Natural Radiation Sources Research Articles

Обеспечение радиационной безопасности при обращении с РАО: дозы облучения и перспективы развития регулирующих основ

Based on the evaluation of data on public exposure from various sources, the paper demonstrates that the contribution of nuclear power and nuclear industry into individual and total collective doses in Russia is minor compared to the exposure from natural radiation sources and medical treatment even in regions with sites run by Rosatom. The personnel are exposed to a level being considered common for the nuclear industry. Public exposure associated with the management of RW is practically absent with the same exposure levels being forecasted in the long run. Based on the above and considering the objectives for the USS RW development, the paper presents relevant proposals on further elaboration of basic radiation safety regulations: NRB, OSPORB and SPORO.

Passive radium measurements in soil samples from North Western desert of Egypt using LR-115 nuclear track detector

Background: The knowledge of the distribution of radionuclides and radiation levels in the environment is important for assessing the effects of radiation exposure to human beings. Radium (226Ra) and its ultimate precursor uranium (238U) are the parent sources of radon (222Rn).222Rn is the main natural radiation source of exposure of human beings and has been recognized as a carcinogenic gas. Measurement of radon and radium in soil samples is useful in studying the health risks. Objectives: The purpose of this study was to investigate the radium content in soil samples from northwestern desert of Egypt. Materials and Methods: A total of 40 soil samples were collected from four regions named El-Alamin, El-Dabaa, Marsa Matrouh, and El-Negala cities in northwestern desert of Egypt. The radium contents in soil samples were estimated by sealed cup technique using LR-115 nuclear track detectors. Results: Radium concentration has been found to vary from 11.58 to 29.11 Bq/kg with an average value of 20.63 ± 1.46 Bq/kg. Conclusion: The observed values of radium concentration in all soil samples are less than the permissible value of 370 Bq/kg recommended by the UNSCEAR 2000 and OCED 1979. Hence, the result shows that these areas under study are safe as far as the health hazard effects of radium are concerned.

Thorium content in soil, water and sediment samples and fluvial sediment-associated transport in a catchment system with a semiarid-coastal interface, Brazil.

Thorium (Th) is one of the main sources of natural radiation to ecosystems. However, data regarding Th concentrations in rocks, soil, water and sediments are currently scarce. Accordingly, this study aimed to establish background concentrations and quality reference values (QRVs) for Th in the environmentally impacted Ipojuca River catchment in Brazil, where the weathering of granites releases Th into the environment. Additionally, the study aimed to calculate Th fluxes in water, and both bed and suspended sediment. The mean Th concentration in the study catchment soils was 28.6 mg kg-1. The QRV for Th was estimated to be 21 mg kg-1 and 86.3 Bq kg-1. Bed and suspended sediment-associated concentrations ranged from 2.8 to 32.9 mg kg-1. Suspended sediment-associated discharge (3.42 t year-1) accounted for more than 99% of the total Th flux, while the dissolved phase transport was negligible in comparison. At the downstream cross section in the study catchment, suspended sediment samples exhibited Th concentrations similar to those observed in rivers impacted by mining activities. The discharge of sediment to the ocean from the study area is mainly triggered by soil erosion processes in the hotspot region (middle-inferior course). It is essential to identify Th hotspots before establishing environmental policies regarding human health and environmental protection.

The national radon program: Implementation experience and challenges for the future

The authors share their experience and represent the historical overview of activities on public radiation protection against radon and other natural sources of radiation in Russia. Special attention is paid to the country’s first national radon program - Federal Target Program “Radon” (FTP “Radon”, 1994-1996). Organization, structure, main goals and objectives of the FTP «Radon» are discussed. In particular, it was noted that in a short period of time the country’s regulatory and methodological framework was developed. The scientific basis for identification of the radon prone areas and regulatory support for building construction at the sites was developed. The national SSND equipment was produced and QA/QC system implemented. The national and regional radon surveys have been performed. Unfortunately, the economic situation of those years did not allow to fully implement the planned set of measures at the federal and regional levels. Nevertheless the accumulated experience served as a scientific and technical basis for further improvements in this field and to be consistent with the modern radon regulatory issues and approaches developed by the international organizations (ICRP, IAEA, WHO).

