Toxicity of dietary methylmercury to fish: derivation of ecologically meaningful threshold concentrations

Threshold concentrations associated with adverse effects of dietary exposure to methylmercury (MeHg) were derived from published results of laboratory studies on a variety of fish species. Adverse effects related to mortality were uncommon, whereas adverse effects related to growth occurred only at dietary MeHg concentrations exceeding 2.5 m gg � 1 wet weight. Adverse effects on behavior of fish had a wide range of effective dietary concentrations, but generally occurred above 0.5 m gg � 1 wet weight. In contrast, effects on reproduction and other subclinical endpoints occurred at dietary concentrations that were much lower (