Radionuclide Specific Activities Research Articles

Dynamics of 137Cs content in higher aquatic plants of Kyiv and Kaniv Reservoirs

The study aimed to determine the temporal parameters of 137Cs specific activity in higher aquatic plants of Kyiv and Kaniv reservoirs. Parameters characterizing the dynamics of 137Cs content for hydrophytes (Potamogeton perfoliatus and Ceratophyllum demersum) and helophytes (Phragmites australis and Typha angustifolia) were determined based on the results of 137Cs specific activity determination in the aboveground plant organs. Plant samples were collected in 1989–2021 from a polygonal area in the upper part of Kyiv reservoir (shallow waters near Strakholyssia village) and in 2000–2021 from a polygonal area in the middle part of the Kaniv reservoir (shallow waters near Rzhyschiv and the Borispol islands). A model of specific activity of aquatic organisms was substantiated (or developed) in case of exponential decrease in radionuclide levels in the environment. The main parameter of the model is the period of resulting halving of organism specific activity due to the decrease in radionuclide concentration in water, its irreversible fixation in bottom sediments, and radioactive decay. During 1989–2021, the half-life period of 137Cs specific activity in Potamogeton perfoliatus, Ceratophyllum demersum, and Phragmites australis of Kyiv reservoir was 5.4 years. Two time intervals were identified, characterized by different intensities of radionuclide specific activity decrease. During the periods of 1989–1996 (1998), the specific activity of 137Cs in the studied plant species decreased by half in approximately 2 years. For the time interval of 2011(2012)–2021, the half-life period of 137Cs content in Potamogeton perfoliatus and Ceratophyllum demersum increased on average to 12 years. A tendency towards a slowdown in the rate of specific activity decrease was observed for Phragmites australis. During 1987–1996, the half-life period of maximum 137Cs specific activity in higher aquatic plants of Kaniv reservoir was 2.1 years. Thus, during the first decade after the accident, the rates of 137Cs content decrease in plants of Kyiv and Kaniv reservoirs did not differ. In 2000–2021, the rate of 137Cs specific activity decrease in Potamogeton perfoliatus and Ceratophyllum demersum of Kaniv reservoir corresponded on average to a half-life period of about 20 years. For Phragmites australis and Typha angustifolia, only a tendency to decrease in 137Cs activity was noted, corresponding to a half-life period of about 40 years. Over time, the half-life period of 137Cs specific activity in higher aquatic plants of Kyiv and Kaniv reservoirs increases, which is explained by the slowdown in the rate of decrease in volumetric activity of 137Cs in the waters of the Dnipro and Pripyat rivers. A model of 137Cs specific activity in higher aquatic plants of reservoirs for periods exceeding 20 years after accidental radionuclide entry into ecosystems of large plain reservoirs has been proposed. The parameters of the model describing the dynamics of 137Cs specific activity can be used for predictive assessments of 137Cs content in higher aquatic plants in the event of accidental radionuclide entry into ecosystems of large plain reservoirs.

Оценка загрязнения древесины и коры дуба 137Cs в зоне отчуждения Чернобыльской атомной электростанции

The results of studying the 137Cs contamination of English oak (Quercus robur L.) trunks in high-aged oak forests in the most radioactive polluted part of the Polesye State Radiation-Ecological Reserve territory located in the evacuation (exclusion) zone of the Chernobyl nuclear power plant are presented. The features of modern surface contamination soil by 137Cs in oak forest stands have been established, the factors that caused them have been identified: removal of research objects from the release site and conditions for deposition of radioactive fallout, as well as vertical redistribution of radionuclide in the soil over the time since the accident. The density of 137Cs soil contamination varies by types of oak forest. The current indicators of 137Cs accumulation in wood, bark and oak trunks, their changes by forest types, the relationship with the density of soil pollution and the distance to the disaster site are determined. A 2-3-fold excess of 137Cs oak bark contamination was found in comparison with wood, which is due to their morpho-physiological characteristics. Over the past 25 years, the wood and bark proportions of the relative contributions to the specific activity of 137Cs of the oak trunks have changed significantly. The decrease in the contribution of the bark to the specific activity of 137Cs in the trunk is due to a slowdown in the entry of radionuclide into it. The 137Cs distribution in oak wood by classes of growth and development of trees by Craft is shown. It was found that the average values of the radionuclide specific activity in standing and lying deadwood are 25-28 % lower than in the wood of living trees. The tendency of decreasing of 137Cs concentration in oak wood from the periphery to the center of the trunk has been confirmed. As of 2021, according to the sanitary standard of the Republic of Belarus for the content of 137Cs 1480 Bq kg-1, harvesting of oak wood could be allowed in 84 % of the surveyed stands, oak trunks with bark - in 72 %. The standard of 740 Bq kg-1 corresponded to oak wood in bark and without bark in 32 % of forest stands.

