Radon-222 and 226Ra concentrations in mineralized groundwaters of Gorzanów (Kłodzko Basin, Sudeten Mountains, SW Poland)

This work characterizes the occurrence of radionuclides ²²²Rn and ²²⁶Ra in the mineralized groundwaters of Gorzanów. The village is situated in the Sudeten Mountains, which are known in Poland for having increased concentrations of the aforesaid radionuclides in their groundwaters. However, in Gorzanów, the measured concentrations of ²²⁶Ra were low both in the reservoir rocks and mineralized waters. Consequently, the ²²²Rn concentration in the groundwaters also turned out to be low. The ²²⁶Ra content of these waters should mainly be associated with the dissolution of this nuclide, together with other main ions, at large depths, at slightly enhanced temperature. Radon-222, on the other hand, penetrates into the water during its outflow to the surface, in the zones of intensive friable deformations near fault zones. Thus, in the groundwaters of Gorzanów, the concentrations of these nuclides, subsequent in the uranium series, do not have a common genesis and they are not correlated with each other.     

Measurement of 222Rn and 226Ra in municipal supply tap water to evaluate their radiological impacts

ABSTRACT

Radon (²²²Rn) and its parent radionuclide Radium (²²⁶Ra) are classified as carcinogen. Human exposes to radon in water via inhalation and ingestion, although ingestion is the only way for radium to enter the human body. In this research, tap water collected from Bornova distinct was studied to determine the concentration of radon (²²²Rn) and radium (²²⁶Ra) for evaluating their radiological impact. For this reason, the annual effective doses for ingestion and inhalation were estimated. The measurements were performed using a collector chamber method. The mean concentrations of ²²²Rn and ²²⁶Ra were determined as 0.85 and 0.76 Bq/L, respectively. It can be stated that the ²²²Rn and ²²⁶Ra concentrations of tap waters here are lower than the international reference levels. Obtained concentration levels were applied to estimate annual effective dose due to the inhalation and ingestion. The dose values are also found to be lower than the recommended maximum values. On the other hand, it should be considered that consumption of these waters (2 L) and average radon and radium concentrations of water are the significant factors for estimating doses.     

226Ra and 222Rn concentrations of spring waters in Balaton Upland of Hungary and the assessment of resulting doses

²²²Rn and ²²⁶Ra concentration of 18 frequently visited and regularly used, consumed spring waters on the Balaton Uplands have been measured by radon emanation method and alpha-spectrometry. ²²²Rn concentration varied between 1.5-55 Bq/l while ²²⁶Ra concentration between -601 mBq/l. The expected dose, between 14.1-119 mSv/y, has been assessed from the value of concentration supposing a daily consumption of 1 liter.     

Natural radioactivity of spring water used as spas in Spain

Spring waters used as spas may contain significant amounts of natural radionuclides, so, in some circunstances, a radiation protection issue can arise for the population and/or the spas workers. EU has identified some groups of employees to be exposed to natural radiation in the 1996 Euratom Directive. Among these are workers of thermal spas who may be exposed to high radiation doses due to high radon concentrations in indoor air. In order to evaluate the potencial risk of the spring waters used as spas, gross-α and gross-β activity, ²²⁶Ra and ²²²Rn concentration levels were measured in 82 spas all over the country. Gross-alpha and gross-beta concentrations ranged from LLD to 17 Bq·l⁻¹ and from LLD to 60 Bq·l⁻¹, respectively. ²²⁶Ra concentrations ranged from <4 to 3,660 mBq·l⁻¹. ²²²Rn concentrations ranged from <4 to 1868 Bq·l⁻¹. Correlations between ²²⁶Ra concentrations and gross-α activity were obtained.     

Calibration and optimization of alpha-beta separation procedures for determination of radium/radon in single- and two-phase liquid scintillation systems

Liquid scintillation alpha beta discrimination technique based on pulse shape analysis (PSA) was evaluated for determination of ²²⁶Ra and ²²²Rn in water samples. In view of the significance of calibration, for the reliable and precise determination of ²²⁶Ra and ²²²Rn concentrations in water samples, calibration procedures were standardized for single and two phase systems using Quantulus 1220 liquid scintillation counter. PSA optimization and efficiency calibrations were performed using ²²⁶Ra standard rather than conventionally used pure alpha and beta standards and substantiated by measuring the activity concentrations of ²²⁶Ra and ²²²Rn in the spiked water samples.     

