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The conventional measuring methods (runoff plots and soil morphological comparison) and models (WaTEM/SEDEM and regional model of Russian State Hydrological Institute (SHI)) were tested with regard to the Southern Cis-Ural region of Russia, along with data from rainfall simulation for assessing soil erosion. Compared with conventional methods, which require long-running field observations, using erosion models and rainfall simulation is less time-consuming and is found to be fairly accurate for assessing long-term average rates of soil erosion and deposition. In this context, 137Cs can also be used as a marker of soil redistribution on the slope. The data of soil loss and sedimentation rates obtained by using conventional measuring methods were in agreement with the data based on the used contemporary modeling approaches. According to the erosion model calculations and data on the fallout of radionuclides in the Southern Cis-Ural (54°50–25′ N and 55°44–50′ E), the average long-term annual soil losses were ~1.3 t·ha−1 yr−1 in moderate (5°) arable slopes and ~0.2 t·ha−1 yr−1 in meadows. In forests, surface erosion is negligible, or its rates are similar to the rate of soil formation of clay–illuvial chernozems. The rates of soil erosion and sediment deposition on the arable land obtained using different methods were found to be very close. All the methods, including the WaTEM/SEDEM, allowed us to measure both soil erosion and intra-slope sedimentation. The regional SHI model fairly accurately assesses soil erosion in the years when erosion events occurred; however, soil erosion as a result of snowmelt did not occur every year, which should be taken into account when modeling. The concentrations of 137Cs in the topsoil layer (0–20 cm) varied from 0.9 to 9.8 Bq·kg−1, and the 137Cs inventories were 1.6–5.1 kBq·m−2, with the highest values found under the forest. The air dose rate in the forest was higher than in open areas and above the average of 0.12 μSv·h−1 on the slope (0.1 μSv·h−1 in the meadow and 0.08 μSv·h−1 on the arable land), with the value increasing from the watershed to the lower part of the slope in all the areas. The γ-background level in the studied ecosystems did not exceed the maximum permissible levels. [ABSTRACT FROM AUTHOR]

Andosols are the soil type that potentially has the highest radiocesium (RCs) transfer risk due to their deficiency in micaceous minerals (micas) that can strongly retain RCs in their interlayer sites. However, an exogeneous source of micas as a component of Asian dust may have contributed largely to increase the RCs retention ability for Andosols in Tohoku Region, Japan. We investigated 29 pasture soils with andic soil properties that were collected at various places across this region to clarify the provenance of micas whether they originated from Asian dust or local lithological materials. Mica content in bulk size fraction (<2.0 mm) positively and strongly correlated with the factor related to felsic elemental composition obtained by principal component analysis (r = 0.90, p < 0.01). Fine micas in the <20 µm fraction (Mica<20 µm) accounted for a large fraction (72 ± 16%) of the total mica contents and positively correlated with the content of fine quartz derived from Asian dust (Qzad_<20 µm) (r = 0.86, p < 0.01), which were distinguished from fine quartz derived from igneous bedrock materials (Qzig_<20 µm) by using the δ18O values for quartz isolated from the <20 µm fraction. Furthermore, Mica<20 µm correlated positively with radiocesium interception potential (RIP) of this fraction. These results for the first time demonstrated the importance of Asian-dust-derived micas relative to those from another local sources on the RCs retention abilities in Andosols in Tohoku, Japan. [ABSTRACT FROM AUTHOR]

Abstract Hilly and mountainous regions are significantly impacted by soil erosion, primarily due to rainfall-runoff processes occurring on the hillslope scale. Assessing soil erosion is crucial for quantifying the loss of soil carbon and nutrients, which diminishes the potential of soil ecosystem services and is critical for mitigating the impacts of climate change on food security. However, the Himalayan landscape poses serious challenges for assessing soil erosion due to its steep and rugged terrain, which hinders the use of conventional and modelling methods. The fallout radionuclide—137Cs has been extensively utilized as an environmental marker for investigating soil redistribution processes. Despite its potential, there is a notable lack of 137Cs-based soil erosion studies in the Himalayan region. In this context, we assessed the applicability of the fallout radionuclide—137Cs method in quantifying soil erosion rates and identifying erosion hotspots on two hillslopes of the Higher Himalayas. On the hillslope scale, we observed that soil erosion rates vary based on slope gradient and land use/land cover. Forested areas exhibited the lowest soil erosion rates compared to cultivated areas, while flat hillslope positions experienced lower erosion rates than steeper positions. The average net erosion rate for the Harsil hillslope varied among different hillslope positions, ranging from – 2.9 to – 15.6 t ha−1 yr−1. Similarly, in the Gangnani hillslope, the net erosion rates varied across different positions, ranging from – 5.6 to – 39 t ha−1 yr−1. Our findings confirm that the middle and lower hillslope positions are the most critical source areas with higher soil erosion rates, while hillslope positions with forest cover demonstrate the lowest erosion rates, identified as helpful in controlling soil erosion. The study has demonstrated the applicability of FRN as a soil erosion measurement method in the complex, rugged, and steep terrain of the Himalayas, highlighting the need for targeted conservation efforts to mitigate soil erosion and preserve ecosystem integrity.

