COMPLEX RADIATION AND HYGIENIC MONITORING OF POPULATION ON RADIOLOGICALLY CONTAMINATED TERRITORIES OF ZHYTOMYR OBLAST IN 2021. / KOMPLEKSNYI RADIATsIINO-GIGIIeNIChNYI MONITORYNG MEShKANTsIV RADIOAKTYVNO ZABRUDNENYKh TERYTORII ZhYTOMYRS'KOÏ OBLASTI U 2021 ROTsI.

OBJECTIVE: the key factors identification in radiation dose formation in population of radiologically contaminatedareas of Zhytomyr oblast in the current period of accident through complex radiation and hygienic monitoring in reference settlements in 2021. MATERIALS AND METHODS: For complex radiationhygienic monitoring in Zhytomyr oblast, 10 settlements were chosen - Narodychi, Selets, Bazar, Rudnya Bazarska, Khrystynivka - zone 2, Motiyki, Zalissya, Davydky, Radcha, Nova Radcha - zone 3 of Narodychi district, in which the highest radiation doses were recorded after the accident at the Chornobyl Nuclear Power Plant. The research was carried out in June 2021. In order to determine the doses of internal radiation, 645 measurements were performed on whole body counters (WBC) (478 adults and 167 children). The 44 samples of milk, 45 samples of potatoes and vegetables, and 38 samples of wild products were collected in local farms and measured for the 137Cs and 90Sr content. Residents of the studied settlements (n = 220, 175 adults, and 45 children) were interviewed about the levels of consumption of staple foodstuffs. External radiation doses were evaluated in all the studied settlements. Mathematical, dosimetry, and radiochemical methods were applied. RESULTS AND CONCLUSIONS: Annual effective radiation doses of Zhytomyr oblast population in 2021 were formedmainly due to internal radiation ones that not exceeded 1.8 mSv * year-1 in adults and 0.5 mSv * year-1 in children against the radiologically contaminated territories (RCT) criterion of 1 mSv * year-1. Intake of 137Cs with milk and wild mushrooms, which traditionally occupy a significant part of diet in Zhytomyr oblast area and have consistently high levels of radioactive cesium contamination, remains a key factor of internal radiation dose forming in residents of the surveyed settlements of Zhytomyr oblast.

RETINA VESSELS CHANGES IN CHORNOBYL NUCLEAR POWER PLANT EMPLOYEES WHO EXPERIENCED LONG-TERM ABNORMAL RADIATION EXPOSURE AT THE WORKPLACE AS A RESULT OF THE OCCUPATION OF CHORNOBYL NUCLEAR POWER PLANT IN 2022. / ZMINY SUDYN SITKIVKY V SPIVROBITNYKIV ChORNOBYL'S'KOÏ ATOMNOÏ ELEKTROSTANTsIÏ, IaKI ZAZNALY TRYVALOGO NENORMOVANOGO RADIATsIINOGO VPLYVU NA ROBOChOMU MISTsI VNASLIDOK OKUPATsIÏ ChAES U 2022 ROTsI.

During the occupation of the Chornobyl Nuclear Power Plant (ChNPP) in 2022, a group of employees remained in the working town for a long time. These personnel were exposed to long-term radiation and non-radiation factors of the production environment, as well as stress and other factors. These factors could result in negative changes of health.It is known that radiation exposure causes changes in the course and caliber of retinal vessels. OBJECTIVE: to assess the condition of retinal arteries and veins and the level of incorporated 137Cs content in persons who were exposed to prolonged exposure to radiation and non-radiation factors of industrial environment, as they were at the workplace overtime during the occupation of the Chornobyl Nuclear Power Plant in 2022. MATERIALS AND METHODS: A comprehensive ophthalmological examination was carried out. Which included the determination of the diameter of the retinal arteries and veins, the arteriovenous ratio, of 55 people from among the personnel of the ChNPP, who worked under the conditions of the occupation of the ChNPP. All those examined were examined on an expert human radiation counter. The results of the ophthalmological examination were compared with the results of earlier examinations of ChNPP employees of the same age groups. RESULTS: It was established that in the examined group, a decrease in the arterio-venous ratio was observed, mainly due to the expansion of retinal veins. Dilatation of the veins was asymmetric, mainly the branches of the central vein of the retina of the right eye were more dilated. Retinal arteries were narrowed in all examined subjects. When comparing the results with the data of previous examinations, it was established that the arterio-venous ratio in this group was probably lower than in previously examined employees of the ChNPP of the same age groups. At the same time, the maximum registered value of the content of incorporated 137Сs was 713 Bq/organism, none of the examined exceeded the control level of 1,000 Bq/organism. CONCLUSIONS: Violation of blood circulation in the retina was detected - a probable increase in the arteriovenous ratio due to the expansion of the retinal veins in the personnel of the Chornobyl nuclear power plant who worked under the conditions of the occupation of the ChNPP in 2022. Since the examined subjects did not exceed the control level of incorporated 137Сs content (1,000 Bq/organism), the observed effect may be a consequence of the influence of other, both radiation and non-radiation factors.

