Total Beta Activity Research Articles

Variation of total alpha and beta activities and Rn-222 concentrations in the water supply system of an Italian volcanic region: How safe is tap water for human consumption?

Total alpha and beta activities and Rn-222 concentrations were determined in water from different sections of seven aqueducts belonging to the water supply system of Campania region (Italy), known worldwide for its volcanism. Statistical analysis was performed on data to account for their variability across the aqueduct sections, and results were discussed considering the geology of reservoirs, the potential mixing processes occurring along the pipe network, the building/constituting materials of the aqueduct sections, and the integrity of the infrastructure. Guidelines proposed by Italian and international regulation entities were considered to determine if total alpha and beta activities and Rn-222 concentrations found at the taps of the different aqueducts should be considered detrimental to public health. Based on a deterministic and a stochastic approach, a health risk assessment was also tested for Rn-222, assuming direct ingestion and showering as potential exposure pathways. Results showed that applying guidelines returned an absence of hazard, whereas risk assessment returned a high probability of exposure to unacceptable Rn-222 doses for some aqueducts. Beyond the usefulness of obtained results to plan actions to improve the safety of drinking water in Campania, our outcomes represent a warning for bodies dealing with public health at any level: the use of guidelines can bring an underestimation of the risks exerted by the exposure to Rn-222 on human health. Further, using a probabilistic approach in risk assessment accounting for uncertainty can favor risk forecasts based on more “realistic” scenarios.

The first findings of the study of the territory of the water basin of the Kapshagai Reservoir. Uranium isotope distribution

This article presents the first results of the examination of environmental objects (water, coastal soil, bottom sediments) of the Kapshagai Reservoir water basin. Radionuclide composition of selected samples by alpha-, gamma spectrometry and total alpha- and beta-activity were determined. It has been established that in some water samples, the total alpha activity exceeds the standard of the Republic of Kazakhstan for drinking water, the total beta activity does not exceed the standard. Presents the results of uranium-238, uranium-234, uranium-235 activities and also gives the ratio of uranium-234 to uranium-238 activities, which is an important indicator of water contamination by this element.

Аналіз радіаційного стану в санітарно-захисній зоні та зоні спостереження дослідницького ядерного реактора ВВР-М Інституту ядерних досліджень НАН України у 2021 р.

The results of the analysis of the radiation state of environmental objects in the sanitary protection zone (SPZ) and surveillance zone (SZ) of the research nuclear reactor (RNR) WWR-M of the Institute for Nuclear Research of the National Academy of Sciences of Ukraine (INR) for 2021 are analyzed and compared with the data for previous years (from 2016 to 2020). The levels of total beta activity of sedimentary dust and atmospheric precipitation and wastewater from the main reservoirs of INR, the concentration of beta-active aerosols in the surface layer of atmospheric air, as well as the content of 137Cs radionuclide in soil and vegetation samples, were studied. The research was conducted in the laboratory of the Center for Ecological Problems of Atomic Energy of INR. The obtained results show that in 2021 there was no excess of the values of controlled parameters compared to previous years. There was also no significant difference in the specific activity of the radionuclide 137Cs in soil and vegetation samples from SPZ and ZS. Studies conducted in the period from 2016 to 2021, allowed to accumulate significant factual material on the radiation situation in the sanitary protection zone and surveillance zone and to substantiate the conclusion about the absence of man-made radioactive contamination of the environment due to the operation of RNR WWR-M of INR of NAS of Ukraine.

