Organic pollutants and ambient severity for the drinking water source of western Taihu Lake

Measurement of the organic compounds found in western Taihu Lake and evaluation of the ambient severity (AS) of the water using multimedia environmental goals (MEG) was conducted. The comet assay and the antioxidant enzyme approach were used to test the potential toxicity of water samples on the microalgae Euglena gracilis. Total concentrations of 25 organic pollutants in samples from two sites were 6.700 and 14.655 mu g/l, respectively, with a calculated total ambient severity (TAS) of less than 1 and therefore minimal risk to human and ecological health. Organic extracts from the samples at these two sites was found to induce dose-dependent DNA damage on microalgae cells. DNA damage together with changes in superoxide dismutase (SOD) and peroxidase (POD) activities indicated that the potential pollutant toxicity was far higher at one of the two sites than at the other site. The comet assay combined with the activities of antioxidant enzymes may be of value as a biomarker for presence of organic pollutants in drinking water sources.