Hilly and mountainous regions are significantly impacted by soil erosion, primarily due to rainfall-runoff processes occurring on the hillslope scale. Assessing soil erosion is crucial for quantifying the loss of soil carbon and nutrients, which diminishes the potential of soil ecosystem services and is critical for mitigating the impacts of climate change on food security. However, the Himalayan landscape poses serious challenges for assessing soil erosion due to its steep and rugged terrain, which hinders the use of conventional and modelling methods. The fallout radionuclide—137Cs has been extensively utilized as an environmental marker for investigating soil redistribution processes. Despite its potential, there is a notable lack of 137Cs-based soil erosion studies in the Himalayan region. In this context, we assessed the applicability of the fallout radionuclide—137Cs method in quantifying soil erosion rates and identifying erosion hotspots on two hillslopes of the Higher Himalayas. On the hillslope scale, we observed that soil erosion rates vary based on slope gradient and land use/land cover. Forested areas exhibited the lowest soil erosion rates compared to cultivated areas, while flat hillslope positions experienced lower erosion rates than steeper positions. The average net erosion rate for the Harsil hillslope varied among different hillslope positions, ranging from – 2.9 to – 15.6 t ha−1 yr−1. Similarly, in the Gangnani hillslope, the net erosion rates varied across different positions, ranging from – 5.6 to – 39 t ha−1 yr−1. Our findings confirm that the middle and lower hillslope positions are the most critical source areas with higher soil erosion rates, while hillslope positions with forest cover demonstrate the lowest erosion rates, identified as helpful in controlling soil erosion. The study has demonstrated the applicability of FRN as a soil erosion measurement method in the complex, rugged, and steep terrain of the Himalayas, highlighting the need for targeted conservation efforts to mitigate soil erosion and preserve ecosystem integrity. [ABSTRACT FROM AUTHOR]

Radioactively contaminated soil from the Fukushima Daiichi nuclear power station accident in 2011 is required by law to be finally disposed of outside Fukushima Prefecture by 2045. To gain public acceptance of this policy, it is essential to promote understanding and nationwide discussion. We conducted a web-based survey of 2000 people in Japan to examine public attitudes toward final disposal of the contaminated soil outside Fukushima Prefecture. Results show that policy approval was negatively correlated with perceived risk of a final disposal site, sense of inequity associated with building a final disposal site near residential areas, and values that are absolutely non-negotiable or protected from trade-offs with other values (protected values). Policy approval was positively correlated with high levels of interest in the Fukushima accident and subjective knowledge of decontamination and the policy. Respondents' comments and opinions about the policy indicated that respondents who approved of the policy accepted burden sharing, while those who disapproved were unconvinced by the rationale behind disposal outside Fukushima Prefecture and were dissatisfied by the lack of information disclosure and transparency. While the government's efforts to disseminate information about the current status and future of Fukushima have been effective to a certain extent, they are insufficient to achieve widespread public understanding of the policy. Our results indicate that attention needs to be paid to procedural fairness and explanations of risks. [ABSTRACT FROM AUTHOR]

The conventional measuring methods (runoff plots and soil morphological comparison) and models (WaTEM/SEDEM and regional model of Russian State Hydrological Institute (SHI)) were tested with regard to the Southern Cis-Ural region of Russia, along with data from rainfall simulation for assessing soil erosion. Compared with conventional methods, which require long-running field observations, using erosion models and rainfall simulation is less time-consuming and is found to be fairly accurate for assessing long-term average rates of soil erosion and deposition. In this context, 137Cs can also be used as a marker of soil redistribution on the slope. The data of soil loss and sedimentation rates obtained by using conventional measuring methods were in agreement with the data based on the used contemporary modeling approaches. According to the erosion model calculations and data on the fallout of radionuclides in the Southern Cis-Ural (54°50–25′ N and 55°44–50′ E), the average long-term annual soil losses were ~1.3 t·ha−1 yr−1 in moderate (5°) arable slopes and ~0.2 t·ha−1 yr−1 in meadows. In forests, surface erosion is negligible, or its rates are similar to the rate of soil formation of clay–illuvial chernozems. The rates of soil erosion and sediment deposition on the arable land obtained using different methods were found to be very close. All the methods, including the WaTEM/SEDEM, allowed us to measure both soil erosion and intra-slope sedimentation. The regional SHI model fairly accurately assesses soil erosion in the years when erosion events occurred; however, soil erosion as a result of snowmelt did not occur every year, which should be taken into account when modeling. The concentrations of 137Cs in the topsoil layer (0–20 cm) varied from 0.9 to 9.8 Bq·kg−1, and the 137Cs inventories were 1.6–5.1 kBq·m−2, with the highest values found under the forest. The air dose rate in the forest was higher than in open areas and above the average of 0.12 μSv·h−1 on the slope (0.1 μSv·h−1 in the meadow and 0.08 μSv·h−1 on the arable land), with the value increasing from the watershed to the lower part of the slope in all the areas. The γ-background level in the studied ecosystems did not exceed the maximum permissible levels.

The paper presents data on the spatial distribution of the active concentration of natural (232Th, 226Ra, and 40K) and anthropogenic (137Cs) radionuclides in the surface layer of bottom sediments in Chaun Bay of the East Siberian Sea. The measured active concentration of 232Th and 226Ra was typical of bottom sediments of the Arctic coastal shelf zone and corresponded to the global level. The level of 137Cs activity in bottom sediments showed the absence of local sources of anthropogenic pollution in Chaun Bay, while the mean 40K activity concentration was 1.8 times higher than the global. The results of statistical analysis of the data obtained showed that the dynamics of river runoff, thermal abrasion, and currents, as well as aeolian and ice transport of sedimentary matter, were the main factors that determined the differences in the behavior of the studied radionuclides in the surface bottom sediments of Chaun Bay. [ABSTRACT FROM AUTHOR]

In urban ecosystems to the west of the Elektrostal Heavy Machinery Plant, six years after the radiation incident, local sites with a total area of 0.2 km2 with an increased equivalent dose rate of γ radiation of 0.15–0.40 μSv/h and a high specific activity of 137Cs reaching 8328–8740 Bq/kg in the upper soil horizons were identified. Statistically significant direct correlations were noted between the specific activity of 137Cs in the layer of 0–10 cm of soil and the equivalent dose rate of γ radiation at the surface and height of one meter. The types of vertical distribution of 137Cs in soils of polluted urban ecosystems, including those on which earth decontamination works were carried out, have been determined. The calculated 137Cs transfer coefficients increase in the series of trees Salix alba < Sórbus aucupária < Ácer platanoídes < Malus domestica < Alnus incana < Ácernegúndo; and grassy vegetation Týpha angustifólia < Artemísia vulgáris < Tussilágo fárfara < Cirsium arvense < Urtíca dióica. [ABSTRACT FROM AUTHOR]

