Chemical speciation and complexation modeling of trace and rare earth elements in groundwater of Oban Massif and Mamfe mMbayment southeastern Nigeria

Abstract

Chemical speciation was carried out on trace and rare earth elements on trace and rare earth elements data on water samples in Oban Massif and Mamfe Mbayment southeastern Nigeria. Product moment correlation showed significant correlation at r>0.7 between REEs Pr and Nd, Pr and Lu, Sm and Nd, Sm and Pr, Tb and Nd, Tm and Tb, and Yb and Nd. Speciation modeling result showed that free metal ionic species dominated boreholes and spring water samples. The predominant trace metal complex is the OH-ligand. Trace elements mineral saturation indexes in boreholes at oversaturation (S>1) predicted more mineral species than equilibrium saturation (S=0). Rare earth elements mineral oversaturation (S>1) in boreholes predicted least mineral species. Undersaturation (S<1) predicted highest range of rare earth elements minerals. Springs and streams at S>1, predicted more mineral range than equilibrium (S=O) while mineral prediction at S<1 were the highest. Rare earth elements are precipitated at undersaturated condition in the study area.

Re-examination of Hydrochemistry and Groundwater Potentials of Cross River and Imo-Kwa-Ibo Intersecting Tropical Basins of SouthSouth Nigeria

“…The longer tributaries which include the Onwu, Konshisha, and Aboine rises from the Enugu escarpment [44] . The River Calabar which is smaller arises from the Oban Massif in the east of the basin [45][46][47][48] . In terms of topography, the CRB is gently sloping, the surface rises at a low gradient from less than 200 meters above sea level, in the west and the southwest, to the uppermost points above 350 meters in the south-eastern parts, at the Oban hills and the northeast, at the Boji hills [44] .…”

“…The dominant carbonate mineral in most marls is calcite, but other carbonate minerals such as aragonite, dolomite, and siderite may be present. The Abakaliki Shale is the oldest formation and lies unconformably on the Basement Complex, notably Oban massif and Obudu plateau [46,47,[50][51][52][53] . It is characterized by bluish-grey black and black shales, sandy shales, fine micaceous and calcareous sandstone, and siltstone with limestone interbedding [43,[54][55][56] .…”