Human health risk via soil ingestion of potentially toxic elements and remediation potential of native plants near an abandoned mine spoil in Ghana

Abstract

Integrated studies about potentially toxic elements (PTEs) in sites near gold mining spoils, their contamination and human health risk, as well as remediation potential of native plants are limited. Therefore, our aim was to assess the human health risk of PTEs (Al, As, Cd, Cr, Cu, Fe, Ni, Pb, Ti, V, and Zn) in sites near an abandoned gold mine spoil in Ghana. We collected 52 soil samples near the mine spoil and from a natural forest, determined their total element contents, and calculated the soil contamination factor (CF), enrichment factor (EF), geo-accumulation index (Igeo) and the pollution load index (PLI). In addition, we calculated the human health risk of soil ingestion for adult males, females, and children using the hazard quotient (HQ) and hazard index (HI). We also assessed the phytoremediation potential of five native plants (Alchornea cordifolia, Chromolaena odorata, Lantana camara, Pityrogramma calomelanos- fern, and Pueraria montana) growing near the mine spoil, and calculated their transfer coefficient (TC) and translocation factor (TF). Total content of As (maximum: 3144.0 mg/kg) surpassed the trigger action value of 65 mg/kg. Total Zn content at 90th percentile in the Pueraria field (197 mg/kg) and maximum value at mine surrounding (76.7 mg/kg) were above the world soil average (70 mg/kg). Pollution load index and EF values indicated severe levels of soil contamination particularly with As and Ti. Hazard index (HI) values for all sites for children (0.7–134.56), adult males (0.05–10.6), and adult females (0.13–12.77) were above 1 and indicated high human health risk especially on children and women. Translocation factor shows that native plant species such as Chromolaena odorata and fern accumulated As, Cu, Ti, and Zn into their shoots and may thus have the potential to reduce the high soil contamination and its associated human health risk.