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Sakai M, Watanabe M, Kanao Koshikawa M, Tanaka A, Takahashi A, Takechi S, Takagi M, Tsuji T, Tsuji H, Takeda T, Jo J, Tamaoki M, Hayashi S. Exploring simple ways to avoid collecting highly 137Cs-contaminated Aralia elata buds for the revival of local wild vegetable cultures. PLoS One 2024; 19:e0292206. [PMID: 38564644 PMCID: PMC10986964 DOI: 10.1371/journal.pone.0292206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 03/16/2024] [Indexed: 04/04/2024] Open
Abstract
Collection and cooking of wild vegetables have provided seasonal enjoyments for Japanese local people as provisioning and cultural ecosystem services. However, the Fukushima Daiichi Nuclear Power Plant accident in March 2011 caused extensive radiocesium contamination of wild vegetables. Restrictions on commercial shipments of wild vegetables have been in place for the last 10 years. Some species, including buds of Aralia elata, are currently showing radiocesium concentrations both above and below the Japanese reference level for food (100 Bq/kg), implying that there are factors decreasing and increasing the 137Cs concentration. Here, we evaluated easy-to-measure environmental variables (dose rate at the soil surface, organic soil layer thickness, slope steepness, and presence/absence of decontamination practices) and the 137Cs concentrations of 40 A. elata buds at 38 locations in Fukushima Prefecture to provide helpful information on avoiding collecting highly contaminated buds. The 137Cs concentrations in A. elata buds ranged from 1 to 6,280 Bq/kg fresh weight and increased significantly with increases in the dose rate at the soil surface (0.10-6.50 μSv/h). Meanwhile, the 137Cs concentration in A. elata buds were not reduced by decontamination practices. These findings suggest that measuring the latest dose rate at the soil surface at the base of A. elata plants is a helpful way to avoid collecting buds with higher 137Cs concentrations and aid in the management of species in polluted regions.
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Affiliation(s)
- Masaru Sakai
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, Miharu, Fukushima, Japan
| | - Mirai Watanabe
- National Institute for Environmental Studies, Regional Environmental Conservation Division, Tsukuba, Ibaraki, Japan
| | - Masami Kanao Koshikawa
- National Institute for Environmental Studies, Regional Environmental Conservation Division, Tsukuba, Ibaraki, Japan
| | - Asuka Tanaka
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, Miharu, Fukushima, Japan
| | - Akiko Takahashi
- National Institute for Environmental Studies, Regional Environmental Conservation Division, Tsukuba, Ibaraki, Japan
| | - Seiichi Takechi
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, Miharu, Fukushima, Japan
| | - Mai Takagi
- National Institute for Environmental Studies, Health and Environmental Risk Division, Tsukuba, Ibaraki, Japan
| | - Takashi Tsuji
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, Miharu, Fukushima, Japan
| | - Hideki Tsuji
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, Miharu, Fukushima, Japan
| | - Toshimasa Takeda
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, Miharu, Fukushima, Japan
| | - Jaeick Jo
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, Miharu, Fukushima, Japan
| | - Masanori Tamaoki
- National Institute for Environmental Studies, Biodiversity Division, Tsukuba, Ibaraki, Japan
| | - Seiji Hayashi
- National Institute for Environmental Studies, Fukushima Regional Collaborative Research Center, Miharu, Fukushima, Japan
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Hayashi S, Watanabe M, Kanao Koshikawa M, Takada M, Takechi S, Takagi M, Sakai M, Tamaoki M. Explaining the variation in 137Cs aggregated transfer factor for wild edible plants as a case study on Koshiabura (Eleutherococcus sciadophylloides) buds. Sci Rep 2023; 13:14162. [PMID: 37644128 PMCID: PMC10465601 DOI: 10.1038/s41598-023-41351-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 08/24/2023] [Indexed: 08/31/2023] Open
Abstract
The aggregated transfer factor (Tag) is commonly used to represent the actual transfer of radiocesium from soil to wild edible plants, but the values have shown substantial variation since the Fukushima nuclear accident. To elucidate the factors causing this variation, we investigated the effects of spatial scale and vertical 137Cs distribution in the soil on the variation of Tag-137Cs values for one of the most severely contaminated wild edible plants, Eleutherococcus sciadophylloides Franch. et Sav. (Koshiabura). The variation in Tag-137Cs values was not reduced by direct measurement of 137Cs deposition in soil samples from the Koshiabura habitat, as a substitute for using spatially averaged airborne survey data at the administrative district scale. The 137Cs activity concentration in Koshiabura buds showed a significant positive correlation with the 137Cs inventories only in the organic horizon of soil from the Koshiabura habitat. The ratio of 137Cs inventories in the organic horizon to the total 137Cs deposition in soil exhibited substantial variation, especially in broad-leaved deciduous forests that Koshiabura primarily inhabits. This variation may be the cause of the wide range of Tag-137Cs values observed in Koshiabura buds when calculated from the total 137Cs deposition in soil.
