Residue-based mercury dose-response in fish: an analysis using lethality-equivalent test endpoints.

Dose-response relationships for aquatic organisms have been developed for numerous contaminants using external media exposures (water and sediment). Dose-response relationships based on internal concentrations (tissue residues) are limited. The present study reports Hg dose-response curves for early life stage and juvenile or adult fish based on published tissue-residue toxicity studies. These curves rely primarily on endpoints that can be directly related to mortality, such as survival, reproductive success, and lethal developmental abnormalities. These lethality-equivalent endpoints were linked using the common metric of injury. Uncertainties and potential applications of this mercury dose-response curve are discussed. Major uncertainties include lab to field extrapolations, biological endpoints selected by investigators, interspecific extrapolations, and the paucity of published early life stage residue (dose)-response information. To the extent this curve is based exclusively on laboratory toxicity tests and does not consider other potentially sensitive and ecologically important biological endpoints (e.g., growth and behavior), the magnitude of the adverse effects predicted by the curve may be underestimated.