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Complete inspection of rice produced in Fukushima prefecture Rice radiocesium contamination levels after Fukushima Dai-ichi nuclear accident

April 7, 2015

© 2015 Naoto Nihei, Keitaro Tanoi and Tomoko M. Nakanishi

© 2015 Naoto Nihei, Keitaro Tanoi and Tomoko M. Nakanishi

Agricultural products in Fukushima Prefecture have been inspected to verify safety ever since the accident at the Fukushima Daiichi Nuclear Power Plant of Tokyo Electric Power Company. Fukushima Prefecture and the Japanese government have issued more detailed directives for the inspection of rice within the prefecture compared to other agricultural products because rice is the main staple food of the Japanese diet.

Dr. Naoto Nihei and his colleagues described the inspection of radiocesium concentration levels in rice produced in Fukushima Prefecture, Japan, in the 3 years since the nuclear accident in 2011. In 2011, three types of verification (preliminary survey, main inspection, and emergency survey) revealed that rice with radiocesium concentration levels over 500 Bq/kg (the provisional regulation level until March 2012 in Japan) were identified in areas to the north and west of the Fukushima Daiichi nuclear power plant. 0.8% of the rice samples in the entire Fukushima Prefecture had radiocesium concentration levels higher than 100 Bq/kg (the new standard since April 1 in 2012) in 2011. The internal exposure of the average adult eating rice grown in the area to the north of the nuclear plant was estimated at 0.05 mSv/year. In 2012, Fukushima Prefecture authorities decided to inspect the radiocesium concentration levels in all rice using custom-made belt conveyor testers. Notably, rice with radiocesium concentration levels over 100 Bq/kg were detected in only 71 bags out of the total 10,338,000 in 2012 and 28 bags out of the total 11,001,000 in 2013.

The present information suggests that there was almost no rice exceeding 100Bq/kg produced in Fukushima Prefecture three years after the nuclear accident, and the safety of Fukushima’s rice is ensured through of the inspection of all rice.

Paper

Naoto Nihei, Keitaro Tanoi and Tomoko M. Nakanishi, "Inspections of radiocesium concentration levels in rice from Fukushima Prefecture after the Fukushima Dai-ichi Nuclear Power Plant accident", Scientific Reports 5, Article number 8653: 2015/03/04 (Japan time), doi: 10.1038/srep08653.
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Graduate School of Agricultural and Life Sciences

Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences

Laboratory of Radio Environmental Technology, Department of Biological and Environmental Engineering

Laboratory of Radio-plant Physiology, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences

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