A systematic review of potential toxic elements contamination in coastal and freshwater sediments from Algeria over the past two decades

The increase in concentrations of potential toxic elements resulting from human activities has raised concerns about their impact on human health and ecosystems. A total of 41 research articles were reviewed, and the contamination status of eleven trace elements (Cd, Co, Cu, Pb, Cr, Fe, Zn, Mn, Ni, Hg, and As) in freshwater and marine sediments was evaluated using available published data from 2000 to 2021. Furthermore, the geo-accumulation index (I_geo), the integrated pollution index (IPI), and the potential ecological risk index were calculated.

Metal concentrations in Algerian freshwater and marine sediments were found to vary among 62 regions, linked to factors such as the use of leaded gasoline, mining sites, the use of pesticides and chemical fertilizers, fishing harbors, naval construction, urban and industrial wastes, and the absence of wastewater treatment. The I_geo indices showed that Cd, Pb, and Zn are the significant pollutants, with probabilities of Algerian sediment being higher than 0 at 91.31 %, 89.66 %, and 65.39 %, respectively, in freshwater and 42.86 %, 34.38 %, and 34.38 %, respectively, in coastal sediment. The IPI indicated that values were higher than 1 in 85.71 % of studied rivers and 31.25 % of coastal study areas, suggesting that freshwater sediments in Algerian are more highly polluted compared to coastal sediments.

It is evident that continuous monitoring and management are essential to mitigate significant contamination resulting from industrial complexes, agricultural practices, and commercial activities in areas adjacent to rivers and marine environments.