Tuesday, November 6, 2007
231-16

Effects of Switchgrass Buffer Strip on Endosulfan Runoff and Soil Microorganisms.

Cristina Clark-Cuadrado1, Stewart Reed2, Krishnaswamy Jayachandran3, and Ricardo Joseph2. (1) Environmental Studies, Florida International University, 11200 S.W. 8th Street, Miami, FL 33199, (2) USDA-ARS, 2028 Southeast 23 ave., Homestead, FL 33035, (3) 11200 SW 8th St., Florida International University, Florida International University, Dep. of Environmental Studies, Miami, FL 33199

Endosulfan (6,9-Methano-2,4,3-benzodioxathiepin, 6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a- hexahydro-, 3-oxide) is a persistent organochlorine pesticide that poses danger to humans, animals and beneficial insects. Its degradation product, endosulfan sulfate (6,7,8,9,10,10-Hexachloro-1,5,5a,6,9,9a-hexahydro- 6,9-methano-2,4,3-benzodioxathiepin-3,3-dioxide) is as toxic as, and more persistent than the parent endosulfan. Though it is extensively used, there is limited information on the effectiveness of buffer strips for the reduction of endosulfan transport from agricultural fields. In addition, there is a lack of information on the effects of endosulfan on soil microorganisms. The fate and transport of endosulfan was monitored through a switchgrass buffer strip versus bare soil downhill from a snap bean field to which commercial endosulfan was applied at the recommended rate of 1.12 kg a.i. ha-1. Soil samples were taken from the switchgrass buffer strip and bare soil areas at different depths and distances from the bean field to determine the concentrations of endosulfan and its metabolites. Gas chromatography method is being used to determine endosulfan and its metabolites concentrations. Soil bacteria and fungi were also monitored to determine the effects of endosulfan on soil microorganisms.