Radiation situation in the territory of the uranium legacy site in the Bambakai Valley (Transbaikal Territory)

The article presents the results of a study of the current radiation situation at the uranium legacy site located in the territory of the Bambakai Valley (Transbaikal Territory), formed in the period from 1973 to 1989 due to the discharge of mine water. During the radiation survey, the method of pedestrian gamma survey was used to measure the ambient dose equivalent rate. Soil sampling was carried out to study the radionuclide specific activities in the soil. The activity of gamma-emitting radionuclides in the samples was measured with a stationary gamma spectrometer. The activities of 210Po and 210Pb were measured after their radiochemical extraction from samples. It was found that the values of ambient dose equivalent rate in the territory of the valley varied over the wide range from 0.1 to 1.4 µSv/h in the areas under manmade contamination. The estimated average value of the gamma background for this place is 0.14±0.02 µSv/h. The specific activities of 238U, 226Ra, 235U, 210Pb and 210Po in the surface 10-cm soil layer at the site are from 10-40 times higher than the background values. The most part of radionuclides in the soil is in the acid-soluble form. Effective doses of the workers involved in hay harvesting in the area of the fallow land do not exceed 1.5 µSv/year. Doses of terrestrial environmental media (grass, earthworms) are 100 and more times lower than the safe level of exposure to biota.

РАДИАЦИОННАЯ ОБСТАНОВКА В РАЙОНЕ РАСПОЛОЖЕНИЯ РУДНИКА № 2 ЛЕРМОНТОВСКОГО ПРОИЗВОДСТВЕННОГО ОБЪЕДИНЕНИЯ «АЛМАЗ»

Purpose: Assessment of the current radiation situation around dumps of mine No. 2 of the Lermontov Production Association Almaz after remediation. Material and methods: The methods of pedestrian gamma survey using the portable spectrometric complex MKS-01A “Multirad-M”. Soil sampling was used to measure radionuclide specific activities. Activities of gamma emitting radionuclides were measured by a stationary gamma spectrometer of the CANBERRA Company. Activities of 210Po and 210Pb following radiochemical separation of these radionuclides were measured using the radiometric installation UMF-2000. Short-term measurements of radon EEC were carried out with aerosol alpha-radiometer RAA-20P2 Poisk. Results: After remediation, gamma ambient dose equivalent rate does not exceed 0,5 μSv/h at all dumps, with the exception of local areas around tunnels No. 9, 10 and 11. In the area around tunnel No. 9, gamma ambient dose equivalent rate reaches 0,55 μSv/h, in the area of tunnel No. 10–5 μSv/h and higher, and in the area of tunnel No. 11 – up to 0,9 μSv/h. In the areas around all tunnels, except for tunnel No.11, soil does not belong to solid radioactive waste. In a small area near tunnel No. 11, the content of radionuclides in the soil exceeds the criteria for classifying as solid radioactive waste. Radon EEC in the surveyed area generally did not exceed 30 Bq/m3. Increased values up to 200 Bq/m3 were registered in the area of tunnel dumps, the mouths of which were not fully isolated (tunnels No. 6, 7 and 10). Moreover, directly at the mouth of tunnel No. 10, radon EEC values reached 65000±11000 Bq/m3. Conclusions: At all surveyed remedied dumps, except for dumps of tunnels No. 10 and 11, the radiation situation in some areas does not meet the requirements established in the remediation project in accordance with the “Health Care Rules for the Closure, Conservation and Conversion of Enterprises for the Mining and Milling Radioactive Ores” and stay in these territories does not pose a hazard to the population.

Агрохимические аспекты реабилитации радиоактивно загрязнённых заливных лугов Брянской области

