Bioaccumulation of Cadmium and Copper in Different Areas of The Eastern Part of The Gulf of Finland

Abstract

The Gulf of Finland (with the estuary of the Neva River) is located in the northeastern part of the Baltic Sea and plays a key role in the formation of biological resources and the quality of the natural environment of the entire Baltic Sea. Along with eutrophication, its ecosystem is subject to anthropogenic pollution with toxic elements, including heavy metals. In this work, we analyzed the content of cadmium and copper in bottom sediments of the Gulf of Finland and in the tissues of the dominant species of benthic macrofauna — the deposit-feeder polychaete Marenzelleria arctia and the predatory isopod Saduria entomon. Significant variability was found in the spatial distribution of these elements in both environments. The average concentrations of cadmium (0.67±0.1 mg/kg of dry matter) in bottom sediments were correspondingly two times higher, and copper (34.4±4.0 mg/ kg) 1.5 times lower than the threshold levels established for the Baltic Sea. A significantly higher content of these metals was found in the tissues of isopods than polychaetes; in some locations it is an order of magnitude higher in isopods than in polychaetes. The factor of trophic transfer of metals in the Gulf food web showed biomagnification, i. e. accumulation of metals during the transition from low-level consumers (M. arctia) to predatory consumers (S. entomon), cadmium by 3.7 times and copper by 8.7 times. Thus, both species of benthic animals have high accumulative activity in relation to cadmium and copper, which contributes to the active transport of both metals from bottom sediments to marine biota, and, ultimately, transfer to the higher levels of the food web (fish, birds and mammals).