Potentially toxic elements in weathered waste-rocks of Fushun western opencast mine: distribution, source identification, and contamination assessment

To understand the current status of the contamination of potentially toxic elements (PTEs) after closing the Fushun Western Opencast Mine, this study has focused on the concentration, contamination assessment, and source identification of eight PTEs in weathered waste-rocks in four distinct areas of the mine. The mean concentrations of Ni, Cr, Zn, Cu, Pb, Hg, Cd, and As were 79.4, 86.3, 126, 64.8, 16.9, 1.04, 1.94, and 6.27 mg kg(-1), respectively. The results demonstrated that Ni, Cr, Zn, Cu, Pb, Hg, Cd, and As were contaminated to different extents in different weathered waste-rocks and waste-rocks, among which there was considerable Cd contamination. Coal gangue area (CGA) exhibited the most polluted weathered waste-rocks, which can be attributed to severe pollution and moderate ecological hazards. Self-combustion gangue (SCG) contamination of waste-rocks was considerably serious and caused severe pollution and considerable ecological harm. Health risk assessments demonstrated that Hg had the highest non-carcinogenic risk. Ingestion of PTEs was found to be a primary route of exposure, while dermal and inhalation exposure was negligible. Principal component analysis (PCA) demonstrated that there were roughly three sources of PTEs in the weathered waste-rocks of the mine, natural sources related to the weathering of parent rocks, and human sources, including industrial emissions, mining activities, and atmospheric dust deposition and resuspension. This study advances our knowledge of PTEs in mines and provides policymakers with a reference for designing strategies to protect mine-based ecosystems.

Automated summary

This study focused on the contamination of potentially toxic elements (PTEs) in weathered waste-rocks from the closed Fushun Western Opencast Mine, revealing varying degrees of contamination in different areas. The primary exposure route for PTEs was found to be ingestion, with Hg posing the highest non-carcinogenic risk. The analysis also identified three main sources of PTE contamination in the waste-rocks, including natural weathering processes and human activities such as industrial emissions and mining.