Distribution and relationships of mercury, lead, cadmium, copper and zinc in perch (Perca fluviatilis) from the Pomeranian Bay and Szczecin Lagoon, southern Baltic

The concentrations of selected metals, such as Hg, Cd, Pb, Cu and Zn, were determined in muscle and liver of perch (Perca fluviatilis) from the Pomeranian Bay and Szczecin Lagoon, southern Baltic. The concentrations of Hg in muscle and Cd, Pb and Cu in liver increased with the age of the specimens analysed. The positive relationship between muscle Hg and age (weight-length) is probably attributed to the specific bioaffinity for organic matter of CH3Hg with a high biological half-life, which generally constitutes the dominant pool of the total Hg in the fish muscle. ANOVA analysis clearly demonstrated that in the Pomeranian Bay there were significant seasonal variations of muscle Hg and hepatic Cd, Pb and Cu. Factor analysis supported seasonal differences in muscle and especially hepatic samples; specifically, summer muscles were clearly separated from winter ones. Muscle samples corresponding to the winter season had relatively high concentrations of Hg Cd and Pb. The concentrations of muscle Hg (corresponding to 70–105 μg CH3Hg eaten weekly) are comparable to the PTWI (permissible tolerable weekly intake) recommended by WHO (200 μg CH3Hg). The muscle Cd and Pb levels are significantly lower than the PTWIʹs and do not constitute any threat for man.