Радіаційно-гігієнічний моніторинг у районі Запорізької АЕС в умовах загрози радіаційної небезпеки

Objective: To assess the results of monitoring radiation indicators of the state of the environment in the Zaporizhzhia region under the threat of a radiation accident at the Zaporizhzhia NPP in order to make decisions regarding the use of countermeasures. Materials and methods: As a result of the analysis of long-term observations, indicators of radioactivity in the event of a radiation accident were determined. More than 21,000 measurements of the gamma background of the territory were carried out in 13 settlements of the Zaporizhzhia region. The dosimetry method was used to measure the power of the equivalent dose. The radiometric method was used to study the total radioactivity of drinking water from the water supply network. 21 samples were taken. The study of the total beta activity of atmospheric precipitation and settling dust was carried out by the sedimentation method. A total of 34 samples were examined. Results: As a result of the conducted research, it was recorded that the radiation component in the territory of the region did not change – gamma background levels remained within the range of long-term observations of 10-12 μR•h-1. It was established that the total alpha and beta activity of drinking water meets the requirements of the current legislation. The results of the studies of atmospheric sediments and settled dust show that there is no increase in the total beta activity in the atmosphere compared to the average long-term indicator observed in the period before 1986.

Накопление радионуклидов в рыбе из рек северо-западного сектора российской Арк­тики

The article presents the analysis of the radionuclide content in fish (perch — Perca fluviatilis L., pike — Esox Lucius L.) living in the rivers (Mezen, Nes and Pechora) of the northwestern sector of the Arctic zone of Russia. In one of the rivers of the study region (the Nes River in the Nenets Autonomous Area), the researchers have revealed the presence of technogenic radionuclides Cs-137 and Sr-90. To assess the distribution of these radionuclides in the fish body, they divided the selected fish samples into separate biological systems: muscle tissue, bone tissue, heads, entrails, a mixture of skin, scales and fins. The largest amount of Cs-137 is contained in the fish muscle tissue (more than 50% of the total radionuclide activity). The greatest amount of Sr-90 is contained in a mixture of skin, scales, fins (47%) and heads (33%) of river perch, while this radionuclide is absent in pike samples. There is a small content of Sr-90 in the bone tissue of river perch. In the absence of other technogenic short-lived radionuclides, the likely reason for the presence of Cs-137 and Sr-90 in the fish of the Nes River is a radioactive trace that appeared during nuclear tests on the Novaya Zemlya archipelago. The main dose-forming radionuclide in the selected fish samples was natural K-40. Its content for pike is estimated at 92% of the total beta activity, for river perch — 86%. The main content of this radionuclide falls on muscle tissue (about 50% for pike and river perch). According to the research results, it is noted that the levels of radioactivity in fish from the Nes River do not exceed the sanitary and hygienic standards established in the Russian Federation in the field of food safety and do not pose a significant radiological risk to the population.

Stages of radiation monitoring on the territory of the Tula region affected in consequence of the Chernobyl NPP accident

More than half of the Tula oblast territory was contaminated following the accident at the Chernobyl nuclear power plant. This article describes the stages of radiation hygiene monitoring of objects in the habitat in the Tula region impacted by radioactive contamination. Information is given on changes in radioactively contaminated areas at different periods after the accident. An assessment is made of the radiological situation at the initial “iodic” period of the accident, the subsequent “cesium” period, and at the current stage. A description is given of work done by the oblast’s state sanitary and epidemiological service based on radiation monitoring results for reducing the radiation exposure of the population at different stages of supervision. Information is supplied on high levels of gamma background up to 35 mkSv/h during the “iodic” period. Tabulated data are supplied on exceeding the tentative maximum permissible level of iodine-131 content in dairy products produced in Plavski district, the most contaminated area in the region. Data are given on laboratory tests on food products for total beta activity in 1986-87 and the frequency of exceeding the permissible level of cesium-137 content during 1986. The above permissible content of radionuclides in food products was registered only in 1986 due to surface contamination of plants, while in wild mushrooms this took place as late as 2004. Currently, the proved content of cesium-137 and strontium-90 in food products is determined only by the radio-chemical method. A table is supplied showing results of radio-chemical research on major dose contributing food products from 2010 to 2021. The article supplies a table with numeric values of annual average effective doses of radiation sustained by the population of settlements located in the Chernobyl radioactively contaminated zone during 1986 through 2021. The dose of the population’s exposure to the Chernobyl radiation since 1994 does not exceed 1 mSv/year. In 2021, the population’s annual effective dose in 98.3% of settlements amounted to less than 0.2 mSv/year.

