Protocol for assessing and managing radon gas exposure risks in caves: A case study of Altaomira and Paleolithic cave art of Northern Spain World Heritage Site

Human exposure to radon radiation geohazard in Rong Cave, Dong Van Karst Plateau Geopark, Vietnam

Radon continuous monitoring in Altamira Cave (northern Spain) to assess user's annual effective dose

Routine monitoring of occupational radiation exposure is done primarily to demonstrate compliance with dose limits. Statistical analysis of past and present dose records provides a useful tool in the management of institutional radiation safety programs. In this study, a statistical analysis of annual dose records from 1985-1999 from a large tertiary care medical center with a cyclotron and radiopharmaceutical production facility is performed. A total of 6,089 annual dose records, categorized into ten occupational groups, were included in the analysis. Dose distribution is skewed, with 85% of workers receiving an annual dose of less than 1.0 mSv, while 1.3% have doses > or =10 mSv. The mean annual dose of all monitored workers during this 15-y period ranged from 0.5 to 1.2 mSv. Large variation in the mean annual dose exists among the different occupational groups. Four occupational groups were identified as relatively highly exposed, namely cyclotron and radiopharmaceutical production, cardiac catheterization, nuclear medicine, and diagnostic radiology. These four occupational groups also showed different trends in the mean annual dose. A correlation study showed that total annual collective dose has no linear association with the number of monitored workers, the number of measurably exposed workers, or the number of workers with annual dose between 0.1 to <10 mSv. Moderate correlation (r = 0.64) was observed between the annual collective dose and the collective dose of workers with an annual dose between 0.1 to <10 mSv. A strong and significant correlation (r = 0.95) exists between the total annual collective dose and both the number of workers with annual dose of > or =10 mSv and the corresponding collective dose due to these highly exposed workers. Although the fraction of these highly exposed workers is small (about 1%), they have a significant impact on the total collective dose and their contribution can be as high as 50%. Workers with annual dose of > or =10 mSv tend to concentrate in a few identified occupational groups and not across all occupational groupings. The cyclotron and radiopharmaceutical production department is of particular concern due to its high individual dose levels and increasing mean annual dose trend for the last 5 y. Radiochemists and cyclotron engineers tend to receive an annual dose exceeding the dose limit. A plot of the collective dose of highly exposed workers vs. the total collective dose shows that if a dose constraint of 10 mSv is imposed on highly exposed occupational groups, the total collective dose is expected to be about 200 person-mSv.

Assessment of radiation exposure in a nuclear medicine department of an oncology hospital

Physicians work hours: desperately seeking evidence

The International Commission on Radiological Protection (ICRP) issued its Publication 137, Occupational Intakes of Radionuclides: Part 3 in which the radon equilibrium factor is fixed as 0.4 for tourist caves; however, several studies have reported a different value for the factor and its seasonal variation has also been observed. In this study, the radon concentration, equilibrium equivalent radon concentration and meteorological data were measured, and the equilibrium factor was evaluated in a tourist cave, Gyokusen-do Cave located in the southern part of Okinawa Island in southwestern Japan. Radon concentrations were measured with an AlphaGUARD and their corresponding meteorological data were measured with integrated sensors. Equilibrium equivalent radon concentration was measured with a continuous air monitor. The measured radon concentrations tended to be low in winter and high in summer, which is similar to previously obtained results. By contrast, the equilibrium factor tended to be high in winter (0.55 ± 0.09) and low in summer (0.24 ± 0.15), with a particularly large fluctuation in summer. It was concluded that measurements in different seasons are necessary for proper evaluation of radon equilibrium factor.

This study aimed to evaluate indoor radon concentrations in Riobamba canton, Ecuador's central Andean region, and to analyze two factors influencing their variability: surface geology and the age of the dwelling. Radon measurements were conducted in 225 homes using passive monitoring systems, while continuous laboratory monitoring with a Lucas Pylon cell was employed to assess temporal patterns. Concentrations ranged from 9.4 to 152.8Bq/m3, with an arithmetic mean of 49.5 ± 26.6Bq/m3. Ninety-four percent of the homes had radon concentrations below the World Health Organization's recommended reference level of 100Bq/m3. The calculated average annual effective dose was 1.3 ± 0.7mSv/year, well below the International Commission on Radiological Protection action level of 10mSv/year. A statistically significant association was identified between radon levels and the age of the homes; however, no relationship was found between radon levels and the surface geology beneath the buildings. The highest concentrations were observed in houses built before 1925 using traditional techniques such as bahareque, adobe and cancagua. Seasonal analysis revealed minimal variability throughout the year (dry season mean/rainy season mean = 1.04), a result that differs from the well-documented behavior in regions with marked seasonal variability and suggests that seasonal correction factors are not necessary. In addition, a diurnal pattern was evident, which was inversely correlated with indoor temperature and directly correlated with relative humidity. These findings enhance the understanding of radon behavior in the tropical Andean climates characterized by low seasonal variability.

