Modelling the Groundwater Quality in parts of Eastern Niger Delta, Nigeria using Multivariate Statistical Techniques

Abstract

Groundwater pollution is one of the environmental problems facing many coastal regions such as Niger Delta as a result of high population, urbanization and industrialization. The quality of groundwater in the Eastern Niger-Delta, Nigeria was investigated in this study using multivariate geostatistical techniques. Hydrogeological investigations show that the aquifers in the area are largely unconfined sands with intercalations of gravels, clay and shale. These findings indicate that the aquifer in the area is porous, permeable and prolific. 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. Heavy metal enrichment index revealed 12 elements in the decreasing order of: Fe > Ni > Cu > Zn > Mn > Cd > V > Co > Pb > Cr > As > Hg. The study identified salt intrusion, high iron content, acid-rain, hydrocarbon pollution, use of agrochemicals, industrial effluents 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 four factors are results of various anthropogenic activities domiciled in the area. Owing to the monumental and devastating effects of hydrocarbon pollution in the area, the need to eradicate gas flaring and minimize oil spills in the area was advocated. The geostatistical evaluation approach employed in this study gave rise to the development of groundwater vulnerability map of Eastern Niger Delta. Communities where their boreholes have been contaminated by hydrocarbon should stop using such wells and government should provide them with alternative source of water for drinking and domestic purposes.