Hydrogeochemical Characterisation and Quality of Groundwater for Drinking and Irrigation in the Rural Commune of Gouna, Zinder, Niger Region

The study area, the rural Commune of Gouna is located in the south of the department of Mirriah between latitudes 13°17' and 13°43' N and longitudes 9°08' and 9°19' E. From a hydrogeological point of view, the municipality is underlain by groundwater aquifers formed by formations of recent Korama sands and discontinuous formations of the Damagaram. These aquifers are much in demand for drinking water supply, animal watering and irrigation, which is booming in the commune. Because of their shallow aquifers are very sensitive to anthropogenic pollution. The aim of this study is to characterise the se aquifers from a hydrogeochemical and assess the suitability of these waters for human consumption and irrigation. Forthy (42) water samples from hand-dugwells and boreholes were analysed. The methodology applied involves conventional hydrochemical approaches the use of Piper diagrams and the correlation matrix, Principal Component Analysis and the water quality assement (SAR, USSL, %Na and Wilcox). Results showed that the water type is calcic bicarbonate (54.76%); calcic chloride (26.19%); magnesian (14.29%); sodium and potassium bicarbonate (4.76%) and sodium chloride facies Principal Component shows that mineralisation of the water in the study area is mainly controlled by the hydrolysis of silicate minerals due to the presence of CO2 in the soil, water-rock interactions due to residence time leaching from ferruginouss oils and human activities. Comparison of the analytical results with standards (2017) indicates that the majority of groundwater in the study area is fit for human consumption. However, some samples have NO3-, FeT, K+ and Ca2+exceeding the WHO standard. The percentage values for Na (%Na), SAR and the positioning of samples on the Wilcox indicate that the water is of excellent quality for irrigation.