氯苯对球形红细菌的毒性效应研究

Toxic effect of chlorobenzene on Rhodobacter sphacroides growth

研究不同质量浓度氯苯对光合细菌球形红细菌(Rhodobacter sphaeroides)生长和脱氢酶活性的影响。结果发现,当氯苯质量浓度达到80mg/L时,即可抑制球形红细菌的生长;当氯苯质量浓度增加到1000mg/L时,球形红细菌的生长被完全抑制。球形红细菌脱氢酶活性随氯苯质量浓度增加而明显降低。在此基础上进一步运用化学品对水生生物急性毒性实验的标准方法研究了氯苯对球形红细菌的毒性效应。结果表明,氯苯对球形红细菌生长的安全质量浓度(最低可见效应质量浓度LOEC)为40mg/L。抑制球形红细菌生长的96h-EC50为346.7mg/L。氯苯与球形红细菌的质量浓度-效应方程为y=11.1459-2.416x,R2=0.9897。对该质量浓度-效应方程进行χ2检验表明,结果符合精度要求,计算出的96h-EC50真实可靠。

The paper is actually a report of the authors＇ study on the toxic effect of chlorobenzene（CB） on photosynthetic bacteria and the relation between the concentration of CB and the dehydrogcnase activity of Rhodobacter sphaeroides. As is known, chlorinated benzenes are widely used as solvents in chemical reactions, such as in dissolving oils, waxes, resins, greases, as well as rubber, so are also used in the production of herbicides and pesticides. Nevertheless, no report has been made on their use for wastewater treatment. In hoping to lay a foundation of water quality evaluation and the sewage treating with Chlorinated benzenes, we have studied the Rhodobacter sphaeroides growth and their dehydrogenase activities under different concentrations. The experiments of ours discover that when the CB concentration was 80 mg/L, the growth of Rhodobacter sphaeroides was inhabited. And, when its concentration reached 1 000 mg/L, its growth would completely be inhabited. Thus, it can be deduced that, with the increase of the concentration of CB, their dehydrogenase activity would be degraded bit by bit. If a standard method of algal bioassay for evaluating the toxicity of toxic chemicals is applied in the experiments, it would result in the lowest observed effect of their concentration（LOEC） on the growth, that is, 40 mg/L, on the contrary, the 96 b-EC50 of CB on the inhibition of their growth was 346.7 mg/L. Thus, it can be concluded that the linear regression equation of the logarithm with the concentrations of CB and probability unit should be： y = 11.1459 - 2.416x, R^2 = 0.989 7. By means of the probability unit for data treatment, the results prove to be precise from the Z= test of concentration-response equation 96 h-EC50.