Sciences marines : recherche et développement

Abstrait

Determination of some Heavy Metals in Sea-grass ?Poisdonia oceanica?(L.) Delile of Eastern Libyan Coast ?Mediterranean?

Abdulsalam A Benkhayal and Khadija S El-turki

The concentrations of heavy metals (Cr, Co, Zn, Cd, and Pb) were found in the samples of tissues of Seagrass, Posidonia oceanica (L.) Delile, that were collected from eighteen different sites along 820 Km of the coast of eastern Libya on the Mediterranean sea (the first site is about 500 km to the east of Alexandria of Egypt). These samples were collected from the following 18 sites (east to west): Tobrouk, Ras-Etteen, Derna, Ras-Lehlal, Sousa, QasrLibya, Tulmaitha, Deryana, North Benghazi, Alssabri, Family Village (Qaria), Nairowz, Nakheil, Geminis, Sultan, Zuitina, Al-Briga and Ras-Lanouf. The technique used by this study was Flame Atomic Absorption Spectrometry (model novAA300). This study shows that elevated concentrations of Zn, Co, and Pb are found in most samples; particularly, those were collected near the discharge points of city sewages effluent and the power station sites. The concentrations of Cr and Co were very low in all the samples, except for those were collected near the city of Benghazi. The statistical analysis (one-way ANOVA) indicates that the Sea-grass” Posidonia oceanica”(L.) Del. tissues have different levels of metal bioaccumulation, which might be used as a bio monitors for trace metals. The higher values of MPI are recorded for BR and TP that is 121.18 and 124.29, respectively. Perhaps, the high values of MPI for these two sites are due to the high elevated values (387.56) μg /g and (186.40) μg/g of Chromium for both sites (BR & TP). The least values of MPI are obtained for the locations SP, ZU and RH (20.16, 20.96 and 22.20 μg\g), respectively, and this may be explained by the low levels of the five heavy metals ( Cr, Co,Zn,Cd and Pb) in these sampled sites.