Cs-137 Activity Concentrations Research Articles

Study on the relationship between the dispersal of wild boar (Sus scrofa) and the associated variability of Cesium-137 concentrations in its muscle Post-Fukushima Daiichi Nuclear Power Plant accident

After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, the wild boar (Sus scrofa) population within the Fukushima Evacuation Zone (FEZ) increased substantially in size and distribution. This growing population and their potential dispersal from the FEZ, where they are exposed to high levels of radionuclides, into the surrounding landscape underscores the need to better understand boar movement patterns in order to establish policies for managing shipping restrictions for boar meat and develop management strategies. In this study, we quantified the genetic population structure of boar in and around Fukushima prefecture using sequence data of the mitochondrial DNA control region and MIG-seq analysis using 348 boar samples to clarify boar dispersal patterns. Among boar samples, seven Asian haplotypes and one European haplotype were detected. The European haplotype originated from hybridization between domestic pigs and native boar in the evacuation zone after the accident and was detected in 15 samples across a broad geographic area. Our MIG-seq analysis revealed genetic structure of boar was significantly different between boar inhabiting the eastern (including FEZ. i.e., East clade) and western (i.e., West clade) regions in Fukushima prefecture. In addition, we investigated the relationships between boar dispersal and Cesium (Cs)-137 activity concentrations in boar muscle using MIG-seq genetic data in Nihonmatsu city, located in the central-northern region of Fukushima. High Cs-137 activity concentrations, exceeding 1000 Bq/kg, in boar muscle had a significantly high probability of belonging to the East clade within localized regions. Thus, our results provide evidence of the spatial scale of dispersal of individuals or offspring of boar from the FEZ. Results of this research also indicate that dispersal of individuals between areas with different Cs-137 contamination levels is one of the biggest factors contributing to variation in Cs-137 activity concentration in boar muscle within localized regions.

Activity Concentrations of Cs-137, Sr-90, Am-241, Pu-238, and Pu-239+240 and an Assessment of Pollution Sources Based on Isotopic Ratio Calculations and the HYSPLIT Model in Tundra Landscapes (Subarctic Zone of Russia)

The paper is devoted to the assessment of the content of anthropogenic radionuclides in tundra landscapes of the subarctic zone of Russia. The authors of the article studied the features of accumulation and migration of anthropogenic radionuclides and identified probable sources of their entry into environmental objects. Peat samples were collected on the territory of the Kaninskaya Tundra of the Nenets Autonomous Okrug (Northwest Russia). A total of 46 samples were taken. The following parameters were determined in each peat sample: (1) activity and pollution density of anthropogenic radionuclides; (2) isotopic ratios of anthropogenic radionuclides; (3) activity ratios of each radionuclide for layers 10–20 cm and 0–10 cm. The results of the studies showed that the pollution density of the Nes River basin with the radionuclides Cs-137 and Sr-90 is up to 4.85 × 103 Bq×m−2 and 1.88 × 103 Bq×m−2, respectively, which is 2–5 times higher than the available data for the Kanin tundra, as well as for Russia and the world as a whole. The data obtained for Am-241, Pu-238, and Pu-239+240 showed insignificant activity of these radionuclides and generally correspond to the values for other tundra areas in Russia and the world. It was found that some tundra areas (“peat lowlands”) are characterized by increased radionuclide content due to the process of accumulation and migration along the vertical profile. Calculations of isotope ratios Sr-90/Cs-137, Pu-238/Pu-239+240, Pu-239+240/Cs-137, Am-241/Pu-239+240 and air mass trajectories based on the HYSPLIT model showed that the main sources of anthropogenic radionuclide contamination are global atmospheric fallout and the Chernobyl accident.

