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Inductively coupled plasma mass spectrometry (ICP-MS) has been used to measure the concentration of trace and rare earth elements (REEs) in soils. Geochemical certified reference materials such as JLk-1, JB-1, and JB-3 were used for the validation of the analytical method. The measured values were in good agreement with the certified values for all the elements and were within 10% analytical error. Beach placer deposits of soils mainly from Odisha, on the east coast of India, have been selected to study selected trace and rare earth elements (REEs), to estimate enrichment factor (EF) and geoaccumulation index (Igeo) in the natural environment. Enrichment factor (EF) and geoaccumulation index (Igeo) results showed that Cr, Mn, Fe, Co, Zn, Y, Zr, Cd and U were significantly enriched, and Th was extremely enriched. The total content of REEs ranged from 101.3 to 12,911.3 μg/g with an average 2431.1 μg/g which was higher than the average crustal value of total REEs. A high concentration of Th and light REEs were strongly correlated, which confirmed soil enrichment with monazite minerals. High ratios of light REEs (LREEs)/heavy REEs (HREEs) with a strong negative Eu anomaly revealed a felsic origin. The comparison of the chondrite normalized REE patterns of soil with hinterland rocks such as granite, charnockite, khondalite and migmatite suggested that enhancement of trace and REEs are of natural origin.

The Gd-based contrast agents utilized in MRI are removed renally without metabolization in the human body, and they enter the aquatic ecosystem without undergoing degradation processes when released in effluent of waste water treatment plants. In recent years, medical uses of Gd-based contrast agents have increased, and the amounts of anthropogenic Gd that have been released into the environment are increasing. In this study, the Gd anomalies in Hokkaido river waters were determined and comparisons were made to previously reported values. The range of anthropogenic Gd was 2.08 – 101.16 ppt with an average value of 20.56 ppt (n = 6), and the measurement revealed significant increases in the Gd anomalies with a maximum increase of 8.3 times larger compared to data obtained in 1995. These findings indicate there is a need to consider as effective removal method to protect the aquatic ecosystem.

A new chemical separation has been developed to isolate uranium (U) using two UTEVA columns to minimize iron and thorium interferences from high background area soil samples containing minerals like monazites and ilmenite. The separation method was successfully verified in some certified reference materials (CRMs), for example, JSd-2, JLk-1, JB-1 and JB-3. The same method was applied for purification of U in Fukushima soil samples affected by the Fukushima dai-ichi nuclear power station (FDNPS) accident. Precise and accurate measurement of 234U/238U and 235U/238U isotope ratios in chemically separated U were carried out using a multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). In this mass spectrometric method, an array of two Faraday cups (10e11 Ω, 10e12 Ω resistor) and a Daly detector were simultaneously employed. The precision of U isotope ratios in an in-house standard was evaluated by replicate measurement. Relative standard deviation (RSD) of 234U/238U and 235U/238U were found to be 0.094% (2σ) and 0.590% (2σ), respectively. This method has been validated using a standard reference material SRM 4350B, sediment sample. The replicate measurements of 234U/238U in SRM shows 0.7% (RSD). This developed method is suitable for separation of U and its isotope ratio measurement in environmental samples.

Fukushima dai-ichi nuclear power station (FDNPS) accident in March 2011 released huge amounts of volatile fission products such as 129mTe, 131I, 134Cs, and 137Cs with traces of U, Pu, Am, Cm, Np nuclides in the terrestrial area in the east Japan (Povinec et al., 2013). From the viewpoint of radiation protection, it is crucial to obtain sufficient data on U and Pu radioisotopes. Measurement of 236U/238U and 238Pu/137Cs ratios in soil could be used as tracers to identify source of contamination due to nuclear accident. Furthermore, concentrations of 236U and 238Pu will help to improve internal dose estimation. Therefore, Fukushima soils were selected based on 137Cs concentration. The 137Cs activity concentration ranged from 150 to 5000 Bq/g in soils collected from Okuma town within, The 6th International Conference on Environmental Radioactivity (ENVIRA 2021)