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Affiliation(s)
- Seiji Hayashi
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan.
| | - Mirai Watanabe
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Masami Kanao Koshikawa
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Momo Takada
- National Institute of Advanced Industrial Science and Technology, 1‑1‑1 Higashi, Tsukuba, Ibaraki, 305‑8567, Japan
| | - Seiichi Takechi
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan
| | - Mai Takagi
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
| | - Masaru Sakai
- Fukushima Regional Collaborative Research Center, National Institute for Environmental Studies, 10-2 Fukasaku, Miharu, Fukushima, 963-7700, Japan
| | - Masanori Tamaoki
- National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki, 305-8506, Japan
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Shuryak I. Machine learning analysis of 137Cs contamination of terrestrial plants after the Fukushima accident using the random forest algorithm. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 241:106772. [PMID: 34768117 DOI: 10.1016/j.jenvrad.2021.106772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/29/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Radioactive contamination of terrestrial plants was extensively investigated and quantitatively modeled after the Fukushima nuclear power plant accident. This phenomenon, which is important for ecosystem functioning and protection of human health, is influenced by multiple factors, including plant species, time after the accident, and climate. Machine learning algorithms such as random forests (RF) have a record of strong performance on large multi-dimensional data sets, but, to our knowledge, combined data on post-Fukushima plant contamination with radionuclides were not yet subjected to a machine learning analysis. Here we performed such analysis on two large published data sets: (1) 137Cs activity concentrations in four common Japanese forest tree species. (2) Plant/soil 137Cs concentration ratios in multiple perennial plant species. The goal was to show the usefulness of machine learning for identifying and quantifying the main trends of 137Cs contamination in terrestrial plants. Each data set was split randomly into training and testing parts, RF was fitted and tuned on the training parts, and its performance was assessed on the testing parts by three metrics: coefficient of determination (R2), root mean squared error, and mean absolute error. Synthetic noise variables and the Boruta algorithm were used in a customized procedure to identify the most important predictor variables, which consistently outperformed random noise. Good agreement between observations and RF predictions (e.g. R2∼0.9 on testing data) was obtained on both data sets. The effects of the most important predictors (e.g. time after the accident, 137Cs land contamination level, and plant species) and interactions between them were quantified by partial dependence plots. These results of machine learning analyses of large data collections can help to complement previous modeling efforts, and to clarify the patterns of 137Cs contamination of plants after the Fukushima accident.
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Affiliation(s)
- Igor Shuryak
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th Street, VC-11-234/5, New York, NY, 10032, USA.
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Kanasashi T, Miura S, Hirai K, Nagakura J, Itô H. Relationship between the activity concentration of 137Cs in the growing shoots of Quercus serrata and soil 137Cs, exchangeable cations, and pH in Fukushima, Japan. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 220-221:106276. [PMID: 32560880 DOI: 10.1016/j.jenvrad.2020.106276] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
Incorporation of radiocesium by plants via root uptake appears to be affected by some of the exchangeable cations in the soil and/or pH of the soil. However, few studies have examined the relationship between 137Cs in trees and soil properties in the area surrounding the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) after the accident in March 2011. To elucidate the relationships between the root uptake of 137Cs by deciduous broadleaved trees and soil properties, we measured the activity concentration of 137Cs in the growing shoots of coppiced konara oak (Quercus serrata) grown after the FDNPP accident and the amounts of total 137Cs; exchangeable (ex-) 137Cs, ex-K, ex-Mg, and ex-Ca; and pH (H2O) in soils collected from 34 forest stands in Fukushima between December 2016 and May 2017. Ex-137Cs showed a positive linear relationship with the activity concentration of 137Cs in the growing konara oak shoots, whereas ln-transformed ex-K, ex-Mg, ex-Ca, and pH (H2O) showed negative linear relationships with ln-transformed 137Cs activity concentrations in the growing shoots. However, only ex-137Cs and ex-K were identified as significant factors determining the activity concentration of 137Cs in konara oak according to multiple regression methods and a model selection using Akaike information criterion; ex-K had a stronger influence on the activity concentration of 137Cs in konara oak than ex-137Cs. In the present study, we demonstrated that soil ex-K negatively and non-linearly alters 137Cs activity concentration in deciduous broadleaved trees. We also noted that the relationship between 137Cs in deciduous broadleaved trees and soil ex-K in forests without K fertilization was similar to the relationships between 137Cs in other plants and ex-K in K-fertilized lands reported in previous studies of the FDNPP accident.
