1241 / 2019-08-07 16:21:36

Seasonal variation of mercury and its isotopes in atmospheric particles at the coastal Zhongshan Station, Eastern Antarctia

15、冰冻圈科学 > 专题1：冰冻圈气候环境：过去、现在和未来

The first one year round mercury isotopes in atmospheric particulate mercury (PHg) and two years PHg concentrations from the coastal Zhongshan Station in eastern Antarctica were presented. Annual mean PHg concentration was 21.8±32.1 pg/m3, with the variation range between 0.9-195.6 pg/m3. Significant negative depletion of mass independent fractionation of odd isotopes (Odd-MIF, -0.38±0.17‰ and -0.31±0.18‰ for Δ199Hg andΔ201Hg, respectively) were detected. Photo- oxidation and reduction reactions dominated the isotopic fractionation of PHg with the ratio Δ199Hg/Δ201Hg of 1.26±1.98. Seasonal variations on PHg concentrations showed two peak periods in spring and summer, while lowest during winter. The spring high values were related to the oxidation of gaseous elemental mercury (GEM) with halogen radicals and the products include the reactive gaseous mercury (RGM) and PHg. Low fractionation values of Odd-MIF was accompanied by the highest PHg concentrations during spring, implying that in situ photoredox reactions were intensified. Summer peak values were mainly associated with the oxidation of GEM in the inland region and the subsequent transportation of RGM and PHg to the coastal regions by katabatic wind. The Odd-MIF values were weakened with the increase of the PHg concentration in summer, the intensified oxidation inland and the strengthened dynamic transportation was accountable.