1.Kunming General Survey of Natural Resources Center, China Geological Survey、Technology Innovation Center for Natural Ecosystem Carbon Sink, Ministry of Natural Resources;2.School of Water Resources and Environment, China University of Geosciences (Beijing);3.College of Ecology and Environment, Yunnan University
Abstract: This paper is result of geological survey engineering. 【Objective】The study area is located in an important coal and agricultural production area in eastern Yunnan Province. It is of great practical significance to understand the spatial distribution characteristics, potential ecological risks and pollution sources of heavy metals in soil of coal mining area for ecological environment protection and ensure agricultural security.【Methods】497 soil samples collected in June 2017 in a typical coal mining area based on the grid placement method, and Soil pH, SOM, As, Cd, Cr, Cu, Hg, Ni, Pb and Zn were analyzed. Pollution load index method and potential ecological risk index method were used to evaluate heavy metal pollution status and potential ecological risk. The potential sources of heavy metals were analyzed by principal component analysis and positive definite matrix factor analysis.【Results】The mean of soil pH is 5.39, mainly acidic, and the mean of SOM content is 12.00 times higher than the background value for soils in Yunnan Province. The mean and median of Cr, Cu, Cd, Ni, Zn and Hg are all higher than the soil background value of Yunnan Province, the majority of sampling points Cd, Cu, Cr, Ni content exceeds the risk screening value, accounted for 94.97%, 93.96%, 91.35%, 79.28%, and a small number of sampling points exceeds the control values for As and Cd, accounting for 0.20% and 1.41% respectively. The results of the Pollution Load Index method of evaluation show that the study area as a whole shows slight pollution. The results of the evaluation of the potential ecological risk index method show that the study area as a whole presents a medium risk. The results of the principal component analysis and the PMF model analysis show that soil heavy metals in the study area are mainly derived from the geological background, followed by agricultural activities and atmospheric deposition.【Conclusion】 The potential ecological risk of Cd and Hg in the soil of the coal mining area is high, and the soil heavy metals mainly derived from the geological background, followed by agricultural activities and atmospheric deposition. It is suggested to strengthen the monitoring and management of related polluted land, reduce the unreasonable application of farmyard manure, and strengthen the supervision of pollution from coal industry activities.