The paper describes a method of determination of Ra-226 in natural water using ICP-QQQ-MS, Agilent 8900, that enables an efficient direct determination of Ra-226 with high sensitivity without using any reaction gas and separation procedures for interference removal. The matrix effect, together with the instability of the sensitivity are controlled by spiking the sample with Ra-226. The method is simple and fast with a detection limit around of 0.1 fg g-1 (3.6 mBq kg-1), which is tenfold lower than required by the EU Directive for water consumption (40 mBq kg-1) and five times better than results obtained from alternative direct method for routine analysis described in the literature. The method can easily be implemented for routine analysis Ra-226 which was demonstrated by direct determination of Ra-226 in IAEA proficiency test water sample. This is the first time that the accuracy (trueness and precision) of a mass spectrometry method for the direct determination of Ra-226 has been tested and confirmed in an independent proficiency test.

The Fukushima Daiichi Nuclear Power Station (FDNPS) accident caused a significant deposition of 137Cs onto the soil surface. In the present study, the depth profile of a soil sample was collected to check the migration of 137Cs contamination. 137Cs activity concentration was measured with a high purity germanium detector (HPGe). The activity concentrations of 137Cs in the 0–2 cm layer was 250 ± 1 kBq/kg whereas the 10–15 cm depth was 0.5 ± 0.01 kBq/kg. Rare earth elements (REEs), uranium (U), and thorium (Th) were measured in the same samples using inductively coupled plasma-mass spectrometry (ICP-MS).

The pure beta emitter Sr-90 (T-1/2 = 28.8 y) is a typical contaminant released by nuclear accidents and nuclear explosions. In the event of a nuclear disaster, it is crucial to identify radioactive pollutants quickly, to expedite the public's awareness of radiation exposure. In this work, a rapid Sr-90 analysis protocol using thermal ionization mass spectrometry (TIMS) was developed for milk samples. With the improved sample preparation, Sr separation, and a newly developed TIMS method, 18 milk samples can be analyzed in less than 30 h and only 1 mL of cow milk is required for the complete analysis. The minimum detectable activity concentration of Sr-90 is affected by the stable Sr concentration therefore, it is around 500 mBqkg(-1) (similar to 100 agg(-1)). Additionally, Sr-87/Sr-86 isotope ratios (0.71518(9)-0.74132(4)) were determined for the first time in Japanese cow milk samples.

Sr-90 and Cs-137 activity concentrations were determined by radiometric methods in 76 soil samples (soil, litter, rain gutter deposit, and roadside sediment samples) affected by the Fukushima Dai-ichi Nuclear Power Station (FDNPS) accident and collected from the Fukushima exclusion zone. The Sr-90 and Cs-137 activity concentrations were in the range of 3 to 1050 Bq kg(-1) (median 82 Bq center dot kg(-1)) and 0.7 to 6770 kBq center dot kg(-1) (median 890 kBq center dot kg(-1)), respectively (decay correction date: March 15, 2011). A strong positive correlation was found between Sr-90 and Cs-137 activity concentration and higher mobility of Sr-90 was confirmed in Japanese soil samples. The activity ratio of Sr-90/Cs-137 in 85% of all samples was in the range of 5.0 x 10(-5) to 5.0 x 10(-4) with a median of 1.2 x 10(-4). From the activity ratio values it was concluded that the Sr-90 released to the atmosphere was only around 0.0003 0.02 PBq which is negligible compared to the Chernobyl accident (similar to 10 PBq) or other nuclear accident contaminations. From the standpoints of radioecology and radiation safety, Cs-137 remains the primary pollutant of the FDNPS accident.

