金属离子鱼类急性毒性研究及对环境标准修订的启示意义

以斑马鱼和孔雀鱼为实验动物,进行了Cu^2＋、Cd^2＋、Zn^2＋和Cr^6＋的鱼类急性毒性试验。结果表明,这四种金属离子对受试鱼的毒性影响比较明显,对斑马鱼、孔雀鱼96 h半致死浓度分别为0.57 mg/L,12.59 mg/L,32.24 mg/L,62.27 mg/L和2.36 mg/L,17.71 mg/L,39.71 mg/L,43.40 mg/L。四种金属离子的毒性大小依次为：Cu^2＋〉Cd^2＋〉Zn^2＋〉Cr^6＋;Cu^2＋、Cd^2＋、Zn^2＋对斑马鱼的影响较大,Cr^6＋则对孔雀鱼的影响较大。结果同时对环境标准的修订具有启示意义,现行的国家《污水综合排放标准》（GB8978-1996）和国家《地表水环境质量标准》（GB3838-2002）对废水和水环境中Cu浓度的要求偏低,在符合国家标准的情况下Cu^2＋在低浓度水平就具有较大的毒性,未来污水排放标准和水环境质量标准在修订中应重视这个问题。

Fish Acute Toxicity of Metal ions and its Inspiration for Environmental Standards Revision

Acute toxicity of Cu^2＋,Cd^2＋,Zn^2＋ and Cr^6＋ on Brachydanio rerio and Poecilia reticulates were studied.The toxicity effects of the four metal ions on experimental fish could be observed obviously,LC50 of Brachydanio rerio and Poecilia reticulates to Cu^2＋,Cd^2＋,Zn^2＋ and Cr^6＋ in 96 h was 0.57,12.59,32.34,62.27 mg/L and 2.36,17.71,39.71,43.40 mg/L respectively.The toxicity sequence of the four metal ions to Brachydanio rerio and Poecilia reticulates was that Cu^2＋ Cd^2＋ Zn^2＋ Cr^6＋.Cu^2＋,Cd^2＋,Zn^2＋ had a high toxicity impact on Brachydanio rerio,and Cr^6＋ had a high impact on Poecilia reticulate.The results also indicated that even at the low level of concentration,Cu^2＋ had a high toxicity effect yet.The limit demand of Cu^2＋ in the existing Integrated Wastewater Discharge Standard and Environmental Quality Standards for Surface Water Quality was low,and the results suggested that special attention should be paid for this issue in the environmental standards revision in the future.