Assessment of the potential mutagenicity of organochlorine pesticides (OCPs) in contaminated sediments from Taihu Lake, China.

The residual levels and mutagenic potency of OCPs were studied in surface sediments collected from Taihu Lake, China. The concentrations of OCPs detected in surface sediments revealed a wide range of fluctuation from 4.22 to 461ng/g dry weight (dw). Among the individual components of OCPs, much higher coefficients of variance (0.38-1.57) for each compound were detected, indicating significant difference of OCP residues among different areas over the lake. Mutagenicity of the crude extractable organic matter (EOM) from surface sediments in six typical regions was performed with Salmonella/microsome tests (Salmonella strains TA98 and TA100 with/without metabolic activation S9 mix). TA98 was more sensitive and the main mutagens detected were frameshift toxicants. Sediments collected from the north-west showed higher potency to induce mutagenicity than other regions. Poor correlation between OCP concentrations and mutagenicity suggested OCPs were not responsible for the detected mutagenic effects in sediments. Combining chemical analysis with bioassays will be a novel and useful tool for finding out the responsible environmental mutagens.