Average Annual Effective Dose Research Articles

Background 210Po activity concentrations in Greenland marine biota and dose assessment

Polonium-210 (210Po) is a radionuclide sentinel as it bioaccumulates in marine organisms, thereby being the main contributor to committed dietary doses in seafood consumers. Although seafood and marine mammals are an important part of the traditional Inuit diet, there is a general lack of information on the 210Po concentrations in the Greenlandic marine food chain leading to the human consumer. Here, we determine background 210Po concentrations in edible parts of different marine organisms from Greenland and provide a dose assessment. Blue mussels (Mytilus edulis), organs of ringed seal (Pusa hispida) and polar bear (Ursus maritimus) displayed significantly elevated 210Po concentrations in respect to all other studied organisms (p < 0.001). 210Po concentrations ranged from 0.02 Bq kg-1, w.w. in Greenland halibut (Reinhardtius hippoglossoides) muscle to 78 Bq kg-1, w.w. and 202 Bq kg-1, w.w. in ringed seal muscle and kidneys, respectively. 210Po concentration ratio for edible parts increases in the order bladderwrack (Fucus Vesiculosus), northern shrimp (Pandalus borealis), blue mussels, and from fish species to ringed seal and polar bear. 210Po distribution in fish, ringed seal, and polar bear follows a general pattern, the lowest concentrations were in muscle, and the highest concentrations were in the organs involved in metabolism. The derived 210Po annual absorbed dose in edible parts of studied marine organisms are several orders of magnitude lower than the recommended dose rate screening value of 10 μGy h-1. Effective doses from intake of 210Po to Greenland average children (1.4 mSv y-1), and high seafood and marine mammal consumers (2 mSv y-1 for adults and 3.6 mSv y-1 for children) are higher than the world average annual effective dose due to ingestion of naturally occurring radionuclides.

OCCUPATIONAL EXPOSURE IN RADIATION APPLICATIONS IN INDIA: TRENDS AND DISTRIBUTION ANALYSIS.

Occupational exposure data in radiation applications provide a good insight on the radiation risks to workers from occupational hazards, the safe practices adopted and in deriving methods to prevent possible radiation exposures. The analysis of occupational exposure may be used to provide regulatory guidance and more focused attention to improve the safety systems, thus improving the personnel and environment safety. In this study, occupational exposure from radiation applications during 2004-18 amounting to a total number of 1951486 occupational dose data are collected and analysed using the statistical software package, SPSS. As recommended by the United Nations Scientific Committee on the Effects of Atomic Radiation, four critical parameters viz., annual collective effective dose, average annual effective dose, individual dose distribution ratio and the annual collective dose distribution ratio for each practice are estimated. Using the trend observed for these parameters, it is predicted that occupational exposure in diagnostic radiology in the year 2023 would increase by 80% in total number of monitored with 76% increase in average collective dose and no significant change in average annual effective dose. In the same manner, nuclear medicine would see 28% of increase in radiation workers with the increase of 24% in collective dose with no significant change in average annual effective dose. Further, the reasons and area of regulatory focus for the different practices are discussed.

Indoor radon measurement in buildings of a university campus in central Iran and estimation of its effective dose and health risk assessment.

Indoor radon is a serious health concern and contributes about 10% of deaths from lung cancer in the USA and Europe. In this study, radon and thoron levels of 20 multi-floor buildings on the campus of Isfahan University of Medical Sciences were measured in cold and hot seasons of a year. SARAD- RTM1688 radon and thoron monitor was used for measurement. The annual effective dose of radon exposure was also estimated for residences on the campus. The results showed that radon concentration was below the WHO guideline (100 Bq m- 3) in most of the buildings. The ranges of radon were from 3 ± 10% to 322 ± 15% Bq m- 3 in winter and from below the detectable level to 145 ± 8% Bq m- 3 in summer. Mostly, the radon concentration in the basement or ground floors was higher than upper floors, however, exceptions were observed in some locations. For thoron, no special trends were observed, and in the majority of buildings, its concentration was below the detectable level. However, in a few locations besides radon, thoron was also measured at a high level during both seasons. The average annual effective dose via radon exposure was estimated to be 0.261 ± 0.339 mSv y- 1. The mean excess lung cancer risk (ELCR) was estimated to be 0.10%. It was concluded that indoor air ventilation, buildings' flooring and construction materials, along with the geological structure of the ground could be the factors influencing the radon concentration inside the buildings. Thus, some applicable radon prevention and mitigation techniques were suggested.

