Joint stress of copper and petroleum hydrocarbons on the polychaete Perinereis aibuhitensis at biochemical levels.

Responses of the polychaete Perinereis aibuhitensis Grube to single and joint stress of copper (Cu) and petroleum hydrocarbons (PHCs) at biochemical levels (including superoxide dismutases, SOD; peroxidases, POD; and the content of total soluble protein, TSP) were investigated under controlled laboratorial conditions. Significant decreases in SOD activity in the first 3 days of single exposure to Cu or PHCs were observed. Although SOD activity increased and returned to the level of the control on day 6 after having decreased on day 3 under single stress of Cu or PHCs, Cu and PHCs had complicated interactive influences on SOD activity in P. aibuhitensis. Their joint effects on SOD activity depended on concentration combinations and exposure time, called double-dose dependent effects. The POD activity and the content of TSP remained generally constant under both single and joint stress of Cu and/or PHCs, compared with the control. The beef-witted responses of investigated biochemical parameters in this study might suggest that toxic effects of pollutants with emphasis on the action of abiotic parameters and the time factor on the antioxidant enzymes in the polychaete should be addressed in the future work.