Hydrogeochemistry of shallow groundwater in Kurgwi and environs, North-central Nigeria

A hydrogeochemical study of groundwater was carried out in Kurgwi and Environs. The aim of the study was to determine the chemical composition of the various water sources in the area and their suitability for domestic, industrial and agricultural purposes. Forty (40) water samples from shallow (hand-dug) wells were collected and analysed. Major cations and trace elements were analysed using the Inductively Coupled Plasma Optical Emission Spectrometer and the anions and bicarbonate were determined by double VV-visible spectrophotometer (Hitachi model 2000).and titration methods respectively. Results of laboratory analysis and plots on Piper Trillinear diagrams show the dominant water type in the area to be Ca-Na-HCO3 water. Physico-chemical parameters of waters in the areas show most concentrations are within WHO permissible limits for drinking. However, calcium, potassium, TDS, total hardness and electrical conductivity are above the WHO upper limits in few locations and so are aluminium, iron, and manganese. Geogenic sources as well as minor anthropogenic activities have been observed to be the major control on the composition of groundwater in the area. Groundwater in the area is generally not very suitable for domestic purpose such as laundry, but is suitable for livestock and irrigation purposes.Keywords: Hydrogeochemical, Groundwater, Concentration, Total Hardness, Major Cation

Hydrogeochemical appraisal of fluoride in groundwater of Langtang area, Plateau State, Nigeria

Consumption of high fluoride in groundwater of Langtang area, manifest in the inhabitants of the area in form of dental fluorosis and skeletal fluorosis in older group. The aim of this study was to appraise the hydrogeochemistry of fluoride in the groundwaters of Langtang area. Thirty seven surface and groundwater samples and nine rock samples were collected in Langtang area for geochemical analysis. The Inductively Coupled Plasma Emission Spectrometry (ICPOES) was used to detect cations. The anions (Cl-, SO4 = and Br-) were determine by Ion Chromatography method. Fluoride was determined by the Specific Ion Electrode and bicarbonate was determined by titration. Major oxides, trace elements and rare earth elements for the rock samples were determined by the XRF method and fluorine by the Fusion method. Polished thin sections for rocks were prepared and studied. Geochemical results from analysis of the samples (rock and water) show that four major rock units make up the geology of the area; coarse porphyritic biotite granite, migmatite, rhyolite and riebeckite granites, the minor ones are pegmatite, trachyte, aplite and fine to medium grained biotite granites. The rhyolite, the riebeckite granites and trachyte have the highest level of fluorine content in the area (1,470, 1000, 900 and 800 ppm) respectively. The fluorine mineral (Fluorite) crystallized in the late stage of the magma as replacement of Fe/Mg mineral probably hornblende or biotite. Fluorine is leached into the groundwater from the rhyolite under the slightly alkaline (Ca-Mg-HCO3 evolving Na-HCO3) water in the area. The two major groundwater types (Ca-Mg-HCO3 and Na-HCO3) in the area have good relationship with content of fluoride in water. Although, the riebeckite granites have high fluorine content, contribution of fluoride from them is towards the southern portion of the map, owing to the groundwater flow direction. The different water sources in the area do not show variation in content of fluoride in water. However, groundwater barriers (dykes) may be responsible for some area having low fluoride (<1.5 mg/l) content. The consumption of high content of fluoride in the area has resulted in severe dental fluorosis in both children and youths and bowing of legs (Genu Valgum) in children with no discrimination between the sexes.Keywords: Fluoride, Fluorite, Fluorine, Fluorosis, Riebeckite Granite, Groundwate