Maximum Annual Effective Dose Research Articles

Evaluation of radioactivity concentration in farm fresh milk and concomitant dose to consumer

In this study, activity concentrations of natural radionuclides in 28 raw milk samples collected from different dairy farms in Dhaka city of Bangladesh were measured using a high-purity germanium (HPGe) detector for the first time. The activity concentration of 226Ra, 232Th, and 40K in the investigated fresh milk samples ranged from BDL (Below detection level) to 26 ± 1.6 Bq/kg, BDL to 11.7 ± 3.3 Bq/kg and 101 ± 17 to 384 ± 32 Bq/kg, respectively. No artificial radionuclides were found in the investigated samples. Present results show inline within the range of available data in the literature. Annual committed effective doses were estimated following the consumption characteristics of raw milk by city population, values are found within the limiting range recommended by international organizations due to consumption of foodstuffs. Additionally, real-time gamma-ray dose rate in the farms/sampling locations was found in the range of 0.12 ± 0.01–0.20 ± 0.01 μSv/h by using a digital gamma survey meter (Gamma Scout) and the calculated maximum annual effective dose due to outdoor absorbed dose was found to be 0.25 mSv/y, which shows lower than the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) recommended limit of 2.4 mSv/y. This study indicates that the concentration of radionuclides in the farm fresh milk of Dhaka city does not pose any unwanted risk to public health, and it is safe to consume by both children and adults with the current intake level.

An Evaluation of Radon in Drinking Water Supplies in Major Cities of the Province of Chimborazo, Central Andes of Ecuador

The activity concentrations of 222Rn were measured in 53 public water supplies of underground (50) and surface (3) origin, and the relation of such with five geological units where these supplies are located, in the central Ecuadorian Andes, was also explored. These units supply drinking water to 10 cities, located between the 1500 and 3120 m.a.s.l. The experimental setup consisted of the RAD7 radon detector and the RAD H2O degassing system. The 222Rn levels measured in groundwater ranged from 0.53 to 14.78 Bq/L while surface waters did not indicate detectable radon levels. The radon concentrations were below the parametric value of 100 Bq/L for water intended for human consumption, recommended by the European Atomic Energy Community (EURATOM) in its Directive 2013/51, and the alternative maximum contamination level (AMCL) of 150 Bq/L, proposed by the Environmental Protection Agency (EPA). The Pisayambo Volcanic unit, mapped as intermediate volcaniclastic to felsic deposits, presented a mean radon concentration higher than the other geological units and lithologies (9.58 ± 3.04 Bq/L). The Cunupogyo well (11.36 ± 0.48 Bq/L) presented a radon concentration more than 70% higher than the neighboring springs, which may be explained by its proximity to the Pallatanga geological fault. The maximum annual effective doses, by cities, due to the ingestion and inhalation of radon, ranged from 0.010 to 0.108 mSv and from 0.008 to 0.091 mSv, respectively; therefore, these waters do not represent a risk to the health of the population. In addition, a correlation was observed between the activity concentration of 222Rn and the activity concentration of the parent 226Ra in samples collected from some springs.

Assessing health risk associated with uranium in Rietspruit water, far West Rand goldfield, South Africa

Uranium, U, as a radiological and chemically toxic element has detrimental impacts on human health when ingested at elevated concentration in water. Effluents from an underground gold mine located in the head water region of the Rietspruit contaminated the stream with waterborne uranium. The Rietspruit is a tributary of the Vaal River and subsequently flows through residential and agricultural land. Water samples from the stream were collected and analysed using inductively coupled plasma mass spectrometry to determine the concentrations of dissolved U. The maximum concentration of U recorded was 781.9 µg/L at the mine from where it decreases with growing distance from the mine. Results from calculations showed that the maximum annual effective dose at the mine was above the regulatory limit for public exposure for all age groups. The radiological risk associated with consumption of untreated water from the Rietspruit is lower than the chemical risk. The chemical risk ranges from 0 to 37.2 while the highest life-time cancer risk was 1.7 E-03 for morbidity cancer risk and 1.1 E-03 for mortality cancer risk. The chemical risk analysis showed that within 24 km of downstream of the mine, stream users are exposed to toxic U levels. Therefore, adequate interventions by relevant government agencies are required.