In surrounding areas influenced by the Fukushima Dai-ichi Nuclear Power Plant accident, the radiocesium uptake by crops was evaluated based on soil exchangeable K. As risk evaluation does not function effectively in several fields, K buffering was characterized using quantity/intensity (Q/I) relationship analysis to evaluate the availability of exchangeable K. The results of the analysis clearly explain the difficulty in the risk evaluation: i) difficulty in increasing exchangeable K, owing to retention as non-exchangeable K by vermiculite; ii) difficulty in retaining exchangeable K due to low K buffering capacity, reflecting the lack of K-selective clay minerals; and iii) difficulty in increasing soil solution K intensity due to high K buffering capacity, reflecting the abundance of K-selective clay minerals. Among the parameters calculated from the Q/I relationship analysis, β values, corresponding to the retention rate of loaded K to the soil, for total K (βt), exchangeable K (βe), and non-exchangeable K (βn) would be useful as simple indicators of soils with a predicament in the risk evaluation of radiocesium uptake by crops through exchangeable K. These soils showed distinctively low βt values (0.18 or lower), high βe value (0.37 or higher), or high βn/βt ratio (0.53 or higher). [ABSTRACT FROM AUTHOR]

Thermochemical conversion of garden waste to biochar was carried out to prepare a green adsorbent for the removal of Cs, Cu, Ni, and Pb, which was characterized by XPS, SEM–EDX, and FT-IR analyses. The biocharˊs adsorption capacity was 20.5(Cs), 25.2(Cu), 12.4(Ni), and 45.9(Pb) mg g−1 and demonstrated satisfactory performance for different pH values. The kinetics data evaluation revealed that besides chemisorption, intraparticle diffusion contributes to metal removal. Moreover, the physical and structural properties of biochar play an important role in adsorption. Results indicate the suitability of using GW biochar as an alternative sorbent for both radionuclides and metal extraction. [ABSTRACT FROM AUTHOR]

The vertical distribution of the anthropogenic radionuclide Cs-137 in the Scots pine (Pinus sylvestris L.) bark was studied in two model trees in the radioactive contamination zone of the Bryansk region. Each tree was divided into 10-cm bars from the trunk base to a length of 17 m, and the bark with the bast was separated from each bar to obtain a separate sample. In addition to Cs-137, the natural radionuclide K-40 was measured in the bark of model tree 2 from the trunk base to a 6.5-m length. Specific activities of Cs-137 and K-40 were measured by γ-ray spectrometry. The vertical distribution of Cs-137 in the bark was for the first time observed to have a wave-like pattern with a period of approximately 1 m. The K-40 distribution showed a similar oscillatory pattern, consistent with a similar mechanism responsible for potassium and cesium behavior in woody plants. The correlation coefficient between specific activities of Cs-137 in model trees 1 and 2 was 0.80; the correlation coefficient between Cs-137 and K-40 activities in model tree 2 was 0.45. Cs-137 was assumed to provide a radiotracer to assess the intake and distribution of chemical elements in Scotch pine tissues. The oscillatory pattern observed for the vertical distributions of cesium and potassium in the pine bark has not been described in the available literature before. [ABSTRACT FROM AUTHOR]

Removing the hazardous and unstable radioactive isotopes has been considered an arduous task, though they are in minimal concentrations. Cesium-137 (137Cs+) is a primary fission product produced by nuclear processes. Even at low concentrations, such radioactive material is a menacing source of contaminants for the environment. The current study aims to separate 137Cs+ from a real contaminated aqueous solution via an ion exchange mechanism using ammonium molybdophosphate–polyacrylonitrile (AMP-PAN) resin loaded in an extraction chromatographic column that possesses considerable selectivity toward cesium ion (Cs+) due to the specific ion exchange between 137Cs+ and NH4+. Additionally, the proposed interaction mechanism between 137Cs+ with APM-PAN resin has been illustrated in this study. The results disclosed that the optimum efficient removal of 137Cs+ (91.188%) was obtained by the AMP-PAN resin using 2 g·L−1, while the distribution adsorption coefficient (129.359 mL·g−1) was at pH 6. The isothermal adsorption process was testified through the Langmuir and Freundlich models. The estimated maximum adsorption capacity reached 140.81 ± 21.3 mg·g−1 for the Freundlich isotherm adsorption model. Finally, AMP-PAN resin could eliminate 137Cs+ from water effectively through adsorption. [ABSTRACT FROM AUTHOR]

Potassium copper hexacyanoferrate (II)–clinoptilolite (KCuHCF–CL) composite was prepared for cesium removal in this study. The composite was characterized by FT-IR, SEM and TGA analyses. The effects of several factors such as contact time, temperature, concentration, pH and competitive ions were investigated. The prepared sorbents were better fitted to the pseudo-second order kinetic model and Langmuir isotherm. The maximum adsorption capacity (qm) was 1.001 mmol g−1 at 60 °C. The adsorption process onto the composite was thermodynamically feasible and endothermic. Cs adsorption capacity was highest in the pH range of 7 – 8, while the acidic and alkali conditions resulted in the decrease of adsorption ability. To examine the practical applicability, Cs removal test from the simulated wastewater was carried out. KCuHCF KCuHCF–CL composite shows the high selectivity, sufficient capacity and good applicability. [ABSTRACT FROM AUTHOR]

