Submitted to: SETAC Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 1, 2004
Publication Date: November 14, 2004
Citation: Goel, A., McConnell, L.L., Torrents, A. 2004. Pesticides in the atmosphere of the delmarva peninsula. Fourth SETAC World Congress. Nov. 14-18, 2004, Portland, OR. Abstract No.PT066, p.299.
Aerial deposition is likely to be an important source of pesticides to surface waters and wetland areas in the Chesapeake Bay Watershed, especially the Delmarva Peninsula, an intensely agricultural area stretching along the Eastern shore of the Chesapeake Bay. Three different sites on the Peninsula were chosen for the assessment of atmospheric pesticide concentration in the region. During the agricultural season (April to September) of 2000-2003, weekly air (n=200) and event based rain (n=399) samples were collected. Target pesticides included organochlorines, organophosphates and triazines, and others used in corn, soybean and vegetable production. The detection of herbicides coincided with the timing of application (April to July) whereas the fungicide chlorothalonil and most of the insecticides were seen throughout the sampling period although the concentrations were highest during June-September. Concentrations in air and precipitation are dependent upon the timing of application, pesticide chemistry, ambient temperature as well as the timing of rainfall. Across the Peninsula, chlorothalonil was the most frequently detected compound (87-96%) in precipitation followed by metolachlor (50-66%) and atrazine (45.3-58.3%). Chlorpyrifos, alpha-endosulfan and trifluralin were also detected frequently. The net pesticide wet fluxes were in the range of 0.9-1.6 ug/m2-L rainfall, with the highest flux occurring at a wildlife reserve site located very close to production fields. Chlorothalonil was the single biggest contributor to the wet flux (28-53%) and closely follows the patterns in rainfall.