Natural fodder lands are a fodder base for livestock production in Bryansk region. The lands cover the area of 5500 km2, its greater part was contaminated with long-lived artificial radionuclides due to the Chernobyl accident. Therefore, there was a risk of contamination of the forage for dairy livestock with Cs-137 and its content in the grass would exceed the acceptable limit. Long after the Chernobyl accident the measures to remediate contaminated floodplains in Iput River in Novozybkovsky district of the Bryansk region for further use in feed production were examined. It was found that if Cs-137 contamination density exceeded 555 kBq/m2 the radionuclide content in the mass of air-dry wild grasses would be ≥5.5 times higher than the acceptable limit depending on a harvesting period. Due to the use of agrotechnical and organizational measures to improve the quality of radiation contaminated flood meadows the Cs-137 specific activity in air-dry cultivated grasses reduced by 10% as compared with the radionuclide activity in natural/wild grasses. The use of agrochemical measures for remediation of radiation contaminated flood meadows allowed to obtain air-dry masses of wild and cultivated grasses with the acceptable limit of Cs-137 radioactivity in fodders. The maximum effect was obtained when applying mineral fertilizers with a ratio of nitrogen to potassium as 1:2. Due to the use of correlation analysis it became made evident that the presence of nitrogen fertilizer increased Cs-137 specific activity in the fodder and there was the correlation between calendar years of the study and the amount of nitrogen fertilizers in soil. The correlation between the amount of nitrogen fertilizer in the soil and the specific activity of Cs-137 in the air-dry mass of natural and cultivated grasses during the years of 2003-2008 was strong and ranged from 0.76 to 0.85. In the study periods from 2009 to 2014, the impact of nitrogen fertilizer on the radionuclide specific activity in feed decreased regardless of the harvest period of natural and cultivated grasses. The correlation coefficient ranged from 0.38 to 0.58, the correlation strength was average. With the use of correlation analysis nitrogen fertilizers were found to increase the specific activity of Cs-137 in airdry grass mass, the correlation strength depends on calendar years of the study, it may be strong and average. Adding potassium fertilizer into soil negate the negative effect of nitrogen fertilizers. The use of radioactive floodplains as hay fields without the use of agrochemical measures is unacceptable. According to made calculations, the use of coarse fodder grown on radiation contaminated lands leads to milk contaminated with Cs-137 content that exceeds the limit established by standard.

Оценка радиационно-гигиенической обстановки в районе расположения судоремонтных предприятий в Камчатском крае

The objectives of the study are to examine the radiation and health physics situation in the area of ship repair enterprises servicing ships with nuclear power installation; to assess its possible impact on the environment and the population. Materials and research methods. The study of radiation and health physics situation on the territory was conducted by walking gamma survey using portable gamma spectrometric complexes MKS-01A "Multirad-gamma" and MKS-AT6101C. Gamma-spectrometric and radiochemical methods of analysis were used to determine the specific activity of man-made and natural radionuclides in environmental samples. Results of the study and their analysis. Practical medical and hygienic measures to study the radiation and health physics situation were carried out in 2019. It was found that the ambient equivalent dose rate in the areas of ship repair enterprises is at the level of regional values and does not exceed 0.12 μSv/h. Radionuclide specific activity in the soil of the surveyed areas does not exceed 4.5 Bq/kg — for 90Sr and 12 Bq/kg — for 137Cs, which does not exceed the established norms for unrestricted use of solid materials. Radionuclide content in the sea water samples taken in the area of closed administrative territorial unit Krasheninnikov Bay does not exceed on average: for 137Cs — 7 mBq/L, for 90Sr — 2.1 mBq/L. When comparing the results obtained with the official data on the radionuclide content in the water of Avacha Bay (90Sr up to 2.08 mBq/L at the annual average of 1.14 mBq/L), we may state that they are at the same level as the regional ones. Radionuclide content in bottom sediment samples varies within the following limits: for 137Cs — from 0.14 to 3 Bq/kg, for 90Sr — from 0.11 to 1.5 Bq/kg and is similar to the general values for soil samples. Thus, the radiation and health physics characteristics of the study area vary little and remain practically at the level of the results of studies conducted in 2014-2015. The content of man-made radionuclides in the samples of environmental objects is at the level of average values typical for the region. Potentially radiation-hazardous works carried out in 2019 at enterprises of closed administrative territorial unit Vilyuchinsk had no reliable radiation impact on the environment and population.

Long-term dynamics of radionuclide contamination formation in the industrial іchthyofauna of the Kaniv Reservoir