The accident at the Chornobyl nuclear power plant was one of the most serious nuclear incidents in human history. A radioactive plume covered a whole strip of northeastern Europe. The consequences of this catastrophe are still being felt, both in Ukraine and around the world. The article is devoted to the assessment of the consequences of radiocesium contamination of agricultural lands and irrigated waters during a possible accident at the Zaporizhzhia NPP and the associated Cs137 contamination of sunflower products in the Zaporizhzhia region. The studies were carried out using a dynamic mathematical model for the formation of radionuclide activity in the "water-soilplant-product" system, ECOSIS-87 (Ecoplant). The article presents the results of studies of possible contamination of the environment by radiocesium according the Chornobyl NPP-86 scenario and sunflower production by the method of mathematical dynamic modeling. The calculations were carried out on the basis of the results of an agrochemical and agroecological survey of the state of soils in Ukraine and the Dnipro cascade of reservoirs. If an explosion occurs at the Zaporizhzhia NPP, the power of which will be equal to the Chornobyl NPP, then 100,000 hectares of agricultural land in the region will be taken out of the agricultural production of the Zaporizhzhia region. On agricultural lands where soil contamination with radiocaesium will be more than 5 Ci/km2, and the concentration in irrigated waters will reach 2 Bq/dm3, sunflower, which was grown for seeds to produce oil will need to be replaced with an industrial crop, which will also lead to loss of seed yield sunflower. Crop losses will lead to a decrease in the volume of sunflower oil. It should also be taken into account that the purification of soil and water does not occur in one year. At least in 5 years the situation will begin to improve. [ABSTRACT FROM AUTHOR]

Subtropical mode water (STMW) plays a pivotal role in material exchange and influences marine ecosystems in the shallow layers of the western Pacific boundary current area (WPBCA, including the Kuroshio and its adjacent marginal seas), one of the typical western boundary areas in the global ocean. However, since the Kuroshio with high velocity prevents direct intrusion of STMW into the WPBCA, the STMW could only be transported into the WPBCA from the upstream and/or source Kuroshio region. In the region, water mixing blurs the "mode" of STMW and limits its observation. In this study, we measured 137Cs in the WPBCA, and identified the distribution of STMW‐derived water (STMW*) in a certain layer (σθ ∼ 25.2–25.8 kg m−3). In this layer, two different mixing strengths were quantified during the advection of STMW* from the North Pacific to the WPBCA. Quantification based on 137Cs, rare earth elements, temperature, and salinity indicated a significant decrease in the STMW* signature (<50%) in the layer of Luzon Strait, confirming strong vertical mixing due to topographic constraint. In contrast, in the same layer of Tsushima Strait, where nutrients accounted for 15.3% of the total nutrient flux to the Sea of Japan, 57% ± 20% of the water comes from the STMW* of subtropical gyre, indicating weak mixing during the long‐path transport. Quantifying the contribution of subsurface nutrient‐rich water in the subtropical gyre to shallower layers of WPBCA, using direct measured chemical tracers, could be extended to other areas and further to couple with ecosystem models. Plain Language Summary: Material circulation in the western Pacific boundary current area (WPBCA) can be promoted by water originated from subtropical mode water (STMW), which rises with the terrain and stays close to the euphotic layer, contributing to CO2 adsorption during primary production. However, the "mode" of STMW blurs due to water mixing, limiting observations of STMW in the WPBCA. In this study, we provide direct evidence of STMW‐derived water (STMW*) in the WPBCA using total 137Cs activity concentration (mainly from the Fukushima Daiichi Nuclear Power Plant accident). We also quantify for the first time the impact of strong and weak vertical mixing intensities on its distribution. With strong vertical mixing in the Luzon Strait, less than half of STMW* was retained in the layer with σθ of 25.2–25.8 kg m−3. On the other hand, the large remaining rate of STMW* in the same layer of Tsushima Strait implies that this part of STMW* experiences little vertical mixing, explaining high nutrient flux to the Sea of Japan. Quantifying water mixing and material transport by integrated information of chemical tracers would provide valuable data for ecosystem models, and this approach could be further extended to other boundary sea areas. Key Points: Direct evidence of Subtropical Mode Water‐derived water (STMW*) in the western Pacific boundary current area was provided by 137CsAnalyses with 137Cs and rare earth elements indicated a significant decrease in the STMW* signature (<50%) with strong vertical mixingFifty‐seven percent of the STMW* of Tsushima Strait is from subtropical gyre, explaining 8.7% of the dissolved inorganic nitrogen flux to the Sea of Japan [ABSTRACT FROM AUTHOR]

Large amounts of Cesium-137 (137Cs, physical half-life ca. 30 years) were released into the environment from the 2011 Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in Japan. Initially contaminants from the accident were deposited on the surface soil layers in terrestrial ecosystems, but over time vertical migration of 137Cs has occurred, with most 137Cs now distributed a few centimeters below the soil surface. Wild boar (Sus scrofa) rooting likely alters the distribution of contaminants in soil profiles. Such impacts may be particularly pronounced in areas contaminated from the FDNPP accident, given the increase in abundance of wild boar in these areas. Our objective was to determine whether rooting by wild boar alters the distribution of 137Cs contamination within soil profiles through collection of soil cores from control sites and two different types of rooting samples, “new depressions” and “old depressions” within the difficult-to-return zone surrounding the FDNPP. The 137Cs ratio [activity concentration of 137Cs at each depth / the maximum activity concentration of 137Cs in each core sample] rapidly decreased after reaching a peak at the control sites. However, the 137Cs ratio at all rooted sites decreased more slowly, and 137Cs was distributed deeper into the soil layers than control sites, across both new and old rooting sites. Moreover, the 137Cs soil profiles varied greatly among core samples and sampling sites. These results demonstrate that soil disturbance from wild boar rooting can directly influence the distribution of contaminants within soil profiles. However, the extent to which deeper layers are affected by contamination depends on the unique characteristics (i.e., depth of rooting) of each wild boar rooting disturbance. Further studies are needed to examine the effects of long-term rooting on the alteration of 137Cs in soil profiles.