The Fukushima Dai-ichi Nuclear Power Station (FDNPS) accident caused a significant amount of 137Cs deposition in the Fukushima prefecture. In the present study, soil samples collected from the Namie-machi area with radiocesium contamination were considered. The 137Cs activity concentration of the soil samples ranged from 18 - 469 kBq/kg. MOX fuel was used in the FDNPS reactor. There may be spread of small amount of actinides into the environment as a result of partial melt-down of the reactor cores. It is a challenging task to distinguish between anthropogenic and natural U, since U abundances vary in Japan soils from 3.67-42.4 Bq/kg. Measurement of 235U isotope could play an important role to identify the source of contamination whether it is from FDNPS accident. Therefore, uranium activity ratio (234U/238U) and 235U/238U ratio in the soil samples were measured using multi-collector inductively coupled plasma mass spectrometry. The retention or mobility of radionuclides in soil is highly dependent on its distribution coefficient value. In our Kd studies, the U distribution coefficient value range was very high compared to the distribution coefficient of Cs in Fukushima soil samples (Mishra et al., 2019). The relationship between 137Cs activity concentration and U isotope ratio of soil sample are important to establish radionuclides dynamic in the environment after any accident. This can give information about the source of radionuclides released and the extent of damage and meltdown of reactors, which is still unclear at present. Further results will be presented in the meeting., Environmental Dynamics of Radionuclides and Biological Effects of Low Dose-Rate Radiation

There was a large distribution of 137Cs and 90Sr in surrounding environment of the damaged Fukushima dai-ichi nuclear power station (FDNPS). A soil column was collected after six years of the Fukushima accident (2017) in the Futaba city with elevated contamination at a hot spot with limited area (less than 1 sq m) to study the vertical migration of 90Sr. The 137Cs and 90Sr activity concentration results in 1cm sequences deep down to 5 cm were analyzed. The highest activity concentration for 137Cs and 90Sr was in the 3 cm section (11,718±12 kBq/kg and 758±37 Bq/kg, respectively whereas the lowest activity concentrations noticed in the 5 cm section (5,934±21 kBq/kg and 269±18 Bq/kg, respectively). The 90Sr/137Cs activity ratio is in the range of 4.53x10e-5 and 6.51x10e-5 which is significantly lower than the value of 2x10e-4 as reported by Hirose (2017). The explanation of the difference could be based on the result of the distribution coefficient (Kd) of Cs and Sr in the Fukushima soil samples. In our Kd studies, we observed Cs bound to the Fukushima soil particles is stronger than the Sr attachment (Kasar et al. 2021). Therefore, Sr has a more intensive migration pattern and it is reflected in the decrement of 90Sr/137Cs activity ratio from 2x10e-4 to 4.53x10e-5 during five years. The 90Sr migration has a sharp break after 3 cm and in the 5 cm section the 90Sr contamination is around three times lower than in the 3 cm section. Deeper sections below 5 cm are also contaminated slightly but need further investigation to confirm the assumption., Environmental Dynamics of Radionuclides and Biological Effects of Low Dose-Rate Radiation

There is a great demand for rapid measurement of Sr-90 in environmental samples after the Fukushima Dai-ichi nuclear power station (FDNPS) accident. 90Sr (t1/2 = 28.8 y) is one of the most common and hazardous fission products released by a nuclear reactor accident. Measurement of 90Sr using radiometric methods is a time consuming process since it involves a complex sample preparation and analytical separation required to produce reliable data. Thermal ionization mass spectrometry (TIMS) is the technique of choice because of its inherent high precision and accurate measurement of isotopic ratio. Typical abundance sensitivity for strontium isotope ratio measurement with conventional TIMS is about 10-7. The perfect chemical separation of radiocesium from Sr-90 is a cardinal point to gain accurate Sr-90 result as the radiocesium also undergoes beta decay emitting gamma-rays. A new 90Sr analysis method was developed using the Isotopx Ltd., Phoenix X62 TIMS. The abundance sensitivity for the 90Sr/88Sr ratio was 2.1×10 10 and this could ensure detection limit of 100 Bq·kg 1 (19 fg·g 1) 90Sr in Fukushima soil samples. The method has been validated using two certified reference materials e. g. wild berry (IRMM-426) and freshwater lake sediment (NIST-4354). This mass spectrometry method is faster than conventional radiometric techniques., 福島大学環境放射能研究所第8回成果報告会

Natural uranium comprises of three natural isotopes such as 238U, 235U and 234U with relative isotopic abundances of 99.27%, 0.72% and 0.0055%, respectively. The concentration of uranium in Japanese rivers water ranged from 0.13 to 590 pg mL-1 with a mean value of 54.7 pg mL-1, which is three magnitudes lower than World Health Organization (WHO) recommended value (30 µgL-1). Hence, the isotope ratios measurement of 234U/238U and 235U/238U in low concentrated water samples is a challenging task. The 234U/238U and 235U/238U isotope ratios were measured using a multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). The combination of 1012 Ohm resistor Faraday cup and Daly detectors are used for low abundance of 234U measurement. A standard solution containing 50 pg mL-1 of U was selected for accuracy and precision measurement of 234U/238U and 235U/238U isotope ratios. MC-ICP-MS coupled with desolvating nebulizer system could measure U isotope ratios at picogram level in ground water, river water, pond water and stream water from Fukushima prefecture. The DGA-normal extraction chromatography resin was used for the chemical separation of U from other elements in water samples. Further data will be present during presentation., 福島大学環境放射能研究所第8回成果報告会

