Spatial distribution and source analysis of soil heavy metal pollution in Wucaiwan Mining Area based on PMF model

The soil around Wucaiwan Mining Area in Jundong Coalfield, Xinjiang is studied, collecting the 100 soil samples are taken from soil surface.The assessment of the ecological risks of six heavy metals in soil by using soil accumulation index, potential ecological risk index and comprehensive risk index.The positive definite matrix factor analysis model(PMF) is used to analyze the sources and contribution rates of the six heavy metals in the soil.The research results show that the mean contents of heavy metals Zn, Cu, Cr, Pb, Hg and As in the soil are 69.60 mg/kg, 23.42 mg/kg, 59.15 mg/kg, 22.37 mg/kg, 0.033 mg/kg and 6.71 mg/kg.The orders of the concentrations of six heavy metals is Zn> Cr> Cu> Pb> As> Hg, the six heavy metals are not exceeded the national standards.Zn, Pb, Hg and As exceed the background values in Xinjiang, which are 1.01, 1.20, 1.15 and 1.94 times.The calculation of the geo-accumulation index results can be seen that Zn, Cu, Cr, Hg and As are slightly polluted or unpolluted, while Pb is in the medium-high polluted state.The results of potential ecological risk index show that heavy metals Zn, Cu, Cr, Hg and As are not polluted, while Pb is in a state of strong risk.The results of the comprehensive risk index show that the comprehensive risk index of Hg element is 7 870.59, which is in the state of extremely high risk, while the potential risk level of the other five heavy metals is low to slight risk.The positive definite matrix factor analysis model(PMF) analyzes that the pollution sources of 6 kinds of heavy metal elements in the soil are natural factor, industrial pollution, traffic emission, coal combustion, atmospheric dust fall and anthropogenic industrial activities, contribution rates of these pollution sources 20%, 14%, 14%, 22%, 20%, 10%.The research results will provide the scientific basis and technical support for monitoring and early warning of the arid region soil contamination.