Wild European perch (Perca fluviatilis) is one of the most important freshwater fish species, in Sweden, due to its widespread and his value for recreational fishing. Little it is known regarding the biodistribution of naturally occurring radionuclides such as 238U, 234U, 226Ra, 210Po in perch. Therefore, in this study, perches from five lakes located in different counties in Sweden were collected to investigate the biodistribution of 238U, 234U, 226Ra, 210Po and 137Cs in organs and tissues of perch as well as their radiological impact. The results showed that uranium radionuclides ranged between 0.1 and 6 Bq/kg with an average value of 1.1 ± 1.5 Bq/kg. 226Ra varied from 0.4 to 8 Bq/kg with a mean concentration of 1.7 ± 1.9 Bq/kg. The ranged of 210Po was 0.5 – 250 Bq/kg, with an average value of 24 ± 52 Bq/kg. On the other hand, the highest activity concentration of 137Cs, 151 ± 1 Bq/kg, was detected in muscle samples of perch from Redsjösjön lake. For uranium radionuclides and 226Ra uptake from water is the main source whereas for 210Po and 137Cs the uptake is controlled by the perch diet. Regarding naturally occurring radionuclides, the perch tended to accumulated uranium radionuclides in fins, gills, and skin; 226Ra in bones, fins and skin and 210Po in the organs linked to digestive system. Finally, in case of consumption, it is advised the consumption of skinned fillets of perch due to the higher bioaccumulation of the radionuclides investigated in the skin and scales.

This study was conducted to elucidate the spatial and size variations, and food-web transfer of 137Cs in freshwater fish in the upper reaches of the Ukedo River system, a highly contaminated river system flowing through the Fukushima evacuation zone. Fish collection and environmental surveys were conducted in the summer of 2020 at five forest rivers and at the Ogaki Dam reservoir (an artificial lake) with different air dose rates (mean 0.20–3.32 μSv/h). From the river sites, two salmonid species (masu salmon and white-spotted charr) were sampled, with masu salmon generally exhibiting higher 137Cs concentrations, ranging widely (10.6 Bq/kg-wet to 13.0 kBq/kg-wet) depending on the fish size (size effect) and site. The 137Cs concentrations in masu salmon were explained by the air dose rates, 137Cs concentrations in water, sediments (excluding the lake site), and primary producers, with site-specific variations. In the rivers, masu salmon (fluvial type with parr marks) mainly fed on terrestrial insects with higher 137Cs concentrations compared with those of aquatic insects, indicating that 137Cs was transferred mainly to fish through the allochthonous forest food-web during summer. In the lake, masu salmon (lake-run type with larger size and silvery body coloration) mainly preyed on smaller fish with lower 137Cs concentrations, demonstrating that 137Cs is transferred to fish through the autochthonous lake food-web with biomagnification. Differences in 137Cs concentrations among masu salmon (mean 441 Bq/kg-wet) and other fish species (mean 74.8 Bq/kg-wet to 2.35 kBq/kg-wet) were also found in the lake. The distinct 137Cs transfers to river and lake fish were supported by stable isotope analysis: δ15N and δ13C values enriched stepwisely through the food-webs were, respectively, higher and lower in the lake. Our results obtained using multiple approaches clearly revealed the distinct food-web transfer of 137Cs in river and lake ecosystems. These findings can contribute to prediction of radioactive contamination in freshwater fish in the Fukushima evacuation zone. • We examined 137Cs variations in fish of the Fukushima evacuation zone. • The river system fish 137Cs concentrations differed by three orders of magnitude. • Masu salmon fed mainly on terrestrial insects in rivers and small fish in a lake. • Rivers showed 137Cs biodilution, but biomagnification was found in the lake. • CN isotopes reflected the distinct food-web 137Cs transfers to river and lake fish. [ABSTRACT FROM AUTHOR]

Sediment that has deposited after the flood generated by the 2019 typhoon (referred to as Flood Sediment, FS) was collected along two rivers in eastern Fukushima Prefecture, Japan to determine the total and exchangeable radiocesium ($^{137}\mathrm{Cs}$), and acid-extractable potassium (K) contents. Then, these FS parameters were compared with those of decontaminated soils (DS) in nearby agricultural fields to discuss the potential transfer risk of $^{137}\mathrm{Cs}$ from rivers to nearby remediated soils. While FS had about four times higher total $^{137}\mathrm{Cs}$ content, it showed a three-times lower exchangeable $^{137}\mathrm{Cs}$ content than DS. Furthermore, acid-extractable K referred to as non-exchangeable K (Nex-K) content was high enough to restrict $^{137}\mathrm{Cs}$ transfer from soil to crops for both FS and DS. From these comparisons, we concluded that deposition of FS onto DS may not increase the transfer of $^{137}\mathrm{Cs}$ from soil to crops.

Abstract The deposition of insoluble radiocesium-bearing microparticles (CsMPs), which were released from the Fukushima Daiichi Nuclear Power Plant (F1NPP) accident in March 2011, has resulted in the widespread contamination of eastern Japan. Obviously, these deposited insoluble CsMPs may become the secondary contamination sources by atmospheric migration or other environmental transferring process; however, the understanding of the transport mechanism remains non-elucidation, and the relevant evidence has not been directly provided. This study, for the first time, provides the direct evidence for the resuspension of these insoluble CsMPs to the atmosphere from (1) proximity of 137Cs radioactivity and resemblance of the morphology and the elemental compositions of CsMPs in the samples of soil and aerosol derived from the same sampling site, (2) the special characteristics of the resuspended CsMPs of which the ratios of Na/Si, K/Si and/or Cs/Si were smaller than those from the initially released CsMPs collected at either long distance or near F1NPP, which can be ascribed to the slowly natural corrosion of CsMPs by the loss of the small amount of soluble contents in CsMPs, and (3) high CsMPs concentration of 10 granules/g in the surface soil of our sampling site and high resuspension frequency of CsMPs in spring when predominant suspended particles were soil dust. Specifically, 15 single CsMPs were successfully isolated from the aerosol filters collected by unmanned high-volume air samplers at a severely polluted area in Fukushima Prefecture, about 25 km away from F1NPP, from January 2015 to September 2019. The mean diameter of these CsMPs was 1.8 ± 0.5 μm, and the average 137Cs radioactivity was 0.35 ± 0.23 Bq/granule. The contribution rate of the resuspended CsMPs to the atmospheric radiocesium was estimated from the ratio of 137Cs radioactivity of a single CsMP to that of the aerosol filter to be of 23.9 ± 15.3%. There has been no considerable decreasing trend in the annual CsMP resuspension frequency.

