The source and reference inventory of 239+240Pu in the soil of China

Publication Year
2018

Type

Journal Article
Abstract
This study used the large existing database on 137Cs reference inventories, according to the radioactivity ratio of 137Cs/239+240Pu (32.5, 137Cs radioactivity is corrected to 2005) in the Northern Hemisphere, and converted 137Cs reference inventories to the corresponding values for 239+240Pu. The 137Cs Reference Inventory Model for Mainland China (137Cs-RI MCM) had been used to establish an analogous, by using Kriging/Cokriging interpolation to simulate the spatial distribution of the Pu-RI in the soils across China. At present, the measured deposition inventories for 239+240Pu range from 7.3 to 546 Bq/m2and Pu-RI simulated values range from 3 to 812 Bq/m2. Maxima in the deposition inventory correlated well with those of the Pu-RI simulation, which suggested the 137Cs-RI MCM has potential for the simulation of the Pu-RI in the soils of the mainland of China. In-homogeneity in the atmospheric deposition of 137Cs and 239+240Pu however lead to deviations between the local Pu-RI simulation values and the measured 137Cs/239+240Pu radioactivity ratios present in Chinese soil cores. In order to better illustrate the feasibility of the 137Cs-RI MCM, this study compared theoretical wet deposition inventories of 239+240Pu with the corresponding Pu-RIs in 62 cities of China between latitudes 30-40°N, this showed that the theoretical calculations of Pu-RI or total deposition inventories and wet deposition inventories were reasonable.
Journal
China Environmental Science