Excess polonium-210 in the coastal atmosphere originating from marine biogenic material
- 海洋环境－已发表论文 
The depositional fluxes of atmospheric polonium-210 were measured at one site in Xiamen from August 2001 to March 2002. With predominant marine air mass, the depositional fluxes of atmospheric polonium-210 ranged from 0.01 to 0.09 Bq/(m(2) . d), with an average of 0.04 Bq/ (m(2) . d). The seasonal pattern showed elevated polonium-210 fluxes in summer and autumn rather than in winter. Atmospheric depositional fluxes of polonium-210 showed a good correlation with beryllium-7 (r(2) = 0.85) and lead-210 fluxes (r(2) = 0.71), indicating their similar removal mechanism from atmosphere. The relationship between the polonium-210 depositional fluxes and the precipitation amount demonstrated that the precipitation dominates the polonium-210 removal from the atmosphere. The observed high activity ratios of polonium-210 to lead-210 indicated the occurrence of excess polonium-210 in coastal atmosphere, which may originate from marine surface waters either by indirect ( foam), or more likely, direct (air-sea exchange) input of marine biogenic material into the atmosphere. This source is even more important than the in situ decay of lead-210.