Microbial degradation of chlorothalonil in agricultural soil: A laboratory investigation

The employment of pesticides for crop protection must be balanced by a total awareness of the detrimental effects they may have on the environment. Pesticide residues in soil, and metabolites resulting from microbial metabolism of such compounds, may contribute to pollution of streams, affect microbial diversity, and influence essential symbiotic associations between microorganisms and crops. Chlorothalonil, an extensively used fungicide, is classified as a probable human carcinogen by the US EPA. Microbial degradation of chlorothalonil residues in different types of agricultural soil was investigated in the laboratory. Bacterial plate count and GC analysis results indicated that indigenous soil bacteria were able to utilize chlorothalonil, although the rate of chlorothalonil metabolism appeared to be influenced by soil characteristics. (C) 2000 by John Wiley & Sons, Inc.