Preparation and analysis of <Superscript>226</Superscript>Ra-<Superscript>222</Superscript>Rn emanation standards for calibrating passive radon detectors

Summary In order to calibrate vials containing charcoal for measurement of radon, emanation sources of radon were produced in-house using ²²⁶Ra salts. Calibrated emanation standards containing solution of ²²⁶Ra(NO₃)₂ absorbed into inorganic compounds were prepared. The emanation coefficient of ²²²Rn for these standards vary from 0.23-0.25. The emanation sources were found to be suitable for calibrating radon monitors.     

Natural radioactivity levels of limestone rocks in northern Iraq using gamma spectroscopy and nuclear track detector

The activity concentration of radionuclides, such as ²³⁸U, ²²⁶Ra and ⁴⁰K of limestone rocks in northern Iraq was measured using gamma spectroscopy. The radionuclide activities were obtained and discussed. CR-39 nuclear track detector was used to measure the radon exhalation rates as well as the effective radium contents of these samples and are found to correspond with uranium concentration values measured by NaI(Tl) detector in the corresponding limestone rocks samples. The absorbed gamma dose rates in air due to the presence of ²³⁸U, ²²⁶Ra, ⁴⁰K and cosmic ray contribution varied between 105.3 and 223.11 nGy/h. The annual effective dose of each sample has been calculated. The correlation between activities of ²²⁶Ra, ²²²Rn exhalation rates and ²³⁸U is explained. Results show a symmetrical distribution of activity concentrations of primordial of radionuclides in selected samples. The values of all studied radionuclides are considered to be a typical level of natural background and compared with results of similar investigations carried out else where.     

Radium isotopes and <Superscript>222</Superscript>Rn in Austrian drinking waters

The activity concentrations of the Ra isotopes, ²²⁶Ra and ²²⁸Ra, as well as of ²²²Rn were measured in Austrian tap waters. Rn was extracted into a mineral oil cocktail not miscible with water and measured by liquid scintillation counting using pulse-shape analysis for α/β-separation. Ra isotopes were co-precipitated with BaSO₄ or concentrated by filtration through an element specific filter. EDTA solution was used to redissolve the precipitate as well as to release the Ra from the filter. After mixing with a cocktail, the EDTA solution was measured by liquid scintillation counting, too. From our results the effective ingestion doses for adults and 3 months old babies were calculated.     

Radioactivity of spring and surface waters in the region of the uranium ore deposit at Žirovski vrh

Data are presented on²²²Rn,²²⁶Ra, natural uranium concentrations and gross beta activity of spring and surface waters in the region of the uranium ore deposit at Žirovski vrh. The concentrations were found to be relatively low. There is some increase in the vicinity of the explorative Uranium Mine but is, at least up till now, only of a local character.     

Radioactive contamination of the environment as a result of uranium production: a case study at the abandoned Lincang uranium mine,Yunnan Province,China

The distribution of radioactive pollutants, such as²²²Rn, U, Th and²²⁶Ra in the air, surface waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studied. The mechanical, geochemical and biogeochemical processes responsible for the transport and fate of the radioactive elements are discussed based on the monitoring data. The pollutants concentrations of effluents from the mine tunnels were dependent on pH and which were controlled by biochemical oxidation of sulfide in the ore/host rocks. Radon anomalies in air reached 4 km from the tailings pile depending on radon release from the site, topography and climate.²³⁸U and²²⁶Ra abnormities in stream sediments and soil were 40—90 cm deep and 790—800 m away downstream. Anomalies of radioactive contaminants of surface watercourses extended 7.5—13 km from the discharge of effluents of the site mainly depending on mechanical and chemical processes. There were about 2.86 ha rice fields and 1.59 km stream sediments contaminated. Erosion of tailings and mining debris with little or no containment or control accelerated the contamination processes.

     

Two new methods of determining radon diffusion in fish otoliths

Otoliths are bony structures found in the ears of fish and used in the²¹⁰Pb/²²⁶Ra dating method for age determination. This paper checks the assumption that²²²Rn is not lost from or added to orange roughy fish otoliths by diffusion, which would invalidate the technique. The first method of monitoring diffusion relies on measuring the gamma activity of daughter radionuclides. Otoliths were exposed to an atmosphere enriched in²²²Rn for 10 days, and the supported gamma activity inside them measured allowing for various decay corrections. The calculated radon addition was (0.5±0.5)% of the activity of the²²⁶Ra present. The second method used an alpha spectrometer and attempted to detect²²²Rn directly outgased from otoliths in the detector vacuum chamber. The results were consistent within errors with those of the first method and showed no loss or gain of²²²Rn, supporting previous estimates of a long life-span for the orange roughy. In contrast it was found that approximately 10% of²²²Rn formed in orange roughy fish scales was lost to an evacuated environment, (hence perhaps to an aqueous environment) and that for this species it could be difficult to base a dating method on analysis of scales. Nevertheless a preliminary minimum age of 57 years was obtained. The methods could be used with non-biological samples to determine²²²Rn diffusion rates.     

