Browsing by Author "Egbi, C.D."
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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 Nitrate contamination of groundwater in the Lower Volta River Basin of Ghana: Sources and related human health risks(Ecotoxicology and Environmental Safety, 2020-01-22) Ganyaglo, S.Y.; Egbi, C.D.; Anornu, G.K.; Appiah-Adjei, E.K.; Li, S-L.; Dampare, S.B.A significant population within the Lower Volta River Basin of Ghana relies solely on untreated groundwater (GW) and surface water (SW) for various purposes. However, negative practices associated with increasing human activities pose threats to particularly GW quality in the basin. Using NO3 − as a proxy, this study mainly focused on the status of GW contamination, origins of NO3 − and potential human health risks through integrated hydrochemistry, correlation analysis, isotopes (15N, δ18O), Bayesian and USEPA human health risk models. Slightly acidic to alkaline GW and SW environments were observed. Electrical conductivity (EC) values above 1000 μS/cm were recorded in 45% of the GW with a maximum of 19370 μS/cm. NO3 − in GW ranged from 0.12 to 733 mg/L with average 59.6 mg/L and positively correlated with K+, Ca2+, Mg2+, Cl−, Na+ and EC. In SW, a maximum of 5.3 mg/L of NO3 − was observed. Largely, 75% of the GW exceeded local background NO3 − value of 2.1 mg/L, while 35% were above the WHO recommended value of 50 mg/L. Bivariate and correlation relationships elucidated human contributions to sources of NO3 −, Cl−, SO4 2− and K+ to GW in the basin. From NO3 −/Cl− ratio, 43% of the GW and 21% of SW were affected by effluents and agrochemicals. Values for δ15N–NO3 - and δ18O–NO3 - ranged from +4.2‰to +27.5‰and +4.5‰to +19.9‰for GW, and from +3.8‰ to +14.0‰and +10.7‰to +25.2‰for SW. Manure, septic effluents and mineralized fertilizers are sources of NO3 − contamination of water in the basin. The Bayesian model apportioned 80% of GW NO3 − contamination to sewage/manure. Hazard index indicated 70%, 50% and 48% medium to high-risk levels for infants, children and adults respectively, with 79% high-risk of SW NO2 − contamination to infants. Immediate measures for GW and SW quality protection are recommended.Item Trace Metals Migration and Contamination Assessment of Groundwater in the Lower Volta River Basin, Ghana(Exposure and Health, 2021) Egbi, C.D.; . Anornu, G.K.; Appiah‑Adjei, E.K.; Ganyaglo, S.Y.; Dampare, S.B.This study was conducted to assess the migration of trace metals (TMs), their sources and potential human health risks in the Lower Volta River Basin (LVRB) of Ghana using preference technique, geometrical analysis, hydrochemistry, TMs evaluation index, correlation matrix and USEPA risk assessment model. Results of enrichment evaluation and geometrical analysis revealed that Fe, Mn, Pb and Ni are the dominant TMs within the unsaturated zone. Moderate vertical migration trends of Pb and Ni in agreement with hydraulic conductivity and Cl− were also displayed. The distribution of the TMs on Ficklin diagram suggests that their dissolution is less depended on the groundwater acidic environments. The mean dominance of the TMs in the groundwater follows the order of Fe > Mn > Ni > Cu > Pb > Zn. Results of TM evaluation index showed that 37%, 57% and 6% of the groundwater are of low, medium and high pollution categories. The hydrochemistry, correlation, biplots and three-dimensional plot jointly revealed that Pb, Ni and Mn occurred in the groundwater as migrating constituents of effluents and agricultural inflows. Also, hydrogeochemical conditions favour vertical migration of Fe. Results of non-carcinogenic risk quotients showed that 6%, 9%, 43% and 100 of the groundwater were above unity for Fe, Mn, Ni and Pb. Hazard index values were > 1 for all human categories. Pb and Ni showed high potential non-carcinogenic risk. Also, Ni showed greater cancer risk for all age groups. The study is key to preventing groundwater quality depletion in the basin.