Bioavailability and Assessment of Metal Contamination in Surface Sediments of Rades-Hamam Lif Coast, around Meliane River (Gulf of Tunis, Tunisia, Mediterranean Sea)

Rim Ben Amor,Myriam Abidi,Moncef Gueddari,Lasaad Chouba,Asma Yahyaoui

doi:10.1155/2019/4284987

Abstract

The total concentration and the speciation of heavy metals (Pb, Cd, Cu, Zn, Ni, and Cr) in surface sediments of Rades-Hamam Lif coast were determined, with particular focus on the effect that urban and industrial waste in the Meliane river has on the estuary and coastal surface sediments of the Rades-Hamam Lif coast, off the Mediterranean Sea. Several geochemical indices were applied to assess the risk of contamination and the environmental risks of heavy metals on surface sediments. The total concentrations of these heavy metals are influenced by runoff, industrial, and urban wastewater. The Cd, Pb, Zn, and Ni are affected by anthropogenic sources, especially at the mouth of the Meliane river. The sequential extraction of Cd was presented dominantly in the exchangeable fraction and thus the high potential bioavailability. In contrast, Cr and Cu were mostly bound to the residual fraction indicating their low toxicity and bioavailability. The order of migration and transformation sequence was Cd > Pb > Ni > Zn > Cr > Cu, and the degree of pollution was Cd > Pb > Ni > Zn > Cr > Cu.

Highlights

Coastal sediments are generally exposed to heavy metal pollution from urban and industrial activities, especially in river mouth [1, 2]
Grain size distribution and TOC concentration were determined to obtain the general characteristics of the surface sediment samples from the Rades-Hamam Lif coast. e studied surface sediments were characterized by heterogeneous concentration of TOC. at constituted 0.75–3.02% of the dry weight the sediment (Table 4)
The elements that have high correlation in sediments can have the same origins, similar behaviors during the different phases of transformation between the dissolved and particulate phases [3, 31]. erefore, Pb, Cd, Cr, Cu, Ni, and Zn may have a common source which is most probably the urban and the industrial wastewater discharged into the Meliane river

Summary

Introduction

Coastal sediments are generally exposed to heavy metal pollution from urban and industrial activities, especially in river mouth [1, 2]. Trace metals in marine sediments may have natural and anthropogenic sources such as sewage discharges and urban and industrial effluents [3, 4]. Several geochemical indexes can be used to evaluate the anthropogenic impact of heavy metals in sediments, such as geoaccumulation index, contamination factor, and pollution load index [12]. Heavy metal contamination in a marine coastal environment is associated with pollution sources in estuaries and adjacent rivers. The main source of anthropogenic metals in coastal areas is of terrestrial origin, i.e., mining, industrial, as well as urban development, and other human practices near rivers [13, 14]

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