Some reports have already published that the total amounts of 137Cs and 90Sr released due to the Fukushima Daiichi Nuclear Power Station (FDNPS) accident were estimated to be approximately 15 PBq and 0.14 PBq, respectively. The migration of deposited radionuclides of Cs, Sr and U on soils could take place to the local environment. From this viewpoint, it is necessary to determine the distribution coefficients of Cs, Sr and U in the soil-water system around FDNPS. Sorption Kd(S) and desorption Kd(D) coefficients has been estimated using the laboratory batch method for the soils collected from Fukushima prefecture including Namie and Okuma Towns. High values of sorption coefficients for Cs and U implied sorption capacity of soils for Cs and U was more than Sr. The difference between sorption coefficient values of Cs and U was less in Okuma Town soils unlike to other soils. For Cs and U, Kd(D) was higher than Kd(S) whereas for Sr, Kd(S) was either equal to or higher than Kd(D). Overall, it revealed that unsorbed Sr could migrate farther than unsorbed Cs or U under the present experimental conditions., 福島大学環境放射能研究所第8回成果報告会

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 e.g. 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.

90Sr analyses using thermal ionization mass spectrometry (TIMS) has reduced analysis time significantly and the enhancements in detection sensitivity have improved the detection limit to the ultra-trace level (fg range). Detection limit of 90Sr, 1 mBq (0.2 fg) could be further improved with larger ion beams.

The precise isotope measurement of Te in terrestrial and extraterrestrial material is essential to check the isotopic heterogeneities attributable to incomplete mixing of r and s-processes products. MC-ICP-MS measurement has improved in accuracy and precision compared to NTIMS due to ionization of a greater proportion of Te atoms. Therefore, in the present study, we report Te isotope composition of terrestrial standards using NTIMS and MC-ICP-MS to check the precision and reproducibility of both instruments. Especially the use of 1012 Ω resistor for 120Te isotope in MC-ICP-MS enhanced the reproducibility and increased the result of 120Te/128Te ratio by one order magnitude compare to the NTIMS data and previous studies. Thus, it illustrates that the MC-ICP-MS and NTIMS produce better precision and reproducibility for Te isotope ratio measurement., 32nd ISMAS Symposium on Mass Spectrometry

Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted radioactive contamination in soil due to deposition of mainly radiocesium as well as many long-lived radionuclides surrounding a large area around FDNPP. Depending upon environmental conditions, radionuclides in soil can be mobilized in aquatic systems. Therefore, the fate and transfer of these radionuclides in the soil water system is very important for radiation protection and dose assessment. In the present study, soil and water samples were collected from contaminated areas around FDNPP. Inductively coupled plasma mass spectrometry (ICP-MS) is used for total uranium concentration. Emphasis has been given on isotope ratio measurement of 235U/238U ratio using thermal ionization mass spectrometry (TIMS) that gives us the idea about its contamination during accident. For the migration behavior, its distribution coefficient (Kd) has been determined using laboratory batch method. Chemical characterization of soil with respect to different parameters has been carried out. The effect of these soil parameters on distribution coefficient of uranium has been studied in order to explain the radionuclide mobility in this particular area. The distribution coefficient values for uranium are found to vary from 30 to 36000 L/kg. A large variation in the distribution coefficient values shows the retention or mobility of uranium is highly dependent on soil characteristics in the particular area. This variation is explained with respect to soil pH, Fe, Mn, CaCO3 and organic content. There is a very good correlation of uranium Kd obtained with Fe content. There is no enrichment of 235U has been noticed in the studied area.

A preliminary study was carried out to determine the radioactivity concentration of 232Th, 226Ra and 40K in beach placer sands from 13 locations along the coast line of Tamil Nadu state, India. The ambient dose rates varied from 9 to 467 nGy h−1. The activity concentrations of radionuclide 232Th, 226Ra and 40K ranged from 5.2 to 683 Bq kg−1, 13 to 198 Bq kg−1 and 107 to 421 Bq kg−1, respectively. The annual effective dose rate ranges from 27 to 620 μSv y−1 and was higher at seven beaches in comparison to the UNSCEAR annual worldwide average value.