Radiocesium dynamics data during food processing are required for the realistic estimation of internal radiation content in food. Radiocesium contamination of leafy vegetables can occur externally due to the adhesion of fallout and/or resuspension from the air, and internally from soil via the root transport. Information regarding the dynamics of both surface and internal radiocesium contamination during food processing is required; however, such information for leafy vegetables is limited compared to other major agricultural products. In this study, the effect of washing on the removal of surface radiocesium contamination by resuspended materials and that of cooking (grilling, boiling, and microwave heating) on internal radiocesium contamination were investigated using komatsuna (Brassica rapa var. perviridis), a leafy vegetable. The surface-contaminated samples were experimentally grown in a difficult-to-return area in Fukushima Prefecture, which has not yet been decontaminated. The internally contaminated komatsuna were obtained after experimental cultivation in a greenhouse with soil containing 137Cs and no surface contamination. The concentration of 137Cs in surface-contaminated komatsuna was reduced to approximately half (processing factor: 0.55) after washing with water. However, the annual processing factor ranged from 0.12 to 0.95, suggesting that the growing environment and climatic conditions may affect the removal rate of radiocesium by washing. Internal contamination of 137Cs was removed by 23% and 14% by boiling and grilling, respectively, but no effect was observed for microwaving. Moreover, the concentration of 137Cs decreased by 0.66-fold after boiling, while it increased by 1.19- and 1.20-fold after grilling and microwaving, respectively. Therefore, boiling was found to be preferable than grilling or microwaving for radiocesium removal.

As the next step that occurred more than one decade after the accident at the Fukushima Dai‐ichi Nuclear Power Station (FDNPS), decontamination and demolition have been carried out in the Specified Reconstruction and Revitalization Base (SRRB) of the difficult‐to‐return zone around the FDNPS. However, the risk of internal exposure among workers due to airborne dust inhalation after building demolition operations has not been sufficiently evaluated. To evaluate the working environment and internal exposure risk due to inhalation in the SRRB of Tomioka town, Fukushima Prefecture, the cesium‐137 (137Cs) radioactivity levels in the airborne dust at building demolition sites were analyzed using gamma spectrometry. The 137Cs radioactivity levels and resuspension factors of the airborne dust at the subject building sites in the difficult‐to‐return zone remained at high levels compared with those of the control, which was located in the evacuation order‐lifted area in Tomioka town. However, the 137Cs radioactivity levels did not increase significantly, despite demolition operations that used heavy machinery. In this case, no substantial increases in accident‐derived 137Cs levels due to decontamination and demolition in the SRRB of Tomioka town, Fukushima Prefecture, were observed in the airborne dust samples, which suggests that the 137Cs radioactivity in the airborne dust is primarily associated with particles that are resuspended by localized winds accompanied by the transfer of construction vehicles as opposed to the decontamination and demolition operations. However, the internal exposure doses due to aspirating airborne dust containing 137Cs were extremely low compared with the estimated annual effective doses of decontamination workers or the limits recommended by the Japanese government. Additionally, countermeasures such as wearing protective masks could help reduce the on‐site inhalation of soil‐derived radionuclides. Integr Environ Assess Manag 2022;18:1555–1563. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Key points: No substantial increase in accident‐derived 137Cs due to demolition in areas close to the Fukushima Dai‐ichi Nuclear Power Station was observed in the airborne dust.137Cs radioactivity in the airborne dust is primarily associated with particles resuspended by localized wind accompanied by transfer of construction vehicles. [ABSTRACT FROM AUTHOR]

The effect of the mineral content of polyfloral honey produced by bees in the conditions of the northern Polissia of Ukraine (the zone affected by the Chernobyl nuclear power plant accident) on the level of accumulation of 137Cs, Pb and Cd in it was studied. It was established that the specific activity of 137Cs and the concentration of Pb and Cd in polyfloral honey depended on the content of mineral substances (ash) in this product. In the polyfloral honey produced by bees from the nectar of autumn pollinators (heather, various grasses), a higher specific activity of 137Cs and the concentration of Pb and Cd were found in comparison with the same products obtained from spring nectar pollinators (apple, cherry, cherry, white acacia, spring rhinoceros ). At the same time, it was found that the content of mineral substances in polyfloral honey produced by bees from autumn honey combs was 64.7% higher compared to this product produced from spring nectar pollen cones. The artificial reduction of ash content in polyfloral honey by 2.4 times due to its processing using sorption technologies contributed to the improvement of the quality of this product. In particular, a decrease in the specific activity of 137Cs by 47.5% and the concentration of Pb by 59.5% and Cd by 41.2% was observed in the processed honey. At the same time, a decrease in sucrose by 1.18 pp, ash by 2.4 times and an increase in the content of amino acids by 58.8% was observed in honey. [ABSTRACT FROM AUTHOR]

Despite the propensity of waterfowl species to readily accumulate anthropogenic contaminants within polluted environments, few studies have examined bioaccumulation rates over time when entering such a contaminated site. We examined mercury (Hg) and radiocesium (137Cs) bioaccumulation over time in two waterfowl species released into a wetland system containing legacy contamination on the US Department of Energy's Savannah River Site in South Carolina. Released birds were collected at select time intervals over an exposure period of 94 days. We quantified total Hg concentrations in blood, muscle, and liver tissues, and 137Cs activity in whole‐body and muscle tissues. The relationship between the contaminant burdens of different body tissue types was examined over time. Likely a result of microhabitat selection, mallards in our study readily accumulated both Hg and 137Cs at consistent rates over time within our study system, while ring‐neck ducks did not. The findings demonstrated that whole blood can be used as a robust, nondestructive sampling alternative to estimate Hg burdens within muscle and liver, and whole‐body 137Cs activity is a good predictor of muscle burdens. Understanding such bioaccumulation information in waterfowl is useful for the assessment of the potential health risk in wildlife, as well as being important for human risk assessment toward the consumption of popular game species. Environ Toxicol Chem 2022;41:2479–2487. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]

