【摘要】 运用评价化学品对水生生物毒性的标准方法,得到Pb2+、Cd2+和Cr(Ⅵ)对球形红细菌生长的最小无差异浓度(LNOEC)分别为85.9mgL-1、22.1mgL-1和17.7mgL-1.根据实验结果采用几率单位进行数据处理,得到抑制球形红细菌生长的96hEC50分别为195.0mgL-1、91.2mgL-1和77.6mgL-1,并对各剂量反应方程进行χ2检验,结果均符合精度要求,计算出的96hEC50真实可靠.研究结果表明,抑制球形红细菌生长的毒性由大到小的顺序是Cr(Ⅵ)>Cd2+>Pb2+.不同金属离子与细胞壁亲和性不同或能通过菌体内生物化学转化形成沉淀,可能是导致金属离子抑制球形红细菌生长毒性差异的主要原因.图1表2参15更多还原

【Abstract】 A standard method of algal bioassay for evaluating the toxicity of toxic chemicals was applied in experiments. The lowest no observable effect concentrations (LNOEC) of Pb 2+, Cd 2+ and Cr (Ⅵ) on the growth of Rhodobacter sphaeroides were found as 85.9 mg L -1, 22.1 mg L -1 and 17.7 mg L -1, and 96 h-EC_ 50 of lead, cadmium and chromium on inhibition of the growths of R. sphaeroides were calculated as 195.0 mg L -1, 91.2 mg L -1 and 77.6 mg L -1 respectively using the method of probability unit for data treatment based on the test results. The results from the χ 2 test of each dose-response equation showed that 96 h-EC_ 50 calculated were all precise and credible. It was found that the toxicities of these metals on inhibiting the growth of R. sphaeroides were increased in the order of Cr (Ⅵ)>Cd 2+>Pb 2+. The different affinities between different metal ions and extracellular biopolymer were mainly responsible for the different inhibitions of R. sphaeroides. Fig 1, Tab 2, Ref 15更多还原