|Smith Jr, Sammie|
|Shields Jr, Fletcher|
Submitted to: American Chemical Society Symposium Series
Publication Type: Book / Chapter
Publication Acceptance Date: 7/10/2003
Publication Date: 3/1/2004
Citation: Moore, M.T., Cooper, C.M., Bennett, E.R., Smith Jr, S., Shields Jr, F.D., Farris, J.L. 2004. Vegetated drainage ditch research in the Mississippi Delta Management Systems Evaluation Area (MDMSEA). In: Nett, M.T., Locke, M.A., Pennington, D.A., Editors. American Chemical Society Symposium Series 877. Water Quality Assessments in the Mississippi Delta: Regional Solutions. National Scope. p. 194-203.
Interpretive Summary: Best management practices (BMPs) are used by farmers to reduce the amount of pesticides, sediments, and nutrients that run off farm fields and enter rivers, lakes, and streams. Many BMPs require the farmer to sacrifice acreage or involve significant financial costs. One low-cost alternative is to use agricultural drainage ditches as a new BMP for reducing effects of agricultural runoff. The current research describes how plants left in typical agricultural drainage ditches can act as binding sites for pesticides that have run off fields during storm events. When these pesticides bind to plant material they can no longer harm fish and beneficial insects which may be in the water. The ditches serve as a filter for agricultural runoff.
Technical Abstract: Since 1998, two vegetated agricultural drainage ditches within the Mississippi Delta Management Systems Evaluation Area (MDMSEA) have been used to determine whether ditches can effectively mitigate concentrations of pesticides associated with runoff. Through simulated storm events, pesticides and water were amended into drainage ditches at concentrations indicative of a typical runoff event. Study results allude to the value of ditch vegetation in transferring pesticides out of the aqueous phase, thereby mitigating potential risks to aquatic receiving systems. Between 95-97% of the aqueous pyrethroid insecticides were successfully transferred from the aqueous phase to plant material just three hours following the simulated storm events. Pesticide toxicity evaluations have provided data indicating remediation of contaminated ditch water and sediment following simulated storm events. Analysis of fate data indicated that ditches can effectively mitigate pesticides within reasonable ditch lengths (50-400m), depending upon contributing drainage area and assumed rainfall and runoff percentages.