Comprehensive environmental monitoring during remediation of a nuclear legacy site in the Far East of Russia

In compliance with the fundamentals of the government’s policy on nuclear and radiation safety, Russia is continuing to implement its national program for decommissioning its nuclear legacy. Under this program, the State Atomic Energy Corporation, ‘Rosatom’, is carrying out decommissioning and remediation of the Navy’s former shore technical bases (STBs) in the Russian Far East. Along with the ‘old problems’ accumulated during the operation of STBs in the past, new challenges arise because of the planned intensification of radioactive waste (RW) management on the site in the nearest future. The paper presents the results of comprehensive environmental monitoring at the site of temporary storage for spent nuclear fuel (SNF) and RW at Sysoeva Bay, located in Primorsky Krai. One of the site’s features is the cross contamination of the environment with radioactive substances and nonradiological pollutants. The dominant radionuclides in the environmental media are 137Cs, 90Sr, and a minor contribution from 60Сo. The soil contamination with artificial radionuclides predominantly relates to the category of industrial waste with local areas classified as very low-level RWs. The contamination penetrated the underground water via migration from the damaged SNF and RW storage facilities. Along with cesium and strontium radionuclides, widespread groundwater pollution with heavy metals (I–III hazardous classes), including Be and As, was revealed. Moreover, the exceedance of permissible levels of Cd reaches 1000 times, and that of radionuclides (90Sr)reaches 50 times. It dictates the necessity to improve the environmental impact assessment by accounting for the nonradiological pollutants in monitoring design. The radiological conditions in the residential area are characterized by the regional background levels. The average annual effective dose of public exposure due to artificial sources does not exceed 40 µSv.

A 5-YEAR RETROSPECTIVE ANALYSIS OF IONIZING RADIATION DOSE TO HYBRID OPERATING ROOM PERSONNEL IN SAUDI ARABIA.

The annual average effective dose (ED) for operating room personnel (ORP) in Saudi Arabia was estimated from the period of 2015-2019 using thermoluminescent dosemeters. A retrospective analysis was conducted on annual EDs for 7530 ORP working across 52 hospitals. These workers were only exposed to radiation in the operating room. The annual average ED over the period of 5years was found to be 0.59mSv with no incidence of a dose above the annual dose limit of 20mSv. The maximum annual ED reported was 15mSv for an operating room worker in 2019. More than 88% of the workers received an annual ED of <1mSv. The study concluded that the work environment in hybrid operating rooms across Saudi Arabia is safe. However, it is always recommended that workers take every protective measure when dealing with ionization radiation.

Assessment of the radiation safety of drinking water and surface water bodies used for recreational purposes in the Voronezh region

