Vertical Migration of Radiocesium Fallout in Soil in Fukushima

Shiozawa, Sho

doi:10.1007/978-4-431-54328-2_6

Cited by 20 publications

(17 citation statements)

References 4 publications

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“…2) agrees with other studies in orchards and undisturbed fields (Ohno et al 2012;Shiozawa 2013;Sato 2014a). The correlation between radiocesium concentration in the mature fruit and in the topsoil layer is, therefore, likely due to the fact that radiocesium is strongly retained in soil.…”

Section: Discussionsupporting

confidence: 91%

Radiocesium transfer into the fruit of deciduous fruit trees contaminated during dormancy

Sato

Takata

Tanoi

et al. 2014

Soil Science and Plant Nutrition

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Following the accident at the Tokyo Electric Power Company, Fukushima Daiichi Nuclear Power Plant (FDNPP), radiocesium ( 134 Cs + 137 Cs) concentrations in deciduous mature fruits were determined in orchards in the northern area of Fukushima Prefecture. At the time of the nuclear accident, most deciduous fruit trees were in the dormant stage prior to bud burst. To evaluate the relationship between radiocesium deposition in the soil and fruit contamination, radiocesium concentrations were measured from the 5-cm topsoil and from six fruit species across 17 orchards in 2011. The vertical distribution of radiocesium in the topsoil (0-30 cm in depth) and its spatial distribution in the 5-cm topsoil underlying the tree canopy of a peach, Prunus persica (L.) Batsh, orchard ("Akatsuki" cultivar) were also investigated. Significant correlations between the radiocesium concentration in the mature fruit and that in the 5-cm topsoil layer were observed for the 17 orchards as well as for the trees of the peach orchard. However, 93% of the 137 Cs found in the 30-cm soil core was retained within the top 3 cm of the soil in the peach orchard. Considering the profile of the root of this deciduous fruit tree, we assumed a negligible level of radiocesium uptake via the roots. However, the possibility of inward migration via the bark was undeniable, because some radiocesium adhered to the tree canopy before bud burst while depositing on the soil surface. Additionally, transfer factors for peach and grape, hybrid of Vitis labrusca L. and Vitis vinifera L., from young, uncontaminated trees cultivated with contaminated soil were lower than those previously reported.Key words: Fukushima Daiichi nuclear accident, inward migration via the bark, radiocesium in fruits, vertical distribution in orchard soil.

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Section: Discussionsupporting

confidence: 91%

Radiocesium transfer into the fruit of deciduous fruit trees contaminated during dormancy

Sato

Takata

Tanoi

et al. 2014

Soil Science and Plant Nutrition

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“…3 Immediately after the FDNPP accident, Tanaka et al (2013c) reported that the radiocesium was water soluble, though once radiocesium adsorbed on to soil and rock particles it quickly became essentially insoluble. The increase in insolubility was also reported by Shiozawa (2013) who indicated that the strong fixation of radiocesium to clay particles during the initial 2e3 months after the accident reduced the migration of radiocesium in the depth profile. The strong fixation to clay particles was again reported by Saito et al (2014) and Kikawada et al (2014) who indicated that virtually no radiocesium was extractable from soil samples with simple water solutions.…”

Section: Soil Depositionsupporting

confidence: 72%

Radiocesium transfer from hillslopes to the Pacific Ocean after the Fukushima Nuclear Power Plant accident: A review

Evrard

Laceby

Lepage

et al. 2015

Journal of Environmental Radioactivity

159

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The devastating tsunami triggered by the Great East Japan Earthquake on March 11, 2011 inundated the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) resulting in a loss of cooling and a series of explosions releasing the largest quantity of radioactive material into the atmosphere since the Chernobyl nuclear accident. Although 80% of the radionuclides from this accidental release were transported over the Pacific Ocean, 20% were deposited over Japanese coastal catchments that are subject to frequent typhoons. Among the radioisotopes released during the FDNPP accident, radiocesium ((134)Cs and (137)Cs) is considered the most serious current and future health risk for the local population. The goal of this review is to synthesize research relevant to the transfer of FDNPP derived radiocesium from hillslopes to the Pacific Ocean. After radiocesium fallout deposition on vegetation and soils, the contamination may remain stored in forest canopies, in vegetative litter on the ground, or in the soil. Once radiocesium contacts soil, it is quickly and almost irreversibly bound to fine soil particles. The kinetic energy of raindrops instigates the displacement of soil particles, and their bound radiocesium, which may be mobilized and transported with overland flow. Soil erosion is one of the main processes transferring particle-bound radiocesium from hillslopes through rivers and streams, and ultimately to the Pacific Ocean. Accordingly this review will summarize results regarding the fundamental processes and dynamics that govern radiocesium transfer from hillslopes to the Pacific Ocean published in the literature within the first four years after the FDNPP accident. The majority of radiocesium is reported to be transported in the particulate fraction, attached to fine particles. The contribution of the dissolved fraction to radiocesium migration is only relevant in base flows and is hypothesized to decline over time. Owing to the hydro-meteorological context of the Fukushima region, the most significant transfer of particulate-bound radiocesium occurs during major rainfall and runoff events (e.g. typhoons and spring snowmelt). There may be radiocesium storage within catchments in forests, floodplains and even within hillslopes that may be remobilized and contaminate downstream areas, even areas that did not receive fallout or may have been decontaminated. Overall this review demonstrates that characterizing the different mechanisms and factors driving radiocesium transfer is important. In particular, the review determined that quantifying the remaining catchment radiocesium inventory allows for a relative comparison of radiocesium transfer research from hillslope to catchment scales. Further, owing to the variety of mechanisms and factors, a transdisciplinary approach is required involving geomorphologists, hydrologists, soil and forestry scientists, and mathematical modellers to comprehensively quantify radiocesium transfers and dynamics. Characterizing radiocesium transfers from hillslopes to the Pacific Ocean is necess...

