Submitted to: SETAC Conference
Publication Type: Abstract Only
Publication Acceptance Date: 7/15/2007
Publication Date: 11/12/2007
Citation: Moore, M.T., Cooper, C.M., Kröger, R., Smith Jr, S., Locke, M.A., Cullum, R.F. 2007. Use of Harvested Rice (Oryza Sativa) Fields for Diazinon Runoff Mitigation. Abstracts of the 2007 Annual Meeting of the Society of Environmental Toxicology and Chemistry. p. 53. Interpretive Summary: Abstract only. Interpretive summary not required.
Technical Abstract: In landscapes defined by intensive agriculture, management practices are often needed to abate effects of potential non-point source pollution. Innovative research focuses on using rice (Oryza sativa), a wetland cereal crop, for pesticide mitigation both pre- and post-harvest. Because rice fields are delineated by water-retaining levees, water control can be manipulated to alter hydraulic residence time as needed for effective mitigation. Portions of two ponds at the University of Mississippi Field Station were drained, tilled, and planted with rice in May 2006. A third (unvegetated) pond was also drained and used as a control. A simulated storm event was conducted, introducing diazinon as runoff into the rice fields in November 2006. Amount of diazinon used was based on recommended field application rates and observed concentrations in previously collected runoff studies. Water, sediment, and plant samples were collected both spatially and temporally for 72 hours post-application. There was no statistically significant difference in the outflow diazinon mass between the two planted ponds. Although the control pond exhibited greater outflow diazinon mass than both the planted ponds, it was only statistically greater (slightly) than pond 1. Based on comparisons of inflow versus outflow concentrations, both rice ponds (1 and 2) mitigated 26-72% of diazinon concentrations. According to the mass balance, only a small fraction overall of the diazinon concentrations were associated with the rice (plant material). Current studies are evaluating pre-harvest pesticide processing capacities of rice ponds, as well as the impact of manipulation of hydraulic residence time on diazinon and other pesticide mitigation. Information generated from these studies will provide farmers and other natural resource conservation entities valuable options for efficient use of various management practices.