Pollution Characteristics, Distribution and Ecological Risk of Potentially Toxic Elements in Soils from an Abandoned Coal Mine Area in Southwestern China

Minerals

卷:11

Xiao Guan¹  Libo Pan¹  Yanjun Chen¹  Ying Pei¹  Bo Liu¹  Zhenzhen Hao¹  Yi Zhang²  Jun Pan² 

[1] Ecological Department, Chinese Research Academy of Environmental Sciences, Beijing 100012, China;

[2] Water Department, Guiyang Bureau of Ecology and Environment, Guiyang 550000, China;

关键词: acid mine drainage;    abandoned coal mine;    potentially toxic elements;    pollution level;    potential ecological risk;   

DOI  :  10.3390/min11030330

来源: DOAJ

【 摘 要 】

Acid mine drainage (AMD) from abandoned coal mines can lead to serious environmental problems due to its low pH and high concentrations of potentially toxic elements. In this study, soil pH, sulfur (S) content, and arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), iron (Fe), manganese (Mn), and mercury (Hg) concentrations were measured in 27 surface soil samples from areas in which coal-mining activities ceased nine years previously in Youyu Catchment, Guizhou Province, China. The soil was acidic, with a mean pH of 5.28. Cadmium was the only element with a mean concentration higher than the national soil quality standard. As, Cd, Cu, Ni, Zn, Mn, Cr, and Fe concentrations were all higher than the background values in Guizhou Province. This was especially true for the Cd, Cu, and Fe concentrations, which were 1.69, 1.95, and 12.18 times their respective background values. The geoaccumulation index of Cd and Fe was present at unpolluted to moderately polluted and heavily polluted levels, respectively, indicating higher pollution levels than for the other elements in the study area. Spatially, significantly high Fe and S concentrations, as well as extremely low pH values, were found in the soils of the AMD sites; however, sites where tributaries merged with the Youyu River (TM) had the highest Cd pollution level. Iron originated mainly from non-point sources (e.g., AMD and coal gangues), while AMD and agricultural activity were the predominant sources of Cd. The results of an eco-risk assessment indicated that Cd levels presented a moderate potential ecological risk, while the other elements all posed a low risk. For the TM sites, the highest eco-risk was for Cd, with levels that could be harmful for aquatic organisms in the wet season, and may endanger human health via the food chain.

【 授权许可】

Unknown