Control quality measurements of alpha and beta counter with low back-ground ALBA 2000 v.2.5.6.

The article provides a systematic approach to quality control of measurements of total alpha-and beta-activity using a counter with a low background ALPHA / BETA COUNTING SYSTEM ALBA (mod. ALBA / LLAB) and software ALBA 2000 v.2.5.6. The purpose is to determine the compliance of these objects with the requirements of regulatory documentation. The spectrometry method is based on the physical concentration of radionuclides from the sample volume, measuring the rate of alpha, and beta radiation of the obtained dry residue of the sample, comparing the sample count rate with calibration values of activity, and calculating the total alpha, beta activity of the sample. The primary means of testing is a counter with a low background ALPHA / BETA COUNTING SYSTEM ALBA 200, the lower limit of measurements of the alpha activity, which is 0.02 Bq/l, and beta activity of 0.1 Bq/l, the relative random uncertainty of the measurement result is 60 % with a confidence level P = 0.95. The efficiency of registration on the alpha channel of 43 %, background on the alpha channel of 0,11 imp./min, for a measurement time of 60,000 s, the efficiency of registration on the beta channel of 30 %, background on the beta channel of 1,9 imp./min, for measurement time 60000 s. As a comparison sample for calculating total alpha activity, a sample with alpha radiation, 241Am (geometry 2π), is used. To calculate the total beta activity, a sample of beta-emitter of potassium sulfate with radionuclide is used at 40K (geometry 2π). The weight of the counting sample ranges from 200 to 1000 mg. The activity values are calculated automatically, using the software ALBA 2000, v.2.5.6. Measurement of the total activity of radionuclides in counting samples using the method should be performed only in calibrated geometries. At the same time, the safety requirements, personnel qualifications, and test conditions must be met. Quality control of measurements in the alpha, beta counter ALBA-2000 v.2.5.6. It is carried out in qualitative and quantitative ways.

Оценка «нулевого» радиационного фона территорий населенных пунктов Туркестанской области, расположенных вблизи площадки для строительства АЭС Республики Узбекистан

The construction of a nuclear power plant in the Republic of Uzbekistan actualizes measures for the radiation safety of the population and territories of Kazakhstan. The aim of the study was to assess the radiation situation in the settlements of the Turkestan region located near the impact zone of the nuclear power plant. The investigation includes measurements of ambient equivalent dose rates of gamma radiation, equivalent to the equilibrium volumetric activity of radon and thoron in residential buildings, establishing the total alpha and beta activities, and measuring the specific activity of radionuclides in water soil and food samples. In soil samples taken from the villages of Zhetysay and Zhyly-su, the specific activity of 232Th is 2 times higher than the national average. The total alpha activity of drinking water samples from the village of Zhyly-su is 1,5 times higher than the maximum permissible concentration. The concentration of artificial (137Cs, 90Sr) and natural radionuclides (226Ra, 232Th) in food is within the normal range. Obtaining preliminary results of the research will make it possible to assess the predicted radiation doses for various age groups of the population, and to develop preventive measures during the operation of a nuclear power plant.

The status and trends in radioactive contamination of groundwater at a LLW-ILW storage facility site near Sosnovy Bor (Leningrad region, Russia)

The article presents results of field studies at a site of radioactive waste storage and disposal facilities (the so-called LD RosRAO site, Sosnovy Bor, Leningrad region, Russia). The objective of the study is to overview the history and occurrence of groundwater contamination to answer the question whether the radioactive plume is historical (formed due to accidents, which happened at the beginning of the operations with the radioactive waste) or the release of radioactive solutions to groundwater is still occurring. The main method used to study the evolution of radioactive contamination is to analyze long-term observations of tritium, total alpha, and total beta activities in groundwater samples. The role of the hydrogeological conditions of the site, such as flow parameters, groundwater flow pattern, inter-aquifer downward groundwater leakage, and water-table fluctuations, in the evolution of contamination plumes has also been analyzed. In the field investigations, the integrity of the storage buildings to potential leaks was confirmed by different indirect methods. It was concluded that there is currently no significant release of radioactive components into groundwater at the LD RosRAO site and that the present conditions correspond to the stage of rehabilitation of the groundwater environment.

