Abstract: With the organic chlorine pesticides (666, DDT) as sole carbon resources, three strains, No.153 (Bacillus), No.411 (Achromobacter) and No.512 (Pseudomonas), which can degrade 666 (BHC), were isolated and selected in Tonomura culture medium. The degradation rates of these strains were 59.6%, 56.9% and 56.0% for total amount of 666, and 55.9%, 57.6% and 56.9% for β-666, respectively. The other strains, No.288 (Alcaligenes), No.410 and No.411 (Achromobacter) to degrade DDT were also obtained. The degradation rates of the strains were 59.0%, 47.5% and 45.1% for total amount of DDT, and 59.9%, 57.6% and 49.6% for PP'-DDT, respectively. The degradation effects of the mixtures of the isolated strains in pot and field experiments were similar to those of the pure culture, indicating it is a feasible measure to apply the mixture of strains to degrade residual pesticides in fields.

Key words: Organic chlorine pesticides, Microbial degradation, phosphorus, organic carbon, pollution evaluation, nitrogen, Haihe River Basin., sediment