Countermeasures to reduce radiocesium uptake by crops have been implemented in farmlands affected by the accident at Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Plant in 2011. A widely practiced countermeasure is the application of K. Long-term maintenance of soil K is crucial due to the long physical half-life of 137Cs (30 years). Plant-available K budgets can be used as an indication of sustainable maintenance. Our previous study found that large water outflow, especially percolation, associated with excessive irrigation caused major K outflow and a negative K budget in a paddy field in Fukushima in 2018. The present study evaluated whether decreasing the water outflow by reducing the irrigation volume from 6300 to 1900 mm reduced K outflow and improved the K budget in the field during the cropping period in 2019. K concentrations in soil solution were comparable in both years, and the percolation water volume decreased to 37% that of 2018, resulting in a 53% reduction in the K output from 392 to 184 kg ha–1. The input via irrigation also decreased (−35 kg ha–1), but the output via surface runoff showed a greater reduction (−58 kg ha–1) owing to a 70% decrease in the water volume compared with 2018. Consequently, the K budget was substantially improved (from −289 to −57 kg ha–1), highlighting the importance of controlling water outflow, particularly percolation, for soil K maintenance in paddy fields with high permeability. [ABSTRACT FROM AUTHOR]

In the wake of Chernobyl and Fukushima accidents, radiocesium has become a radionuclide of most environmental concern. The ease with which this radionuclide moves through the environment and is taken up by plants and animals is governed by its chemical forms and site-specific environmental characteristics. Distinctions in climate and geomorphology, as well as 137Cs speciation in the fallout, result in differences in the migration rates of 137Cs in the environment and rates of its natural attenuation. In Fukushima areas, 137Cs was strongly bound to soil and sediment particles, with its bioavailability being reduced as a result. Up to 80% of the deposited 137Cs on the soil was reported to be incorporated in hot glassy particles (CsMPs) insoluble in water. Disintegration of these particles in the environment is much slower than that of Chernobyl-derived fuel particles. The higher annual precipitation and steep slopes in Fukushima-contaminated areas are conducive to higher erosion and higher total radiocesium wash-off. Among the common features in the 137Cs behavior in Chernobyl and Fukushima are a slow decrease in the 137Cs activity concentration in small, closed, and semi-closed lakes and its particular seasonal variations: increase in the summer and decrease in the winter. [ABSTRACT FROM AUTHOR]

Highlights: What are the main findings? The first radiocesium and Pu isotopes data in Korean seas were present in 2011–2012; Higher 134Cs were observed in Korean seas immediately after the Fukushima accident; Fukushima-derived nuclides were introduced to Korean seas by the atmosphere for up to 2 months. What is the implication of the main finding? The residence times of 137Cs in Korean seas water is estimated to be 8–25 years; The dataset could be used to predict the dispersion of anthropogenic pollutant; The dataset could also be used to validate the model for future NPP accident around the Korean seas. The distributions of artificial radionuclides, radiocesium (134Cs and 137Cs) and plutonium isotopes (238Pu and 239+240Pu), in the surface water around the Korean seas (East/Japan Sea and Yellow Sea) in 2011–2012 and in three sections in the North Pacific between 2011 and 2014 were examined. The 137Cs activities in the surface water in the Korean seas in 2011 (immediately after the Fukushima nuclear power plant (NPP) accident on 17 March 2011) were comparable or not significantly different relative to those in 2010 and 2012. However, 134Cs, which had been not detected in the study area before the Fukushima accident (under the detection limit of 0.1 mBq kg−1 level), were detected rapidly in 2011 after the accident (in about 60% of the 72 samples) and gradually disappeared due to their short half-life (t1/2 = 2.06 years) in 2012 (detected in about 16% of the 24 samples). In addition, the highest activities of radiocesium and Pu isotopes appeared locally in some stations of the Korean Strait region (located between Korea and Japan) within 1–2 months immediately after the accident. This suggests that the radioactive nuclides released immediately after the Fukushima accident were significantly introduced through the atmosphere, based on recent studies conducted in neighboring areas. We also showed that the spatial distribution of radiocesium in the North Pacific moved eastward from 2012 to 2014, and we attempted to quantify the residence time of radiocesium (137Cs) in the Korean seas based on the long-term (tens of years scale) temporal trends of 137Cs activity data, which have been collected since the 1960s and 1970s. The estimated retention time of 137Cs in the East/Japan Sea and Yellow Sea were 25 ± 0.6 and 8.0 ± 0.1 years, respectively. These results are expected to be used as a preliminary study for a potential future event of a marine radioactive accident (which, of course, cannot be predicted) and as basic data for predicting the influences of radionuclide releases in the ocean. [ABSTRACT FROM AUTHOR]

To investigate the changes in the characteristics of the main inorganic elements in wild game meat during cooking, and to compare the relationship between radiocesium and each inorganic element, the inorganic elements in cooked meat samples were determined after radiocesium analysis. Values for the mean food processing retention factor (Fr), i.e., the ratio of the amount of an element in cooked meat to the amount in raw meat, of K, Na, Mg, and P were 0.8, 0.9, 0.9, and 0.9 for grilling; 0.6, 0.6, 0.7, and 0.7 for boiling; and 0.5, 0.5, 0.7, and 0.7 for steaming, respectively. All of the elements were reduced after cooking. The Fr value was lower for boiling and steaming with water than for grilling. Values for the mean processing factor (Pf), i.e., the ratio of the concentration of an element in cooked meat to the concentration in raw meat, of K, Na, Mg, and P were 1.2, 1.2, 1.2, and 1.2 for grilling; 0.8, 0.8, 1.0, and 1.0 for boiling; and 0.8, 0.8, 1.1, and 1.1 for steaming, respectively. The concentrations of these elements were increased after grilling, and the Pf values were greater than 1.0. K, which was similar to the behavior of radiocesium in cooked meat, including Fr and Pf. The findings showed that K could serve as a proxy for assessing the characteristics of radiocesium in cooked meat. [ABSTRACT FROM AUTHOR]