Modelling ventilation system operation in order to reduce natural radiation in buildings

Over 70% of the total annual radiation dose received by the human population comes from natural sources of radiation; 40% of that quantity is due to the presence of the natural radioactive gas, radon. Its most common and most significant isotope is radon-222 (222Rn). Indoor radiation activity occurs due to radon migration from soil and due to other radioactive substances present in building materials. The most important factor that influences indoor radiation activity concentration is ventilation. It is very important to optimise the concentration of indoor radiation activity and ventilation system intensity for human health, environment and energy saving, because earlier studies paid scant attention to the issue of radon concentration decrease by ventilation. The software Resrad-Build is used to simulate exposure to radiation of persons working or living in a building contaminated with radioactive material, in the case of a typical basement and a room above the basement. The model evaluated the maximum length of time between two automatic activations of the ventilation system and the minimum value of the permanent ventilation intensity needed to make the average annual received radiation dose for the person less than 1 mSv.

Incidence of brain and spinal cord cancer and county-level radon levels in New Jersey, Wisconsin, Minnesota, Pennsylvania, and Iowa, USA.

Ionizing radiation at diagnostic and therapeutic doses is a known contributor to the development of brain and spinal cord (CNS) cancer. However, little is known about risk from exposure to radon, a natural radiation source which the general population is exposed to residentially and environmentally. This study investigated correlations between mean county radon levels and CNS cancer incidence in five highly populated and radon-enriched US states (Minnesota, mean radon level 4.6pCi/L; Wisconsin, 5.7pCi/L; Pennsylvania, 8.6pCi/L; Iowa, 6.1pCi/L; and New Jersey, 4.4pCi/L). Mean radon levels per county were accessed through AirChek, which provides publicly available radon data measured in residences and workplaces. CNS cancer incidence data were accessed through the states' health department websites and span differing amounts of time due to the publicly accessible nature of the data, though all time spans were over 10years. Negative binomial regressions were run to assess correlations between mean radon and CNS cancer incidence per county. Quantile maps were constructed and Moran's I was calculated to assess spatial autocorrelation in residuals; no spatial autocorrelation was evident. Iowa was the only state with a significant positive association between radon and CNS incidence; no associations were detected in other states, and a negative association was observed in the 5 states combined. This study does not provide evidence that radon is a risk factor for CNS cancer; however, the possibility of an association cannot be ruled out due to limitations of the study, principally its ecologic nature and lack of individual-level exposure data.

Measure the rate of Radiation Activity in Soil sample from the depth of Sindbad land in Basrah Governorate

Uranium, radionuclide’s, thorium and potassium are relatively abundant in soils. Because of their radiation, these radionuclide’s pose exposure risks that can lead to health problems such as cancer for exposed people. There is therefore growing concern about the health risks associated with exposure to the natural sources of radiation in our environment. The specific activity 238U, 232Th, 40K,226Ra in forty soil samples collected from different locations of Al-sindbad land in the province of Basra – Iraq using Sodium Iodide NaI(TL) detector. The specific activities for the whole study areas were compared the Local, world average and permissible recommended limits. The results showed thatthe specific activity of226Ra,232Th,238U, and 40K, in the samples rang from( 17.14-39.07)Bq/kg, ( 1.8-22.88) Bq/kg, (0.68-2.24) Bq/kg and (278.11-402.29)respectively, Also evaluation of radiological hazard effects for Gamma ray (the radium equivalent rate (Raeq) which calculated from concentration of 232Th,238Uand 40K ranges between (30.72-65.48) Bq/kg with mean value of (43.362)Bq/kg, the absorbed dose Rate (D γ ) for the soil samples in the study area range from (26.54-43.92) nGy/h with an average value of(33.216)nGy/h, the annual effective dose rate (AEDEoo) range (0.13-0.22)mSv/y with an average value of(0.163) mSv/y, The annual effective dose rate (AEDEin) range (0.03-0.05) mSv/y with an average value of(0.04) mSv/y, The internal hazard index (Hin) range (0.2-0.35) with an average value of(0.255)and the external hazard index (Hex) range (0.15-0.25) with an average value of (0.186).The results of the present study have shown that the rates of Specific activity of226Ra,238U, 232Th and 40K, and radiological hazard effects Rate for Gamma-ray in environmental samples were all lower than the value of the global limit(33, 35, 30, 400)Bq/kg respectively according to UNSCEAR. We conclude from this study that the environment of Al-Sindbad land in the province of Basra – Iraq is within a normal background radiation.

