Change in the chemical form of 137Cs with age in needles of Japanese cedar. (March 2020)

• Record Type: Journal Article
• Authors: Hara, Tatsuya; Takenaka, Chisato; Tomioka, Rie
• Is Part Of: Journal of environmental radioactivity. Volume 213(2020)
• Publication Date: 2020-03
• Subjects: Radiocesium -- Sugi -- Needle -- Aging -- Chemical form; Radioactivity -- Periodicals; Radiation, Background -- Periodicals; Radioecology -- Periodicals; Radioactive pollution -- Periodicals; Environmental Pollutants -- Periodicals; Radioactive Pollutants -- Periodicals; Radioactivity -- Periodicals; Radioécologie -- Périodiques; Pollution radioactive -- Périodiques; Fond de rayonnement -- Périodiques; 539.752
• DOI: 10.1016/j.jenvrad.2019.106137
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: Radiocesium ( 137 Cs) derived from the accident of Fukushima Dai-ichi Nuclear Power Plant remains in forests. Although a large proportion of the 137 Cs in forests has been transferred to soils, the rates of transfer to soils depend on the chemical form of 137 Cs, which determines the mobility of 137 Cs in plant tissues and subsequently during decomposition of leaf litter. In order to understand the dynamics of 137 Cs in Sugi (Japanese cedar, Cryptomeria japonica ) forests, we identified the chemical forms, such as water soluble, ion-exchangeable, and residual of 137 Cs, 133 Cs, K, and Rb in needle-bearing Sugi branches of different ages across several years. Compared with the results for K and Rb, Cs ( 133 Cs + 137 Cs) tended to change from a water-soluble form to an immobilized form with aging of needle-bearing branch segments. In addition, it was observed that a larger proportion of the immobilized Cs were accumulated in the green outer portions of the stems through aging. Highlights: We identified the chemical forms of 137 Cs, 133 Cs, K, and Rb in needle-bearing Sugi branches of different ages. Cs ( 137 Cs and 133 Cs) in Sugi needles tended to change from a water-soluble form to an immobilized form with aging. A larger proportion of the immobilized Cs were accumulated in the green outer portions of the stems.