Oil and gas production processing operations have been known to produce a large amount of naturally occurring radioactive materials (NORMs) at elevated concentrations as by-product waste streams. This means that TE-NORM wastes from the oil & gas industry may generate radiation exposure levels, which require attention and continuous monitoring during NORM decontamination of oil and gas equipment. This exposure is mostly caused by external and internal radiation coming from the 226Ra &228Ra (U-238 and Th -232 series) radionuclide and their progenies. This study focuses on follow up the annual effective dose for workers during decontaminating naturally occurring radioactive materials (NORM) of oil and gas equipment. The external effective dose was evaluated using thermoluminescence detector (TLD). The obtained data showed that the range of the annual dose was from 1.07 to 1.78 mSv and the average dose of the ten workers under investigation was 1.4 ±0.24 mSv. The average dose is about 7 % of the occupational annual dose limit. We conclude that protective measures against external and internal contamination helped in the protection of the workers against NORM hazards)

Although the perfomance indicators of the nuclear power plants in Korea show optimal, it requires detailed analysis and discussion centered on the radiation dose. As analysis methods, analysis on the radiation dose of nuclear power plants over the past five years was assessed by comparing the relevant radiation dose of radiation workers and per capita average annual radiation dose of the world's major nuclear power stations was also analyzed. The radiation workers over the annual radiation dose limit of 50 mSv were not. The contrast ratio of the radiation exposure according to the reactor type was the normal operation of PHWR was 6.2% higher than those of the PWR. This shows the radiation work of PHWR during normal driving operation is much more than those of PWR. According to the Performance Indicators of the World Association of Nuclear Operator, the annual radiation dose per unit in 2013 showed 527 man-mSv of Korea is the best country among the major nuclear power generating states, the world average was 725 man-mSv. The annual per capita radiation dose is about 80% less than 1 mSv of the public dose limit and also the average per capita dose showed a very low level as 0.82 mSv. Workers in related organizations showed 1.07 mSv, the non-destructive inspection agency workers showed 3.87 mSv. The remarkable results were due to radiation reduced program such as development of radiation shielding and radiation protection. In conclusion, the radiation exposured dose of nuclear power plants workers in Korea showed a trend which is ideally reduced. But more are expected to be difficul and the psychological insecurity against the operation of the nuclear power plants is existed to the residents near the nuclear power plants. So the radiation dose reduction policy and radiation dose follow up study of nuclear power plants will be continously excuted.

目的 为了宇宙辐射防护管理,计算飞行人员个人宇宙辐射年均受照有效剂量. 方法根据飞行指令数据使用软件CARI-6计算飞行航线的宇宙辐射有效剂量和乌鲁木齐地区地面的宇宙辐射有效剂量, 由此计算个人年均受照有效剂量. 结果乌鲁木齐地区地面个人年均受照有效剂量为0.420 mSv·a-1,新疆地区全部航线1997至1999年年均宇宙辐射有效剂量率为2.381 μSv·h-1 (最大3.640 μSv·h-1,最小0.330 μSv·h-1),被检测飞行人员年均受照有效剂量为2.193 mSv·a-1(最大4.419 mSv·a-1,最小0.887 mSv·a-1). 结论估算的234个受检飞行人员的年均受照有效剂量均小于国际放射防护委员会(ICRP)建议的限值20 mSv·a-1。

The distribution of artificial radionuclide 137 Cs in fish from the seas surrounding the Korean Peninsula was investigated to estimate the bioaccumulation and annual effective dose rate according to size. The activity of 137 Cs in the muscles of seven fish species (armored weaselfish, croaker, flounder, hairtail, catfish, conger, and mackerel) was in the range of 50–269 mBq kg −1 , which was similar to that observed in Korean Seas between 2017 and 2021 (&lt;22 to 288 mBq kg −1 ). The results showed no particular enrichment pattern based on the fish body size. The activity of 137 Cs in dissected parts, such as the skin, inner organs, gills, and gonads, was in the range of 29–311 mBq kg −1 , and the parts where 137 Cs was most enriched varied among fish species and growth stages. The annual effective dose rate of 137 Cs provided by the seafood consumption of these fish in South Korea was estimated to be 0.10–4.81 × 10 −6 mSv y −1 , which is insignificant relative to that of natural radionuclides such as 210 Po. Thus, these results indicated that annual dose rate by the 137 Cs dose not have a noticeable impact on marine organisms, however, continuous monitoring with various species of fish is necessary to evaluate possible future nuclear power plant accidents.

