[Concentrations and pollution assessment of mercury in farmland soil of Xinqiao Mining Area of Tongling, Anhui, China.]

To investigate the effects of mining activities on mercury (Hg) enrichment in farmland soil, soil samples were collected from four villages (Xinjian Village, Yehu Village, Xinhu Village and Hucheng Village) in the vicinity of Xinqiao Mining Area, Tongling. Hg concentration was measured by atomic fluorescence spectrophotometer. The geo-accumulation index was used to evaluate the Hg pollution level of the soils. The results showed that average concentration of total Hg in farmland soil was (0.137±0.078) mg·kg-1, which exceeded the background value of soil Hg in Tongling area. The average concentration of Hg in four villages followed the order of Xinjian Village (0.221 mg·kg-1)>Xinhu Village (0.118 mg·kg-1)>Yehu Village(0.115 mg·kg-1)>Hucheng Village (0.096 mg·kg-1). Moreover, the average Hg concentration of different forms in Xinjian Village followed the order of residue (0.036 mg·kg-1) > alkali soluble (0.031 mg·kg-1) > hydrogen peroxide soluble (0.022 mg·kg-1)> acid soluble (0.020 mg·kg-1)> water soluble (0.012 mg·kg-1). The distance from the mining area was the main factor affecting the distribution of soil Hg concentration in farmlands. The contaminated Xinqiao River, to some degree, had exa-cerbated soil Hg pollution. Soil organic matter affected the accumulation and transformation of total Hg and hydrogen peroxide Hg in the farmlands. The order of the geo-accumulation index followed as Xinjian Village(1.559) >Xinhu Village(0.654) >Yehu Village(0.616) >Hucheng Village(0.356). The pollution level of farmland soil in Xinjian Village belonged to middle level of Hg pollution,which deserved more attention.