workers in Oklahoma. Am J Public Health. 1984;74:1278–1280. [PMC free article: PMC1652027] [PubMed: 6496825] [CrossRef]
• Earnest GS. A control technology evaluation of state-of-the-art, perchloroethylene dry-cleaning machines. Appl Occup Environ Hyg. 2002;17:352–359. [PubMed: 12018399] [CrossRef]
• Ebrahim AS, Babakrishnan K, Sakthisekaran D. Perchloroethylene-induced alterations in glucose metabolism and their prevention by 2-deoxy-D-glucose and vitamin E in mice. J Appl Toxicol. 1996;16:339–348. [PubMed: 8854221] [CrossRef]
• Ebrahim AS, Babu E, Thirunavukkarasu C, Sakthisekaran D. Protective role of vitamin E, 2-deoxy-D-glucose, and taurine on perchloroethylene induced alterations in ATPases. Drug Chem Toxicol. 2001;24:429–437. [PubMed: 11665651] [CrossRef]
• ECHA; European Chemicals Agency (2013). Tetrachloroethylene. Available at http://www.echa.europa.eu/. Accessed 10 December 2013.
• Echeverria D, Heyer N Checkoway H et al. (1994). A behavioral investigation of occupational exposures to solvents: Perchloroethylene among dry cleaners, and styrene among reinforced fiberglass laminators. Seattle, WA: Battelle Centers for Public Health Research and Evaluation.
• Echeverria D, White RF, Sampaio C. A behavioral evaluation of PCE exposure in patients and dry cleaners: a possible relationship between clinical and preclinical effects. J Occup Environ Med. 1995;37:667–680. [PubMed: 7670913] [CrossRef]
• ECSA; European Chlorinated Solvent Association (2012). All about “Per” in a nutshell. Available online at: http://www.eurochlor.org/media/61344/05-infosheet-public-per-dry-cleaning.pdf. Accessed 22 October 2013.
• Eddleston MT, Polakoff PL (1974). Health Hazard Evaluation/Toxicity Determination. Swiss Cleansing Company, Providence, Rhode Island. HHE Report No. 73-86-114; NTIS PB, 232-742. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health. Available online at: http://www.ntis.gov/search/product.aspx?ABBR=PB232742. Accessed 22 October 2013.
• Edmondson GK, Palin MJ (1993). Occupational Exposure to Perchloroethylene in the UK Drycleaning Industry. Harrogate, North Yorkshire, United Kingdom: Fabric Care Research Association.
• Elfarra AA, Krause RJ. S-(1,2,2-trichlorovinyl)-L-cysteine sulfoxide, a reactive metabolite of S-(1,2,2-Trichlorovinyl)-L-cysteine formed in rat liver and kidney microsomes, is a potent nephrotoxicant. J Pharmacol Exp Ther. 2007;321:1095–1101. [PubMed: 17347324] [CrossRef]
• Elfarra AA, Lash LH, Anders MW. Alpha-ketoacids stimulate rat renal cysteine conjugate beta-lyase activity and potentiate the cytotoxicity of S-(1,2-dichlorovinyl)-L-cysteine. Mol Pharmacol. 1987;31:208–212. [PubMed: 3807895]
• Emara AM, Abo El-Noor MM, Hassan NA, Wagih AA. Immunotoxicity and hematotoxicity induced by tetrachloroethylene in egyptian dry cleaning workers. Inhal Toxicol. 2010;22:117–124. [PubMed: 20044880] [CrossRef]
• EPA (1982). An Exposure and Risk Assessment for Tetrachloroethylene. Gilbert D, Goyer M, Lyman W, et al., editors. Washington DC: United States Environmental Protection Agency, Office of Water Regulations and Standards, No. EPA-440/4-85-015, 1–147.
• EPA (1985). Health Assessment Document for Tetrachloroethylene (Perchloroethylene) - Final Report. Washington, DC: Research Triangle Park, NC, No. (EPA-600/8-82-005F; US NTIS PB85-249704), United States Environmental Protection Agency .
• EPA (1988). Methods for the Determination of Organic Compounds in Drinking Water. Cincinnati, OH, USA: Environmental Monitoring Systems Laboratory, No. EPA-600/4-88-039; US NTIS PB89-220461, 5–87, 255–323 United States Environmental Protection Agency .
• EPA (1995a). Volatile Organic Compounds in Water by Purge and Trap Capillary Column Gas Chromatography with Photoionization and Electrolytic Conductivity Detectors in Series. Cincinnati, OH, USA: Environmental Monitoring Systems Laboratory, No. (Method 502.2, Rev 2.1). United States Environmental Protection Agency .
• EPA (1995b). Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography/Mass Spectrometry. Cincinnati, OH, USA: Environmental Monitoring Systems Laboratory, No. (Method 524.2, Rev 4.1). United States Environmental Protection Agency .
• EPA (1995c). Determination of Chlorination Disinfection Byproducts, Chlorinated Solvents, and Halogenated Pesticides/Herbicides in Drinking Water by Liquid-liquid Extraction and Gas Chromatography with Electron Capture Detection. Cincinnati, OH, USA: Environmental Monitoring Systems Laboratory, No. (Method 551.1, Rev 1.0), United States Environmental Protection Agency 1–61.
• EPA (1996a). Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. Cincinnati, OH, USA: Environmental Monitoring Systems Laboratory, No. SW-846, Method 8021B United States Environmental Protection Agency .
• EPA (1996b). Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. Cincinnati, OH, USA: Environmental Monitoring Systems Laboratory, No. SW-846, Method 8260B United States Environmental Protection Agency .
• EPA (1999a). Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air. Determination of Volatile Organic Compounds in Ambient Air Using Active Sampling Onto Sorbent Tubes. United States Environmental Protection Agency., Cincinnati, OH, USA: No. 2nd Ed. Method TO-17.
• EPA (1999b). Compendium of Methods for the Determination of Toxic Organic Compounds in Ambient Air, Determination of Volatile Organic Compounds (VOCs) In Air Collected In Specially-Prepared Canisters And Analyzed By Gas Chromatography/Mass Spectrometry (GC/MS). United States Environmental Protection Agency Cincinnati, OH, USA: No. 2nd Ed. Method TO-15.
• EPA (2012). Toxicological review of Tetrachloroethylene (Perchloroethylene) (CAS No. 127–18–4) in support of summary information on the Integrated Risk Information System (IRIS). EPA/635/R-08/011F. Washington, DC, USA .
• EPA (2013). Consumer Fact Sheet on Tetrachloroethylene. Available online at: http://www.epa.gov/safewater/pdfs/factsheets/voc/tetrachl.pdf. Accessed 23 July 2013.
• Erdman AR, Mangravite LM, Urban TJ, et al. The human organic anion transporter 3 (OAT3; SLC22A8): genetic variation and functional genomics. Am J Physiol Renal Physiol. 2006;290:F905–F912. [PubMed: 16291576] [CrossRef]
• Eskenazi B, Wyrobek AJ, Fenster L, et al. A study of the effect of perchloroethylene exposure on semen quality in dry-cleaning workers. Am J Ind Med. 1991;20:575–591. [PubMed: 1793101] [CrossRef]
• Essing HG, Schäcke G, Schaller KH, Valentin H. [Occupational–medicine studies on the dynamics of perchlorethylene in the organism] Med Welt. 1973;24:242–244. [PubMed: 4731690]
• European Centre for Ecotoxicology and Toxicology of Chemicals (1990). Trichloroethylene: Assessment of Human Carcinogenic Hazard. (ECETOC Technical Report No. 37). Brussels, Belgium.
• European Commission (2009). Recommendation of the Scientific Committee on Occupational Exposure Limits for Tetrachloroethylene (Perchloroethylene). Available online at: http://ec.europa.eu/social/keyDocuments.jsp?pager.offset=40&langId=en&mode=advancedSubmit&year=0&country=0&type=0&advSearchKey=SCOEL%20recommendation. Accessed 25 July 2013.
• Fabricant JD, Chalmers JH Jr (1980). Evidence of the mutagenicity of ethylene dichloride and structurally related compounds. In: Ethylene Dichloride: A Potential Health Risk (Banbury Report 5). Ames B, Infante P, Reitz R, editors. Cold Spring Harbor, NY: CSH Press, pp. 309–329.
• Fan C, Wang GS, Chen YC, Ko CH. Risk assessment of exposure to volatile organic compounds in groundwater in Taiwan. Sci Total Environ. 2009;407:2165–2174. [PubMed: 19167026] [CrossRef]
• Fender H, editor (1993). [Chromosome analyses among dry-cleaners.] [in German] Munich, Germany: MMV Verlag.
• Fernandez J, Guberan E, Caperos J. Experimental human exposures to tetrachloroethylene vapor and elimination in breath after inhalation. Am Ind Hyg Assoc J. 1976;37:143–150. [PubMed: 1266733] [CrossRef]
• Ferroni C, Selis L, Mutti A, et al. Neurobehavioral and neuroendocrine effects of occupational exposure to perchloroethylene. Neurotoxicology. 1992;13:243–247. [PubMed: 1508425]
• Filser JG, Bolt HM. Pharmacokinetics of halogenated ethylenes in rats. Arch Toxicol. 1979;42:123–136. [PubMed: 485853] [CrossRef]
• Fisher J, Mahle D, Bankston L, et al. Lactational transfer of volatile chemicals in breast milk. Am Ind Hyg Assoc J. 1997;58:425–431. [PubMed: 9183837] [CrossRef]
• Fleming-Jones ME, Smith RE. Volatile organic compounds in foods: a five year study. J Agric Food Chem. 2003;51:8120–8127. [PubMed: 14690406] [CrossRef]
• Forand SP, Lewis-Michl EL, Gomez MI. Adverse birth outcomes and maternal exposure to trichloroethylene and tetrachloroethylene through soil vapor intrusion in New York State. Environ Health Perspect. 2012;120:616–621. [PMC free article: PMC3339451] [PubMed: 22142966] [CrossRef]
• Franchini I, Cavatorta A, Falzoi M, et al. Early indicators of renal damage in workers exposed to organic solvents. Int Arch Occup Environ Health. 1983;52:1–9. [PubMed: 6603422] [CrossRef]
• Frantz SW, Watanabe PG. Tetrachloroethylene: balance and tissue distribution in male Sprague-Dawley rats by drinking-water administration. Toxicol Appl Pharmacol. 1983;69:66–72. [PubMed: 6857689] [CrossRef]
• Frasch HF, Barbero AM. A paired comparison between human skin and hairless guinea pig skin in vitro permeability and lag time measurements for 6 industrial chemicals. Cutan Ocul Toxicol. 2009;28:107–113. [PubMed: 19552540] [CrossRef]
• Gaertner RR, Trpeski L, Johnson KC., Canadian Cancer Registries Epidemiology Research Group. A case-control study of occupational risk factors for bladder cancer in Canada. Cancer Causes Control. 2004;15:1007–1019. [PubMed: 15801485] [CrossRef]
• Gallagher LG, Vieira VM, Ozonoff D, et al. Risk of breast cancer following exposure to tetrachloroethylene-contaminated drinking water in Cape Cod, Massachusetts: reanalysis of a case-control study using a modified exposure assessment. Environ Health. 2011;10:47. [PMC free article: PMC3125233] [PubMed: 21600013] [CrossRef]
• Galloway SM, Armstrong MJ, Reuben C, et al. Chromosome aberrations and sister chromatid exchanges in Chinese hamster ovary cells: evaluations of 108 chemicals. Environ Mol Mutagen. 1987;10 Suppl 10:1–175. [PubMed: 3319609] [CrossRef]
• Garetano G, Gochfeld M. Factors influencing tetrachloroethylene concentrations in residences above dry-cleaning establishments. Arch Environ Health. 2000;55:59–68. [PubMed: 10735522] [CrossRef]
• Gargas ML, Burgess RJ, Voisard DE, et al. Partition coefficients of low-molecular-weight volatile chemicals in various liquids and tissues. Toxicol Appl Pharmacol. 1989;98:87–99. [PubMed: 2929023] [CrossRef]
• Garnier R, Bédouin J, Pépin G, Gaillard Y. Coin-operated dry cleaning machines may be responsible for acute tetrachloroethylene poisoning: report of 26 cases including one death. J Toxicol Clin Toxicol. 1996;34:191–197. [PubMed: 8618253] [CrossRef]
• Gearhart JM, Mahle DA, Greene RJ, et al. Variability of physiologically based pharmacokinetic (PBPK) model parameters and their effects on PBPK model predictions in a risk assessment for perchloroethylene (PCE). Toxicol Lett. 1993;68:131–144. [PubMed: 8516760] [CrossRef]
• Gennari P, Naldi M, Motta R, et al. gamma-Glutamyltransferase isoenzyme pattern in workers exposed to tetrachloroethylene. Am J Ind Med. 1992;21:661–671. [PubMed: 1351699] [CrossRef]
• Gentry PR, Covington TR, Clewell HJ 3rd. Evaluation of the potential impact of pharmacokinetic differences on tissue dosimetry in offspring during pregnancy and lactation. Regul Toxicol Pharmacol. 2003;38:1–16. [PubMed: 12878049] [CrossRef]
• Germolec DR, Yang RSH, Ackermann MF, et al. Toxicology studies of a chemical mixture of 25 groundwater contaminants. II. Immunosuppression in B6C3F1 mice. Fundam Appl Toxicol. 1989;13:377–387. [PubMed: 2515087] [CrossRef]
• GESTIS (2012). GESTIS International Limit Values – Databases hazardous substances. Institute for Work Protection of the German Accident Insurance. Available at http://limitvalue.ifa.dguv.de/Webform_gw.aspx. Accessed 19 November 2013.
