Abstract:
Heavy metal pollutants in open-pit tailings can spread to surrounding areas through dust and rainwater runoff, posing a risk of heavy metal accumulation in plants and threatening environment and human health. This study used atmospheric dustfall data collected from the dust collection tank of the tailing storage facility at the Yaoxianzi copper mine in August 2020, along with samples of surrounding plants, to measure heavy metals (Pb, Cr, Cu, Ni, As, Ag, Cd, Hg) in both atmospheric dust and the plants. By employing Spatial Interpolation method, Analysis of Variance, and regression analysis, the spatial distribution characteristics and factors influencing heavy metals in atmospheric dust were analyzed. The heavy metal enrichment characteristics of typical shrubs around tailings were clarified, and the influence of the enrichment characteristics of heavy metals in plants was clarified. The results showed that: (1) The distribution of heavy metals in atmospheric dust around copper tailings was uneven, with higher concentrations primarily in the southwest and southeast regions of the tailings reservoir.The heavy metal conntent is 15.82% to 83.68% exceeding than the soil background values in Ningxia. (2) The distribution of heavy metals was influenced by terrain, vegetation, distance, and meteorological factors, with wind speed and distance as the dominant factors. Higher wind speed and elevated slope positions correlated positively with the heavy metal content in dust, while vegetation coverage, relative humidity, and distance correlated negatively. High wind speed, steep slopes, and lack of vegetation increased heavy metal concentrations, while vegetation and slope affected dust size. (3) Different plant species exhibited varying abilities to accumulate heavy metals, with thorn spinning flower, desert brocade pheasant, red sand, and pig wool cabbage significantly enriching Cr and Ni,with bioconcentration factors all greater than 7.20. (4) Heavy metals such as Cd, As, Pb, Hg, Ag, Cr were found in the atmospheric dust and significantly associated with certain plants, with correlation coefficients ranging from 0.899 to 0.919. This study reveals that the distribution of heavy metals in atmospheric dust around copper tailings is affected by terrain, vegetation, distance, and meteorology conditions, resulting in uneven spatial distribution. Additionally, atmospheric dust serves as an important source of heavy metal accumulation in local plants. These findings provide a scientific basis for pollution prevention and control in mining areas.