著者

Mamoru Sato Kaori Matsuoka Tsugiko Takase Natsuko I. Kobayashi Hidetoshi Kikunaga Daisuke Takata Keitaro Tanoi Tsutomu Ohtsuki Shinnosuke Kusaba Katsuhiko Yamaguchi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-006, (Released:2019-01-18)

被引用文献数

8

---

We investigated the vertical 137Cs distribution in soil among five sod culture orchards with different soil textures over six years after 2011, when 137Cs fallout was released by the Fukushima Daiichi Nuclear Power Plant accident, to confirm the long-term 137Cs downward-migration into soil. At each orchard, soil cores were collected to a depth of 30 cm and subdivided into intervals of 3 to 9 cm. The 137Cs within the 3 cm of topsoil decreased from 84–94% during the first 7 months after deposition in 2011 to 41–75% in 2017. From 2012 onward, the vertical 137Cs profiles in the soils were explained by a two-component negative exponential model composed of a rapid and a slow component with a change of slope at a depth of 6 to 9 cm. It took 4 years after deposition to show a significant difference in the value of the average 137Cs migration distance (Md) among the orchards. The speed of 137Cs migration in the orchards during the 6 years after the accident year was 0.44 to 0.97 cm year−1 based on the Md. There was a significant positive correlation between Md and fine sand content in the 3 cm of topsoil between Md and the ratio of the total carbon content (TC) at a depth of 3 to 6 cm to that in the top 3 cm of soil. Furthermore, the percentage of exchangeable 137Cs (ex-137Cs) to 137Cs at 3 to 6 cm depth increased significantly in proportion to the ratio of TC at 3 to 6 cm depth to TC at 0 to 3 cm depth in soil collected in 2013. These findings indicate that one of the mobile forms of 137Cs was ex-137Cs combined with TC and that the fine sand content and TC influenced the 137Cs downward-migration in the 3 cm of topsoil in the orchard in which organic matter accumulated by sod culture.

著者

Toshinori ARAMAKI Ryohei SUGITA Atsushi HIROSE Natsuko I. KOBAYASHI Keitaro TANOI Tomoko M. NAKANISHI

出版者

公益社団法人 日本アイソトープ協会

雑誌

RADIOISOTOPES (ISSN:00338303)

巻号頁・発行日

vol.64, no.3, pp.169-176, 2015-03-15 (Released:2015-03-28)

参考文献数

23

被引用文献数

3 14

---

We performed an imaging analysis of 42K in Arabidopsis using real-time radioisotope imaging system(RRIS). First, we purified 42K from an 42Ar―42K generator. And then, we characterized RRIS performance by quantitatively determining 42K using standard series. As a result, the dynamic range for 42K was determined to be at least three orders of magnitude. Next, we evaluated the level of self-absorption in Arabidopsis organs by comparing the signal intensity detected using RRIS and the actual radioactivity detected by a gamma-counting method. There was no significant difference in detection efficiency between the thick bolt(stem) tissue and the thin leaf tissue. The reason for scarce self-absorption could be related to the relatively strong β ray emissions that have a maximum energy of 3525.4keV.