The 2011 ASHS Annual Conference

Pesticides and other anthropogenic pollutants once introduced into the environment are subjected to biological and nonbiological transformation processes. Microorganisms play a vital role in maintaining the environmental quality through their metabolic activities. The highly versatile metabolic capabilities of fungi and bacteria can be used to reclaim polluted ecosystems. A variety of biological, chemical, and physical methods have been used for degradation and detoxification of pesticides. However, conventional clean- up methods are costly and not always effective. Agrochemical storage and handling practices have been targeted as a potential point source contamination of soil and groundwater. Use of “biobed” to contain and biodegrade pesticides may be a cost-effective alternative. A biobed is an in-ground treatment unit designed to contain spills of pesticides and degrade the chemicals through microbial activity. Microbial activity may be enhanced by altering conditions conducive to degradation. In this study, the technical potential of using biobed was evaluated in a series of ex-situ experiments using small scale biobeds with mixtures of “top soil, peat, and straw” as substrate. Herbicides used included glyphosate, atrazine, acetochlor, and metolachlor, the most widely used herbicides for crops. The herbicide-degrading potential of the biobed substrate mixtures was determined by analyzing sub-samples to measure residual herbicide concentrations. The greatest concentration of herbicide residue  was found when organic matter was included in the biobed media, especially when 50% of the media volume comprised of peat. The results of enzyme activity indicated that addition of straw as carbon source in the biobed media enhanced acid and alkaline phosphatases activities and the activity was correlated with the amount of straw added.