| dc.description.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 cischlordanes
(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 | en_US |
