Sources of variability in trace metal bioaccumulation by fish

Abstract

Bluegill and channel catfish were collected in 1982 from metal-contaminated Peak Creek, Virginia. Whole-body and tissue concentrations of cadmium, lead, and zinc were determined by atomic absorption spectrophotometry. Variations in metal concentrations within each species were related to duration of exposure (age). Whole-body metal concentrations showed consistent relationships with age in both species: lead concentrations were positively correlated and zinc levels were negatively correlated with age. Cadmium and lead concentrations in liver, kidney, and bone tissues displayed variable relationships with age; zinc concentrations generally showed negative correlations with age in tissues of both species.

Interspecific variations were investigated in bluegill and channel catfish from Peak Creek, and by a literature review of site-specific, multispecies comparisons of accumulated levels of cadmium, lead, and zinc. Habitat differences among species influenced metal accumulation; sediment-dependent species showed generally higher metal concentrations, although this relationship was not evident for the species from Peak Creek. Trophic status was inversely related to metal concentrations; organisms from higher trophic levels usually displayed low metal concentrations. Species differences in the proportion of various tissues were not accountable for interspecific variations in whole-body metal concentrations, but tissue proportions in fish species seldom have have been reported. Differences among species in physiological mechanisms of metal uptake/excretion appeared to be major sources of variation in metal accumulation. Results suggest that older specimens of benthic detritivorous fishes should be used in surveys of metal pollution to accurately express the degree of cumulative contamination in aquatic ecosystems.