Radon. Advanced regulatory approaches to public radiation protection

Currently in the Russian Federation the procedure for revision of the national regulatory documents (Radiation Safety Standards (NRB-99/2009) and Basic Sanitary Rules for Ensuring Radiation Safety (OS-PORB 99/2010) has been initiated. In this regard, the authors consider to discuss with the scientific community the necessity to provide amendments in the current Radiation Safety Standards concerning public radiation protection against natural radiation sources, in particular, radon. The main objective is to provide consistence existing national regulatory requirements with the modern international approaches set out in the ICRP and IAEA documents. In this regard, specific proposals on improvement of the regulatory and legislative framework in this field are presented. This will be the basis for the implementation of national radon mitigation strategy in view of the ICRP, WHO and IAEA recommendations and the requirements of the State policy of the Russian Federation in the field of Nuclear and Radiation Safety.

Study on Radiation Characteristics of Electromagnetic Equipment

Aiming at the increasingly complex battlefield electromagnetic environment, the basic composition of natural radiation source and artificial electromagnetic radiation is analyzed. In order to construct and simulate complex electromagnetic environment, a general electromagnetic equipment radiation source modeling method is proposed, which is various on the battlefield. Electronic countermeasures equipment can be described by five components to describe the characteristics of its frequency domain, energy domain, and signal modulation domain.

Field Intercomparison of Radiometers Used for Satellite Validation in the 400–900 nm Range

An intercomparison of radiance and irradiance ocean color radiometers (the second laboratory comparison exercise—LCE-2) was organized within the frame of the European Space Agency funded project Fiducial Reference Measurements for Satellite Ocean Color (FRM4SOC) May 8–13, 2017 at Tartu Observatory, Estonia. LCE-2 consisted of three sub-tasks: (1) SI-traceable radiometric calibration of all the participating radiance and irradiance radiometers at the Tartu Observatory just before the comparisons; (2) indoor, laboratory intercomparison using stable radiance and irradiance sources in a controlled environment; (3) outdoor, field intercomparison of natural radiation sources over a natural water surface. The aim of the experiment was to provide a link in the chain of traceability from field measurements of water reflectance to the uniform SI-traceable calibration, and after calibration to verify whether different instruments measuring the same object provide results consistent within the expected uncertainty limits. This paper describes the third phase of LCE-2: The results of the field experiment. The calibration of radiometers and laboratory comparison experiment are presented in a related paper of the same journal issue. Compared to the laboratory comparison, the field intercomparison has demonstrated substantially larger variability between freshly calibrated sensors, because the targets and environmental conditions during radiometric calibration were different, both spectrally and spatially. Major differences were found for radiance sensors measuring a sunlit water target at viewing zenith angle of 139° because of the different fields of view. Major differences were found for irradiance sensors because of imperfect cosine response of diffusers. Variability between individual radiometers did depend significantly also on the type of the sensor and on the specific measurement target. Uniform SI traceable radiometric calibration ensuring fairly good consistency for indoor, laboratory measurements is insufficient for outdoor, field measurements, mainly due to the different angular variability of illumination. More stringent specifications and individual testing of radiometers for all relevant systematic effects (temperature, nonlinearity, spectral stray light, etc.) are needed to reduce biases between instruments and better quantify measurement uncertainties.

Laboratory Intercomparison of Radiometers Used for Satellite Validation in the 400–900 nm Range

