Radiocesium in Stem, Branch and Leaf of &lt;i&gt;Cryptomeria japonica&lt;/i&gt; and &lt;i&gt;Pinus densiflora&lt;/i&gt; Trees:

Masumori, Masaya; Nogawa, Norio; Sugiura, Shin; Tange, Takeshi

doi:10.4005/jjfs.97.51

Cited by 13 publications

(9 citation statements)

References 3 publications

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“…Radioactive cesium ( 137 Cs) dispersed into the atmosphere by a nuclear weapon test or power plant accident is transferred into trees mainly by two pathways, namely, foliar uptake and root uptake [1,2]. A major part of the foliar uptake of 137 Cs is assumed to occur shortly after a 137 Cs deposition event, when the fraction of dissolved 137 Cs in throughfall and precipitation is high [3], and can be the major source of initial 137 Cs input to trees that have needles or leaves at the time of the deposition event [4]. Subsequently, as the amount of 137 Cs in throughfall decreases exponentially with time [3,5], root uptake becomes the dominant source of 137 Cs input to trees over the long term [1].…”

Section: Introductionmentioning

confidence: 99%

Tracing radioactive cesium in stem wood of three Japanese conifer species 3 years after the Fukushima Dai-ichi Nuclear Power Plant accident

et al. 2020

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To understand the dynamics of accident-derived radioactive cesium (137 Cs) in stem wood that had a substantial amount of heartwood at the time of the Fukushima Dai-ichi Nuclear Power Plant accident, the radial and vertical distributions of 137 Cs activity concentration in stem wood of Japanese cedar (Cryptomeria japonica), cypress (Chamaecyparis obtusa), and larch (Larix kaempferi) were investigated. In addition, the natural distribution of stable cesium (133 Cs), rubidium (85 Rb), and potassium (39 K) concentrations was analyzed to determine the characteristics of 137 Cs distribution. Wood disks were collected from the tree stems of six cedars, three cypresses, and two larches at multiple heights in 2014, and the concentrations were measured every 2 cm in the radial direction. 137 Cs distribution in stem wood differed among tree species, sampling site, and vertical position of the stem within a tree. Statistical analyses suggested that the radial distribution of 137 Cs within the heartwood can be explained by the heartwood moisture content and the distance from the treetop, regardless of species, while the distribution between sapwood and heartwood was dependent on the heartwood cross-sectional area and was additionally different between larch and other species. Similarly, the heartwood/sapwood concentration ratios of stable alkali metals differed between larch and the other species. In the larch, the ratio was ca. 0.5 for all elements, but the ratio was over 1.0 and differed among elements in the other species. Consequently, the species-specific difference in the distribution of 137 Cs between sapwood and heartwood was considered to be due to different activity levels of radial transport toward the heartwood. The radial variation pattern of the 137 Cs/ 133 Cs concentration ratio showed that less 137 Cs was transferred to the inner heartwood compared with the 133 Cs distribution pattern in many trees; however, there was also a tree in which 137 Cs was excessively transferred to the inner heartwood compared with the 133 Cs distribution pattern. Such patterns may result from a combination of significant foliar uptake of 137 Cs and poor root uptake after the accident, in addition to the high moisture content of the heartwood.

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Section: Introductionmentioning

confidence: 99%

Tracing radioactive cesium in stem wood of three Japanese conifer species 3 years after the Fukushima Dai-ichi Nuclear Power Plant accident

et al. 2020

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“…Many studies in the Fukushima contaminated area related to early 137 Cs distribution in the Japanese forest ecosystems21516171819. Most of these studies began immediately after the accident (main data from 2011 to 2012) and showed that for the evergreen species, interception by canopies was very high (60–90%) due to high canopy closure20.…”

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confidence: 99%

Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

Coppin

Hurtevent

Loffredo

et al. 2016

Sci Rep

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Our study focused on radiocaesium (137Cs) partitioning in forests, three vegetation periods after the Fukushima Daiichi nuclear power plant accident. 137Cs distribution in forest components (organic and mineral soil layers as well as tree compartments: stem, bark, needles, branches and roots) was measured for two Japanese cedar stand ages (17 and 33 years old). The results showed that around 85% of the initial deposit was found in the forest floor and topsoil. For the youngest stand almost 70% of the deposit is present in the forest floor, whereas for the oldest stand 50% is present in the 0–3 cm mineral soil layer. For trees, old and perennial organs (including dead and living needles and branches, litter fall and outer bark) directly exposed to the fallout remained the most contaminated. The crown concentrated 61–69% of the total tree contamination. Surprisingly the dead organs concentrated 25 ± 9% (young cedars) to 36 ± 20% (mature cedar) of the trees’ residual activity, highlighting the importance of that specific compartment in the early post-accident phase for Japanese cedar forests. Although the stem (including bark) represents the highest biomass pool, it only concentrates 3.3% and 4.6% of the initial 137Cs deposit for mature and young cedars, respectively.

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“…9). 10,32) Although the amount of radioactivity that moved into the heartwood differed along the height of the trunk, the contamination inside the tree was not caused by the transportation of 134 Cs and 137 Cs from the roots. The active part of the roots for most trees is at least 20–30 cm below the surface of the soil, and no radiocesium is present at this depth, which suggests that the roots could not absorb 134 Cs and 137 Cs.…”

Section: Forest Contaminationmentioning

confidence: 99%

Agricultural aspects of radiocontamination induced by the Fukushima nuclear accident — A survey of studies by the Univ. of Tokyo Agricultural Dept. (2011–2016)

Nakanishi

2018

Proceedings of the Japan Academy. Ser. B: Physical and Biologic

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Immediately after the Fukushima nuclear power plant accident, a team of 40–50 researchers at the Graduate School of Agricultural and Life Sciences at the University of Tokyo began to analyze the behavior of radioactive materials in the fallout regions. The fallout has remained in situ and become strongly adsorbed within the soil over time. 137Cs was found to bind strongly to the fine clay, weathered biotite, and organic matter in the soil; therefore, it has not mobilized from mountainous regions, even after heavy rainfall. In farmland, the quantity of 137Cs in the soil absorbed by crop plants was small. The downward migration of 137Cs in soil is now estimated at 1–2 mm/year. The intake of 137Cs by trees occurred through the bark and not from the roots. This report summarizes the findings of research across a wide variety of agricultural specialties.

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Radiocesium in Stem, Branch and Leaf of <i>Cryptomeria japonica</i> and <i>Pinus densiflora</i> Trees:

Cited by 13 publications

References 3 publications

Tracing radioactive cesium in stem wood of three Japanese conifer species 3 years after the Fukushima Dai-ichi Nuclear Power Plant accident

Tracing radioactive cesium in stem wood of three Japanese conifer species 3 years after the Fukushima Dai-ichi Nuclear Power Plant accident

Radiocaesium partitioning in Japanese cedar forests following the “early” phase of Fukushima fallout redistribution

Agricultural aspects of radiocontamination induced by the Fukushima nuclear accident — A survey of studies by the Univ. of Tokyo Agricultural Dept. (2011–2016)

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