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Affiliation(s)
- Tsutomu Kanasashi
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Satoru Miura
- Center for Forest Restoration and Radioecology, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan.
| | - Keizo Hirai
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Junko Nagakura
- Department of Forest Soils, Forestry and Forest Products Research Institute, 1 Matsunosato, Tsukuba, Ibaraki, 305-8687, Japan
| | - Hiroki Itô
- Hokkaido Research Center, Forestry and Forest Products Research Institute, 7 Hitsujigaoka, Toyohira, Sapporo, Hokkaido, 062-8516, Japan
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Ozaki H, Inamochi R, Takahashi H, Takahashi H, Hara Y, Tokumaru T, Watai C, Gomi T, Watanabe I. Road Dust as a Significant Radiocesium Transporter from Land to River. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2020; 79:39-48. [PMID: 32350556 DOI: 10.1007/s00244-020-00738-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 04/21/2020] [Indexed: 06/11/2023]
Abstract
This study made it clear that road dust plays an important role for Cs-137 dynamics emitted by the Fukushima Daiichi nuclear power plant accident. It was proved from the Cs-137 and heavy metals determination in road dust, drainage gutter sediment beside pavement, and riverbed sediment around the inflow point of the gutter. Road dust and drainage gutter sediment contained significantly higher concentrations of Cs-137 and Cr, Ni, Cu, Zn, Mo, Cd, Sn, Sb, and Pb than riverbed sediment. These heavy metals are typically enriched in road dust in general and originate in anthropogenic sources. Concentrations of Cs-137 and the heavy metals were higher in riverbed sediments at the inflow point of drainage than in non-inflow points. Drainage gutter sediments exhibited Cs-137 and heavy metal accumulation at the downmost of the gutter, which is the inflow point into the river. Accordingly, distribution of Cs-137 and the heavy metals concentrations were consistent with each other. Moreover, the concentrations of Cs-137 and heavy metals were correlated positively and significantly, with different proportions between sampling sites but similar between sample type and survey date. This indicates that the discharge of Cs-137 and heavy metals is characteristic of the features of the locations, such as Cs-137 and heavy metals concentrations, (micro-) topography, structure of the road and gutter, pavement area, traffic density, and so on. We conclude that road dust is a major medium of Cs-137 transport from land into aquatic ecosystems.
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Affiliation(s)
- Hirokazu Ozaki
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan.
- Fukushima Branch, National Institute for Environmental Studies, Japan, 10-2 Fukasaku, Miharu, Tamura District, Fukushima, 963-7700, Japan.
| | - Riko Inamochi
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Hiroyuki Takahashi
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Hikaru Takahashi
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yuta Hara
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Takashi Tokumaru
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Chie Watai
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Takashi Gomi
- Department of International Environmental and Agricultural Science, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Izumi Watanabe
- Department of Environmental Science on Biosphere, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
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Shuryak I. Review of resistance to chronic ionizing radiation exposure under environmental conditions in multicellular organisms. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2020; 212:106128. [PMID: 31818732 DOI: 10.1016/j.jenvrad.2019.106128] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 12/02/2019] [Accepted: 12/03/2019] [Indexed: 06/10/2023]
Abstract
Ionizing radiation resistance occurs among many phylogenetic groups and its mechanisms remain incompletely understood. Tolerances to acute and chronic irradiation do not always correlate because different mechanisms may be involved. The radioresistance phenomenon becomes even more complex in the field than in the laboratory because the effects of radioactive contamination on natural populations are intertwined with those of other factors, such as bioaccumulation of radionuclides, interspecific competition, seasonal variations in environmental conditions, and land use changes due to evacuation of humans from contaminated areas. Previous reviews of studies performed in radioactive sites like the Kyshtym, Chernobyl, and Fukushima accident regions, and of protracted irradiation experiments, often focused on detecting radiation effects at low doses in radiosensitive organisms. Here we review the literature with a different purpose: to identify organisms with high tolerance to chronic irradiation under environmental conditions, which maintained abundant populations and/or outcompeted more radiosensitive species at high dose rates. Taxa for which consistent evidence for radioresistance came from multiple studies conducted in different locations and at different times were found among plants (e.g. willow and birch trees, sedges), invertebrate and vertebrate animals (e.g. rotifers, some insects, crustaceans and freshwater fish). These organisms are not specialized "extremophiles", but tend to tolerate broad ranges of environmental conditions and stresses, have small genomes, reproduce quickly and/or disperse effectively over long distances. Based on these findings, resistance to radioactive contamination can be examined in a more broad context of chronic stress responses.