• Ghantous H, Danielsson BRG, Dencker L, et al. Trichloroacetic acid accumulates in murine amniotic fluid after tri- and tetrachloroethylene inhalation. Acta Pharmacol Toxicol (Copenh). 1986;58:105–114. [PubMed: 3754680] [CrossRef]
• Glauser J, Ishikawa Y (2008). Chemical Industries Newsletter. Chemical Economics Handbook Marketing, Research Report: C2 Chlorinated Solvents. SRI Consulting. Available online at: http://chemical.ihs.com/nl/Public/2008Aug.pdf. Accessed 24 July 2013.
• Gluszczowa M. 1988[Evaluation of the health status of dry cleaning plant workers exposed to tetrachloroethylene][in Czech]Med Pr 39200–205. [PubMed: 3226288]
• Gobba F, Righi E, Fantuzzi G, et al. Two-year evolution of perchloroethylene-induced color-vision loss. Arch Environ Health. 1998;53:196–198. [PubMed: 9814715] [CrossRef]
• Gobba F, Righi E, Fantuzzi G, et al. Perchloroethylene in alveolar air, blood, and urine as biologic indices of low-level exposure. J Occup Environ Med. 2003;45:1152–1157. [PubMed: 14610396] [CrossRef]
• Gobba F, Rosa P, Ghittori S, et al. [Environmental and biological monitoring of occupational exposure to perchloroethylene in dry-cleaning shops] Med Lav. 1997;88:24–36. [PubMed: 9229671]
• Gokhale S, Kohajda T, Schlink U. Source apportionment of human personal exposure to volatile organic compounds in homes, offices and outdoors by chemical mass balance and genetic algorithm receptor models. Sci Total Environ. 2008;407:122–138. [PubMed: 18822447] [CrossRef]
• Gold LS, De Roos AJ, Waters M, Stewart P. Systematic literature review of uses and levels of occupational exposure to tetrachloroethylene. J Occup Environ Hyg. 2008;5:807–839. [Review] [PubMed: 18949603] [CrossRef]
• Gold LS, Stewart PA, Milliken K, et al. The relationship between multiple myeloma and occupational exposure to six chlorinated solvents. Occup Environ Med. 2011;68:391–399. [PMC free article: PMC3094509] [PubMed: 20833760] [CrossRef]
• Goldsworthy TL, Lyght O, Burnett VL, Popp JA. Potential role of alpha-2u-globulin, protein droplet accumulation, and cell replication in the renal carcinogenicity of rats exposed to trichloroethylene, perchloroethylene, and pentachloroethane. Toxicol Appl Pharmacol. 1988;96:367–379. [PubMed: 2461605] [CrossRef]
• Goldsworthy TL, Popp JA. Chlorinated hydrocarbon-induced peroxisomal enzyme activity in relation to species and organ carcinogenicity. Toxicol Appl Pharmacol. 1987;88:225–233. [PubMed: 3564041] [CrossRef]
• Gotoh Y, Kato Y, Stieger B, et al. Gender difference in the Oatp1-mediated tubular reabsorption of estradiol 17b-D-glucuronide in rats. Am J Physiol. 2001;282:E1254. [PubMed: 12006354]
• Green T. Chloroethylenes: a mechanistic approach to human risk evaluation. Annu Rev Pharmacol Toxicol. 1990;30:73–89. [PubMed: 2188582] [CrossRef]
• Green T, Odum J, Nash JA, Foster JR. Perchloroethylene-induced rat kidney tumors: an investigation of the mechanisms involved and their relevance to humans. Toxicol Appl Pharmacol. 1990;103:77–89. [PubMed: 1969182] [CrossRef]
• Greenberg AE, Clesceri LS, Eaton AD (1992). Standard Methods for the Examination of Water and Wastewater. 18th Ed. Washington, DC: American Public Health Association/American Water Works Association/Water Environment Federation.
• Greim H, Bonse G, Radwan Z, et al. Mutagenicity in vitro and potential carcinogenicity of chlorinated ethylenes as a function of metabolic oxiran formation. Biochem Pharmacol. 1975;24:2013–2017. [PubMed: 1108881] [CrossRef]
• Gromiec JP, Wesołowski W, Brzeźnicki S, et al. Occupational exposure to rubber vulcanization products during repair of rubber conveyor belts in a brown coal mine. J Environ Monit. 2002;4:1054–1059. [PubMed: 12509065] [CrossRef]
• Guberan E, Fernandez J. Control of industrial exposure to tetrachloroethylene by measuring alveolar concentrations: theoretical approach using a mathematical model. Br J Ind Med. 1974;31:159–167. [PMC free article: PMC1009571] [PubMed: 4830767]
• Gulyas H, Hemmerling L. Tetrachloroethene air pollution originating from coin-operated dry-cleaning establishments. Environ Res. 1990;53:90–99. [PubMed: 2226380] [CrossRef]
• Gunter BJ, Lybarger JA (1979). NIOSH Health Hazard Evaluation Report, Jonas Brothers Taxidermy Co., Denver, CO. HETA 78-95-596. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Hajimiragha H, Ewers U, Jansen-Rosseck R, Brockhaus A. Human exposure to volatile halogenated hydrocarbons from the general environment. Int Arch Occup Environ Health. 1986;58:141–150. [PubMed: 3744568] [CrossRef]
• Hake CL, Stewart RD. Human exposure to tetrachloroethylene: inhalation and skin contact. Environ Health Perspect. 1977;21:231–238. [PMC free article: PMC1475318] [PubMed: 612448] [CrossRef]
• Hanioka N, Jinno H, Takahashi A, et al. Interaction of tetrachloroethylene with rat hepatic microsomal P450-dependent monooxygenases. Xenobiotica. 1995;25:151–165. b. [PubMed: 7618343] [CrossRef]
• Hanioka N, Jinno H, Toyo’oka T, et al. Induction of rat liver drug-metabolizing enzymes by tetrachloroethylene. Arch Environ Contam Toxicol. 1995;28:273–280. a. [PubMed: 7726643] [CrossRef]
• Hanley KW (1993). NIOSH Health Hazard Evaluation Report, Daubert Coated Products Inc., Dixon, IL. HETA 91-0004-2316. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health .
• Hansch C, Leo A, Hoekman D (1995). Exploring QSAR: Hydrophobic, electronic, and steric constants. Washington, DC: American Chemical Society, p. 4.
• Hartge P, Cahill JI, West D, et al. Design and methods in a multi-center case-control interview study. Am J Public Health. 1984;74:52–56. [PMC free article: PMC1651387] [PubMed: 6689843] [CrossRef]
• Hartle R, Aw TC (1983). NIOSH Health Hazard Evaluation Report, Hoover Co., North Canton, OH. HETA 82-127-1370. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health .
• Hartle R, Aw TC (1984). NIOSH Health Hazard Evaluation Report, Hoover Co., North Canton, OH. HETA 82-280-1 407. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Hartmann A, Speit G. Genotoxic effects of chemicals in the single cell gel (SCG) test with human blood cells in relation to the induction of sister-chromatid exchanges (SCE). Mutat Res. 1995;346:49–56. [PubMed: 7530329] [CrossRef]
• Haworth S, Lawlor T, Mortelmans K, et al. Salmonella mutagenicity test results for 250 chemicals. Environ Mutagen. 1983;5 Suppl 1:1–142. [PubMed: 6365529] [CrossRef]
• Hayes JR, Condie LW Jr, Borzelleca JF. The subchronic toxicity of tetrachloroethylene (perchloroethylene) administered in the drinking water of rats. Fundam Appl Toxicol. 1986;7:119–125. [PubMed: 3732662] [CrossRef]
• Haynes WM (2012). CRC Handbook of Chemistry and Physics, (Internet Version 2012). Boca Raton, FL: CRC Press/Taylor and Francis, No. EPA/625/R-96/010b, 92nd Ed. http://www.epa.gov/osw/hazard/testmethods/sw846/pdfs/8260b.pdf.
• Heineman EF, Cocco P, Gómez MR, et al. Occupational exposure to chlorinated aliphatic hydrocarbons and risk of astrocytic brain cancer. Am J Ind Med. 1994;26:155–169. [PubMed: 7977393] [CrossRef]
• Henschler D. Metabolism and mutagenicity of halogenated olefins–a comparison of structure and activity. Environ Health Perspect. 1977;21:61–64. [PMC free article: PMC1475339] [PubMed: 348459]
• Henschler D (1987). Mechanisms of genotoxicity of chlorinated aliphatic hydrocarbons. In: Selectivity and Molecular Mechanisms of Toxicity. De Matteis F, Lock EA, editors. New York: MacMillan, pp. 153–181.
• Henschler D, Bonse G. Metabolic activation of chlorinated ethylenes: dependence of mutagenic effect on electrophilic reactivity of the metabolically formed epoxides. Arch Toxicol. 1977;39:7–12. [PubMed: 579983] [CrossRef]
• Hervin R, Shama S, Ruhe RL (1972). NIOSH Health Hazard Evaluation Report, Aerosol Techniques, Inc., Danville, IL. HETA 71-25-20. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Hervin RL, Lucas J (1973). NIOSH Health Hazard Evaluation Report, The Budd Company-Automotive Division, Clinton, MI. HETA 72-35-34. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health .
• Hiatt MH, Pia JH. Screening processed milk for volatile organic compounds using vacuum distillation/gas chromatography/mass spectrometry. Arch Environ Contam Toxicol. 2004;46:189–196. [PubMed: 15106669]
• Hickman JC (1993). Chlorocarbons and chlorohydrocarbons. Kroschwitz JI, Howe-Grant M, editors. New York, USA: John Wiley &Sons, pp. 429–430.
