[Contamination Characteristics and Source Apportionment of Heavy Metals in Soil around the Agricultural Land in Coal...

In order to explore the characteristics and sources of heavy metal pollution in the surrounding soil of a coal mine concentration area in Pingxiang, Jiangxi Province, based on the test results of six heavy metal indicators (Cd, Hg, Pb, Cu, Ni, and Zn) and pH values of 127 sampling sites, the geo-accumulation index and Nemerow integrated pollution index methods were used to compare and evaluate the pollution characteristics of soil heavy metals. On the basis of correlation analysis, APCS-MLR and PMF models were used to quantitatively analyze the sources and contributions of soil heavy metal pollution. The results showed that the average content of heavy metals in six types of soils was higher than the soil environment background value in Jiangxi Province. There were five types of soil heavy metals, Cd, Hg, Cu, Ni, and Zn, with contents exceeding the risk screening value in GB 15618-2018, and some samples had Cd content exceeding the control value of GB 15618-2018. The spatial distribution characteristics of Pb, Cu, and Ni were highly similar. Cd was highly enriched in the downstream area of coal mine concentration. The spatial distribution and correlation coefficient of Hg indicated that its source may have been different from other indicators. The high-value area of Zn was significantly smaller than that of other indicators. The pollution assessment showed that the overall soil in the study area was moderately polluted or above, with Cd, Hg, and Ni as the main pollution indicators. The heavy metal pollution in the coal gangue accumulation area was more severe than in other surrounding areas. The APCS-MLR model analyzed two known sources and one unknown source, with contribution rates of 65.69% from a mixture of industrial dust, natural causes, transportation, and coal mine pollution; 8.02% from agricultural activities; and 26.29% from unknown sources. The PMF model identified five pollution sources, agricultural activity sources, industrial dust sources, coal mine pollution sources, transportation sources, and naturally occurring sources, with corresponding contribution rates of 23.61%, 16.84%, 22.74%, 25.85%, and 10.96%, respectively. The source analysis results were consistent with the actual situation in the study area, which can provide theoretical support for the prevention, control, and remediation of soil heavy metal pollution in the study area.