Assessment of sediments contamination by potential toxic elements, in relationships with the physicochemical characteristics of Moroccan Oued Fez river

Abstract

The Oued Fez river has long been significantly impacted by various sources of pollution, including industrial activities. However, there is limited available data concerning the presence of potentially harmful toxic elements that could affect human health in this area. The primary aim of this study was to evaluate the spatial and temporal distribution of nine Potential Toxic Elements (PTEs) Aluminum (Al), Cadmium (Cd), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), Nickel (Ni), Arsenic (As), and Zinc (Zn) in the sediment of the Oued Fez river. In both February and August, we collected four sediment samples at six different locations along the Oued Fez. To ensure sample consistency at each station, we mixed the sediment samples, dried them, and finely ground them into a powder. We then used acid etching to dissolve the samples, and the concentrations of these PTEs were determined using the ICP-AES method. The findings revealed that heavy metal concentrations were higher in February compared to August, with a gradual increase observed from upstream to downstream areas of the river. Specifically, in February, site six (S6) exhibited the highest values for Fe at 27,749.6 mg.kg−1 and Al at 13,967.2 mg.kg−1. Additionally, the PCA analysis and assessment of sediment contamination indicated that the sediment was more contaminated with Fe, Al, and Zn, especially at upstream stations (S5 and S6). This contamination can be attributed to their proximity to the industrial area. These results clearly demonstrate that anthropogenic factors, particularly industrial activities, are contributing to increased sediment contamination by PTEs. This contamination not only jeopardizes the environmental integrity of this site but also poses a significant threat to human health.