Trace Elements in Sediments and Mussels - Spatial Distribution, Chemical Partitioning, and Risk Assessment

Abstract

Sediment samples were collected from 30 different locations in Abu Qir Bay (Mediterranean Sea), East Alexandria, Egypt and analyzed for trace elements. The highest concentrations of most of the elements were observed in the nearshore stations in the vicinity of the major anthropogenic activities as industrial settlements, wastewater discharges, and agricultural drainage. In addition, mussel samples of Mactra corallina and Tapes decussata were collected corresponding to the sediment samples. Concentrations of As, Cd, Cr, Mn, and Zn in the mussel tissues were higher than concentrations in sediments, thus indicating their relatively high bioavailability. Sequential extraction procedure was performed on selected sediment samples. Significant correlations were observed between the concentrations of Cu, Mn, Pb, and Zn in the exchangeable fraction of the sediments and the corresponding tissues of M. corallina. The output of the risk assessment applied on the sediments revealed that adverse ecological effects to benthic species could occur and that a higher level of risk is expected from the exposure to Cd, Cr, Hg, and Zn. No adverse carcinogenic or non-carcinogenic human health effects are expected from the consumption of the two mussel species from Abu Qir Bay.The present study shows that both mussel species Mactra corallina and Tapes decussata could be good bioindicators for the evaluation of the environmental quality. However, only M. corallina showed high significant correlations to the sediment concentration presumably as T. decussata does not live in direct contact with bottom sediments. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.