Click here to view linked References Hydrogeochemical data are required for understanding of water quality, provenance and chemical composition for the 2117700 km 2 Niger River Basin. This study presents hydrogeochemical analysis of the Benue River Basin, a major tributary of the Niger River. The distribution of, major ions, Si, δD and δ 18 O, Trace and Rare Earth Elements (TE and REEs, respectively) composition in 86 random water samples, revealed mixing of, groundwater with surface water to recharge shallow aquifers by July and September rains. Equilibration of groundwater with kaolinite, and montmorillonites by, incongruent dissolution imprints hydrochemical signatures that vary from Ca+Mg-NO3 in shallow wells to Na+K-HCO3 in boreholes and surface waters, with undesirable concentrations of fluoride identified as major source of fluorosis in the local population. Our results further indicate nonisochemical dissolution of local rocks by water, with springs, wells and borehole waters exhibiting surface watergaining, weakest water-rock interaction, and strongest water-rock interaction processes, respectively. Poorly mobile elements (Al, Th and Fe) are preferentially retained in the solid residue of incongruent dissolution, while alkalis, alkaline earth and oxo-anion-forming elements (U,

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In this study, we investigated the distribution and the principal sources of macronutrients (N, P, K, S) in groundwater in agro-pastorally dominated North Cameroon. Graphical methods and multivariate statistics were used to understand the impact of land use and regional geology on nutrient concentrations (K+, NO3−, SO42−, PO43−). Groundwater was acidic (median pH 6.8) and more mineralized (EC range = 35–2500 µS/cm, median = 376 µS/cm) than surface water (EC range = 50–222 µS/cm, median = 81 µS/cm). The median concentration of nutrients was (in mg/L) in the order NO3− (41.3) > SO42− (7.7) > K+ (5.2) > PO43− (0.1) in groundwater and rather K+ (3.3) > NO3− (0.3) > SO42− (0.2) > PO43− (0.2) in surface water. Using hierarchical cluster analysis and Schoeller diagram, we identified three distinct water quality groups. Group I, which contained cluster 1 and 2 were generally less mineralized and characterised as Na + K − HCO3 water type found in the urban area such as Garoua and Lagdo. Group II, containing cluster 3 was much higher mineralized and characterised as the Na + K − HCO3 water type with elevated nitrate. The occurrence of these groups is linked to the outcrops of cretaceous terrestrial sediments of the Garoua basin. Group III, which contained cluster 4 were heavily mineralized and characterised as the Ca + Mg − NO3 water type. The occurrence was controlled by the outcrop of the crystalline Proterozoic basement. The nitrate median (41 mg/L) found in groundwater demonstrates the influence exerted by anthropogenic activities. Management strategies are required for the whole study area to limit further deterioration of groundwater resources in the wake of the planned expansion of agricultural productivity in the North Region of Cameroon.