Toxic Potential, Health and Environmental Risks of Pollutants Detected in the Waters of Oued Larbaa, Taza, Northern Morocco

The Moroccan Inaouen River suffers from significant pollution caused by various human activities. This study aimed to evaluate the concentrations of potentially toxic elements (PTEs) in surface and groundwater from the tributaries of the Inaouen River near Taza, Morocco. The eventual pollution from the public dump of Taza City was investigated using eight sites and fifteen parameters: Temperature, Electrical Conductivity, pH, and twelve PTEs were used to assess the Heavy Metal Pollution Index (HPI), Hazard Quotient (HQ), Hazard Index (HI), and cancer index (CI). Results showed that Al, As, Cd, and Pb concentrations exceeded WHO limits across all sites. Mn, Fe, Ba, and Ni exceeded limits at O2, O3, O4, and O6, closest to the public dump and in the direction of water flow. In contrast, Co, Cr, Cu, and Zn remained within permissible limits. In addition, HPI exceeded permissible limit across all sites. HQ and HI associated with using contaminated water indicated that the HI for Zn, Cu, Ba, Ni, As, Pb, Cr, Mn, Co, and Cd were greater than 1, signifying a potential risk for users of this water. Finally, the CI values of the studied elements allowed them to be ranked in ascending order of toxicity, from least to most toxic: Pb>As>Cr>Cd>Ni. The present results showed that water pollution by PTEs is more significant in surface waters that receive the leachate from the public dump and is not negligible in groundwater, which can have serious repercussions on human health and living organisms, necessitating urgent remediation efforts.