金属の複合影響考

抄録

Metals are ubiquitous, and environment is a cocktail of them. There has long been concern that even if the toxicity of individual metals is low, a risk by the sum of all toxic effect by the individual metals cannot be neglected. A very large number of studies for the toxic effect of metal mixtures have been conducted. Not only in metal mixture, but also in chemical mixture in general, the first task to understand the mixture effect is to test that the mixture effect can be predicted by Loewe’s additivity. The test is made by toxicity test with concentration of two and more chemicals satisfying a prediction model by Loewe. The toxicities of individual metals are well predicted by the Biotic Ligand Model (BLM). A brief description of the model is presented in this article at first. The model is then extended for the prediction of the toxicity of metal mixture. By analyzing the extended model, it is revealed that the standard concentration setting satisfying the Loewe’s additivity is not suitable to detect the additivity. The result implies that we do not know enough about the toxic effect of metal mixtures because almost all concentrations in the previous tests were set to satisfy Loewe’s additivity.