Abstract
In this paper, a Bayesian approach to calculate expected potentially affected fraction of species is presented. Parameters of environmental concentration distributions of chemicals and species sensitivity distributions were estimated by Bayesian statistical models using Markov chain Monte Carlo methods. The values and confidence intervals of expected potentially affected fraction of species were then computed by Monte Carlo simulations from the posterior distributions of the parameters of the environmental concentration distributions and species sensitivity distributions. Our models also considered the difference in sensitivity among taxonomic groups and provided the method to develop standardized species sensitivity distributions in which the difference in the number of ecotoxicity data per taxonomic groups was adjusted. The presented methods would enhance the study of quantitative risk comparison and risk tradeoff analysis of chemicals.
