Metal bioaccumulation and oxidative stress in yellow perch (Perca flavescens) collected from eight lakes along a metal contamination gradient (Cd, Cu, Zn, Ni)

Abstract

Links among metal exposure, metal accumulation, and metal-induced effects were explored in indigenous yellow perch (Perca flavescens) collected from eight lakes located along a metal concentration gradient in two mining regions. Fish exposure to Cd, Cu, Ni, and Zn was estimated on the basis of calculated free metal ion concentrations in lake waters. Hepatic metal concentrations were determined and various markers of oxidative stress were measured to assess metal effects in liver cells. Accumulated metals were not consistently related to ambient free metal ion concentrations, possibly because of unaccounted for fluctuations in lake water metal concentrations. Accumulated metals were associated with limited oxidative stress in perch livers, as evidenced by reductions in glutathione concentrations and glutathione reductase activities. However, this stress appeared to be minor, since increasing hepatic Cu concentrations were associated with reduced lipid peroxidation, a response opposite to that predicted from basic principles. Our results suggest that oxidative stress will not have direct repercussions on the health of the perch at the individual level. We speculate that the observed increase in metallothionein concentrations with increasing accumulated metals might afford protection against reactive oxygen species.