• Honma T, Hasegawa H, Sato M, Sudo A. Changes of free amino acid content in rat brain after exposure to trichloroethylene and tetrachloroethylene. Ind Health. 1980;18:1–7. a. [PubMed: 7451242] [CrossRef]
• Honma T, Sudo A, Miyagawa M, et al. Effects of exposure to trichloroethylene and tetrachloroethylene on the contents of acetylcholine, dopamine, norepinephrine and serotonin in rat brain. Ind Health. 1980;18:171–178. b. [PubMed: 7251397] [CrossRef]
• HSDB (2012). Hazardous Substances Data Bank: Tetrachloroethylene. Bethesda, MD, National Library of Medicine. Available online at: http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?HSDB. Accessed 24 July 2013.
• Huybrechts T, Dewulf J, Van Langenhove H. Priority volatile organic compounds in surface waters of the southern North Sea. Environ Pollut. 2005;133:255–264. [PubMed: 15519456] [CrossRef]
• IARC. Some halogenated hydrocarbons. IARC Monogr Eval Carcinog Risk Chem Hum. 1979;20:1–609. [PubMed: 296120]
• IARC. Overall evaluations of carcinogenicity: an updating of IARC Monographs volumes 1 to 42. IARC Monogr Eval Carcinog Risks Hum Suppl. 1987;7:1–440. [PubMed: 3482203]
• IARC. 1995Dry cleaning, some chlorinated solvents and other industrial chemicals. IARC Monogr Eval Carcinog Risks Hum 631–551.PMID:9139130. [PMC free article: PMC7681564] [PubMed: 9139128]
• IARC. Species Differences in Thyroid, Kidney and Urinary Bladder Carcinogenesis. Proceedings of a consensus conference. Lyon, France, 3–7 November 1997. IARC Sci Publ. 1999;147:1–225. [PubMed: 10627184]
• Ikeda M. Metabolism of trichloroethylene and tetrachloroethylene in human subjects. Environ Health Perspect. 1977;21:239–245. [PMC free article: PMC1475342] [PubMed: 612449] [CrossRef]
• Ikeda M, Imanura T. Biological half-life of trichloroethylene and tetrachloroethylene in human subjects. Int Arch Arbeitsmed. 1973;31:209–224. [PubMed: 4593976] [CrossRef]
• Ikeda M, Koizumi A, Watanabe T, et al. Cytogenetic and cytokinetic investigations on lymphocytes from workers occupationally exposed to tetrachloroethylene. Toxicol Lett. 1980;5:251–256. [PubMed: 7466854] [CrossRef]
• Ikeda M, Otsuji H, Imamura T, Komoike Y. Urinary excretion of total trichloro-compounds, trichloroethanol, and trichloroacetic acid as a measure of exposure to trichloroethylene and tetrachloroethylene. Br J Ind Med. 1972;29:328–333. [PMC free article: PMC1009432] [PubMed: 5044605]
• Illing HPA, Mariscotti SP, Smith AM (1987) Tetrachloroethylene (Tetrachloroethene, Perchloroethylene). London, England: Her Majesty's Stationery Office International, Health and Safety Executive Toxicity Review.
• International Fabricare Institute. Perchloroethylene vapor in dry cleaning plants. Focus Dry-cleaning. 1987;11:1–17.
• Isacson P, Bean JA, Splinter R, et al. Drinking water and cancer incidence in Iowa. III. Association of cancer with indices of contamination. Am J Epidemiol. 1985;121:856–869. [PubMed: 4014178]
• Jackson MA, Stack HF, Waters MD. The genetic toxicology of putative nongenotoxic carcinogens. Mutat Res. 1993;296:241–277. [PubMed: 7680106] [CrossRef]
• Jakobson I, Wahlberg JE, Holmberg B, Johansson G. Uptake via the blood and elimination of 10 organic solvents following epicutaneous exposure of anesthetized guinea pigs. Toxicol Appl Pharmacol. 1982;63:181–187. [PubMed: 7089968] [CrossRef]
• Jang JY, Kang SK, Chung HK. Biological exposure indices of organic solvents for Korean workers. Int Arch Occup Environ Health. 1993;65 Suppl:S219–S222. [PubMed: 8406930] [CrossRef]
• Jankovic J (1980). NIOSH Health Hazard Evaluation Report, Patriot Coal Company Laboratory, Kingwood,WV. HETA M-TA-80-109-110. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Janulewicz PA, White RF, Winter MR, et al. Risk of learning and behavioral disorders following prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water. Neurotoxicol Teratol. 2008;30:175–185. [PMC free article: PMC2494864] [PubMed: 18353612] [CrossRef]
• JISA; Japan Industrial Safety Association (1993). Carcinogenicity Study of Tetrachloroethylene by Inhalation in Rats and Mice. Hadano, Japan: Japan Industrial Safety Association.
• Jo WK, Kim SH. Worker exposure to aromatic volatile organic compounds in dry-cleaning stores. AIHAJ. 2001;62:466–471. [PubMed: 11549140] [CrossRef]
• Johansen K, Tinnerberg H, Lynge E. Use of history science methods in exposure assessment for occupational health studies. Occup Environ Med. 2005;62:434–441. [PMC free article: PMC1741048] [PubMed: 15961618] [CrossRef]
• Johnsrud EK, Koukouritaki SB, Divakaran K, et al. Human hepatic CYP2E1 expression during development. J Pharmacol Exp Ther. 2003;307:402–407. [PubMed: 14500779] [CrossRef]
• Jonker D, Woutersen RA, Feron VJ. Toxicity of mixtures of nephrotoxicants with similar or dissimilar mode of action. Food Chem Toxicol. 1996;34:1075–1082. [PubMed: 9119318] [CrossRef]
• Karami S, Colt JS, Schwartz K, et al. A case-control study of occupation/industry and renal cell carcinoma risk. BMC Cancer. 2012;12:344. [PMC free article: PMC3502582] [PubMed: 22873580] [CrossRef]
• Karlsson JE, Rosengren LE, Kjellstrand P, Haglid KG. Effects of low-dose inhalation of three chlorinated aliphatic organic solvents on deoxyribonucleic acid in gerbil brain. Scand J Work Environ Health. 1987;13:453–458. [PubMed: 3433047] [CrossRef]
• Kato I, Koenig KL, Watanabe-Meserve H, et al. Personal and occupational exposure to organic solvents and risk of non-Hodgkin’s lymphoma (NHL) in women (United States). Cancer Causes Control. 2005;16:1215–1224. [PubMed: 16215872] [CrossRef]
• Katz RM, Jowett D. Female laundry and dry-cleaning workers in Wisconsin: a mortality analysis. Am J Public Health. 1981;71:305–307. [PMC free article: PMC1619803] [PubMed: 7468868] [CrossRef]
• Kauppinen T, Toikkanen J, Pedersen D, et al. Occupational exposure to carcinogens in the European Union. Occup Environ Med. 2000;57:10–18. [PMC free article: PMC1739859] [PubMed: 10711264] [CrossRef]
• Kerr RE (1972). Environmental Exposures to Tetrachloroethylene in the Dry-cleaning Industry. M.S.Thesis, Cincinnati, OH, USA: University of Cincinnati.
• Kjellstrand P, Holmquist B, Kanje M, et al. Perchloroethylene: effects on body and organ weights and plasma butyrylcholinesterase activity in mice. Acta Pharmacol Toxicol (Copenh). 1984;54:414–424. [PubMed: 6464786] [CrossRef]
• Klein P, Kurz J (1994). Study on preventive measures to reduce the concentration of solvents in the vicinity of textile cleaning shops. Bönnigheim, Hohenstein e.V. Physiological Institute on Clothing.
• Kline SA, McCoy EC, Rosenkranz HS, Van Duuren BL. Mutagenicity of chloroalkene epoxides in bacterial systems. Mutat Res. 1982;101:115–125. [PubMed: 7048080] [CrossRef]
• Kobayashi Y, Hirokawa N, Ohshiro N, et al. Differential gene expression of organic anion transporters in male and female rats. Biochem Biophys Res Commun. 2002;290:482–487. [PubMed: 11779196] [CrossRef]
• Koch R, Schlegelmilch R, Wolf HU. Genetic effects of chlorinated ethylenes in the yeast Saccharomyces cerevisiae. Mutat Res. 1988;206:209–216. [PubMed: 3050501] [CrossRef]
• Koizumi A. Potential of physiologically based pharmacokinetics to amalgamate kinetic data of trichloroethylene and tetrachloroethylene obtained in rats and man. Br J Ind Med. 1989;46:239–249. [PMC free article: PMC1009763] [PubMed: 2713280]
• Köppel C, Arndt I, Arendt U, Koeppe P. Acute tetrachloroethylene poisoning–blood elimination kinetics during hyperventilation therapy. J Toxicol Clin Toxicol. 1985;23:103–115. [PubMed: 4057308] [CrossRef]
• Kostopoulou MN, Golfinopoulos SK, Nikolaou AD, et al. Volatile organic compounds in the surface waters of northern Greece. Chemosphere. 2000;40:527–532. [PubMed: 10665390] [CrossRef]
• Krasowski MD, Harrison NL. The actions of ether, alcohol and alkane general anaesthetics on GABA_A and glycine receptors and the effects of TM2 and TM3 mutations. Br J Pharmacol. 2000;129:731–743. [PMC free article: PMC1571881] [PubMed: 10683198] [CrossRef]
• Kringstad KP, Ljungquist PO, De Sousa F, Stroemberg LM. Identification and mutagenic properties of some chlorinated aliphatic compounds in the spent liquor from kraft pulp chlorination. Environ Sci Technol. 1981;15:562–566. [PubMed: 22283948] [CrossRef]
• Kyrklund T, Alling C, Kjellstrand P, Haglid KG. Chronic effects of perchloroethylene on the composition of lipid and acyl groups in cerebral cortex and hippocampus of the gerbil. Toxicol Lett. 1984;22:343–349. [PubMed: 6485008] [CrossRef]
• Kyrklund T, Kjellstrand P, Haglid KG. Lipid composition and fatty acid pattern of the gerbil brain after exposure to perchloroethylene. Arch Toxicol. 1987;60:397–400. [PubMed: 3662814] [CrossRef]
• Kyrklund T, Kjellstrand P, Haglid KG. Effects of exposure to Freon 11, 1,1,1-trichloroethane or perchloroethylene on the lipid and fatty-acid composition of rat cerebral cortex. Scand J Work Environ Health. 1988;14:91–94. [PubMed: 3387963] [CrossRef]
• Kyrklund T, Kjellstrand P, Haglid KG. Long-term exposure of rats to perchloroethylene, with and without a post-exposure solvent-free recovery period: effects on brain lipids. Toxicol Lett. 1990;52:279–285. [PubMed: 2389258] [CrossRef]
• Lacey JV Jr, Garabrant DH, Laing TJ, et al. Petroleum distillate solvents as risk factors for undifferentiated connective tissue disease (UCTD). Am J Epidemiol. 1999;149:761–770. [PubMed: 10206626] [CrossRef]
• Lash LH. Glutathione-dependent bioactivation. Curr Protoc Toxicol. 2007;34:7.9.1–7.9.16. [PubMed: 23045148]
• Lash LH, Fisher JW, Lipscomb JC, Parker JC. Metabolism of trichloroethylene. Environ Health Perspect. 2000;108 Suppl 2:177–200. [PMC free article: PMC1637769] [PubMed: 10807551] [CrossRef]
• Lash LH, Parker JC. Hepatic and renal toxicities associated with perchloroethylene. Pharmacol Rev. 2001;53:177–208. [PubMed: 11356983]
• Lash LH, Putt DA, Cai H. Membrane transport function in primary cultures of human proximal tubular cells. Toxicology. 2006;228:200–218. [PubMed: 16997449] [CrossRef]
• Lash LH, Putt DA, Huang P, et al. Modulation of hepatic and renal metabolism and toxicity of trichloroethylene and perchloroethylene by alterations in status of cytochrome P450 and glutathione. Toxicology. 2007;235:11–26. [PMC free article: PMC1976278] [PubMed: 17433522] [CrossRef]
• Lash LH, Qian W, Putt DA, et al. Glutathione conjugation of perchloroethylene in rats and mice in vitro: sex-, species-, and tissue-dependent differences. Toxicol Appl Pharmacol. 1998;150:49–57. [PubMed: 9630452] [CrossRef]
• Lash LH, Qian W, Putt DA, et al. Renal and hepatic toxicity of trichloroethylene and its glutathione-derived metabolites in rats and mice: sex-, species-, and tissue-dependent differences. J Pharmacol Exp Ther. 2001;297:155–164. [PubMed: 11259540]
• Lash LH, Qian W, Putt DA, et al. Renal toxicity of perchloroethylene and S-(1,2,2-trichlorovinyl)glutathione in rats and mice: sex- and species-dependent differences. Toxicol Appl Pharmacol. 2002;179:163–171. [PubMed: 11906246] [CrossRef]
