Transfer Factor of 137Cs in Several Fruit Tree Species Planted After Radioactive Fallout in Orchard in Fukushima Prefecture and the Effect of Topsoil Management on 137Cs Concentration in Persimmon Fruits

Sachie Horii; 堀井幸江; Atsushi Kuwana; 桑名篤; Minako Yuda; 湯田美菜子; Kiyoshi Hiraoka; 平岡潔志; Haruna Minami; 南春菜; Kaori Matsuoka; 松岡かおり; Shinnosuke Kusaba; 草塲新之助

doi:10.3769/radioisotopes.69.93

福島県においてフォールアウト後に樹園地に植栽した数種の果樹の移行係数とカキ果実の¹³⁷Cs濃度に及ぼす表土処理方法の影響Transfer Factor of ¹³⁷Cs in Several Fruit Tree Species Planted After Radioactive Fallout in Orchard in Fukushima Prefecture and the Effect of Topsoil Management on ¹³⁷Cs Concentration in Persimmon Fruits

堀井幸江¹，桑名篤²^,*1，湯田美菜子³，平岡潔志⁴，南春菜²，松岡かおり¹，草塲新之助¹Sachie Horii¹, Atsushi Kuwana²^,*1, Minako Yuda³, Kiyoshi Hiraoka⁴, Haruna Minami², Kaori Matsuoka¹, Shinnosuke Kusaba¹

¹ 国立研究開発法人農業・食品産業技術総合研究機構果樹茶業研究部門Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization

² 福島県農業総合センター果樹研究所Institute of Fruit Tree Research Center, Fukushima Agricultural Technology Centre

³ 福島県農業総合センターFukushima Agricultural Technology Centre

⁴ 国立研究開発法人農業・食品産業技術総合研究機構西日本農業研究センターWestern Region Agricultural Research Center, National Agriculture and Food Research Organization

^*1

現所属：福島県環境保全農業課Present address: Fukushima Prefectural Government

受付日：2019年7月5日Received: July 5, 2019

受理日：2019年10月25日Accepted: October 25, 2019

発行日：2020年3月15日Published: March 15, 2020

福島県内の樹園地において，東京電力福島第一原子力発電所の事故1～2年後に植栽したクリ，温州ミカン，カキの¹³⁷Csの移行係数の経年変化を3～5年間調査した。調査年によってばらつきは認められたが，移行係数はどの樹種においても10⁻⁴～10⁻³の範囲であった。カキ‘蜂屋’と‘平核無’の移行係数を比較したところ，‘蜂屋’は‘平核無’よりも高い傾向がみられた。‘蜂屋’で表土処理方法（耕転，表土剥ぎおよび表土戻し）を比較したところ，表土剥ぎ区の土壌の¹³⁷Cs濃度は他の2区よりも低かったが果実の¹³⁷Cs濃度に有意な差はみられなかった。

We conducted a 3- to 5-year study of the transfer factors (TF) of ¹³⁷Cs in Japanese chestnut, satsuma mandarin and Japanese persimmon trees planted 1 to 2 years after the Fukushima Dai-ichi Nuclear Power Plant accident. The TFs of these fruit trees were on the order of 10⁻⁴ and 10⁻³ across the several years and showed annual variations. Comparison of the TFs between two Japanese persimmon cultivars, ‘Hachiya’ and ‘Hiratanenashi,’ seemed to be higher TFs values of the fruit and leaves in the former than in the latter cultivar. We further investigated the effect of topsoil management (plowing, topsoil removal, and topsoil return) on ¹³⁷Cs concentration in ‘Hachiya’ fruit and the planted soil. The soil ¹³⁷Cs concentration in the topsoil removal treatment was lower than that in the plowing and topsoil return treatments, but the topsoil management had no effect on the ¹³⁷Cs concentration of ‘Hachiya’ fruit in this experiment.

Key words: Fukushima Dai-ichi Nuclear Power Plant Accident; transfer factor of caesium-137; topsoil management; fruit tree

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