:: Journal of International Environmental Application & Science ::

Year 2007, Volume II (Issue III-IV)

Journal of International Environmental Application and Science , Vol. 2, No. 2 (2007), 40-50

Distribution and Spatial Variation in Surface Sediment Pesticides of Mississippi Alluvial Plain

Scott S. Knight 1, Richard E. Lizotte Jr.1, Sammie Smith Jr.1, Charles T. Bryant1

1USDA-ARS National Sedimentation Laboratory, P.O. Box 1157; 598 McElroy Drive, Oxford, MS 38655 USA

Abstract: As part of a broader sediment quality assessment, we examined the effects of varying land-use practices on sediment pesticide contamination in water bodies within the lower Mississippi alluvial plain (LMAP), USA. Three categories of land-use practices were studied: intensive row-crop agriculture (water bodies listed as impaired according to USEPA section 303d Clean Water Act), row-crop treated with best management practices (BMP), and < 1% row crop within White River National Wildlife Refuge (NWR). Seventeen current and historic-use pesticides were measured in surface sediments (top 5 cm) within three 303d, BMP and NWR water bodies (nine total) from June-July 2004. Significant (P < 0.05) spatial variation occurred in 10 of 17 pesticides measured in sediments. Current-use herbicides were greatest in 2 of 3 NWR water body sediments and lowest in 2 of 3 BMP water body sediments. Current-use insecticides were greatest in 2 of 3 NWR water body sediments but lowest in 303d sediments. In contrast, historic-use pesticides (ΣDDT) were greater in 303d sediments and lower in BMP sediments. Columbus Lake (NWR) sediment had consistently lower concentrations for nearly all pesticides. Overall spatial patterns of sediment pesticide contamination in LMAP were due to agricultural land-use practices as well as the degree of static or flow-through conditions of each water body. Results indicate that while NWR water bodies have extensive natural riparian areas that can process contaminants, they still receive significant influx of current-use pesticides, and BMPs treating similar water bodies can mitigate the degree of sediment contamination.  
Keywords: Agriculture, Sediment quality, Insecticide, Herbicide, Best Management Practices.