DISTRIBUTION OF RADIOCESIUM IN BLACK PINE TREE FORESTS IN ROKKASHO, AOMORI, JAPAN. Issue 13 (9th September 2022)

• Record Type: Journal Article
• Authors: Ohtsuka, Yoshihito; Hasegawa, Hidenao; Ayabe, Yoshiko; Hisamatsu, Shun'ichi
• Is Part Of: Radiation protection dosimetry. Volume 198:Issue 13/15(2022)
• Page Start: 1131
• Page End: 1136
• Publication Date: 2022-09-09
• Subjects: Radiation dosimetry -- Periodicals; Radiation -- Safety measures -- Periodicals; 363.1799
• DOI: 10.1093/rpd/ncac076
• Languages: English
• ISSNs: 0144-8420

Abstract

Abstract: Since the Fukushima Dai-ichi Nuclear Power Plant (FDNNP) accident in 2011, 134 Cs had been detected in atmospheric deposition samples collected in Rokkasho and Aomori in Japan, located ~400-km north of the FDNNP, during March 2011–May 2015. To study the distribution of radiocesium ( 134, 137 Cs) in a Japanese black pine tree forest, we measured the activity concentration of 134, 137 Cs in whole black pine trees, including roots collected during 2017–19 along with soil samples in 2015 and 2017–19. The results show that most of the deposited 134 Cs was retained in the forest floor in 2015, with depth distribution different from that of the weapon testing fallout. Proportions of the weapon fallout 137 Cs in trunks, branches, needles and roots were 44, 17, 13 and 26%, respectively, indicating that >50% of 137 Cs in above-ground part existed in the trunks. The total inventories of 134 Cs and 137 Cs in the forest were estimated to be 8.9 and 2.5·10 3 Bq m −2, respectively, and ~4.8% of 137 Cs inventory was originated from the accident. Inventory of 134 Cs in the forest—including the black pine trees—was 1.6 times larger than cumulative deposition outside of the forest due to the canopy effect.