[Source Apportionment of Heavy Metal Pollution in Farmland Soil of a Stone Coal Mining Area and Its Surrounding Area...

To investigate the potential risk of heavy metal contamination in agricultural soil resulting from stone coal mining activities, soil samples were collected and analyzed from a stone coal mining site and its surrounding areas. The findings revealed that： ① The risk of heavy metal pollution in the vicinity of the stone coal mining area was notably high, with 61.6% of sampling sites exhibiting moderate to severe pollution as determined by the Nemerow composite pollution index, including 21.9% showing significant levels of contamination. Soil contamination with Cd within the study area was particularly severe, with 71.5% and 18.5% of sampling sites exceeding risk screening and control values, respectively. Some soil samples also indicated potential risks associated with Cu and Zn, while individual samples showed excessive levels of As, Pb, Hg, and Ni. ② There were highly significant positive correlations observed between soil Cd, Zn, Ni, Cu, and As； As-Hg-Pb； as well as Cr-As-Ni-Hg pairs, respectively. No significant correlations were found between the Cd-Cr or Cd-Pb pairs； however, other combinations involving different heavy metals exhibited notable positive associations, suggesting similar sources for their pollution origins. ③ Three distinct sources contributing to soil heavy metal pollution within the study area were identified utilizing two receptor models-namely stone coal mining activities, atmospheric deposition events, and natural sources, such as weathering processes According to APCS-MLR model analysis results, soil concentrations of Cd-As-Cu-Zn-Ni were primarily affected by stone coal mining activities, while Pb-Hg were mainly influenced by atmospheric deposition events, and Cr was predominantly impacted by natural sources alone, with each source contributing approximately 43.2%, 31.5%, and 25.3%. PMF model outcomes generally aligned closely with these findings, suggesting soil Cd and Hg originated from combined effects related to both stone coal-mining activity and atmospheric depositions. Each source contributed rates around 45.0%, 34.5%, and 20.5%. This research underscores a substantial threat posed by heavy metal contamination in farmland soils adjacent to stone coal mines and highlights how employing multiple receptor models can provide more accurate determination regarding primary sources responsible for heavy metal pollutants present within each specific location.