INVESTIGATION OF ENVIRONMENTAL RADIOACTIVITY AT A DECOMMISSIONED URANIUM MINE IN SOUTHERN CHINA.

An environmental radioactivity survey was performed on a uranium mine that has been decommissioned for >10 y. According to the characteristics of this uranium mine, the relevant parameters, such as the surface-absorbed dose rate in air, the radon and radon progeny concentrations in the air, the radon exhalation rate from the soil surface and the concentrations of natural radionuclides in soil and surface water, were measured. The results show that the maximum annual effective doses of residents and employees in the uranium mine caused by radon and radon progenies inhalation were 1.48 and 1.74mSv, respectively, and the maximum annual effective doses of residents and employees caused by gamma-ray external radiation were 1.16 and 1.32mSv, respectively.

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.
 J. Bangladesh Acad. Sci. 45(1); 95-104: June 2021

INVESTIGATION AND ANALYSIS OF ENVIRONMENTAL RADIOACTIVITY LEVELS AT TYPICAL URANIUM MINES IN THE SOUTH OF CHINA.

The environmental radioactivity levels of two typical uranium mines in the south of China were investigated and analysed. According to the characteristics of uranium mines, the relevant parameters, including the surface gamma ray dose rate, concentration of radon in the air and concentration of radionuclides in the soil and surface water, of two uranium mines were evaluated and analysed. The results show that residents in the mining area were exposed to average maximum annual effective doses of 1.69 and 1.58mSv due to the inhalation of radon and its daughters, while the employees received 2.59 and 1.87mSv, respectively. Residents in the mining area were exposed to average maximum annual effective doses of 0.77 and 0.69mSv due to gamma ray, while the employees received 1.64 and 1.33mSv, respectively.

Absorbed doses of the taxi drivers in the vicinity of the patients that were injected for SPECT imaging: a Monte Carlo study

Nuclear medicine is a branch of medical science that uses radionuclides for diagnosing and treatment of diseases. In this paper, the dose of the different organs and annual effective dose of a taxi driver were calculated in a vicinity of a patient that was injected for the brain, kidney, and liver SPECT by using Monte Carlo method. Two MIRD phantoms were simulated as a driver and patient, including the simple body of a taxi in MCNPX2.4 code. The radioactivity distributions were obtained from ICRP reports and sources were defined according to them. The patients that have undergone the brain, kidney and liver SPECT with the injection of different activities of the 99mTC radioisotope were included in this study. The injected activities were 740 MBq, 185 MBq, and 333 MBq for the brain, kidney, and liver SPECT respectively. Annual effective doses were calculated for one 99mTC injected patient per working day with an assumption of 30 min ride duration. The maximum annual effective doses of the taxi driver were 2.31, 0.54, and 1.21 $$\upmu \mathrm{S}\mathrm{v}$$ in the vicinity of the patients that were injected for brain, kidney, and liver SPECT respectively. The maximum annual effective dose of the taxi driver is larger than the ICRP recommended data up to 2.3 times. We recommend that to reduce dose, the patient should sit in “position 2”, farthest back seat with respect to the driver, and the driver’s seat could have some shielding place around it.

Assessment of natural radioactivity levels in soil sample from Botteng Utara Village, Mamuju Regency Indonesia

High background radiation areas usually are correlated to the high concentration of primordial radionuclides activity from Uranium/Thorium series and 40K. This paper reported the natural radioactivity level in soil sample was taken from Botteng Utara village area. The activity of primordial radionuclide such as 226Ra, 232Th and 40K were investigated from the soil by gamma spectrometry. In order to evaluate the radioactivity levels of the area, Radium equivalent activity (Raeq), the absorb dose rate (D), the annual effective dose rate (E), the external hazard index (Hex), and internal hazard index (Hin) were calculated and compared with the internationally approved value. The concentration of 226Ra, 232Th and 40K measured by gamma spectrometry are lies in the range 268.90 to 2921.17, 993.07 to 3153.81, and 115.72 to 438.26 Bq.kg−1respectively. The average and maximum annual effective dose received by Botteng Utara resident from terrestrial gamma rays are 10.40 and 18.62 mSv y−1, which is the maximum received by resident of Tande-Tande hamlets. This present work clarify that Botteng Utara is an area with high background radiation exposure from primordial radionuclides activity.

