Hydrochemical and Bacteriological Characterization of Drinking Water in N'Djamena: A Case Study of the 2<sup>nd</sup> District

Access to drinking water is a major concern in the locality of least developing countries. Population growth and the demands of modern life require an increase in water production in both quantity and quality. This study aims to determine the physicochemical and microbiological quality of water from boreholes intended for human consumption in the 2<sup>nd</sup> district of N'Djamena, Chad. The methods used to solve the problem are based on physicochemical and microbiological analyses, the Piper diagram interpretation, and multivariate statistical analysis to determine the quality and classification of the water. The results show that the water has low mineralization with a Total Dissolved Solid (TDS) concentration of 141.2 ± 26.61 mg/L and an average electrical conductivity of 282.4 ± 53.58 µS/cm. And then, determination of the facies of the waters studied shows that they are of the calcium-magnesium bicarbonate type. The highest concentrations are those of Ca<sup>2+</sup> (38.3 ± 7.79 mg/L) and HCO<sub>3</sub><sup>-</sup> (189.76 ± 17.36 mg/L), and the lowest are K<sup>+</sup> (3.06 ± 0.63 mg/L) and NO<sub>3</sub><sup>-</sup> (5.76 ±9.43 mg/L). The water contains fecal coliforms such as Escherichia coli, total coliforms, and Total Aerobic Mesophilic Flora. Due to the presence of these pathogenic germs, this water requires prior treatment before being used for human consumption.