Anthropogenic Platinum Enrichment in the Vicinity of Mines in the Bushveld Igneous Complex, South Africa

Abstract

South Africa is the world’s single largest platinum (Pt) producer owing to important resources in the Bushveld Igneous Complex (BIC). Little attention has been paid to the environmental impacts of mining in the region despite the extent of mining activities. Here, we present a study on the occurrence of Pt in the vicinity of mines in the BIC. Elevated concentrations were found at all sampling sites in the mining area. The highest Pt concentration in soil (698 ± 178 ng g−1, <125 μm) was found at a smelter, while processing plants, shafts and nearby towns had lower concentrations. Elevated Pt concentrations were also found in grass with a maximum of 256 ± 122 ng g−1 at the smelter and a significant correlation between soil and grass concentrations. In comparison, Pt concentrations in soil and grass at a background site were 2.7 ± 0.4 and 0.6 ± 0.2 ng g−1, respectively. Laboratory uptake experiments indicate that atmospheric deposition is the main source of Pt in grass. The occurrence of elevated Pt concentrations and its accumulation in vegetation raise concern over exposure of the local population through inhalation, skin exposure or dietary intake.