Radiation Exposure of Patient and Operating Room Personnel by Fluoroscopy and Navigation during Spinal Surgery

Intraoperative radiography imaging is essential for accurate spinal implant placement. Hazards caused by ionizing radiation raised concern on personnel’s work life long exposure in the operating room (OR). To particularize a cumulative risk estimation of radiation of personnel and patient, depending on used methods (C-arm fluoroscopy, O-arm navigation) and patient characteristics during spinal surgery, detailed investigation of radiation exposure in a clinical setting is required. Lumbosacral dorsal spinal fusion was performed in 37 patients (19 navigated, 18 fluoroscopy) during this prospective study. Radiation exposure was measured on several body regions with thermoluminescent dosimeters on patient and OR personnel (surgeon, assistant, sterile nurse, radiology technologist). Comparison between patient characteristics and radiation exposure was included. The highest patients values were measured in the surgery field and gonads area during navigation (43.2 ± 19.4 mSv; fluoroscopy: 27.7 ± 31.3 mSv; p = 0.02), followed by the thoracic region during fluoroscopy (7.7 ± 14.8 mSv; navigation: 1.1 ± 1.0 mSv; p = 0.06), other measured regions can be considered marginal in comparison. Amongst OR personnel exposure of the surgeon was significant higher during fluoroscopy (right hand: 566 ± 560 µSv and thoracic region: 275 ± 147 µSv; followed by thyroid and forehead) compared to navigation (right finger: 49 ± 19 µSv; similar levels for all regions; p < 0.001 in all regions). When compared to the surgeon, other OR personnel had significantly lower radiation doses on all body regions using fluoroscopy, and similar dose during navigation. The highest eye’s lens region value was measured during fluoroscopy for the patient (185 ± 165 µSv; navigation: 205 ± 60 µSv; p = 0.57) and the surgeon (164 ± 74 µSv; navigation: 92 ± 41 µSv; p < 0.001). There was a significant correlation between patient BMI and radiation exposure to the surgery field during fluoroscopy. To our knowledge, these data present the first real life, detailed comparison of radiation exposure on OR personnel and patients between clinical use of navigation and fluoroscopy. Although patient’s radiation dose is approximately 3-fold during navigation compared to the fluoroscopy, we found that a spinal surgeon could perform up to 10-fold number of surgeries (10.000 versus 883) until maximum permissible annual effective radiation dose would be reached. Especially for a spinal surgeon, who is mainly exposed amongst OR personnel, radiation prevention and protection must remain a main issue.

Internal exposure risk due to radiocesium and the consuming behaviour of local foodstuffs among pregnant women in Minamisoma City near the Fukushima nuclear power plant: a retrospective observational study

ObjectivesThis study aimed to evaluate the internal cesium (Cs) level among pregnant women in Minamisoma City (the area straddling the evacuation zones) over a 5-year period after Japan’s 2011 Fukushima...

External dose evaluation based on detailed air dose rate measurements in living environments

A method was devised to estimate the realistic external doses of residents expected to return to their homes after evacuation orders are lifted. For 196 residents expected to return to six towns and villages, surveys were administered in FY 2014–2016. After interviewing residents about their expected life patterns after their return, detailed air dose rate measurements were taken along their reported personal routes representing patterns of movement in their daily life. The maximum and average annual additional external effective dose were estimated at 4.9 mSv and 0.86 mSv, respectively. Although the mean values and dispersion of external effective doses differed depending on the level of evacuation, for 93.3% of all residents, the estimated annual additional external effective doses were less than 2 mSv. Measuring air dose rates inside houses was found to be important to obtain a realistic evaluation of the external exposure dose because our research revealed that the average time spent indoors was 87% of the total living time. Moreover, the average exposure dose at home accounted for 66.8% of the annual exposure dose.

