Reconstruction of radio-ecological model parameters based on the results of monitoring the radiation situation in Mazovia after the Chernobyl accident (based on the «Warsaw» scenario of the IAEA EMRAS project)

The paper analyzes the consistency of the input data of the radioecological model: the results of measurements of 137Cs and 131I concentrations in the atmosphere after the Chernobyl accident in Warsaw, the meteo-data on precipitation during the main radioactive fallout, the values of minimum 137Cs deposition densities on the territories of two dairy areas of Warsaw Area and Ostroleka Area in the central part of Mazovia. According to meteorological data in Warsaw Area during the period of radioactive fallout there were local rains. In Ostroleka Area, according to all weather stations, there was no rainfall during this period. In Warsaw Area, a minimum 137Cs deposition density of 1.3 kBq/m² with an error of less than 10% was found to be consistent with the “dry” deposition density of 137Cs (1.2 kBq/m²) reconstructed by a simulated agroclimatic model based on atmospheric 137Cs measurements. This agreement, taking into account the amount of precipitation recorded at weather stations during the period of radioactive fallout and the significant, more than 10 times, dispersion of 137Cs fallout densities across the Warsaw Area, suggests that a homogeneous cloud-uniform fallout model is preferable for this region in radio-ecological modeling. For the Ostroleka Area, the variation in deposition densities of 137Cs was relatively small, at 3.2, and the estimated dry deposition density of 137Cs was 2.0-2.7 times lower than the measured minimum deposition densities in districts and settlements. This discrepancy, given the absence of precipitation recorded by all weather stations during the deposition period, led to the assumption that the 137Cs and 131I atmospheric concentrations in Ostroleka Area were 2-2.7 times higher than those in Warsaw Area. The adjustment of the 137Cs and 131I atmospheric concentrations in the Ostroleka Area for this region will be verified by measuring the 131I specific activity in milk under the Warsaw scenario.

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