||Effective half-lives of radiocesium in different Japanese tree species
Tagami, Keiko ,
Uchida, ShigeoIshii, Nobuyoshi
Radiocesium decreasing rates in trees have been reported after nuclear accidents; the rate is expressed as effective half-life (Teff) and we recently reported the value for persimmon trees (Tagami and Uchida, J. Environ. Radioact. 141, 8-13, 2015). It is important to compare these values observed after the Fukushima and Chernobyl accidents to understand the difference/similarity of radiocesium fate in the environments and radiation effects to human and biota from these accidents. Therefore, we did literature survey and field observation to compare Teff in trees. In order to reduce the climate effect, we selected 137Cs data in Japanese black pine and tea tree leaves, and Citrus unshiu fruits collected in Japan from 1985 to 2013 using the environmental radiation database (Nuclear Regulation Authority, http://search.kankyo-hoshano.go.jp/servlet/search.top, in Japanese, 2016). From the database, we found direct deposition effect from the Chernobyl accident (1986-1988) and the Fukushima accident (2011-2013). We also measured 137Cs concentrations in Citrus natsudaidai for comparison from September 2011 to March 2014 at our institute campus in Chiba City, Japan.
The 2nd international conference on radioecological concentration processes