Geoenvironmental and health risks associated with toxic metals in goldmine site of Iperindo, southwestern Nigeria

Abstract

Mineral exploitation enhances the nation’s economic growth and development but poses serious threats to the environment thereby leading to ecological imbalances and public health risks. This study evaluates heavy metal pollution in an abandoned gold mining site of Iperindo, Southwest Nigeria and associated environmental and health risks were investigated. Soil samples collected at the site were subjected to a total digestion technique and analyzed for metals (As, Pb, Cd, Cr, Cu, Zn, Co, Ni, and Fe) using AAS. Only SS15 had a baseline pollution level while all other sampling points had significant heavy metal pollution. Generally, the analysis showed that 33.3% and 66.7% of the sites are included in the unpolluted and moderately polluted classes respectively for As, Cr, Cu, Co, and Ni. For Cd and Zn, 13.3% of the sites were in unpolluted class while it was 40.0% and 66.7% for Pb and Fe respectively. By implication, the highest ecological risk was at SS3 while metal that posed the highest ecological risk was Cd. HQ estimated for all metals via ingestion and dermal pathways for both adults and children were > 1 but < 1 via inhalation pathways in both age groups. However, the values were greater in children than adults. This suggested that oral and dermal exposures to As, Pb, Cd, Cr, Cu, Zn, Co, Ni and Fe in the soil of the study area would elicit non-carcinogenic adverse health hazard. This result shows the critical need to carry out remediation of the study site despite the abandonment of mining operations to protect possible health hazards, particularly to children.