Agriculture and livestock are the main socio-economic activities of the population of the Zinder region (Niger). However, these activities have negative impacts on groundwater quality, which is the main source of water supply for this population. In this work, the physicochemical quality of the waters of the Socle of the Zinder region was studied during the rainy and dry seasons. Twenty-four samples were the subject of a physico-chemical analysis. The data obtained were processed by the hydrochemical method by the Diagram software and the principal component analysis by the XLSTAT software. Of the waters analyzed, 83% have normal pH values (6.5 - 8.5) and 17% acid pH <6.5 during both seasons. The nitrate levels of Yekoua (62.04 and 63.36 mg.L-1), Dan Ladi (123.64 and 146.96 mg.L-1), Bourbourwa (64.65 and 80.08 mg.L -1) and Kazoé (130.68 and 124.52 mg.L-1) and fluoride of Kazoé (1.5 mg.L-1), Midik (1.6 mg.L-1) and Bourbourwa (2.98 mg.L-1) during both seasons are abnormal. Four facies characterize the analyzed waters, with a predominance of bicarbonated calci-magnesian(42%) during the rainy season, calci-magnesian bicarbonate (41.7%) and calci-magnesium chloride (41.7%) during the dry season. The residence time by hydrolysis and alteration of silicate rocks and the pluviolessivage of soils are the main mechanisms that govern the mineralization of these waters. These grades, call for remediation treatments. Clays could be promoters for this treatment because they are very available and less expensive.

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In recent years, sachet water known as "pure water" has gained the confidence of the Nigerien public because of its low price, availability, convenience, and quality perception by consumers. This study highlights the impact of storage on the quality of pure water sold in Niamey. Thus, eleven of the twelve analyzed physicochemical parameters have been monitored during six weeks of "pure water" storage in the sun and at laboratory ambient temperature. From the results obtained, the physicochemical parameters are in norms except the turbidity and the residual chlorine. On the Bacteriological plan, the total germs, the salmonellae, the fecal streptococci and the Escherichia coli have been identified. In addition, the monitoring of the evolution of the parameters analyzed during six weeks of storage revealed a change of the organoleptic quality that appears in the fourth week and a development of Escherichia Coli for the "pure water" exposed in the sun. This study showed, on the one hand, that these "pure water" would be unfit to the human consumption and on the other hand, their storage for a prolonged period and a high temperature affects their qualities. Les eaux conditionnées en sachet plastique, communément appelées "pure water", ont depuis quelques années, gagné la confiance du public nigérien en raison de leur faible prix, leur disponibilité, la commodité, et de la perception de qualité par les consommateurs. Ce travail étudie l’impact du stockage sur la qualité des "pure water" vendues à Niamey. Ainsi, onze parmi les douze paramètres physico-chimiques analysés ont été suivis pendant six semaines de stockage des "pure water" au soleil et à la température ambiante de laboratoire. A l’issue des résultats obtenus, les paramètres physico-chimiques sont dans les normes hormis la turbidité et le chlore résiduel. Sur le plan bactériologique, les germes totaux, les salmonelles, les streptocoques fécaux et les Escherichia colis ont été identifiés. Par ailleurs, le suivi de l’évolution des paramètres analysés pendant six semaines de stockage a révélé une altération de la qualité organoleptique qui se manifeste à la quatrième semaine et un développement des Escherichia colis pour les "pure water" exposées au soleil. Cette étude a montré, d’une part, que ces "pure water" seraient impropres à la consommation humaine et d’autre part, leur stockage pendant une période prolongée et une température élevée affecte leurs qualités.