Mobility and risk assessment of heavy metals by sequential extraction in coastal sediment south Mediterranean Sea, Egypt
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The chemical speciation of metals (Cd, Zn, Cu, and Fe) for coastal marine sediment samples collected from ten locations in the Western Harbour (main harbour) in Egypt and has been studied in two surveys which were determined using the four-step sequential extraction procedure. A sequential extraction technique was used to quantify exchangeable, oxides (reducible), organic/sulphidic, and acid-soluble (residual) fraction. It was noticed that Cd and Zn have the highest capability to be released from the sediment, more mobile and bioavailable, by the simple ion exchange mechanism in the W.H than Cu and Fe which were present at higher percentages in the acid-soluble fraction, meaning that these two metals were strongly bound to the sediments. Considering the percentage of metals extracted in the most labile fractions (F1 + F2 + F3), the order of mobility (from most to least bioavailable) was: Cd (94%) > Zn (64%) > Cu (22%) > Fe (3.5%). Risk assessment code (RAC) analysis indicated that the sediments show no risk for Fe and a low risk for Cu and low-to-medium risks for Zn and medium-to-high risks for Cd with RAC values greater than 11% and 30%, respectively, indicating a substantial risk of metal mobilization from sediments across the entire study region.
KeywordsSediment Metals Bioavailability Risk assessment Western Harbour Egypt
The authors would like to thank the colleagues in the National Institute of Oceanography and Fisheries for their help and support during the collecting the samples from the Western Harbour. In addition, the thanks to the anonymous reviewer who constructive comments significantly improved this paper.
- 1.M.A.M. Abdallah, Trace metal behavior in Mediterranean-climate coastal bay: El-Mex Bay, Egypt and its coastal environment. Glob J Environ Res 2(1), 23–29 (2008)Google Scholar
- 2.M.A.M. Abdallah, N.B. El Sayed, M.A. Saad, Distribution and enrichment evaluation of heavy metals in El-Mex Bay using normalization models. Fresenius Environ. Bull. 16(7), 710–719 (2007)Google Scholar
- 7.M.K. El-Sayed, S.K. El-Wakeel, A.E. Refaat, Factor analysis of sediments in the Alexandria western Harbor, Egypt. Oceanol. Acta 11, 1–11 (1988)Google Scholar
- 12.A. McGrath, P.R. Paquin, D.M. Di Toro, Use of the SEM and AVS approach in predicting metal toxicity in sediments. Fact Sheet Environ. Risk Assess. 10, 1–6 (2002)Google Scholar
- 16.G. Perin, L. Craboledda, M. Lucchese, R. Cirillo, L. Dotta, M.L. Zanette, A.A. Orio, Heavy metal speciation in the sediments of Northern Adriatic sea—a new approach for environmental toxicity determination, in Heavy Metal in the Environment, vol 2, ed. by T.D. Lekkas (1985), pp. 454–466Google Scholar
- 24.UN ESCAP, Commercial development of regional ports as logistics centres, transport and tourism division (TTD), in ST/ESCAP/2194, (United Nations, New York, 2002)Google Scholar