Assessment of Problems Associated with Landfilling or Land Application ofPesticide Waste and Feasibility of Cleanup by Microbiological Degradation

摘要

To improve the prospects for use of land application as a remediation tool andthe possibility of augmenting biodegradation of pesticide wastes in soil, a series of laboratory experiments were designed to explore microbiological aspects of the persistence of high concentrations of herbicides in soil. Most of the studies focused on the alachlor, which is an acetanilide herbicide used in corn and soybeans. In laboratory experiments, alachlor was not degraded after simulated spills of 1000 ppm or 10,000 ppm. In contrast, 10 ppm and 100 ppm doses of alachlor were partially degraded into water-soluble metabolites. Technical-grade alachlor and an emulsifiable concentrate formulation were metabolized similarly. Microbial populations and dehydrogenase activity in soil were reduced upon exposure to 1000 ppm or 10,000 ppm alachlor, and lack of degradation of these high concentrations was attributed to microbial toxicity from alachlor itself rather than additives in its formulation.