Assessing the natural and anthropogenic radionuclide activities of the Pechora River estuary: Bottom sediments and water (Arctic Ocean Basin)

This paper studies the activity of natural and technogenic radionuclides in bottom sediments and surface water of the Pechora River estuary, which is the largest Arctic river within the European part of Russia. The relevance of conducting radioecological studies of this region is associated with active oil and gas activities in the Pechora basin and the presence of potential sources of radiation hazard. The average activities of 137Cs, 226Ra, 232Th, and 40K in bottom sediments were 0.16, 18.72, 13.36, and 373.59 Bq·kg-1, respectively. The average activity of 226Ra in the bottom sediments of the Pechora delta was two times higher than in other rivers of the Arctic basin of the European part of Russia, which is associated with oil and gas activities that are carried out in the Pechora basin. This is due to the fact that the decay products of uranium are the main by-products of oil and gas production. The specific activity of technogenic 137Cs in bottom sediments of the Pechora River delta was low and did not exceed 2.2 Bq·kg-1. We did not detect any radioactive 90Sr in bottom sediments. The low 137Cs activity in the bottom sediments of the Pechora delta was associated with both the larger granulometric composition of the sediments in comparison with the estuaries of the Siberian rivers, and with low concentrations of 137Cs in the terrigenous material (soil) entering the river from the catchment area. This was due to the low levels of 137Cs contamination in the soil of the Pechora river basin. We did not find any negative radiation effects of the underground nuclear explosion “Pyrite” carried out in the northern part of the delta, since there were no other technogenic radionuclides. The values of the radionuclides 3H, 137Cs, 226Ra, 232Th and 40K, as well as the total alpha activity in the surface waters of the Pechora River delta, turned out to be below the detection limit. In surface waters, we were able to determine only the total beta activity, which varied over a range from 19.6 to 59.6 Bq·m-3 with an average value of 33.9 Bq·m-3, which was significantly lower than the radiation safety standards. The values of the radiation hazard parameters were below the world average levels and were not significantly hazardous to the health of people living in the area of the Pechora River delta. We concluded that at present, in the Pechora River delta, there are pastures for reindeer with low levels of natural and man-made radioactivity. These conducted studies are the source material in a series of comprehensive studies of the current radioecological state of the tundra territories of the European part of Russia.

До сплеску активності 137Cs в повітрі під об’єктом «Арка» 17 жовтня 2019 р.

The construction of a New Safe Confinement (NSC) is one of the main stages in the transformation of the Chornobyl nuclear power plant 4th power unit into an ecologically safe system. On the one hand, this system is designed to ensure the safety of personnel, the population and the environment, on the other — to allow safe work with the remnants of the unit. At the same time, the project allows quite high levels of bulk activity of radioactive aerosols inside the NSC — up to 210 Bq/m3 for total β-activity. The sharp increase in the volumetric air activity, observed on October 17–19, 2019 in a number of rooms of the Shelter object and in the space under the “Arch” object in the absence of a burst of activity outside these objects, can be considered as a successful kind of spontaneous test of the NSC isolation systems. The chronology of the dynamics of volume activity according to the act of official investigation of the precedent is given. The results of studies of aerosol filters exposed in the near zone of the Chornobyl NPP before and after the burst of activity in the air under the “Arсh” object are presented. Autoradiograms of fragments of these filters demonstrate a significant (≈2 orders of magnitude) increase in the number of hot particles immediately after the fall of the concrete fragment of the floor in the room 402/3. The analysis of features of the hot particles after the collapse indicates a significant contribution to the total activity of a large number of low-activity particles (0.005÷5 Bq), and the low 137Cs/241Am ratio that indicates their fuel nature. Based on the assumption about the fuel nature of hot particles, their minimum possible aerodynamic diameters were calculated, which are in the range 2.91<d<36.7 μm, which does not exclude the presence of smaller hot particles on the filter that are not visible using this method. The contribution of particles with aerodynamic diameters less than 10 μm, determined using the impactor, did not exceed 20% of the total beta activity of the aerosol.

