Ecological Risk Assessment of Heavy Metal Pollution in Top soil of Mediterranean Coast: A Case Study of Mareotis Coast, Egypt

The present study was conducted in Mediterranean coastal area to determine the soil contamination by heavy metals as well as their accumulation using halophytes. Sixteen sites were selected along the study area, topsoil samples and plant species were taken and then transferred to the laboratory for metal analyses. Results revealed that the order of metal concentration in total and available form of the soil was as follow; Fe > Pb > Cr > Ni > Cd > Co. The average concentration of Cd and Pb are within the Canadian soil quality guidelines (CSQG) and European Union Standards (EU) limits, but more than those for average upper earth crust (AUEC). While Ni, Co and Cr are more than the limits of CSQG and AUEC. The contamination factor of heavy metals is decreased in the following order: Cd > Cr > Pb > Ni > Co > Fe and the enrichment factors of studied metals showed that their sources were from anthropogenic impacts. The anthropogenic factors could lead to potential environmental risk as indicated by the contamination degree and the Geo-accumulation index (Igeo) results of heavy metals. On the other hand, the maximum metal concentrations of Fe, Pb and Cd were found in Atriplex portulacoides, whereas Ni and Co were related to Halocnemum strobilaceum, respectively. On the basis of the BAF values, the studied plant species could be considered as hyperaccumulators for Fe, Pb, Cd and Co (BAF values >1) except Ni. Further observations should be considered to apply these halophyte species as remediators in different applied sectors.