The aim the study is to determine the temporal parameters of the long-lived radionuclides specific activity decrease in the commercial fish species of the Kaniv Reservoir for the period 1987–2021. Rutilus rutilus, Scardinius erythrophthalmus, Blissa bjoerkna, Abramis brama, Pelecus cultratus (peaceful species) and Esox lucius, Stizostedion lucioperca (carnivorous species) were selected in the middle and lower parts of the reservoir in January 2021 to determine the current levels of radioactive contamination in the representatives of the commercial ichthyofauna of the Kaniv Reservoir. The specific activity of 90Sr and 137Cs was determined in the entire body of fish by conventional radiochemical and gamma-spectrometric methods. The analysis of the dynamic characteristics of the radionuclides content in the representatives of the reservoir ichthyofauna was carried out on the basis of the results of studies of 90Sr and 137Cs content in fish during 1987–2012 and their specific activity in the body in 2021. In 2021, the average specific activity of 90Sr in fish was 0.6–1.6 Bq/kg, 137Cs - 2.4–13.2 Bq/kg. According to the results of previous studies, the average specific content of 90Sr in the fish of the Kaniv Reservoir decreased by approximately 6.5 times - from 60 ± 30 to 9 ± 3 Bq / kg during 1987-1993, and by 2003 it decreased by another 5 times up to 1.8 ± 0.8 Bq / kg and did not exceed the values recorded in freshwater fish in Ukraine before the Chernobyl accident in 1979–1985. Consequently, during the period of 2003–2021 the levels of 90Sr content in fish from the Kaniv Reservoir remained virtually unchanged. Based on the data on 137Cs accumulation in various feeding types fish in the Kaniv Reservoir, time parameters describing a decrease in the element specific activity were determined. During 1987–2021 the rate of decrease in 137Cs content in peaceful and predatory fish did not differ significantly and amounted to 0.10 ± 0.01 year-1, the period of effective half-decrease was 6.7 ± 0.7 years. Analysis of long-term data made it possible to distinguish 2 periods during which the specific activity of 137Cs in the fish organism decreased at different rates. In 1987-2004, 137Cs content levels in peaceful fish decreased from 70 ± 22 to 6.1 ± 2.2 Bq/kg, in carnivorous species - from 202 ± 41 to 19.8 ± 7.6 B/ kg, i.e. approximately by 10–11 times, which corresponds to a half-decrease of about 6 years. In 2004–2021 the element content in peaceful fish decreased to 2.9 ± 0.7 Bq/kg, in predatory fish - to 7.3 ± 4.1 Bq/kg, that is, by another 2–3 times, which corresponds to a half-decrease of 12 ± 3 years. Thus, it was found that the rate of decrease in 137Cs specific activity in fish slows down over time. The obtained parameters will make it possible to predict with a high degree of accuracy the dynamics of the radionuclide contamination formation in ichthyofauna in the event of artificial radionuclides entering aquatic ecosystems as a result of emergency situations. Key words: Kaniv Reservoir, fish, radionuclides, longterm dynamics, rate of decrease.

ОСОБЛИВОСТІ РОЗПОДІЛУ 137Сs У КОМПОНЕНТАХ ЛІСОВОГО БІОГЕОЦЕНОЗУ СВІЖИХ БОРІВ УКРАЇНСЬКОГО ПОЛІССЯ

Вивчено особливості розподілу 137Cs у компонентах лісового біогеоценозу свіжих борів Українсь-кого Полісся. Щільність радіоактивного забруднення ґрунту на пробній площі становила 267±9,6 кБк/м2. Питома активність 137Cs у компонентах біогеоценозу відрізнялася на кілька поряд-ків, з мінімумом у глибинних горизонтах ґрунту (28–30 см шар – 40 Бк/кг) і максимумом у надземнійфітомасі окремих видів рослин (щитник шартрський – 85937 Бк/кг). Компоненти соснового дерево-стану можна розмістити в такий ряд за зменшенням величини питомої активності 137Cs: пагони >кора внутрішня > шпильки > кора зовнішня > гілки тонкі > гілки товсті > деревина, а для трав’яно-чагарничкового покриву характерний такий ряд: щитник шартрський > чорниця > верес звичайний> брусниця > плаун булавовидний > ортилія однобока > ожика волосиста. Моховий покрив характе-ризується вищими величинами питомої активності радіонуклідів порівняно з лишайниковим покри-вом, де епіфітні види лишайників мають менший вміст 137Cs, ніж епігейні. У сосновому біогеоценозіґрунтовий покрив утримує основну частку сумарної активності радіонуклідів (76,66 %), з них на лі-сову підстилку припадає – 14,24 %, а на мінеральні шари ґрунту – 62,42 %. На інші компоненти при-падає – 23,34 %, де сосновий деревостан та моховий покрив відповідно становлять 12,02 та11,04 %, а на підріст, лишайниковий та трав’яно-чагарничковий покрив припадає лише 0,28 %. Осно-вна частка фітомаси фітоценозу припадає на деревний ярус – 85,10 %, на моховий покрив – 14,48 %,а роль інших ярусів рослинності в цьому екотопі була незначною та становила 0,42 %. Розподіл су-марної активності 137Cs по компонентах значно відрізняється порівняно з розподілом фітомаси наодиницю площі. Так, максимальну частку валового запасу 137Cs утримує деревний ярус (51,49 %) тамоховий покрив (47,32 %). Частка решти ярусів незначна, становить 1,19 % і представлена у тако-му порядку за зменшенням утримуючої здатності радіонуклідів: трав’яно-чагарничковий покрив >лишайниковий покрив > підріст. У сосновому біогеоценозі ключовими компонентами в утримуванійздатності та інтенсивності біогеохімічного кругообігу радіонуклідів є лісовий ґрунт, деревний яруста моховий покрив.

