Source apportionment of mercury in surface soils near the Wuda coal fire area in Inner Mongolia, China

The Wuda coalfield, Inner Mongolia, China, has been suffering from serious coal fire disaster for more than half a century. In the past decade, central and local governments have carried out many fire-fighting projects to put fires, but fires still sporadically occur in coalfield. Previous studies showed that could release large amounts of mercury (Hg) into environment. Meanwhile, rapid industrial development recent years area also discharged certain amount Hg. Identification quantification Hg emitted sources is critical formulate appropriate environmental policies. This study determined isotope compositions different types coals surface soils with distances area, an aim anchoring potential soils. results had moderately negative δ202Hg (−2.02∼-1.21‰) slightly Δ199Hg (−0.14–0.00‰), while generally positive (−1.97∼-0.26‰) (−0.07–0.04‰) distinct ranges among sampling sites. According characteristic sources, we concluded mainly sourced cement plants were important contamination source area.