Hydrogeochemistry of the Geologic Profiles of Enwan and Environs, Akoko Edo, South South Nigeria

Abstract

Hydrogeochemical investigation as well as petrographic examination of rock samples was carried out in Enwan and environs, in Akoko Edo, South South Nigeria. Ten (10) water samples and two (2) rock samples were collected from study area for analyses. All of the samples collected were subjected to geochemical and petrographic analysis respectively, Physical parameters such as pH, TDS, Electrical conductivity and temperature were measured in situ using standard equipments and the analysis for the chemical parameters was carried out with Atomic Absorption Spectrometer (AAS). The concentration of metals in the samples was determine through geochemical analysis the correlation of physical and chemical parameters. Ca2+, Mg2+, K+, Na2+, Fe2+ and Cu2+ were the cations analyzed for while the anions included HCO3, NO3 and Cl . The results were compared with the world Health Organization (WHO) and Nigerian Industrial Standard (NIS) standards to determine the quality of the groundwater. ENW4 had the relatively highest calcium and magnesium ions concentration. ENW3 and ENW4 have the relatively highest chloride ion concentration, but all the samples have extremely high chloride concentration. The anthropogenic sources from which the high concentration
of these parameters such as Chloride, Iron, Electrical conductivity and pH
were found could either be as a result of the human activit ies in this study
area or weathering of rock forming minerals such as Biotite, Quartz,
plagioclase. The source of contamination of Iron in the groundwater is from
weathering of surrounding rocks and subsequent leaching into the aquifer.
During weathering, because feldspars are not resistant to weathering unlike
quartz that are very resistant, it gives off Na + and K + which are then
washed down into the groundwater through percolation. The Piper plot
shows that the all the samples belong in the Ca 2+ Mg 2+ Cl hydrochemical
facies which results to an area of hardness because of the magnesium and
chloride ions.