Decontamination of radioactivity from contaminated vegetables derived from the Fukushima nuclear accident

Many kinds of vegetables were contaminated by a huge amount of radioactivity, such as 131I or 137Cs, derived from the Fukushima nuclear accident. The concentration of radioactivity in contaminated vegetables was higher than the value of the legal limit for shipment, therefore, we attempted to identify a simple and effective removal method for contaminated farm products to ensure the relief of farmers and the security of consumers. First, the radioactivity distribution and adhesion state of contaminated vegetables were investigated by an imaging plate (IP) image. As a result, there were two types of contamination, spot type or spread type, of vegetables. The removal of radioactivity by physical or chemical methods was investigated. As a result, 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 result of chemical removal showed that reducing agents removed radioactivity from vegetables by 70–80% for 131I and more than 80% for 137Cs. In particular, ascorbic acid is promising as a safe and versatile option.

► Two types of contaminations (Spot and Spread) were observed in contaminated vegetables. ► Removal ratio wasn't difference between hand-wash and running water wash. ► The removal of 131I is difficult with both cold water wash and hot water wash. ► 1% ascorbic acid removed radioactivity in vegetable by >75% at 131I and 137Cs.