Assessment of the health hazards associated with wastewater reuse: transmission of geohelminthic infections (Marrakech, Morocco)

Abstract

To address the problem of water scarcity, wastewater has long been used for agricultural purposes in Marrakech (Morocco) and its benefits have long been recognized. However, the benefits of urban wastewater reuse may be limited by its potential health hazards associated essentially to the danger of transmission of pathogenic organisms to human beings. The current study aimed to evaluate the risks associated with raw wastewater reuse for agricultural purposes, and the incidence of geohelminthic infections among the children of the wastewater spreading area of Marrakech as compared to a control group. Faecal samples from 610 individuals were examined for Ascaris spp. ova and Trichuris spp. ova (323 children for the exposed group and 287 for the control group). The study duration was two months and a half, and was carried out in the summer period. A questionnaire-interview with children and parents was used to collect data on possible demographic, hygiene and behavioural-contact factors such as gender, age, family size, source of water supply, parental occupation. The investigations resulted in the detection of Ascaris spp. ova in 43 samples indicating a point-prevalence of 13.3% in the exposed group versus 1.7% for the control group. Trichuris spp. ova was detected in 43 faecal samples indicating a point-prevalence of 13.3% in the exposed group, and 3.8% in the control group. The Chi-square test showed that the differences observed between the exposed and control group are statistically significant (p < 0.01). Males are more infected with ascariasis and trichuriasis than females and children of 2-8 years of age are heavily infected as compared to 9 - 14-year-old children. Based upon the findings of this study, it is concluded that wastewater reuse for agricultural purposes presents an increased risk of infection in the exposed group.