Low-Cost Adsorbents for Reducing Pesticides Impact On Environmental Quality.

The use of pesticides in plant protection releases large quantities of pesticides into rivers and streams through runoff water and sediment and into groundwater through seepage. Nine biobeds (ground cavity filled with a mixture of composted organic matter, topsoil, and a surface grass) were established at Kentucky State University research farm (Franklin County, KY) to study the impact of this practice on reducing surface runoff water contamination by residues of dimethazone and trifluralin herbicides arising from an agricultural field. Biobed (biofilter) systems were installed at the bottom of the slope of specially designed runoff plots to examine herbicides retention and degradation before entering streams and rivers. In addition to biobed systems, three soil management practices: municipal sewage sludge (SS), SS mixed with yard waste compost (SS+YW), and no-mulch (NM) rototilled bare soil were used to monitor the impact of soil amendments on herbicide residues in soil following natural rainfall events. Biobeds installed in NM soil reduced dimethazone and trifluralin by 84 and 82%, respectively in runoff water that would have been transported down the land slope of agricultural fields  contaminating natural water resources. Biobeds installed in SS and SS+YW treatments reduced dimethazone by 65 and 46% and trifluralin by 52 and 79%, respectively. Biobed systems could be used to intercept pesticide-contaminated runoff from agricultural fields, creating optimum conditions for sorption and biodegradation such that the amount of pesticides adjacent to water bodies is significantly reduced. This may provide a potential solution to pesticide contamination of surface water from farmlands.