PBBs and PBDEs are brominated flame retardants, which are used in several materials, such as plastics from tv's and computers, textiles, interiors of cars and aeroplanes, etc. They reduce the risk of combustion and the expansion of an existing fire. PBBs and PBDEs are persistent organic pollutants. They are both lipophilic molecules, resistent to degradation. As a result of these characteristics they persist in the environment. PBBs and PBDEs can be found everywhere, even in areas at great distance of human activity, such as the North Pole. PBDEs are being produced in large amounts. One of the factories that produces PBDEs in Europe, is located in Terneuzen, near the River Schelde. In this study, samples of gudgeon (Pomatoschistus minutus), flying crab (Liocarcinus holsatus) and common starfish (Asterias rubens) were taken in 7 locations for both the BCP and the SE. By means of Soxhlet extraction the fat and the lipophilic compounds were extracted, after which the present PBDEs and PBBs were analysed with a GCIMS. No PBBs were found in the samples and in all samples taken 6 out of the 7 PBDEs monitored were detected. There was a large difference in concentrations between the BCP and the SE: levels in the SE were up to 25 times higher than the levels in the BCP. The highest concentrations were recorded for the locations near the Ghent-Terneuzen-chanel and near Antwerp. These elevated concentrations probably arise from the pollution caused by the production of PBDEs in Terneuzen and other possible sources, such as the textile industry in Antwerp. Some locations in the North Sea near industrial activity, as the harbour of Zeebrugge, can be distinguished from the other locations further at the sea. Except for the differences between the locations, there are also differences present between the distinct species. The highest concentrations are found in the crab, followed by the starfish and the gudgeon. There are also differences observed in the congeneric distribution between species from the BCP and SE. From the records of this study, one can clearly see a decreasing gradient in the organisms from Antwerp to the North Sea, due to the pollution sources further upstream. In other studies it has been noticed that PBDEs show bioaccumulation. The concentrations detected in animals from the lower trophic levels, such as the crab, the starfish and the gudgeon, are rather high, especially in the SE. Therefore, the levels in predators at the top of the food chain must be even higher. Moreover it's expected that the levels present in the environment will increase even more in the future. |
