Water Quality Index, Hydrogeochemical Facies and Pollution Index of Groundwater in Port Harcourt, Niger Delta, River State, Nigeria

Abstract

Groundwater contamination by heavy metals presents a growing environmental and public health concern, particularly in regions like Port Harcourt, Nigeria, where groundwater is a primary source of drinking water. This study assessed heavy metal (HM) pollution in groundwater and its potential health implications by analyzing 18 water samples and corresponding tooth dentine from local residents. Laboratory analyses employed indices such as the Nemerow Pollution Index (NPI), Modified Degree of Contamination (MDc), Pollution Load Index (PLI), and Quantification of Contamination (QoC), alongside multivariate statistical techniques including Principal Component Analysis (PCA) and correlation matrices. Results revealed NPI values that categorized 85.9% of samples as heavily polluted, while mCd values showed that 41.5% had a very low degree of contamination, and 22.2% exhibited moderate contamination. PLI values indicated low pollution levels across all samples, whereas QoC analysis showed 100% negative values, pointing to geogenic sources as the dominant contributors. Multivariate correlation analysis highlighted weak but notable relationships among HMs and physicochemical parameters, suggesting complex geochemical interactions and potential anthropogenic influence. The spatial pattern of pollution, especially the north-to-south gradient observed in NPI values, aligns with localized human activities and natural geological factors. The overall assessment reflects some degree of heavy metal presence in the groundwater while the PLI depocts limited contamination, These findings underscore the urgent need for continuous groundwater monitoring and the deployment of appropriate treatment technologies to safeguard public health and prevent long-term ecological damage.