The influence of cadmium on the antioxidant enzyme activities in polychaete Perinereis aibuhitensis Grube (Annelida: Polychaeta)

The infaunal polychaete Perinereis aibuhitensis Grube, distributed widely along Asian coasts and estuaries, is considered a useful animal model in ecotoxicological tests and a promising candidate in biomonitoring programs. This paper deals with the activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidases (GSH-Px) in infaunal polychaete P. aibuhitensis exposed to a series of sublethal water-bound cadmium (Cd) concentrations (0, 0.34, 1.72, 3.44, 6.89, and 17.22 mg L-1) under a short-term exposure (1-8 d). The results indicate that the SOD and GSH-Px activities in P. aibuhitensis are stimulated first and then renewed to the original level. The CAT activity of worms decreases at an earlier exposure time but increases to the control values at a later exposure time. Our study suggests that Cd can interfere with the antioxidant defense system of P. aibuhitensis. However, the changes in antioxidant enzyme activities for this species do not show the best promise as biomarkers in Cd biomonitoring of estuarine and coastal zones because weak or non-dose-effect relationships between the antioxidant enzymes activities and Cd levels are found.