Physico-chemical Characterization and Assessment of the Risk of Pollution: A Case of Wastewater Generated by the Regional Hospital and the Central Prison of the City of Ngaoundere, Cameroon

Among the public spaces with high human user traffic- schools, hospitals and prisons generate the most volumes of wastewater in developing countries. In addition, when this wastewater is discharged into natural environments without treatment, it can lead to disastrous pollution. The aim of this study is to analyze the physico-chemical parameters of the wastewater of the central prison and the regional hospital in the city of Ngaoundere (Cameroon) and to assess their pollution potential. To achieve this, physical-chemical parameters (temperature; pH; electrical conductivity, total suspended solid; COD, BOD5; heavy metal content) of water from a control site and wastewater from the regional hospital and central prison were measured and compared to current standards. In order to better assess the risk of pollution, a wastewater quality index (WWQI) and a heavy metal pollution index (HPI) were calculated. It shows that for all physico-chemical parameters studied, the values are above the norm except temperature and pH. With a WWQI of 172.81 from prison’s wastewater and of 176.03 from hospital’s wastewater, these wastewaters have values above 100 and are therefore highly polluted. The heavy metal pollution index is 37.89 for control water, 183.10 for prison wastewater and 121.14 for hospital wastewater, respectively. Cadmium and especially lead contribute to increasing the heavy metal pollution index in wastewater. Remediation of these waters should therefore focus on these two heavy metals. The above-standard concentrations of some parameters and pollutants as well as the high wastewater quality index and heavy metal index suggest that the discharge of this wastewater into the natural environment without treatment or its direct use as fertilizers constitutes a potential source of pollution of the soil and surrounding vegetation and beyond a threat to human health if these pollutants enter the human food chain.