AIM: This study aimed to assess the radiation safety of surface water bodies used for recreational purposes and drinking water used by the population of the Voronezh Region (VR).&#x0D; MATERIALS AND METHODS: The fond materials of the Rospotrebnadzor Administration in VR in 20152019 were used. The following parameters were analyzed: total and activities and specific activity of radioactive substances in the water of open reservoirs (137Сs, 210Po, 226Ra, and 228Ra) and in the sources of drinking water (210Po and 222Rn). The annual effective dose was calculated on the basis of the probable consumption of drinking water from the centralized drinking water supply systems. The content of radionuclides in the water of open reservoirs was analyzed in three control points and in drinking water found in 2,036 water intake artesian wells of the centralized drinking water supply systems. Then, 100% of the sources were surveyed in terms of total and activities. The radiation safety of bottled drinking water from nine manufacturers was assessed on the basis of the data of the Federal State Sanitary and Epidemiological Surveillance. Water in open reservoirs and drinking water, including water packaged in containers, were laboratory controlled on the basis of an accredited testing laboratory center (Center for Hygiene and Epidemiology in the VR) by using MKS-01A Multirad spectrometric installation (Akvilon, Russia). UMF-2000 - and -radiometers were utilized to measure small activities (NPP, Doza, Russia).&#x0D; RESULTS: According to the regional databases of Rospotrebnadzor Administration regarding water from open water bodies for the population (three monitoring points: Tikhaya Sosna, Sukhaya Khvorostan, and Usman rivers) in 20152019, values did not exceed the intervention limit that was registered in terms of the content of the controlled radioactive substances (210Ро, 234U, 222Rn, and 137Сs) and the total and activities. Water from artesian wells used for drinking and domestic purposes fully met the requirements of radiation safety. The average annual effective radiation doses (AAERD) of the population in the VO in 74 settlements within the zones of radioactive contamination due to the Chernobyl disaster ranged from 0.05 mSv/year to 0.12 mSv/year, which was significantly lower than the threshold value (1 mSv/year). The analyzed drinking water samples, water packaged in containers, and the samples produced in the region were in compliance with sanitary and epidemiological requirements, including those for 90Sr and 137Cs radionuclide contents.&#x0D; CONCLUSION: Radiation monitoring in the VR revealed that the content of technogenic radionuclides (137Cs and 90Sr) and other standardized parameters of radiation safety in water of open reservoirs and drinking water did not exceed the threshold values.

Measurement of natural radioactivity and its health hazards associated with the use of different branded cement samples collected from different manufactures in Dhaka city using gamma spectrometry

The radioactivity of naturally occurring radionuclides 226Ra, 232Th, and 40K was determined in thirteen cement samples collected from different manufactures of Dhaka city. The measurement was performed by gammaray spectrometry system using high purity germanium (HPGe) detector. The average activity of 226Ra, 232Th, and 40K in cement samples are fon und to be 30.23±15.04 Bqkg-1, 20.10±11.76 Bqkg-1 and 145.27±24.14 Bqkg-1, respectively. The average values of radium equivalent activity (Raeq), absorbed dose rates (D), internal hazard and external hazard index (Hex), and annual effective dose equivalent are 370 Bqkg-1, 0.27, 0.18, and 27.99 nGyh-1, respectively. The average annual effective dose is found 0.13 mSvy-1, which is less than the recommended value (1 mSvy-1) by the International Commission on Radiological Protection (ICRP-60, 1990), as the maximum permissible annual effective dose to the members of the public. The present study results are discussed and compared with those reported in similar studies and with internationally recommended values. No artificial radioactivity was found in the present study. The results show that the analyzed cement samples do not pose any significant radiation hazard from naturally occurring radionuclides 226Ra, 232Th and 40K reported here and also considered safe for use in buildings construction.&#x0D; J. Bangladesh Acad. Sci. 45(1); 95-104: June 2021

Detection of Activity Concentration, Dose Rate, Absorbed Dose and Effective Annual Dose of Radionuclide's Around Fertilizer and Pesticide Stores, Al-Jazeera Project in Sudan

