Radiocesium accumulation in the anuran frog, Rana tagoi tagoi, in forest ecosystems after the Fukushima Nuclear Power Plant accident

This work is the first evaluation of environmental gamma exposure rates by the Nuclear Medicine Department at Lin Shin Hospital (LSH) in Taichung with Thermoluminescent dosimeter (TLD-100H) during the Fukushima Nuclear Power Plant (FNPP) accident. After the 9.0 MW strong earthquake hit northern Japan on March 11, 2011, a TLD-100H was used to monitor environmental kerma rate at Taichung (2,500 km away from northern Japan) from Mar-08 to Apr-09, 2011 and evaluated kerma rate due to global fallout of the sever FNPP accidents. Exposure rates varied widely among positions close to the PET/CT facility. Observed kerma rates of up to 4.12 ± 0.62 mSv mo−1 indicated an explicit, heavy leakage of photon through the PET/CT facility. No significant contributions were detected at Taichung, Taiwan. Hence, the health effect cause by the “extra radiation” from FNPP accidents is negligible. As this was a rare case of environmental monitoring during a nuclear power plant accident, its findings are of considerable significance.

Atmospheric input of 137Cs and 239,240Pu isotopes in Korea after the Fukushima nuclear power plant accident

Abstract. Huge amounts of radionuclides, especially 137Cs, were released into the western North Pacific Ocean after the Fukushima nuclear power plant (FNPP) accident that occurred on 11 March 2011, resulting in contamination of the marine biota. In this study we developed a radioecological model to estimate 137Cs concentrations in phytoplankton and zooplankton populations representing the lower levels of the pelagic trophic chain. We coupled this model to a lower trophic level ecosystem model and an ocean circulation model to take into account the site-specific environmental conditions in the area. The different radioecological parameters of the model were estimated by calibration, and a sensitivity analysis to parameter uncertainties was carried out, showing a high sensitivity of the model results, especially to the 137Cs concentration in seawater, to the rates of accumulation from water and to the radionuclide assimilation efficiency for zooplankton. The results of the 137Cs concentrations in planktonic populations simulated in this study were then validated through comparison with the data available in the region after the accident. The model results have shown that the maximum concentrations in plankton after the accident were about 2 to 4 orders of magnitude higher than those observed before the accident, depending on the distance from FNPP. Finally, the maximum 137Cs absorbed dose rate for phyto- and zooplankton populations was estimated to be about 5 × 10−2 µGy h−1, and was, therefore, lower than the predicted no-effect dose rate (PNEDR) value of 10 µGy h−1 defined in the ERICA assessment approach.

We summarized temporal changes in air dose rates and radionuclide deposition densities over five years in the 80 km zone based on large-scale environmental monitoring data obtained continuously after the Fukushima Nuclear Power Plant (NPP) accident, including those already reported in the present and previous special issues. After the accident, multiple radionuclides deposited on the ground were detected over a wide area; radiocesium was found to be predominantly important from the viewpoint of long-term exposure. The relatively short physical half-life of 134Cs (2.06 y) has led to considerable reductions in air dose rates. The reduction in air dose rates owing to the radioactive decay of radiocesium was more than 60% over five years. Furthermore, the air dose rates in environments associated with human lives decreased at a considerably faster rate than expected for radioactive decay. The average air dose rate originating from the radiocesium deposited in the 80 km zone was lower than that predicted from radioactive decay by a factor of 2–3 at five years after the accident. Vertical penetration of radiocesium into the ground contributed greatly to the reduction in air dose rate because of an increase in the shielding of gamma rays; the estimated average reduction in air dose rate was approximately 25% with penetration compared to that without penetration. The average air dose rate measured in undisturbed fields in the 80 km zone was estimated to be reduced owing to decontamination by approximately 20% compared to that without decontamination. The average deposition density of radiocesium in undisturbed fields has decreased owing to radioactive decay, indicating that the migration of radiocesium in the horizontal direction has generally been slow. Nevertheless, in human living environments, horizontal radiocesium movement is considered to contribute significantly to the reduction in air dose rate. The contribution of horizontal radiocesium movement to the decrease in air dose rate was estimated to vary by up to 30% on average. Massive amounts of environmental data were used in extended analyses, such as the development of a predictive model or integrated air dose rate maps according to different measurement results, which facilitated clearer characterization of the contamination conditions. Ecological half-lives were evaluated in several studies by using a bi-exponential model. Short-term ecological half-lives were shorter than one year in most cases, while long-term ecological half-lives were different across the studies. Even though the general tendency of decrease in air dose rates and deposition densities in the 80 km zone were elucidated as summarized above, their trend was found to vary significantly according to location. Therefore, site-specific analysis is an important task in the future.

