Study of the Impact of Irrigation with Wastewater Through the Evaluation of Intestinal Parasite Load in the Case of Ouad Rha in Ouazzane, a Northern Moroccan City

Facing the challenges of climate change and the scarcity of clean irrigation water, the use of wastewater for irrigation is experiencing significant growth. This study focuses on the impact of irrigation with wastewater on the prevalence of intestinal parasites, specifically in the case of Oued Rha in Ouezzane, Morocco. By assessing the parasitic load in wastewater, analyzing spatiotemporal variations in types and quantities of parasites, and examining the contamination of vegetable crops, several key findings have been revealed. In total, 33 species of vegetable crops, distributed among 11 families, were identified, with a predominance of Cucurbitaceae, Solanaceae, Apiaceae, Asteraceae, and Brassicaceae. The edible parts most affected by parasitic contamination, in decreasing order, are leaves, underground parts, and fruits. Regarding fruit trees, 14 species belonging to 7 families were recorded, with a predominance of Rosaceae. Parasitological analysis of wastewater used for irrigation revealed the presence of 10 taxa of intestinal parasites, the most common being protozoan cysts (Entamoeba sp., Endolimax nana, Giardia intestinalis) and helminth eggs (Ankylostoma duodenale, Ascaris lumbricoides, Enterobius vermicularis, Trichuris trichiura, Strongyloides stercoralis, Hymenolepis nana, Taenia saginata). Self-purification rates for protozoan cysts range from 77.21% to 95.87%, while for helminth eggs, they vary from 81.44% to 95.87%. Parasitic loads decrease over a distance of 3 km along Oued Rha, with the highest parasite load recorded around 11 AM. These intestinal parasites pose a health risk, potentially leading to various infections in consumers. Ultimately, the urban wastewater from Oued Rha does not meet WHO and Moroccan standards for parasitological quality, posing a significant risk to the health of consumers of vegetable crops irrigated with this wastewater. Therefore, the use of this wastewater for irrigating vegetable crops should be discouraged. In summary, the parasitic load of Oued Rha wastewater reflects the parasitic characteristics of the population of the city of Ouezzane, highlighting the potential impact on public health.