Polychlorinated biphenyls in sediments from Ghar El Melh lagoon, Tunisia.

The concentrations of 20 Polychlorinated biphenyls (PCBs) were determined in 12 superficial sediments collected from The Ghar El Melh lagoon. Sediment samples were extracted by Soxhlet and analyzed by Gas chromatography with electron capture detector. The concentrations of PCBs, as sum of the 20 congeners, ranged from not detected to 3.987 ng/g on a dry weight basis, with a predominance of highly chlorinated (penta- and hepta-chlorobiphenyls) congeners. No significant correlation was found between the total PCB concentrations and organic carbon content suggesting that sediment organic carbon content did not play an important role in controlling the PCBs levels in the sediments. PCB levels in sediments were compared with Sediments Quality Guidelines (ERM-ERL indexes) for evaluation probable toxic effects on marine organism. The PCBs concentrations were lower than ERM and ERL values for all the collected samples.