• Laslo-Baker D, Barrera M, Knittel-Keren D, et al. Child neurodevelopmental outcome and maternal occupational exposure to solvents. Arch Pediatr Adolesc Med. 2004;158:956–961. [PubMed: 15466682] [CrossRef]
• Laughter AR, Dunn CS, Swanson CL, et al. Role of the peroxisome proliferator-activated receptor alpha (PPARalpha) in responses to trichloroethylene and metabolites, trichloroacetate and dichloroacetate in mouse liver. Toxicology. 2004;203:83–98. [PubMed: 15363585] [CrossRef]
• Lauwerys R, Herbrand J, Buchet JP, et al. Health surveillance of workers exposed to tetrachloroethylene in dry-cleaning shops. Int Arch Occup Environ Health. 1983;52:69–77. [PubMed: 6874093] [CrossRef]
• Lee LJ, Chan CC, Chung CW, et al. Health risk assessment on residents exposed to chlorinated hydrocarbons contaminated in groundwater of a hazardous waste site. J Toxicol Environ Health A. 2002;65:219–235. [PubMed: 11911487] [CrossRef]
• Lehmann I, Rehwagen M, Diez U, et al. Leipzig Allergy Risk Children Study. Enhanced in vivo IgE production and T cell polarization toward the type 2 phenotype in association with indoor exposure to VOC: results of the LARS study. Int J Hyg Environ Health. 2001;204:211–221. [PubMed: 11833293] [CrossRef]
• Lehmann I, Thoelke A, Rehwagen M, et al. The influence of maternal exposure to volatile organic compounds on the cytokine secretion profile of neonatal T cells. Environ Toxicol. 2002;17:203–210. [PubMed: 12112628] [CrossRef]
• Levine B, Fierro MF, Goza SW, Valentour JC. A tetrachloroethylene fatality. J Forensic Sci. 1981;26:206–209. [PubMed: 7205186]
• Lillford L, Beevers C, Bowen D, Kirkland D. 2010RE: DNA damage detected by the alkaline comet assay in the liver of mice after oral administration of tetrachloroethylene. (Mutagenesis, 25, 133–138, 2010). Mutagenesis 25427–428.author reply 429–430. 10.1093/mutage/geq020 . [PubMed: 20453059] [CrossRef]
• Linak E, Leder A, Yoshida Y (1992). Chlorinated Solvents. In: Chemical Economies Handbook. Menlo Park, CA, USA: SRI International, 632.3000–632.3001.
• Ljubojevic M, Herak-Kramberger CM, Hagos Y, et al. Rat renal cortical OAT1 and OAT3 exhibit gender differences determined by both androgen stimulation and estrogen inhibition. Am J Physiol Renal Physiol. 2004;287:F124–F138. [PubMed: 15010355] [CrossRef]
• Lopreato GF, Phelan R, Borghese CM, et al. Inhaled drugs of abuse enhance serotonin-3 receptor function. Drug Alcohol Depend. 2003;70:11–15. [PubMed: 12681521] [CrossRef]
• Love JR (1982). NIOSH Health Hazard Evaluation Report, King-Smith Printing Co., Detroit, MI. HETA 81-310-1039. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health .
• Ludwig HR (1981). Occupational exposure to perchloroethylene in the dry-cleaning industry. Cincinnati, OH, USA: United States National Institute for Occupational Safetyand Health, pp. 1–102 .
• Ludwig HR, Meister MV, Roberts DR, Cox C. Worker exposure to perchloroethylene in the commercial dry-cleaning industry. Am Ind Hyg Assoc J. 1983;44:600–605. [PubMed: 6624647] [CrossRef]
• Lukaszewski T. Acute tetrachloroethylene fatality. Clin Toxicol. 1979;15:411–415. [PubMed: 540489] [CrossRef]
• Lynge E, Andersen A, Rylander L, et al. Cancer in persons working in dry-cleaning in the Nordic countries. Environ Health Perspect. 2006;114:213–219. [PMC free article: PMC1367834] [PubMed: 16451857] [CrossRef]
• Lynge E, Carstensen B, Andersen O. Primary liver cancer and renal cell carcinoma in laundry and dry-cleaning workers in Denmark. Scand J Work Environ Health. 1995;21:293–295. [PubMed: 8553005] [CrossRef]
• Lynge E, Thygesen L. Primary liver cancer among women in laundry and dry-cleaning work in Denmark. Scand J Work Environ Health. 1990;16:108–112. [PubMed: 2353193] [CrossRef]
• Lynge E, Tinnerberg H, Rylander L, et al. Exposure to tetrachloroethylene in dry-cleaning shops in the Nordic countries. Ann Occup Hyg. 2011;55:387–396. [PubMed: 21292730] [CrossRef]
• Ma J, Lessner L, Schreiber J, Carpenter DO. Association between residential proximity to PERC dry-cleaning establishments and kidney cancer in New York City. J Environ Public Health. 2009;2009:183920. [PMC free article: PMC2821751] [PubMed: 20169137]
• Mahle DA, Gearhart JM, Grigsby CC, et al. Age-dependent partition coefficients for a mixture of volatile organic solvents in Sprague-Dawley rats and humans. J Toxicol Environ Health A. 2007;70:1745–1751. [PubMed: 17885931] [CrossRef]
• Malker H, Weiner J. Cancer environment register. Examples of use of register-based epidemiology in occupational health. Arbete Hälsa. 1984;9:1–107. [in Swedish]
• Mallin K. Investigation of a bladder cancer cluster in northwestern Illinois. Am J Epidemiol. 1990;132 Suppl:S96–S106. [PubMed: 2356842]
• Maloney EK, Waxman DJ. trans-Activation of PPARalpha and PPARgamma by structurally diverse environmental chemicals. Toxicol Appl Pharmacol. 1999;161:209–218. [PubMed: 10581215] [CrossRef]
• Mandel JS, McLaughlin JK, Schlehofer B, et al. International renal-cell cancer study. IV. Occupation. Int J Cancer. 1995;61:601–605. [PubMed: 7768630] [CrossRef]
• Marth E. Metabolic changes following oral exposure to tetrachloroethylene in subtoxic concentrations. Arch Toxicol. 1987;60:293–299. [PubMed: 3632354] [CrossRef]
• Marth E, Stünzner D, Köck M, Möse JR. Toxicokinetics of chlorinated hydrocarbons. J Hyg Epidemiol Microbiol Immunol. 1989;33 Suppl:514–520. [PubMed: 2634072]
• Materna BL. Occupational exposure to perchloroethylene in the dry-cleaning industry. Am Ind Hyg Assoc J. 1985;46:268–273. [PubMed: 4003279] [CrossRef]
• Matsushima T, Hayashi M, Matsuoka A, et al. Validation study of the in vitro micronucleus test in a Chinese hamster lung cell line (CHL/IU). Mutagenesis. 1999;14:569–580. [PubMed: 10567032] [CrossRef]
• Mattie DR, Bates GD Jr, Jepson GW, et al. Determination of skin:air partition coefficients for volatile chemicals: experimental method and applications. Fundam Appl Toxicol. 1994;22:51–57. [PubMed: 8125213] [CrossRef]
• Mazzullo M, Grilli S, Lattanzi G, et al. Evidence of DNA binding activity of perchloroethylene. Res Commun Chem Pathol Pharmacol. 1987;58:215–235. [PubMed: 2447621]
• McCarthy MC, Hafner HR, Montzka SA. Background concentrations of 18 air toxics for North America. J Air Waste Manag Assoc. 2006;56:3–11. [PubMed: 16499141] [CrossRef]
• McCarver DG, Hines RN. The ontogeny of human drug-metabolizing enzymes: phase II conjugation enzymes and regulatory mechanisms. J Pharmacol Exp Ther. 2002;300:361–366. [PubMed: 11805192] [CrossRef]
• McCredie M, Stewart JH. Risk factors for kidney cancer in New South Wales. IV. Occupation. Br J Ind Med. 1993;50:349–354. [PMC free article: PMC1061292] [PubMed: 8494775]
• McDermott MJ, Mazor KA, Shost SJ, et al. Tetrachloroethylene (PCE, Perc) levels in residential dry-cleaner buildings in diverse communities in New York City. Environ Health Perspect. 2005;113:1336–1343. [PMC free article: PMC1281276] [PubMed: 16203243] [CrossRef]
• McGoldrick TA, Lock EA, Rodilla V, Hawksworth GM. Renal cysteine conjugate C-S lyase mediated toxicity of halogenated alkenes in primary cultures of human and rat proximal tubular cells. Arch Toxicol. 2003;77:365–370. [PubMed: 12700887] [CrossRef]
• McGraw J, Waller D. Cytochrome P450 variations in different ethnic populations. Expert Opin Drug Metab Toxicol. 2012;8:371–382. [PubMed: 22288606] [CrossRef]
• McKernan LT, Ruder AM, Petersen MR, et al. Biological exposure assessment to tetrachloroethylene for workers in the dry-cleaning industry. Environ Health. 2008;7:12. [PMC free article: PMC2374777] [PubMed: 18412959] [CrossRef]
• McLaughlin JK, Malker HS, Stone BJ, et al. Occupational risks for renal cancer in Sweden. Br J Ind Med. 1987;44:119–123. [PMC free article: PMC1007792] [PubMed: 3814543]
• Mellemgaard A, Engholm G, McLaughlin JK, Olsen JH. Occupational risk factors for renal-cell carcinoma in Denmark. Scand J Work Environ Health. 1994;20:160–165. [PubMed: 7973487] [CrossRef]
• Mennear J, Maronpot R, Boorman G et al. (1986). Toxicologic and carcinogenic effects of inhaled tetrachloroethyhlene in rats and mice. In: New Concepts and Developments in Toxicology. Chambers PL, Gehring P, Sakai F, editors. Amsterdam, the Netherlands: Elsevier, pp. 201–210. [PubMed: 3470175]
• Mersch-Sundermann V, Müller G, Hofmeister A. Examination of mutagenicity of organic microcontaminations of the environment. IV. Communication: the mutagenicity of halogenated aliphatic hydrocarbons with the SOS-chromotest. Zbl Hyg. 1989;189:266–271. [in German] [PubMed: 2697208]
• Miligi L, Seniori Costantini A, Benvenuti A, et al. Occupational exposure to solvents and the risk of lymphomas. Epidemiology. 2006;17:552–561. [PubMed: 16878041] [CrossRef]
• Miligi L, Seniori Costantini A, Crosignani P, et al. Occupational, environmental, and life-style factors associated with the risk of hematolymphopoietic malignancies in women. Am J Ind Med. 1999;36:60–69. [PubMed: 10361588] [CrossRef]
• Milman HA, Story DL, Riccio ES, et al. Rat liver foci and in vitro assays to detect initiating and promoting effects of chlorinated ethanes and ethylenes. Ann N Y Acad Sci. 1988;534:521–530. [PubMed: 3389679] [CrossRef]
• Minder CE, Beer-Porizek V. Cancer mortality of Swiss men by occupation, 1979–1982. Scand J Work Environ Health. 1992;18 Suppl 3:1–27. [PubMed: 1475654]
• Mirabelli D, Kauppinen T. Occupational exposures to carcinogens in Italy: an update of CAREX database. Int J Occup Environ Health. 2005;11:53–63. [PubMed: 15859192]
• Missere M, Giacomini C, Gennari P, et al. 1988[Assessment of exposure to perchloroethylene in dry-cleaning shops][in Italian]G Ital Med Lav 10261–267. [PubMed: 3154908]
• Monster AC. Difference in uptake, elimination, and metabolism in exposure to trichloroethylene, 1,1,1-trichloroethane and tetrachloroethylene. Int Arch Occup Environ Health. 1979;42:311–317. [PubMed: 422272] [CrossRef]
• Monster AC, Boersma G, Steenweg H. Kinetics of tetrachloroethylene in volunteers; influence of exposure concentration and work load. Int Arch Occup Environ Health. 1979;42:303–309. [PubMed: 422271] [CrossRef]
• Monster AC, Houtkooper JM. Estimation of individual uptake of trichloroethylene, 1,1,1-trichloroethane and tetrachloroethylene from biological parameters. Int Arch Occup Environ Health. 1979;42:319–323. [PubMed: 422273] [CrossRef]
• Moon CS, Lee JT, Chun JH, Ikeda M. Use of solvents in industries in Korea: experience in Sinpyeong-Jangrim industrial complex. Int Arch Occup Environ Health. 2001;74:148–152. [PubMed: 11317709] [CrossRef]
• Moran MJ, Zogorski JS, Squillace PJ. Chlorinated solvents in groundwater of the United States. Environ Sci Technol. 2007;41:74–81. [PubMed: 17265929] [CrossRef]
• Morgan JW, Cassady RE. Community cancer assessment in response to long-time exposure to perchlorate and trichloroethylene in drinking water. J Occup Environ Med. 2002;44:616–621. [PubMed: 12134524] [CrossRef]
• Morse KM, Goldberg L. Chlorinated solvent exposures at degreasing operations. Ind Med. 1943;12:706–713.
