Spatial Distributions, Pollution Assessment, and Qualified Source Apportionment of Soil Heavy Metals in a Typical Mineral Mining City in China

Li Hua,Xiuli Tan,Xue Yang,Yajun Liu,Yong Yang

doi:10.3390/su10093115

Abstract

Daye is a city in China known for its rich mineral resources, with a history of metal mining and smelting that dates back more than 3000 years. To analyze the spatial distribution patterns, ecological risk, and sources of heavy metals (Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn) in soils, 213 topsoil samples were collected in the main urban area of Daye in September 2016. The mean concentrations of Cd, Cu, Pb, and Zn were higher than the corresponding background values, with the mean concentration of Cd being almost seven times its background value. Spatially, the high concentrations of Cd, Mn, Pb, and Zn were mainly concentrated in the southeastern part of the region due to nonferrous metal mining and smelting. However, the high concentrations of Co and Cu were concentrated in the central part of the study area, resulted from copper mining and smelting. The data of the geoaccumulation index showed that the contamination levels ranged from no pollution (Co, Cr, Mn, and Ni) to heavy contamination (Cd, Cu, and Pb). Ecological risk assessment showed that Cd posed a high, serious, and even severe ecological risk in 53.78% of the area of Daye. According to the results of the principal component analysis, mineral exploitation and smelting involving a variety of minerals (ES_M), mining exploitation, and smelting of copper ore (ES_C), and natural sources are the three main sources of heavy metals in these soils. Furthermore, the absolute principal component scores showed that 69.21% and 23.17% of the heavy metal concentrations were ascribed to ES_M and ES_C, respectively.

Highlights

With the increases in intense urbanization, industrialization, and human population, soil heavy metal pollution has been significant over the past several decades because of the toxicity and undegradability of these pollutants [1,2,3,4]
The mean concentrations of Co and Mn were less than their background values, their PbB values exceeded 30%, indicating that part of the study area was polluted by these two heavy metals
The present study identified the pollutant characteristics and sources of heavy metals in soils of Daye, China

Summary

Introduction

With the increases in intense urbanization, industrialization, and human population, soil heavy metal pollution has been significant over the past several decades because of the toxicity and undegradability of these pollutants [1,2,3,4]. Existing studies have shown that heavy metal soil pollution is related to mining activities, including mining, smelting, and transportation. Liang et al reported that 26.05% of the heavy metals in soil were a result of mining activities in a typical coal mining city, Lianyuan, in the Hunan province of China [8]. Xu et al investigated paddy soils from lead-zinc mining areas in the Guangdong province, China [10]. Their results indicated that the paddy soils were heavily contaminated with Cd, Pb, and Zn in amounts that exceeded the corresponding soil quality standard values and background values

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Results

Conclusion