Mercury in Nonmarine Birds and Mammals

Abstract

This chapter describes the available data for different dietary, tissue, and egg concentrations. It summarizes the adverse effect concentrations obtained for different species as geometric means and ranges. Birds and mammals with the highest liver-mercury concentrations often have the lowest methyl mercury (MeHg) fraction, despite being primarily exposed to MeHg. The data for the dietary concentrations of Hg associated with lethality in mammals are more limited than that for birds. Analysis of the data from the earlier studies indicates that, when Hg is in an organic form in the diet, the geometric mean dietary Hg concentration associated with lethality is 20 mg/kg and 4.3 mg/kg in birds and mammals, respectively. The range of liver concentrations that have been associated with impaired reproduction is relatively wide, and overlaps that associated with lethality, but the data suggest that liver concentrations in adult birds exceeding 2 mg/kg may be associated with adverse effects on reproduction.