• Mosely CL (1980). NIOSH Health Hazard Evaluation Report, Motion Pictures Screen Cartoonist, Local 841, New York, NY. HETA 79-42-685. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health .
• Müller C, Franke C, Wagner A, et al. [Development of a rational monitoring strategy for workers exposed to tetrachloroethylene] Z Gesamte Hyg. 1989;35:547–550. [in German] [PubMed: 2555973]
• Murakami K, Horikawa K. The induction of micronuclei in mice hepatocytes and reticulocytes by tetrachloroethylene. Chemosphere. 1995;31:3733–3739. [PubMed: 8528655] [CrossRef]
• Mutti A, Alinovi R, Bergamaschi E, et al. Nephropathies and exposure to perchloroethylene in dry-cleaners. Lancet. 1992;340:189–193. [PubMed: 1353133] [CrossRef]
• Nakai JS, Stathopulos PB, Campbell GL, et al. Jamie S. Nakai, Peter B. Stathopulo. Penetration of chloroform, trichloroethylene, and tetrachloroethylene through human skin. J Toxicol Environ Health A. 1999;58:157–170. [PubMed: 10522647] [CrossRef]
• Nakamura K. Mortality patterns among cleaning workers. Sangyo Igaku. 1985;27:24–37. [PubMed: 4057673] [CrossRef]
• NCI; National Cancer Institute (1977). Bioassay of Tetrachloroethylene for Possible Carcinogenicity (CAS No. 127-18-4) (NCI Tech. Rep. Ser. No. 13; NIH Publ. No. 77–813). Bethesda, MD, USA: US Department of Health, Education, and Welfare.
• Neafsey P, Ginsberg G, Hattis D, et al. Genetic polymorphism in CYP2E1: Population distribution of CYP2E1 activity. J Toxicol Environ Health B Crit Rev. 2009;12:362–388. [PubMed: 20183527] [CrossRef]
• Neta G, Stewart PA, Rajaraman P, et al. Occupational exposure to chlorinated solvents and risks of glioma and meningioma in adults. Occup Environ Med. 2012 [PMC free article: PMC3850418] [PubMed: 22864249] [CrossRef]
• New York State Department of Health (2010). Tetrachloroethylene (perc) exposure and visual contrast sensitivity (VCS) test performance in adults and children residing in buildings with or without a dry-cleaner. Troy, NY, USA .
• NICNAS (2001). Tetrachloroethylene. Priority Existing Chemical Assessment Report No. 15. Australian Government, National Industrial Chemicals Notification and Assessment Scheme. Available online at: http://www.nicnas.gov.au/__data/assets/pdf_file/0020/4376/PEC_15_Tetrachloroethylene_Full_Report_PDF.pdf. Accessed 24 July 2013.
• NIOSH; National Institute for Occupational Safety and Health (1981). National Occupational Health Survey: written communication. WSB-071.25-0.71.54. Cincinnati OH, USA: Department of Health and Human Services.
• NIOSH; National Institute for Occupational Safety and Health (1994). Pocket Guide to Chemical Hazards. Cincinnati, OH, USA: No. (DHHS Publ. 94-116), pp. 314–315.
• NIOSH; National Institute for Occupational Safety and Health (2013). National occupational exposure survey. Available at: http://www.cdc.gov/noes/. Accessed 26 July 2013.
• Novick RM, Elfarra AA. Purification and characterization of flavin-containing monooxygenase isoform 3 from rat kidney microsomes. Drug Metab Dispos. 2008;36:2468–2474. [PMC free article: PMC2585157] [PubMed: 18775983] [CrossRef]
• NRC; National Research Council (2009). Contaminated water supplies at Camp Lejeune: assessing potential health effects. In: Board on Environmental Studies and Toxicity, 328. Washington DC, USA: National Academics Press. Available online at: http://www.nap.edu/catalog.php?record_id=12618. Accessed 22 October 2013. [PubMed: 25009942]
• NRC; National Research Council (2010). Review of the Environmental Protection Agency's draft IRIS assessment of tetrachloroethylene. Washington, DC: National Academies Press. [PubMed: 25032380]
• NTP. National Toxicology Program. Carcinogenesis Studies of Pentachloroethane (CAS No. 76–01–7) in F344/N Rats and B6C3F1 Mice (Gavage Study). Natl Toxicol Program Tech Rep Ser. 1983;232:1–149. [PubMed: 12778204]
• NTP. National Toxicology Program. Toxicology and Carcinogenesis Studies of Tetrachloroethylene (Perchloroethylene) (CAS No. 127–18–4) in F344/N Rats and B6C3F1 Mice (Inhalation Studies). Natl Toxicol Program Tech Rep Ser. 1986;311:1–197. [PubMed: 12748718]
• NTP. National Toxicology Program. Toxicology and Carcinogenesis Studies of d-Limonene (CAS No. 5989-27-5) in F344/N Rats and B6C3F1 Mice (Gavage Studies). Natl Toxicol Program Tech Rep Ser. 1990;347:1–165. [PubMed: 12704437]
• NTP; National Toxicology Program (2012). Databases and Searches. Available online at: http://ntp.niehs.nih.gov. Accessed August 2013.
• O’Neil MJ, Heckelman PE, Roman CB (2006). The Merck Index.14th Ed. Whitehouse Station, NJ, USA: Merck & Co., Monograph Number 09639.
• Odum J, Green T, Foster JR, Hext PM. The role of trichloracetic acid and peroxisome proliferation in the differences in carcinogenicity of perchloroethylene in the mouse and rat. Toxicol Appl Pharmacol. 1988;92:103–112. [PubMed: 3341020] [CrossRef]
• Ohtsuki T, Sato K, Koizumi A, et al. Limited capacity of humans to metabolize tetrachloroethylene. Int Arch Occup Environ Health. 1983;51:381–390. [PubMed: 6862652] [CrossRef]
• Ohura T, Amagai T, Senga Y, Fusaya M. Organic air pollutants inside and outside residences in Shimizu, Japan: levels, sources and risks. Sci Total Environ. 2006;366:485–499. [PubMed: 16298419] [CrossRef]
• Ojajärvi A, Partanen T, Ahlbom A, et al. Risk of pancreatic cancer in workers exposed to chlorinated hydrocarbon solvents and related compounds: a meta-analysis. Am J Epidemiol. 2001;153:841–850. [PubMed: 11323314] [CrossRef]
• Okada Y, Nakagoshi A, Tsurukawa M, et al. Environmental risk assessment and concentration trend of atmospheric volatile organic compounds in Hyogo Prefecture, Japan. Environ Sci Pollut Res Int. 2012;19:201–213. [PMC free article: PMC3249200] [PubMed: 21717170] [CrossRef]
• Okawa MT, Coye MJ (1982). NIOSH Health Hazard Evaluation Report, Film Processing Industry, Hollywood, CA. HETA 80-144-1109. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Opdam JJ. Intra and interindividual variability in the kinetics of a poorly and highly metabolising solvent. Br J Ind Med. 1989;46:831–845. [PMC free article: PMC1009879] [PubMed: 2611156]
• Pannier R, Hübner G, Schulz G. 1986[Results of biologic exposure tests in relation to passive dosimetry measurements of room air concentrations in occupational exposure to tetrachloroethane in chemical dry-cleaning establishments][in German]Z Gesamte Hyg 32297–300. [PubMed: 3751167]
• Paulu C, Aschengrau A, Ozonoff D. Tetrachloroethylene-contaminated drinking water in Massachusetts and the risk of colon-rectum, lung, and other cancers. Environ Health Perspect. 1999;107:265–271. [PMC free article: PMC1566514] [PubMed: 10090704] [CrossRef]
• Pegg DG, Zempel JA, Braun WH, Watanabe PG. Disposition of tetrachloro(14C)ethylene following oral and inhalation exposure in rats. Toxicol Appl Pharmacol. 1979;51:465–474. [PubMed: 538758] [CrossRef]
• Pellizzari ED, Hartwell TD, Harris BS 3rd, et al. Purgeable organic compounds in mother’s milk. Bull Environ Contam Toxicol. 1982;28:322–328. [PubMed: 7082873] [CrossRef]
• Pereira MA. Carcinogenic activity of dichloroacetic acid and trichloroacetic acid in the liver of female B6C3F1 mice. Fundam Appl Toxicol. 1996;31:192–199. [PubMed: 8789785] [CrossRef]
• Perocco P, Bolognesi S, Alberghini W. Toxic activity of seventeen industrial solvents and halogenated compounds on human lymphocytes cultured in vitro. Toxicol Lett. 1983;16:69–75. [PubMed: 6836616] [CrossRef]
• Pesch B, Haerting J, Ranft U, et al. MURC Study Group. Occupational risk factors for renal cell carcinoma: agent-specific results from a case-control study in Germany. MURC Study Group. Multicenter urothelial and renal cancer study. Int J Epidemiol. 2000;29:1014–1024. b. [PubMed: 11101542] [CrossRef]
• Pesch B, Haerting J, Ranft U, et al. MURC Study Group. Occupational risk factors for urothelial carcinoma: agent-specific results from a case-control study in Germany. MURC Study Group. Multicenter urothelial and renal cancer study. Int J Epidemiol. 2000;29:238–247. a. [PubMed: 10817119] [CrossRef]
• Petreas MX, Rappaport SM, Materna BL, et al. Mixed-exhaled air measurements to assess exposure to tetrachloroethylene in dry-cleaners. J Expo Anal Environ Epidemiol. 1992 Suppl 1:25–39.
