利用拓展生物配体模型预测Mg影响下Cu-Ni、Zn-Ni对小麦的联合毒性

通过水培实验,研究了不同Mg2+浓度下Cu、Zn、Ni单独及Cu-Ni、Zn-Ni复合对小麦根的毒性并分别建立了3个元素的BLM.利用Cu、Zn、Ni单一毒性数据,计算了复合金属离子与生物配体结合数量指数(fmix),由此建立了用于预测Cu-Ni、Zn-Ni联合毒性的BLM-fmix模型.结果表明,溶液中Mg2+浓度增加,能够减弱单一Cu、Zn、Ni和Cu-Ni、Zn-Ni复合对小麦根的毒性.在复合体系中,Cu-Ni复合的TU50(对小麦根长产生50%抑制作用时的毒性单位值)分别为1.18、1.33、1.31,略大于1,表现为弱拮抗作用;而Zn-Ni复合的TU50分别为4.22、2.26、2.16,表现为强拮抗作用.BLM-fmix模型能够准确预测Cu-Ni、Zn-Ni联合作用下小麦根长,预测和实测值的相关系数及标准误差分别为0.94、8.87(Cu-Ni复合)和0.92、10.14(Zn-Ni复合),该结果为重金属复合污染土壤的评价和修复提供理论依据.

Extended biotic ligand model for prediction of mixture toxicity of Cu-Ni, Zn-Ni to wheat effected by Mg

Toxicity of Cu, Zn, Ni alone and Cu-Ni, Zn-Ni compounds to wheat were tested by water cultivation experiment under different concentrations of Mg²⁺, and BLM (biotic ligand model) of Cu, Zn and Ni were established respectively. Using data of single metal element (Cu, Zn and Ni) BLM combined with toxicity index, the overall amounts of metal ions bound to the biotic ligands (f_mix) was calculateed. Furthermore, BLM- f_mix was established to predict the joint toxicity of Cu-Ni and Zn-Ni. The results showed that the toxicity of single Cu, Zn and Ni as well as the combined toxicity of Cu-Ni, Zn-Ni were decreased with the increasing Mg²⁺ concentration. In the compound solution, the TU₅₀ values (when the root length of wheat was inhibited by 50%) of Cu-Ni compound was 1.18, 1.33, 1.31, slightly greater than 1, which showed weak antagonism between Cu and Ni; Whereas in Zn-Ni composite system, the TU₅₀ value was 4.22, 2.26, 2.16, which showed strong antagonistic effect. BLM-f_mix could accurately predict the root length of wheat under the combined action of Cu-Ni and Zn-Ni. The correlation coefficient and standard error of the predicted and measured values were 0.94, 0.87 in Cu-Ni and 0.92, 10.14 in Zn-Ni respectively. The results provided a theoretical basis for the evaluation and remediation contaminated soils of heavy metal.