Multifaceted Contamination of Khoumane Wadi (Morocco): Coupling Physicochemical Degradation with Bacteriological and Parasitological Threats to Ecosystem and Public Health

Abstract

Khoumane Wadi, an important watercourse in the Moulay Idriss Zerhoun region, is undergoing marked environmental degradation driven by human activities. To evaluate the scale of this deterioration, a 1-year multidisciplinary assessment was carried out at six stations. The study examined physicochemical parameters, water quality index (WQI), organic pollution index (OPI), bacteriological indicators, and parasitics species following standardized procedures. The results revealed widespread and multifaceted pollution with significant spatiotemporal variations throughout the wadi. Physicochemical analyses demonstrated severe water quality deterioration, particularly at station S2, which exhibited exceptionally high contamination levels (maximum WQI: 3,469.60; maximum OPI: 173.63). This station was characterized by critical deoxygenation (0.7 mg/L), excessive organic load (BOD5: 670 mg/L), and intense nutrient pollution (NH4+: 23.7 mg/L; NO3−: 174.8 mg/L). Microbiological contamination consistently exceeded WHO standards across all stations, with total coliforms reaching a maximum concentration of 6,480 CFU/100 mL. Parasitological analysis revealed the widespread presence of six pathogenic species, with two reaching alarming levels: Giardia lamblia at 1,842 cysts/L and Fasciola hepatica at 1,075 eggs/L. Overall, the study demonstrates that contamination levels pose significant risks to both public health and the local ecosystem, highlighting the urgent need for improved monitoring and management of water discharges in Khoumane Wadi.