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“…2). Studies in northeastern Japan after the Fukushima accident showed high radioactive Cs contents in the top layer of untilled arable soils (Koarashi et al 2012;Yamaguchi et al 2012;Shiozawa 2013). Many studies conducted after the Chernobyl accident indicated that vertical migration of radioactive Cs was very slow, and most radioactive Cs was present in the upper soil layers (e.g., Almgren and Isaksson 2006).…”

Section: Radioactive Cs In Pastures 795mentioning

confidence: 99%

Distribution of radioactive cesium in soil and its uptake by herbaceous plants in temperate pastures with different management after the Fukushima Dai-Ichi Nuclear Power Station accident

Ogura

Suzuki

Saitô

2014

Soil Science and Plant Nutrition

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The accident at Fukushima Dai-Ichi Nuclear Power Station (NPS) extensively contaminated the agricultural land in the Tohoku region of Japan with radioactive cesium [sum of cesium-134 ( 134 Cs) and cesium-137 ( 137 Cs)]. We evaluated the status of radioactive cesium (Cs) contamination in soil and plants at the Field Science Center of Tohoku University, northern Miyagi prefecture, 150 km north of the NPS. In seven pastures with different management, we examined: (1) the distribution of radioactive Cs in soil, (2) the concentration of radioactive Cs in various herbaceous plant species and (3) the change in radioactive Cs content of plants as they matured. We collected samples of litter, root mat layer (root mat soil and plant roots), and subsurface soil (0-5 cm beneath the root mat) at two to three locations in each pasture in December 2011 and May 2012. The aboveground parts of herbaceous plants (four grasses, two legumes, and one forb species) were collected from May 9 to June 20, 2012, at 14-d intervals, from one to five fixed sampling locations in each pasture. The distribution of radioactive Cs in soil differed among pastures to some degree: a large proportion of radioactive Cs was distributed in the root mat layer. Pasture management greatly influenced the radioactive Cs content of herbaceous plants (p < 0.001); plant species had less influence. Radioactive Cs content was highest (> 3 kBq kg −1 dry weight) on May 9 and significantly decreased with maturity (p < 0.001) for most of the pastures, whereas it remained low (0.04-0.18 kBq kg −1 dry weight) throughout the measurement period in the pasture where composted cattle manure was applied. The soil-to-plant transfer factor was negatively correlated to pH(H 2 O) (R 2 = 0.783, p < 0.001) and exchangeable K content (R 2 = 0.971, p < 0.001) of root mat soils, which suggests that surface application of composted cattle manure reduces plant uptake of radioactive Cs by increasing the exchangeable K content of the soil. The radioactive Cs content of plants decreased with plant maturity; its degree of decrease (May 9 to June 6) was smaller in legumes (80.6%) than grasses (55.5%) and the forb (58.6%). Radioactive Cs content decreased with plant maturity; also, the proportion remaining in the aboveground plant was higher in legumes (80.6%) than grasses (55.5%) and the forb (58.6%).

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Vertical Migration of Radiocesium Fallout in Soil in Fukushima

Cited by 20 publications

References 4 publications

Radiocesium transfer into the fruit of deciduous fruit trees contaminated during dormancy

Radiocesium transfer into the fruit of deciduous fruit trees contaminated during dormancy

Radiocesium transfer from hillslopes to the Pacific Ocean after the Fukushima Nuclear Power Plant accident: A review

Distribution of radioactive cesium in soil and its uptake by herbaceous plants in temperate pastures with different management after the Fukushima Dai-Ichi Nuclear Power Station accident

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