The Petaquilla gold mine in Panama was abruptly closed without restoring the site. The objective of this study is to assess mine soils from a geochemical perspective, identify potential contaminants, and conduct a human health risk assessment (HHRA). Soil samples were analysed to determine pH, EC, OM, texture, hydrocarbons (TPHs), enzymatic activity (DHA), and the following potentially toxic elements (PTEs): As, Ba, Cd, Cu, Hg, Sb, Pb and Zn. The Igeo, PLI and HHRA indexes were evaluated. The Igeo indicates that the processing zone has atypical values of Cu (1.47), indicating moderate pollution (1 5), with enrichment due to mining activity. The PLI map shows that the affected areas are surrounding the Molejon River (1.62) and the processing zone (1.21), which are slightly contaminated (1 ≤ PLI < 2), and one site in the processing zone with moderate to considerable contamination (PLI ≥ 3) at the warehouse (6.07). Regarding TPHs, the processing area in front of transformer (54,844.47 mg kg−1) and the workshop entrance (2045.26 mg kg−1) have values above industrial use (620 mg kg−1) due to visible hydrocarbon spills. In terms of HHRA, the non-carcinogenic risk associated with exposure to PTEs exceeds the reference threshold for both children and adults under a residential exposure scenario, whereas the non-carcinogenic risk for TPHs remains below the acceptable limit. Regarding carcinogenic risk, exposure to Pb and As remains within acceptable limits for both receptors. With a view to restoring the mine’s soil, the processing area and the workshop entrance are the first areas that need to be addressed.
González-Valoys et al. (Thu,) studied this question.