Wild bilberries – Superfood or health risk

Wild bilberries (Vaccinium myrtillus L.) were collected from 23 sites in Finland, dried, ground, homogenized and pressed into pellets. The pellets were irradiated in air with a 3 MeV proton beam from the Åbo Akademi MGC-20 cyclotron. The induced X-rays were measured, and elemental concentrations were calculated from the peak areas in the spectra. Elemental concentrations for K, Ca, Mn, Fe, Cu, Zn, Rb, and Sr were found to be above the detection limit of the method. A special focus was set on the high concentration of Mn (27 ± 16 µg/g). Already by consuming 100 g of fresh wild-grown bilberries the Recommended Dietary Allowance value for an adult male was exceeded. A child of 4–8 years old will reach the Tolerable Upper Intake Level of Mn (3 mg/day) by eating somewhat more than 100 g of bilberries in a day. In addition, the regional differences in elemental concentrations were found to be higher than earlier reported. The activity concentrations of Cs-137 in some of the bilberry samples were also measured and the equivalent dose to a person that annually consumes 2 kg of bilberries was found negligible (about 1 µSv).

Activity Concentrations of Sr-90 and Cs-137 in Seawater and Sediment in the Gulf of Tonkin, Vietnam

In this study, we measured the activity concentrations of Cs-137 and Sr-90 in surface seawater and surface sediments at the Tra Co, Bach Long Vi, and Ky Anh locations in the Gulf of Tonkin, Vietnam, from December 2018 to October 2019. The average activity at the selected locations was 1.22, 1.43, and 1.33 Bq/m3 for Cs-137 and 0.88, 1.17, and 1.09 Bq/m3 for Sr-90 in surface seawater samples and 0.74, 1.01, and 0.81 Bq/kg dry for Cs-137 and 0.49, 0.49, and 0.43 Bq/kg dry for Sr-90 in sediment samples. The ratio of the average activity concentration (Cs-137/Sr-90) in the surface seawater was 1.42, 1.22, and 1.22 at the Tra Co, Bach Long Vi, and Ky Anh locations, respectively. These are somewhat low compared to the global ratios (1.6 and 1.8). Meanwhile, Cs-137/Sr-90 ratios in the sediment samples at the selected locations were 1.51, 2.06, and 1.88, respectively, which is equal to or greater than the corresponding value for global sedimentation according to the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). Correlations between Sr-90, Cs-137, and organic carbon content were detected in this study. The results showed that Cs-137 has a high correlation with the organic carbon content in sediment, while Sr-90 has a low correlation.

Radiological characterization of the irt-5000(14-Tammuz) research nuclear reactor at Al-Tuwaitha nuclear center in Iraq

Measurements were made at the destroyed nuclear reactor IRT-5000 (14-Tammuz research nuclear reactor at AL-Tuwaitha Nuclear Center in Iraq) to provide a basic comprehensive radiological characterization and to assess risk and dose for the workers in the workplace. Samples were collected from the site and analyzed, as well as using a portable survey meter to determine the external exposure dose rates. The quantity and quality of radionuclides were determined using gamma spectrometry techniques. The dose rate measured within the reactor core body ranged from 55 to 1250 mSv/h. The maximum dose was recorded in the middle of the corner near the horizontal experimental channel number seven, with activity concentration of 19.97 GBq estimated from Co-60 isotope. Most samples were contaminated with Cs-137, Co-60, and Eu-152 isotopes. The highest activity concentration of Cs-137 is 14772.41 ± 99.91 Bq/L and Co-60 is 7642.22 ± 40.02 Bq/kg, were found in slag from reactor tank. Two scenarios were developed based on the water level of the reactor tank. Assuming there are three locations for workers on the reactor surface. The annual dose of workers on the surface of the reactor (when the reactor tank is empty) ranges from 116 to 153 mSv, which is higher than the annual dose limit for workers. Therefore, workers will be subjected to the principle of As Low As Reasonable Achievable (ALARA) during all phases of dismantling nuclear reactor IRT-5000 (14-Tammuz) as recommended by International Atomic Energy Agency (IAEA).

