Depth distribution of239,240Pu and137Cs in soils of South Korea

Concentration and characterization of plutonium in soils of Hubei in central China

“…The vertical profiles are similar to those observed in Japan by Mahara and Miyahara (1984) and in Korea by Lee et al (1996), which are in the same latitudinal band at 30-40 N. These authors found that the Pu accumulated in the first 10 cm layer was more than 85% of the total, which is similar to, but lower than our results. Lee et al (1996) obtained two types of depth profile for their Korean soils: in some undisturbed soils the concentration of Pu decreased nearly exponentially with increasing depth, while in other soils the maximum 239þ240 Pu concentration was not found on the surface, but rather at 2-4 cm depth. Similarly, the DK profile shows a maximum 239þ240 Pu concentration at 2-4 cm, with the concentration decreasing exponentially below this depth.…”

“…This can be explained by downward percolation through the soil with rainwater and/or by the loss of fine particle fractions that absorb relatively higher amounts of these nuclides and/or by dilution of the upper layer(s) with humic material deposited in the post atmospheric testing era. It is noteworthy that the organic matter distributions for soil from site DK are very similar to those recorded by Lee et al (1996) for soil from Jungsun, South Korea. Plutonium is known to form complexes with humic substances (Lee et al, 1997), and at both sites the organic matter content for the 0-2 cm depth increment is 11%.…”

Characterization of Pu concentration and its isotopic composition in soils of Gansu in northwestern China

“…The contribution of the top 10 cm layers of surface soils to total inventory was only 17%, while the contribution of deeper layers (10-23 cm) was as high as 83%. The vertical distributions of 239þ240 Pu observed in the Lanzhou soil core differ from those observed in Korea and Japan in the same latitude bands of 35-40 N. In South Korea, Lee et al (1996) observed two types of depth profiles: (1) the concentrations of 239þ240 Pu decrease nearly exponentially with increasing depth; and (2) the maximum concentration of 239þ240 Pu was found not in the top layer but in the second layer of 2-4 cm depth, and this was attributed to downward percolation through the soil due to rainwater or out-flowing loss of the fine particle fractions adsorbing larger amounts of Pu. In Japan, Yamamoto et al (1980) observed similar depth profiles in soils from Fukui Prefecture.…”

“…Apparently, the downward migration rate of Pu isotopes in Lanzhou soil is much faster than that observed in South Korea and Japan. The mobility of Pu isotopes in the soil system depends on the physical and chemical properties of the soil, the oxidation state and ionic size of Pu isotopes, and the climate (Lee et al, 1996). The studied soil core in Lanzhou mainly consisted of loess, i.e.…”

Using 239+240Pu atmospheric deposition and a simplified mass-balance model to re-estimate the soil erosion rate: a case study of Liaodong Bay in China

“…The 239?240 Pu results from the reference sites are shown in Fig. 3 and Table 1 [32]. Typically, 70-80 % of the inventory was found in the top 10 cm at both sites, with about 35 and 55 % concentrated in the top 5 cm layer of DL-01and DL-03 respectively.…”