Browsing by Author "Anornu, G."
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Item Evaluation of water quality using hydrochemistry, stable isotopes, and water quality indices in the Lower Volta River Basin of Ghana(Springer Netherlands, 2018-06) Egbi, C.D.; Anornu, G.; Appiah-Adje, E.K.; Ganyaglo, S.Y.; Dampare, S.B.The Lower Volta River Basin of Ghana is an important international and local tourism destination. Communities in the basin depend on shallow aquifer systems, the Volta River, and nearby streams as their sources of water for domestic purposes, cattle watering, and irrigation. Due to increasing human activities and limited information on water quality in the area, a holistic assessment of the quality of the water resources in the basin was conducted using hydrochemistry, δ2H and δ18O, principal components analysis, and selected indices. EC ranged from 141 to 19,370 μS/cm and 60.9–986 μS/cm for shallow groundwater and surface water respectively. NO3 − levels above 45–1049.9 mg/l were observed in 45% of analyzed wells. Na–Cl- and HCO3–Ca-dominant facies are identified. Silicate weathering, evaporite dissolution, cation exchange, and salinity are the hydrochemical processes influencing the shallow groundwater in the area. δ2H–δ18O‰ plot showed meteoric shallow groundwater recharge. Ion ratios, EC, and Cl− versus δ18O‰ relationships suggest dissolution and seawater intrusion as causes of groundwater salinity. Hydrochemistry, principal components analyses, and NO3 − versus δ18O showed evidence of anthropogenic pollution on water in the basin. All analyzed surface water and 79% of well samples were within suitable range for irrigation. Based on the CCMEWQI model criteria, 85% of the surface water were in good-to-excellent categories while majority of the shallow groundwater were in fair, marginal, and poor categories. The combined approach provided vital information on water quality in the basin. Strategic control measures were proposed. © 2018 Springer Science+Business Media B.V., part of Springer NatureItem Hydrogeochemical evaluation of groundwater in the lower Offin basin, Ghana(Environmental Geology, 2008-02) Kortatsi, B.K.; Tay, C.K.; Anornu, G.; Hayford, E.; Dartey, G.A.Alumino-silicate mineral dissolution, cation exchange, reductive dissolution of hematite and goethite, oxidation of pyrite and arsenopyrite are processes that influence groundwater quality in the Offin Basin. The main aim of this study was to characterise groundwater and delineate relevant water-rock interactions that control the evolution of water quality in Offin Basin, a major gold mining area in Ghana. Boreholes, dug wells, springs and mine drainage samples were analysed for major ions, minor and trace elements. Major ion study results show that the groundwater is, principally, Ca-Mg-HCO3 or Na-Mg-Ca-HCO3 in character, mildly acidic and low in conductivity. Groundwater acidification is principally due to natural biogeochemical processes. Though acidic, the groundwater has positive acid neutralising potential provided by the dissolution of alumino-silicates and mafic rocks. Trace elements' loading (except arsenic and iron) of groundwater is generally low. Reductive dissolution of iron minerals in the presence of organic matter is responsible for high-iron concentration in areas underlain by granitoids. Elsewhere pyrite and arsenopyrite oxidation is the plausible process for iron and arsenic mobilisation. Approximately 19 and 46% of the boreholes have arsenic and iron concentrations exceeding the WHO's (Guidelines for drinking water quality. Final task group meeting. WHO Press, World Health Organization, Geneva, 2004) maximum acceptable limits of 10 μg l-1 and 0.3 mg l -1, for drinking water. © 2007 Springer-Verlag.Item Tracking nitrate sources in groundwater and associated health risk for rural communities in the White Volta River basin of Ghana using isotopic approach (δ 15 N, δ 18 O[sbnd]NO 3 and 3 H)(Science of the Total Environment, 2017-12) Anornu, G.; Gibrilla, A.; Adomako, D.In this study, we present a first attempt on the use of integrated hydro-chemical and isotopic technique to trace the sources of groundwater nitrate contamination in the Upper East Region of Ghana to aid the sustainable management of this vital resource. The objectives of the study are (1) assess the present status and spatial distribution of the nitrate contamination (2) identify and distinguish the most likely sources of nitrate , (3) identify the relationship between 3H and NO3- and F-, and (4) ascertain the potential human risk from exposure to nitrate contamination. The results showed that, nitrate concentrations varied from 0.42 to 431.17, 0.83 to 143.94, 0.03 to 28.94mg/l with mean values of 36.09, 21.54 and 5.01mg/l for boreholes, hand dug wells and the surface water respectively. These values showed that, about 95% of boreholes and hand dug wells and 45% of the surface water have nitrate concentration above the baseline value in the area. The NO3-/Cl- ratio showed that, 98.4%, 95% and 64% of the NO3- in the borehole, hand dug wells and the surface water are from anthropogenic activities. The δ15NNO3 and δ18ONO3- data confirmed that NO3- in the samples was predominantly derived from manure (human and animal waste) and denitrification occurring in some areas. The isotopic data further affirms the hydro-chemical interpretation that, chemical fertilizer and atmospheric deposition are unlikely sources of NO3- in the area. The relationship between 3H and NO3- concentrations showed that, higher NO3- values are associated with younger waters. Non carcinogenic health risk for adults and children posed by oral ingestion of the NO3- contaminated water revealed some degree of health risk, especially to children whose risk is about 72% higher. The study provides a conceptual model of the NO3- dynamics and some recommendation for groundwater management in the area.