Triple digging — a simple method for restoration of radioactively contaminated urban soil areas

External radiation doses to urban or suburban populations after the Chernobyl accident in 1986 are often dominated by contributions from soil areas near dwellings. Previously reported procedures for reclamation of contaminated soil are generally inadequate or expensive to carry out in this type of area. Therefore, a new technique has been examined in a heavily contaminated area of Russia. The triple digging method requires only the use of a shovel and can be carried out by the local populace. The field test in 1995 showed that although the contamination had migrated rather deep into the soil, triple digging can still reduce the external dose rate by as much as a factor of 10, if a large part of the open area is treated. The method has little impact on the soil fertility and has the beneficial side-effect that it reduces the uptake of contamination to plants grown in the area.