222Rn content and234U/238U activity ratio in groundwaters

Geochemical radioanalytical studies of groundwater were performed in the valleys of Villa de Reyes and San Luis Potosi (Mexico). The experiments were designed to measure radon and uranium content and²³⁴U/²³⁸U activity ratio in groundwater samples taken from wells in these sites and at the Nuclear Center of Salazar, Mexico.²²²Rn content varied depending on the sample source, reaching a maximum value of 235 pCi/l; uranium concentration results were less than 1 g/1 and²³⁴U/²³⁸U activity ratios were close to equilibrium.     

222Rn radioactivity in urban waters of fault zone in China: dose rate and risk assessment

Journal of Radioanalytical and Nuclear Chemistry - The exhalation of radon from waters surrounding active fault zones is at present not well understood. In this work, radon concentrations in urban...     

A survey of 222Rn concentrations in dwellings of Turkey

As part of a national program to determine public exposure to natural radiation, indoor air ²²²Rn concentrations were determined in dwellings of Turkey. The ²²²Rn concentrations were measured with time-integrating passive nuclear etched track detectors in 27 provincial centers. The indoor radon concentrations were found to be in the range of 10-380 Bq^.m^-3. This revised version was published online in August 2006 with corrections to the Cover Date.     

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.     

Determination of 222Rn in Iranian mineral waters using liquid scintillation alpha-spectrometry

Liquid scintillation counting (LSC) method has been used for the measurement of ²²²Rn in mineral water samples under a pilot project for the first surveillance in Iran. Low level background LSC counter Quantulus and pulse-shape analysis method have been employed. The concentration of ²²²Rn found in mineral waters of the studied areas ranges from about 1 to 75 Bq/l. The best lower limit of detection obtained with the applied technique was 0.069 Bq/l for a counting time in the range of 236–296 minutes.     

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.     

Effect of the natural radioactivity concentrations and 226Ra/238U disequilibrium on cancer diseases in Penang,Malaysia

Natural radioactivity measurements and assessment of radiological hazards in soil and sand samples obtained from Penang, Malaysia were carried out using the Exploranium GR-135 Plus “Identifier” Radioisotope Identification Device and high-resolution High Purity Germanium (HPGe) detector system. The activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 184±11, 396±22, 165±14, and 835±28 Bq kg^?1 respectively, and the external gamma dose rate is 315±44 nGy h^?1 for soil samples. For sand samples, the activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 31±8, 62±16, 36±6, and 369±17 Bq kg^?1, respectively, and the external gamma dose rate is 66±12 nGy h^?1. To assess the radiological hazard of radioactivity present in the samples, the radium equivalent activity, annual effective dose, annual gonadal dose equivalent, external hazard, and internal indices were calculated.The Ra_eq values of soil samples were higher than the limit of 370 Bq kg^?1, which is equivalent to a gamma dose of 1.5 mSv yr^?1, whereas the Ra_eq for sand samples was lower than 370 Bq kg^?1. The calculated concentrations by HPGe spectroscopy were compared with the measured concentrations detected by a GR-135 spectrometer. The calculated and measured gamma dose rates had an ideal correlation coefficient R of 0.72. The gamma dose rates in Penang increased with the average annual age-standardized rates (ASR) for all cancers between 1994 and 2010. The effects of the pH value of soil and sand samples on natural radionuclides concentrations were investigated. The high concentration of ²²⁶Ra/²³⁸U ratio disequilibrium (²²⁶Ra/²³⁸U of 1.76–2.33) was observed in the sampling sites. Moreover, a portable continuous radon monitor (SNC, model 1029, Sun Nuclear Corporation) was used to measure the radon concentration of the soil surface. The radon concentrations were found to vary from 7 to 50 Bq m^?3. A positive correlation was observed between the radon and radium concentrations in samples measured by the SNC continuous radon monitor and HPGe detector.     

238U, 234U and 226Ra concentrations in mineral waters and their contribution to the annual committed effective dose in Turkey

Activity concentrations of ²³⁴U, ²³⁸U and ²²⁶Ra in mineral waters were determined on the basis of nine water bottling facilities using alpha particle spectrometry. The mineral water samples were collected from three geographic regions of Turkey. The radiochemical separation used in the uranium analysis is based on the isolation of uranium radioisotopes from other radionuclides such as Th, Am, Pu and Np using UTEVA resin. Alpha sources were prepared using electrodeposition method. The activity concentration of ²²⁶Ra was determined after deposition on a membrane using BaSO₄ co-precipitation method. The activity concentrations (mBq L^?1) of ²²⁶Ra, ²³⁸U and ²³⁴U ranged from <0.56 to 165, from <0.42 to 439 and from <0.42 to 464, respectively. The measured activity concentrations were used for the calculation of the average total annual effective ingestion doses for children and adults. The committed effective doses were calculated for three different scenarios according to mineral water consumption rate. In the most extreme scenario (for age group 12–17), all water samples except MW1 and MW2 cause annual committed effective doses below the reference level (0.1 mSv year^?1) recommended by World Health Organization (WHO).     

