Geospatial Assessment of Heavy Metal Concentration in Groundwater of Kaduna South Local Government, Nigeria

Abstract

Water is an essential natural resource that supports human life, economic activities, and ecosystem functioning. However, groundwater quality is increasingly threatened by heavy metal contamination arising from anthropogenic activities. This study presents a geospatial assessment of heavy metal concentrations in groundwater within Kaduna South Local Government Area (LGA), north-western Nigeria. A total of thirty (30) groundwater samples were collected from boreholes and hand-dug wells and analysed for Zinc (Zn), Chromium (Cr), Cadmium (Cd), Lead (Pb), Iron (Fe), and Copper (Cu) using Atomic Absorption Spectrophotometry (AAS). Geographic Information System (GIS) techniques, specifically Ordinary Kriging interpolation, were employed to model spatial distribution patterns. Results revealed significant spatial variability, with elevated concentrations of Cr (0.23-0.25 mg/L), Cd (0.18-0.23 mg/L), Pb (3.65-4.73 mg/L), and Fe (3.92-7.04 mg/L) forming contamination hotspots in industrialised wards such as: Kakuri, Makera, Sabo, and Tudun Wada. In contrast, Zn (0.29-0.46 mg/L) and Cu (0.36-0.53 mg/L) remained within WHO and SON permissible limits. However, Cd, Pb, and Fe exceeded recommended thresholds in a substantial proportion of samples, indicating potential public health risks. The spatial patterns suggest strong anthropogenic influence, including industrial discharge, poor waste management, and infrastructure deterioration. This study demonstrates the effectiveness of geospatial techniques in groundwater quality assessment and provides critical data for sustainable groundwater management and public health protection.