COMPREHENSIVE RADIATION AND HYGIENIC MONITORING IN POPULATION OF THE RIVNE OBLAST RADIOLOGICALLY CONTAMINATED TERRITORIES. / KOMPLEKSNYI RADIATsIINO/GIGIIeNIChNYI MONITORYNG MEShKANTsIV RADIOAKTYVNO ZABRUDNENYKh TERYTORII RIVNENS'KOÏ OBLASTI U 2020 r.

OBJECTIVE: The key factors identification in radiation dose formation in population of radiologically contaminatedareas of Rivne oblast in the current period of accident through comprehensive radiation and hygienic monitoring inreference settlements in 2020 and estimation of their impact on dose formation were the study objectives. MATERIALS AND METHODS: Comprehensive radiation and hygienic monitoring of settlements in Rivne oblast(province) was provided in Stare Selo, Vezhytsia, Perekhodychi, and Drozdyn villages of Rokytne district, where thehighest radiation doses were registered after the ChNPP accident. Studies were conducted in September 2020.Measurements (n=696, 318 adults, and 378 children) were performed using the whole body counters (WBC) to deter-mine the internal radiation doses. The 48 samples of milk, 45 samples of potatoes and vegetables, and 35 samplesof wild products were collected in local farms and measured for the 137Cs and 90Sr content. Residents of the studiedsettlements (n=229, 140 adults, and 89 children) were interviewed about the levels of consumption of staple food-stuffs. External radiation doses were evaluated in all the studied settlements. Mathematical, dosimetric, and radio-chemical methods were applied. RESULTS AND CONCLUSIONS: Annual effective radiation doses of the Rivne oblast population in 2020 were formedmainly due to internal radiation ones that not exceeded 1.24 mSv · year-1 in adults and 0.65 mSv · year-1 in childrenagainst the RCT criterion of 1 mSv · year-1. Further 1.2-1.9-fold decrease in the annual internal radiation doses vs.the results of WBC-monitoring in autumn of 2017 was registered in the surveyed settlements. The latter confirmeda time pattern of radiation levels gradual reduction at the current stage of Chornobyl accident since 2011. Intakeof 137Cs with milk and wild mushrooms, which traditionally occupy a significant part of diet in the Rivne Polissya areaand have consistently high levels of radioactive cesium contamination, remains a key factor of internal radiationdose forming in residents of the surveyed settlements of Rivne oblast.

RECONSTRUCTION, VERIFICATION AND ANALYSIS OF RESULTS OF WBC MEASUREMENTS DATED 1986 THAT WERE INPUTTED TO ELECTRONIC DATABASE IN 2019-2021. / VIDNOVLENNIa, VERYFIKATsIIa TA ANALIZ REZUL'TATIV LVL/VYMIRIuVAN' 1986 R., ShchO VNESENI DO ELEKTRONNOÏ BAZY U 2019­2021 rr.

Objective of research is to improve the electronic database of WBC measurements dated 1986 by inputting of newinformation from paper carriers, reconstruction of information gaps, verification and analysis of new entered data,revision of internal exposure doses that are based on results of WBC measurements dated 1986. MATERIALS AND METHODS: In 2013-2015 during a revision of databases (DB) of WBC measurements results dated1986-2014, it was discovered a great amount of paper carriers with information about WBC measurements, includ-ing the ones dated 1986, that were not inputted to the electronic DB. The paper carriers were systematized andordered by the following indicators: place of residence of a person and place of WBC measurement, institution andoperator that made the measurement, measurement device and date of measurement. For a comfortable inputtingof the information to the electronic DB, it was additionally created a form which exists as an option in existing program complex Silbody (Version 19.0.9). In the revised DB of WBC measurements dated 1986 internal exposure dosesfrom radio-cesium of Chornobyl origin were computed based on an ecological and dosimetric model for radio-cesiummigration in environment and a model for radio-cesium metabolism in human body. In the work, mathematical andstatistical methods of research were used. RESULTS: In 2019-2021 additionally 35,319 notes were inputted to the electronic DB of WBC measurement dated1986, and as a result its volume increased in 2.2 times. Mostly those are data on results concerning residents of Kyiv,Zhytomyr, Donetsk, Cherkasy, Odessa, Ivano-Frankivsk, and Rivne Oblasts. It was established the information onmeasurement devices and respectively on the minimal detected activity (MDA) for 27,119 notes (76.7 % of all newentered). Information is reconstructed about the body mass of all persons under investigation. Evaluation is madefor values of intake of incorporated radionuclides 137Cs and 134Cs for all new entered to DB. Quality of reconstructedinformation was analyzed. To group 1, «qualitative¼, it was classified 18,598 notes (53 % of all new entered), measurements in 1986 (including new entered). Dose not exceeding 1 mSv was obtained by 80 % of adults (older than20), as well as 73 % of persons younger than 20. CONCLUSION: To DB of WBC measurements, it was additionally inputted 35,319 notes on results of measurementsdated 1986. New entered information is verified and distributed by the quality groups. Individual exposure dosesevaluated based on those data can be used for further scientific research.