In-situ measurements by gamma-ray spectrometry using a NaI(Tl) scintillation spectrometer are performed to discriminate primordial and artificial radionuclides contributing to ambient gamma dose rates in the living environment to quantify prolonged influence of nuclear accidents. However, low energy resolution of the spectrometer causes poor discrimination in the measurements at high-dose-rate points, which leads to overestimation of ambient gamma dose rate from the primordial radionuclides. The present study clarified that photon fluxes originating from 40K and 214Bi were affected by the presence of 134Cs, whereas those from 208Tl were independent of it. In addition, the absorbed dose rates in air were strongly correlated with the 208Tl photon fluxes. These findings indicate that 208Tl photon fluxes can be used to evaluate absorbed dose rates in air from the primordial radionuclides. When estimated from the 208Tl photon fluxes only, the absorbed dose rates in air in Namie Town and Okuma Town, locations affected by the Fukushima Dai-ichi Nuclear Power Plant accident, were 19-71 and 20-47 nGy h-1, respectively.

Various radionuclides including fission products and heavy nuclides were released into the environment during the Fukushima Daiichi Nuclear Power Station (FDNPS) accident. The dissolution followed by migration of deposited radionuclides of Cs, Sr and U on soils could take place to the local environment. Therefore, it is necessary to determine sorption-desorption coefficients of U in soil-water system around the FDNPS from a migration viewpoint. The determination of sorption coefficient Kd(S) as well as desorption coefficient Kd(D) for U has been carried out in the present study using a laboratory batch method. Stable U was used for sorption from simulated ground water onto contaminated soil samples collected from Okuma Town, Fukushima. Different soil parameters were measured to understand their effects on sorption and desorption processes. The obtained Kd(S) and Kd(D) values of U were compared with values of Kd(S) and Kd(D) of Cs and Sr and Kd(S)-U in known Fukushima accident contaminated soils reported in the literature for better understanding. It was observed that Kd(S)-U varied from 160 to 5100 L/kg, whereas Kd(D)-U ranged from 200 to 11000 L/kg. Kd(D) was higher than Kd(S) for U in these soils implying irreversibility of the sorption process. Pearson's correlation of Kd(S) values suggested that U sorption is affected by various soil parameters. However, desorption is decided by the nature of U species formed in sorption process and soil parameters like pH, presence of carbonates, Ca ions, clay minerals etc. to some extent. The comparison between Kd(S) and Kd(D) values for Cs, Sr and U revealed that unsorbed Sr could migrate farther than unsorbed Cs or U under the present experimental conditions. Both sorption and desorption studies are of great importance to understand migration of metal ions from contaminated sites to local uncontaminated areas.

Radon passive monitors based on solid state nuclear track detectors (SSNTD), especially CR-39, are widely used in radon and thoron studies. They may be subjected to the influence of external factors, like changing of temperature, humidity, and pressure, both before and during the measurement. Evaluation of the exposed detectors involves chemical processing, whose conditions also influence the measurement results. The aim of this study was to check several factors, as to whether they may modify the response of CR-39 detector: concerning the phase before evaluation, storage time, and temperature during storage; and concerning the evaluation procedure, etching time, and pre-etching treatment using hot water and carbon dioxide atmosphere. Two experiments were conducted by irradiation of CR-39 detectors using alpha particles emitted from a mono-energetic 241Am source and exposed in radon atmosphere. Track density dependence of the age of production was found to be statistically not significant. On the other hand, pre-etching treatment using hot water and carbon dioxide with different etching times showed statistically significant effects on track area, track sensitivity, and roundness. It was concluded that there are simple methods to increase performance of nuclear track detectors, and that storage time is not a factor of concern.

