Bioaccumulation of Heavy Metals in Cetaceans and Fish from the Bulgarian Black Sea Coast

The accumulation of heavy metals in animal tissues is an important factor in monitoring the health of any marine ecosystem, and the Black Sea is no exception. The use of aquatic organisms as bioindicators of heavy metal pollution is common in studies, and molluscs and fish are some of the most used indicators, unlike cetaceans, which are not common. The objective of the present study is to determine the accumulation of five heavy metals (Pb, Cd, Zn, Cu, Ni) in the living tissues of three cetacean species, six fish species part of the cetacean diet, and seawater of the Bulgarian Black Sea coast. Heavy metal concentrations were analyzed using an Atomic Absorption Spectrophotometry and the results were used to calculate the bioaccumulation factor (BCF) and the biomagnification factor (BMF). The results are analyzed in a comparative plan between the northern and southern part of the Bulgarian coast. In all biota samples, the concentration of Zn was the highest. No statistical differences were found between fish and cetacean samples from the two study areas. Cetaceans have a higher BCF for Cd, while fish for Pb, and the BMF for cetaceans was confirmed for the elements Cd and Zn.