A GIS-BASED APPROACH FOR GEOSPATIAL MODELLING OF HEAVY METALS CONTAMINATION IN GROUNDWATER QUALITY AROUND SAGAMU INDUSTRIAL AREAS, SOUTHWESTERN NIGERIA

Groundwater is the main source of water for domestic use in Nigeria because it is perceived to be clean. The presence of heavy metal contaminants, and the level of awareness of their presence in groundwater around industrial areas in Sagamu, Ogun State, Nigeria was examined in this study. A total of twenty (20) groundwater samples were collected from hand dug wells which tap into shallow aquifers and their location taken with the aid of a GPS. GlS-based method such as ArcGIS technology was adopted to analyze the spatial distribution of heavy metals in groundwater and to evaluate potential health risks. The results were compared with the WHO standard. Results showed that chromium ranged from 0. 01 to 0. 53 mg/L, copper (0.12 – 1.89 mg/L), nickel (0.04- 1.94 mg/L), zinc (0.04 -2.55 mg/L), and, lead (0.001 - 0.03 mg/L).The spatial distribution maps revealed significant heavy metal contamination (chromium, lead, nickel, copper, and zinc), exceeding WHO permissible limits in the southern part and declining towards the north, and west of the study area indicating localized source of contamination likely from domestic, industrial, and agricultural sources. The correlation matrix results showed that there exists a weak and positive correlation among elements, revealing the relationship among the heavy metals to their sources of origin. This study highlights the need to develop strategies for the effective management of water resources to mitigate anthropogenic impacts and safeguard human health in the area.