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Affiliation(s)
- Igor Shuryak
- Center for Radiological Research, Columbia University Irving Medical Center, 630 West 168th Street, VC-11-234/5, New York, NY, USA.
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Translocation of cesium in the branches of Japanese cedar (Cryptomeria japonica) and Konara oak (Quercus serrata). J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-019-06996-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Ayabe Y, Yoshida T, Kanasashi T, Hayashi A, Fukushi A, Hijii N, Takenaka C. Web-building spider Nephila clavata (Nephilidae: Arachnida) can represent 137Cs contamination of arthropod communities and bioavailable 137Cs in forest soils at Fukushima, Japan. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 687:1176-1185. [PMID: 31412453 DOI: 10.1016/j.scitotenv.2019.06.158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/22/2019] [Accepted: 06/10/2019] [Indexed: 06/10/2023]
Abstract
Large areas of Fukushima's forests were contaminated with radiocesium (137Cs) after the Fukushima Dai-ichi Nuclear Power Plant accident. Most of the contaminated forests have not been decontaminated, and bioavailable 137Cs is likely to circulate within the forest environment's food web. Nephila clavata (Nephilidae: Arachnida) is a top predator in the forest arthropod community, and this web-building spider potentially consumes many arthropod species presented in the grazing and detrital food chains. We tested whether 137Cs in the spider could serve as a proxy for 137Cs contamination of these arthropod communities. We also examined whether N. clavata could serve as a proxy for soil bioavailable 137Cs. Nephila clavata was similarly or more contaminated with 137Cs compared with lower-trophic-level arthropods such as herbivores and other predators at the same trophic level. Thus, the 137Cs activity of N. clavata could represent the extent to which the arthropod community was contaminated with 137Cs. Data from nine 137Cs-contaminated sites in Fukushima showed a significant positive correlation between soil bioavailable 137Cs and N. clavata's 137Cs activity05 but the coefficient of determination was only moderate (R2 = 0.43), suggesting that N. clavata is only a weak proxy of soil bioavailable 137Cs. Our results also showed that the bioavailable fraction of 137Cs in Fukushima was strongly correlated with the total inventory and that the K and Na contents of the soil determined the soil-to-spider transfer factor for 137Cs and the 137Cs activity in N. clavata, respectively. These results improve our understanding of 137Cs transfer from the soil to arthropod species.
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Affiliation(s)
- Yoshiko Ayabe
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Tomohiro Yoshida
- Field Science Center, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509, Japan.
| | - Tsutomu Kanasashi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Akane Hayashi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Akihisa Fukushi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Naoki Hijii
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Chisato Takenaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
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Luo Q, Jiang D, Hou D, Chen W, Hu X, He Y. Effective adsorption of metal ions by modified clinoptilolite zeolite from simulated radioactive solution. J Radioanal Nucl Chem 2019. [DOI: 10.1007/s10967-018-6383-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Ogata Y, Itadzu H, Kojima S. Determination of 134Cs activity with the sum-peak method using a well-type germanium detector. J Radioanal Nucl Chem 2018. [DOI: 10.1007/s10967-018-5784-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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12
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Ko JA, Furuta N, Lim HB. Quantitative mapping of elements in basil leaves (Ocimum basilicum) based on cesium concentration and growth period using laser ablation ICP-MS. CHEMOSPHERE 2018; 190:368-374. [PMID: 29024882 DOI: 10.1016/j.chemosphere.2017.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 09/20/2017] [Accepted: 10/01/2017] [Indexed: 06/07/2023]
Abstract
Quantitative elemental mapping of metallic pollutants in sweet basil was studied by laser ablation (LA)-ICP-MS. For this, the sweet basil was cultivated in Hoagland nutrient solution spiked with 100 and 1000 ng mL-1 of Cs for 10-60 days. Then, the Cs distribution in collected leaves was determined by LA-ICP-MS using lab-synthesized standard pellets based on NIST 1573a tomato leaves. For comparison, S, Ca, and K were also simultaneously determined in this measurement with a13C+ signal from the leaves as an internal standard. The obtained calibration curves showed linear coefficient of determination (R2) of 0.991 for K and 0.999 for Cs. The concentration of Cs measured in the basil leaves increased with growth period and pollutant concentration, and accumulation followed the order of leaf margin, petiole, midrib, and veins. Although no visible symptom was detected, significant suppression of the growth rate was observed due to the presence of high-concentration Cs. The experimental model demonstrated herein showed potential for studying the influence of radioactive pollutants on plants and other organisms in the food chain.