This paper demonstrates the evaluation of radiological risk factors due to terrestrial radionuclides in soil, about the stores of pesticides and fertilizers for Al-Jazeera agricultural project in Al-Hasahisa, Sudan, to address the issue of the natural radioactivity of this area. Hence, levels of 226Ra, 232Th, 228Ra, 40K and 137Ci in the soil were calculated (by using germanium detector), and then the radiation risk parameters were calculated. its including radioactivity concentration Bq/kg, absorbed dose D, and effective annual dose E, its due to inhalation of radon (222Rn) and consumption of potassium (40K), radium (226Ra), radium (228Ra), thorium (232Th) and mean activity concentrations±deviation The norms for the five primitive radionuclides were, respectively, 268.98±5.22, 14.54±0.2, 15.31±1.54, 20.45±0.96, and 0.34±0.19 Bq kg-1. This results somewhat normal distribution of the United Nations Scientific Committee on the Effects of Atomic Radiation. The results obtained indicate that some radiation risk factors appear to be unfavorable. The mean average absorbed dose±standard deviation (30.54±2.71) nGyh-1 was a slightly normal distribution of the average value of 30.54 nGy/ h, and the Average annual effective dose E (µSVyear-1)±standard deviation (37.48±3.32).) SVyear-1 was a slightly normalized distribution of the value of SVyear-1 its compared with the data of the United Nations Scientific Committee on the Effects of Atomic Radiation. The study focuses light on the demand to develop a comprehensive program for radiation protection in Sudan and in agricultural projects that constantly use pesticides and fertilizers for regulatory oversight.

Comparative evaluation of average doses of radiation of population of Irkutsk and Voronezh regions according to «Unified state system of control of individual doses»

The aim of the study was a comparative assessment of radiation doses to the population of the Voronezh and Irkutsk regions according to the unified state system for monitoring individual doses and radiation-hygienic certification. The objects of research were the territories of the Voronezh and Irkutsk regions, significantly differing in climatic conditions and resources, industrial potential, but comparable in terms of population. The subject of the study was the average territorial values of radiation doses to personnel due to the normal operation of anthropogenic sources, radiation doses to the population due to natural sources and anthropogenic background, radiation doses to patients due to the use of ionizing radiation in medical diagnostics. The method of comparative analysis of effective collective and individual average annual radiation doses was used. In the Voronezh and Irkutsk regions, the priority dose-generating factor is natural radiation, which contribution to the annual effective collective dose is 83.33 and 89.18%, respectively. At the same time, the average individual annual effective doses to the population due to natural sources of ionizing radiation in the Irkutsk region in relation to the Voronezh region are significantly higher for radon – 2,81 times, due to the content of radionuclides in drinking water – 1,93 times and external terrigenous radiation – 1,46 times, which leads to a two-fold difference in the total individual effective doses associated with natural sources of ionizing radiation. These differences are explained by the features of the physical and geographical location of territories. There are significant differences in the values of the average effective annual doses of the population due to global fallouts and past radiation accidents, because a part of the territory of the Voronezh region was exposed to radioactive contamination as a result of the accident at the Chernobyl nuclear power plant (in the Voronezh region – 0.062 mSv / year, in the Irkutsk -0.005 mSv / year). Radiography (63.15 and 67.27%) makes the leading contribution to the value of medical radiation doses, which occupy the second place in the structures of the effective collective annual doses to the population (in the Voronezh region make up 16.46%, in the Irkutsk region – 10.74%) and fluorography (31.29 and 27.41% in the regions, respectively). It was established that the radiation situation in the Voronezh and Irkutsk regions remains stable and safe.

Estimation of indoor radiological hazard on worker and public health in atomic energy centre Dhaka campus, Bangladesh

Introduction: Radiation gives tremendous benefit to mankind but unnecessary radiation may pose harm to worker and public. The purpose of the study is to continuous indoor radiation monitoring of Atomic Energy Centre Dhaka (AECD) campus to minimize the radiological risk on worker and public health in and around the campus. Materials and methods: Continuous indoor radiation monitoring was conducted in the AECD campus from November 2018-April 2019 using the Thermoluminescent dosimeters. The excess life-time cancer risk on worker and public health were estimated based on the continuous indoor radiation monitoring data. Results: The annual effective doses to the worker and public from indoor radiation were ranged from 0.28±0.11 mSv to 0.67±0.25 mSv and the mean was found to be 0.43±0.10 mSv. The excess life-time cancer risk (ELCR) on the radiation worker &amp; public health were estimated based on the annual effective dose and ranged from 1.13 Χ 10-3 to 2.65 Χ 10-3 with an average of 1.72 Χ 10-3.The average annual effective dose and ELCR on worker and public health were lower than those of the worldwide average values. Conclusion: The radiological hazard on worker and public health in and around the AECD campus is not significant because those values are lower than the recommended values of the international commission on radiological protection. Monitoring of these indoor places would help in keeping a record of safe working practices during the handling of the radioactive substances and radiation generating equipments in a radiological facility.

