Simulation of ¹³⁷Cs transport and deposition after the Chernobyl Nuclear Power Plant accident and radiological doses over the Anatolian Peninsula

The Chernobyl Nuclear Power Plant (CNPP) accident occurred on April 26 of 1986, it is still an episode of interest, due to the large amount of radionuclides dispersed in the atmosphere. Caesium-137 (¹³⁷Cs) is one of the main radionuclides emitted during the Chernobyl accident, with a half-life of 30years, which can be accumulated in humans and animals, and for this reason the impacts on population are still monitored today. One of the main parameters in order to estimate the exposure of population to ¹³⁷Cs is the concentration in the air, during the days after the accident, and the deposition at surface. The transport and deposition of ¹³⁷Cs over Europe occurred after the CNPP accident has been simulated using the WRF-HYSPLIT modeling system. Four different vertical and temporal emission rate profiles have been simulated, as well as two different dry deposition velocities. The model simulations could reproduce fairly well the observations of ¹³⁷Cs concentrations and deposition, which were used to generate the 'Atlas of Caesium deposition on Europe after the Chernobyl accident' and published in 1998. An additional focus was given on ¹³⁷Cs deposition and air concentrations over Turkey, which was one of the main affected countries, but not included in the results of the Atlas. We estimated a total deposition of 2-3.5PBq over Turkey, with 2 main regions affected, East Turkey and Central Black Sea coast until Central Anatolia, with values between 10kBqm^-2 and 100kBqm^-2. Mean radiological effective doses from simulated air concentrations and deposition has been estimated for Turkey reaching 0.15mSv/year in the North Eastern part of Turkey, even if the contribution from ingestion of contaminated food and water is not considered, the estimated levels are largely below the 1mSv limit indicated by the International Commission on Radiological Protection.