RESULTS OF WBC-MONITORING OF FIREFIGHTERS PARTICIPATING IN RESPONSE TO CHORNOBYL FOREST FIRES IN APRIL-MAY 2020. / REZUL'TATY LVL-MONITORYNGU POZhEZhNYKh, ShchO BULY ZADIIaNI U GASINNI LISOVOÏ POZhEZhI V ZONI VIDChUZhENNIa ChAES U KVITNI­TRAVNI 2020 ROKU.

OBJECTIVE: of this study was to determine the levels of radionuclides in the rescuers' bodies of the SES during firefighting in the exclusion zone of the Chornobyl nuclear power plant and to assess the dose of internal radiation dueto this receipt. MATERIALS AND METHODS: From 06.04.2020 to 19.05.2020 in the State Institution «National Research Center forRadiation Medicine of the National Academy of Medical Sciences of Ukraine¼ (NRCRM) measurements of the contentof incorporated gamma radionuclides on whole body counters (WBC) operational class «Screener-3M¼ (Minimumdetected activity (MDA) is 300-500 Bq for 5 minutes of measurement at 137Cs) and expert high-sensitivity WBC (MDAis 20 Bq for 10 minutes of measurement at 137Cs). 470 people (523 measurements) in three groups of personnel ofthe SES of Ukraine who took part in the forest fire liquidation in the exclusion zone in the period from April 4 toMay 5, 2020 were examined. Mathematical and spectrometric methods are used in the work. RESULTS AND CONCLUSIONS: In the vast majority (95 %) of the personnel of the SES of Ukraine, examined at the WBCoperational class «Screener-3M¼ (more than 500 measurements), the assessment of the values of the individualeffective dose of internal radiation due to 137Cs in the body during firefighting, assuming that it receipt occurredduring operation in the exclusion zone, did not exceed the minimum dose detected by MDD (5-14 µSv). The average value of the effective dose of internal radiation in the group of personnel of the State Emergency Service ofUkraine in Kyiv, which participated in the elimination of forest fires in the exclusion zone from April 4 to May 5, 2020(26 people) studied at the expert WBC, is 2.5 ± 1.1 µSv, in the group of personnel of the SES of Ukraine in Cherkasyregion, which participated in the fire on April 19-24, 2020 (9 people) - 2.2 ± 0.6 µSv, in the group of personnel ofthe SES of Ukraine in the Kyiv region, which took part in the elimination of the forest fire in the exclusion zone onApril 4 - May 5, 2020 (42 people) - 4.4 ± 2.4 µSv. Maximum values of 5.1 µSv, 3.5 µSv, 11.8 µSv in the groups ofKyiv city, Cherkasy and Kyiv regions, respectively, which is much lower than the basic dose limit for the populationfrom man-made sources of 1000 µSv · year-1 according to the Law of Ukraine about protection of the person againstinfluence of ionizing radiation.

RESULTS OF WBC MEASUREMENTS WERE MADE AT RADIOACTIVELY CONTAMINATED TERRITORIES OF UKRAINE IN 1986-2014 (REVISION AND ANALYSIS). / REZUL'TATY LVL6VYMIRIuVAN', PROVEDENYKh NA RADIOAKTYVNO ZABRUDNENYKh TERYTORIIaKh UKRAÏNY U 1986-2014 rr. (REVIZIIa TA ANALIZ).

OBJECTIVE: revision, analysis, and significant improvement of quality of the database of WBC measurements made in1986-2014 at radioactively contaminated territories of Ukraine by the use of renewal of informational gaps andimprovement of the model for assessment of internal exposure doses. MATERIALS AND METHODS: Inthe periodfrom 1986 to 2014 experts of the Whole Body Counters Laboratory of NRCRMaccumulated about 1.5 million results of WBC measurementsof radio-cesium incorporated in the body of personsresiding at the territories which are radioactively contaminated due to Chornobyl accident. Most of measurements(~64 %) were made during the first 15 years after the accident. The most of measurements were made in Kyiv (~23 %),Zhytomyr (~36 %), Rivne (~20 %) and Chernihiv (~5 %) Oblasts. Works on revision of database of WBC measurementsincluded: transformation of data saved in paper format into electronic form, checking for correctness and correspon-dence of information, renewal of lacking information at the fields of database, improvement of the model for eval-uation of internal exposure doses by the data of WBC measurements. In the model for evaluation of revised doses,it is assumed uniform content of radio-cesium during a year. Reference values are used of metabolism parametersand anthropometric human parameters recommended in publications of ICRP. RESULTS: Revised doses have been reconstructed for 1,386,585 records of data base of WBC measurements that fitspecially elaborated criterions for estimation of quality of results. Among them 604,215 records are WBC measure-ments of children and adolescents younger than 18, and 782,370 records correspond to adult inhabitants of Ukraine,most of which reside in Zhytomyr, Kyiv, Rivne and Chenihiv Oblasts. CONCLUSIONS: Obtained results serve as a ground for further works on improvement of models for evaluation of pass-port doses and individualized exposure doses of subjects registered in Ukrainian State Register - of persons thataffected due to Chornobyl accident. Evaluated doses can be used for epidemiological, clinical and other research.