部分重金属化合物对淡水发光菌的毒性研究

应用微板毒性分析方法,分别测定了CdCl2·2.5H2O、CoSO4·5H2O、Cr(NO3)3·3H2O、Cu(NO3)2·3H2O、Fe(NO3)3·3H2O、MnCl2·9H2O、Na2SeO3、ZnSO4·7H2O、Ni(NO3)2·6H2O9种重金属离子化合物及其混合物对淡水发光菌—青海弧菌Q67(Vibrio-qinghaiensissp.—Q67)的发光抑制毒性.结果表明,9种重金属离子化合物对Q67的剂量-效应关系均可用Weibull或Logit模型有效描述.由拟合剂量-效应曲线得到这9种重金属离子化合物的半数效应浓度EC50的负对数值(-logEC50)分别为4.35、3.08、2.39、3.83、3.34、2.39、3.32、3.93和2.76,说明其毒性顺序为:CdCl2·2.5H2O>ZnSO4·7H2O>Cu(NO3)2·3H2O>Fe(NO3)3·3H2O>Na2SeO3>CoSO4·5H2O>Ni(NO3)2·6H2O>Cr(NO3)3·3H2O≈MnCl2·9H2O.为了研究重金属混合物的毒性规律,设计了4组等效应浓度(EC50、EC15、EC10和EC5)比混合物,测试了其混合物毒性,并应用剂量加和(DA)、独立作用(IA)原理及经典联合毒性评价方法进行了分析.DA与IA分析表明,所研究的4种混合物的毒性具有拮抗特征,而毒性单位法(TU)和混合指数法(MTI)的评价结果均为部分相加作用,相加指数法(AI)的评价结果则为拮抗作用.所选评价方法不同,混合物毒性评价结果可能也不同.

Toxicities of Selected Heavy Metal Compounds and Their Mixtures to Photobacteria( Vibrio-qinghaiensis sp. —Q67)

Using the microplate toxicity analysis, the toxicities of 9 heavy metal compounds(HMCs)including CdCl2·2.5H2O, CoSO4·5H2O, Cr(NO3)3·3H2O, Cu(NO3)2·3H2O, Fe(NO3)3·3H2O, MnCl2·9H2O, Na2SeO3, ZnSO4·7H2O, and Ni(NO3)2·6H2O inhibiting the luminescence of a freshwater photobacteria, Vibrio qinghaiensis sp.─Q67 were determined respectively. Results showed that all dose-response relationships of nine HMCs can be described by Weibull or Logit model. From the dose-response curves(DRCs)fitted by the nonlinear least square technique, the values of-logEC50 or pEC50 of the HMCs were easily obtained. The values indicated a toxicity order of CdCl2·2.5H2O(pEC50=4.35)>ZnSO4·7H2O(3.93)>Cu(NO3)2·3H2O(3.83)>Fe(NO3)3·3H2O(3.34)>Na2SeO3(3.32)>CoSO4·5H2O(3.08)>Ni(NO3)2·6H2O(2.76)>Cr(NO3)3·3H2O(2.39)≈MnCl2·9H2O(2.39). To explore the joint toxicity between the HMCs, four mixtures consisted of nine HMCs were designed using equivalent-effect concentration(EC5,EC10,EC15, and EC50)ratio method. The toxicities of the mixtures were evaluated by dose-addition(DA) and independent action(IA)as well as some traditional methods such as the Toxicity Unit(TU), Mixtures Toxicity Index(MTI), and Additive Index(AI). The results from the DA/IA showed the antagonistic effects, and AI also showed the antagonistic effects, while, TU and MTI showed the partial additive effects.