We measured (134)Cs and (137)Cs in the surface soil of the Kanto loam in the eastern Tokyo metropolitan area and the Nishiyama loam in Nagasaki, Japan. The observed (137)Cs deposition in the Kanto loam from the Fukushima nuclear power plant (NPP) accident ranged from 4.0 to 77 kBq m(-2), which corresponds to 0.3-5 times of that in the Nishiyama loam. The (137)Cs retardation factor in the Kanto loam obtained seven months after the Fukusima NPP accident and in the Nishiyama loam after 36 and 38 years from the detonation of the Pu atomic bomb (A-bomb) ranged from 180 to 260 and 2000 to 10,000, respectively. This difference in the retardation factors is attributed to an aging effect that corresponds to seven months and 36 to 38 years after the deposition of (137)Cs occurred on the soil minerals.

During January–March 2011, 29 atmospheric Δ14CO2 samples were measured along the R/V Xuelong cruise track from Zhongshan Station (69.37°S, 76.38°E; Antarctica) to Shanghai. The extent of fossil fuel contamination in the samples was evaluated by comparison with contemporary hemispheric-scale averages of Δ14CO2, together with transport analysis and consideration of the δ13CO2 levels in the samples. Generally, the Δ14CO2 levels along the route south to 40.67°S were lower than the hemispheric-scale average. Circumpolar deep water (CDW) upwelling, stratosphere–troposphere transport (STT), and regional transport associated with the Fukushima nuclear power plant (NPP) accident in Japan on 12 March 2011 were found to have influenced Δ14CO2 levels at the sampling sites. In comparison with the atmospheric Δ14CO2 level (45.7 ± 3.5‰ (1σ)) measured in the coastal region of East Antarctica, CDW upwelling caused reduction of ∼10‰ in Δ14CO2 in two cross sections: 62.0°–64.0°S along 74.0°E and 51.7°–54.0°S along 80.5°–84.0°E. Conversely, STT-enhanced Δ14CO2 was ∼7‰ (∼3‰) at Zhongshan (around 45.0°S). The linkage was supported by a certain Model-3/CMAQ simulation that indicated dispersion of radionuclides from the Fukushima NPP accident over the East Asian region, which explained the individual high Δ14CO2 (52‰) level on 29 March 2011 in Shanghai.

By earthquake and tsunami occurred on March 11 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</sup> 2011, Fukushima nuclear power plant No.1 has generated severe accidents to emit high level radiations and to contaminate foods, water and others with radio isotopes. Such an accidents has given very important messages such as unclearness for safety and cost effectiveness of nuclear energy and important of clean renewable energies including photovoltaics instead of nuclear energy to us. This report presents outline of accidents by the Fukushima nuclear power plant and difficulty of further installation of new nuclear power plants in Japan. An idea such as the "Fukushima Solar Village" plan has been proposed to attain employment security, to maintain power supply from those areas to metropolitan cities and to overcome several problems occurred by nuclear power plant accident. Accelerating plan such as further installation of photovoltaic power generation systems in Japan has also been proposed in order to overcome several problems occurred by Fukushima nuclear power plant accident.

Long-lasting effects of distrust in government and science on mental health eight years after the Fukushima nuclear power plant disaster.