An intercomparison of radiance and irradiance ocean color radiometers (The Second Laboratory Comparison Exercise—LCE-2) was organized within the frame of the European Space Agency funded project Fiducial Reference Measurements for Satellite Ocean Color (FRM4SOC) May 8–13, 2017 at Tartu Observatory, Estonia. LCE-2 consisted of three sub-tasks: 1) SI-traceable radiometric calibration of all the participating radiance and irradiance radiometers at the Tartu Observatory just before the comparisons; 2) Indoor intercomparison using stable radiance and irradiance sources in controlled environment; and 3) Outdoor intercomparison of natural radiation sources over terrestrial water surface. The aim of the experiment was to provide one link in the chain of traceability from field measurements of water reflectance to the uniform SI-traceable calibration, and after calibration to verify whether different instruments measuring the same object provide results consistent within the expected uncertainty limits. This paper describes the activities and results of the first two phases of LCE-2: the SI-traceable radiometric calibration and indoor intercomparison, the results of outdoor experiment are presented in a related paper of the same journal issue. The indoor experiment of the LCE-2 has proven that uniform calibration just before the use of radiometers is highly effective. Distinct radiometers from different manufacturers operated by different scientists can yield quite close radiance and irradiance results (standard deviation s < 1%) under defined conditions. This holds when measuring stable lamp-based targets under stationary laboratory conditions with all the radiometers uniformly calibrated against the same standards just prior to the experiment. In addition, some unification of measurement and data processing must be settled. Uncertainty of radiance and irradiance measurement under these conditions largely consists of the sensor’s calibration uncertainty and of the spread of results obtained by individual sensors measuring the same object.

A Glance at the Errors of Some Studies on the Health Effects of High Background Natural Radiation Areas

There is no place on the Earth, the planet we live on, where the natural background radiation level is zero. Since the birth and even in our fetal stage, we have been exposed to different sources of natural radiation. Life, in fact, evolved in a radiation environment that was much more harsh than today. Earth serves as a source of terrestrial radiation. Uranium, thorium, and radium are among the radioactive materials that naturally exist in soil and rock. Moreover, the air, we breathe, contains radon, a colorless, odorless, radioactive gas that is created naturally by the radioactive decay of uranium and radium. The crucial importance of the studies on the health effects of living in areas with high levels of background radiation for understanding the biological impact of exposure to low doses of ionizing radiation is well documented. Despite the undeniable need for accurate information about the health effects of exposure to high levels of background radiation, many published papers suffer from methodological and other common types of errors. In this paper, we review three articles published on high background radiation areas. The first paper has addressed the frequencies of unstable (dicentrics& rings), stable (translocations & inversions), and other types of chromosome aberration in adult men from both high background radiation areas of Kerala and areas with normal background radiation. The second paper has addressed different aspects of the world’s high background natural radiation areas. Finally, the third paper has tried to address the role of background radiation on males to females’ ratio at birth. The author has mainly referred to the studies performed on the impact of radiation exposures from nuclear testing (worldwide) and Chernobyl fallout (in Europe).The major shortcomings of these three papers, especially methodological errors, which affected the accuracy of their findings and conclusions are discussed.

Assessment of indoor radon concentration in residential homes and public places in south of Tehran, Iran

Radon as primary source of natural radiation, is the second leading environmental cause of lung cancer after tobacco smoke. Radon gas is important sources of natural radiation. The aim of this study was to measure the concentration of radon gas in residential homes and public places in Kahrizak city and in the buildings near faults. Totally, 37 residential homes (two detectors at each home), and 23 public places (one detector in each place) were studied. The indoor radon concentration in the ground floor of residential homes and public places was measured by a long-term passive method using CR-39 detector. Data were analyzed by SPSS and GIS software. In the residential homes, radon concentration range was 25.1–130.2 ± 19.0 with average of 60.3 Bq/m3 and in public places, radon concentration range was 18.9-95.6 ± 21.9 with average of 55.8 Bq/m3. Majority of residential homes and public places had an effective annual dose of 0.8–1.6 mSv/y. 28.1% and 26.0% of the total measured concentration of residential homes and public places were in acceptable range based on the U.S.EPA, respectively.

Determination of indoor radon levels at campuses of Üsküdar and Okan Universities

Radon is the largest source of natural radiation all people exposed to. It can form in houses due to building materials or enters through cracks in walls, basement floors and with water used in bathroom showers and faucets. The buildings keep radon inside, where it accumulates and may become a health hazard if the building is not properly ventilated. Radon can be inhaled into the lung, and especially short-lived products of its disintegration can cause long-term internal exposure. In this study, indoor radon survey was carried out at several campuses of Uskudar and Okan Universities by using AlphaGUARD active radon detector.

