PARENT SESSION

PM01 Amphibian Research and Monitoring
Exhibit Hall
8:00 AM - Monday, 10 November 2003

(PM002) Pesticide and POPs in sediment from amphibian habitats in the Sierra Nevada Mountain Range, USA.

Drakeford, L.¹, McConnell, L.¹, Fellers, G.², Sparling, D.³, Cowman, D.³, Kleeman, P.², ¹ U.S. Department of Agriculture, Agricultural Research Service, Beltsville, MD, USA² U.S. Geological Survey, Point Reyes, CA, USA³ U.S. Geological Survey, Laurel, MD, USA

ABSTRACT- The Sierra Nevada Mountains (SNM) are an important alpine habitat for numerous amphibian species. In recent years, exposure to atmospherically transported pesticides has been postulated as a possible factor in SNM amphibian population declines. Earlier studies have indicated that the Pacific Chorus frogs (Pseudacris Regilla) are exposed to organophosphate insecticides, endosulfan, DDE and HCHs. As part of a larger study to determine the impact of atmospherically transported residues to the SNM, sediment samples were collected in 2001 and 2002 from 61 stations from amphibian habitats (ponds, meadows and wetlands) in four east-west transects from control sites on the California coast to Lassen, Yosemite, Sequoia National Parks, and Lake Tahoe. Approximately 15 g of wet sediment was extracted using accelerated solvent extraction followed by clean-up on an alumina column and analysis using gas chromatography-mass spectrometry in negative chemical ionization mode. Samples were analyzed for a number of currently-used insecticides and fungicides, as well as other banned organochlorine pesticides, 20 polychlorinated biphenyl congeners, five polybrominated diphenyl ethers (PBDEs), and toxaphene. Preliminary results show endosulfan sulfate (median conc. 1.1 ng/g dry wt, max conc. 5.3 ng/g dry wt.) and -chlordane (median conc. 0.3 ng/g dry wt, max conc. 1.5 ng/g dry wt.) as the most frequently detected chemicals with - and -endosulfan, other chlordane isomers, and PBDEs occasionally observed.

Key words: Amphibians, Pesticide, Sediment, Atmospheric