Radiostrontium (r-Sr: 90Sr) is one of the primary fission products in nuclear power plants and generates liquid radioactive waste when intermixed to the aqueous matrix. Therefore, separation or preconcentration of r-Sr from the aqueous matrices is necessary for environmental monitoring or nuclear forensics. The solid-phase extraction (SPE) approach is prevalently used for r-Sr isolation and to design matrix-specific methods, while generalized SPE-assisted operating protocols are not proposed by far. In the current work, four different SPEs, namely AnaLig Sr-01, Eichrom Sr, Triskem TK100, and Eichrom DGA, were evaluated for selective separation of Sr from aqueous matrices. Operating variables, e.g., solution acidity, washing solvent, eluent-type or volume, loading or elution flow-rate, were varied to optimize the SPEs performance. The objective was to ascertain the operating variables for maximum Sr-separation yield from aqueous environmental samples with the SPEs mentioned above. In addition, the Sr-separation efficiency of SPEs was evaluated by calculating the separation factor (SFSr/M) between Sr and interfering elements to r-Sr (M = Ca, Mg, Ba, or Y), and the Sr-retention capacity of the SPEs was determined. Finally, the optimized operating variables for the evaluated SPEs were used to construct protocols for r-Sr separation from aqueous matrices. Real 90Sr contaminated aqueous samples from the Chernobyl nuclear power plant cooling pond were treated by those protocols, and the results are validated comparing with the IAEA-recommended classical protocol. All the SPEs were able to isolate Sr at varying extents from matrices at the optimum conditions, even at much higher contents of interfering elements. Eichrom Sr or AnaLig Sr-01 showed better Sr-retention capability among the SPEs, while Triskem TK100 showed superiority over other SPEs regarding Sr-selectivity.

The Kanyakumari coastal area in the southernmost part of Tamil Nadu, India is a well-known natural high background radiation area due to the abundance of monazite in beach placer deposits. In the present study, the concentrations of major oxides, rare earth elements (REEs), Th and U were measured to understand geochemical characteristics of these monazite sands. Based on the ambient dose rate, 23 locations covering an area of about 60 km along the coast were selected for sample collection. The concentrations of U and Th ranged from 1.1 to 737.8 ?g g-1 and 25.2?12250.6 ?g g- 1, respectively. The Th/U ratio ranged from 2.2 to 61.6, which clearly indicated that Th was the dominant contributing radionuclide to the enhanced natural radioactivity in this coastal region. The chondrite-normalized REEs pattern of the placer deposits showed enrichment in light REEs and depletion in heavy REEs with a negative Eu anomaly that indicated the monazite sands were derived from granite, charnockite, and granitoid rocks from the Nagercoil and the Trivandrum Blocks of the Southern Granulite Terrain.

In this paper, DGA-normal resin has been used for the chemical separation of Sr and Y from Cs as well as other elements in standard solutions. The decontamination factor of Cs was tested in different acidic media. It was found that 8 M HNO 3 was the most effective rinsing solution with a Cs decontamination factor exceeding 400,000. Application of the DGA-normal resin allows the separation of Y and Sr from other interfering beta emitter isotopes. This resin is suitable for 90 Sr and 90 Y separation in contaminated Fukushima soil samples giving the prospect of 90 Sr measurement in a direct ( 90 Sr) and indirect way ( 90 Y).

In the present study, Cs-137 and U-238 activity concentrations, U-234/U-238 activity ratio, and U-235/U-238 isotope ratio were measured in fifteen soil samples collected from the exclusion zone around the Fukushima Daiichi Nuclear Power Station (FDNPS). The Cs-137 activity concentrations of Fukushima-accident contaminated soil samples ranged from 29.9 to 4780 kBq kg(-1) with a mean of 2007 kBq kg(-1). On the other hand, the U-238 activity concentrations of these soil samples ranged from 5.2 to 22.4 Bq kg(-1) with a mean of 13.2 Bq kg(-1). The activity ratios of U-234/U-238 ranged from 0.973 to 1.023. The U-235/U-238 isotope ratios of these exclusion zone soil samples varied from 0.007246 to 0.007260, and they were similar to the natural terrestrial ratio confirming the natural origin. Using isotope dilution technique, the U-235/Cs-137 activity ratio was theoretically estimated for highly Cs-137 contaminated soil samples from Fukushima exclusion zone ranged from 5.01 x 10(-8) - 6.16 x 10(-7) with a mean value of 2.51 x 10(-7).

There has been tritium groundwater leakage to the land side of Fukushima Dai-ichi nuclear power plants since 2013. Groundwater was continuously collected from the end of 2013 to 2019, with an average tritium concentration of approximately 20 Bq/L. Based on tritium data published by Tokyo Electric Power Company Holdings (TEPCO) (17,000 points), the postulated source of the leakage was (1) leaks from a contaminated water tank that occurred from 2013 to 2014, or (2) a leak of tritium that had spread widely over an impermeable layer under the site. Based on our results, sea side and land side tritium leakage monitoring systems should be strengthened.

