222Rn and 226Ra activity concentrations in groundwaters of southern Poland: new data and selected genetic relations

Since 2008, the authors have been conducting research into ²²²Rn and ²²⁶Ra activity concentrations in shallow circulation groundwaters in southern Poland. Measurements have been performed with a liquid-scintillation method and ultra low-level liquid-scintillation spectrometers α/β Quantulus 1220. The research carried out so far has demonstrated that in the Sudetes groundwaters with high activity concentrations of ²²²Rn and ²²⁶Ra are common. In other studied areas in southern Poland no shallow circulation groundwaters with high radon or radium concentrations have been found yet. The conducted research has demonstrated that the activity concentration of ²²²Rn dissolved in shallow circulation groundwaters in the Sudetes depends chiefly on the amount of radon, which after being released as gas from reservoir rocks is dissolved in waters flowing through these rocks. At the same time, the concentration of ²²²Rn dissolved in some shallow circulation groundwaters in the Carpathians is influenced significantly by the amount of radon produced from the decay of its parent ion ²²⁶Ra²⁺ dissolved in these waters.     

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.     

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.     

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.     

Natural radioactivity of geothermal water in Beijing,China

In this work, we collected 101 geothermal water samples to investigate comprehensively the radioactivity of geothermal water in Beijing. The concentrations of gross beta, ²²⁶Ra and ²²²Rn were measured and the obtained values were in the range of 0.032–7.060, 0.023–0.363 and 0.470–29.700 Bq/L, respectively. The samples with higher concentration of ²²²Rn were found to be located near large faults. The effective dose of ²²²Rn in the air for three cases were calculated to be greater than radiation dose limit of 1 mSv/a.     

Application of the relative uranium-series disequilibrium in soil to locate and/or confirm precisely active fault traces: A new technique

Fault traces have been previously located from measurements of ²²²Rn in soils taken a constant soil-depth across the fault trace. In this paper, we have studied the uranium-series disequilibria of the ²²⁶Ra, ²²²Rn (gas) and ²¹⁴Bi radionuclides, not only for their horizontal spatial patterns across the fault trace, but also for their vertical spatial patterns near and at the fault trace itself. Radon-222 activities in the soil-gas were measured on-site with a radiation monitor and a Lucas cell. Radium-226 and ²¹⁴Bi were determined in soil samples in the laboratory by gamma-ray spectroscopy. A new technique employing the measurement of ²²²Rn versus soil-depth shows a decrease in ²²²Rn activity at the fault trace due to the much higher soil-gas permeability as a result of the fractured soil, as well as relative larger uranium-series disequilibria, in respect to an increase in ²²²Rn activity at normal sites, where the soil is not fractured. Finally, it is suggested that fault trace detection could possibly also be performed by measuring ²¹⁴Bi in surface soils (0-100 cm) along a transect.     

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.     

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.     

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.     

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.     

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.     

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.     

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%.     

Direct determination of 226Ra in NORM/TENORM matrices by gamma-spectrometry

Summary The main shortcoming with the procedure to determine ²²⁶Ra in a gamma spectrum of an environmental sample by means of the ²¹⁴Bi and ²¹⁴Pb photopeaks is the likelihood of ²²²Rn leakage from the sample counting vial. An option to make such determination is to disregard the ²²⁶Ra gamma-contributions to the spectrum, other than 186.2 keV (3.5%), subtracting the ²³⁵U contribution to the ²²⁶Ra+²³⁵U peak at 186 keV. The use of this option to determine directly ²²⁶Ra activity concentrations in environmental samples and in NORM/TENORM matrices will be presented and discussed.     

Radiological characterization of drinking waters in Central Italy

Due to the importance of water in human life, its quality must be strictly controlled; for this purpose, simple and reliable analytical methods must be available. In this study, a monitoring of radioactivity content was performed in tap waters collected in a region of Central Italy to check the compliance with recent European and Italian regulations. Gross alpha and beta activities, ²³⁸U, ²³⁴U, ²²⁶Ra, ²²²Rn, and ³H concentrations were measured. Gross alpha and beta activities were determined by standard ISO 9696 and ISO 9697; for ²²⁶Ra, ²²²Rn and ³H determination, liquid scintillation was used. ²³⁸U and ²³⁴U concentrations were determined by alpha spectrometry after separation from the matrix by extraction chromatography and electroplating. The results revealed that the tritium concentration was always lower than 6.75 Bq l^− 1. The concentrations (mBq l^− 1) of ²²⁶Ra, ²²²Rn, ²³⁸U, and ²³⁴U ranged from < 1.70 to 15.31, from 0.69 to 20.3, from 0.65 to 48.77, and from 0.78 to 51.50, respectively.²³⁴U/²³⁸U ratios were higher than 1 in most cases. The results obtained revealed that, in most samples, gross alpha and gross beta were lower than the parameter value indicated in the international regulations. An attempt was also made to find a correlation between these results and the chemical parameters of waters.     

A simple technique for surface labeling of solids with222Rn and its short-lived decay products

A simple radioactive labeling technique is described which is based on a recoil injection of atoms of²²²Rn and its decay products from a²²⁶Ra source into thin surface layers of solids.     

Radionuclides analysis in hot spring waters in Korea by liquid scintillation counting

Tritium and ¹⁴C concentration in hot spring water in Korea were determined. Tritium in the most hot spring samples could not detected and concentration range was <0.5?C1.31?TU. And ¹⁴C contents were ranged 1.7?C78.6?pMC. From the ³H and ¹⁴C analysis, we found some hot springs are mixed with recent groundwater and hot spring water ages were estimated from 1,940 to 32,800?years. And also, ²²⁶Ra and ²²⁸Ra were determined simultaneously in hot spring water, and some other radionuclides were also analyzed. Content distribution of ²²²Rn was 50?C3,760?pCi/L, ²²⁶Ra was <0.003?C0.15?Bq/L and ²²⁸Ra was below the detection limit.     

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.     

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.

     

Concentration of radionuclides in building and ceramic materials of Bangladesh and evaluation of radiation hazard

The concentration of radioactive²²⁶Ra,²³²Th and⁴⁰K in building and ceramic materials of Bangladesh was investigated by γ-spectrometry with two HPGe detectors. Radium equivalent activities, representative level index values, criterion formula, emanation coefficients and²²²Rn mass exhalation rates were estimated for the radiation hazard of the natural radioactivity in the materials. The activity concentrations of the natural radionuclides, radium equivalent activities, emanation coefficients and²²²Rn mass exhalation rates are compared with the corresponding values for building and ceramic materials of different countries. The radium equivalent activities in the samples varied between 30.9 (mosaic stone) and 328.0 Bq·kg⁻¹ (gypsum). The emanation coefficient of the materials ranged from 7.83 (cement) to 33.0% (soil) and the²²²Rn mass exhalation rate ranged from 2.31 (stone chips) to 118.0 μBq·kg⁻¹·s⁻¹ (gypsum).