TITLE:
Hydrochemical Characterisation and Assessment of the Level of Contamination of Groundwater Collected by Private Waterworks in the Town of Moundou in the South of Chad
AUTHORS:
Prosper Doumtoudjinodji, Elegbede Manou Bernadin, Jean Claude Doumnang Mbaigane, Nguérassem Djoueingue, Urbain Agnichola, Akilou Socohou Amadou
KEYWORDS:
Drinking Water, Groundwater, Chemical Pollution, Moundou Chad
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.12 No.1,
January
12,
2024
ABSTRACT: Groundwater is the main source of drinking water for large cities in most
African countries. In Moundou, for example, the conventional groundwater supply
system is failing. To compensate for this state failure, the population is
building boreholes and wells, most of which tap the surface water table,
generally referred to as the “water table”. The aim
of this study is to characterize these waters in order to assess their level of
contamination and, by extension, the degree of pollution of the water table. Major
elements such as: Chloride (Cl-), Sulfate (SO42-), Nitrate (NO3-), Calcium (Ca2+), magnesium (Mg2+),
sodium (Na+) and potassium (K+) were analysed by Liquid
Chromatography and the Bicarbonate ion (HCO3-) was determined by the titrimetric method. The
methodology applied is based on a combination of hydrochemical techniques and statistical
analysis (PCA and CHA). A sampling campaign was carried out during high-water
periods. The results of the physico-chemical analyses show mineralization ranging
from 7.29 to 3670 μS/cm, with an average of 487.44 μS/cm. The groundwater
studied is generally acidic, with a pH ranging from 3.26 to 6.41. Based on
their anions, they are classified into four main hydrochemical facies: chloride
and sulphate facies, calcium and magnesium facies, sodium and potassium facies
and bicarbonate facies. The various correlations between major ions and
statistical analyses have enabled us to identify three hydrogeochemical
processes involved in water mineralization. The
dominant process is silicate hydrolysis, followed by cation exchange, then anthropogenic input, which influences mineralization by polluting the water.