137Cs Concentrations Research Articles

Radioactivity concentration of natural and anthropogenic radionuclides in the soil of Banswara region, Rajasthan and associated radiation index parameters

Abstract Activity concentrations of gamma-emitting naturally occurring radionuclides (NORM’s) of 226Ra, 232Th, and 40K along with anthropogenic radionuclides of 137Cs in soil samples collected around the new upcoming nuclear power plant site at Banswara district, of Rajasthan, India were estimated. The mean radioactivity concentrations of 226Ra, 232Th, 40K, and 137Cs in surface soil samples of Banswara region were 17.6, 36.4, 309.7, and 1.4 Bq.kg−1, respectively. The mean activity of 226Ra, 232Th, and 40K is lower when compared to the world average values. Average radium equivalent activity (Raeq), absorbed gamma dose rates in air (DR), and annual effective dose (AED) for the soil of the study area are calculated as 94.0 Bq.kg−1, 43.0 nGy.h−1, and 0.26 mSv.y−1, respectively. Estimated AED to the general public is 0.24 mSv.y−1, which is comparable to the global values due to terrestrial radiation. These radiological index parameters were compared with internationally approved values and the recommended safety limits. The study and analysis of collected soil samples from the Banswara region of Rajasthan indicate that the soil of this area does not pose any significant radiological health hazard to the people residing in adjacent areas. Multivariate Statistical analysis of Pearson correlation and analysis of variance (ANOVA) has been carried out. The result of ANOVA test indicated that there is no remarkable difference in the total variance of radioactivity of NORMs with respect to distance and it also indicated that the soil of the area belongs to a similar lithologic origin. The Pearson correlation of 226Ra with 232Th (r = 0.53) and 40K (r = 0.68) showed a fairly positive correlation, suggesting that their content in soil samples were mostly influenced and controlled by sources of similar origin. Spatial distribution maps using the kriging interpolation algorithm have been generated for the 30 km × 30 km area.

Development and optimization of electrosprayed vitamin C - chitosan nanoparticle: A CCD-RSM approach and characterization of bioactive encapsulant

Electrospraying for Vitamin C (VC) encapsulation in Chitosan (Cs) nanoparticles was investigated and particle size, zeta potential, loading capacity (LC%) and encapsulation efficiency (EE%) were examined. Cs concentration (1–2% w/v) and voltage (21-25 kV) were varied with VC (0.25–0.75 w/w Cs). Twenty experiments in a face-centered CCD-RSM design were evaluated. ANOVA suggested voltage and Cs concentration as significant factors for particle size and VC content affected zeta, LC and EE%. RSM proposed optimum processing parameter at 2% Cs, 0.746 VC: Cs mass ratio and 21 kV voltage with 251.1 ± 59.03 nm particle size, 36.6% LC and an EE of 85.42%. Encapsulated particles were subjected to release behaviour, antioxidant property and analyzed through FTIR, DSC and XRD. Encapsulated VC had better antibacterial properties than Cs nanoparticles, and comparable VC retention in apple juice showed its effectiveness. Overall, nanoencapsulation of VC using electrospraying was successfully developed to be used in numerous food processing applications.

Behavior of <sup>137</sup>Cs in the soil-plant system in the floodplain landscapes of the Sozh River basin

Studies were carried out in the most affected by the Chernobyl accident part of the Bryansk region, in the ecosystems of floodplains of the Iput, Besed and Unecha rivers, in zones with different 137Cs pollution density. The purpose of the work is to study the peculiarities of the vertical distribution of 137Cs in the soil–plant system of the floodplain landscape long after the Chernobyl accident. As a result of studies, it was revealed that the vertical distribution of 137Cs, in the 0–20 cm layer, is determined by the position on the relief and the genesis of the soils of floodplain subsystems. The distribution character can be uniform, decreasing with depth, or with accumulation in certain layers. In the floodplain ecosystem, the concentration of 137Cs in the 0–20 cm layer increases from the river channel to the terrace above floodplain subsystems. Currently, the use of the territory of the west of the Bryansk region with a 137Cs pollution density above 555 kBq/m2 in feed production is strictly limited. The coefficient of 137Cs transition from soil to plants decreases from the central part to the near-channel one and to terrace above floodplain.

