On-Farm Remediation of Pesticide Wastes using Biobeds
Project Code: MUR07-050
Thomas Wolf - Agriculture and Agri-Food Canada
To evaluate the use of biobeds to reduce environmental contamination with pesticides and discuss the degradation potential of high-impact pesticides in used Canada
Pesticide waste disposal is a concern for Canadian agricultural producers. Improper disposal of leftover pesticide mixtures from sprayer operation or cleaning, as well as spills during loading can contaminate wetlands, ponds, waterways, or drinking water wells. Traditional engineering solutions (concrete pads with containment) are costly and have not been adopted. Most pesticide labels provide inadequate direction for waste disposal.
Biodegradation by bacteria, actinomycetes, fungi and specific protozoa is considered the primary mechanism for transforming pesticides in soils. In its simplest form a biobed consists of a clay-lined hole filled with a mixture of top-soil, peat or compost and straw. The top-soil serves as the source for the microorganisms in the system. The peat or compost is included for its high water-holding capacity and provides a large organic matter surface area for adsorption, whereas the straw serves as a carbon source for lignin-degrading microorganisms.
Biobeds provide excellent conditions for stopping the movement of pesticides into water sources, by adsorbing the pesticide to the surfaces of the compost or peat, but still leaving the pesticides available for degradation. The inclusion of straw is thought to select those microorganisms that specialize in the degradation of recalcitrant materials like lignin and pesticides. When implemented at lab- or farm scale, biobeds have been shown to reduce pesticide concentration in leachate to a much greater extent than soil beds alone.
As a result of the biobed technology's potential, the overall objective of this project is to evaluate the biobed concept for on-farm use in Canada. In the first year, laboratory-scale biobed reactor vessels will be constructed using bioremediation media. Pesticide residues will be discharged into the biobed, and effluent from the biobed will be collected and analyzed. Degradation rates will be compared to those in soil alone. Depending on results and availability of funding, in the second year, a biobed will be established on a farm site and its performance assessed.
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