Cd2+和Pb2+对花翅摇蚊幼虫的毒性及 对三种生物化学标志物的影响

Toxicity of Cd2+ and Pb2+ to Chironomus kiiensis larvae, and its effects on three biochemical markers

王剑南；许力山；曹传旺

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DOI：10.7679/j.issn.2095-1353.2019.116

作者单位：东北林业大学林学院，哈尔滨 150040；东北林业大学林学院，哈尔滨 150040；东北林业大学林学院，哈尔滨 150040

中文关键词：重金属；花翅摇蚊；联合毒性；生物化学标志物

英文关键词：heavy metal; Chironomus kiiensis; acute and joint toxicity; biochemical markers

中文摘要：【目的】 为了探讨花翅摇蚊Chironomus kiiensis Tokunaga对重金属Cd²⁺和Pb²⁺胁迫响应。     【方法】  测定Cd²⁺和Pb²⁺对花翅摇蚊4龄幼虫的急性毒性、联合毒性以及体内3种生物化学标志物（CAT、SOD活性和MT含量）的影响。【结果】 花翅摇蚊幼虫暴露于重金属Cd²⁺和Pb²⁺及混合离子中表现出典型的中毒症状，且24 h和48 h重金属Cd²⁺致死中浓度LC₅₀显著低于Pb²⁺的LC₅₀。混合离子Cd²⁺和Pb²⁺的联合毒性随着不同配比和作用时间呈现差异性；24 h Cd²⁺+Pb²⁺1︰1配比表现为部分相加作用，Cd²⁺+Pb²⁺2︰1和1︰2配比表现为拮抗作用；而作用48 h不同配比联合毒性均为部分相加作用。2种单一和混合重金属Cd²⁺+Pb²⁺均不同程度对摇蚊体内SOD和CAT产生抑制作用，而暴露于Cd²⁺和Pb²⁺及其混合离子作用下MT含量显著高于对照，且随着时间表现为先增加后降低。【结论】 重金属Cd²⁺和Pb²⁺对摇蚊幼虫具有急性和联合毒性，体内抗氧化酶系CAT、SOD及体内MT参与了重金属污染物的胁迫的应答响应，并表现出时间-剂量效应，可作为水体环境质量监测的生化标志物。

英文摘要：[Objectives]  To investigate the effects of heavy metal exposure on Chironomus kiiensis larvae. [Methods]  The toxicity of Cd²⁺, Pb²⁺ and Cd-Pb ions, to 4th instar C. kiiensis larvae, and on three biochemical markers (CAT, SOD and MT) were measured. [Results]  C. kiiensis larvae developed typical toxic symptoms after exposure to Cd²⁺ and Pb²⁺ and their ions. The LC₅₀ of Cd²⁺ was significantly lower than that of Pb²⁺ after 24 h and 48 h. The joint toxicity of Cd²⁺ and Pb²⁺ varied with ion ratios and exposure time. The joint toxicity of 1︰1 Cd²⁺+Pb²⁺ was partially additive whereas 2︰1 and 1︰2 of Cd²⁺+Pb²⁺ had an antagonistic effect after 24 h. However, the joint toxicity of different ratios of Cd²⁺+Pb²⁺ was partially additive after 48 h. SOD and CAT activity was inhibited to various degrees by Cd²⁺ and Pb²⁺. The MT content of larvae exposed to Cd, Pb and mixed ions of these elements, was significantly higher than that of the control, and MT content increased, then decreased, with duration of exposure. [Conclusion]  Cd²⁺ and Pb²⁺ are both independently, and jointly, toxic to C. kiiensis larvae. The activity of the anti-oxidative enzymes CAT and SOD, and MT content, changed in response to exposure to these heavy metals in a time and dose-dependent manner, which suggests that these could be biochemical markers of water quality.

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