Dry and wet atmospheric deposition fluxes of elements in the Plain area of Beijing Municipality, China

From November 2005 to November 2006, 39 samples of dry and wet atmospheric deposition were collected from ten sites in the Plain area of Beijing Municipality. The samples were filtered and divided into soluble and insoluble fractions and analyzed for K, Na，Ca, Mg, Cd, Hg, Pb, As, B, Mo, Mn, Zn, Cu, Cr and Ni contents. The annual deposition fluxes of the 15 elements were calculated respectively. Of these elements, the average deposition fluxes of the harmful heavy metal elements Cd, Hg, Pb and As are 2.36, 0.24, 219.95 and 29.00 g/hm2·a respectively. Comparison of the deposition fluxes of the heavy metal elements shows that: the annual loadings of Cd and Hg in the atmosphere in the study area are far lower than those in the Chengdu economic area, Sichuan; the Cd and Hg pollution in the atmosphere is weaker than in southern China; and the annual loadings of As and Pb have little difference as compared with the Chengdu economic area. Correlation analysis of the deposition flux of elements in the atmosphere and that in soils at the same site in the study area shows that the element deposition fluxes are not the main input way of the elements in soils in the farmland ecosystem, and the elements in atmospheric fallouts came mainly from distal sources.