抄録
It is important to understand the distribution and fate of Pu in lakes due to their radioation threat and high chemical toxicity, since many lakes are the source of drinking-water.Moreover, studies indicated that Pu is useful for establishing deposition chronology of lakes, which has been commonly studied using 210Pb and 137Cs. However, differing from the analysis of 137Cs, samples must be destroyed during the analysis of Pu. Thus, a precise method with small sample size is always preferable for the determination of Pu in lake sediments.
We report a simple and accurate Pu analytical method using ICP-SF-MS combined with chromatographic separation and purification for the studies of recent aquatic sedimentation. An anion-exchange resin (AG MP-1M) was used to purify Pu isotopes.The chemical yield was ca. 64 %. For the analysis of IAEA-368, both Pu activity of 31.6 mBq/g IAEA-368, both Pu activity of 31.6 mBq/g and 240Pu/239Pu atom ratio of 0.033 were comparable to other Pu analytical schemes. For SRM 4354, Pu activity of 3.90 mBq/g For SRM 4354, Pu activity of 3.90 mBq/g agrees well with the certified value. However, the mean 240Pu/239Pu atom ratio of the mean 240Pu/239Pu atom ratio of 0.144 +/-0.004 was lower than those reported by other labortories.Considering the fact that those reported values were different from each other, our results suggest thath this material may be isotopically inhomogeneous. The developed analytical method was applied to analyze Pu isotopes in sediment samples of Lake Poyang, East China. 2 sediment samples of Lake Poyang, East China. 240Pu/ samples of Lake Poyang, East China. 240Pu/239Pu atom ratios for these samples ramged from 0.185 to 0.192 with a mean value of 0.187, indicating no plutonium pollution originated from non-global fallout.
