Assessment of relative toxicity of chlorinated dibenzo- [formula omitted]-dioxins, dibenzofurans, and biphenyls in Lake Ontario salmonids to mammalian systems using toxic equivalent factors (TEP)

Abstract

Concentrations of chlorinated dibenzo-p-dioxins and dibenzofurans were measured in four species of Lake Ontario salmonids and related to congener-specific PCB analyses for the same fish reported in a previous study. The toxicity of these chemical concentrations to mammalian systems were evaluated using toxic equivalent factors (TEF), based on composite, AHH induction, and thymic atrophy indices. The results indicated the PCB levels monitored in these species are potentially 5 to 10-fold, or more, toxic to mammals than the levels of dioxins or furans.