Radioactivity of Bottled Water from Trade Network in Kyiv

In 2018-2019, we examined the radioactivity of 40 samples of bottled water of popular brands produced both in Ukraine and abroad, which were purchased in one Kyiv supermarket. The first stage of the study provided for the identification of total alpha and total beta activities. In the case of excessing their regulated values, we proceeded to the determination of the content of radium-226 and natural mixture of uranium isotopes. The study results evidenced that total alpha and total beta activities of low mineralization water do not exceed the regulated values. Total alpha activity exceeded the regulated value of 0.1 Bq/l ten times in specific cases and total beta-activity exceeded the value of 1.0 Bq/l almost three times for the majority of high mineralization water brands.
 The results of measuring total alpha and total beta activities depending on time elapsed from the moment the sample was prepared to the start of the measurements showed an increase in the alpha activity over time is typical for individual water samples, which indicates the accumulation of radioactivity from radium-226 decay products. However, the results of measuring the activity of radium-226 and a natural mixture of uranium isotopes did not reveal cases of exceeding regulated levels, which allows considering water of all brands suitable in terms of radionuclide content.
 Assessment of radiation doses from consumption of bottled water containing the measured values of radium-226 and natural mixture of uranium isotopes did not reveal exceeding regulated value of 0.1 mSv/year. Only one bottled water brand was an exception, since the estimated radiation dose for it was 0.2 mSv/year for the category of children aged 12 to 17 years with 98 % of its value due to radium-226. Such a radiation dose value was received assuming an annual consumption of 1.5 liters per day.

Практичне використання радіаційних параметрів якості питної води: настанови міжнародних організацій та український досвід

The analysis of the documents of the authoritative international organizations and scientific works was carried out from the point of view of the development of the strategy for ensuring the radiation quality of drinking water. The radiation parameters of the quality of drinking water, the interpretation of monitoring results by screening and recommended levels, the value of the individual dose criterion, as well as algorithms for establishing the frequency of monitoring of the radiation parameters of drinking water were considered. Objective: We analyzed the documents of reputable international organizations and scientific works in terms of the development of the strategy for ensuring radiation quality of drinking water and the features of the practical application of the parameters of water radiation quality in the world and Ukraine. Methods: bibliographic, analytical. Materials: We performed the analysis of the documents of international organizations (WHO, IAEA, ICRP, UNSCEAR), as well as scientific publications on the radiation quality of drinking water in the light of the experience in measuring the content of drinking water radionuclides at the territory of Ukraine. Results: Materials of the international documents and scientific publications demonstrate that the assessment of radiation quality of drinking water requires a balanced analysis. In some cases, based on the results of only one determination of the total alpha and total beta activity, it is impossible to draw an unambiguous conclusion about the suitability or unsuitability of drinking water for consumption. Taking into account the geological heterogeneity of the territory of Ukraine, in order to obtain sufficient data on the radioactivity of groundwater, it is necessary to conduct extensive screening studies of the radiation quality of water in the regions of the country with the involvement of geological and monitoring services, local authorities.

Study using Vetiver grass to treat radioacitve pollution at Sin Quyen copper miner area, Lao Cai Province

The article introduces the research results of using Vetiver grass in radioactive environment treatment (water waste, mud waste) in Sin Quyen copper mine area, Lao Cai province. After 30 days, uranium absorption efficiency reached 77.4% and thorium 83.5%, the total alpha and beta activity of the water dramatically declined, alpha treatment efficiency reached 95.3% while beta treatment efficiency reached 93.7%. The model of radioactive pollution treatment by Vetiver showed high efficiency, simple operation. Therefore, it is very promising to apply the treatment of radioactive sludge, radioactive waste sludge in the process of exploiting and processing Sin Quyen copper ore in particular, the areas of radioactive mineral mining in general.