Lifetime Risk of Radiation Induced Severe Hereditary Stochastic (SHS) Effects in Medical Radiation Personnel

Background: Hereditary risk assessments in medical radiation workers must be accentuated as a precaution against genetic diseases. Ionizing radiations can induce hereditary or genetic radiation effects. Aim: To evaluate the lifetime risk of severe hereditary stochastic (SHS) effects in INMOL’s medical radiation personnel. Methods: The determination of the ‘whole-body’ effective doses was performed by ‘dose assessment algorithm’. We adopted the procedure described by ICRP for the assessment of lifetime severe hereditary annual risks by using ‘nominal probability coefficient’. Results: The AAEDs were between 1.41-1.79 mSv (in NM), 1.07-1.43 mSv (in RT) and 1.21-1.70 mSv (in RD) during 2014-2018. A declining trend is observed in AAED values in five consecutive years, due to improvements in radiation protection and safety measures. The risks of severe hereditary effects were also decreased from 2014-2018. The SHS risk was decreased from 5.012×10-4 to 3.948 ×10-4 in NM, 4.004×10-4 to 2.996×10-4 in RT and 4.76×10-4 to 3.388×10-4 in DR department. Conclusion: This study is emphasizing towards evaluating risks of hereditary effects from chronic exposure of radiations in occupational workers to avoid further late genetic complications. Such quantitative indicators would be useful in comparing other lifetime death risks from other harmful substances. Keywords: Hereditary Stochastic Effects; Annual Average Effective Doses; Nominal Probability Coefficient; Medical Radiation; Occupational Radiation Risk Assessments

Analysis on monitoring results of individual dose of occupational external radiation among radiation workers in Lanzhou in 2019

Objective: To analyze the individual dose level of occupational external radiation of radiation workers in Lanzhou in 2019, so as to provide reference for radiation protection and occupational health management. Methods: In April 2020, a total of 1460 radiation workers in Gansu Provincial Center for Disease Control and Prevention in 2019 were selected as the research objects. The unit nature, hospital level and occupational category of the monitored workers were collected, and the monitoring results of external radiation personal dose in 2019 were analyzed and compared. Results: In the occupational external radiation monitoring of radiation workers in Lanzhou in 2019, the effective dose of 48 persons was 1.0~<5.0 mSv, the effective dose of 2 persons was 5.0~<10.0 mSv, the annual collective effective dose was 308.21 people·mSv, and the average annual effective dose of monitored persons was 0.21 mSv/a. There was significant difference in the distribution of annual effective dose per capita among different occupational groups (H=34.43, P<0.05) . The annual effective dose per capita of nuclear medicine personnel was higher (0.56 mSv/a) , followed by interventional radiology (0.33 mSv/a) . The ratio of annual collective dose to total annual collective dose with annual individual dose more than 5 mSv (SR(5)) and the ratio of the number of staff with annual individual dose more than 1mSv to the total number of monitored personnel (NR(1)) were higher in nuclear medicine and interventional radiology personnel. The average annual effective dose distribution of diagnostic radiologists in different level hospitals was statistically significant (H=16.46, P<0.05) . The average annual effective dose in private hospitals, community hospitals and health centers was higher (0.32 mSv) , followed by county hospitals (0.23 mSv) . Conclusion: The individual dose of occupational external radiation of radiation workers in Lanzhou is generally low, and the annual effective dose of nuclear medicine and interventional radiology workers is high. The management of radiation protection should be emphasis on this people. And it is suggested to strengthen the supervision of private hospitals and update and maintain the equipment of community health centers.

