Heavy metals in Southern Baltic fish: present situation and future trends

Abstract

Herring (Clupea harengus) and cod (Gadus morhua) from three Southern Baltic areas were studied. Mercury content was determined with CV AAS and assays of the remaining metals were carried out with flame AAS. A correlation between the fishing area and contents of Hg, Cd, Cu, and Zn in fish tissues was revealed. Interspecific differences are considered as well. A noticeable decrease in Hg, Cd, Pb, and Cr and an increase in Cu and Zn can be observed over the recent several years in certain organs of herring and cod. In most cases, the changes taking place are better described by curvilinear (logarithmic) equation than by a linear one. Correlations between contents of different metals in fish organs were detected, which points out to interactions between the metals during their uptake and release.