Activity concentrations of 131I and other radionuclides in cow's milk in Belarus during the first month following the Chernobyl accident

The accident at the Chernobyl nuclear power plant (NPP) in Ukraine on April 26, 1986 led to a considerable release of radioactive material resulting in environmental contamination over vast areas of Belarus, Ukraine and western Russian Federation. The major health effect of the Chernobyl accident was an increase in thyroid cancer incidence in people exposed as children and adolescents, so much attention was paid to the thyroid doses resulting from intakes of 131I. Because cow's milk consumption was the main source of 131I intake by people, it was important to measure the 131I activity concentrations in cow's milk to calculate, or to validate, the thyroid doses to the exposed population. Almost 11,000 measurements of total beta-activity in cow's milk were performed using a DP-100 device during the first month after the Chernobyl accident in the most contaminated regions of Belarus. Using an ecological model and calibration coefficients for the DP-100 device the activity concentration of 131I in cow's milk was derived as well as the activity concentrations of the other radiologically important radionuclides, namely 134Cs, 137Cs, 89Sr and 90Sr. The activity concentrations of other radionuclides, such as 90Y, 132Te, 132I, 133I, 136Cs, 140Ba, 140La, 141Ce and 144Ce, in cow's milk were also estimated and were shown to be of minor importance. The concentrations of 95Zr, 95Nb, 103Ru and 106Ru in cow's milk were negligible. The data obtained in this study were validated by comparing derived 131I and 137Cs concentrations in cow's milk with gamma-spectrometry measurements performed in milk produced in the same location close to the same date. The results of this study were essential to assess and validate the radiation doses received by the subjects of epidemiological studies related to the health consequences of the Chernobyl accident.

ESTIMATION OF AIRBORNE 106RU ACTIVITY CONCENTRATION FROM TOTAL BETA ACTIVITY OF PM10 PARTICLE FRACTIONS.

Airborne radioruthenium, as a result of an accidental release, presents a risk for occupational and public exposure. In fall 2017, a detection of 106Ru was reported by the European atmospheric radioactive contamination monitoring networks. We investigated the daily specific total beta activity of PM10 particle fractions samples. The presented method enables indirect determination of airborne 106Ru activity concentration from total beta activity, in case 106Ru was confirmed as single excess radiological pollutant. This allows for daily measurements and time-resolved 106Ru activity concentration data. We estimated the indicative committed effective dose due to 106Ru inhalation for the Croatian population during the exposure period. Although the estimated dose value of ~169.7nSv, for ~6-d duration of ruthenium air pollution, was very low, it was ~40 times higher than the value for Hinh from inhalation of other radionuclides (90Sr+137Cs+40K+7Be).

GASTROINTESTINAL PATHOLOGY AMONG RESIDENTS OF THE AREAS AFFECTED BY CHERNOBYL NUCLEAL ACCIDENT

Objective: to assess clinical and morphological characteristics and occurrence of micronuclei of mucocytes of the integumentary and epithelium of the gastric mucosa in residents of areas affected by Chernobyl nuclear accident taking into account Helicobacter pylori (Hp) infection and nutritional factors. Methods: a retrospective study was conducted using a micronuclear test in integumentary-pit epithelium to study cytogenetic effects of small doses of ionizing radiation. Results. Mucocytes with micronuclei were predominantly observed in persons permanently residing in radiation contaminated areas since 1986. The occurrence of micronucleation was not statistically associated with Hp infection. No associations were found for the total alpha and beta activity of biopsy specimens of the gastric mucosa and the density of contamination of the territory at 90Sr and 137Cs. Conclusions: Our findings suggest that gastrointestinal pathology in residents of the territories affected by Chernobyl accident seems to have multifactorial origin related not only to the nuclear accident in Chernobyl.

