Integrated Geophysical and Hydrogeochemical Characterization and Assessment of Groundwater Studies in Adum West Area of Benue State,Nigeria

Abstract

Integration of geophysical and hydrogeochemical methods has been scientifically proven to be useful in vulnerability study and groundwater characterization. Subsurface geoelectric parameters such as resistivity and thickness obtained from geophysical method (Vertical Electrical Sounding VES) was used to determine aquifers vulnerability, longitudinal resistance (ρL) and transverse unit resistance (Rt). Thirty four water samples were collected from groundwater sources for physicochemical analysis.Estimated results from longitudinal conductance (S), (Rt) and (ρL) showed that the values ranges from 0.03 to 2.5mhos, 103.64 to 1964417.8 Ω/m2 and 215.41 to 65731.68 Ω-m respectively. Result from S suggested that 50 % of groundwater is considered to be vulnerable to contamination from the earth surface, while the remaining 50 % is considered to be slightly vulnerable to surface contamination. Further findings obtained from hydrogeochemical analysis such as Gibb’s and Chadba plots revealed that groundwater is highly influenced by rock water interaction,groundwater is classified to be Na+ + HCO3¯, Ca2+ + Mg2++ HCO3¯ , Na+ + Cl¯ and Ca2+ + Mg2+ + Cl¯ water type. Deduction from Soltan classification suggested that groundwater is classified to be of Na+ ˗ HCO3¯ and Na+ ˗ SO4 2¯ water type. Results obtained from Ec and pH suggested that the values were below WHO permissible limit, while result obtained from TDS showed that at some sampling points TDS values were above WHO limit. Based on pH value obtained groundwater within the study area fell within slightly basic to acidic.