- 著者
- Keiko FUJIWARA Tomoyuki TAKAHASHI Tadatoshi KINOUCHI Satoshi FUKUTANI Yuki HATTORI Sentaro TAKAHASHI
- 出版者
- 日本保健物理学会
- 雑誌
- 保健物理 (ISSN:03676110)
- 巻号頁・発行日
- vol.50, no.3, pp.189-193, 2015 (Released:2016-02-06)
- 参考文献数
- 8
- 被引用文献数
- 1
Various radionuclides, including radioactive tellurium (Te), were released to the environment by the Fukushima nuclear power plant accident. The total amount of Te-127m released from the power plant was estimated to be 1.1 × 1015 Bq. The radioactive Te may have contributed to the internal radiation dose at the initial stage of the accident. However, data on the environmental behavior of radioactive Te are limited. In this study, therefore, the uptake of Te in plants was investigated. Radishes (Raphanus sativus var. sativus) were cultivated into a nutrient solution, grown for 20-30 days, and then their fine roots (taproots in the plant anatomy) and a part of fleshy roots (hypocotyls in the plant anatomy) were immersed for two hours into nutrient solutions with different Te and Cs concentrations. After soaking, plants were returned to the initial Te- and Cs-free nutrient solution for further maturation. ICP-MS measurements were made to assess concentrations of Te and Cs in the plants' leaves and fleshy roots (the fine roots were removed). Resulting differences among the individual plants were large. The leaf/fleshy root ratios of the concentration of Te and Cs were 0.09-1.14 and 1.59-5.00 on a fresh-matter basis, respectively. Both Te and Cs were absorbed by the radishes through the fine roots. There was a general tendency for Te to be retained in the fleshy roots, whereas Cs was mainly absorbed by the fine roots and then transferred to the leaves.
- 著者
- Yuki HATTORI Tadatoshi KINOUCHI Satoshi FUKUTANI Tomoyuki TAKAHASHI Keiko FUJIWARA Kayoko IWATA Sentaro TAKAHASHI
- 出版者
- 日本保健物理学会
- 雑誌
- 保健物理 (ISSN:03676110)
- 巻号頁・発行日
- vol.50, no.3, pp.194-196, 2015 (Released:2016-02-06)
- 参考文献数
- 11
- 被引用文献数
- 1
Three different types of soil were collected at each of three locations: a persimmon orchard, an ume (Prunus mume, so to speak, ‘a Japanese apricot’) orchard, and a paddy field located 50-55 km northwest from Fukushima Daiichi Nuclear Power Plant. The goal was to investigate the involvement of microbes inhabiting these soils on the behavior of 137Cs. The soils were sterilized with gamma ray irradiation for 30 hours (absorbed dose of 60 kGy) or with high-pressure steam (autoclave sterilization) at 121°C for 20 minutes. A radish cultivar (Raphanus sativus var. sativus) was then cultivated in those soils for 45 days, and the harvested taproots and leaves were testing using a Ge semiconductor detector for concentration of 137Cs. The result showed that the concentration of 137Cs in radishes cultivated in the sterilized soils with autoclave sterilization or gamma ray irradiation were significantly higher than in those cultivated in the unsterilized soils. An increase in the plant available 137Cs could be caused by NH4+ arisen from the multiple effects of the structural change of the soil, decomposition of organic matter, and/or extinction of the microbes by sterilization.
- 著者
- Hidehito NAKAMURA Yoshiyuki SHIRAKAWA Hisashi KITAMURA Nobuhiro SATO Sentaro TAKAHASHI
- 出版者
- 一般社団法人日本保健物理学会
- 雑誌
- 保健物理 (ISSN:03676110)
- 巻号頁・発行日
- vol.49, no.2, pp.98-101, 2014 (Released:2015-05-21)
- 参考文献数
- 25
- 被引用文献数
- 7 9
The enormous area of damage to Japan's Fukushima Daiichi nuclear power plant requires radiation detectors with robust base substrates to monitor high-dose-rate environmental radiation with long-term stability. Undoped aromatic ring polymers have considerable potential as base substrates in radiation detection. Here, we characterise polycarbonate (PC), which has excellent transparency, shock, radiation, and weather resistance, heat tolerance, and anti-abrasion qualities. It has a density of 1.20 g/cm3, an excitation maximum of 310 nm, and short-wavelength emission with a maximum at 350-nm. By taking into account its emission spectrum, we determined an effective refractive index of 1.64. PC has a light yield that is 0.67 times that of undoped poly (ethylene terephthalate). These results reveal that readily available PC is an effective base substrate for use in large-area radiation detectors for the nuclear power plant recovery process.