Migration Mechanism And Environmental Effects Of Heavy Metals Around An Antimony Mine Area In Central China

Long-term antimony mining and smelting have led to very serious heavy metal pollution.The spatial distribution and transport characteristics of heavy metals in an antimony mine area(Xikuangshan,China)were systematically studied using a field survey and geostatistical analytical methods.In the study area,52 soil and sediment samples were collected from bare land,grassland,woodland and river sediments covering a surface area of 20 km2.The soil properties and heavy metal concentrations were measured by wavelength dispersive X-ray fluorescence spectrometry and inductively coupled plasma-mass spectrometry,respectively.Anthropogenic activities have produced large quantities of mine wastes that contain a number of heavy metals.Correlation analysis and principal component analysis suggest that Cu,Zn,Cd,As,Pb and Sb can be attributed to anthropogenic inputs,whereas Cr,Mn and Ni are of natural origin.Sb also displayed a strong correlation with As,which could imply similar geochemical behaviors for the transport and deposition of Sb and As.In addition to the influence of heavy metal accumulations in soils,fluvial and atmospheric transport processes are also important problems.Distribution maps of heavy metals were generated using the Kriging interpolation method to identify their distribution trends.The results show the influence of wind,river,distance and vegetation on the spatial distribution.The results also revealed that windborne transport may play a significant role in the spreading of contaminants.The mobilization of metal-bearing mine wastes can be expected to elevate metal concentrations in soils as a result of the aeolian erosion and leaching of mine tailings.Fluvial erosion and transport can play a key role in governing the mobilization and dispersal of heavy metals,and modifying their concentrations through dilution,whilst alluvial strores can become important secondary repositories.Heavy metal contaminants are transported from the Lianxi River to the Zi River.Moreover,heavy metals are released into the proximal atmosphere,fluvial and soil systems,causing adverse impacts on ecosystems.