Gov’t eyes 5,000-8,000 Bq/kg as radiation limit for polluted soil to be reused

8 June 2016

The Environment Ministry has mapped out a basic policy on the reuse of contaminated soil in Fukushima Prefecture for public works such as road construction. The policy specifies how to use recycled soil polluted by radioactive fallout from the 2011 nuclear accident at Tokyo Electric Power Co.’s Fukushima Daiichi plant as well as maximum levels of radiation in soil allowed for reuse.

The policy was unveiled at an expert study meeting held by the ministry in Tokyo on June 7. Earlier, the ministry had indicated it will limit maximum radioactive content in polluted soil to be recycled to 8,000 becquerels per kilogram. The new policy calls for usable maximum contamination levels ranging from 5,000 to 8,000 Bq/kg depending on soil applications and work periods. The levels are designed to keep the dosage of workers’ exposure to radiation at 1 millisievert or less per year.

In case work is continued for a year to use polluted soil for road embankment and cover it with earth, sand and asphalt, the tolerable level of soil contamination is “6,000 Bq/kg or less.” If road embankments are covered with more than 50 centimeters of unpolluted earth, sand and other materials, additional radiation exposure to residents in the neighborhood can be restricted to 0.01 millisievert or less a year, according to the ministry.

Recycling of contaminated soil is to be limited to embankments and other applications in public works such as road and levee construction in and outside the prefecture. The ministry says it will take safety measures to prevent polluted soil from being scattered and flowing out. But it faces the challenging task of how to obtain understanding of residents in relevant municipalities before polluted soil can be put to reuse.

(Translated by Kyodo News)