Report regarding radioactivity removal from contaminated vegetables derived from the Fukushima nuclear accident

抄録

  Huge amounts of radioactivity derived from the Fukushima nuclear accident were scattered in the atmosphere. Various kinds of vegetables in three prefectures in the Tohoku area were contaminated with ¹³¹I and ¹³⁷Cs over the legal limit for shipment. A simple and effective removal method for contaminated farm products was developed to ensure the relief of farmers and the security of consumers. Distribution imaging of radioactivity in the contaminated vegetables, the physical removal of radioactivity from contaminated vegetables and the chemical removal of radioactivity from contaminated vegetables were examined. As a result, there were two types of vegetable contamination, spot type or spread type. The concentration of radioactivity was higher on the outer side than the inner side of a vegetable leaf. More than 80% of radioactivity attaches to the surface of leaves. Radioactivity removal by water washing showed no significant difference between boiling water and cold water. There was no significant difference between hand-washing and running water washing. The radioactivity of vegetables decreased by 70-80% for ¹³¹I and more than 80% for ¹³⁷Cs by reducing agent treatments. In particular, ascorbic acid is promising as a safe and versatile option.