Public ingestion exposure to 226Ra in Ramsar, Iran

Ramsar, in the north of Iran by the Caspian Sea, has been known for the highest natural radiation background on Earth due to the local geology and hydrogeology. The residents and visitors use the hot springs that distribute the natural radionuclides especially 226Ra and its decay products in the areas. Many studies have been undertaken to measure the absorbed dose rate in Ramsar's air, however, no survey has been done to assess public internal exposure from ingestion of natural radionuclides, such as, a broad survey for 226Ra was conducted in foodstuffs and drinking water. This study presents the results of public annual activity intake (Bq) and effective dose (μSv) from ingestion of 226Ra in foodstuffs and drinking water in Ramsar city. The total mean annual intake for adults was found to be 24.8 Bq. The annual average effective dose due to ingestion exposure to 226Ra was found to be 6.9 μSv for adults that were slightly more than the estimated global averages reported by UNSCEAR, 2000 (6.3 μSv). The contribution of drinking water and foodstuffs represent respectively about 30% and 70% of the total mean annual effective dose due to 226Ra. The highest effective dose from ingestion of 226Ra for adults was estimated to be 80.6 μSv y−1. Based on the results of this study, even with the largest 226Ra value in our survey, maximum annual effective dose due to consumption of foodstuffs and drinking water for children was 164.2 μ b Sv y−1.

ASSESSMENT OF ANNUAL EFFECTIVE DOSE FROM EXPOSURE TO NATURAL RADIOACTIVITY SOURCES IN A CASE-CONTROL STUDY IN BIHOR COUNTY, ROMANIA.

The purpose of the article is to evaluate the annual effective dose for 80 women divided into two samples; one sample located in the former uranium Băiţa-Ştei area, hereinafter referred to as case sample, respectively for a control sample, located in the same county, but exposed in most cases to indoor radon activity concentrations <300 Bq m-3. In this regard, the homemade 'RaThoGamma' kit was used, which contained two thermoluminescent dosimeters, a CR-39 track detector (RSKS) for indoor radon activity concentration, two CR-39 track detectors (Radtrak2®/ Radtrak2T®) for radon and thoron activity concentrations as well as Direct Radon Progeny Sensors/Direct Thoron Progeny Sensors for measuring time-averaged radon and thoron progenies concentrations. In addition, a total of 80 water samples were collected in order to evaluate the ingestion dose due to radon and radium activity concentrations in drinking water. The maximum total annual effective dose in the control sample was 14.1 mSv, while in the case sample the maximum annual effective dose was 60.5 mSv. This difference is mainly due to radon progenies inhalation. Other pathways did not show a statistically significant difference between the two samples, showing a minor contribution to the annual effective dose.

Simulation of radionuclide atmospheric dispersion and dose assessment for inhabitants of Tehran province after a hypothetical accident of the Tehran Research Reactor.

Radiological dose assessment is one of the main categories of safety assessment for nuclear reactors and facilities. The radiation risks to the public and to the environment that may arise from these facilities have to be assessed and, if necessary, controlled. The main objective of this paper is the assessment of radiation doses to residents of Tehran province after a hypothetical accident of the Tehran Research Reactor (TRR) including the determination of any protective actions that might be needed for the benefit of people's health. The concentration of radionuclides in air and deposited on the ground surface as a result of a hypothetical radionuclide release from the TRR, following a hypothetical accident scenario, have been calculated by the HYSPLIT computer code. Simulations were performed using selected source terms taken from the TRR Final Safety Analysis Report (FSAR). Meteorological data of the Air Resources Laboratory of the National Oceanic and Atmospheric Administration (NOAA) have been used in these calculations. The simulation results indicate that maximum annual total effective dose equivalent values for the residents of the Tehran province are less than the protective action dose limits. Thus, it is concluded that during this hypothetical accident in the TRR, required safety due to public radiation is achieved and the residents of Tehran province are safe under a TRR accident condition.