Radioactivity of Technosols on thermal power station ash disposal sites: Assessment of potential radiological human‐health risk

AbstractSoil radioactivity is a poorly recognized form of land degradation; however, there are regions all around the world where it can be dangerous to the environment and human health. The aim of the study was to analyze the radioactivity of Technosols developed on thermal power station (TPS) ash disposal sites. Total concentration of uranium (U), thorium (Th), and cesium (Cs), as well as the radioactivity of select radionuclides in Technosols were determined to recognize the level of radioactivity and to assess the potential radiological health risk. Total U, Th and Cs concentrations in Technosols were in ranges 1.5 to 11.3, 4 to 22.9, and 0.2 to 21.3 mg·kg−1, respectively. The radioisotope activities in Technosols (in Bq·kg−1) were in the 1.6–25.5 (137Cs); 29.2–1265 (40K); 26.2–99.9 (228Th); 27.9–100 (228Ra); 20.5–134. (226Ra); 32.8–177 (210Pb); 23.9–144 (238U); 1.2–7.0 (235U) ranges. The activity concentrations were slightly higher than the activities of non‐contaminated soils. Technosols developed from bituminous coal ash had higher 40K, 228Th, and 228Ra activity concentrations than soils developed from lignite ash. Artificial 137Cs occurred in surface horizons of Technosols due to fall of atmospheric dust enriched in 137Cs. Annual effective dose (AED) in Technosols amounted 0.07–0.16 mSv·a−1 and was somewhat higher than the global and Polish average (0.06 and 0.07 mSv·a−1, respectively) for outdoor external terrestrial radiation. The radioactivity of the investigated Technosols is slightly above the average radioactivity of native soils. The radiological human‐health risk related to the analyzed soils is low.

Temporal trajectories of artificial radiocaesium 137Cs in French rivers over the nuclear era reconstructed from sediment cores

137Cs is a long-lived man-made radionuclide introduced in the environment worldwide at the early beginning of the nuclear Era during atmospheric nuclear testing’s followed by the civil use of nuclear energy. Atmospheric fallout deposition of this major artificial radionuclide was reconstructed at the scale of French large river basins since 1945, and trajectories in French nuclearized rivers were established using sediment coring. Our results show that 137Cs contents in sediments of the studied rivers display a large spatial and temporal variability in response to the various anthropogenic pressures exerted on their catchment. The Loire, Rhone, and Rhine rivers were the most affected by atmospheric fallout from the global deposition from nuclear tests. Rhine and Rhone also received significant fallout from the Chernobyl accident in 1986 and recorded significant 137Cs concentrations in their sediments over the 1970–1985 period due to the regulatory releases from the nuclear industries. The Meuse River was notably impacted in the early 1970s by industrial releases. In contrast, the Seine River display the lowest 137Cs concentrations regardless of the period. All the rivers responded similarly over time to atmospheric fallout on their catchment, underlying a rather homogeneous resilience capacity of these river systems to this source of contamination.

Uncertainty analysis of 137Cs measured by shipborne device for radioactive monitoring

Uncertainty is a crucial indicator of the performance of monitoring devices. Analyzing and calculating uncertainty is a necessary prerequisite for accurately presenting the results of radioactive monitoring for seawater. This paper evaluates the uncertainty involved in the measurement process of the developed radioactive monitoring device. By measuring the different activity concentrations of 137Cs in seawater samples from around a nuclear power plant, and comparing these measurements with radiochemical analysis results. The results show that the main factors affecting the uncertainty of the device are the uncertainty of the γ count rate of seawater sample, the γ count rate and volume of the standard source, with the uncertainty of the γ count rate of seawater sample being the most significant contributor.

