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[Toxic effects of petroleum hydrocarbons and copper on polychaete Nereis diversicolor and on its antioxidant enzyme systems].

Under the condition of the laboratory simulation, the toxic effects of petroleum hydrocarbons and various concentrations of copper (Cu2+) on the polychaete Nereis diversicolor and on its antioxidant enzyme defense systems were examined. The results indicate that both petroleum hydrocarbons and CU2+ have high toxicity to the polychaete. After a 3-day exposure to petroleum hydrocarbons and Cu2+, the value of LD50 was 117.5 microL x L(-1) and 864.0 microg x L(-1), respectively. The activities of peroxidase (POD) and superoxide dismutase (SOD) were influenced significantly through a 5-day exposure to single pollution of Cu2+. The activity of POD was inhibited at first and then enhanced gradually; on the contrary, the activity of SOD showed a tendency of induction firstly and then inhibition. After exposed to petroleum hydrocarbons at the concentration of the value of LD50 for 5 days, POD activity of the polychaete was not significantly induced, and the activity of SOD was lower than that of control. A 5-day exposure to the joint-pollution of petroleum hydrocarbons and Cu2+ could bring out a decrease in the activities of POD and SOD firstly and then an increase. The changes in the activity of SOD can better reflect the toxic effects of pollutants on the polychaete.