A prognostic estimation of the area contaminated with alpha-emitting transuranium isotopes in Belarus following the Chernobyl accident

As a result of the Chernobyl accident, some regions of Belarus have been contaminated with the plutonium isotopes 238,239,240,241Pu. Considering the importance of the environmental impact of the alpha-emitting radionuclides we have carried out a prognostic estimation of the area contaminated with 238,239,240Pu and 241Am (the latter being a decay product of 241Pu) in Belarus. The calculations were made using measurements of 238,239,240Pu activity concentrations in soil samples from about 600 settlements in the affected region, together with the estimated activity ratio A(241Am)/A(238,239,240Pu). The area contaminated with alpha-emitting transuranium isotopes predicted for the year 2006 has been compared with that estimated for 1986. The results show that by 2006, the area of inhabited districts where contamination with 238,239,240Pu and 241Am exceeds the threshold level of 740 Bq/m2, will be 3.7 times larger, reaching approximately 3.5 × 103 km2. Of this, almost 20% will have a contamination level of 1850-3700 Bq/m2.