• Pezzagno G, Imbriani M, Ghittori S, Capodaglio E. Urinary concentration, environmental concentration, and respiratory uptake of some solvents: effect of the work load. Am Ind Hyg Assoc J. 1988;49:546–552. [PubMed: 3195471] [CrossRef]
• Philip BK, Mumtaz MM, Latendresse JR, Mehendale HM. Impact of repeated exposure on toxicity of perchloroethylene in Swiss Webster mice. Toxicology. 2007;232:1–14. [PubMed: 17267091] [CrossRef]
• Poet TS, Weitz KK, Gies RA, et al. PBPK modeling of the percutaneous absorption of perchloroethylene from a soil matrix in rats and humans. Toxicol Sci. 2002;67:17–31. [PubMed: 11961212] [CrossRef]
• Popp W, Müller G, Baltes-Schmitz B, et al. Concentrations of tetrachloroethene in blood and trichloroacetic acid in urine in workers and neighbours of dry-cleaning shops. Int Arch Occup Environ Health. 1992;63:393–395. [PubMed: 1544687] [CrossRef]
• Potter CL, Chang LW, DeAngelo AB, Daniel FB. Effects of four trihalomethanes on DNA strand breaks, renal hyaline droplet formation and serum testosterone in male F-344 rats. Cancer Lett. 1996;106:235–242. [PubMed: 8844978] [CrossRef]
• Pratt GC, Palmer K, Wu CY, et al. An assessment of air toxics in Minnesota. Environ Health Perspect. 2000;108:815–825. [PMC free article: PMC2556921] [PubMed: 11017885] [CrossRef]
• Price PJ, Hassett CM, Mansfield JI. Transforming activities of trichloroethylene and proposed industrial alternatives. In Vitro. 1978;14:290–293. [PubMed: 669729] [CrossRef]
• Pryor P (1977). NIOSH Health Hazard Evaluation Report, McCourt Label Company, Bradford, PA. HETA 77-84-450. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Pryor P (1985). NIOSH Health Hazard Evaluation Report, Denver Laundry and Dry Cleaning, Denver, CO. HETA 84-340-1606. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health.
• Pukkala E, Martinsen JI, Lynge E, et al. Occupation and cancer - follow-up of 15 million people in five Nordic countries. Acta Oncol. 2009;48:646–790. [PubMed: 19925375] [CrossRef]
• Radican L, Blair A, Stewart P, Wartenberg D. Mortality of aircraft maintenance workers exposed to trichloroethylene and other hydrocarbons and chemicals: extended follow-up. J Occup Environ Med. 2008;50:1306–1319. [PMC free article: PMC2763375] [PubMed: 19001957] [CrossRef]
• Räisänen J, Niemelä R, Rosenberg C. Tetrachloroethylene emissions and exposure in dry-cleaning. J Air Waste Manag Assoc. 2001;51:1671–1675. [PubMed: 15666472] [CrossRef]
• Ramírez N, Cuadras A, Rovira E, et al. Chronic risk assessment of exposure to volatile organic compounds in the atmosphere near the largest Mediterranean industrial site. Environ Int. 2012;39:200–209. [PubMed: 22208760] [CrossRef]
• Rampy LW, Quast JF, Leong BKJ, Gehring PJ (1977). Results of long-term inhalation toxicity studies on rats of 1,1,1-trichloroethane and perchloroethylene formulations (Abstract). New York, USA: Academic Press: Proceedings of the First International Congress on Toxicology, 1977, pp. 27.
• Rantala K, Riipinen H, Anttila A (1992). [Exposure at work: 22. Halogenated hydrocarbons] [in Finnish]. Helsinki, Finland: Finnish Institute of Occupational Health - Finnish Work Environment Fund, pp. 1–40.
• Rao HV, Brown DR. A physiologically based pharmacokinetic assessment of tetrachloroethylene in groundwater for a bathing and showering determination. Risk Anal. 1993;13:37–49. [PubMed: 8451459] [CrossRef]
• Rappaport SM, Kupper LL. Variability of environmental exposures to volatile organic compounds. J Expo Anal Environ Epidemiol. 2004;14:92–107. [PubMed: 14726948] [CrossRef]
• Rastkari N, Yunesian M, Ahmadkhaniha R. Exposure assessment to trichloroethylene and perchloroethylene for workers in the dry-cleaning industry. Bull Environ Contam Toxicol. 2011;86:363–367. [PubMed: 21416139] [CrossRef]
• Reichert D. Biological actions and interactions of tetrachloroethylene. Mutat Res. 1983;123:411–429. [PubMed: 6358882] [CrossRef]
• Reichert D, Neudecker T, Spengler U, Henschler D. Mutagenicity of dichloroacetylene and its degradation products trichloroacetyl chloride, trichloroacryloyl chloride and hexachlorobutadiene. Mutat Res. 1983;117:21–29. [PubMed: 6339907] [CrossRef]
• Reitz RH, Gargas ML, Mendrala AL, Schumann AM. In vivo and in vitro studies of perchloroethylene metabolism for physiologically based pharmacokinetic modeling in rats, mice, and humans. Toxicol Appl Pharmacol. 1996;136:289–306. [PubMed: 8619237] [CrossRef]
• Rich AL (2011). Air emissions from natural gas exploration and mining in the Barnett shale geologic reservoir. Arlington, TX, USA: University of Texas, Unpublished dissertation.
• Riihimäki V, Pfäffli P. Percutaneous absorption of solvent vapors in man. Scand J Work Environ Health. 1978;4:73–85. [PubMed: 644269] [CrossRef]
• Ring JA, Ghabrial H, Ching MS, et al. Fetal hepatic drug elimination. Pharmacol Ther. 1999;84:429–445. [PubMed: 10665839] [CrossRef]
• Ripp SL, Overby LH, Philpot RM, Elfarra AA. Oxidation of cysteine S-conjugates by rabbit liver microsomes and cDNA-expressed flavin-containing mono-oxygenases: studies with S-(1,2-dichlorovinyl)-L-cysteine, S-(1,2,2-trichlorovinyl)-L-cysteine, S-allyl-L-cysteine, and S-benzyl-L-cysteine. Mol Pharmacol. 1997;51:507–515. [PubMed: 9058607]
• Rodilla V, Benzie AA, Veitch JM, et al. Glutathione S-transferases in human renal cortex and neoplastic tissue: enzymatic activity, isoenzyme profile and immunohistochemical localization. Xenobiotica. 1998;28:443–456. [PubMed: 9622847] [CrossRef]
• Roldán-Arjona T, García-Pedrajas MD, Luque-Romero FL, et al. An association between mutagenicity of the Ara test of Salmonella typhimurium and carcinogenicity in rodents for 16 halogenated aliphatic hydrocarbons. Mutagenesis. 1991;6:199–205. [PubMed: 1881351] [CrossRef]
• Rosengren LE, Kjellstrand P, Haglid KG. Tetrachloroethylene: levels of DNA and S-100 in the gerbil CNS after chronic exposure. Neurobehav Toxicol Teratol. 1986;8:201–206. [PubMed: 3713968]
• Ruder AM, Ward EM, Brown DP. Cancer mortality in female and male dry-cleaning workers. J Occup Med. 1994;36:867–874. [PubMed: 7807267]
• Ruder AM, Ward EM, Brown DP. Mortality in dry-cleaning workers: an update. Am J Ind Med. 2001;39:121–132. [PubMed: 11170155] [CrossRef]
• Ruder AM, Yiin JH, Waters MA, et al. Brain Cancer Collaborative Study Group. The Upper Midwest Health Study: gliomas and occupational exposure to chlorinated solvents. Occup Environ Med. 2013;70:73–80. [PMC free article: PMC4563805] [PubMed: 23104734] [CrossRef]
• Sabel GV, Clark TP. Volatile organic compounds as indicators of municipal solid waste leachate contamination. Waste Manag Res. 1984;2:119–130.
• Sabolić I, Asif AR, Budach WE, et al. Gender differences in kidney function. Pflugers Arch. 2007;455:397–429. [PubMed: 17638010] [CrossRef]
• Sadtler Research Laboratories (1980). 1980 Cumulative Index. Philadelphia, PA.
• Sanchez IM, Bull RJ. Early induction of reparative hyperplasia in the liver of B6C3F1 mice treated with dichloroacetate and trichloroacetate. Toxicology. 1990;64:33–46. [PubMed: 2219131] [CrossRef]
• Sandhu SS, Ma TH, Peng Y, Zhou XD. Clastogenicity evaluation of seven chemicals commonly found at hazardous industrial waste sites. Mutat Res. 1989;224:437–445. [PubMed: 2586542] [CrossRef]
• Sato A, Nakajima T. A vial-equilibration method to evaluate the drug-metabolizing enzyme activity for volatile hydrocarbons. Toxicol Appl Pharmacol. 1979;47:41–46. [PubMed: 34248] [CrossRef]
• Savolainen H, Pfäffli P, Tengén M, Vainio H. Biochemical and behavioural effects of inhalation exposure to tetrachlorethylene and dichlormethane. J Neuropathol Exp Neurol. 1977;36:941–949. [PubMed: 925719] [CrossRef]
• Schairer LA, Sautkulis RC. Detection of ambient levels of mutagenic atmospheric pollutants with the higher plant. Tradescantia Environ Mutag Carcinog Plant Biol. 1982;2:154–194.
• Schoenberg JB, Stemhagen A, Mogielnicki AP, et al. Case-control study of bladder cancer in New Jersey. I. Occupational exposures in white males. J Natl Cancer Inst. 1984;72:973–981. [PubMed: 6585596]
• Schreiber JS. Predicted infant exposure to tetrachloroethene in human breastmilk. Risk Anal. 1993;13:515–524. [PubMed: 8259441] [CrossRef]
• Schreiber JS, editor (1997). Transport of organic chemicals to breast milk: Tetrachloroethene case study. Washington, DC, USA: Taylor and Francis.