In recent years, owing to significant developments on sample introduction, detector and interference removal techniques, many successful Sr-90 measurments have been reported using mass spectrometry instruments.For this purpose, inductively coupled plasma mass spectrometry (ICP-MS) instruments with collision/reaction cells or triple quadrupole system have been primarily applied.Alternatively, thermal ionisation mass spectrometry (TIMS) is a robust technique for Sr-90 determination.The main advantages of the mass spectrometry method over the radiometric are the shorter analysis time, higher sample throughput and less sample intake.The low level Sr-90 detection in environmental samples with mass spectrometry instrument is a challenging task.The first critical point is the isobaric interference of Zr-90 as a consequence of significant amounts of Zr in the environment.The second critical point for the application of mass spectrometry instruments for Sr-90 determination is the peak tailing on the higher mass side from Sr-88.Considering the need of rapid and precise Sr-90 determination aſter the Fukushima nuclear accident, a Sr-90 analysis method was developed using the Phoenix X62 TIMS in the laboratory of the National Institutes for Quantum and Radiological Science and Technology (QST), Japan.This is the first mass spectrometry method which was evaluated and confirmed by an independent proficiency test.In this work, efforts were made to decrease the sample intake of stable strontium from µg to ng level, which can give the possibility of strontium isotope ratio analysis in low sample amount (mg level).This result can be interesting for meteorite as well as rock and sediment analysis.

Huge amounts of radiocesium, radiostrontium, and fission products were released into the atmosphere during the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. Therefore, it is necessary to determine the distribution coefficient of Cs and Sr in the soil-water system around FDNPP from the viewpoint of their migration. The determination of sorption coefficient Kd(S) as well as desorption coefficient Kd(D) for Cs and Sr has been carried out in the present study using the laboratory batch method. In this experiment, stable Cs and Sr were used for sorption on contaminated Fukushima soil samples and groundwater collected in proximity to the soil sample sites. Different soil parameters were measured to understand their effect on the sorption and desorption processes. Desorption experiments were carried out on some selected contaminated soil samples. Kd(S)-Cs and Kd(S)-Sr varied from 65 to 2100 L/kg and 15 to 130 L/kg, respectively. Kd(D)-Cs and Kd(D)-Sr varied between 75–2500 and 10–120 L/kg, respectively. High values of sorption coefficients for Cs indicate sorption capacity of soils for Cs is more than Sr. For Cs, Kd(D) was higher than Kd(S) whereas for Sr, Kd(S) was either equal to or higher than Kd(D). A moderate Pearson’s correlation of (Kd) Cs and Sr with exchangeable cations (Al, K, Mg, and Na) supported that ion exchange sorption mechanism is significant. There is enhanced Cs sorption compared to Sr due to the presence of biotite, kaolinite and smectite minerals resulting in high mobility of Sr in the Fukushima environment. We concluded retention capacity of Fukushima soils for Cs is moderately stronger than Sr, which supports Sr is more mobile in the environment.

In order to estimate occupational exposure of workers in a therapeutic radon spa facility, radon concentration in the workplace air was investigated at Markhot Ferenc Hospital, Eger, Hungary. The investigated balneotherapeutic facility and its natural hot spa water are used for treatments and rehabilitations of rheumatic patients. Radon concentration, radon decay products at a bathhouse, treatment rooms and a consultation room were continuously measured in August and September 2018. In the present study, different levels of radon concentration among the observation sites and its clear temporal variations were found, though radon concentrations in the investigated sites were below 300 Bq m-3. Regarding such radon fluctuation and low equilibrium factor level (0.1), the annual effective doses of workers are estimated to be around 0.5 mSv year-1.

