| Popis: |
The Kastela Bay, one of the polluted areas on the eastern Adriatic coast, has been of interest for the investigation of the level of contamination by polychlorinated biphenyls (PCBs). In order to assess the level, a monitoring programme was performed, using two different age groups (1 and 2 year) of mussels (Mytilus galloprovincialis), which were transplanted from an unpolluted area to four locations in the Bay. This paper presents results of the measurements undertaken in January and July 2002. The average concentration of total PCBs (expressed by the reference to Aroclor 1254 and 1260) in the soft tissue of all mussels from the Bay (61 ng/g d.w.) was much higher (7.6 times) than at the location of their origin. PCBs concentration was higher in the winter (1.3 times) than in the summer season, which might be related to the higher water mass dynamics and resuspension of sediments. The dominant congeners in all samples were 153 and 138, which is related to their highest persistence among the PCB congeners. Regarding the spatial distribution, the highest concentration values were found in mussels from the eastern part of Kastela Bay, which is under the influence of urban and industrial wastewater, and urban runoff discharges. A statistical analysis of the obtained data showed a high correlation between the total PCBs concentration and six individual PCB congeners. Furthermore, it was found that the concentration depends on the age of mussels (average value in one year mussels was 67 ng/g d.w., comparing to 54 ng/g d.w. for 2 years mussels), which is in the correlation with the lipid content. This points out that the monitoring data could not be easily compared when the biondicator organisms are not of the same age. |
