A comprehensive assessment of groundwater quality for drinking purpose in a Nigerian rural Niger delta community

Abstract

This study gives a first time comprehensive report on the quality of groundwater in Emevor community in the Niger Delta region of Nigeria, for dry and wet season monitoring. Water samples were collected from ten (10) bore-holes (BHs) and 10 hand-dug wells (HDWs), on monthly basis, for eight (8) consecutive months spanning from May to August, 2016 (wet season) and October 2016 to January 2017 (dry season). Following standard procedures, thirty-three (33) water quality parameters were analyzed. But for pH being less and Ba higher than the prescribed values of the WHO and SON, all other physicochemical parameters were within the WHO and SON standards. While the low pH value was linked to mineral dissolution, the high Ba value was attributed to oil exploration activities in the area. The main mineral classes in the aquifer (Calcium-Iron, Sodium-Magnesium and Zinc-Potassium) were found to be the determinants of the groundwater chemical composition and ionic exchanges. ANOVA showed a significant difference in the concentration of parameters that exceeded regulatory limits for BHs and HDWs. Microorganisms isolated from the water samples obtained from BHs and HDWs are Enterobacter aerogenes and E. coli. The higher organic pollution recorded for the HDWs corroborated the higher values of E. coli obtained. By implication, this study shows that BHs were safer drinking water sources in the community. Regular monitoring of groundwater in Emevor and neighbouring communities is recommended given the increase in anthropogenic activities in the area of study.