Measurement of Radon Gas Concentrations and Hazard Effects in Underground Water Samples in Karbala Governorate of Iraq

One of the most characterizations of social health is the existence availability of sources irrigation water. Since the main source of water, contamination is radon gas. Six regions in Karbala province in Iraq were chosen to evaluate Radon level in underground water-samples by using (SSNTD-CR-39) Detector. The current measurements showed that highest level was in Al-Horr region to be 4.152±2.2Bq/L, where lowest concentration was in Hay-Rumdan 2.165±1.6Bq/L. The maximum Annual-Effective Dose (AED) was found in Al-Horr to be 14.34±3.5μSv/y, whereas the minimal value indicated at Hay-Rumdan 8.66±3.1μSv/y. In general, it has been found that Radon-level concentration, in the studied groundwater-samples, was less than allowed permissible value 11.1Bq/L and annual effective-doses were below the recommended international value 1mSv/y. Therefore, groundwater in all underground water studied in Karbala province is safe where the focus of radon obsession is not a public concern.

Assessment of Occupational Exposure to External Radiation among Workers at the Institute of Radiotherapy and Nuclear Medicine, Pakistan (2009-2016)

Introduction: Assessment of occupational exposure to external radiation and the analysis of associated trends are imperative to observe changes that have taken place over time due to regulatory operations or technological advancements. Herein, we describe the occupational radiation exposure to workers employed in Nuclear Medicine (NM), Radiotherapy (RT), and Diagnostic Radiology (DR) departments at the Institute of Radiotherapy and Nuclear Medicine, Peshawar, Pakistan, and to evaluate the related trends during 2009-2016. Materials and Methods: A retrospective analysis of the dose records of 4320 film dosimeters was performed during 2009-2016. The analyzed quantities included annual collective effective dose, annual average effective dose, distribution of workers, and their annual average effective doses in various effective dose intervals, as well as the maximum and minimum annual individual effective doses. Results: The annual average effective doses in RT, NM, and DR were within the ranges of 1.07-1.45, 1.25-1.55, and 1.03-1.60 mSv, respectively. The majority (90%) of the workers received effective doses in the interval of 1-4.99 mSv, while 10% of the workers received doses within the range of the minimum detectable level-0.99 mSv. The minimum and maximum annual individual effective doses were 0.30 mSv and 3.96 mSv as recorded in RT and NM, respectively. The annual average effective doses measured for NM, RT, and DR were 1.39, 1.23, and 1.30 mSv, respectively. These values are comparable with the worldwide annual average effective doses. Conclusion: All the workers received doses below the annual dose limit. The status and trends of doses showed that radiation protection conditions were adequate.

RADIATION HYGIENIC MONITORING AND ASSESSMENT OF POPULATION DOSES IN RADIOACTIVELY CONTAMINATED AREAS OF TULA REGION

The goal. The analyses of radiation hygienic monitoring conducted in Tula region territories affected by the Chernobyl NPP accident regarding cesium-137 and strontium- 90 in the local foodstuffs and the analyses of populational annual effective dose. The materials and methods. The survey was conducted in Tula Region since 1997 to 2015. Over that period, more than fifty thousand samples of the main foodstuffs from the post-Chernobyl contaminated area were analyzed. Simultaneously with that, the external gamma - radiation dose rate was measured in the fixed control points. The dynamics of cesium -137 and strontium-90 content in foodstuffs were assessed along with the maximum values of the mean annual effective doses to the population and the contribution of the collective dose from medical exposures into the structure of the annual effective collective dose to the population. The results. The amount of cesium-137 and strontium -90 in the local foodstuffs was identified. The external gamma- radiation dose rate values were found to be stable and not exceeding the natural fluctuations range typical for the middle latitudes of Russia’s European territory. The maximum mean annual effective dose to the population reflects the stable radiation situation and does not exceed the permissible value of 1 mSv. The contribution of the collective dose from medical exposures of the population has been continuously reducing as well as the average individual dose to the population per one medical treatment under the annual increase of the medical treatments quantities. The conclusion. There is no exceedance of the admissible levels of cesium-137 and strontium- 90 content in the local foodstuffs. The mean annual effective dose to the population has decreased which makes it possible to transfer the settlements affected by the Chernobyl NPP accident to normal life style. This is covered by the draft concept of the settlements’ transfer to normal life style.