Downward migration of 137Cs promotes self-cleaning of forest ecosystem by reducing root uptake of Japanese cedar in Fukushima

Approximately 70 % of the area highly 137Cs-contaminated by the Fukushima Daiichi Nuclear Power Plant accident is forested. Decontamination works in most of these forests have not progressed, and the forestry industry remains stagnant. Although the long-term dynamics of 137Cs in the forest ecosystem will be controlled by the amount of 137Cs absorbed by roots in the future, temporal changes in 137Cs of tree roots have rarely been reported. In the present study, we monitored the depth distribution of 137Cs in the soil and absorptive very fine (VF) roots of 0.5 mm or less in a Japanese cedar forest from 2011 to 2023. As a result, the 137Cs inventory in the mineral soil increased over time due to the migration from the forest canopy and litter layers, whereas that in the VF roots tended to decrease since 2020, although there was a large variation. Temporal decrease in the exchangeable 137Cs fraction with fixation and temporal increase in VF root biomass with their growth were not clearly observed, the 137Cs concentration in the VF roots at 0–2 cm decreased with the decrease in 137Cs concentration in the litter layers. Although the 137Cs concentration in the VF roots below 2 cm tended to increase with increasing 137Cs concentration in the soil at the same depth, the downward migration of 137Cs within the soil can reduce the amount of 137Cs absorbed by roots because the VF root biomass decreases exponentially with depth. In other words, 137Cs can be removed from the long-term active cycles of forest ecosystems as they migrate deeper into the soil. This natural migration process can be regarded as a “self-cleaning” of the forest ecosystem, the green and sustainable remediation using such self-cleaning should be actively adopted for the future forest management.

Investigation of radioactivity concentrations and soil-to-plant transfer factors in soil samples taken from different distance zones to the Metsamor nuclear power plant

Abstract Monitoring radioactivity around nuclear power plants is important to avoid the risks of radiation. This study provides an overview of the radioactive emission impact on the near surroundings of the Metsamor nuclear power plant in Armenia. In this context, 29 soil samples were collected from the 40, 80, 120, 160 km radius areas determined in the direction of Iğdır province by accepting the Metsamor nuclear power plant as the center. The activity concentrations of 226Ra, 232Th, 40K and 137Cs in soil samples ranged from 7.90 to 23.44, 7.11 to 33.55, 132.54 to 502.69 and 0.33 to 17.61 Bq/kg, respectively. In addition, the radioactivity concentrations in some agricultural products and the transfer factors from soil to plant were determined. As a result, there is no significant radiological risk in terms of studied radioisotopes for people living in this region.

The Design of a Parameterization Scheme for 137Cs Based on the WRF-Chem Model and Its Application in Simulating the Fukushima Nuclear Accident

Based on the Weather Research and Forecasting Model Coupled with Chemistry (WRF-Chem) atmospheric chemistry model, a parameterization scheme for the radioactive isotope caesium (137Cs), considering processes such as advection, turbulent diffusion, dry deposition, and wet deposition, was constructed, enabling the spatial distribution simulation of the concentration and deposition of 137Cs. The experimental simulation studies were carried out during the high emission period of the Fukushima nuclear accident (from 11 to 17 March 2011). Two sets of comparison experiments, with or without deposition, were designed, the effects of wind field and precipitation on the spatial transport and ground deposition of 137Cs were analyzed, and the influence of wind field and precipitation on 137Cs vertical transport was analyzed in detail. The results indicate that the model can accurately simulate the meteorological and 137Cs variables. On 15 March, 137Cs dispersed towards the Kanto Plain in Japan under the influence of northeastern winds. In comparison to the experiment without deposition, the concentration of 137Cs in the Fukushima area decreased by approximately 286 Bq·m−3 in the deposition experiment. Under the influence of updrafts in the non-deposition experiment, a 137Cs cloud spread upward to a maximum height of 6 km, whereas in the deposition experiment, the highest dispersion of the 137Cs cloud only reach a height of 4 km. Affected by the wind field, dry deposition is mainly distributed in Fukushima, the Kanto Plain, and their eastern ocean areas, with a maximum dry deposition of 5004.5 kBq·m−2. Wet deposition is mainly influenced by the wind field and precipitation, distributed in the surrounding areas of Fukushima, with a maximum wet deposition of 725.3 kBq·m−2. The single-station test results from the deposition experiment were better than those for the non-deposition experiment: the percentage deviations of the Tokyo, Chiba, Maebashi, and Naraha stations decreased by 61%, 69%, 46%, and 51%, respectively, and the percentage root mean square error decreased by 46%, 25%, 38%, and 48%, respectively.