Exposed Gamma Doses in air and Assessment of Cancer Risk around Gebze (Kocaeli/Turkey) Region

By this study, it is focused to assessment of inhalation quality for Kocaeli province especially Northeast side of Marmara Sea (Gebze county and its territory). In this case, radioactivity analysis in air was realized via air dose rate measurements around this region which is so closed neighbor to big city Istanbul. By measuring of the outdoor gamma dose rates on 35 stations, it was possible to get the average dose rate. Then it was calculated to annual dose in air. Besides, cancer risk was determined for Kocaeli. All these values were compared with the World’s references (UNSCEAR) and reported finally. It was measured the average dose rate as 23.90 nGyhr-1 and annual dose was calculated to 29.31 μSv. This dose is required to excess lifetime cancer risk as 1.02x10−4. These values could be compared to the similar studies which existed around the world. Finally, the average annual effective dose equivalent and excess lifetime cancer risk for Kocaeli, are less than the world average. This study would be used to a reference for further investigations, besides it will be usefull to compare with different studies for Kocaeli which, will be evaluated in the future, for example after a nuclear pollution, such as based on a reactor leakage comes from Black Sea region and neighbours, nuclear attacks, etc., too. Another benefit would be made to enlarge to find this kind of studies in literature.

Annual effective dose from 222Rn in groundwater of a Nigeria University campus area

Radon, the heaviest among the noble gases in the periodic table of element is a radioactive nuclide that is naturally available in rocks, soil and water. It has become the subject of many research efforts in recent years due to its leading role in causing cancer. In this study, a total of 68 groundwater samples were collected and assayed using alpha spectrometry with RAD7 radon detector with RAD-H2O accessories manufactured by Durridge CO (USA). The 222Rn concentration measured were in the range of 0.6–36.2 Bq L−1 with an average of 13.33 Bq L−1, 7.0–41.5 Bq L−1 with mean value 23.3 Bq L−1 and 0.6–27.4 Bq L−1 with an average value of 7.4 Bq L−1 for hand dug wells (HDW), hand pumped boreholes (HPB) and motorized boreholes (MBH), respectively. About 54, 86 and 15% of samples from the HDW, HPB and MBH, respectively, exceeded the parametric reference level of 11.1 Bq L−1 suggested by United State of America Environmental Protection Agency but lower than the permissible limit of 100 Bq L−1 by World Health Organization (WHO) and European Union. The average annual effective doses resulting from inhalation and ingestion of radon in water obtained for the three groundwater sources are less than recommended limits by WHO and ICRP. The data obtained from this study are comparable with similar studies conducted in Nigeria and other parts of the world as reported in literature. Continuous radon monitoring in drinking water and indoor environment is however recommended for the study area.

Occupational Radiation Exposure and Changes in Thyroid Hormones in a Cohort of Chinese Medical Radiation Workers

ObjectiveThis study aimed to evaluate the association between occupational radiation exposure and changes in thyroid hormone levels among medical radiation workers. MethodsThis retrospective cohort study included 2,946 radiation workers from 20 Guangzhou hospitals. Data on general characteristics, participant radiation dosimetry, and thyroid function test results [thyroid-stimulating hormone (TSH), triiodothyronine (T3), and thyroid hormone (T4)] were extracted from dosimetry and medical records. The generalized estimating equation was used to evaluate the trend of changes in thyroid hormone levels over time and was adjusted for age, gender, and occupation. ResultsThe average annual effective dose was very low and showed a general downward trend. During the follow-up period, changes in T3 and T4 levels among radiation workers were –0.015 [95% confidence interval (CI) −0.018 to −0.012] nmol/L per year and −2.294 (95% CI −2.426 to −2.162) nmol/L per year, respectively. Thyroid hormone levels were significantly different between males and females. T3 levels in the group of upper quartile of dose were significantly higher than in the lower quartile group (P = 0.006). No significant decreased trend in thyroid hormone levels was observed with increasing average effective doses. ConclusionThyroid hormone secretion might be affected even in low-dose radiation exposure environments.