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Affiliation(s)
- Jung Aa Ko
- Department of Chemistry, Dankook University, Yongin-si, Gyeonggi-do 448-701, South Korea; Future Environmental Research Center, Korea Institute of Toxicology, Jinju 660-844, South Korea
| | - Naoki Furuta
- Department of Applied Chemistry, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Bunkyo, Tokyo 112-8551, Japan
| | - Heung Bin Lim
- Department of Chemistry, Dankook University, Yongin-si, Gyeonggi-do 448-701, South Korea.
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Sato F, Okumura T, Kato Y, Murata I, Iida T. Development of beta ray scanner for imaging foliar uptake of radiocesium. RADIATION DETECTION TECHNOLOGY AND METHODS 2017. [DOI: 10.1007/s41605-017-0019-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Ayabe Y, Hijii N, Takenaka C. Effects of local-scale decontamination in a secondary forest contaminated after the Fukushima nuclear power plant accident. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2017; 228:344-353. [PMID: 28551564 DOI: 10.1016/j.envpol.2017.05.041] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 05/11/2017] [Accepted: 05/17/2017] [Indexed: 06/07/2023]
Abstract
We investigated whether local-scale decontamination (removal of the litter layer, superficial soil layer, and understory) in a secondary forest contaminated by the Fukushima nuclear power plant accident reduced 137Cs contamination of the soil and litter. We also measured 137Cs concentrations in plants and in the web-building spider Nephila clavata (Nephilidae: Arachnida), as an indicator species, to examine 137Cs contamination in arthropods. One month after decontamination, the total 137Cs contamination (soil + litter) was reduced by 20% (100 kBq·m-2) relative to that in an adjacent untreated (i.e., contaminated) area, which was however not statistically significant. Four months after decontamination, 137Cs in the decontaminated area had increased to a level similar to those in the untreated area, and the air radiation dose in the decontaminated area was about 2.1 μSv·h-1, significantly higher than that in the untreated area (1.9 μSv·h-1). This may have been attributed to a torrential rain event. Although no statistically significant reduction was observed, most spiders had a lower 137Cs contamination than that before the decontamination. This implied that the decontamination may have reduced 137Cs transfer from soil via litter to N. clavata through the detrital food chains, but may not have reduced the amount of 137Cs transfer through grazing food chains because the concentration of 137Cs in living tree leaves was not reduced by the decontamination. In autumn, about 2 kBq·m-2 of 137Cs was supplied from foliage to the ground by litterfall. The results suggested that removal of the litter and superficial soil layers in a contaminated forest may be ineffective. The present study suggests that the local-scale decontamination in a secondary forest had no effect on the reduction of 137Cs contamination in the treated area.