Dynamics of 137Cs content in higher aquatic plants of Kyiv and Kaniv Reservoirs

The study aimed to determine the temporal parameters of 137Cs specific activity in higher aquatic plants of Kyiv and Kaniv reservoirs. Parameters characterizing the dynamics of 137Cs content for hydrophytes (Potamogeton perfoliatus and Ceratophyllum demersum) and helophytes (Phragmites australis and Typha angustifolia) were determined based on the results of 137Cs specific activity determination in the aboveground plant organs. Plant samples were collected in 1989–2021 from a polygonal area in the upper part of Kyiv reservoir (shallow waters near Strakholyssia village) and in 2000–2021 from a polygonal area in the middle part of the Kaniv reservoir (shallow waters near Rzhyschiv and the Borispol islands). A model of specific activity of aquatic organisms was substantiated (or developed) in case of exponential decrease in radionuclide levels in the environment. The main parameter of the model is the period of resulting halving of organism specific activity due to the decrease in radionuclide concentration in water, its irreversible fixation in bottom sediments, and radioactive decay. During 1989–2021, the half-life period of 137Cs specific activity in Potamogeton perfoliatus, Ceratophyllum demersum, and Phragmites australis of Kyiv reservoir was 5.4 years. Two time intervals were identified, characterized by different intensities of radionuclide specific activity decrease. During the periods of 1989–1996 (1998), the specific activity of 137Cs in the studied plant species decreased by half in approximately 2 years. For the time interval of 2011(2012)–2021, the half-life period of 137Cs content in Potamogeton perfoliatus and Ceratophyllum demersum increased on average to 12 years. A tendency towards a slowdown in the rate of specific activity decrease was observed for Phragmites australis. During 1987–1996, the half-life period of maximum 137Cs specific activity in higher aquatic plants of Kaniv reservoir was 2.1 years. Thus, during the first decade after the accident, the rates of 137Cs content decrease in plants of Kyiv and Kaniv reservoirs did not differ. In 2000–2021, the rate of 137Cs specific activity decrease in Potamogeton perfoliatus and Ceratophyllum demersum of Kaniv reservoir corresponded on average to a half-life period of about 20 years. For Phragmites australis and Typha angustifolia, only a tendency to decrease in 137Cs activity was noted, corresponding to a half-life period of about 40 years. Over time, the half-life period of 137Cs specific activity in higher aquatic plants of Kyiv and Kaniv reservoirs increases, which is explained by the slowdown in the rate of decrease in volumetric activity of 137Cs in the waters of the Dnipro and Pripyat rivers. A model of 137Cs specific activity in higher aquatic plants of reservoirs for periods exceeding 20 years after accidental radionuclide entry into ecosystems of large plain reservoirs has been proposed. The parameters of the model describing the dynamics of 137Cs specific activity can be used for predictive assessments of 137Cs content in higher aquatic plants in the event of accidental radionuclide entry into ecosystems of large plain reservoirs.

37 years after the chernobyl: the current radiation status in Kocaeli, Turkey

This study aims to assess the artificial and natural radiation dose levels in certain districts of Kocaeli province within the Marmara region, 37 years after the Chernobyl nuclear accident, and evaluate the current status prior to potential nuclear leakage events from Zaporijya or other nuclear power plants. Radioactive concentrations of 232Th, 238U, 40K and 137Cs were determined using HPGe gamma spectrometry in 26 soil samples collected from the region of interest. The average concentrations were found to be 22.35 Bqkg−1 for 238U, 26.36 Bqkg−1 for 232Th, 368.34 Bqkg−1 for 40K, and 2.44 Bqkg−1 for 137Cs. Furthermore, the study revealed an absorbed dose rate of 41.73 nGyh−1, an annual effective dose equivalent of 51.18 µSvy−1, and an excess lifetime cancer risk of 0.00018.

