Atmospheric concentrations and deposition of organochlorine pesticides in the US Mid-Atlantic region

Abstract

Organochlorine pesticides (OCPs) were measured in the atmosphere over the period January 2000–May 2001 at six locations as part of New Jersey Atmospheric Deposition Network (NJADN). Gas phase, particle phase and precipitation concentrations of 22 OCP species, including chlordanes, DDTs, HCHs, endosulfan I and II, aldrin and diedrin, were measured. OCPs are found predominantly in the gas phase in all seasons, representing over 95% of the total air concentrations. Most of the pesticides measured display highest concentrations at urban sites (Camden and New Brunswick), although in many cases the differences in geometric mean concentrations are not statistically significant. The relationship of gas-phase partial pressure with temperature was examined using the Clausius–Clapeyron equation; significant temperature dependencies were found for all OCPs, except aldrin. Atmospheric depositional fluxes (gas absorption into water+dry particle deposition+wet deposition) to the New York–New Jersey Harbor Estuary of selected OCPs were estimated at NJADN sites. Atmospheric concentrations of dieldrin, aldrin and the HCHs are similar to those measured by the Integrated Atmospheric Deposition Network (IADN) in the Great Lake Region. In contrast, concentrations of DDTs, chlordanes and heptachlor are higher in the Mid-Atlantic compared to the Great Lakes, suggesting that the New York–New Jersey Harbor Estuary receives higher fluxes of these chemicals than the Great Lakes.