Biochemical responses of freshwater fish Carassius auratus to polycyclic aromatic hydrocarbons and pesticides

The freshwater fish Carassius auratus was chosen as an experimental subject, and their hepatic biochemical responses to the medium-term exposure of Benzo(k)fluoranthene (BkF) alone and in combination with PCB118 and dichlorodiphenyltrichloroethane (DDT) were investigated by measuring the reduced glutathione (GSH), glutathione S-transferase (GST), and thiobarbituric acid reactive substances (TBARS), to assess sublethal effects. The hepatic GSH content was significantly inhibited by organic pollutants, alone and in mixtures, while the TBARS content was significantly induced after three days of exposure. Bell-shaped concentration-response charts of GST activities were obtained. Significant dose-response relationships were found for hepatic GSH and TBARS contents of all concentrations and for the GST activity, except at the highest concentration. The GSH content, GST activity, and TBARS content in Carassius auratus were confirmed as useful biomarkers of exposure to organic pollutions.