The current status of natural and artificial radiation in İstanbul 36 years after chernobyl, preceding a potential nuclear threat

In this study, the current status of natural and artificial radioactivity levels in soil samples from the Büyükçekmece and Silivri districts of Istanbul, as well as the Marmara Ereğlisi district in Tekirdağ, has been determined in anticipation of a potential nuclear leakage (e.g. the Zaporizhzhia Nuclear Power Plant). Twenty soil samples were collected from the study area, and the radioactivity concentrations of 226Ra, 232Th, 40K and 137Cs were measured using an HPGe detector. The average concentrations of 226Ra, 232Th, 40K and 137Cs were found to be 26 ± 2, 30 ± 2, 540 ± 29, 0.55 ± 0.07 Bq kg−1, respectively.

Long-term behaviour of Cs-137, Cs-133 and K in beech trees of French forests

In the long-term after atmospheric deposit onto a forest ecosystem, Cs-137 becomes incorporated into the biogeochemical cycle of stable elements and progressively reaches a quasi-equilibrium state. This study aimed at determining to what extent Cs-137 activity distribution in tree vegetation could be predicted from that of stable caesium (Cs-133) and potassium (K), which are known to be stable chemical analogues and competitors for Cs-137 intake in tree organs. Field campaigns that focused on beech trees (Fagus sylvatica L.) were conducted in 2021 in three French forest stands with contrasted characteristics regarding either the contribution of global vs. Chornobyl fallouts, soil or climatic conditions. Decades after Cs-137 fallouts, it was found that more than 80% of the total radioactive inventory in the system remained confined in the top 20 cm mineral layers, while organic layers and beech vegetation (including roots) contributed each to less than 1.5%. The enhanced downward migration of Cs-137 in cambisol than podzol forest sites was presumably due to migration of clay particles and bioturbation. The distribution of Cs-137 and Cs-133 inventories in beech trees was very similar among sites but differed from that of K due a higher accumulation of Cs isotopes in roots (40–50% vs. < 25% for K). The aggregated transfer factor (Tag) of Cs-137 calculated for aerial beech organs were all lower than those reported in literature more than 20 years ago, this suggesting a decrease of bioavailability in soil due to ageing processes. Regarding their variability, Tags were generally lower by a factor 5 at the cambisol site, which was fairly well explained by a much higher value of RIP (radiocesium immobilisation potential). Cs-137 concentrations in trees organs normalized by the soil exchangeable fractions were linearly correlated to those of Cs-133 and the best fit was found for the linear regression model without intercept indicating that no more contribution of the foliar uptake could be observed on long term. Provided that the vertical distribution of caesium concentrations and fine root density are properly measured or estimated, Cs-133 was shown to be a much better proxy than K to estimate the root transfer of Cs-137.

Gross alpha/beta and radionuclide activity concentrations in soil, plant and some fruits around the Tehran Research Reactor

Human activities usually have some contamination as effluents from chemical industries and radionuclides from nuclear reactors. For assessing the probable radioactive contamination in vicinity of Tehran Research Reactor, The gross alpha and beta radioactivity concentrations in soil, pine and cedar leaves and some selected fruits (fig, apple, berry and pomegranate) were investigated using an alpha/beta spectrometer during 2021–2022. Also, the concentrations of artificial and natural radionuclides in samples were investigated by the method of gamma spectroscopy. The gross alpha activity concentrations in soil, pine and cedar leaves and some selected fruits samples are from 0.05 to 0.35 Bq/gr and 0.07–0.31 Bq/gr and 0.04–0.18 Bq/gr, respectively. The gross beta activity concentrations in soil, pine and cedar leaves and some selected fruit samples are from 0.73 to 4.25 Bq/gr and 0.21–3.97 Bq/gr and 1.01–2.71 Bq/gr, respectively. Average activities concentration of natural radionuclide 232Th, 238U and 40K in soil, pine and cedar leaves and some selected fruits are 31.89–16.23–582.73 Bq/kg and 1.84–0.99–84.60 Bq/kg and 1.98–1.09–72.08 Bq/kg respectively. From artificial radionuclides, just 137Cs is recognized in soil sample and the range of 137Cs concentration in surface soils was observed to vary in the range 0.85–2.21 (Bq/kg). The result showed that the Tehran Research Reactor activities not have increased the environmental radioactivity and radiation level in the area.