• Schreiber JS, Hudnell HK, Geller AM, et al. Apartment residents’ and day care workers’ exposures to tetrachloroethylene and deficits in visual contrast sensitivity. Environ Health Perspect. 2002;110:655–664. [PMC free article: PMC1240911] [PubMed: 12117642] [CrossRef]
• Schumann AM, Quast JF, Watanabe PG. The pharmacokinetics and macromolecular interactions of perchloroethylene in mice and rats as related to oncogenicity. Toxicol Appl Pharmacol. 1980;55:207–219. [PubMed: 7423514] [CrossRef]
• Seeber A. Neurobehavioral toxicity of long-term exposure to tetrachloroethylene. Neurotoxicol Teratol. 1989;11:579–583. [PubMed: 2626148] [CrossRef]
• Seidel HJ, Barthel E, Zinser D. The hematopoietic stem cell compartments in mice during and after long-term inhalation of three doses of benzene. Exp Hematol. 1989;17:300–303. a. [PubMed: 2917624]
• Seidel HJ, Beyvers G, Pape M, Barthel E. The influence of benzene on the erythroid cell system in mice. Exp Hematol. 1989;17:760–764. b. [PubMed: 2753084]
• Seidel HJ, Weber L, Barthel E. Hematological toxicity of tetrachloroethylene in mice. Arch Toxicol. 1992;66:228–230. [PubMed: 1497490] [CrossRef]
• Seidler A, Möhner M, Berger J, et al. Solvent exposure and malignant lymphoma: a population-based case-control study in Germany. J Occup Med Toxicol. 2007;2:2. [PMC free article: PMC1851965] [PubMed: 17407545] [CrossRef]
• Seiji K, Jin C, Watanabe T, et al. Sister chromatid exchanges in peripheral lymphocytes of workers exposed to benzene, trichloroethylene, or tetrachloroethylene, with reference to smoking habits. Int Arch Occup Environ Health. 1990;62:171–176. [PubMed: 2323835] [CrossRef]
• Sekine T, Miyazaki H, Endou H. Molecular physiology of renal organic anion transporters. Am J Physiol Renal Physiol. 2006;290:F251–F261. [PubMed: 16403838] [CrossRef]
• Seldén AI, Ahlborg G Jr. Cancer morbidity in Swedish dry-cleaners and laundry workers: historically prospective cohort study. Int Arch Occup Environ Health. 2011;84:435–443. [PMC free article: PMC3058547] [PubMed: 20886350] [CrossRef]
• Sexton K, Adgate JL, Church TR, et al. Children’s exposure to volatile organic compounds as determined by longitudinal measurements in blood. Environ Health Perspect. 2005;113:342–349. [PMC free article: PMC1253763] [PubMed: 15743726] [CrossRef]
• Shafer TJ, Bushnell PJ, Benignus VA, Woodward JJ. Perturbation of voltage-sensitive Ca2+ channel function by volatile organic solvents. J Pharmacol Exp Ther. 2005;315:1109–1118. [PubMed: 16109744] [CrossRef]
• Shimada T, Swanson AF, Leber P, Williams GM. Activities of chlorinated ethane and ethylene compounds in the Salmonella/rat microsome mutagenesis and rat hepatocyte/DNA repair assays under vapor phase exposure conditions. Cell Biol Toxicol. 1985;1:159–179. [PubMed: 3917197] [CrossRef]
• Shipman AJ, Whim BP. Occupational exposure to trichloroethylene in metal cleaning processes and to tetrachloroethylene in the drycleaning industry in the U.K. Ann Occup Hyg. 1980;23:197–204. [PubMed: 7436231] [CrossRef]
• Shrivastav BB, Narahashi T, Kitz RJ, Roberts JD. Mode of action of trichloroethylene on squid axon membranes. J Pharmacol Exp Ther. 1976;199:179–188. [PubMed: 978477]
• Siemiatycki J, editor (1991). Risk factors for cancer in the workplace. Boca Raton, FL: CRC Press.
• Siemiatycki J, Dewar R, Nadon L, Gérin M. Occupational risk factors for bladder cancer: results from a case-control study in Montreal, Quebec, Canada. Am J Epidemiol. 1994;140:1061–1080. [PubMed: 7998589]
• Silverman DT, Levin LI, Hoover RN. Occupational risks of bladder cancer in the United States: II Nonwhite men. J Natl Cancer Inst. 1989;81:1480–1483. [PubMed: 2778835] [CrossRef]
• Silverman DT, Levin LI, Hoover RN. Occupational risks of bladder cancer among white women in the United States. Am J Epidemiol. 1990;132:453–461. [PubMed: 2389750]
• Skender L, Karacić V, Bosner B, Prpić-Majić D. Assessment of exposure to trichloroethylene and tetrachloroethylene in the population of Zagreb, Croatia. Int Arch Occup Environ Health. 1993;65 Suppl:S163–S165. [PubMed: 8406918] [CrossRef]
• Skender LJ, Karacić V, Prpić-Majić D. A comparative study of human levels of trichloroethylene and tetrachloroethylene after occupational exposure. Arch Environ Health. 1991;46:174–178. [PubMed: 2039273] [CrossRef]
• Sofuni T, Hayashi M, Matsuoka A, et al. 1985[Mutagenicity tests on organic chemical contaminants in city water and related compounds. II. Chromosome aberration tests in cultured mammalian cells][in Japanese]Eisei Shikenjo Hokoku 10364–75. [PubMed: 3830315]
• Sonnenfeld N, Hertz-Picciotto I, Kaye WE. Tetrachloroethylene in drinking water and birth outcomes at the US Marine Corps Base at Camp Lejeune, North Carolina. Am J Epidemiol. 2001;154:902–908. [PubMed: 11700244] [CrossRef]
• Spinatonda G, Colombo R, Capodaglio EM, et al. [Processes of speech production: Application in a group of subjects chronically exposed to organic solvents (II).] G Ital Med Lav Ergon. 1997;19:85–88. [in Italian] [PubMed: 9463050]
• State Coalition for Remediation of Drycleaners. (2009). Chemicals Used in Drycleaning Operations. Available at: http://www.drycleancoalition.org/chemicals/ChemicalsUsedInDrycleaningOperations.pdf.
• Stauber AJ, Bull RJ. Differences in phenotype and cell replicative behavior of hepatic tumors induced by dichloroacetate (DCA) and trichloroacetate (TCA). Toxicol Appl Pharmacol. 1997;144:235–246. [PubMed: 9194407] [CrossRef]
• Steineck G, Plato N, Gerhardsson M, et al. Increased risk of urothelial cancer in Stockholm during 1985–87 after exposure to benzene and exhausts. Int J Cancer. 1990;45:1012–1017. [PubMed: 1693598] [CrossRef]
• Steinsvåg K, Bråtveit M, Moen BE. Exposure to carcinogens for defined job categories in Norway’s offshore petroleum industry, 1970 to 2005. Occup Environ Med. 2007;64:250–258. [PMC free article: PMC2078458] [PubMed: 17043075] [CrossRef]
• Stevens JL, Robbins JD, Byrd RA. A purified cysteine conjugate beta-lyase from rat kidney cytosol. Requirement for an alpha-keto acid or an amino acid oxidase for activity and identity with soluble glutamine transaminase K. J Biol Chem. 1986;261:15529–15537. [PubMed: 3782077]
• Stewart RD, Baretta ED, Dodd HC, Torkelson TR. Experimental human exposure to tetrachloroethylene. Arch Environ Health. 1970;20:225–229. [PubMed: 5411393] [CrossRef]
• Stewart RD, Dodd HC. Absorption of carbon tetrachloride, trichloroethylene, tetrachloroethylene, methylene chloride, and 1,1,1-trichloroethane through the human skin. Am Ind Hyg Assoc J. 1964;25:439–446. [PubMed: 14209666] [CrossRef]
• Stewart RD, Hake CL et al. (1977). Effects of perchloroethylene/drug interaction on behavior and neurological function. Milwaukee, WI, Allen-Bradley Medical Science Laboratory.
• Storm JE, Mazor KA, Aldous KM, et al. Visual contrast sensitivity in children exposed to tetrachloroethylene. Arch Environ Occup Health. 2011;66:166–177. [Erratum in: Arch Environ Occup Health, 66(4):250. [PubMed: 21864105] [CrossRef]
• Struwe M, Zeller A, Singer T, Gocke E. Possibility of methodical bias in analysis of comet assay studies: Re: DNA damage detected by the alkaline comet assay in the liver of mice after oral administration of tetrachloroethylene. (Mutagenesis, 25, 133–138, 2010). Mutagenesis. 2011;26:473–474. [PubMed: 21389072] [CrossRef]
• Suarez L, Weiss NS, Martin J. Primary liver cancer death and occupation in Texas. Am J Ind Med. 1989;15:167–175. [PubMed: 2729281] [CrossRef]
• Swanson GM, Burns PB. Cancer incidence among women in the workplace: a study of the association between occupation and industry and 11 cancer sites. J Occup Environ Med. 1995;37:282–287. [PubMed: 7796194] [CrossRef]
• Szadkowski D, Körber M. 1969[Liver function tests in solvent-exposed workers in the metal processing industry][in German]Int Arch Arbeitsmed 25323–337. [PubMed: 5370816]
• Tao L, Kramer PM, Ge R, Pereira MA. Effect of dichloroacetic acid and trichloroacetic acid on DNA methylation in liver and tumors of female B6C3F1 mice. Toxicol Sci. 1998;43:139–144. [PubMed: 9710955] [CrossRef]
• Tao L, Wang W, Li L, et al. Effect of dibromoacetic acid on DNA methylation, glycogen accumulation, and peroxisome proliferation in mouse and rat liver. Toxicol Sci. 2004;82:62–69. [PubMed: 15342954] [CrossRef]
• Tao L, Yang S, Xie M, et al. Hypomethylation and overexpression of c-jun and c-myc protooncogenes and increased DNA methyltransferase activity in dichloroacetic and trichloroacetic acid-promoted mouse liver tumors. Cancer Lett. 2000;158:185–193. [PubMed: 10960769] [CrossRef]
• Tateishi M, Suzuki S, Shimizu H. Cysteine conjugate beta-lyase in rat liver. A novel enzyme catalyzing formation of thiol-containing metabolites of drugs. J Biol Chem. 1978;253:8854–8859. [PubMed: 721818]
• Tateishi T, Nakura H, Asoh M, et al. A comparison of hepatic cytochrome P450 protein expression between infancy and postinfancy. Life Sci. 1997;61:2567–2574. [PubMed: 9416779] [CrossRef]
• Tharr D, Donahue M (1980). NIOSH Health Hazard Evaluation Report, Cobo Laboratories Inc., Lakewood & Arvada, CO. HETA 79-80-746. Cincinnati, OH, USA: United States National Institute for Occupational Safetyand Health.
• Theiss JC, Stoner GD, Shimkin MB, Weisburger EK. Test for carcinogenicity of organic contaminants of United States drinking waters by pulmonary tumor response in strain A mice. Cancer Res. 1977;37:2717–2720. [PubMed: 872098]
• Toraason M, Butler MA, Ruder A, et al. Effect of perchloroethylene, smoking, and race on oxidative DNA damage in female dry cleaners. Mutat Res. 2003;539:9–18. [PubMed: 12948810] [CrossRef]
• Toraason M, Clark J, Dankovic D, et al. Oxidative stress and DNA damage in Fischer rats following acute exposure to trichloroethylene or perchloroethylene. Toxicology. 1999;138:43–53. [PubMed: 10566590] [CrossRef]
• Travier N, Gridley G, De Roos AJ, et al. Cancer incidence of dry-cleaning, laundry and ironing workers in Sweden. Scand J Work Environ Health. 2002;28:341–348. [PubMed: 12432988] [CrossRef]
• Trevisan A, Maccà I, Rui F, et al. Kidney and liver biomakers in female dry-cleaning workers exposed to perchloroethylene. Biomarkers. 2000;5:399–409. [PubMed: 23898811] [CrossRef]
• Tsuruta H. Skin absorption of organic solvent vapors in nude mice in vivo. Ind Health. 1989;27:37–47. [PubMed: 2745160] [CrossRef]
• Tu AS, Murray TA, Hatch KM, et al. In vitro transformation of BALB/c-3T3 cells by chlorinated ethanes and ethylenes. Cancer Lett. 1985;28:85–92. [PubMed: 4027960] [CrossRef]
• Tucker JD, Sorensen KJ, Ruder AM, et al. 2011Cytogenetic analysis of an exposed-referent study: perchloroethylene-exposed dry cleaners compared to unexposed laundry workers. Environ Health 1016PMID:21392400 10.1186/1476-069X-10-16 . [PMC free article: PMC3062579] [PubMed: 21392400] [CrossRef]
• TURI (2006). Perchloroethylene. In: Five Chemical Alternatives Assessment Study. Toxics Use Reduction Institute.
• Tuttle TC, Wood GD, Crether CB et al. (1977). A Behavioural and Neurological Evaluation of Dry-cleaners Exposed to Perchloroethylene. US DHEW/NIOSH Report No. 77–214.
