Cu^(2+)对缢蛏稚贝的急性毒性及对抗氧化酶活力和丙二醛含量的影响

Acute toxicity of Cu^(2+) and its effects on antioxidant enzymes in Si-nonovacula constricta juveniles

研究了Cu2+对缢蛏稚贝的急性毒性并进行安全评价;根据96 h LC50值设定10、30、40μg/L 3个Cu2+质量浓度梯度进行暴露实验,以缢蛏(Sinonovacula constricta Lamark)稚贝软体组织中过氧化氢酶(CAT)、超氧化物歧化酶(SOD)活性和脂质过氧化物丙二醛(MDA)含量为指标,研究Cu2+污染对缢蛏稚贝的毒性作用。结果表明,Cu2+对缢蛏稚贝96 hLC50为309.742μg/L;不同浓度Cu2+胁迫下,96 h内缢蛏稚贝抗氧化酶(CAT、SOD)活力发生显著的变化(P<0.05),除最高组40μg/L在48 h时CAT活力被显著抑制(P<0.05)外,96 h内绝大部分时间点与沙滤海水对照组相比,各暴露组抗氧化酶(CAT、SOD)活性处于诱导状态;96 h内各暴露组缢蛏稚贝丙二醛(MDA)含量均明显高于对照组(P<0.05)。研究认为,CAT、SOD活性及MDA含量变化可反映缢蛏稚贝受Cu2+伤害的程度,可用作缢蛏安全性风险评价的参考依据。

We evaluated the acute toxicity of Cu2＋ and its effects on antioxidant enzymes in Sinonovacula con-stricta juveniles.The results of acute toxicity test showed that the median 96 h lethal concentration（LC50） for Cu2＋ was 309.74 μg/L.We also measured catalase（CAT） and superoxide dismutase（SOD） activity and malondialde-hyde（MDA） content in the soft tissue of clams exposed to 10,30,or 40 μg/L Cu2＋,respectively,at 6,12,24,48,72 and 96 h of exposure.CAT activity of the maximum exposed group was lower after 48 h relative to the controls whereas both CAT and SOD activity of all exposure groups were higher at 6,24,72 and 96 h.The MDA content was higher in fish exposed to Cu2＋ than in the control group after 96 h.Our results suggest that exposure to Cu2＋ causes oxidative damage in S.constricta juveniles.