The radiocesium ( 134 Cs and 137 Cs) released by the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011 has a relatively long physical half-life and may remain in the natural environment for a long period of time and continue to be transferred to wildlife. In this study, we conducted a fixed-point investigation of radiocesium activity concentrations in stomach contents and skeletal muscles samples of wild rodents (Apodemus speciosus, Apodemus argenteus and Microtus montebelli) and insectivores (Urotrichus talpoides) from 2012 to 2021. Two sampling sites in Mt. Kuchibutoyama and Mt. Hayama were selected in forested areas in Fukushima Prefecture. In Mt. Kuchibutoyama, a decreasing trend in 137 Cs activity concentrations was observed for stomach contents of wild rodents and insectivores as a whole and for skeletal muscle of A. speciosus and A. argenteus. The effective half-life (T ef ) of 137 Cs activity concentration was estimated to be 7.6 years in the stomach contents, and 5.4 years and 7.4 years in skeletal muscle of A. speciosus and A. argenteus, respectively, with corresponding ecological half-life (T ec ) of 10 years in the stomach contents, and 6.6 years (A. speciosus) and 9.8 years (A. argenteus) in the skeletal muscle. In Mt. Hayama, there was a slight upward trend in the 137 Cs activity concentration in the stomach contents of wild rodents and insectivores, and no significant T ef could be obtained. Statistically significant T ef and T ec could not also be estimated for 137 Cs radioactivity levels in skeletal muscle of A. speciosus and A. argenteus. These results suggest that 137 Cs concentration in insects and plants eaten by wild rodents and insectivores in Mt. Hayama has remained at a certain level for a long time. In November 2021, 137 Cs concentrations above 1.0 kBq/kg were still detected in skeletal muscle of A. argenteus captured in Mt. Kuchibutoyama and A. speciosus and A. argenteus captured in Mt. Hayama. It is expected that 137 Cs concentration levels in the stomach contents and skeletal muscles of these wild rodents and insectivore will remain for a long time to come, especially at Mt. Hayama. Furthermore, we also collected soil and plant samples when sampling wild rodents and insectivores in this study. It is important as a future task to study temporal changes in radiocesium activity concentrations in the habitat of wild small mammals and to examine the relationship between these changes and temporal changes in radiocesium activity concentrations in wild small mammals., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Removing the hazardous and unstable radioactive isotopes has been considered an arduous task, though they are in minimal concentrations. Cesium-137 (137Cs+) is a primary fission product produced by nuclear processes. Even at low concentrations, such radioactive material is a menacing source of contaminants for the environment. The current study aims to separate 137Cs+ from a real contaminated aqueous solution via an ion exchange mechanism using ammonium molybdophosphate–polyacrylonitrile (AMP-PAN) resin loaded in an extraction chromatographic column that possesses considerable selectivity toward cesium ion (Cs+) due to the specific ion exchange between 137Cs+ and NH4+. Additionally, the proposed interaction mechanism between 137Cs+ with APM-PAN resin has been illustrated in this study. The results disclosed that the optimum efficient removal of 137Cs+ (91.188%) was obtained by the AMP-PAN resin using 2 g·L−1, while the distribution adsorption coefficient (129.359 mL·g−1) was at pH 6. The isothermal adsorption process was testified through the Langmuir and Freundlich models. The estimated maximum adsorption capacity reached 140.81 ± 21.3 mg·g−1 for the Freundlich isotherm adsorption model. Finally, AMP-PAN resin could eliminate 137Cs+ from water effectively through adsorption.

Wild boar meat containing radioactive cesium (Cs) of approximately 1,000 Bq/kg (134Cs+137Cs) was processed into bacon, sausage, and ham. To understand the concentration and quantity change of radioactive Cs, the processing factor (Pf) and food processing retention factor (Fr) were calculated. The radioactive Cs quantity in the meat did not reduce during smoking. The dehydration-related meat mass reduction during smoking without decrease of radioactive Cs led to Cs condensation in the bacon compared with the raw rib meat before processing, resulting in a Pf of 1.18. Soaking in liquid, such as pickling in liquid and desalting or boiling in water, effectively removed radioactive Cs by leakage into water. Therefore, the Fr value of the boiled ham produced from a loin meat block through three liquid-soaking processes was 0.27. The Pf value of the boiled ham was 0.30 due to meat block mass reduction after boiling as a result of dehydration, along with protein thermal denaturation-related muscle tissue shrinkage. The steamed ham Fr value was 0.53, because the removal of radioactive Cs was less efficient by steaming than by boiling. The Pf value of the steamed ham was 0.54, almost the same as the Fr value, because the mass decrease rate was the same as the radioactive Cs decrease rate by steaming. The Fr and the Pf values of the boiled sausage, whose processing did not include soaking in the pickling liquid, were 0.64 and 0.62, respectively. Steaming the sausage meat did not remove radioactive Cs during the dehydration-related mass reduction, leading to Fr and Pf values of 1.01 and 1.17, respectively. This study found that processing into boiled ham was the most effective measure for reducing radioactive Cs quantity and concentration in raw meat. Processing into bacon and steamed sausage showed no Cs quantity reduction, with the moisture loss resulting in Cs condensation compared with the raw material. sausage, and ham were made from boar meat contaminated with radioactive Cs. into bacon and steamed sausage increased the Cs concentration in meat. in pickling liquid or water and boiling in water effectively removed Cs. into boiled ham reduced the amount of Cs to 27% in raw meat. was less effective than boiling for Cs reduction in meat. [ABSTRACT FROM AUTHOR]

An in situ model paddy field experiment was conducted using non-contaminated soil to identify factors that locally increase the radiocesium activity concentrations in rice near the water inlet of paddy fields. The results demonstrated that irrigation water intake reduced exchangeable potassium concentration and increased radiocesium activity concentration in the soil near the water inlet; thus, the radiocesium activity concentration in rice was negatively correlated with the former and positively with the latter. Exchangeable potassium flushing and deposition of suspended solids in the soil owing to irrigation water intake facilitated the transfer of radiocesium to rice plants near the water inlet. [ABSTRACT FROM AUTHOR]