Control of radiocesium recontamination by plant removal along a decontaminated riverside in Fukushima, Japan

JOURNAL OF ENVIRONMENTAL MANAGEMENT

卷:270

Article

Yamasaki, Takuhei¹  Nishikiori, Tatsuhiro^1,2  Suzuki, Satoshi¹ 

[1] Fukushima Prefectural Ctr Environm Creat, 10-2 Fukasaku, Fukushima 9637700, Japan

[2] Natl Agr & Food Res Org, Tohoku Agr Res Ctr, Agr Radiat Res Ctr, 50 Harajukuminami, Fukushima, Fukushima 9602156, Japan

关键词: Radiocesium;    River;    Sediment;    Flood channel;    Decontamination;    Recontamination;   

DOI  :  10.1016/j.jenvman.2020.110856

来源: Elsevier

【 摘 要 】

The accident at the Fukushima Dai-ichi Nuclear Power Plant in March 2011 resulted in the widespread deposition of radiocesium in and around Fukushima prefecture. Riversides have an additional contamination risk through deposition of material containing radiocesium transported from upstream. In our previous research (Nishikiori and Suzuki, 2017) we developed a decontamination method in a river bank in 2014; however, the decontaminated site had a recontamination risk. In this study, we evaluated the effectiveness of plant removal as a countermeasure against recontamination because plants favor the deposition of highly-contaminated fine particles. Although suspended solids with high radiocesium concentrations were transported, under plantremoval conditions (2015-2016), sediment deposited in the flood channel was sandy with low radiocesium concentrations. In 2017, one year after the plant recovery, somewhat muddy sediment with high radiocesium concentrations was deposited during medium rainfall events; the plant biomass would explain the amount of fine sediment that was deposited. Additionally, large typhoons introduced sandy sediment even on the densely vegetated flood channel. Thereby, the air dose rates did not increase during the observation period. Plant removal may control the deposition of highly contaminated sediments and be an effective countermeasure for recontamination in the flood channel.

【 授权许可】

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