Influence of lake chemistry and fish age on cadmium, copper, and zinc concentrations in various organs of indigenous yellow perch (Perca flavescens)

Abstract

Concentrations of Cd, Cu, and Zn were determined in various organs of juvenile yellow perch (Perca flavescens) collected from eight lakes located along a metal concentration gradient. Metal exposure was evaluated on the basis of the free ambient Cd²⁺, Cu²⁺, Zn²⁺, and Ca²⁺ concentrations, as estimated from chemical equilibrium simulations using the ambient water chemistry data. Based on regression analyses, lake water Ca²⁺ and H⁺ did not significantly influence the steady-state metal concentrations in various body parts of yellow perch. Cadmium concentrations were significantly higher in the gastrointestinal tract than in the gills, suggesting that uptake of this metal from food is more important than uptake from water. Variations in the contribution of each organ to the total Cd and Cu burdens revealed a possible dysfunction in liver excreting capacities in the fish from the most highly contaminated lakes. Additionally, measurements on yellow perch from 0 to 10 years old (N = 81) collected from a single lake suggest that Cd concentrations in some organs increase with fish age, which we interpret to be linked to changes in fish growth rate with age.