Aerosol activity measurements associated with the burning of peat materials (evacuation zone of the Bryansk Region)

In April and August 2015, a massive fire occurred in the Chernobyl Exclusion zone. The fire spread to neighboring areas due to the prevailing strong winds. In this paper, we analyze the peat fires as a unique source of radioactive contamination. After an expedition directly to the peat fire site (the evacuation zone of the Bryansk region), we collected a number of aerosol samples. We came to the conclusion that peat fires cannot be the reason for radioactive particle transport in the Bryansk region as well as in the Chernobyl evacuation zone. During the peat fire, radioactive contamination was not transferred by aerosols beyond 500 m. The 137 Cs concentration in the aerosol filters varied between 0.55 and 0.64 Bq/m 3 , and that at the same distance from the fire seat and peat edge was 4.4∙10 −3 Bq/m 3 ; the activity values in the peat bog and in the nearest inhabited locality did not exceed the background values. Strontium-90 was not found in aerosol samples. The soil-to-air transport rate of 137 Cs was 2.7∙10 −6 . After the Chernobyl accident, the majority of the 137 Cs was incorporated into the structure of clay minerals, and these did not change during the peat fire. The mobility of 137 Cs in the flight peat material particles was established. To confirm the territory status of the evacuation zone, we also collected some food samples. Berries and mushrooms consumed at the assumed rate for dose estimation would result in doses that exceed the public dose limit by approximately a factor of five. • In the case of peat fires, aerosols beyond 500 m did not transport radioactive contamination. • The main amount of 137 Cs was incorporated into the structure of clay minerals and it doesn't changed during the peat fire. • The main contribution to internal radiation dose for a human make berries and mushrooms from the surrounding territory.