SULFUR, METAL(LOID)S, RADIOACTIVITY, AND CYTOTOXICITY IN ABANDONED KARSTIC RAŠA COAL-MINE DISCHARGES (THE NORTH ADRIATIC SEA)

Rasa coal, mined on the Istrian Peninsula (NW Croatia) for nearly 400 years up to 1999, is notable for having superhigh organic sulfur, and high levels of selenium, uranium, vanadium, and molybdenum. Selenium is the poison responsible for the widespread loss of cattle and sheep. It is essential to human health in trace amounts, but higher concentrations can be harmful. An estimated 4.4Mt. of coal remains underground within marine carbonate rocks. The study area belongs to the coastal karst of the Adriatic Sea. Several abandoned coal-mine discharges (CMDs) were released into local streams and the Rasa Bay for decades. Therefore, the water quality of a natural karst spring (Fonte Gaja), the Rasa Bay seawater, municipal wastewater, and the Rasa CMDs were investigated, focusing on sulfur, selected metal(loid)s (major, minor, and trace), radioactivity, and cytotoxicity. The Fonte Gaja spring water, unrelated to the Rasa CMD, served as a reference. Its values of Se, U, V, and Mo (µg/L) were as follows: 1.09, 0.75, 1.37, and 2.04, respectively. However, the respective levels (µg/L) were increased in the rest of the water samples as follows: 10.9, 10.8, 4.60, and 33.1. Water sulfate levels were low though. Total beta activities of the CMDs and Rasa Bay water were 235 and 1320 Bq/m3, respectively, below the guideline level of 2000 Bq/m3. The cytotoxicity of water samples on the RTG-2 fish cells was not statistically significant. The large volumes of water involved mean the transport of rather large amounts of Se and U, and their deposition in the Adriatic Sea. Due to the complexity of the karst hydrogeology, knowledge of Se and U circulation patterns is highly needed.

Nuclear contamination sources in surface air of Finnish Lapland in 1965\u20132011 studied by means of 137Cs, 90Sr, and total beta activity

Radionuclides 137Cs and 90Sr and total beta activity were determined from air filters collected in Rovaniemi (Finnish Lapland) in 1965–2011. Nuclear contamination sources present in the air filter samples as well as temporal changes in radionuclide concentrations were examined. Ozone observations and meteorological modeling were used in combination with radionuclide analyses to study the reasons behind the observed seasonal concentration variation. In general, the magnitude and variation in activity concentrations of 137Cs and 90Sr and total beta activity in the surface air of Rovaniemi in 1965–2011 corresponded well with values from other countries. However, the obtained results prove in practice that hardly any refractory or intermediate radionuclides from the destroyed Chernobyl reactor fuel were introduced to Finnish Lapland. The main source of 137Cs and 90Sr and total beta activity in the surface air of Rovaniemi in 1965–2011 has been intense atmospheric nuclear weapon testing in 1950s–1960s and later tests performed in 1965–1980, as well as leakages from underground nuclear tests in Semipalatinsk, 1966, and Novaya Zemlya, 1987. For 137Cs and total beta activity, the influence of Chernobyl and Fukushima accidents was detected.

Natural radioactivity in urban soils of mining centers in Armenia: Dose rate and risk assessment

Soil radioactivity levels, dose rate and radiological health risk were assessed in metal mining centers of Armenia, at the towns of Kapan and Kajaran. Archive soil samples of the multipurpose soil surveys implemented in Kapan and Kajaran were used for estimation of total alpha and total beta activity levels using gas-less iMatic™ alpha/beta cօunting system (Canberra). Ten representative soil samples per town were randomly selected from different urban zones for naturally occurring radionuclide measurements (238U, 232Th, 40 K) using high purity germanium detector. Four radiological indices: radium equivalent activity, outdoor absorbed dose rate, annual effective dose equivalent and excess lifetime cancer risk were estimated based on naturally occurring radionuclide activity concentrations in soils. Results suggest that in Kapan the soil radioactivity, although enhanced by copper and gold-polymetallic mining, are not a significant risk factor to human health. In Kajaran, the soil radioactivity levels were above the background and world average values provided by UNSCEAR, but radionuclides originated in a natural geogenic source and not from mining activities. Generally, in this region no significant radiological risks were identified in relationship with molybdenum, copper, and gold-polymetallic ore mining.