Abstract

Twenty five samples of groundwater were obtained from various boreholes in the study area and subjected to physico-chemical analysis using standard laboratory techniques. The study was aimed at the assessment of the pollution status of the groundwater supply in parts of Imo River Basin and its environs using some pollution indications namely: electrical conductivity, phosphate (PO₄), total dissolved solids (TDS), nitrate (NO₃^--), sulphate and turbidity. The values of the physico-chemical parameter were correlated with the World Health Organisation (WHO) values. The result shows that the level of pollution is relatively high in Owerri. The highest concentration of electrical conductivity and nitrate were obtained at Owerri. The highest concentration of phosphate was observed at Mbaise area. The most saline part is the southern part proximate to the delta area. Moderate to higher values of TDS were observed at the densely populated areas of Owerri, Umuahia and Aba. Electrical conductivity in Owerri ranged from 101 to 181.6 NS/cm which exceed the WHO standard of 100 NS/cm. Phosphate levels exceeding the WHO standard of 5 mg/L were observed at the Mbaise axis. No borehole location exceeded the required maximum standard for TDS which show general stability.

Key words: Groundwater, physico-chemical analysis, pollution status, Imo River Basin, borehole.