Wildfires in the Chornobyl exclusion zone – Risks and consequences

Following the 1986 Chornobyl accident an area of approaching 5000 km² surrounding the nuclear plant was abandoned, creating the Chornobyl Exclusion Zone (CEZ). Whilst this area likely contains the most radioactive terrestrial ecosystem on earth, over the nearly 35 years since the accident the absence of humans and associated activities has resulted in increases in wildlife numbers. Both the Belarussian and Ukrainian components of the CEZ are now designated as nature reserves; together they form one of Europe's largest protected areas and have been described as an iconic example of rewilding. Forests and former agricultural land (now scrub) dominate the CEZ and wildfires are an annual event. In April 2020, the CEZ suffered its most widespread fires to date when >800 km² of the 2600 km2 Ukrainian portion of the CEZ was burnt. Largescale fires in the CEZ have implications for wildlife, as they do elsewhere, but they also pose additional radioecological and radiological protection questions. We discuss the implications of wildfires in the CEZ, considering effects on wildlife and changes in radionuclide mobility. We also demonstrate that the risk to firefighters and the wider public from the inhalation of radionuclides in smoke resulting from fires in the CEZ is likely to be low. However, further experimental and modelling work to evaluate potential doses to firefighters from inhaled radioactive particles would be valuable, not least for reassurance purposes.