Determining the depth and rate of soil movement down the soil profile using an environmental tracer: a hillslope scale assessment

Context Soil materials can be delivered to depth from both in situ and ex situ materials. Here, we examine a hillslope in an agricultural environment that has been used for cropping and cattle grazing for over 150 years and a parallel area where cattle have been excluded for approximately 20 years. The exclusion area is a shelterbelt and also provides ecological services. Aims To quantify the depth and rate of down profile soil movement using the environmental tracer 137Cs at points along a hillslope profile. Methods 137Cs concentration is measured to bedrock at regular intervals both inside and outside a fenced of ecological services area pre-drought (2015) and post-drought (2021). In Australia. 137Cs is the by-product of nuclear weapons use and testing from1945 to 1972. Therefore, this places an age constraint on any labelled soil. Key results Results show that soil materials can move down the soil profile to reach bedrock at decadal time scales. An important finding is that materials from the surface can reach depths of up to 80 cm near the hillslope crest and up to 2.2 m at the base of the hillslope. Conclusions This demonstrates a relatively rapid translocation of surface material. Implications The method provides the ability to quantify the rapid movement of soil components and demonstrates the potential for deep sequestration of soil organic carbon. The results demonstrate the potential for soil amendments and agrochemicals to be rapidly transported to depth. The findings suggest that cattle exclusion has no impact on the movement of soil materials down the profile over the 20-year exclusion period.

Uptake from water and depuration of 137Cs and 90Sr by silver Prussian carp (Carassius gibelio)

To follow up field observations in the Chornobyl Exclusion Zone (ChEZ), a series of controlled model aquarium experiments were conducted to determine the uptake and depuration rates of 137Cs and 90Sr in silver Prussian carp (Carassius gibelio) in fresh water, varying in temperature from 5 to 27 °C, with daily feeding rates of 0–1.5 % fish weight day−1.In the present study, the 137Cs uptake rates in muscle tissues directly from water, 0.05–0.09 day−1 at temperatures of 5–27 °C, were significantly lower than previously reported for fish fed under natural conditions in contaminated lakes within the ChEZ. The rate of 90Sr uptake in bone tissues of silver Prussian carp varied from 0.055 day−1 at a water temperature of 5 °C and feeding rates ≤0.15 % fish weight day−1 to 1.5 ± 0.2 day−1 at a temperature of 27 ± 1 °С and at the highest tested feeding rate of 1.5 % day−1.The rate of decrease of 137Cs concentration in muscle tissues was kb = 0.0028 ± 0.0004 day−1 (T1/2 = 248 ± 35 days) at the lowest water temperature tested (5 °С). At water temperatures between 13 and 26 °С and a feeding rate of 0.15 % day−1, the rate increased to kb = 0.0071–0.0092 day−1 (T1/2 = 75–99 days).The rates of decrease of 90Sr activity concentration in bone tissues at water temperatures between 22 and 25 °С and a feeding rate of 0.5 % day−1 were kb=0.004–0.0014 day−1, and the associated biological half-life T1/2 ranged 50–160 days, respectively. The present work supported conclusions related to the main pathways of 137Cs and 90Sr uptake by silver Prussian carp, and demonstrated the usefulness of combining field and laboratory uptake and depuration experiments.

Caesium-137 in the muscles of game animals in 2015-2022 - levels and time trend.

