Distribution of heavy metals in seaweeds collected along Marsa-Matrouh beaches, Egyptian Mediterranean Sea

The distribution of Cd, Cu, Fe, Ni, Pb, and Zn concentration in two seagrass species in addition to six species of marine macro algae: Cystoseira sp., Gelidium crinale, Laurencia obtusa, Gracilaria verrucosa, Jania rubens, and Enteromorpha compressa collected along Marsa-Matrouh coastal waters (Egypt) were determined by Flame Atomic Absorption Spectrometry. The recovery study was carried out using a certified reference material NMIJ CRM 7405-a. The obtained heavy metal contents indicated that different species demonstrated various degrees of metal accumulation. In general, El-Boussit station recorded the highest concentrations among the all studied stations. There was a positive correlation between Fe concentrations in the seaweeds and those of Cu and Pb indicated the same source of these metals and/or synergistic interaction between these metals. In general, as regards the influence of the collection sites on the whole metal accumulation, El-Boussit is considered to be the most polluted. There was a positive correlation between Fe concentrations in the seaweeds and those of the Cu and Pb, in addition to negative correlations between Cu and Ni, Pb and Zn. On the basis of the levels of trace elements observed in Posidonia oceanica and Cymodocea nodosa besides their wide distribution in Marsa-Matrouh beaches; these two species are considered to be good bio-indicators for metals in the area of investigation.