Compositions and mobility of major, δD, δ18O, trace, and REEs patterns in water sources at Benue River Basin—Cameroon: implications for recharge mechanisms, geo-environmental controls, and public health

Abstract

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,

Hydrogeochemistry of low agricultural soil yield in Sahelian and sub-tropical watersheds, Northern Cameroon

“…Al has a remarkable immobility, being retained in the products of incongruent dissolution as kaolinite and gibbsite. Contrary to the results in the Benue River Basin (Fantong et al, 2020), Mo, Cs and Sn are among the least mobile elements in the TBIW and the SDLSW.…”

“…4). Such patterns have been previously linked to the dissolution of plagioclase in the Benue River Basin of Northern Cameroon within which the SDLSW is situated (Fantong et al, 2020). Moreover, most of the shallow groundwater samples in SDLSW (Fig.…”

“…Etna in Sicily (Aiuppa et al, 2000), Mt. Vesuvius volcanic aquifer in Italy (Aiuppa et al, 2005), and sandstone terrain in Benue River Basin-Cameroon (Fantong et al, 2020). It was aso applied to calculate the relative mobility of elements for 5 samples from the TBIW and 5 samples from the SDLSW.…”

“…Integrated ecosystem management approaches on watershed have been proposed to evaluate the environmental impacts of human activities for temperate zones (Drever and Clow, 1995;Moldan and Cerny, 1994), but very rarely for the tropics (Bruijnzeel, 1990;Thomas, 1994;White and Blum, 1995), and Sahelian zones (Fantong et al, 2020). This management approach has been successfully applied to small hydrologic and topographically well-defined watersheds covering tens to thousands of hectares (e.g., Paces, 1983;Siegel and Pfannkuch, 1984;White et al, 1999).…”

“…Etinde in Cameroon (Etame et al, 2009); solute generation during silicate weathering in Japan (Vuai and Tokuyama, 2007); mobility and fluxes of elements during basalt weathering at Mt. Etna, Italy (Aiuppa et al, 2000); trace metal modelling of groundwater-gasrock interaction in a volcanic aquifer (Aiuppa et al, 2005); weathering rates of granitoids in humid tropical watersheds (Braun et al, 2005); chemical alteration and resulting clay minerals formed when fresh rocks are weathered (Andrews et al, 2004); implications of water-rock interaction on the failure of the Lake Nyos natural dam (Fantong et al, 2015); compositions and mobility of elements in the Benue River Basin in Cameroon (Fantong et al, 2020); quantification of elemental fluxes behaviour of chemical element fractionation during silicate rock weathering processes (White and Brantley, 1995); enrichment and depletion of elements in altered rocks within hydrochemical systems (Brimhall and Dietrich, 1987); rare earth elements variation in agricultural fields from eroded granitic hilly lands in southern China (Chen et al, 2019); bioaccumulation and translocation of rare earth elements (REEs) in two forage legumes grown in soils treated with coal fly ash (He et al, 2019); geochemistry and recharge mechanisms of groundwater from the Garoua sandstone aquifer in north Cameroon (Njitchoua et al, 1997); and integrated and sustainable management of shared aquifer systems and basins of the Sahel region (Huneau et al, 2017). These references discuss chemical weathering of bedrock minerals contribution to the abundance and availability of nutrients in soil horizons, which in turn determines crop yields (Dehnavi et al, 2011).…”