Radioactive contamination of the environment as a result of uranium production: a case study at the abandoned Lincang uranium mine,Yunnan Province,China

The distribution of radioactive pollutants, such as²²²Rn, U, Th and²²⁶Ra in the air, surface waters, soils and crops around the Lincang uranium mine, Yunnan Province, China, is studied. The mechanical, geochemical and biogeochemical processes responsible for the transport and fate of the radioactive elements are discussed based on the monitoring data. The pollutants concentrations of effluents from the mine tunnels were dependent on pH and which were controlled by biochemical oxidation of sulfide in the ore/host rocks. Radon anomalies in air reached 4 km from the tailings pile depending on radon release from the site, topography and climate.²³⁸U and²²⁶Ra abnormities in stream sediments and soil were 40—90 cm deep and 790—800 m away downstream. Anomalies of radioactive contaminants of surface watercourses extended 7.5—13 km from the discharge of effluents of the site mainly depending on mechanical and chemical processes. There were about 2.86 ha rice fields and 1.59 km stream sediments contaminated. Erosion of tailings and mining debris with little or no containment or control accelerated the contamination processes.     

Radioactivity measurements and radiation dose assessments due to natural radiation in Karabük (Turkey)

In this work, the radionuclide activity concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K in surface soils and radon levels in dwellings of Karabük, Turkey were determined in order to evaluate the environmental radioactivity. Concentrations of ²²⁶Ra, ²³²Th and ⁴⁰K radionuclides were determined using gamma spectrometry with using HPGe detector. The etch track detectors (CR-39) were used to determine the distribution of radon concentrations. The average activity concentrations for ²²⁶Ra, ²³²Th and ⁴⁰K were found as 21.0, 23.5 and 363.5 Bq kg⁻¹, respectively. The calculated average annual effective dose equivalent from the outdoor terrestrial gamma radiation from ²²⁶Ra, ²³²Th and ⁴⁰K is 53.5 μSv y⁻¹. The average radon concentration and annual effective dose equivalent of ²²²Rn in Karabük dwellings were obtained 131.6 Bqm⁻³ and 3.32 mSv y⁻¹, respectively. The evaluated data were compared with the data obtained from different countries.     

Radionuclide and chemical hazards of a radium ore revigator

A study to characterize the radionuclide and chemical components in a radium-ore revigator has been completed. Measured activities of dissolved ²²²Rn, ²²⁶Ra, and U isotopes, determined in the water using radioanalytical techniques, exceeded recommended limits in drinking-water supplies. Trace-metal concentrations, determined using inductively coupled plasma mass spectrometry, increased in the water with exposure time and exceeded recommended drinking-water limits for V and As. The contribution to, and dose from, the airborne radon-gas level in a room due to radon emanation from a revigator were evaluated. The annual committed effective dose resulting from consuming the radionuclides in the revigator water were estimated to be ~100 μSv/y for combined uranium and radium.     

Study of the Energy Resolution in Alpha-Particle Spectra from Electrodeposited Radium Sources

Electrodeposited ²²⁶Ra sources were prepared and measured in order to perform a detailed study of the energy resolutions attained with two recent electrodeposition procedures for preparing spectrometric radium sources. The values of the energy resolution for the high-energy emission of ²²⁶Ra and for the single-emissions of ²¹⁰Poand ²²²Rn were calculated by fitting the data with a curve formed by the convolution of two left-handed exponentials with a Gaussian function. Significant differences between the energy resolutions for the aforementioned radionuclides were observed. The ²¹⁰Po energy resolutions were, in general, somewhat better than those obtained for ²²⁶Ra. On the contrary, the energy resolutions found for ²²²Rn were notably poorer than those obtained for ²²⁶Ra and ²¹⁰Po. These discrepancies can be satisfactorily explained by taking into consideration the distribution of these nuclides in the sources and the effect of radon diffusion involved in this type of thin deposit.     

