Elemental fish tissue contamination in northeastern US lakes: Evaluation of an approach to regional assessment

The approach of the Environmental Monitoring and Assessment Program (EMAP) to monitoring of fish tissue contaminants is shown to have utility for regional assessment, and for discrimination of regional from local contamination. The survey sampling design employed by EMAP can be used to make regional assessments without conducting a complete resource inventory. The Environmental Monitoring and Assessment Program-Surface Waters conducted a survey of 167 lakes in the northeastern United States during 1992 through 1994 and analyzed whole fish composite samples for contaminants, including Al, As, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Se, and Zn. Using fish tissue contaminant consumption risk levels derived from U.S. Environmental Protection Agency hazard assessment models, methylmercury (MeHg) was determined to be the elemental contaminant of regional concern to fish consumers: 26% of lakes contained fish with MeHg exceeding a human critical value of 0.2 mu g/g; 54 and 98% of lakes contained fish with MeHg exceeding wildlife critical values for piscivorous mammals (0.1 mu g/g) and birds (0.02 mu g/g), respectively. The other elements analyzed appeared to be at safe levels on a regional scale, or only of localized concern with regard to human health.