Heavy Metal Contamination of Urban Slum Groundwater: A Case Study of Ijora, Badia, Lagos

Abstract

This study assessed groundwater sources within the urban slum settlement of Ijora Badia, Lagos, to evaluate heavy metal contamination levels in relation to the attainment of Sustainable Development Goal (SDG) 6, which emphasizes access to safe and clean water. Groundwater samples were collected from six representative sources comprising three wells and three boreholes: Badia East Well (BEW), Badia Central Well (BCW), Badia West Well (BWW), Badia East Borehole (BEB), Badia Central Borehole (BCB), and Badia West Borehole (BWB). The concentrations of selected heavy metals—Lead (Pb), Cadmium (Cd), and Iron (Fe)—were determined and compared with the permissible limits recommended by the World Health Organization. Results showed that Pb concentrations ranged from 0.00 to 0.66 mg/L, Cd from 0.00 to 0.021 mg/L, and Fe from 0.00 to 12.50 mg/L. The highest concentrations of Pb (0.66 mg/L), Cd (0.021 mg/L), and Fe (12.50 mg/L) were recorded in the Badia Central Borehole (BCB). Most of the groundwater samples exceeded the WHO permissible limits for the analyzed heavy metals, with the exception of samples from Badia West Well (BWW) and Badia Central Well (BCW), which complied with the guideline values. These findings indicate the presence of heavy metal contamination in groundwater sources within the study area. The contamination may be attributed to anthropogenic activities such as leachate infiltration from waste disposal sites and industrial effluent discharges, although natural geogenic sources cannot be ruled out. Consequently, further investigations are recommended to identify the specific sources, pathways, and extent of heavy metal pollution in the area and to develop appropriate mitigation measures for safeguarding public health and groundwater quality.