Speciation of Radium-226 in the Components of Terrestrial and Aqueous Northern Taiga Ecosystems in a Former Radium Production Site

Abstract—The paper considers the content and geochemical mobility of 226Ra in surface waters, bottom sediments, and radioactively contaminated soils (podzolic and alluvial–soddy) of the northern taiga subzone in the area of former radium production site. It is established that the level or radioactive contamination and specific activity of geochemically mobile radium in the podzolic soil is higher, while its migration with surface waters is lower (0.03 Bq/L) than in the alluvial–soddy soil. The drainage waters of the latter are characterized by the maximum radium content (0.55 Bq/L), which is mainly concentrated in the suspended matter (98%) and humic acids (97%) fractions. In the river waters, radium is mainly accumulated in the suspended fraction and fulvic acid compounds. It is shown that under low-temperature and high-water current conditions and a weak sorption capacity of bottom material, the specific activity of the radioactive element in the riverine sediments in the zone of anthropogenic impact is higher than the average background value (0.3–1.8 against 0.2 mBq/g). Sedimentation of radionuclide in the geochemically mobile and weakly mobile species is most intense within contaminated sites. The radium content in the “carbonates”, “sesqui-oxides and -hydroxides” and, especially, “exchangeable” fractions extracted from soils was higher than in other fractions. A cumulative fraction of “water soluble”, “organic matter”, and “amorphous silicates” groups accounts for 0.4–3.7 and 1.6–7.4% of radionuclide content in the podzolic and alluvial–soddy soils, respectively, and was characterized by the predominance of “organic matter” fraction. The fraction of geochemically mobile radium is negatively correlated with its bulk specific activity (r = –0.81), which is noted as trend for bottom sediments. The contribution of insoluble residue in the radionuclide specific activity was 23.5–95.5 and 7.8–69.4% in the podzolic and alluvial–soddy oils, respectively.

Application of clusterization algorithms for building materials classification on radioactivity in R

The clusterization method of raw construction materials on their radioactivity with clusterization algorithms within statistical treatment environment and R analysis applied is handled in the paper. The authors make an emphasis on application of modern methods of raw construction materials radioactivity data treatment. Raw construction materials are evaluated on the basis of objective evidence, reflecting indices of specific activities and of inner natural radionuclides specific activity. As a result of net learning on the experimental data the authors acquire a cluster map provided with segmentation on the natural radionuclides effective specific activity. Consequently, both the criteria are established and the hitting of a raw material into the corresponding cluster is estimated. The application of a “decision tree” algorithm makes it possible to state rules according to which raw materials refer to these or those clusters. As opposed to traditional analysis methods, the applied technique of radioactivity estimation is based on quantitative characteristics. On the ground of the acquired results conclusions are made on a possibility and appropriateness of application of the said technique of analysis and classification of raw materials radioactivity data.

Radioactivity and Heavy Metals Concentration in Italian (Calabrian) DOC Wines

Wine is an alcoholic drink, largely used to accompany food, with a key role in the protective effects on cardiovascular diseases. This study was developed to investigate radioisotopes and heavy metal content of twenty red, rose and white Italian wines, belonging to controlled origin denomination (DOC) geographic areas of the Calabria region, south of Italy. High Purity Germanium (HPGe) Gamma Spectrometry was employed to evaluate anthropogenic (137Cs) and natural (40K) radionuclides specific activity. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to assess any possible heavy metals contamination by a comparison between Cu, Zn, Pb, B, As and Cd concentrations with the limits set by the Italian Legislation. Calculated annual effective doses due to the ingestion of investigated samples are under allowable levels (1 mSv/year), thus excluding the risk of ionizing radiation effects on humans. Regarding to the metals concentration, experimental results show that they are lower than the contamination threshold values, thus excluding their presence as pollutants.

