Modelling of the Joint Toxicity of Heavy Metals (Ni~(2+), Co~(2+), Cr~(3+) and Pb~(2+)) on Photobacteria Based on the Factorial Experiment (2~4)

摘要

The joint toxicity of heavy metals (Ni~(2+), Co~(2+), Cr~(3+), Pb~(2+)) and trends in toxicity were analysed by multiple linear regression and back propagation-artificial neural network models, using photobacteria as an indication organism in factorial experiments. The joint toxicity of Ni~(2+), Co~(2+), Cr~(3+) and Pb~(2+) mainly occurs through multiple interactions. Interactions between Ni~(2+), Co~(2+) and Cr~(3+) weaken the single toxicity and binary interaction of Pb~(2+). Binary or quaternary heavy metal mixtures exert mainly antagonistic effects, while ternary interactions are mainly synergistic. Increased concentrations of Pb~(2+), Cr~(3+) and Ni~(2+) corresponded with increased toxicity of the mixed system, but Co~(2+) showed the opposite trend. The toxic effects of the mixed system were greatest with high Cr~(3+) concentration, while Pb~(2+) exerted the smallest effect.