On 19 September 2021, the largest historic eruption of La Palma began, named the Tajogaite volcano. It was active for 85 days, ending on 13 December 2021. During eruptions, the exposure to natural pollutants rises above background levels due to gas emissions and particulate matter (ash and aerosols) into the atmosphere. Moreover, rock fracturing due to magma injection and seismic activity associated with the eruptive phenomena can increase the ground permeability, having a potential effect on radon (222Rn) emissions. During the eruptive and post-eruptive period of the Tajogaite volcano, 222Rn measurements were performed across the affected areas to assess the possible radiological impact of this volcanic episode on La Palma inhabitants.During the first weeks of the eruption, 88 Solid State Nuclear Track (CR-39-SSNT) detectors were deployed at workplaces and dwellings, mainly located in the vicinity of the eruption, though several detectors were also placed in more distant areas for comparison. These detectors were exposed for ca. 90 days, from September 2021 to January 2022, though only 77 detectors could be retrieved as the rest were buried by the lavas. In addition, 3 portable RadonScout devices (SARAD GmbH) were used for continuous monitoring (1 h integration time) of radon and environmental parameters (air temperature, humidity and barometric pressure). They were installed inside 3 buildings located 2.8-5 km from the volcano.Eighty percent of the CR-39-SSNT radon data were below the reference level of 300 Bq/m3 (Directive 2013/59/Euratom). Of the remaining detectors, a large percentage of radon levels were above 300 Bq/m3 in the Aridane valley, an area close to the volcano, and with a clear spatial pattern showing higher levels of 222Rn at shorter distances to the eruptive centre. Continuous monitoring of radon showed low 222Rn levels (&lt; 300 Bq/m3) at the two sites furthest from the volcano, with fluctuations highly correlated with environmental variables. Several anomalies of 222Rn reaching up to 4000 Bq/m3 were detected during the eruptive period in the monitoring station located closer to the eruptive centre, unrelated to the observed environmental variables. These anomalies were synchronous with the occurrence of large explosive events and phreatomagmatic pulses during the eruption.The computed effective dose due to the contribution of 222Rn during the 3 months of eruption was 0.3 mSv, which, extrapolated to the annual reference value, provides an estimated effective dose of 0.9 mSv/year. This value is 50% lower than the estimated worldwide annual average dose from natural and artificial radiation sources (2.4 mSv/year) (UNSCEAR 2000). Thus, radon levels during the Tajogaite eruption did not lead to a significant increase in exposure level to this radioactive gas. However, transient radon bursts have been recorded associated with several phases of the volcanic activity.&amp;#160;AcknowledgmentsThis study was supported by the Spanish Ministry of Science and Innovation (BOE-A-2021-20262).

Determination of natural thorium isotopes (230Th and 232Th) in calcium and magnesium supplements and the potential effective exposure radiation dose for human

Despite the mandatory use of medical disposable protective clothing to protect against infectious hazards, how to determine optimal safe working hours induced by physical fatigue while wearing medical disposable protective clothing remains unknown. Driven by these questions, here we quantify the extent of physical fatigue experienced by medical staff wearing medical disposable protective clothings in isolation wards to identify a safe work duration. Eight healthy males were subjected to light (2.1 km/h) and moderate (4.3 km/h) treadmill exercises while wearing two different ensembles. Four physiological (tympanic temperature Tcore, mean skin temperature Tsk, heart rate, and sweat loss) and two subjective indicators (thermal sensation and humidity sensation) were measured. We then introduced a discrete gray model(1,1) to determine safe working hours. The study indicated that even at lower temperatures, prolonged wearing of medical disposable protective clothing could significantly affect physiological indicators such as Tcore and Tsk ( p &lt; 0.001), with Tcore being the predominant factor limiting safe working hours. Regarding medical disposable protective clothing-1-light, medical disposable protective clothing-1-moderate, medical disposable protective clothing-2-light, and medical disposable protective clothing-2-moderate intensity activities, the safe working hours were 6.33, 2.83, 2.83, and 2.25 h. This article presented a new approach to determining safe working hours for wearing medical disposable protective clothing from physiological thermal limits with small sample data. However, this is a preliminary study, and further validation of the prediction model through additional experiments is necessary.

Radon levels in a Pennsylvania dial painting facility from measurements by Victor Hess