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. ![]() 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. 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. 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. 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. The distribution of major ions, Si, δD, and δ 18O, 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. This study presents hydro-geochemical analysis of the Benue River Basin, a major tributary of the Niger River. ![]() This extremely encouraging result led to the design of an online NMR relaxometer for oil/water stream measurements under the conditions encountered in the production of heavy oil and bitumen.Hydro-geochemical data are required for understanding of water quality, provenance, and chemical composition for the 2,117,700 km 2 Niger River Basin. The technology was tested with both artificially and naturally occurring emulsified streams with accuracy better than 96﹪. The method was proved to be at least as good as conventional extraction methods (i.e., Dean-Stark). Low field NMR relaxometry was successfully tested as a tool for accurately measuring the oil and water content of such streams with and without emulsions present in the samples. Conventional methods are also not reliable when there are solids flowing in the stream. Conventional flow measuring devices are capable of measuring oil and water streams when they are segregated, but they fail when oil-in-water or water-in-oil emulsions form. ![]() ![]() This is also true in non-thermal recovery methods whenever oil and water are coproduced, but to a lower degree of severity. During production operations in heavy oil and bitumen formations where thermal recovery methods are applied, the fluids produced are often in the form of emulsions.
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