Monitoring Water Pollution Levels in Wadi Hanifa, Riyadh, Saudi Arabia and its Public Health Implications

This study was performed to evaluate the levels of metals in the fish caught from Wadi Hanifa's main basin over four seasons, determine the potential fitness of the fish for human consumption, and evaluate the overall water quality after enforcement of local standards. The physical and chemical parameters from a total of 192 water samples were tested using standard methods. Additionally, a total of 48 fish samples were analyzed for heavy metal concentrations. Mean values for basic water quality parameters of COD, PO₄^-3, NH₃^--N, and NO₃^--N exceeded Saudi standards in all seasons. Mean metal concentrations in water were consistently at their highest concentrations in samples collected during the summer, and the lowest in samples collected during the winter. Mean metal concentrations in fish muscle tissue exceeded Saudi standards for As and Cd, and United Nations FAO standards for Cr, Ni, Zn, Fe and Mn. Statistical analysis showed highly significant positive correlations between metal concentrations in water and metal concentrations in fish muscle for As-Fe, Pb-Cr, Pb-Ni, Cr-Cu, and Cu-Fe. This study highlights the urgent need for monitoring and controlling wastewater discharge in Wadi Hanifa to ensure public safety.