Compositions and mobility of major, δD, δ 18 O, trace, and REEs patterns in water sources at Benue River Basin-Cameroon: implications for recharge mechanisms, geo-environmental controls, and public health.

Autor: Fantong WY; Hydrological Research Centre, Institute of Geological and Mining Research (IRGM), Box 4110, Yaoundé, Cameroon. fantongy@gmail.com., Jokam Nenkam TLL; PRESS NO & SW, P.O. Box 169, Yaoundé, Cameroon., Nbendah P; PRESS NO & SW, P.O. Box 169, Yaoundé, Cameroon., Kimbi SB; Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8527, Japan., Fru EC; School of Earth and Ocean Sciences, Institute of Geochemistry and Geobiology, Cardiff University, Cardiff, Park Place, Wales, UK., Kamtchueng BT; Hydrological Research Centre, Institute of Geological and Mining Research (IRGM), Box 4110, Yaoundé, Cameroon., Takoundjou AF; Hydrological Research Centre, Institute of Geological and Mining Research (IRGM), Box 4110, Yaoundé, Cameroon., Tejiobou AR; Department of Geography, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon., Ngueutchoua G; Department of Earth Sciences, University of Yaoundé 1, P.O. Box 812, Yaoundé, Cameroon., Kringel R; PRESS NO & SW, P.O. Box 169, Yaoundé, Cameroon.; Federal Institute of Geoscience and Natural Resources (BGR), Hannover, Germany.
Jazyk: angličtina
Zdroj: Environmental geochemistry and health [Environ Geochem Health] 2020 Sep; Vol. 42 (9), pp. 2975-3013. Date of Electronic Publication: 2020 Feb 28.
DOI: 10.1007/s10653-020-00539-w
Abstrakt: Hydro-geochemical data are required for understanding of water quality, provenance, and chemical composition for the 2,117,700 km 2 Niger River Basin. This study presents hydro-geochemical 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 hydro-chemical signatures that vary from Ca + Mg - NO 3 in shallow wells to Na + K - HCO 3 in boreholes and surface waters, with undesirable concentrations of fluoride identified as major source of fluorosis in the local population. Our results further indicate non-isochemical dissolution of local rocks by water, with springs, wells and borehole waters exhibiting surface water-gaining, 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, Mo, Na, K, Rb, Ca, Li, Sr, Ba, Zn, Pb) are more mobile and enriched in the aqueous phase, whereas transition metals display an intermediate behavior. Trace elements vary in the order of Ba > Sr > Zn > Li > V > Cu > Ni > Co > As > Cr > Sc > Ti > Be > Pb > Cd, with potentially harmful elements such as Cd, As, and Pb mobilized in acidic media attaining near-undesirable levels in populated localities. With the exception of Y, REEs distribution in groundwater in the order of Eu > Sm > Ce > Nd > La > Gd > Pr > Dy > Er > Yb > Ho > Tb > Tm differs slightly with surface water composition. Post-Archean Average Australian Shale-normalized REEs patterns ranging from 1.08 to 199 point to the dissolution of silicates as key sources of trace elements to groundwater, coupled to deposition by eolian dust.
Databáze: MEDLINE
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