Marine radioactivity of Cs-134 and Cs-137 in the Malaysian Economic Exclusive Zone after the Fukushima accident

Seawater, sediment, biota and seaweed samples were collected in the Malaysian Economic Exclusive Zone (EEZ) marine environment within April 2012 to April 2014 as part of the marine radioactivity monitoring activities following the Fukushima Daiichi Nuclear Power (FDNPP) accident. The objectives of this study were to quantify radioactivity releases of Cs-134 and Cs-137 from the FDNPP into the Malaysian EEZ marine environment and to evaluate its potential impact on radionuclide levels in the marine life. The results showed Cs-134 in seawater, sediment and; biota and seaweeds were ranged from 1.3 to 2.2 Bq m−3, 1 to 1.9 Bq kg−1 dw. and < 0.01 to 0.2 Bq kg−1 fw., respectively. The levels of Cs-137 and Cs-134 as a radioisotopic signature for FDNPP discharges indicated that no new inputs into Malaysian marine environment, thus definitely confirmed the radioactive water released from FDNPP accident does not contaminate our marine environment. The estimated total dose and risk quotient using ERICA Assessment Tool showed the Cs-137 activity concentration in Malaysian marine environment was far below the screening value and does not cause any risk to the living organism. Thus, all our seafood including seaweeds are safe for human consumption.

Bio accumulation of radioactive caesium in marine mammals in the Baltic Sea – Reconstruction of a historical time series

Radionuclides from the Chernobyl accident in 1986 still circulate in the Baltic marine ecosystem and activity levels in water, sediments and fish species such as herring and perch are monitored annually. However, the activity levels of radionuclides in marine mammals have only been sporadically reported. Tissue samples from a museum collection were analysed in two species of seals, and the trends over time in activity level of radioactive caesium (Cs-137) after the Chernobyl accident were reconstructed. We also performed a literature review summarizing activity levels in marine mammals world-wide. We found activity concentrations of Cs-137 in Baltic ringed seals and grey seals to be elevated also in the most recent samples, and during the entire study period measurements ranged between 19 and 248 Bq/kg wet weight. A declining trend in time over the last 30 years follow the general trend of decline in activity levels in other Baltic biota. Accumulation was found to be species specific in the two seal species studied, with 9 times higher activity concentration in grey seals compared to herring, and 3.5 times higher in ringed seals compared to herring. We discuss potential paths and rates of bioaccumulation of radioactive caesium in the Baltic Sea including species specific prey choice of the two seal species and estimate life time exposure. The study contributes one important piece of information to predictive models in risk assessments for nuclear accidents.

Cs-137 in milk, vegetation, soil, and water near the former Soviet Union's Semipalatinsk Nuclear Test Site.

The present study was carried out to evaluate Cs-137 activity concentration in soil, water, vegetation, and cow's milk at 10 locations within three regions (Abai, Ayaguz, and Urdzhar) to the southeast of the Semipalatinsk Nuclear Test Site (SNTS) in Kazakhstan. Cs-137 activity concentrations, determined using a pure Ge gamma-ray spectrometer, showed that, all samples collected did not exceed the National maximum allowable limits of 10,000 Bq/kg for soil, 100 Bq/kg for cow's milk, 74 Bq/kg for vegetation, and 11 Bq/kg for water. Cs-137 is, therefore, not considered a health hazard in these regions. The highest levels of contamination were found in the Abai region, where the highest activity concentration of Cs-137 was 18.0 ± 1.0 Bq/kg in soil, 7.60 ± 0.31 Bq/kg in cow's milk, 4.00 ± 0.14 Bq/kg in the vegetation, and 3.00 ± 0.24 Bq/kg in water. The lowest levels were measured within the Urdzhar region, where 4.00 ± 0.14 Bq/kg was found in the soil, 0.30 ± 0.02 Bq/kg in the cow's milk, 1.00 ± 0.03 Bq/kg in the vegetation, and 0.20 ± 0.02 Bq/kg in the water.

Influence of K on the transport of Cs-137 in soil–plant root and root-leaf systems in sugar beet

The main aim of this study was to determine the influence of K-40 activity in the soil on the transport of Cs-137 from the soil to plants and the impact of its activity on the internal transport of Cs-137 between anatomical parts of the sugar beet. The activity concentration of Cs-137 in the soil was bigger than that in the beet. The highest activity concentration of K-40 was observed in beet leaves, while its content in roots and the soil were comparable.

