Four‐year decline in radioactive cesium transfer to perennial Gramineae candidate bioenergy crops in a field polluted by radioactive fallout from the Fukushima Daiichi Nuclear Power Plant in 2011

Abstract

The accident caused at the Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Plant by the Great East Japan Earthquake of 11 March 2011 resulted in radioactive fallout over a wide area of eastern Japan. Production of bioenergy crops and their conversion to energy may be one way to resume agricultural production at an early date and to put renewable energy to practical use. We examined yearly changes in radioactive cesium concentrations in the harvested parts of six perennial Gramineae candidate bioenergy crops and the distribution of the cesium in plant organs and rhizosphere soil layers under no-till conditions in an experimental field 112 km from the nuclear power plant. Average radioactivity of the sum of cesium-134 and cesium-137 in the harvested parts (foliage) of the six bioenergy crops on the day of harvest declined considerably from 193.3 Bq kg À1 in 2011 to 31.6% of the 2011 level in 2012, 28.8% in 2013and 28.7% in 2014. Radioactivity was higher in the underground plant parts (subterranean stem and root) than in the aboveground parts (foliage and stubble). In 2014, radioactivity in the untilled rhizosphere soil was higher in the shallow layer (0-5 cm from the soil surface) than in the deeper layers, indicating that rainfall and perennial bioenergy crop cultivation for more than 3 years had a limited effect on the soil distribution of the fallout. These results provide unique and specific information on radioactive cesium transfer to bioenergy crops and could help in the planning of feedstock supplies in radiation-polluted areas.

Radioactive Cesium Concentration in Silage Corn (<i>Zea Mays</i> L.) and Italian Ryegrass (<i>Lolium Multiflorum</i> Lam.) Cultivated with Three Different Tillage Methods after the Fukushima Daiichi Nuclear Power Plant Accident

“…To prevent radioactive cesium (Cs) contamination of forage crops, various countermeasures were examined and then immediately implemented (Tsuiki & Maeda 2012a, 2012b, Kobayashi et al 2013, Harada et al 2014, Ogura et al 2014, Yamamoto et al 2014, Shinano 2015, Sunaga et al 2015, Kobayashi et al 2016, Komissarov et al 2017. Those studies and subsequent implementation of countermeasures utilized information and knowledge mainly obtained after the Chernobyl accident in 1986 (Alexakhin 1993, Konoplev et al 1993, Lembrechts 1993, Lönsjö et al1989, Nisbet et al 1993, Segal 1993, Roed et al 1996, Fesenko et al 2007.…”