Hydrochemical Facies Classification and Groundwater Quality Studies in Eastern Niger Delta, Nigeria

Abstract

Soil and water pollution are major environmental problem facing many coastal regions of the world due to high population, urbanization and industrialization. The hydrofacies and water quality of the coastal plain-sand of part of Eastern Niger-Delta, Nigeria was investigated in this study. Hydrogeological investigations show that the aquifers in the area are largely unconfined sands with intercalations of gravels, clay and shale which are discontinuous and however form semi-confined aquifers in some locations. The observed wide ranges and high standard deviations and mean in the geochemical data are evidence that there are substantial differences in the quality/composition of the groundwater within the study area. The plot of the major cations and anions on Piper, Durov, and Scholler diagrams indicated six hydrochemical facies in the area: Na-Cl, Ca-Mg-HCO3, Na-Ca-SO4, Ca-Mg-Cl, Na-Fe-Cl and Na-Fe-Cl-NO3. The groundwater quality of the area was evaluated using water quality index. The study identified salt intrusion and high iron content and poor sanitation as contributors to the soil and water deterioration in the area. Saltwater/freshwater interface occurs between 5 m to 185 m while iron-rich water is found between 20 m to 175 m. The first two factors are natural phenomenon due to the proximity of the aquifer to the ocean and probably downward leaching of marcasite contained in the overlying lithology into the shallow water table while the last factors is the results of various anthropogenic activities domiciled in the area. The peoples in the region are advised to imbibed good hygiene and sanitary habit.