铅锌冶炼厂废水对鱼类危害的调查

AN INVESTIGATION ON THE DEFORMITY AND MORTALITY OF FISH CAUSED BY POLLUTED WATER FROM THE ZINC AND LEAD SMELTERY

本文报道了铅锌冶炼厂废水中所含有的铜、锌、铅、镉污染物对鱼类的毒性调查。初步查明了污染物在不同季节、气温条件下引起鱼类死亡、畸变的影响。通过调查分析发现,污染区鱼体重金属含量显著高于对照区;畸变鱼高于未畸变鱼。畸变鱼体内四种重金属含量的顺序是锌>铜>铅>镉,与水中含量顺序一致。畸变鱼体内镉的含量比对照区高18倍,从而认为镉与畸变可能有密切关系。鱼体的不同部位四种重金属含量有明显差异,值得进一步探讨。

Four heavy metals--copper, zinc, lead and cadmium were found in the dischargedwater from the lead and zinc smeltry. These four heavy metals remain a rather highcontent in the water all the year around. Most of them was deposited in the silt of theriverbed, it is considered to be the potential harmfulness to fish. These heavy metals gradually accumulate in planktons and then transfer to the fish body. The coeffcientof acamulation is Zn = 1. 6×10~4, Cu =1. 9×10~3, respectively. The content of lead andcadmium in the fish body is not less than 10~4.The ratio of the content of the four heavy metals in the body of the deformedfish is Zn: Cu: Pb: Cd = 59: 10: 3: 1. The content of cadmium in the deformed fish waseighteen times higher than that in the controlled group. This shows that the highconcentration of cadmium may be the causal factor of the deformation of fish.The experiment has proved that the pernicious heavy metals in the waste waterdischarged from the smeltery have toxic effects on fish. When the water contains1.4% in volume, the TLM of the experimental fish is 48. When the content of zincis high above 1 .5mg/l, fish will die in acute poisoning and the content of zinc andcadmium reach to 0. 25mg/l and 0. 0125mg/l, respectively, the symptoms of ataxia inswimming, paralysis and deformation will appear. Zinc has a quick toxic effect,always cause high mortality. Cadmium has a great effect on deformation. The mixedsolution of Zn and Cd has a combined effect on fish.