Spatial and temporal characterization of water quality of the N'djili River in Kinshasa

Abstract

The overall objective of this study was to conduct a spatio-temporal characterization of the water quality of the N'djili River in Kinshasa through the evaluation of its physical, chemical and bacteriological parameters. Data was collected during the months of September and November 2019. The evaluation of physical parameters (pH, temperature (°C), conductivity (µS/cm), turbidity (ppm) and transparency (cm) of the water was carried out in situ. The chemical parameters (dissolved oxygen (mg/L), nitrates (mg/L), nitrites (mg/L), phosphates (mg/L), suspended solids (mg/L), oxidizable solids (mg/L), BOD5 (mg/L), COD (mg/L)) and bacteriological parameters were analyzed at the Central Laboratory located in the commune of Limete in Kinshasa. The results showed that the physical, chemical and bacteriological quality of the N'djili River water varies according to site and sampling period. In general, water of this river is more loaded during rainy periods and the Lukaya river basin, the urban drainage network and the houses in the catchment areas bring pollutants into this river. Microbiological analyses showed that the more the N'djili River crosses inhabited areas, the more it is overloaded with germs. The high density of total coliforms and Escherichia coli in the water of the N'djili River confirms the contamination of the water of this river by human and animal faecal matter.