Chernyak, S. M. USGS-BRD, Great Lakes Science Center, Sergei_Chernyak@nbs.gov
McConnell, L. M. USDA-Beltsville Agricultural Research Center, mcconnel@asrr.arsusda.gov
Rice, C. P. USDA-Beltsville Agricultural Research Center, crice@asrr.arsusda.gov

 
MODELING THE BEHAVIOR OF CHLORPYRIFOS AND TRIFLURALIN IN THE CHUKCHI SEA.
 
Based on measured values for the pesticides, chlorpyrifos and trifluralin, that were obtained in the 1993 BERPAC expedition to the Bering/Chukchi Seas the loading of these chemicals into this pristine ecosystem is modeled. Different HLC values, adjusted according to temperature and salinity, were used in a fugacity-based model to describe the flux of chlorpyrifos and trifluralin into the Chukchi sea which is the northernmost of these two seas. Gas exchange flux and wet (esp. for chlorpyrifos) deposition accounted for most of the loading with very little predicted from particle deposition. Selected adjustment of both salinity and temperature to the specific values occurring over the summer at this location were shown to be important variables especially affecting final gas exchange loadings. Modifying standard constants for increased salinity lowered the loadings of both trifluralin and chlorpyrifos, while temperature adjustments down to lower temperatures increased these loadings. Adjustments to specific water differences also tended to increase the loadings. The predicted fluxes of chlorpyrifos ranged from 112-117 ug/km2 day (gas), and 33 ug/km2 day (rain); the gas flux for trifluralin was 104-109 ug/km2 day and there was essentially no rain flux.
 
Day: Wednesday, Feb. 3
Time: Poster
Location: Sweeney Center
 
Code: SS50WE0057S