COMPREHENSIVE RADIOLOGICAL AND HYGIENIC MONITORING OF PARTICULAR SETTLEMENTS OF KYIV REGION IN 2019

Abstract

Objective.to identificate the main factors and assess their impact on the formation of radiation doses to the population of radioactively contaminated areas of Kyiv region at the current stage of the accident based on complex radiation and hygienic monitoring in the reference settlements in 2019. Materials and methods. Comprehensive radiological and hygienic monitoring was carried out in eight settlements of Kyiv region – villages of Ragivka, Lygovyky, Mar’yanivka, Zelena Poliana of Polis’kyi district and villages of Hornostaipil, Dytiatky , Pisky, Karpylivka of Ivankiv district. The content of incorporated 137Сs was determined with direct measurement on whole body counters (WBC) samples of basic foodstuffs were collected to determine the content of radionuclides 90Sr and 137Сs, residents were interviewed about the levels of consumption of these products, and work was performed to estimate external radiation doses. Mathematical, dosimetric, radiochemical methods are used in the work. Results. There was a further decrease in annual doses of internal radiation in the surveyed settlements in 1.3 times, both in Polis’kyi district (0.041 mSv · year-1 in 2016, 0.030 mSv · year-1 in 2019) and in Ivankiv district (0.023 mSv · year-1 in 2016, 0.018 mSv · year-1 in 2019). It is possible to state a slowdown in the reduction of radiation doses compared to previous years: from 2010 to 2013, the annual doses of internal radiation in the surveyed settlements decreased by 1.8–2.4 times, from 2013 to 2016 – by 2.3–3.6 times. The content of 137Сs and 90Sr in milk and potatoes in the inspected settlements is lower than the permissible level of the Hygienic Standard HS 6.6.1.1-130-2006 and the use of these foods can not significantly affect the formation of the internal radiation dose. The content of 90Sr in milk samples in the settlements of Ivankiv district is in the range of 2.1–9.9 Bq · kg-1 (in 2016: 1.3–7.4 Bq · kg-1), which does not exceed the permissible level of 20 Bq · kg-1, but due to the dynamics needs further monitoring. The content of 137Сs in samples of dried mushrooms collected from residents of Kyiv region in 2019, as in previous years, is significantly (up to 100 times) higher than permissible level, and has a high uncertainty – from 1.4 kBq · kg-1 to 223.7 kBq · kg-1. Conclusions. It is established that the annual effective radiation doses of the population in the surveyed settlements in the current year are formed due to internal radiation doses that do not exceed 0.46 mSv · year-1 in Ivankiv district and 0.51 mSv · year-1 in Polis’kyi district, which below the RCT criterion 1 mSv · year-1. The main factor that forms the dose of internal radiation of the residents of the surveyed state of emergency of Kyiv region is the intake of 137Сs in the body with forest products, primarily mushrooms. Key words: internal dose, external irradiation; WBC-monitoring, 137Сs, 90Sr.