Daily variation of I-131, Cs-134 and Cs-137 activity concentrations in the atmosphere in Osaka during the early phase after the FDNPP accident

To investigate the time variations of radionuclides discharged from the Fukushima Daiichi nuclear power plants accident, we started collecting aerosol samples in Osaka, Japan, using a high-volume sampler from March 15 to May 1, 2011. Atmospheric radioactivity concentrations of I-131, Cs-134 and Cs-137 were measured with germanium semi-conductor detectors. Only I-131 was detected in the early phase and two Cs-134.137 peaks were found in Osaka in April. Using the HYSPLIT model, we concluded that direct transportation of the air mass from the Fukushima area was responsible for such events.

Effects of a small-scale, abandoned gold mine on the geochemistry of fine stream-bed and floodplain sediments in the Horsefly River watershed, British Columbia, Canada

Mining is known to be a major source of metal contamination for fluvial systems worldwide. Monitoring and understanding the effects on downstream water and sediment quality is essential for its management and to mitigate against detrimental environmental impacts. This study aimed to examine the effects of the small-scale, abandoned, hydraulic Black Creek gold mine on the geochemical content of fine (&lt;63 μm) stream bed and floodplain sediment in the Horsefly watershed (British Columbia, Canada), which is a part of the Quesnel River basin. Concentrations of As, Cd, Se and Zn were determined byaqua regiadigestion and the modified BCR (European Community Bureau of Reference) sequential extraction procedure followed by inductively coupled plasma-optical emission spectroscopy or inductively coupled plasma-mass spectrometry. Age-depth models for the floodplain cores were constructed using excess Pb-210 and Cs-137 activity concentration profiles. The results show that the mine caused local As contamination of the Horsefly River floodplain sediment during the first years of operation, but at present the contamination is mainly contained in the Black Creek. Present-day and recent concentrations of Cd, Se and Zn in the Horsefly River are elevated and this is probably derived from other upstream mining activities. The spatial and temporal changes in heavymetal concentrations suggest a slight, but not particularly widespread, mining effect on the finesediment geochemistry in the Horsefly River system.

Investigation of Cs-137 and K-40 activities of natural spring waters of the Eastern Black Sea Region, Turkey

The activity concentrations of Cs-137 and K-40 radio nuclides in the natural spring waters of the Eastern Black Sea region of Turkey were measured using gamma-ray spectrometry. Annual effective dose equivalents of Cs-137 and K-40 in babies, children and adults were calculated from the obtained measurements. These results were compared with other studies and the limit values of World Health Organization. The activity concentrations were calculated and kriging-geostatistical method was used to plot the obtained data on the radioactive maps of Eastern Black Sea Region. Frequency distributions of the water samples for each province were determined. This study provides background values of investigated Cs-137 and K-40 in the water from the region, which could, also, be useful in forensic investigations to distinguish potential contributions from point pollution sources.

Natural and artificial radioactivity assessment of dam lakes sediments in Çoruh River, Turkey

In the sediment samples collected from 3 different dam reservoirs and 10 different stations on Coruh River, U-238, Th-232, K-40 and Cs-137 activity concentration levels were measured using high-resolution gamma-ray spectrometry. The mean concentrations of U-238, Th-232, K-40 and Cs-137 were found to be 15.8, 13.9, 551.5 and 18.1 Bq/kg in Deriner Dam Lake, 3.7, 12.5, 473.8 and 6.8 Bq/kg in Borcka Dam Lake, 14.4, 30.0, 491.7 and 18.2 Bq/kg in Muratli Dam Lake, respectively. Estimation calculations were made for the non-sampling zones by using Kriging method. Furthermore, results were compared with the similar studies done in different countries.

Cs-137 in the natural environment of the Gorce Mountains (Poland).

Concentration of activity of Cs-137 and its spatial distribution in soils and lichen Hypogymnia physodes were determined in the Gorce Mts. (several hundred km2) in S Poland. The authors distinguished two areas of the Gorce Mts. on the basis of markedly different Cs-137 depositions, whose respective average values are 4.4 and 9.9 kBq/m2 as at 1st July 2005. The average Cs-137 activity concentration in the lichen H. physodes from the Gorce is 47 Bq/kg d.m. A significant local variability of quantities measured amounts to a few dozen percent was found.

