Radiocarbon concentration in modern tree rings from Fukushima, Japan. (August 2015)

• Record Type: Journal Article
• Authors: Xu, Sheng; Cook, Gordon T.; Cresswell, Alan J.; Dunbar, Elaine; Freeman, Stewart P.H.T.; Hastie, Helen; Hou, Xiaolin; Jacobsson, Piotr; Naysmith, Philip; Sanderson, David C.W.
• Is Part Of: Journal of environmental radioactivity. Volume 146(2015:Aug.)
• Page Start: 67
• Page End: 72
• Publication Date: 2015-08
• Subjects: Cryptomeria japonica tree ring -- Cellulose 14C -- Fossil fuel -- Traffic effect -- Fukushima nuclear accident; 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.2015.04.004
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: A 30-year-old Japanese cedar ( Cryptomeria japonica ), collected from Iwaki, Fukushima in 2014, was analyzed for the long-lived radionuclide 14 C. Values of Δ 14 C varied from 211.7‰ in 1984 to 16.9‰ in 2013. The temporal Δ 14 C variation can be described as an exponential decline, indistinguishable from the general Northern Hemisphere Zone 2 (NH Zone 2) values in the atmosphere, until at least 1994. Values of Δ 14 C for 1999 and 2004 are slightly depleted compared with NH Zone 2 values, while from 1999 to 2013 the data suggest a clear depletion with a 2–8 ppmV additional CO2 contribution from a 14 C-free (i.e. fossil carbon) source. This change coincides with local traffic increases since two nearby expressways were opened in the 1990's. In addition, the small but visible 14 C pulse observed in the 2011 tree-ring might be caused by release from the damaged reactors during the Fukushima nuclear accident. Highlights: We measured 14 C activity in modern tree rings in a 30-year-old Japanese cedar from Fukushima. The temporal Δ 14 C variation is ascribed as an exponential decline. The local traffic increases caused a clear 14 C deletion since 1990's. Small 14 C might be released during the Fukushima nuclear accident.