238U and 232 Th concentrations in various potable waters in Morocco and resulting annual equivalent doses for the population

Summary The ²³⁸U and ²³² Th concentrations were measured in various potable water samples collected from various cities in Morocco using CR-39 and LR-115 type II solid state nuclear track detectors (SSNTDs). The measured ²³⁸U and ²³² Th concentrations ranged from 0.37±0.02 to 13.60±0.97 mBq ^. l^-1 and 0.33±0.02 to 7.10±0.49 mBq ^. l^-1, respectively. Alpha-activities due to annual ²³⁸U and ²³² Th intakes were assessed in various compartments of the human body of adult members of the Moroccan population using ICRP biokinetic models. The equivalent doses due to annual intakes of ²³⁸U and ²³² Th were evaluated. The influence of the target tissue mass and the activities of ²³⁸U and ²³² Th on the annual committed equivalent doses in the compartments of the human body was investigated.     

The concentration of <Superscript>238</Superscript>U and the levels of gross radioactivity in surface waters of the Van Lake (Turkey)

Gross α and gross β activities and ²³⁸U concentrations were determined in 18 surface water samples collected from Van Lake. The instrumentations used to count the gross α and gross β activities and to determine the ²³⁸U concentrations were α/β counter of the multi-detector low background system (PIC-MPC-9604) and Inductively Coupled Plasma-Mass Spectrometry (Thermo Scientific Element 2), respectively. Concentrations ranging from 0.001 to 0.021 Bq L⁻¹ and from 0.111 to 2.794 Bq L⁻¹ were observed for the gross α and β activities in surface waters, respectively. For all samples the gross β activities were higher than the corresponding gross α activities. The results indicated that the gross α radioactive contamination in water samples was lower than recommended values for the guideline of drinking waters and most of the gross β activities in water samples were higher than those in the same procedure. The ²³⁸U concentrations ranged from 74.49 to 113.2 μg L⁻¹ in surface waters. The obtained results have showed that ²³⁸U concentrations are higher than guideline values for uranium.     

Local variations of atmospheric 222Rn and 210Pb concentrations in Badgastein (Austria)

²²²Rn was measured and aerosols for ²¹⁰Pb determination were collected simultaneously outdoors at ground level near the train station of Badgastein (1080 m a.s.l.), and later on also on the nearby Stubnerkogel (2230 m a.s.l.). Radon concentrations at lower altitude were up to 140 Bq/m³, on the mountain the usual background levels were found. In contrary to the differing radon levels, the ²¹⁰Pb activity concentrations were in the same order of magnitude for both locations with values between 0.16 and 0.77 mBq/m³.     

Activity concentrations of238U and226Ra in agricultural samples

Distributions of²³⁸U and²²⁶Ra in agricultural samples and cultivated soils have been studied over ten years. The crops are rice, spinach and Chinese cabbage. Two investigated areas have been selected (35° 18 N, 113° 35 E). The agricultural samples and soils were collected annually from May 1982 through October 1991. The activity concentrations of²²⁶Ra in agricultural samples are greater than those of²³⁸U. The transfer factors of²³⁸U,²²⁶Ra are from 0.06·10^–3 to 1.2·10^–3. The²²⁶Ra/²³⁸U ratios for three agricultural samples have their characteristic values.     

Concentration of 238U and 232Th among constituent minerals of two igneous plutonic rocks exhibiting elevated natural radioactivity levels

The concentrations of ²³⁸U and ²³²Th of the constituent minerals in two plutonic rock samples, from N. Greece, exhibiting elevated levels of bulk rock natural radioactivity were determined by using LA-ICP-MS. The available data of whole rock ²³⁸U and ²³²Th concentrations were also used. The minerals were separated using a combination of heavy liquids of various densities, shaking table and magnetic separation techniques. The great variation in the concentrations of ²³⁸U and ²³²Th is probably indicative of the different distribution of U and Th within the same rock, as well as to secondary post-magmatic processes that were responsible for the redistribution of U and Th. An estimation of the contribution of each mineral constituent to the natural radioactivity levels of the bulk rock is attempted. Thorite and zircon contribute the most to the whole rock ²³⁸U and ²³²Th content, while the contribution of apatite is moderate. The contribution of the rest of the minerals examined (fluorite, quartz, plagioclase, K-feldspar, amphibole, pyroxene, magnetite and biotite) is not important.     