Depth and Areal Distribution of Cs-137 in the Soil of a Small Water Catchment in the Sopron Mountains

Abstract - The study presents the depth and areal distribution of Cs-137 activity concentration in the forest soils of Farkas Trench, a small water catchment in the Sopron Mountains, in 2001 and 2010, moreover the possible reason of the alteration in activity concentration. The Cs-137 activity values were measured in 30 plots in 2001, and in 5 in 2010. In 2001, the depth distribution of Cs-137 activity concentration in the measurement plots was shaped in accordance with a decreasing exponential function. It appeared in the 2010 data that the highest Cs-137 activity concentration had shifted lower from the top layers, and the depth distribution changed along an increasing or a stagnating function until a depth of 4 to 6 cm (in function of slope inclination), then along a decreasing function. In 2001, activity concentration in the surface soil layers (0 - 2 cm) altered between 15 and 609 Bq/kg, whereas in 2010 between 26 and 72 Bq/kg. A correlation was found between activity concentration in the surface soil layer and slope inclination. It was concluded that one of the main reasons for differences in distribution of Cs-137 activity concentration was the differing extent of soil movement.

Vertical distribution of anthropogenic radionuclides in cores from contaminated floodplains of the Yenisey River

The Mining and Chemical Industrial Combine, Zheleznogorsk (MCIC, previously known as Krasnoyarsk-26) on the River Yenisey has contaminated the surrounding environment with anthropogenic radionuclides as a result of discharges of radioactive wastes. The purpose of this study was to investigate the vertical distribution of anthropogenic contamination ( 137Cs and plutonium) within floodplain areas at different distances from the discharge point. Sites were chosen that display different characteristics with respect to periodic inundation with river water. Cs-137 activity concentrations were in the range 23–3770 Bq/kg (dry weight, d.w.); Pu-239,240 activity concentrations were in the range <0.01–14.2 Bq/kg (d.w.). Numerous sample cores exhibited sub-surface maxima which may be related to the historical discharges from the MCIC. Possible evidence indicating the deposition of earlier discharges at MCIC in deeper core layers was observed in the 238Pu: 239,240Pu activity ratio data: a Pu signal discernible from global fallout could be observed in numerous samples. Cs-137 and Pu-239,240 activity concentrations were correlated with the silt fraction (% by mass <63 μm) though no significant correlation was observed between (grain-size) normalised 137Cs activity concentrations and distance downstream from the MCIC.

Assessment of Committed Effective Dose due to consumption of Red Sea coral reef fishes collected from the local market (Sudan)

An assessment of Committed Effective Dose (CED) due to consumption of Red Sea fish containing 210Po and 137Cs was performed for 23 different marine fish samples collected from the local market at Port Sudan. The fish were classified according to their feeding habits into three categories: carnivores, herbivores, and omnivores. Measured activity concentrations of 210Po were found in the ranges 0.25–6.42 (carnivores), 0.7–5 (omnivores) and 1.5–3.8 (herbivores) Bq/kg fresh weight. In the same study, activity concentrations of Cs-137 were determined to be in the ranges 0.1–0.46 (carnivores), 0.09–0.35 (omnivores) and 0.09–0.32 (herbivores) Bq/kg fresh weight, which were several times lower than those of 210Po. Appropriate conversion factors were used to derive the CED, which was found to be 0.012, 0.01 and 0.01 (µSv/yr) in carnivores, omnivores and herbivores, respectively, for 137Cs. This contributes about 0.4% of the total dose exclusively by ingestion of fish. For 210Po, it was found to be 3.47, 4.81 and 4.14 (µSv/yr) in carnivores, omnivores and herbivores, respectively, which represents 99.6% of the total dose (exclusively by ingestion of fish). The results of CED calculations suggest that the dose received by the Sudanese population from the consumption of marine fish is rather small and that the contribution of 137Cs is negligible compared to 210Po.

