CAO Liguo1, ZHANG Kexin2, XIAO Shun1
(1. School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China;
2. School of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China)
Abstract: The reconstruction of wet deposition history of plutonium isotopes is the important foundation for their tracer applications and safety assessments after nuclear accidents. On the basis of annual precipitation and 239+240Pu annual deposition flux data collected in Tokyo, this study investigated 239+240Pu annual wet deposition flux at the Loess Plateau of Northern Shaanxi via empirical equations. The results showed that 239+240Pu annual wet deposition flux was in the range of 0.0002-4.1167 Bq/m2 during 1957-2005 in the study area, and the cumulative wet deposition was estimated to be 14.08 Bq/m2. Compared the cumulative wet deposition at the Loess Plateau of Northern Shaanxi with the inventory in surrounding soil profiles, we deduced that the wet deposition to the dry deposition ratio in the study region is about 1. For temporal variation characteristics, the maximum annual deposition appeared in 1963 since of the large-scale atmospheric nuclear weapons testing in the early 1960s, and the 239+240Pu annual wet deposition flux presented an obvious decrease trend from 1964 to 2000. However, annual wet deposition flux of Pu isotopes showed an increase trend during 2001-2005 due to the particle suspension of Asian dusts.
Key words: Pu isotopes; atmospheric deposition; tracer technique; Loess Plateau of Northern Shaanxi
EARTH AND ENVIRONMENT Vol.46, No.5, Tot No.325, 2018, Page 417-422
