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Environ Pollut. 2018 Mar;234:297-306. doi: 10.1016/j.envpol.2017.11.033. Epub 2017 Nov 26.

Suspect screening and non-targeted analysis of drinking water using point-of-use filters.

Author information

1
United States Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27709, United States. Electronic address: newton.seth@epa.gov.
2
United States Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27709, United States; Oak Ridge Institute for Science and Education Research Participant, 109 T.W. Alexander Drive, Research Triangle Park, NC 27709, United States.
3
United States Environmental Protection Agency, National Exposure Research Laboratory, Research Triangle Park, NC 27709, United States.
4
Oak Ridge Institute for Science and Education Research Participant, 109 T.W. Alexander Drive, Research Triangle Park, NC 27709, United States; United States Environmental Protection Agency, National Center for Computational Toxicology, Research Triangle Park, NC 27709, United States.
5
United States Environmental Protection Agency, National Center for Computational Toxicology, Research Triangle Park, NC 27709, United States.

Abstract

Monitored contaminants in drinking water represent a small portion of the total compounds present, many of which may be relevant to human health. To understand the totality of human exposure to compounds in drinking water, broader monitoring methods are imperative. In an effort to more fully characterize the drinking water exposome, point-of-use water filtration devices (Brita® filters) were employed to collect time-integrated drinking water samples in a pilot study of nine North Carolina homes. A suspect screening analysis was performed by matching high resolution mass spectra of unknown features to molecular formulas from EPA's DSSTox database. Candidate compounds with those formulas were retrieved from the EPA's CompTox Chemistry Dashboard, a recently developed data hub for approximately 720,000 compounds. To prioritize compounds into those most relevant for human health, toxicity data from the US federal collaborative Tox21 program and the EPA ToxCast program, as well as exposure estimates from EPA's ExpoCast program, were used in conjunction with sample detection frequency and abundance to calculate a "ToxPi" score for each candidate compound. From ∼15,000 molecular features in the raw data, 91 candidate compounds were ultimately grouped into the highest priority class for follow up study. Fifteen of these compounds were confirmed using analytical standards including the highest priority compound, 1,2-Benzisothiazolin-3-one, which appeared in 7 out of 9 samples. The majority of the other high priority compounds are not targets of routine monitoring, highlighting major gaps in our understanding of drinking water exposures. General product-use categories from EPA's CPCat database revealed that several of the high priority chemicals are used in industrial processes, indicating the drinking water in central North Carolina may be impacted by local industries.

KEYWORDS:

Drinking water; Exposome; High resolution mass spectrometry; Non-target analysis; Suspect screening

PMID:
29182974
PMCID:
PMC6145080
DOI:
10.1016/j.envpol.2017.11.033
[Indexed for MEDLINE]
Free PMC Article

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