Radiation monitoring of drinking water in the vicinity of the Beloyarsk NPP

The article provides a radiation-hygienic assessment of the current state of drinking water supply sources for the population in the observation area of the the Beloyarsk NPP and the Institute of Nuclear Materials. We determined the content of natural (234U,238U,226Ra,228Ra,210Po,222Rn,210Pb,228Th,230Th,232Th) and technogenic (3H,14C,60Co,90Sr,134Cs,137Cs,238Pu,239,240Pu,241Am) radionuclides in drinking water of tap water, water boreholes and water wells in test settlements located at different distances and directions from radiation hazardous facilities. Results of monitoring of water sources in 2012–2013 and 2019 showed the radiation safety of drinking water in the vicinity of the Beloyarsk NPP according to several criteria. Thus, the maximum levels of the gross specific alpha-activity of radionuclides in water samples were 3.9 times lower than the control level (0.2 Bq/kg), the gross specific beta-activity was 5.7 times lower than the control level (1 Bq/ kg). Over the entire observation period, none of the drinking water samples exceeded the control levels both for individual radionuclides and for the sum of the ratios of specific activities to control levels. The content of natural and artificial radionuclides in drinking water near the Beloyarsk NPP decreases in the following order: water wells &gt; water boreholes &gt; tap water. For the past 20 years, there was a decrease in tritium specific activity in drinking water of the Beloyarsk NPP region by 20–35%, depending on the source of water supply. It was noted that the launch of the BN-800 reactor also did not lead to an increase in the content of other artificial radionuclides (90Sr,137Cs) in groundwater. The average annual effective dose of internal exposure of the population due to drinking water consumption in the vicinity of the Beloyarsk NPP is 0.05 mSv, according to conservative estimates – 0.07 mSv, which is below the radiation safety threshold (0.1 mSv/a) recommended by the WHO. Natural radionuclides play the primary role in the formation of the annual average effective dose for internal irradiation (98.9%) due to drinking water consumption on the considered territories.210Po makes the largest contribution to the dose from natural radioisotopes – 43%, somewhat less is made by210Pb – 25%. The third place in the dose formation from natural radionuclides belongs to234U (8%),228Ra (7%),226Ra (6%) and230Th (6%). The contribution of other natural radioisotopes in the formation of the internal radiation dose from drinking water consumption does not exceed 2-3%. The contribution of technogenic radionuclides to the annual average effective dose from the consumption of drinking water is negligible (about 1%). Of the technogenic components,90Sr (60%),3H (20%), and241Am (12%) play the most significant role in the formation of the internal exposure dose.

Radon survey in kindergartens and schools of Dushanbe, Republic of Tajikistan

The paper presents results of the radon survey carried out in preschool and school institutions in Dushanbe, Republic of Tajikistan. Radon concentration was measured using solid state nuclear track detectors Radtrak2. Track detectors were exposed for 3 months during the heating and warm seasons of the year in the same premises. In total, the measurements were performed in 200 premises of 14 kindergartens and 36 schools. The radon equilibrium equivalent concentration during the heating and warm seasons and the annual average radon equilibrium equivalent concentration were calculated. Annual average radon equilibrium equivalent concentration in surveyed buildings ranged from 42 to 331 Bq/m3 with the mean value of 98 Bq/m3 on the first floor and 56 Bq/m3 on the second floor. It was shown that both seasonal values and annual average value of radon equilibrium equivalent concentration in the premises on the second floor are lower than in the premises on the first floor. The annual average effective dose to children from exposure to radon and its progeny in the premises of schools and kindergartens in Dushanbe ranged from 0,64 to 1,64 mSv. The limit value of annual average radon equilibrium equivalent concentration in dwellings and public buildings is set to 100 Bq/m3 for newly built buildings and 200 Bq/m3 for existing buildings in the Radiation safety norms (NRB-06) of the Republic of Tajikistan. This limit was exceeded only on the first floors in one kindergarten during the heating season, in three schools during the warm season and in eight schools during the heating season. When comparing the results of measurements of radon equilibrium equivalent concentration with data on the geological structure of underlying rocks at the locations of the surveyed buildings, no regularity was found. Additional detailed measurements in the buildings, including basements, will help to identify the source of radon entry into the indoor air and to develop recommendations for implementing radon remediation actions separately for each building. The survey results were also used to develop a radon map of Dushanbe.

