土壤浸提液中重金属对发光杆菌T3的毒性效应

摘要

通过测定掺杂pb2+、Zn2+、Cd2+、Cu2+和Cr3+的土壤浸提液中明亮发光杆菌T3的抑制率,研究重金属复合污染对明亮发光杆菌T3的生物毒性效应.按照重金属离子等效应浓度配比的原理,设计均匀试验,用逐步多元回归法构建土壤水浸提液中重金属( Pb2+、Zn2+、Cd2+、Cu2+和Cr3+)浓度(Xi)与发光菌抑制率(Y)的响应关系:Y=(-39.596±15.811)- (6.633±0.802)×(-lgXCu)(- lgXzn)+ (59.466±8.731)×(-lgXCd)(-lgXCr).该模型具有较好的拟合优度(F检验和t检验的P＜0.05),模型校正后的决定系数(R2adj)为0.933.内部样本验证表明,发光菌抑制率的预测值与试验值相对偏差最大为8.6％,说明该模型具有较好的预测能力.机理分析显示,Cu2+和Zn2+交互体现为拮抗作用,Cd2+和Cr3+交互体现为协同作用,故在重金属复合污染控制方面,有必要进一步研究Cu2+和Zn2+拮抗作用对降低复合毒性的贡献.%Toxicity effects of composite pollution of heavy metals to Photobacterium phosphoreum were studied through determining the inhibition rate of Photobacterium phosphoreum in the extraction solutions of soil doped with Pb 2+, Zn2+ , Cd2+ , Cu2+ and Cr3+. The response relation [Y=( -39.596 ±15. 811) - (6.633 ±0. 802)×( -lgXCu)( -lgXZn + (59.466 ±8. 731) ×( -lgXCd)( -lgXCr)] was developed between concentration of Pb2+ , Zn2+ , Cd2+ , Cu2+ and Cr3+ in extraction solutions of soil and the inhibition rate of Photobacterium phosphoreum based on the uniform experimental design, with the principle of equivalent-effect concentration ratio method and the multiple stepwise regression. The model had significant goodness-of-fit with advantages in F-test and t-test (P < 0.05) and a high adjusted correlation coefficient (Radj2 = 0.933). The results in the internal sample validation indicated that the maximum of relative deviation between experimental and calculated values of the inhibition rate was 8. 6%. The mechanism analysis showed that the interaction between Cu2+ and Zn2+ was antagonistic effect; while the interaction between Cd2+ and Cr3+ was synergistic effect. The findings of this study underlined the necessity of further research on the antagonistic effect between Cu2+ and Zn2+ to reduce composite toxicity in heavy metal pollution control.