RESULTS OF RADON INSPECTION OF SETTLEMENTS COMPROMISED DUE TO DISPOSAL OF RADIOACTIVE WASTE INTO THE TECHA RIVER

During past decades, specialists perform an epidemiological observation of the population exposed to the impact of radioactive discharges into the Techa River. The Techa River cohort studies have identified excess cases of leukemia and solid cancers associated with radiation exposure. At the same time natural sources of radiation, such as radon and its decay products, known to be significant human radiation exposure factor, are not sufficiently studied on this territory. The purpose of the study is to assess the mean value and the distribution indices of radon concentration in 14 settlements affected by radioactive contamination. Radon inspection in settlements located on the Techa River (Chelyabinsk and Kurgan regions) was executed. The measurements were performed in 511 dwellings. For radon inspection there were applied detectors based on LR-115 Kodak Track. The analysis shows the sample both to be representative and allow to estimate radon exposure for inhabitants. The average radon concentration in dwellings is 150 Bq/m3, which results in an annual effective dose of 11 mSv. The estimated number of dwellings with radon concentrations above ECC radon action level 200 Bq/m3 is 19. The factors affecting indoor radon accumulation were established. The radiation dose due to the inhalation of radon, accumulated over a long period of time, seems to be generally comparable to doses associated with the radioactive discharges into the Techa River during the 1949-1956.

RADIATION SITUATION AT THE SITE OF THE FORMER LERMONTOV ALMAZ PRODUCTION ASSOCIATION

In the article there are presented data of the study of the radiation situation on the territory and at premises of the “Electric Mechanical Plant” Company, one of the units of the former uranium mining and milling facility of the former Lermontov Almaz Production Association. At the area of waste rock dumps and off-balance ores, the radiation situation was shown to meet requirements of health regulations SP LKP-91.The radiation situation in 14 out of 15 observed workshops and office premises meets the requirements for the limitation of the public exposure to natural radiation sources in occupational conditions established by health regulations and norms SanPiN 2.6.1.2800-10. In one building (warehouse premises), the requirements for equivalent equilibrium volumetric activity of radon (EEVA) in indoor air are exceeded. Based on the annual EEVA of radon values the assessment of effective doses in the work of the personnel over the one shift, was shown to be overestimated up to 7 times due to the daily variation of radon volumetric activity concentration.

Ionizing radiation affects miRNA composition in both young and old mice

Purpose: Humans are exposed to both natural (e.g. soil, cosmic rays) and human-made radiation sources (e.g. medical devices, nuclear energy production) on a daily basis. The use of medical radiation sources such as Computed Tomography (CT) scans and X-ray has increased rapidly, especially in the treatment of older populations. Micro Ribonucleic Acids (miRNAs) are the major regulators of multiple low-dose radiation-induced biological processes through post-translational inhibition. As a result, understanding age-related changes of miRNA profiles that may compromise the population after low dose radiation exposure has become increasingly important.Materials and methods: In this study, we irradiated both young (2 months) and old (26 months) C57BL/6J mice with low dose radiation (10 mGy and 100 mGy at 1 mGy/min using an open beam 60Co gamma source) and checked the miRNA expression profiles.Results: The global miRNA expression of old mice was significantly reduced compared to that of young mice. Low dose radiation at 10 mGy significantly increased the global miRNA expression in both old and young mice one week following irradiation, which suggests that 10 mGy low dose radiation may reverse the global inhibition effects of aging on miRNA expression. Higher 100 mGy radiation slightly reduced the global expression of miRNAs. We also identified several miRNAs that were elevated or reduced in all of the radiation treatment groups; these can be further explored as candidates for the radiation-induced bio-markers.Conclusions: The results of our study demonstrate that both radiation and aging can influence the global expression of miRNAs, while low dose radiation modulates the expression of miRNAs in a dose-, time-, and age-dependent manner.