The Fukushima nuclear power plant (FNPP) accident raised worldwide attention to the health risk of radiation exposure and to its potential transgenerational effects. Here, we analysed transgenerational effects on calf spermatogenesis and on blood plasma metabolome in order to detect alterations associated with paternal exposure to low-dose-rate (LDR) radiation. Sperm was collected from a bull exposed to radiation for 2 years abandoned in the ex-evacuation zone of the FNPP accident (the abandoned bull) and was used for artificial insemination (AI) into a non-radiocontaminated cow. Haematoxylin and eosin stained sections of the testis of a 13-month-old calf revealed spermatogonia, spermatocytes, spermatids, and sperm in normal morphology. Nuclear and acrosomal morphology of sperm was generally normal. Metabolomic profiling of plasma using capillary electrophoresis–mass spectrometry resulted in 104 peaks of candidate compounds suggestive of paternal exposure. A calf was delivered by AI using sperm from the abandoned bull. Regarding glycolysis, the contents of nucleotide sugars tended to be lower in the delivered calf than in the control calf. Among energy carries, AMP and ATP showed different tendency between non-radiocontaminated and delivered calf. In conclusion, there were no apparent transgenerational effects on both spermatogenesis and blood plasma metabolome in a calf obtained by AI using sperm from the abandoned bull exposed to LDR in the ex-evacuation zone of the FNPP accident for about 2 years.

Accumulations of radionuclides in marine macroalgae (seaweeds) resulting from the Fukushima 1 Nuclear Power Plant (F1NPP) accident in March 2011 have been monitored for two years using high-purity germanium detectors. Algal specimens were collected seasonally by snorkeling at Nagasaki, Iwaki, Fukushima Prefecture (Pref.), Japan, ca. 50 km perimeter from the F1NPP. Additional collections were done at Soma, Hironocho, Hisanohama and Shioyazaki in Fukushima Pref. as well as at Chiba Pref. and Hyogo Pref. as controls. In May 2011, specimens of most macroalgal species showed 137Cs levels greater than 3,000 Bq kg−1 at Shioyazaki and Nagasaki. The highest 137Cs level recorded 7371.20 ± 173.95 Bq kg−1 in Undariapinnatifida (Harvey) Suringar on 2 May 2011, whereas seawater collected at the same time at Shioyazaki and Nagasaki measured 8.41 ± 3.21 and 9.74 ± 3.43 Bq L−1, respectively. The concentration factor of marine macroalgae was estimated to be ca. 8–50, depending on taxa and considering a weight ratio of wet/dry samples of ca. 10. 137Cs level declined remarkably during the following 5–6 months. In contrast, the 137Cs level remained rather stable during the following 12–16 months, and maintained the range of 10–110 Bq kg−1. Contamination was still detectable in many samples in March 2013, 24 months after the most significant pollution.

Worry about radiation persists long after nuclear power plant accidents. Young age, low socioeconomic status, being married, and disaster-related experiences are known to be associated with greater worry about radiation. This study explored the duration of the effects of these risk factors on worry about radiation after the 2011 Fukushima nuclear power plant accident, using the longitudinal data of randomly sampled non-evacuee community residents who were followed five to ten years after the accident. Questionnaire surveys were conducted five times with 1825 respondents (37.2% of the 4900 initial targets). We examined the interaction of time and risk factors of worry about radiation using a mixed model. Fear or anxiety immediately after the accident had effects on worry about radiation that continued even after 10 years, though it slightly attenuated with time. Family problems stemming from the disaster retained their effects. While direct damage and evacuation experience were significantly associated with worry about radiation in the early phase, their effects diminished and became non-significant during the study period. Being under the age of 65, having low educational attainment, and being married were significantly associated with worry about radiation, although the association with age weakened over time. Individuals who experience intense fear or anxiety post-nuclear power plant accidents or disaster-related family problems may need continuous monitoring for their worry about radiation even 10 years after such accidents.

