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Environ Sci Technol. 2015 Dec 1;49(23):13844-52. doi: 10.1021/acs.est.5b01303. Epub 2015 Aug 18.

20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean.

Author information

1
Air Quality Processes Research Section, Environment Canada , 6842 Eighth Line, Egbert Ontario, L0L 1N0 Canada.
2
Analytical Chemistry and Environmental Sciences (ACES), Stockholm University , SE-106 91 Stockholm, Sweden.
3
Department of Thematic Studies - Environmental Change, Linköping University , SE-581 83 Linköping, Sweden.
4
Research Unit: Environmental Sciences and Development, North-West University , Private Bag X6001, Potchefstroom, 2520 South Africa.
5
Environmental Monitoring and Reporting Branch, Ontario Ministry of the Environment , 125 Resources Road, West Wing, Toronto, Ontario, M9P 3V6 Canada.
6
Centre for Earth Observation Science, University of Manitoba , 474 Wallace Building, 125 Dysard Road, Winnipeg, R3T 2N2 Canada.
7
Department of Chemistry, Umeå University , SE-901 87 Umeå, Sweden.

Abstract

The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DIEL), chlorobornanes (ΣCHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water-air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for ΣCHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air-surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

PMID:
26196214
DOI:
10.1021/acs.est.5b01303
[Indexed for MEDLINE]
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