Natural radioactivity in Algerian bottled mineral waters

The activity concentrations of some radionuclides in Algerian bottled mineral waters were determined using CR-39 nuclear track detectors for ²²²Rn, and a high resolution gamma-ray spectrometry for ²²⁶Ra, ²³²Th and ⁴⁰K. The mean specific activities of ²²²Rn , ²²⁶Ra, ²³¹Th and ⁴⁰K in the drinking mineral waters were 7±4 Bq^.l^-1, 26±11 mBq^.l^-1, 30±13 mBq^.l^-1 and 1±0.5 Bq^.l^-1, respectively. These values are comparable with concentrations reported for other countries. The effective doses due to intake of these radionuclides as a consequence of direct consumption of drinking mineral waters have been determined. The estimated effective doses were 56.8 mSv^.y^-1 for ²²²Rn, 3.94 mSv^.y^-1 for ²²⁶Ra, 4.45 mSv^.y^-1 for ²³²Th and 3.33 mSv^.y^-1 for ⁴⁰K. Contribution of these radionuclides to the effective dose due to ingestion and inhalation of all terrestrial radionuclides is estimated to be only 0.012%.     

Solvent extraction of uranium(VI) with benzyloctadecyldimethylammonium chloride (BODMAC) from highly concentrated chloride solution

The ²²²Rn emanation fraction (EF) released from the technically enhanced naturally occurring radioactive material (TE-NORM) wastes at certain sites of petroleum and gas production was determined. The samples were analyzed by γ-ray spectrometry to determine the activity concentration of the ²²⁶Ra content, of which the ²²²Rn emanation fraction was calculated. The results showed that the ²²²Rn emanation fraction differs in the oil and gas production sites and it is independent of the activity concentration of ²²⁶Ra. This revised version was published online in August 2006 with corrections to the Cover Date.     

222Rn behavior at the Latera geothermal field (Northern Latium,Italy)

Permanent probes to sample soil gases were placed at the Latera geothermal field, located in the Volsini Mts., Latium, Italy. Due to high uranium concentrations in the area's alkali-potassic volcanics outcropping, quite high²²²Rn values, ranging from 9,260 up to 753,000 Bq/m³, were found. The highest radon activities match tectonic structures such as fractures and faults, and a deep high structure which constitutes the geothermal reservoir. These high radon values also conform to a major amount of⁴He and CO₂. The latter gases are enriched in the gaseous phase of the geothermal fluids, and their migration is also controlled by structural features. This suggests that the enrichment of²²²Rn in the soil gases, can be linked to a direct contribution of²²⁶Ra, carried by deep-seated fluids from the reservoir itself.     

Activity concentrations of 226Ra, 228Ra, 222Rn and their health impact in the groundwater of Jordan

The activity concentrations of ²²⁶Ra, ²²⁸Ra and ²²²Rn were measured in 87 groundwater samples to estimate the activity concentrations of these radionuclides and health impact due to intake of these radionuclides in groundwater of Jordan. The mean activity concentrations of ²²⁶Ra, ²²⁸Ra and ²²²Rn in groundwater were found to be 0.293?±?0.005 Bq L^?1, 0.508?±?0.009 Bq L^?1 and 58.829?±?8.824 Bq L^?1, respectively. They give a mean annual effective dose of 0.481 mSv with mean lifetime risk of 24.599?×?10^?4, exceeding the admissible limit of 10^?4. Most of the received annual effective dose (59.15% of the total) is attributed to ²²⁸Ra.

     

Assessment of inhalation exposure potential of broken uranium ore piles in low-grade uranium mine

This paper presents the assessment of inhalation exposure potential of broken uranium ore piles in different stopes of Jaduguda uranium mines of India. ²²²Rn emanation coefficient of broken uranium ore was measured in laboratory by collecting air sample from airtight glass jar containing ore sample. An attempt was also made to correlate the emanation coefficient with ²²⁶Ra content of the ore. The ²²²Rn progeny doses estimated based on radon activity concentration of broken ore, occupancy period and equilibrium ratio in different stopes were well below the prescribed limit of International Commission on Radiological Protection. The maximum ²²²Rn progeny dose contribution from broken ore piles was worked out to be 0.22 mSv year^?1. This suggests that the broken ore piles are not the significant contributor of inhalation exposure under the existing ventilation condition of Jaduguda uranium mine.