A novel method for the determination of ultra-trace level 90Sr has been recently developed applying thermal ionization mass spectrometry (TIMS). The method includes the chemical separation of Zr (isobaric interference of 90Zr) from the samples followed by determination of 90Sr/88Sr abundance sensitivity (2.1 × 10−10). The analytical performance of this method was assessed in the IAEA-TEL 2017-3 worldwide open proficiency test. For 90Sr determination, tap water and milk powder samples were distributed amongst the participant laboratories with reference values of 11.2 ± 0.3 Bq kg−1 (2.2 ± 0.1 fg g−1) and 99.9 ± 5.0 Bq kg−1 (19.5 ± 1.0 fg g−1), respectively. The stable Sr concentrations were 39.4 ± 0.9 ng g−1 and 2.5 ± 0.1 µg g−1 while the 90Sr/88Sr isotope ratios were 6.47 ± 0.17 × 10−8 and 9.04 ± 0.45 × 10−9 in the tap water and milk powder samples, respectively. For TIMS measurement, 50 mL water and 1 g milk powder samples were taken for analysis. This TIMS method demonstrated an impressive accuracy (relative bias of 4.2% and −2.1%, respectively) and precision (relative combined uncertainty of 4.1% and 7.6%, respectively) when compared with radiometric techniques. For the first time in the history of inorganic mass-spectrometry, 90Sr analysis using a TIMS instrument is confirmed by an independent proficiency test.

The uranium concentration in some selected Japanese river waters after Fukushima Daiichi Nuclear Power Plant (FDNPP) accident was measured using inductively coupled plasma mass spectrometry (ICP-MS). We report distribution of uranium in seven prefectures of Japanese rivers covering 120 sampling points. The U concentration lies in the range of 0.13 ± 0.01–590 ± 9.93 ng L−1 with a mean value of 54.7 ± 100 ng L−1. The measured uranium content has been found to be less than the drinking waters limit of 30.0 µg L−1 recommended by the World Health Organization.

Inorganic mass spectrometry has been used as a well-known analytical technique to determine elemental/ isotopic composition of very diverse materials, based on the different mass-to-charge ratios of the ions produced in a specific source. In this case, two mass spectrometric techniques are explained and their analytical properties discussed: inductively coupled plasma mass spectrometry (ICP-MS) and thermal ionisation mass spectrometry (TIMS), since they are the most used in art and archaeological material studies. Both techniques combine advantageous analytical properties, like low detection limits, low interferences and high precision. The use of laser ablation as sample introduction system in ICP-MS allows to avoid sample preparation and to perform good spatial-resolution analysis. The development of new instruments, improving the mass separation and the detection of the ions, specially multicollection detectors, results in high-precision isotopic analysis. A summary of the important applications of these mass spectrometric techniques to the analysis of art and archaeological materials is also highlighted.

In this work, a new 90Sr analysis method was developed using the Isotopx Ltd., Phoenix X62 thermal ionization mass spectrometer (TIMS). Excellent ion beam sensitivity was demonstrated with the detection of 1 mBq (0.2 fg) 90Sr on a Daly ion-counting system. The abundance sensitivity for the 90Sr/88Sr ratio was 2.1 × 10-10, and this could ensure measurement of 100 Bq·kg-1 (19 fg·g-1) 90Sr in an environmental sample with 100 μg·g-1 stable strontium concentration. For analytical method validation, 90Sr was determined in two certified reference materials, for example, wild berry (IRMM-426) and freshwater lake sediment (NIST-4354), for the first time in the history of TIMS. This mass spectrometry method is faster than conventional radiometric techniques; however, interference from 90Zr and peak tailing on the higher mass side from 88Sr must be considered for a reliable 90Sr determination.

The main contribution to population exposure is due to radon and thoron progenies and not radon itself. The aim of this study was therefore to estimate annual effective dose using the results of Direct Radon and Thoron Progeny Sensors were exposed in 69 selected schools and 319 dwellings in several regions of Balkans: in Serbia: regions of Sokobanja and Kosovo and Metohija, Republic of Macedonia, Republic of Srpska and Slovenia. Obtained average total effective doses are in the range from 0.22 mSv a(-1) (schools in Republic of Srpska) to 2.5 mSv a(-1) (dwellings in Kosovo) and are below the reference level of 10 mSv a(-1) recommended by International Commission on Radiological Protection.