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Affiliation(s)
- Yoshiko Ayabe
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Naoki Hijii
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
| | - Chisato Takenaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
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Naulier M, Eyrolle-Boyer F, Boyer P, Métivier JM, Onda Y. Particulate organic matter in rivers of Fukushima: An unexpected carrier phase for radiocesiums. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 579:1560-1571. [PMID: 27923577 DOI: 10.1016/j.scitotenv.2016.11.165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 11/23/2016] [Accepted: 11/23/2016] [Indexed: 06/06/2023]
Abstract
The role of particulate organic matter in radiocesium transfers from soils to rivers was investigated in areas contaminated by the Fukushima Daiichi Nuclear Power Plant accident. Suspended and deposited sediments, filtered water, macro organic debris and dead leaves were sampled along the six most contaminated coastal river catchments of the Fukushima prefecture in the early autumns 2013 and 2014. Radiocesium concentrations of river samples and total organic carbon concentrations in suspended and deposited sediments were measured. Radiocesium concentrations of suspended and deposited sediments were significantly correlated to 137Cs inventories in soils and total organic carbon. The distributions of radiocesium between the organic and mineral phases of both types of sediment were assessed by using a modelling approach. The results suggest that, during the early autumn season, the organic fraction was the main phase that carried the radiocesiums in deposited sediments and in suspended sediments for suspended loads <25mg·L-1. For higher suspended loads like those occurring during typhoon periods, the mineral fraction was the main carrier phase. Thus, high apparent distribution coefficient values noted by various authors in Fukushima could be attributed to the high radiocesium contents of particulate organic matter. Since it is well known that organic compounds generally do not significantly adsorb radiocesium onto specific sites, several hypotheses are suggested: 1) Radiocesiums may have been absorbed into organic components at the early stage of atmospheric radioactive deposits and/or later due to biomass recycling and 2) Those elements would be partly carried by glassy hot particles together with organic matter transported by rivers in Fukushima. Both hypotheses would lead to conserve the amount of radiocesiums associated with particles during their transfers from the contaminated areas to the marine environment. Finally, such organically bound radiocesium would lead to significant deliveries of bioavailable radiocesium for living organisms at Fukushima.
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Affiliation(s)
- Maud Naulier
- Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV, SERIS/LRTE, SESURE/LEREN, BP 3, 13115 Saint-Paul-lez-Durance, France.
| | - Frédérique Eyrolle-Boyer
- Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV, SERIS/LRTE, SESURE/LEREN, BP 3, 13115 Saint-Paul-lez-Durance, France
| | - Patrick Boyer
- Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV, SERIS/LRTE, SESURE/LEREN, BP 3, 13115 Saint-Paul-lez-Durance, France
| | - Jean-Michel Métivier
- Institut de Radioprotection et de Sureté Nucléaire (IRSN), PRP-ENV, SERIS/LRTE, SESURE/LEREN, BP 3, 13115 Saint-Paul-lez-Durance, France
| | - Yuichi Onda
- Center of Research in Isotopes and Environmental Dynamics (CRIED), Tsukuba, Japan
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16
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Sugiura Y, Ozawa H, Umemura M, Takenaka C. Soil amendments effects on radiocesium translocation in forest soils. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2016; 165:286-295. [PMID: 27835846 DOI: 10.1016/j.jenvrad.2016.10.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Revised: 07/14/2016] [Accepted: 10/20/2016] [Indexed: 06/06/2023]
Abstract
We conducted an experiment to investigate the potential of phytoremediation by soil amendments in a forest area. To desorb radiocesium (137Cs) from variable charges in the soil, ammonium sulfate (NH4+) and elemental sulfur (S) (which decrease soil pH) were applied to forest soil collected from contaminated area at a rate of 40 and 80 g/m2, respectively. A control condition with no soil treatment was also considered. We defined four groups of aboveground conditions: planted with Quercus serrata, planted with Houttuynia cordata, covered with rice straw as litter, and unplanted/uncovered (control). Cultivation was performed in a greenhouse with a regular water supply for four months. Following elemental sulfur treatment, soil pH values were significantly lower than pH values following ammonium sulfate treatment and no treatment. During cultivation, several plant species germinated from natural seeds. No clear differences in aboveground tissue 137Cs concentrations in planted Q. serrata and H. cordata were observed among the treatments. However, aboveground tissue 137Cs concentration values in the germinated plants following elemental sulfur treatment were higher than the values following the ammonium sulfate treatment and no treatment. Although biomass values for Q. serrata, H. cordata, and germinated plants following elemental sulfur treatment tended to be low, the total 137Cs activities in the aboveground tissue of germinated plants were higher than those following ammonium sulfate treatment and no treatment in rice straw and unplanted conditions. Although no significant differences were observed, 137Cs concentrations in rice straw following ammonium sulfate and elemental sulfur treatments tended to be higher than those in the control case. The results of this study indicate that elemental sulfur lowers the soil pH for a relatively long period and facilitates 137Cs translocation to newly emerged and settled plants or litter, but affects plant growth in large concentrations and/or anaerobic conditions. Combining elemental sulfur application with forest management practices, such as mowing and thinning, could be a suitable method of decontamination of the forest environment.
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Affiliation(s)
- Yuki Sugiura
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
| | - Hajime Ozawa
- Fukushima Prefectural Forestry Research Centre, Koriyama, Fukushima 963-0112, Japan.
| | - Mitsutoshi Umemura
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
| | - Chisato Takenaka
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
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