Human health and environmental assessments of small-scale and artisanal mining activities in the Gold City of Ijeshaland, Southwestern Nigeria

Abstract

Background: This study assessed the health and environmental impacts of artisanal gold mining in Ijesha-land, Osun State, Southwestern Nigeria. Fifty-four environmental samples were collected between 2011 and 2012 and analyzed for major, trace and rare earth elements using standard procedures. Samples were collected from surface water (rivers and streams), groundwater, bottom sediments, fish (Tilapia) and aquatic plants (ferns). Data collected were analysed for simple descriptive and inferential statistics using Statistical Package for Social Sciences (SPSS) for Windows (16.0). Human health risk assessment of noncarcinogenic adverse effects of elements in water and fish samples was determined. Results: Higher concentrations of most major and trace elements were found in groundwater than surface water, while rare earth elements (REEs) were more concentrated in groundwater than surface water. Bottom sediment samples showed highest concentrations of Ti, Cs and Eu for major, trace and rare earth elements, respectively. The major and trace elements were most concentrated in the fish guts. The sum of REEs was observed highest in the fish guts (31.83 ± 35.90 µg kg−1), followed by muscle (18.70 ± 19.37 µg kg−1), while the lowest ΣREEs was measured in the gills (15.78 ± 22.45 µg kg−1). The human health risk assessment revealed low hazard quotient and hazard index values less than 1.0 for trace and rare earth elements in environmental samples. Conclusions: The data obtained in this study showed that, the artisanal gold mining activities in the study area may contribute to long term environmental and human health risk.