Distribution and assessment of trace metal contamination in the surface sediments of the Meliane River and the Coast of the Gulf of Tunis (Tunisia, Mediterranean Sea)

Abstract

The Meliane River, the second longest and most important river in Tunisia, is one of the major rivers that flow into the Gulf of Tunis. However, it is known by its significant discharges of urban and industrial activities that have seriously affected the quality of the aquatic ecosystem. The highest amounts of Cadmium (Cd), Copper (Cu), Lead (Pb), Zinc (Zn), Nickel (Ni), Chromium (Cr) and Manganese (Mn) in the surface sediments of the Meliane River indicate that the downstream part is the most polluted area. The chemical speciation shows that the majority of the trace metals are bound to a reducible fraction (Zn, Mn, Cr and Ni) and the Pb and Cu are bound to the oxidizable fraction. The Cd is linked to the exchangeable fraction, which indicates its high mobility and toxicity. Both the contamination and enrichment factors values of some trace metals are elevated in the downstream part of the Meliane River. The percentage of the risk assessment code in Cd is 59.8%, which presents a very high environmental risk. Therefore, the spatial distribution of trace elements in the surface sediments is characterized by its high concentration of metals in the downstream part of the Meliane River. These concentrations decrease as a function of change in the physicochemical parameters from the freshwater-saltwater mixing zone to marine stations.

Microplastic-sorbed persistent organic pollutants in coastal Mediterranean Sea areas of Tunisia

“…39 Ezzahra beach is affected by different types of anthropogenic pressure: the proximity of the industrial complex of Tunis bay (chemical and metallurgic industries, ports, food and paper factories), the Rades sewage treatment plant, the mouth of Oued Meliane (having a solid discharge ow of around 20 400 tons per year) and the Ezzahra city. 40,41 All of the four beaches are affected by a high touristic pressure during summer. Furthermore, they are open to the Mediterranean ea which is considered among the most affected seas by MPs pollution (receives 5 to 10% of the global plastic mass).…”

Trace Element Correlations in Mussels and Sediments on the Moroccan Mediterranean Coast

“…This research can lead to the development of more stringent environmental regulations and the implementation of targeted remediation programs aimed at reducing the emission of dangerous pollutants. It also informs the development of community health advisories and helps in shaping sustainable practices for industries that are pivotal to the economy but are also potential sources of marine pollution (El Ouaty, 2022, Yahyaoui, 2022. In essence, the study of trace metals in such contexts serves a dual purpose: advancing scientific understanding of environmental contaminant dynamics and fostering policy frameworks that prioritize ecosystem health and human well-being (Ghribi, 2020).…”