Assessment of PCB and chlorinated pesticide accumulation in mussels at Kaštela Bay (Eastern Adriatic).

The biological response of mussels Mytilus galloprovincialis, resident and transplanted to cages, to contamination with anthropogenic pollutants from Kaštela Bay, located in the central part of the eastern Adriatic coast, was investigated. The main purpose of this paper is to trace the accumulation of PCBs and chlorinated pesticides (HCB, lindane, heptachlor, aldrin, p,p'-DDTs) as a direct measure of potential contaminant availability to organisms, in a period from 2000 to 2011. In order to do so, cultured mussels (Mytilus galloprovincialis) of the same size and age were transplanted from the unpolluted Mali Ston Bay to the Kaštela Bay. Sampling was performed bimonthly, and the level of target contaminants in whole soft tissue was determined. After two months of exposure, the concentration of PCBs in transplanted mussels increased on average 6.5-times, and of DDTs 2-times, while the intensity of changes for HCB, lindane, heptachlor and aldrin was negligible. Seasonal variation of pesticide content was similar without a significant change throughout the experimental period, while that of PCBs was somewhat different showing increased accumulation in summer. Seasonal and spatial variation of organochlorines in the Kaštela Bay was likely the result of prevailing environmental rather than biological parameters. In accordance with prevailing hydrodynamic cycling, contaminant concentration decreased in acyclonic direction towards the exit of the Bay. Measurement of target contaminants in resident mussels sampled from the most contaminated area of the Bay exhibited decreasing concentrations of lindane, aldrin and p,p'-DDTs. However, PCBs exhibited statistically significant increasing concentrations in relation to the slightly increasing concentrations of HCB. With regard to human health, organochlorine (OC) levels in the mussel tissue were below prescribed limits for human consumption.