Radiation-hygienic assessment of the concentration and distribution of <sup>90</sup>Sr and <sup>137</sup>Cs in ichthyofauna of the Ob’-Irtysh river system

The aim of the work is the radiation-hygienic assessment of 90Sr and 137Cs content in fish of the Ob-Irtysh river system and the study of the basic laws of the radionuclides accumulation in the ichthyofauna of these rivers. To perform this task, long-term results of radioecological studies of fish from the Techa, Irtysh and Ob rivers for the period 2004-2016 were used. Fish as a food product was evaluated according to two criteria: a) permissible levels of radionuclides specific activity (SanPiN 2.3.2.1078-01); b) using the indicator of conformity В and uncertainty of its definition ΔВ (GOST 32161-2013 and GOST 32163-2013). It is shown that a higher content of radionuclides is observed in the ichthyofauna of the Techa river (1379.1 Bq/kg for 90Sr and 41.9 Bq/kg for 137Cs). On the Ob and Irtysh rivers, the average specific activity of radionuclides in fish was significantly lower and slightly changed during the surveyed area: for 90Sr in the range of 6.0 ÷ 8.1 Bq/kg (mean 6.8), for 137Cs – 0.6 ÷ 1.9 Bq/kg (mean 1.3). Assessment for compliance with radiation safety criteria using the indicator of compliance and its uncertainty (В+ΔВ) confirmed the unsuitability of use for food purposes by the radiation factor of all studied fish species from the Techa river (45÷55 >1). Fish from all other studied areas of the Ob-Irtysh river system can be used for food without restrictions (0,06÷0,53 < 1). The distribution of 90Sr and 137Cs in the ichthyofauna of the Ob-Irtysh river system part over a 2400 km is presented in the form of empirical regression models. The models describe a sharp decrease in the radionuclides specific activity in fish in the Techa and Iset rivers by two orders for 90Sr (from 2000 to 20 Bq/kg), and by one order for 137Cs (from 40 to 2 Bq/kg). With a high degree of reliability (R2>0.86 for 90Sr and R2>0.92 for 137Cs), the presence of power relationships between the content of radionuclides in the ichthyofauna and their content in water was shown, with adequacy confirmed by Fisher’s F-criteria. This can be used for a preliminary assessment of the radionuclides level in fish based on the results of measurements of the average annual concentrations of these radionuclides in water.

CONTENT OF URANIUM ISOTOPES IN THE GROUNDWATER SUPPLIES USED FOR POPULATION OF LENINGRAD REGION AND ST-PETERSBURG

The aim of the study was to obtain 234U and 238U specific activity in the water of groundwater supplies of Leningrad region and St-Petersburg and to estimate the possibility of their using from the point of view of radiation and chemical toxicity of the main dose-forming uranium isotopes usually containing in the underground waters. The study was focused on the water of functioning and exploratory groundwater supplies concerning the safety of water consumption taken into account radiation and chemical index. Data on the levels of natural uranium isotopes specific activity in the sources under investigation was obtained using radiochemical analysis with the subsequent alpha-spectrometric measurement of the counting samples. 58 samples of natural groundwater were analyzed during the period from February of 2011 till the May of 2017. The volume of the native water samples was from 10 l to 30 l, measuring time for each counting sample was 6 – 12 hours, which allowed measuring the radionuclides specific activity value at the level of 0.0002 Bq/kg. The values of 238U specific activity varied within 0.0002 Bq/kg – 0.06 Bq/kg, the average value was 0.007 Bq/kg. The values of 234U specific activity varied within 0.0006 Bq/kg – 0.111 Bq/kg, the average value was 0.013 Bq/kg. The average value of the specific activities ratio 234U/238U was 2.12 and the range of this value was 1.00 – 8.00. The results of carried out investigations demonstrates that the specific activity values of uranium isotopes could differ more then by an order of magnitude even in the borders of same aquifer of a small settlement. 238U specific activity value does not exceed 0.02 Bq/kg and 234U specific activity value does not exceed 0.04 Bq/kg for the vast majority of analyzed sample. The value of the ratio 234U/238U was 1.00 – 4.00 for 98.3% of analyzed sample. It is possible to conclude with a high probability that the water from the groundwater supplies of Leningrad region and St-Petersburg is safe for consumption by population concerning 234U and 238U content as from the point of view of radiological factor, so from the point of view of chemical toxicity.

