PM08 Sediment Quality Assessment
Exhibit Hall
8:00 AM - Monday
(PM119) Pesticides in California Wetlands: Integrating Exposure and Effects.
Kuivila, K1, Datta, S2, 1 US Geological Survey, Sacramento, CA, USA2 University of California, Davis, Davis, CA, USA
ABSTRACT- Wetland ecosystem health is affected by a variety of stressors including toxic contaminants. The goal of this interdisciplinary project is to develop indicators of wetland health by evaluating the response of wetland biota to specific stressors such as pesticides. Surface sediment samples from five coastal California wetlands were analyzed for 41 current-use pesticides by microwave-assisted solvent extraction and gas chromatography/mass spectrometry. Pesticides were detected at Carpinteria Marsh near Santa Barbara and Stege Marsh near Richmond, but not at the marshes in San Francisco Bay (China Camp) and Tomales Bay (Tom's Point and Walker Creek). Two pyrethroid insecticides (bifenthrin and permethrin) and one organophosphate insecticide (chlorpyrifos) were detected at Carpinteria Marsh, with maximum concentrations of 24, 51, and 31 ng/g dry weight, respectively. The highest concentrations were detected at the edge of the marsh that receives input from areas where these insecticides are applied to nurseries, greenhouses, and row crops. Laboratory studies and bioassays will be used to estimate the bioavailability and effects of these insecticides on aquatic organisms. In contrast to Carpinteria Marsh, two thiocarbamate herbicides (eptam and molinate) were detected at Stege Marsh. The highest concentrations were detected at the most inland site, with eptam at 205 ng/g and molinate at 61 ng/g, dry weight. These herbicides are not used in the surrounding watershed; therefore, the nearby former agrochemical plant that manufactured these chemicals is the likely source of contamination. Future studies will estimate the potential effect of these herbicides on wetland plants. The results of this integrated field and laboratory study will improve our understanding of pesticide exposure and effects in wetlands and provide valuable information to CALFED and other resource managers for planning wetland restoration projects.
Key words: pyrethroids, pesticides, herbicides, wetlands