Soil mercury pollution caused by typical anthropogenic sources in China: Evidence from stable mercury isotope measurement and receptor model analysis

Abstract Human activities have caused serious soil mercury (Hg) pollution in industrial areas worldwide. Abatement of soil Hg pollution requires knowledge of Hg sources and transport pathways across various environmental media. In this study, four areas containing typical anthropogenic Hg emissions in China were selected to evaluate soil Hg pollution. Results showed that soil Hg contents were significantly elevated in areas of Hg mining, gold mining, and zinc smelting, but only slightly elevated in an area of coal-fired power plant, with averages of 44.0, 1.17, 0.73, and 0.14 μg g−1 (dry weight) in these four areas, respectively. The average percentage contributions from these anthropogenic sources to soil Hg in surrounding areas were estimated to be 92.2 ± 9.70% from Hg mining (among which 77.6 ± 12.0% from unroasted Hg ore and 14.6 ± 7.50% from Hg calcine), 63.5 ± 0.83% from the zinc smelting, 41.6 ± 1.90% from gold mining, and 21.1 ± 3.58% from coal-fired power plant. Atmospheric deposition was speculated to be the main pathway for soil Hg contamination, but mercury mining area contained significant runoff accumulation. Speciation and concentration of Hg in emission gas are crucial factors for Hg pollution in surrounding soils, because of short residence time of Hg2+/Hgp in the atmosphere. The results obtained in this study can provide scientific advices for risk assessment and soil remediation of Hg in China and other regions with similar industries.