Evaluation of radiological impacts from NORM: a case study

In this article an evaluation of the radiological impact for a TENORM (Technologically Enhanced Naturally Occurring Radioactive Materials) waste, coming from a landfill of one of the Italian reclamation Sites of National Interest (SIN), is made in order to assess any possible radiological hazard for the population. The natural radioactivity investigation was performed by using High Resolution Gamma-ray Spectrometry (HRGS) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), to determine activity concentrations of U-nat (238U, 234Th, 234−mPa, 234U, 235U and 231Th), Ra-226+ (226Ra, 222Rn, 218Po, 214Pb, 214Bi and 214Po), Ra-228+ (228Ra and 228Ac) sub-chains radionuclides and 40K, and to compare them with clearance levels (CL) reported in the European Commission “Radiation Protection 122-part II”. The Sum Index (SI), i.e. the sum of the radionuclides specific activity normalized to the respective CL, was calculated, in order to investigate about the compliance of the analyzed waste according to the limit set in terms of individual effective dose for the population.

POTENTIALLY POSSIBLE POPULATION EXPOSURE DOSES DUE TO MINERAL NATURAL MEDICAL WATER CONSUMPTION

Mineral natural table, medical-table and medical water is usually characterized by enhanced mineralization, so annual consumption of such water for drinking and cooking is much lower than standard water consumption of adult population. The limitation of population exposure due to mineral natural table and medical-table water could be achieved by the implementation of limitation of their consumption. The aim of the investigation is to estimate potentially possible population exposure doses from mineral natural medical water consumption on an example of the water which is used for drinking therapy in the complex of sanatorium health resort treatment of patients in one of the sanatoriums of Saint-Petersburg. The data on mineral medical water radionuclides specific activity values used for patients exposure doses estimation was obtained during implemented radiochemical analysis carried out using the techniques developed in the Institute of Radiation Hygiene. Obtained results of the investigations and their analysis demonstrated that potentially possible patients’ maximal annual effective exposure doses due to implementation of mineral natural medical water for drinking therapy in the complex of sanatorium health resort treatment will not exceed definitely the reference dose level, recommended by WHO, equal to 0.1 mSv/year because of a low amount of water consumption prescribed by a physician. It is clear unreasonable to set limitations on natural radionuclides content in mineral medical water because patients take it as a medicine according to physician prescribing and the consumption of such water is connected with their therapy properties. Principle of justification of the procedures appointment has to be applied when the course of mineral medical water treatment is prescribed. The essence of the principle is to compare therapy (medical) benefits as a result of treatment with the damage to health as a result of radiation exposure. It is necessary to estimate the effective internal exposure doses due to mineral natural medical water consumption for different age groups of population for the process of justification of therapy procedures.

An investigation of ionizing radiation dose in a manufacturing enterprise of ion-absorbing type rare earth ore

Objective: To investigate radioactive source term dose monitoring and estimation results in a manufacturing enterprise of ion-absorbing type rare earth ore and the possible ionizing radiation dose received by its workers. Methods: Ionizing radiation monitoring data of the posts in the control area and supervised area of workplace were collected, and the annual average effective dose directly estimated or estimated using formulas was evaluated and analyzed. Results: In the control area and supervised area of the workplace for this rare earth ore, α surface contamination activity had a maximum value of 0.35 Bq/cm2 and a minimum value of 0.01 Bq/cm2; β radioactive surface contamination activity had a maximum value of 18.8 Bq/cm2 and a minimum value of 0.22 Bq/cm2. In 14 monitoring points in the workplace, the maximum value of the annual average effective dose of occupational exposure was 1.641 mSv/a, which did not exceed the authorized limit for workers (5 mSv/a) , but exceeded the authorized limit for general personnel (0.25 mSv/a) . The radionuclide specific activity of ionic mixed rare earth oxides was determined to be 0.9. Conclusion: The annual average effective dose of occupational exposure in this enterprise does not exceed the authorized limit for workers, but it exceeds the authorized limit for general personnel. We should pay attention to the focus of the radiation process, especially for public works radiation.

LOW-INTENSITY RADIOACTIVE ANOMALIES IN ARKHANGELSK CITY

The goal of the research is to find out the main low-intensity radioactive anomalies as the main probable source of human light irradiation in Arkhangelsk city; give an objective estimation of radiation risks and potential health damage of the local population. Avtogamma-spectrometric method, using a mobile radiation monitoring system RS-700 was firstly used in the city. It allows to measure both natural and artificial radionuclides in real time geo-referenced. Ground gamma survey method with geological prospecting scintillation radiometer SRP-88H has been used for specification of obtained results. Soil sampling has been selected in each city block with further definition of radionuclides specific activity in the gamma spectrometer counting sample "Progress". A unique set of data on the radioactive level and the specific activity of 137Cs, 40K, 232Th, 226Ra in the soil have been collected as a part of the radio-ecological study. Nine local low-intensity anomalies have been revealed and their genesis has been set. The comparative comprehensive assessment of low doses ionizing radiation on human health has been done. Possible ways of further medical and environmental research in the field of oncological diseases and radioactivity study in the city of Arkhangelsk have been planned.

