HYDROGEOCHEMICAL SIGNATURES AND QUALITY ASSESSMENT OF GROUNDWATER IN OKPOKO
AND ENVIRONS, SOUTHEASTERN NIGERIA
Journal: Pakistan Journa l of Geology (PJG)
Author: Nwankwoala, H. O, Ememu, A. J
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
This study is aimed at assessing the hydro-geochemical signatures of groundwater in Okpoko and Environs in Anambra State, Southeastern Nigeria. Fifteen groundwater samples were collected and analyzed for physico-chemical, heavy metals and hydrocarbon content. Heavy metals in groundwater were analyzed using Atomic Absorption Spectrometer. The groundwater analyses revealed that average pH (6.05), Fe (0.68 mg/L) and Ni (0.028 mg/L) values exceeded WHO and NSDWQ guidelines. Total Petroleum Hydrocarbons (TPH) in groundwater were relatively very low and recorded only in BH1 (0.04 mg/L) and BH2 (0.002 mg/L) and below detectable limit for all other sampled boreholes. Piper diagram revealed two hydro-chemical facies: Mg-HCO3 and Ca-HCO3 rich water, while Stiff diagrams confirmed four distinct water types (Ca2+, Mg2+, HCO3; Ca2+, HCO3; Ca2+, Na++K+, Cl-, HCO3; Ca2+, Cl- Class). Gibb’s diagrams revealed that chemical weathering of rock and precipitation are the major influences on the groundwater quality. The various ionic ratios: Mg/Ca (0.56), HCO3/Cl (3.31), (Na + K)/Cl (1.45), Na/K (1.61), Ca/Na (7.0), SO4/Cl (0.67) and CEV (-0.45) suggests the groundwater sources are of inland origin. Groundwater flow direction shows that the area is drained by the Niger River on the western part of the study area.