[Pollution Characteristics, Source Analysis, and Health Risk Assessment of Heavy Metals of Soil in a Certain Coal Mining Area of Western Jiangxi Province].

Abstract

To explore the pollution characteristics, sources, and possible human health risks of soil heavy metals in a coal mine concentration area near western Jiangxi. The Nemerow index method was used to evaluate the characteristics of soil heavy metal pollution in the study area, the correlation of soil heavy metal pollution characteristics was described based on a self-organizing neural network （SOM）, the PMF model was used to trace the soil heavy metal pollution, and the exposure risk model established by EPA was used for health risk assessment. The results showed that the average content of heavy metals in the six soils ranged from 0.25 to 47.47 mg·kg^-1, which were all higher than the soil environmental background value in Jiangxi Province. Only the mean Cd content was higher than the risk screening value in GB15618-2018, and all heavy metal coefficients of variation were relatively high. The Nemerow pollution assessment indicated that the soil around the study area was severely polluted by heavy metals, especially As, Hg, and Cd as typical representatives. SOM-K clustering showed that Cu, Ni, and Cd had good correlation； Cu, As, and Hg had strong correlation； and Pb had obvious differences with other elements. The health risk assessment showed that the hand-mouth ingestion was the main exposure route of heavy metals in soil in the study area. Children in the study area had non-carcinogenic and carcinogenic health risks, while adults had carcinogenic health risks, and children were more exposed to health risks than adults. The comprehensive non-carcinogenic risk indexes （HI） for children and adults were 1.52E+00 and 2.41E-01, respectively. Additionally, the comprehensive carcinogenic risk index （TCR） for children and adults was 4.48E-05 and 2.85E-05, respectively. As was the main contribution index of health risk in the study area. The source analysis showed that the heavy metal sources in the soil of the study area were influenced by industrial dust fall sources, natural sources, coal pollution sources, transportation sources, and agricultural production sources, and their contribution rates were 25.62%, 22.00%, 17.88%, 17.84%, and 16.66%, respectively. It was mainly affected by human factors, which was consistent with the result of the high variation coefficient of soil heavy metals in the study area. The research results can provide theoretical basis for the prevention and control of heavy metal pollution in the soil of the study area.