Assessment of environmental pollution of Taihu Lake by combining active biomonitoring and integrated biomarker response.

Goldfish (Carassius auratus) bred in clean water were transferred into different stations in Taihu Lake for active biomonitoring exposures. The biotransformation enzymes 7-ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST), the antioxidant defense enzymes catalase (CAT), reduced glutathione content (GSH), and lipoperoxidation (TBARS) and metallothionein (MT) in liver were determined as biomarkers during the field exposure period. At the same time, the contents of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and heavy metals in the surface sediments of biomonitoring sites were measured. The total concentrations of PAHs ranged 378.6-1047.8 μg kg(-1) dry weight, PCBs ranged 0.76-3.27 μg kg(-1), OCPs ranged 1.12-3.08 μg kg(-1), and heavy metal Zn ranged 31.82-85.04 mg kg(-1), Cu ranged 13.04-91.02 mg kg(-1), Ni ranged 4.96-28.66 mg kg(-1), and Pb ranged 9.33-22.44 mg kg(-1). The results indicate that persistent organic pollutants exist mainly in Meiliang Bay, while heavy metals are present mainly in Gong Bay. The integrated biomarker response (IBR) was calculated by combining multiple biomarkers to a single value and used to evaluate the toxically induced stress level of populations in different areas. The results demonstrate that Tuoshan and Mashan in Meiliang Bay as well as Dagongshan in Gong Bay showed higher IBR values compared to the other sites. IBR values were in good agreement with OCP concentrations.