Radon study around earthquake affected areas of Nepal

Indoor radon concentrations were measured in dwellings of the earthquake-affected areas of Kathmandu valley, Gorkha, and Sindhupalchowk districts of Nepal using passive radon dosimeter LR115, a Solid State Nuclear Track Detector, SSNTD. The radon concentrations in dwellings of Kathmandu valley ranged from 11±6 Bq/m3 to 135±26 Bq/m3 with a mean of 67.63 Bq/m3. For Gorkha, it ranged from 18±7 Bq/m3 to 363±65 Bq/m3 with an average of 104.64 Bq/m3 while minimum, maximum and average radon concentrations for Sindhupalchowk were 14±6 Bq/m3, 397±71 Bq/m3, and 78.46 Bq/m3 respectively. The average annual effective dose to the inhabitants of Kathmandu valley, Gorkha, and Sindhupalchowk districts was calculated as 1.46 mSv/y, 2.26 mSv/y, and 1.69 mSv/y respectively. These annual doses were well below the action level of 10 mSv/y recommended by the International Commission on Radiological Protection which implies no significant radiological health hazards. Also, Excess Lifetime Cancer Risk and Lungs Cancer Cases per year per million people were determined.&#x0D; BIBECHANA 18 (2) (2021) 61-67

Gamma dose monitoring to assess the excess lifetime cancer risk in western Himalaya

The present work focussed on demarcation of areas with cancer development risk through excess lifetime cancer risk (ELCR) by assessing spatial variability of gamma dose in outdoor and indoor environment in western Himalaya. Average outdoor gamma dose and outdoor annual effective dose exceed the corresponding world averages. An indoor gamma dose (barring Budgam, Ganderbal and Kashmir University of Kashmir division and Reasi city of Jammu division) also exceed the world average. The probability of cancer development is higher in main-Shopian (3.65 × 10−3), Mala Bagh (2.80 × 10−3), Bundoda (2.88 × 10−3) and Dhadpeta (2.89 × 10−3), as total ELCR exceeds the world average.

Calculation of natural external radiation dose rate for environmental impact assessment, case study: Abu Zenima area, Southwestern Sinai, Egypt

ABSTRACT The present article aims to assess environmental impact coming from terrestrial natural radionuclides, external gamma exposure dose radiation and the average effective annual dose value. The obtained data can be used to provide technical support for the social communication of nuclear energy bodies to understand the natural radiation background of the study area. To achieve the aim, 11271 measurements of 238U, 232Th and 40K were carried out using airborne gamma ray spectrometry for the study area. These measurements were used and converted in to specific activity for calculating the absorbed dose rate (D) and the annual effective dose (E) to infer the average annual effective dose value for the population of Abu Zenima area. The calculated specific activity of U238, Th232 and K40, absorbed dose rate, annual effective dose rate, collective dose and annual effective dose value for the population were mapped through Geographic Information System (GIS) using Arc map software version 10.5. The specific activity concentration of U238 ranged from 1 to 400 Bq/kg, Th232 ranged from 1 to 650 Bq/kg and K40 ranges from 1 to 4000 Bq/kg. The absorbed dose rate values ranged from 3.25nGy/h to 261 nGy/h. Annual effective dose rate values, varying from 21 to 9867 µSv y−1 with an average value of 172µSv y−1which is higher than the worldwide average value of 70µSv y−1 (for outdoor exposures from terrestrial radiation sources).The collective effective average dose (S), varied from 1.16 to 424.31 with an average value of 20.77 man mSv. Finally, average total population effective dose of Abu Zenima area ranged from 0.0013 to 0.0375 with an average value of 0.0129mSv. From all these results, it was concluded that Al Sahu, Al Nasb, Serabit El Khadim and Al Lehianlocalities have high background radiation.