Assessment of land-use impacts on groundwater quality in parts of Port-Harcourt city, SE-Nigeria

This study offers insights into the geochemistry and quality status of groundwater in Port Harcourt, situated in the sedimentary Niger Delta region in southern Nigeria. Groundwater was gathered at sampling sites in the city's residential, commercial, industrial, and remote areas that crossed over important land-use zones. Chemical analyses of the samples show that the waters vary in nutrient amounts and have traces of salt water intrusion. The waters are slightly acidic; chemical parameters and nutrient within limits of potable water. Cations and anions, respectively, are dominated by Ca > Mg > K > Na and Cl > HCO₃>SO₄>NO₃. The heavy metals Pb, Cu, Zn, Cr, and Cd, revealed concentrations generally above acceptable limits, with the industrial areas reporting the highest concentration levels. Principal component analysis and correlation indicate presence of interrelationships among chemical species, linked to salinity, silicate weathering, and anthropogenic controls, and primarily responsible for the chemistry of water. Groundwater in the research area is classified as Ca–Mg–Cl–SO₄ type by the hydrochemical facies plot. Water quality index (WQI) calculations show that different land-use zones have varied degrees of poor water quality. According to Pollution Index (PI) assessments, anthropogenic activities in and around the city are the reason for the high level of pollution in the groundwater.