Whole body counter assessment of internal radiocontamination in patients with end-stage renal disease living in areas affected by the Fukushima Daiichi nuclear power plant disaster: a retrospective observational study

ObjectiveTo assess internal radiocontamination of patients with end-stage renal disease (ESRD) who were regularly taking haemodialysis (HD) and living in areas affected by the crippled Fukushima Daiichi nuclear plant after...

Minimal Internal Radiation Exposure in Residents Living South of the Fukushima Daiichi Nuclear Power Plant Disaster.

Following the Fukushima nuclear power plant disaster, assessment of internal radiation exposure was indispensable to predict radiation-related health threats to residents of neighboring areas. Although many evaluations of internal radiation in residents living north and west of the crippled Fukushima nuclear power plant are available, there is little information on residents living in areas south of the plant, which were similarly affected by radio-contamination from the disaster. To assess the internal radio-contamination in residents living in affected areas to the south of the plant or who were evacuated into Iwaki city, a whole body counter (WBC) screening program of internal radio-contamination was performed on visitors to the Jyoban hospital in Iwaki city, which experienced less contamination than southern areas adjacent to the nuclear plant. The study included 9,206 volunteer subjects, of whom 6,446 were schoolchildren aged 4–15 years. Measurements began one year after the incident and were carried out over the course of two years. Early in the screening period only two schoolchildren showed Cs-137 levels that were over the detection limit (250 Bq/body), although their Cs-134 levels were below the detection limit (220 Bq/body). Among the 2,760 adults tested, 35 (1.3%) had detectable internal radio-contamination, but only for Cs-137 (range: 250 Bq/body to 859 Bq/body), and not Cs-134. Of these 35 subjects, nearly all (34/35) showed elevated Cs-137 levels only during the first year of the screening. With the exception of potassium 40, no other radionuclides were detected during the screening period. The maximum annual effective dose calculated from the detected Cs-137 levels was 0.029 and 0.028 mSv/year for the schoolchildren and adults, respectively, which is far below the 1 mSv/year limit set by the government of Japan. Although the data for radiation exposure during the most critical first year after the incident are unavailable due to a lack of systemic measurements, the present results suggest that internal radio-contamination levels more than one year after the incident were minimal for residents living south of the crippled Fukushima nuclear plant, and that the annual additional effective doses derived from internal Cs contamination were negligible. Thus, internal radio-contamination of residents living in southern radio-contaminated areas appears to be generally well controlled.

OCCUPATIONAL DOSE ASSESSMENT IN INTERVENTIONAL CARDIOLOGY IN SERBIA.

The objective of this work is to assess the occupational dose in interventional cardiology in a large hospital in Belgrade, Serbia. A double-dosimetry method was applied for the estimation of whole-body dose, using thermoluminescent dosemeters, calibrated in terms of the personal dose equivalent Hp(10). Besides the double-dosimetry method, eye dose was also estimated by means of measuring ambient dose equivalent, H*(10), and doses per procedure were reported. Doses were assessed for 13 physicians, 6 nurses and 10 radiographers, for 2 consequent years. The maximum annual effective dose assessed was 4.3, 2.1 and 1.3 mSv for physicians, nurses and radiographers, respectively. The maximum doses recorded by the dosemeter worn at the collar level (over the apron) were 16.8, 11.9 and 4.5 mSv, respectively. This value was used for the eye lens dose assessment. Estimated doses are in accordance with or higher than annual dose limits for the occupational exposure.