A longitudinal study was conducted in 2020 and 2022 to evaluate trace element contamination in fluvial sediments of the El Harrach river within the catchment area, a semi-arid Mediterranean watershed, increasingly subject to anthropogenic pressures that affect Algiers Bay and the Mediterranean Sea. Forty-eight fluvial sediment samples were collected from eight sampling stations under contrasting hydrological conditions. Trace element concentrations were measured using X-ray fluorescence spectroscopy (XRFS), and geochemical indices were applied to assess the contamination level. The result revealed an overall moderate contamination, with significant enrichment of Cd, Co, Cu, Ni and Pb at downstream sampling stations, while As, Cr, Mo and Zn showed a low level of enrichment. Cd emerged as the most bioavailable element. PERMANOVA and PCA underscored the significant influence of seasonality and spatial variability, linking Ni with Ca, and associating As and Cr with iron/manganese oxides, suggesting predominantly natural geochemical controls. In contrast, Cd, Co, Cu, Zn and Pb were more strongly related to anthropogenic sources such as industrial, urban and agricultural activities. These findings eventually provide essential baseline data for managing sediment quality and preserving ecological integrity in Algiers Bay.