6种重金属的发光菌毒性效应及其海洋生物物种敏感度分析

以明亮发光杆菌(Photobacteriumphosphoreum)为受试生物,采用微孔板毒性测试法,测定6种重金属化合物的发光抑制毒性并对毒性数据进行非线性拟合和预测,结果表明ZnSO47H2O、K2Cr2O7、HgCl2、CdCl22.5H2O和Pb(NO3)25种重金属化合物的毒性作用关系均可以用Weibull模型有效描述,CuSO45H2O的毒性作用关系可用Logistic模型有效描述。几种重金属的毒性顺序为K2Cr2O7 CuSO45H2O CdCl2 Pb(NO3)2 ZnSO47H2O HgCl2。明亮发光杆菌对6种重金属离子的EC50值分布在由其它海洋生物毒性效应值拟合的物种敏感度分布模型范围内。与海洋鱼类、蚤类、贝类和虾蟹类相比,明亮发光杆菌对Cu2+的毒性灵敏度较差,但是对Cd2+、Pb2+、Hg2+、Zn2+、Cr6+5种重金属离子的毒性灵敏度较高,多数海洋生物对6种重金属的毒性响应顺序与明亮发光杆菌一致,说明发光菌毒性测试法对于海洋环境重金属污染的生态毒理效应具有重要预测价值。

Toxicity effectofheavy metals on Photobacteriumphosphoreum and the species sensitivity comparison with other marine organisms

Heavy Metal toxicities are assessed with Photobacteriumphosphoreum and the dose-response curvefor ZnSO47H2O, K2Cr2O7, HgCl2, CdCl22.5H2O and Pb(NO3)2 can be described by Weibull model while for CuSO45H2O can be described by Logistic model in which the values of Log2EC50 were easily predicted. The P.phosphoreum was most sensitive to Hg, followed by Zn, Pb, Cd, Cu, andthe least sensitive to Cr. The EC50 of the P. phosphoreum fell within the scope of the species sensitivity distribution model predicted with other marine organisms. Compare to fish, daphnia, decapods and bivalves, P. phosphoreum is at a low level of sensitivity to Cu2+, but at higher levels of sensitivities to Cd2+, Pb2+, Hg2+, Zn2+ and Cr6+. Most of the marine species have the same order of the response to the six different heavy metals, indicating that toxicity testusing P. phosphoreum is very important for predicting heavy metal effects in marine ecosystem.