Impact of Autonomous Sanitation Practices on Groundwater Quality: Case of Peripheral Neighborhoods of the 7th Arrondissement of the City of N'Djamena, Chad

This study assesses the impact of on-site sanitation practices on the bacteriological quality of borehole water in the outlying neighborhoods of the 7th arrondissement of N'Djamena. To this end, sixteen (16) water samples were collected from 16 boreholes for physical and microbiological analyses, combined with piezometric sampling. The results show the presence of Escherichia coli in five of the 16 boreholes. Total coliforms and total aerobic bacteria were detected in all sampled boreholes. Fecal enterococci were found in only one borehole. The presence of these microorganisms, indicators of fecal contamination, in the samples reveals the link between the sampled water points and the wastewater treatment facilities. The piezometric map identified three areas of depression, two areas of high groundwater, and several low piezometric levels.