The radiological environment of Svalbard

This paper presents a detailed survey of the radiological environment of the Svalbard area carried out from 2000 to 2002, in both the marine and terrestrial environment. In the marine environment in 2001, 99Tc activity concentrations in seawater were 0.13 to 0.36 Bq/m3, 5 fold higher than those in 1994, refl ecting the increase in 99Tc discharges from Sellafi eld in the mid 1990s. Cs-137 activity concentrations in seawater were 2.23 to 2.43 Bq/m3, ca. 10 fold lower than those in the 1980s, refl ecting the reduction in discharge of this radionuclide. Pu-238, 239+240Pu and 241Am activity concentrations in seawater were < 0.3 to 0.7 mBq/m3, 5.6 to 8.9 mBq/m3 and 0.6 to 2.4 mBq/m3 respectively, with activity ratios suggesting global fallout to be the dominant source. Tc-99 activity concentrations in brown algae were up to 18 fold higher than those in the 1980s with highest concentrations in Fucus distichus (25.7 to 58.7 Bq/kg d.w.). In the terrestrial environment, typical 137Cs activity concentrations in soil were between < 0.5 and 63 Bq/kg d.w. whilst activity concentrations of the natural radionuclides 238U (17 to 72 Bq/kg d.w.), 226Ra (21 to 70 Bq/kg d.w.), 232Th (10 to 57 Bq/kg d.w.) and 40K (115 to 818 Bq/kg d.w.) were similar to global averages. In terrestrial vegetation, 137Cs activity concentrations varied from 29 to 292 Bq/kg d.w. in mosses, 30 to 140 Bq/kg d.w. in lichen and 19 to 109 Bq/kg d.w. in fl owering plants. Elevated activity concentrations of 137Cs, 238U, 226Ra, Pu isotopes and 241Am were found in some matrices associated with seabird colonies.

The radiological environment of Svalbard

This paper presents a detailed survey of the radiological environment of the Svalbard area carried out from 2000 to 2002, in both the marine and terrestrial environment. In the marine environment in 2001, 99Tc activity concentrations in seawater were 0.13 to 0.36 Bq/m3, 5 fold higher than those in 1994, refl ecting the increase in 99Tc discharges from Sellafi eld in the mid 1990s. Cs-137 activity concentrations in seawater were 2.23 to 2.43 Bq/m3, ca. 10 fold lower than those in the 1980s, refl ecting the reduction in discharge of this radionuclide. Pu-238, 239+240Pu and 241Am activity concentrations in seawater were < 0.3 to 0.7 mBq/m3, 5.6 to 8.9 mBq/m3 and 0.6 to 2.4 mBq/m3 respectively, with activity ratios suggesting global fallout to be the dominant source. Tc-99 activity concentrations in brown algae were up to 18 fold higher than those in the 1980s with highest concentrations in Fucus distichus (25.7 to 58.7 Bq/kg d.w.). In the terrestrial environment, typical 137Cs activity concentrations in soil were between < 0.5 and 63 Bq/kg d.w. whilst activity concentrations of the natural radionuclides 238U (17 to 72 Bq/kg d.w.), 226Ra (21 to 70 Bq/kg d.w.), 232Th (10 to 57 Bq/kg d.w.) and 40K (115 to 818 Bq/kg d.w.) were similar to global averages. In terrestrial vegetation, 137Cs activity concentrations varied from 29 to 292 Bq/kg d.w. in mosses, 30 to 140 Bq/kg d.w. in lichen and 19 to 109 Bq/kg d.w. in fl owering plants. Elevated activity concentrations of 137Cs, 238U, 226Ra, Pu isotopes and 241Am were found in some matrices associated with seabird colonies.

Cs-137 in fuels and ash products from biofuel power plants in Sweden

The activity concentrations of Cs-137 in peat, wood chips and ash products from 13 Swedish district heating plants have been investigated during the winter seasons of 1986/87, 1988/89, 1989/90 and 1990/91. There is a significant decrease in the activity concentration of Cs-137 in the fuel which was especially pronounced between the first two seasons after the Chernobyl accident. In spite of the varying deposition of Cs-137 over the country it has been possible to find a relation between the activity concentration in the peat and wood chips, and the deposition. The total number of Swedish heating plants of which 35–40 are burning peat and 70–75 wood chips have been divided in three groups according to the activity concentration in the ash products. The mean Cs-137 concentration in ash and the total activity ‘produced’ per year in Sweden have been calculated. The maximum ground concentration and corresponding effective dose rate of inhaled Cs-137 as a function of the emission rates of flue gases from stacks with varying heights and during different Pasquill atmospheric stability conditions have been calculated.