Changes in the distribution of radiocesium in the wood of Japanese cedar trees from 2011 to 2013. (September 2016)

• Record Type: Journal Article
• Authors: Ogawa, Hideki; Hirano, Yurika; Igei, Shigemitsu; Yokota, Kahori; Arai, Shio; Ito, Hirohisa; Kumata, Atsushi; Yoshida, Hirohisa
• Is Part Of: Journal of environmental radioactivity. Volume 161(2016:Nov.)
• Page Start: 51
• Page End: 57
• Publication Date: 2016-09
• Subjects: Fukushima Dai-ichi Nuclear Power Plant accident -- Radiocesium -- Japanese cedar tree -- Tree contamination -- Wood; 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.2015.12.021
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: The changes in the distribution of 137 Cs in the wood of Japanese cedar ( Cryptomeria japonica ) trunks within three years after the Fukushima Dai-ichi Nuclear Power Plant (FDNP) accident in 2011 were investigated. Thirteen trees were felled to collect samples at 6 forests in 2 regions of the Fukushima prefecture. The radial distribution of 137 Cs in the wood was measured at different heights. Profiles of 137 Cs distribution in the wood changed considerably from 2011 to 2013, and the process of 137 Cs distribution change in the wood was clarified. From 2011 to 2012, the active transportation from sapwood to heartwood and the radial diffusion in heartwood proceeded quickly, and the radial 137 Cs distribution differed according to the vertical positon of trees. From 2012 to 2013, the vertical diffusion of 137 Cs from the treetop to the ground, probably caused by the gradient of 137 Cs concentration in the trunk, was observed. Eventually, the radial 137 Cs distributions were nearly identical at any vertical positions in 2013. Our results suggested that the active transportation from sapwood to heartwood and the vertical and radial diffusion in heartwood proceeded according to the vertical position of the tree and 137 Cs distribution in the wood approached the equilibrium state within three years after the accident. Graphical abstract: Highlights: Profiles of 137 Cs distribution in the wood of Japanese cedar trees changed considerably from 2011 to 2013. The radial 137 Cs distribution profiles differed depending on the vertical position on the tree in 2012. The 137 Cs distribution in heartwood became uniform in 2013 by the vertical and radial diffusion of 137 Cs.