Anomalously high 234U/238U activity ratios of Tatsunokuchi hot spring waters, Ishikawa Prefecture, Japan

Uranium concentration and the ²³⁴U/²³⁸U activity ratio have been measured for the Tatsunokuchi hot spring waters of Ishikawa Prefecture in Japan, collected periodically over a long period (1977-2000). The concentration of ²³⁸U varied drastically between 0.045 and 1.02 mBq/l (a factor of about 20), while the ²³⁴U concentration was almost unchanged, ranging from 2.30 to 3.07 mBq/l. Resultant ²³⁴U/²³⁸U activity ratios showed a wide range from 2.7 to 51. Equilibrium calculation by using the geochemical code showed that U for one end-member representing low uranium contents and very high ²³⁴U/²³⁸U ratios was expected to exist as UO₂(CO₃)₂ ^2-. By using the U isotopic and ¹⁴C dating methods, the age of this water was roughly estimated to be in the range of 10⁴-10⁵ years.     

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.     

Annual effective dose due to 222Rn and evaluation of 238U, 232Th and 40K contents in soil at the south-eastern coastal area of Bangladesh

Journal of Radioanalytical and Nuclear Chemistry - On-site 222Rn concentration at three different soil depths was measured at the south-eastern coastal area of Bangladesh to evaluate the annual...     

Natural radioactivity levels in mineral,therapeutic and spring waters in Tunisia

Radioactivity measurements were carried out in 26 groundwater samples from Tunisia. Activity concentrations of uranium were studied by radiochemical separation procedures followed by alpha spectrometry and that for radium isotopes by gamma-ray spectrometry.The results show that, the concentrations in water samples range from 1.2 to 69 mBq/L.1, 1.3 to 153.4 mBq/L, 2.0 to 1630.0 mBq/L and 2.0 to 1032.0 mBq/L for ²³⁸U, ²³⁴U, ²²⁶Ra and ²²⁸Ra, respectively. The U and Ra activity concentrations are low and similar to those published for other regions in the world. The natural radioactivity levels in the investigated samples are generally increased from mineral waters through therapeutic to the spring waters.The results show that a correlation between total dissolved solids (TDS) values and the ²²⁶Ra concentrations was found to be high indicating that ²⁶⁶Ra has a high affinity towards the majority of mineral elements dissolved in these waters. High correlation coefficients were also observed between ²²⁶Ra content and chloride ions for Cl^?–Na⁺ water types. This can be explained by the fact that radium forms a complex with chloride and in this form is more soluble.The isotopic ratio of ²³⁴U/²³⁸U and ²²⁶Ra/²³⁴U varies in the range from 0.8 to 2.6 and 0.6 to 360.8, respectively, in all investigated waters, which means that there is no radioactive equilibrium between the two members of the ²³⁸U series. The fractionation of isotopes of a given element may occur because of preferential leaching of one, or by the direct action of recoil during radioactive decay.The annual effective doses due to ingestion of the mineral waters have been estimated to be well below the 0.1 mSv/y reference dose level.     

Measurements of222Rn migration in soil

The concentration of radon (²²²Rn) was measured in the soil near the ground surface, using CR/39 solid state nuclear track detectors. The measurements were carried out in PVC tubes at 0.25 m intervals up to 1.25 m. The detectors were etched in 7N NaOH solutions at 80°C. The -tracks from radon's decay were counted using a microscope. A microscope-camera-computer system developed for automatic counting was also used. The results provide evidence for the non-diffusive transport of radon in soils. A transport length of (46.9±3.2) cm was estimated for radon transport near ground surface. Also the variation of soil's radon concentration was correlate to humidity and atmospheric pressure.     

Optimisation of enrichment methods and evaluation of errors for high sensitivity measurement of 222Rn in natural waters

Journal of Radioanalytical and Nuclear Chemistry - A method was applied in the separation and determination of trace lithium in uranium products. Separation and enrichment of lithium was carried...     

Influence of the precipitation rate on the seasonal variation in the specific radioactivity of short-lived222Rn daughters in precipitation

Data of variations in the RaB/²¹⁴Pb/ and RaC/²¹⁴Bi/activities in precipitation obtained from observations made for a period of almost 5 years are given together with data on changes in precipitation rate measured simultaneously. It is concluded from analysis of these data that the precipitation rate variation contributes to approximately 40% to the seasonal variation in the specific activity of precipitation.