Objective To investigate the pollution characteristics, pollution sources, and health risks of metal and metalloid in farmland soil in coal mine areas of Shanxi Province, China.

Methods The contents of metal and metalloid were determined for the farmland soil samples from a coal mine area of Shanxi province, and the characteristics of metal and metalloid pollution were analyzed in soil samples. The principal component analysis/absolute principal component score receptor model (PCA/APCS) was used to investigate pollution sources, and the health risk assessment index system was used to analyze the health risks of residents around the mine area.

Results The result showed that the mass concentrations of Zn, Cu, Cr, and As in the polluted area were significantly higher than those in the control area, and the mass concentration of As was 3.4-4.3 times of the risk control value for metalloids. The study area had a Nemerow index of 4.34, which showed the presence of severe combined pollution of metal and metalloid in soil. The pollution load index was 1.59, indicating a mild level of metal and metalloid pollution load in soil. The potential ecological risk index of the study area was 32.89, suggesting a mild risk of soil ecology. Source apportionment showed that the heavy metals of Zn, Ni, and Cu in soil were affected by human activities such as coal mining, coal transportation and agricultural activities, and As and Cr were mainly affected by nature activities. The non-carcinogenic risk index did not exceed the threshold value of 1, indicating that metal and metalloid pollution posed little non-carcinogenic risk to human health. The carcinogenic risk index of Ni, Cr, and As ranged from 10^-6 to 10^-4, indicating that these metal and metalloid posed a certain carcinogenic risk to human health, which was within an acceptable range.

Conclusion There is a significant difference in the distribution of metal and metalloid in soil of polluted coal mine area, and combined metal and metalloid pollution should be taken seriously. Although the health risk caused by soil metal and metalloid pollution does not exceed the threshold, the prevention and control of soil pollution should be performed actively. The health risk of soil metal and metalloid should be closely monitored to strengthen early warning.