• Tzeng HF, Blackburn AC, Board PG, Anders MW. Polymorphism- and species-dependent inactivation of glutathione transferase zeta by dichloroacetate. Chem Res Toxicol. 2000;13:231–236. [PubMed: 10775321] [CrossRef]
• Urban TJ, Sebro R, Hurowitz EH, et al. Functional genomics of membrane transporters in human populations. Genome Res. 2006;16:223–230. [PMC free article: PMC1361718] [PubMed: 16354753] [CrossRef]
• Uttamsingh V, Anders MW. Acylase-catalyzed deacetylation of haloalkene-derived mercapturates. Chem Res Toxicol. 1999;12:937–942. [PubMed: 10525269] [CrossRef]
• Vainio H, Waters MD, Norppa H. Mutagenicity of selected organic solvents. Scand J Work Environ Health. 1985;11 Suppl 1:75–82. [PubMed: 3906872]
• Valencia R, Mason JM, Woodruff RC, Zimmering S. Chemical mutagenesis testing in Drosophila. III. Results of 48 coded compounds tested for the National Toxicology Program. Environ Mutagen. 1985;7:325–348. [PubMed: 3930234] [CrossRef]
• Vamvakas S, Dekant W, Berthold K, et al. Enzymatic transformation of mercapturic acids derived from halogenated alkenes to reactive and mutagenic intermediates. Biochem Pharmacol. 1987;36:2741–2748. [PubMed: 3307787] [CrossRef]
• Vamvakas S, Dekant W, Henschler D. Genotoxicity of haloalkene and haloalkane glutathione S-conjugates in porcine kidney cells. Toxicol In Vitro. 1989;3:151–156. b. [PubMed: 20702313] [CrossRef]
• Vamvakas S, Dekant W, Henschler D. Assessment of unscheduled DNA synthesis in a cultured line of renal epithelial cells exposed to cysteine S-conjugates of haloalkenes and haloalkanes. Mutat Res. 1989;222:329–335. c. [PubMed: 2704384] [CrossRef]
• Vamvakas S, Herkenhoff M, Dekant W, Henschler D. Mutagenicity of tetrachloroethene in the Ames test–metabolic activation by conjugation with glutathione. J Biochem Toxicol. 1989;4:21–27. a. [PubMed: 2671372] [CrossRef]
• Vamvakas S, Köchling A, Berthold K, Dekant W. Cytotoxicity of cysteine S-conjugates: structure-activity relationships. Chem Biol Interact. 1989;71:79–90. d. [PubMed: 2776234] [CrossRef]
• van der Tuin J (1979). [Perchloroethylene in a Dry-cleaning Service] (Report F1647). Rijswyk, the Netherlands: Institute of Environmental Hygiene and Health Engineering/Dutch Organization for Applied Research (in Dutch).
• van der Tuin J, Hoevers W (1977a) [Perchloroethylene in a Dry-cleaning Service] (Report F1560). Rijswyk, the Netherlands: Institute of Environmental Hygiene and Health Engineering/Dutch Organization for Applied Research (in Dutch).
• van der Tuin J, Hoevers W (1977b). Perchloroethylene in a Dry-cleaning Service (Report F1590). Rijswyk, the Netherlands: Institute of Environmental Hygiene and Health Engineering/Dutch Organization for Applied Research (in Dutch).
• Van Duuren BL, Goldschmidt BM, Loewengart G, et al. Carcinogenicity of halogenated olefinic and aliphatic hydrocarbons in mice. J Natl Cancer Inst. 1979;63:1433–1439. [PubMed: 292813]
• Van Duuren BL, Kline SA, Melchionne S, Seidman I. Chemical structure and carcinogenicity relationships of some chloroalkene oxides and their parent olefins. Cancer Res. 1983;43:159–162. [PubMed: 6847764]
• Vartiainen T, Pukkala E, Rienoja T, et al. Population exposure to tri- and tetrachloroethene and cancer risk: Two cases of drinking water pollution. Chemosphere. 1993;27:1171–1181. [CrossRef]
• Vaughan TL, Stewart PA, Davis S, Thomas DB. Work in dry-cleaning and the incidence of cancer of the oral cavity, larynx, and oesophagus. Occup Environ Med. 1997;54:692–695. [PMC free article: PMC1128846] [PubMed: 9423585] [CrossRef]
• Vedrina-Dragojević I, Dragojević D. Trichloroethene and tetrachloroethene in ground waters of Zagreb, Croatia. Sci Total Environ. 1997;203:253–259. [PubMed: 9260311] [CrossRef]
• Verplanke AJ, Leummens MH, Herber RF. Occupational exposure to tetrachloroethene and its effects on the kidneys. J Occup Environ Med. 1999;41:11–16. [PubMed: 9924715] [CrossRef]
• Vieira V, Aschengrau A, Ozonoff D. Impact of tetrachloroethylene-contaminated drinking water on the risk of breast cancer: using a dose model to assess exposure in a case-control study. Environ Health. 2005;4:3. [PMC free article: PMC554766] [PubMed: 15733317] [CrossRef]
• Vizcaya D, Christensen KY, Lavoué J, Siemiatycki J. Risk of lung cancer associated with six types of chlorinated solvents: results from two case-control studies in Montreal, Canada. Occup Environ Med. 2013;70:81–85. [PubMed: 23104733] [CrossRef]
• Völkel W, Friedewald M, Lederer E, et al. Biotransformation of perchloroethene: dose-dependent excretion of trichloroacetic acid, dichloroacetic acid, and N-acetyl-S-(trichlorovinyl)-L-cysteine in rats and humans after inhalation. Toxicol Appl Pharmacol. 1998;153:20–27. [PubMed: 9875296] [CrossRef]
• Völkel W, Pähler A, Dekant W. Gas chromatography-negative ion chemical ionization mass spectrometry as a powerful tool for the detection of mercapturic acids and DNA and protein adducts as biomarkers of exposure to halogenated olefins. J Chromatogr A. 1999;847:35–46. [PubMed: 10431350] [CrossRef]
• von Grote J, Hürlimann C, Scheringer M, Hungerbühler K. Reduction of occupational exposure to perchloroethylene and trichloroethylene in metal degreasing over the last 30 years: influences of technology innovation and legislation. J Expo Anal Environ Epidemiol. 2003;13:325–340. [PubMed: 12973361] [CrossRef]
• von Grote J, Hürlimann C, Scheringer M, Hungerbühler K. Assessing occupational exposure to perchloroethylene in dry-cleaning. J Occup Environ Hyg. 2006;3:606–619. [PubMed: 17086665] [CrossRef]
• Vyskocil A, Emminger S, Tejral J, et al. Study on kidney function in female workers exposed to perchlorethylene. Hum Exp Toxicol. 1990;9:377–380. [PubMed: 2271228] [CrossRef]
• Walgren JE, Kurtz DT, McMillan JM. The effect of the trichloroethylene metabolites trichloroacetate and dichloroacetate on peroxisome proliferation and DNA synthesis in cultured human hepatocytes. Cell Biol Toxicol. 2000;16:257–273. [PubMed: 11101007] [CrossRef]
• Walker JT, Burnett CA, Lalich NR, et al. Cancer mortality among laundry and dry-cleaning workers. Am J Ind Med. 1997;32:614–619. [PubMed: 9358918] [CrossRef]
• Walles SAS. Induction of single-strand breaks in DNA of mice by trichloroethylene and tetrachloroethylene. Toxicol Lett. 1986;31:31–35. [PubMed: 3715914] [CrossRef]
• Wang FI, Kuo ML, Shun CT, et al. Chronic toxicity of a mixture of chlorinated alkanes and alkenes in ICR mice. J Toxicol Environ Health A. 2002;65:279–291. [PubMed: 11911491] [CrossRef]
• Wang JL, Chen WL, Tsai SY, et al. An in vitro model for evaluation of vaporous toxicity of trichloroethylene and tetrachloroethylene to CHO-K1 cells. Chem Biol Interact. 2001;137:139–154. [PubMed: 11551530] [CrossRef]
• Wang S, Karlsson JE, Kyrklund T, Haglid K. Perchloroethylene-induced reduction in glial and neuronal cell marker proteins in rat brain. Pharmacol Toxicol. 1993;72:273–278. [PubMed: 8372046] [CrossRef]
• Ward PM. Brown and black grease suitability for incorporation into feeds and suitability for biofuels. J Food Prot. 2012;75:731–737. [PubMed: 22488062] [CrossRef]
• Weast RC, Astle MJ (1985). CRC Handbook of Data on Organic Compounds, Boca Raton, FL: CRC Press.
• Weisburger EK. Carcinogenicity studies on halogenated hydrocarbons. Environ Health Perspect. 1977;21:7–16. [PMC free article: PMC1475344] [PubMed: 206428] [CrossRef]
• Weisel CP, Alimokhtari S, Sanders PF. Indoor air VOC concentrations in suburban and rural New Jersey. Environ Sci Technol. 2008;42:8231–8238. [PMC free article: PMC4120768] [PubMed: 19068799] [CrossRef]
• Werner M, Birner G, Dekant W. Sulfoxidation of mercapturic acids derived from tri- and tetrachloroethene by cytochromes P450 3A: a bioactivation reaction in addition to deacetylation and cysteine conjugate beta-lyase mediated cleavage. Chem Res Toxicol. 1996;9:41–49. [PubMed: 8924615] [CrossRef]
• White GL, Wegman DH (1978). NIOSH Health Hazard Evaluation Report, Lear Siegler Inc., Marblehead, MA. HETA 78-68-546. Cincinnati, OH, USA: United States National Institute for Occupational Safety and Health .
• White IN, Razvi N, Gibbs AH, et al. Neoantigen formation and clastogenic action of HCFC-123 and perchloroethylene in human MCL-5 cells. Toxicol Lett. 2001;124:129–138. [PubMed: 11684365] [CrossRef]
• WHO (1984) Tetrachloroethylene. Environmental Health Criteria 31. Geneva, Switzerland: World Health Organization, International Programme on Chemical Safety .
• Wu CF, Liu LJ, Cullen A, et al. Spatial-temporal and cancer risk assessment of selected hazardous air pollutants in Seattle. Environ Int. 2011;37:11–17. [PubMed: 20619894] [CrossRef]
• Yoshioka T, Krauser JA, Guengerich FP. Tetrachloroethylene oxide: hydrolytic products and reactions with phosphate and lysine. Chem Res Toxicol. 2002;15:1096–1105. [PubMed: 12184794] [CrossRef]
• Zhou YC, Waxman DJ. Activation of peroxisome proliferator-activated receptors by chlorinated hydrocarbons and endogenous steroids. Environ Health Perspect. 1998;106 Suppl 4:983–988. [PMC free article: PMC1533341] [PubMed: 9703482]
• Zhu J, Newhook R, Marro L, Chan CC. Selected volatile organic compounds in residential air in the city of Ottawa, Canada. Environ Sci Technol. 2005;39:3964–3971. [PubMed: 15984771] [CrossRef]
• Ziegler DM. Recent studies on the structure and function of multisubstrate flavin-containing monooxygenases. Annu Rev Pharmacol Toxicol. 1993;33:179–199. [PubMed: 8494339] [CrossRef]
• Ziegler DM. An overview of the mechanism, substrate specificities, and structure of FMOs. Drug Metab Rev. 2002;34:503–511. [PubMed: 12214662] [CrossRef]
• Zoccolillo L, Amendola L, Insogna S. Comparison of atmosphere/aquatic environment concentration ratio of volatile chlorinated hydrocarbons between temperate regions and Antarctica. Chemosphere. 2009;76:1525–1532. [PubMed: 19541344] [CrossRef]