The Thirty Years’ Results of Radiation Hygienic Monitoring of Tula Region territories contaminated due to the Chernobyl NPP accident

• Main Authors: V. V. Boldyreva, V. V. Ovcharova
• Format: Article
• Language: English
• Published: Saint-Petersburg Research Institute of Radiation Hygiene after Professor P.V. Ramzaev 2016-07-01
• Series: Radiacionnaâ Gigiena
• Subjects: the chernobyl npp accident; radiation contamination; radiation monitoring; radionuclides; maximum permissible levels; radiochemical and spectrometric studies; population doses
• Online Access: https://www.radhyg.ru/jour/article/view/370

Over 50% of Tula Region areas were contaminated after the Chernobyl NPP accident. The article provides the thirty years’ results of radiation hygienic monitoring of the Chernobyl accidental fallout - affected areas in Tula Region. The radiation situation is assessed at the initial accidental period and at the current stage. The initial levels of gamma - radiation dose intensity (up to 35 mcSv/hr ) are identified for the period of the “iodine” hazard along with the tabular data on the dose intensity relative stabilization by the beginning of August 1986 due to iodine-131 decay. The information is presented regarding iodine-131 tentative maximum permissible level exceedance in the dairy products of the two most contaminated regional areas - Plavskoye and Arsenievskoye. The article also provides the laboratory data on the total beta - activity in the foodstuffs in 1986-1987 and cesium-137 maximum permissible level exceedence in 1986. The radionuclide maximum permissible level exceedances in foodstuffs were registered only in 1986 due to the plants surface contamination whereas in the forest mushrooms those exceedances were repeatedly found until 2004. The black earths and grey forest soils had a benign impact upon the intensity of the radionuclide transfer into plants which resulted in the formation of internal radiation doses.At the current stage, the content of cesium-137 and strontium- 90 in the foodstuffs can only be quantified by a radiochemical method. The table covers all the districts within the boundaries of radiation contaminated zones. The radiochemical studies indicate the main dose - forming products. The article contains the table of internal and external radiation doses of the population in Plavsk town over 1986-1990 and displays the factors impacting population’s internal and external exposure. The Chernobyl - affected exposure dose of the population is mostly attributed to the external radiation and, for over twenty years, it does not exceed 1 mSv/ year. The annual effective dose of the population from 96,2% of the settlements is below 0,3 mSv/year.