Radioactive caesium-137 occurring in the environment may be taken up by plants and animals and pose a trophic threat to humans. Game animals living in forest ecosystems are very good bioindicators of the level of environmental contamination by ionising radiation. The main species measurably exposed to caesium-137 are the wild boar (Sus scrofa), the roe deer (Capreolus capreolus), and the red deer (Cervus elaphus). The study determined the levels of Cs-137 in muscle samples of these game animals in 2015-2022. Using gamma radiation spectrometry, 858 samples of game animal muscle tissue were examined: 508 wild boar, 145 roe deer and 205 red deer samples. Concentrations of Cs-137 varied widely (from minimum detectable activity (MDA) values to over 4,000 Bq/kg). In 63.4% of cases, the obtained concentrations exceeded the MDA. The permissible limit (600 Bq/kg for food) was exceeded in nine wild boar muscle samples, whereas it was not even exceeded once in roe or red deer muscle. The average concentration in wild boar was three times higher than in roe and red deer and amounted to 42.84 Bq/kg. The highest concentration of Cs-137 in wild boar muscle was 4,195 ± 372.0 Bq/kg, in roe deer muscle it was 111.5 ± 12.50 Bq/kg, and in red deer muscle was 86.70 ± 3.470 Bq/kg. The seven years' data indicate that wild boar absorb the most caesium-137 among game animals. The concentrations of Cs-137 in the muscle of game animals in the years 2015-2022 were at a nearly constant level, a very slow diminution being noticeable over time in roe and red deer muscle.

Lagrangian and Eulerian approach to predict the movement of radionuclides in selected potential sites in Malaysia during the monsoon period

In computing the movement of particles through the fluid, three types of dispersion models are used which are Gaussian plume models, Lagrangian puff models, and small-scale numerical models. Lagrangian particle dispersion models are increasingly used for nuclear applications. In this study, the usage of the Lagrangian model is implemented in a Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) which combines with the Eulerian model to predict the movement of radionuclides from the simulated nuclear power plant accident in selected locations in Malaysia. These include nuclear risk studies in these areas, emergency response systems, and source term analyses. This study aims to compare the risk from the dispersion of 137Cs from a simulated Nuclear Power Plant (NPP) at Mukah and Tasik Kenyir during the Northeast monsoon (8th October 2022) and Southeast monsoon (16th May 2022). The HYSPLIT model was set up based on the meteorological data during both monsoon periods and was simulated for 5 days. The outcomes revealed that the concentration of 137Cs is higher at Tasik Kenyir compared to Mukah for both during the Northeast monsoon period (3.5 x 107 Bq/m2) while for Southwest monsoon, the result is vice versa where the concentration of 137Cs at Mukah is (2.2 x 107Bq/m2). The activity concentration is then converted into rate effective dose measurement and compared with the limit suggested by ICRP which is 1 Sv per year. It is concluded that Tasik Kenyir is a more suitable location to build NPP compared to Mukah as the movement of radionuclides was dispersed to the location that contained less population.

Associations between maternal exposure to multiple metals and metalloids and blood pressure in preschool children: A mixture-based approach