Indoor radon measurement in residential/commercial buildings in Isfahan city

Introduction: People are constantly exposed to radiation from natural and artificial sources of radiation. Radon is one of the natural radiation sources that its concentration in very high in some part of the world. The presence of radon gas in the air can increase the risk of lung cancer. In this study, the level of indoor radon in dwellings of Isfahan city was surveyed. It should be mentioned that an active alpha GUARD instrument was used to measure radon concentration. All of the measurments took place during the winter and spring of 2018. Materials and methods: In the present survey, 51 residential/commercial buildings were considered to radon gas monitoring based on the population distribution on 15 urban areas and the population of each area and technical possibilities. In each residential/commercial buildings, sampling was carried out at different floors of the building. A professional radon monitoring device (Alpha GUARD PQ2000 PRO) was used to measure indoor radon gas con-centration. Results: The Results of measuring were shown that the radon concentration in the residential/commercial buildings varied from 3 to 251 Bq / m3, with a mean value of 28.57 ± 39.38 Bq / m3. The average annual effective dose re-ceived by the residents of the studied area was estimated to be 0.49 mSv. The results showed a significant difference between the average radon concentra-tion in different floors and the different ventilation of the building, higher values in the lower floors and weaker ventilation. Conclusion: Indoor radon concentration in 4 % of the building was deter-mined to be higher than the limit (100 Bq / m3) recommended by the World Health Organization.

Microwave Evaluation of Electromagnetic Compatibility of Dielectric Remedial and Therapeutic Materials with Human Body

Inherent attribute of the materials using in medicine and biology is microwave range electromagnetic radiation (EMR). The methods of the identification and determination of the compatibility of indicated materials are considered in the paper. The man-made and natural sources of the microwave radiation are described. Examples of the microwave signals using in practical medicine technologies are given. The parameters of microwave signals that can be used to identify biomedical materials are determined. The features of the studied positive and negative electromagnetic radiation streams and possibilities for their use for therapy and identification of biomaterials are described. The results of experimental investigation of the EMR of dental materials are presented. Electromagnetic properties of the dental materials and natural teeth tissues were compared. The recommendations for possible use of the biomaterials electromagnetic identification methods are given. The features of the materials for the physiotherapy were studied experimentally. It was stated that physiotherapeutic materials in determined regimen of the therapy, beside the thermal action, form microwaves streams that could be positive or negative. The level of the microwave component and corresponding physiotherapeutic procedure effectiveness may be regulated by the combination of the physiotherapeutic materials.

Public exposure to natural radiation sources (Ramsar Case Study)

Introduction: Human beings are naturally exposed to ionizing radiation in any environment. There are two main contributors to radiation exposures from natural sources: cosmic rays, Cosmo genic radionuclides, and radioactive nuclides that originated in the earth's crust. According to the latest data provided by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the estimated worldwide average annual exposure to natural radiation sources is 2.4 mSv, and the most exposures are in the range of 1–13 mSv/a. There are several small areas throughout the world where people are exposed to natural radiation sources that are in excess of those considered normal background”. However, there are no specific criteria in this regards, these areas are referred to as High Natural Radiation (HNRA) areas. Ramsar is one of these areas. The natural radioactivity of Ramsar is mainly due to the presence of Ra-226 along with its daughters. The aim of this study was to determine the internal and external exposures from natural radiation sources in Ramsar, and to estimate the total annual effective dose for the people in Ramsar. Materials and Methods: In this research, the all radiation sources and exposure pathways of people living in Ramsar were investigated. The concentration of 226Ra was measured by alpha spectrometry and radon emanation in different samples including foods and drinking water, and the internal dose was estimated. In addition, the annual effective dose of exposure to gamma rays and the annual effective dose due to inhalation of radon gas were calculated for residents. Results: The mean annual effective dose due to exposure to indoor gamma rays in Ramsar was 0.66 mSv, the range was 0.3 to 48 mSv, the mean annual effective dose due to exposure to outdoor gamma rays was 0.86 mSv, and the minimum was 0.1 mSv. The mean annual effective dose of internal exposure to radon gas was 10.3 mSv and its range was from 0.9 to 232 mSv. The mean annual effective dose due to ingestion of 226Ra was found 10 µSv and its range was 1 to 81 μSv. Conclusion: Based on the results of this study, the public annual effective dose of Ramsar from exposure to natural radiation sources was 1.25 to 281 mSv, with a mean value of 12 mSv. The results of this study show that the mean value (12 mSv) is approximately 5 times greater than the worldwide mean annual exposure to natural radiation sources reported by the UNSCAER (2.4 mSv). The results obtained could be used in determining the reference levels for controlling the exposure of people and in taking preventive measures to reduce the radiation exposure of the residents. In addition, the results of this research could be useful in the study of the effect of radiation on the public health.