Social networks and posttraumatic stress symptoms five to ten years after the Fukushima nuclear power plant disaster

Immediately after the Great East Japan Earthquake on March 11, 2011, the public could not receive accurate information concerning about the reality of the accident at the Fukushima Nuclear Power Plant because of communication problems with mobile phone base stations caused by power outages and the inadequate use of communication satellites between local governments. These telecommunications troubles caused not only a delay between the Japanese central government to local governments, but also a failure in conveying the seriousness of the accident to residents. The central government issued evacuation orders, but in some areas, a delay was seen in the time residents took to notice the orders. Some residents were forced to change their evacuation site several times and move to areas with higher radiation exposure. Although iodine preparations needed to be distributed to saturate the thyroid gland and reduce the uptake of iodine-131, a radioactive isotope, many municipalities were unable to secure them. Preparations were distributed on March 15, 2011 when the detectable amount of radioactive isotopes peaked, but only the Naraha and Miharu towns received them. At the time of the Fukushima Nuclear Power Plant accident, communication lines had already been interrupted by the major earthquake that struck on March 11, and information systems between local governments were not communicating well. With such a social infrastructure, residential evacuation orders were inadequate, and the delivery of medication was extremely difficult. The experience of the Fukushima Nuclear Power Plant accident suggests that the government should have distributed iodine preparations to residents living within a 30-km radius of the plant in advance, so that they could learn about the background and side effects of the drug beforehand. This distribution strategy is similar to that of targeted antivirus prophylaxis (TAP), which is an extralegal policy carried out in situations where face-to-face medical treatment is impossible because of an outbreak during a pandemic.

Background. The study of the long-term effects of chronic radiation exposure on plants and animals, which are still the subject of scientific discussion, is necessary to understand the consequences of radiation accidents. After the Fukushima nuclear power plant accident, some of the young pines and spruces showed an increased frequency of apical dominance cancelling. The most probable cause of the observed morphoses is associated with damage to the apical meristem of coniferous plants by radiation in the first year of the accident, when they received the highest absorbed doses. If this hypothesis is true, then even 8 years after the accident it will be possible with high degree of probability to detect an increased level of cytogenetic abnormalities in the intercalary meristem of needles of plants from these populations. The aim of this work was to verify this hypothesis. Materials and methods. Five populations of Japanese red pine from territories contaminated with radionuclides as a result of the accident at the Fukushima nuclear power plant were investigated. The frequency and spectrum of cytogenetic abnormalities in the intercalary meristem of needles were determined by the ana-telophase analysis. Results. The frequency of aberrant cells in the needles intercalary meristem of Japanese red pine from the contaminated with radionuclides territory statistically significantly exceeds the control level in all impact sites and increases along with the dose rate. Although there is no correlation between the frequency of cytogenetic abnormalities in needles and the presence of cancellation of apical dominance in plants, all pine populations from radioactively contaminated territories are characterized by an increased frequency of both cytogenetic abnormalities and morphoses associated with the cancellation of apical dominance. Conclusion. Radiation damage to the apical meristems of conifers in the first year of the accident, when they received the highest absorbed doses, is the most likely cause of the increased frequency of cancellation of apical dominance in the studied populations of Japanese red pine from the zone affected by the accident at the Fukushima nuclear power plant.

Radiocesium (Cs) contamination histories of the Japanese flounder, Paralichthys olivaceus, after the 2011 Fukushima Nuclear Power Plant (FNPP) accident were examined by analysis of the spatiotemporal changes in observed Cs concentrations, by comparison of the dynamics of the Cs concentrations in several year-classes of fish, and by simulation studies. Two contamination histories were revealed: (1) severe contamination by water that was directly released from the FNPP with extremely high Cs concentrations for a few months after the accident, which had a highly variable spatial distribution; and (2) long-duration contamination at relatively low concentrations resulting from consumption of contaminated food. These two histories were supported by three observations. First, high Cs concentrations with high variability were observed in the first year after the accident. Second, the highest values of the minimum Cs concentrations were observed in the autumn of 2011. Third, Cs concentrations were lower with smaller variation for fish from the 2011 year-class and younger, which were not exposed to the highly contaminated directly released water, than for fish from the 2010 year-class and older. Simulation studies also indicated that the Cs concentrations in some individuals that were exposed to the directly released water might not be in an equilibrium state even at 3 years after the accident. On the basis of these contamination histories, it can be expected that the Cs concentrations in most Japanese flounder will continue to decrease.