BackgroundExposure to metals during pregnancy can potentially influence blood pressure (BP) in children, but few studies have examined the mixed effects of prenatal metal exposure on childhood BP. We aimed to assess the individual and combined effects of prenatal metal and metalloid exposure on BP in preschool children. MethodsA total of 217 mother–child pairs were selected from the Zhuang Birth Cohort in Guangxi, China. The maternal plasma concentrations of 20 metals [e.g. lead (Pb), rubidium (Rb), cesium (Cs), and zinc (Zn)] in early pregnancy were measured by inductively coupled plasmamass spectrometry. Childhood BP was measured in August 2021. The effects of prenatal metal exposure on childhood BP were explored by generalized linear models, restricted cubic spline and Bayesian kernel machine regression (BKMR) models. ResultsIn total children, each unit increase in the log10-transformed maternal Rb concentration was associated with a 10.82-mmHg decrease (95% CI: −19.40, −2.24) in childhood diastolic BP (DBP), and each unit increase in the log10-transformed maternal Cs and Zn concentrations was associated with a 9.67-mmHg (95% CI: −16.72, −2.61) and 4.37-mmHg (95% CI: −8.68, −0.062) decrease in childhood pulse pressure (PP), respectively. The log10-transformed Rb and Cs concentrations were linearly related to DBP (P nonlinear=0.603) and PP (P nonlinear=0.962), respectively. Furthermore, an inverse association was observed between the log10-transformed Cs concentration and PP (β =-12.18; 95% CI: −22.82, −1.54) in girls, and between the log10-transformed Rb concentration and DBP (β =-12.54; 95% CI: −23.87, −1.21) in boys, while there was an increasing association between the log10-transformed Pb concentration and DBP there was an increasing in boys (β =6.06; 95% CI: 0.36, 11.77). Additionally, a U-shaped relationship was observed between the log10-transformed Pb concentration and SBP (P nonlinear=0.015) and DBP (P nonlinear=0.041) in boys. Although there was no statistically signiffcant difference, there was an inverse trend in the combined effect of maternal metal mixture exposure on childhood BP among both the total children and girls in BKMR. ConclusionsPrenatal exposure to both individual and mixtures of metals and metalloids influences BP in preschool children, potentially leading to nonlinear and sex-specific effects.

Unravelling the effects of magmatic fractionation, fluid phase separation and dilution on the composition of magmatic-hydrothermal fluids of the Cornubian Batholith (SW England)

The compositional evolution of magmatic-hydrothermal fluids from the SnW mineralized Cornubian batholith was investigated via in situ fluid inclusion LA-ICP-MS microanalysis and reveals a large degree of variation between intrusive stages and at the sample scale, with complexities due to superposition of several mechanisms affecting fluids chemistry during the protracted evolution of the batholith. Despite large ranges of salinities (from <1 wt% to 48 wt% NaCleq.), the effects of individual processes such as magmatic differentiation, fluid saturation and boiling, fluid mixing and dilution can all be discerned on the basis of fluid inclusion trace element geochemistry combined with detailed petrography and microthermometry.In all samples, different fluid types (aqueous liquid-rich, vapor-rich and brine inclusions) were identified in variable proportions and microthermometry revealed complex temporal trends. Granite-related samples from the G5 intrusive stage are characterized by intermediate density fluids undergoing magmatic fractionation under pressure conditions above 1.5 kbar, indicated by successively decreasing fluid salinities with concomitant increases in Li, B, Rb and Cs concentrations. The latter two elements later strongly partitioned in the brine phase upon boiling, together with most of the other Cl-complexing elements (e.g., Fe, Mn, Pb, Zn). Those brines subsequently underwent progressive dilution with meteoric waters that caused a decrease in the concentration of all elements (besides B) and homogenization temperatures. In G3 granite from Dartmoor, on the other hand, brine inclusions represent the earliest fluid type while intermediate density fluids are absent, and a large salinity range in the fluid inclusion record associated with a decrease in homogenization temperatures represents their progressive dilution with meteoric fluid. The lack of intermediate density fluids at Dartmoor indicates fluid exsolution at relatively low pressures resulting in immediate phase separation into brine and vapor.All studied samples associated with ore mineralization display only the trend of dilution of high-salinity magmatic fluids. Their transition metal contents (e.g. Fe, Mn, Pb and Zn) show the expected positive correlation with salinity of the fluids. Conversely, the compositional trends observed for Sn and particularly W are more enigmatic, as they do not appear to significantly fractionate during most of the physicochemical processes outlined above and appear to be unrelated to fluid salinity, opposite of what would be expected for Sn as it is dominantly transported in Cl-complexes.This study highlights the key advantages of high-resolution geochemical fluid inclusion studies in discerning a variety of magmatic and post-magmatic processes in fluids in comparison to bulk fluid inclusion techniques or more simplistic fluid inclusions studies which might overlook important aspects of the typically complex history of fluids evolution in magmatic-hydrothermal systems.