Abstract:Research on the influence of heavy metals and other environmental pollutants on the antioxidant defense system has become one of the hotspots of ecological toxicology in recent years. Effects of three heavy metal ions, Hg(Ⅱ), Pb(Ⅱ), and Cd(Ⅱ) on the activity of total superoxide dismutase (T-SOD) in the tissue of Calanus sinicus were examined through outside body sublethal toxicity testing. The results showed that the T-SOD activity changed markedly under prolonged exposure to these ions. The activity of T-SOD reached the maximum at 12 hours, when Hg(Ⅱ) concentrations were 0.001 3~0.005 3 mg/L. When the concentrations of Pb(Ⅱ) were 0.468 0, 0.936 0, and 1.872 0 mg/L, the activity of T-SOD reached the maximum at 36 h, 24 h, and 12 h, respectively. Effects of Hg(Ⅱ) and Pb(Ⅱ) on the SOD activity increased first and then decreased during the prolonged exposure. The activities of SOD underwent a course of increase-decrease-increase-decrease in the presence of Cd(Ⅱ). At all the three concentrations of Cd(Ⅱ), the activity of T-SOD reached the maximum at 12 hours.
