Overview
Makhadi and colleagues characterize potentially toxic element (PTE) contamination in soil and surface water around abandoned gold mine tailings dams in the Welkom Goldfield, Free State, South Africa. Gold is the mining context; the paper does not measure gold concentrations in soil or water. The measured analytes are arsenic (As), cadmium (Cd), chromium (Cr), Cu, lead (Pb), uranium (U), and Zn. Geoaccumulation indices and enrichment factors are computed to characterize contamination severity. This is a soil and water environment study, not a food occurrence study.
Key numbers
Soil PTE means across sites (mg/kg) include As approximately 18 to 34 depending on site, with geoaccumulation indices flagging As, Cr, and U as moderately to heavily contaminated at certain locations. Pb and U ranged from unpolluted to strongly contaminated based on comparisons with regional background and prior Witwatersrand Basin studies (Table S10, pp. 10 to 11). Anions including sulfate, bicarbonate, chloride, and fluoride were also characterized in water samples. LOD and LOQ values for the analytical method are reported on p. 5.
Methods summary
ICP-MS analysis for PTEs in soil and water matrices. Geoaccumulation index and enrichment factor calculations applied. Sampling sites distributed across the Welkom Goldfield area. The analytical method uses LOD/LOQ separation from solid residue.
Implications for the wiki
This paper supports Arsenic, Total, Lead, Chromium, and Uranium with soil environment data from the South African gold mining belt. It reinforces the finding from Okereafor et al. (2019) that abandoned gold mine tailings in South Africa generate PTE contamination plumes in surrounding soil. No food occurrence data are provided.
Related evidence
- Gold
- Arsenic, Total
- Lead
- Chromium
- Dataset on assessment of pollution level of selected trace metals in farming area within the proximity of a gold mine dump, Ekuhurleni, South Africa
Update history
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