137Cs allocation in forest ecosystems of Ukrainian Polissya

It is determined that at present the largest share of the total activity of radionuclides in biogeocenosis is concentrated in soil: 86.27% — in wet pinewoods; and 98.88% — in wet sudubravas. It was determined that migration of radionuclides to woody plants in wet sudubravas is considerably less than that observed in wet bory. Thus, in 2012, the forest stand in wet sudubravas contained only 0.12% of 137Cs total activity in biogeocenosis. In wet pinewoods this ratio is much higher — 7.48% (by 62.3 times). The analysis of the distribution of the total activity of 137Cs in phytocenosis of the studied types of forest conditions showed that the highest radionuclide content is observed in the forest stand. 137Cs content in the plants lower layer is much lower. As it has been already mentioned, the value of the radionuclide specific activity in these plants is higher than in tree organs and parts of trees. But the mass of the tree layer is much bigger than the mass of any layer of plants located lower. Thus, the comparison of the mass of plants and the specific activity of the radionuclides in plants of each plant layer makes it possible to give preference to the first index in the distribution of the total activity in phytocenosis.

Therapeutic application of CCK2R-targeting PP-F11: influence of particle range, activity and peptide amount.

BackgroundTargeted radionuclide therapy with high-energy beta-emitters is generally considered suboptimal to cure small tumours (<300 mg). Tumour targeting of the CCK2 receptor-binding minigastrin analogue PP-F11 was determined in a tumour-bearing mouse model at increasing peptide amounts. The optimal therapy was analysed for PP-F11 labelled with 90Y, 177Lu or 213Bi, accounting for the radionuclide specific activities (SAs), the tumour absorbed doses and tumour (radio) biology.MethodsTumour uptake of 111In-PP-F11 was determined in nude mice bearing CCK2 receptor-transfected A431 xenografts at 1 and 4 h post-injection for escalating peptide masses of 0.03 to 15 nmol/mouse. The absorbed tumour dose was estimated, assuming comparable biodistributions of the 90Y, 177Lu or 213Bi radiolabelled peptides. The linear-quadratic (LQ) model was used to calculate the tumour control probabilities (TCP) as a function of tumour mass and growth.ResultsPractically achievable maximum SAs for PP-F11 labelled with 90Y and 177Lu were 400 MBq 90Y/nmol and 120 MBq177Lu/nmol. Both the large elution volume from the 220 MBq 225Ac generator used and reaction kinetics diminished the maximum achieved 213Bi SA in practice: 40 MBq 213Bi/nmol. Tumour uptakes decreased rapidly with increasing peptide amounts, following a logarithmic curve with ED50 = 0.5 nmol. At 0.03 nmol peptide, the (300 mg) tumour dose was 9 Gy after 12 MBq 90Y-PP-F11, and for 111In and 177Lu, this was 1 Gy. A curative dose of 60 Gy could be achieved with a single administration of 111 MBq 90Y labelled to 0.28 nmol PP-F11 or with 4 × 17 MBq 213Bi (0.41 nmol) when its α-radiation relative biological effectiveness (RBE) was assumed to be 3.4. Repeated dosing is preferable to avoid complete tumour receptor saturation. Tumours larger than 200 mg are curable with 90Y-PP-F11; the other radionuclides perform better in smaller tumours. Furthermore, 177Lu is not optimal for curing fast-growing tumours.ConclusionsReceptor saturation, specific radiopharmaceutical activities and absorbed doses in the tumour together favour therapy with the CCK2 receptor-binding peptide PP-F11 labelled with 90Y, despite its longer β-particle range in tissue, certainly for tumours larger than 300 mg. The predicted TCPs are of theoretical nature and need to be compared with the outcome of targeted radionuclide experiments.

Research on Removing Radioactivity Minerals Form Titanium Rough Concentration of Haibing

Titanium rough concentrate in Haibing contains ilmenite, rutile and other valuable minerals, and also radioactive mineral monazite. Ore minerals contain 42.08% of TiO2 and 4.92% of ZrO2. Radionuclide specific activities results shown that intensity of radioactivity of 226Ra, Th and 40K are 2142.2Bq/kg, 8964.2Bq/kg and 724.72Bq/kg respectively. Through integration process of shaking table-weak magnetic-dry high intensity magnetic-electric separation, qualified titanium concentrate, azurite concentrate and monazite were obtained, which recovers the voluble minerals at maximal extent.