Partitioning and Transport of Organochlorine Pollutants in the Arctic: From Snowfall to Snowmelt

Volatile and semi-volatile organochlorine (OCs) compounds such as dieldrin, endosulfan and PCBs have frequently been identified as pollutants in remote polar regions, far from their anthropogenic sources. Bioaccumulation of these compounds has been previously documented and poses a potential threat to the health of individuals in Arctic subsistence communities as well as to the broader polar ecosystem. These compounds are carried to the polar regions via atmospheric transport mechanisms, but it is less clear how they partition between air, snow/ice, water and soil. Previous studies have found quantifiable concentrations of OCs in each of these compartments, but the extent to which they interact is still largely unknown. Measurements of the concentration of several organochlorine pesticides and PCB congeners in the air, ice, snowpack, and water were made near Barrow, AK, from February-April 2009 as a project within the OASIS campaign, and again during the seasonal snowmelt in May-June 2009 in conjunction with SNOWNET. Our first dataset, when combined with atmospheric measurements and physical snowpack characterization made by other participants in OASIS, allows us to better understand the seasonal accumulation of OCs on snow and ice. Our second dataset, in which we track the movement of OCs through the snowpack and into meltwater runoff, is used in conjunction with snow deposition and hydrological data collected for the SNOWNET study to present a detailed picture of the release and ultimate fate of OCs incorporated into the snowpack during winter.