Study Of Acute Toxic Effect Of Zn, Hg And Cr On Siniperca Chuatsi And Hypophthalmichthys Molitrix Embryos

With Chinese economy developed rapidly, environment pollution has become a serious problem which can’t be avoided in people’s production and life. The heavy metal pollution is a common one. Research showed that the heavy metals can not be degraded in the water, only carried out some transformation or diversion. The heavy metals could be gathered in animal’s body and substrate sludge, and exited in the food chain concentration. The animal could get the heavy metals from contaminative water through some ways (e.g. the drinking water, and feed). When the heavy metals reached to a certain quantity in animal’s body which exceeded their own ability of detoxification, the animal’s normal physiological function would be disturbed and destroyed, it would also cause some different degree affections on animal’s physiological and biochemical function, even leaded to death, which would get great damage in production. Besides, the polluted animal could pass the heavy metals through the food chain to the human; the human health would be also threated. In this study, the embryos from two species of Siniperca chuatsi and Hypophthalmichthys molitrix were taken as experimental materials, and three heavy metals of mercuric chloride, zinc sulfate, potassium dichromate were used for the toxicity test to embryos of Siniperca chuatsi and Hypophthalmichthys molitrix, in order to find out the minimum full-lethal concentration, highest non-lethal concentration and median lethal concentration. The experimental goal was to provide some reference of actual value to the sustainable development of animal production.When the water temperature attained20～23℃, the dissolved oxygen content was6.0mg/L, and pH was6.2, the different toxic effects of mercuric chloride, zinc sulfate and potassium dichromate on embryos of Siniperca chuatsi and Hypophthalmichthys molitrix were explored by semi-static biological toxicity test. The results showed that:(1) in the groups of three different concentrations of heavy metals, the hatching rate was significantly lower and the embryonic mortality was significantly higher than that in the control group, the larvae became different degrees of deformity and death. With increasing concentrations of three heavy metals, two fish embryo hatching rates were getting lower and lower, showing significant downward trend. Larval deformity and mortality rates were getting higher and higher, showing a significant upward trend. It showed that concentrations and toxicity of three kinds of heavy metals had a significant dose-response relationship.(2) After processing the experimental data by the Karber, it was found out the LC50and SC of the three kinds of heavy metal:in Siniperca chuatsi, the semi-lethal concentrations of zinc sulfate in24h and48h were3.48mg/L and2.75mg/L, and the safe concentration was0.52mg/L; the semi-lethal concentrations of mercury chloride in24h and48h were0.1mg/L and0.07mg/L, and the safe concentration was0.01mg/L; the semi-lethal concentrations of potassium dichromate in24h and48h were197mg/L and140mg/L, and the safe concentration was21mg/L. In Hypophthalmichthys molitrix, the semi-lethal concentrations of zinc sulfate in24h and48h were6.25mg/L and5.24mg/L, and the safe concentration was1.1mg/L; the semi-lethal concentrations of mercury chloride in24h and48h were0.02mg/L and0.08mg/L, and the safe concentration was0.01mg/L; the semi-lethal concentrations of potassium dichromate in24h and48h were372mg/L and248mg/L, and the safe concentration was33mg/L.(3) According to the experimental results, the toxic strength of three heavy metals on embryos of Siniperca chuatsi and Hypophthalmichthys molitrix was in turn:mercury chloride> zinc sulfate> potassium dichromate.(4)The experiment showed that three kinds of heavy metals existed toxicity differences between newly hatched larvae of Siniperca chuatsi embryos and Hypophthalmichthys molitrix embryos. It had differences of species in toxicity of zinc and chromium on the embryos and larvae of two species, and the toxicity of mercury on embryo and larva of two species with no interspecific differences. Therefore, heavy metals should be given strict control in the production environment, especially regard to the harmful heavy metals liked mercury and other toxic heavy metals in which there were no differences of species.