The Overview of Our Research

Nakanishi, Teruyuki

doi:10.1007/978-4-431-54328-2_1

Cited by 8 publications

(3 citation statements)

References 11 publications

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“…[ 22 ]. However, the integrity of local agricultural products was damaged due to radiation contamination, and consequently these agricultural products, though deemed safe, are no longer marketable [ 18 , 78 ]. Due to the slow sale of crops, many peasant families no longer expect to experience an agricultural renaissance.…”

Section: Reasons For Emigrationmentioning

confidence: 99%

Radiation-Driven Migration: The Case of Minamisoma City, Fukushima, Japan, after the Fukushima Nuclear Accident

Zhang

Yan

Oba

et al. 2014

IJERPH

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The emigration of residents following the Fukushima nuclear accident has resulted in aging and depopulation problems in radiation-contaminated areas. The recovery of affected areas, and even those areas with low radioactive pollution levels, is still heavily affected by this problem. This slow recovery consequently affects immigration patterns. This review aims to present possible factors that have contributed to this dilemma. We first present an overview of the evacuation protocol that was administered in the study area following the Fukushima accident. We then analyze characteristics of the subsequent exodus by comparing population data for both before and after the accident. Based on the findings of existing literature, we identify three causes of emigration: (1) The health risks of living in a low radiation zone are still unknown; (2) The post-disaster psychological disturbance and distrust of government information promotes the emigration of evacuees; (3) an absence of economic vitality and of a leading industry renders the area less attractive to individuals residing outside of the city. Further research is needed on this issue, especially with respect to countermeasures for addressing this problem.

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Section: Reasons For Emigrationmentioning

confidence: 99%

Radiation-Driven Migration: The Case of Minamisoma City, Fukushima, Japan, after the Fukushima Nuclear Accident

Zhang

Yan

Oba

et al. 2014

IJERPH

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“…Adsorption of FRNs on plant surfaces, including crops, has been found to be potentially significant (e.g. Reissig, 1965;Nakanishi, 2013), 370 and thus a certain proportion of the introduced plutonium could have been lost during crop harvest during the early 1960s.…”

Section: Temporal Limitation Of 239+240 Pu Topsoil Concentrationsmentioning

confidence: 99%

Plutonium concentrations link soil organic matter decline to wind erosion in ploughed soils of South Africa

Mohren,

Wiesel,

Amelung

et al. 2024

Preprint

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Abstract. Losses of soil organic matter (SOM) from arable land poses a serious threat to soil fertility and crop yields, and thwarts efforts to conserve soils as carbon sinks to mitigate global warming. Wind erosion can be a major factor in the redistribution of soil fines including SOM, but assessments of its impact have typically been limited by short observation periods of a few years at most. Longer timeframes, extending back to the mid 20th century, may however be probed using the concentrations of radionuclides that were globally distributed by nuclear weapon tests conducted 1950s and early 1960s. The basic concept is that differences in fallout radionuclide (FRN) activities between undisturbed and arable soils can be used to infer soil particle redistribution. In the present work, we have measured activities of 137Cs and 239+240Pu in soils from three agricultural regions of the plains of the South African Highveld. The three regions represent distinct agroecosystems and within each region the temporal length of cultivation varies from zero (i.e., native grassland) to almost 100 years. The sampled plots did not show any evidence of fluvial erosion, allowing the contribution of wind erosion to the loss of soil fines, including SOM, to be investigated. For the cultivated soils, radionuclide activities are found to be less than in adjacent native grassland, and the magnitude of the reduction is strongly correlated with the duration of cultivation. Specifically, the original concentrations of both 137Cs and 239+240Pu are approximately halved after ~25–45 years of cropping. The initial rate loss relative to the undisturbed soils is, however, considerably higher, with ~6 % yr-1 recorded during the first year after native grassland is converted to arable land. We correlate our radionuclide data with previously published SOM contents from the same sampled material and find that the radionuclides are an excellent indicator of SOM decline at the sites we investigate. We conclude that wind erosion can exert a dominant control on SOM loss in arable land of South Africa and by implication at comparable settings on Earth.

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“…In autoradiography, charged α and β radiation particles emitted from radioactive elements in samples are recorded by the IP, from which two-dimensional information about the radioactivity distribution in the sample is obtained. After the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in 2011, IPs were used to analyze contaminated plants sampled from the environment [8][9][10], and advanced X-ray microradiography techniques for plant cells were also developed [11]. If the radioactivity level in a sample is low, the required IP exposure time can be one month or even longer.…”

Section: Introductionmentioning

confidence: 99%

Low-Background Shielding Box for Autoradiography of Environmental Samples and the α-, β-, and γ-ray Sensitivities of the Imaging Plates

Shizuma

Oba

2019

Applied Sciences

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Autoradiography using imaging plates is a conventional method for the visualization of the distribution of radionuclides. Imaging plates have high sensitivity to the charged particles of α- and β-rays but are also sensitive to γ-rays. When the radioactivity level in the sample is low, a longer exposure time is needed, and shielding of the natural background radiation is necessary. Large imaging plates (e.g., 35 × 40 cm), which can obtain the radioactivity distribution over a wider area, were developed. In this work, a low-background shielding box is developed for large imaging plates, and the shielding characteristics of the box and sensitivities of the imaging plate to α-, β-, and γ-rays are quantitatively investigated. It is shown, by considering the sensitivity of imaging plates to α-, β-, and γ-rays, that most images of environmental samples are the result of α- or β-rays emitted from radionuclides at the sample surface, but not from the whole sample. To exemplify autoradiography using the presented shielding box, some environmental samples contaminated with radioactive fallout from the Fukushima Daiichi Nuclear Power Plant accident are measured. The distribution of radionuclides is clearly visualized and, furthermore, information of the migration of radiocesium in the sample is obtained.

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The Overview of Our Research

Cited by 8 publications

References 11 publications

Radiation-Driven Migration: The Case of Minamisoma City, Fukushima, Japan, after the Fukushima Nuclear Accident

Radiation-Driven Migration: The Case of Minamisoma City, Fukushima, Japan, after the Fukushima Nuclear Accident

Plutonium concentrations link soil organic matter decline to wind erosion in ploughed soils of South Africa

Low-Background Shielding Box for Autoradiography of Environmental Samples and the α-, β-, and γ-ray Sensitivities of the Imaging Plates

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