Factors affecting vertical distribution of Fukushima accident-derived radiocesium in soil under different land-use conditions

Koarashi, Jun; Atarashi-Andoh, Mariko; Matsunaga, Takeshi; Satō, Tsutomu; Nagao, Seiya; Nagai, Hiroki

doi:10.1016/j.scitotenv.2012.05.041

Cited by 179 publications

(142 citation statements)

References 28 publications

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“…A major part of radiocesium deposited on the ground surface is present at the surface to 5 cm depth (MEXT, 2012a;Koarashi et al, 2012). Chemical extraction of 134 Cs and 137 Cs from selected soil samples has revealed that both radionuclides in the soil are only slightly water-soluble.…”

Section: Introductionmentioning

confidence: 99%

Export of 134 Cs and 137 Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

et al. 2013

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Abstract. At stations on the Natsui River and the Same River in Fukushima Prefecture, Japan, effects of a heavy rain event on radiocesium export were studied after Typhoon Roke during 21-22 September 2011, six months after the Fukushima Dai-ichi Nuclear Power Plant accident. Radioactivity of 134 Cs and 137 Cs in river waters was 0.009-0.098 Bq L −1 in normal flow conditions during July-September 2011, but it increased to 0.85 Bq L −1 in high flow conditions because of heavy rains occurring with the typhoon. The particulate fractions of 134 Cs and 137 Cs were 21-56 % of total radiocesium in the normal flow condition, but were close to 100 % after the typhoon. These results indicate that the pulse input of radiocesium associated with suspended particles from land to coastal ocean occurred because of the heavy rain event. Export flux of 134 Cs and 137 Cs attributable to the heavy rain accounts for 30-50 % of the annual radiocesium flux from inland to coastal ocean region in 2011. Results show that rain events are one factor contributing to the transport and dispersion of radiocesium in river watersheds and coastal marine environments.

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Section: Introductionmentioning

confidence: 99%

Export of 134 Cs and 137 Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

et al. 2013

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“…Heterogeneity of Cs-137 distribution within plough layer of arable soils has escaped the attention of the researchers. Even with experimental evidence in some studies presented in tables and figures the possible reasons are not discussed as a rule [14][15][16]. We suppose that the observed variability of the Cs-137 vertical distribution within Ap + Aop horizons of cultivated chernozems of the Plavsk radioactive hotspot can be most reasonably explained by the combination of the two factors.…”

Section: Vertical Profile Depth Distribution Of Cs-137 Within Plough mentioning

confidence: 87%

Homo/Heterogeneity of Cs-137 Vertical Distribution Within Plough Horizons of Cultivated Chernozems – 30 Years After Chernobyl Accident

Paramonova¹,

Belyaev²,

Komissarova³

et al. 2017

RadJ

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Abstract. Vertical distribution of Cs-137 in cultivated chernozems of the Plavsk radioactive hotspot has been investigated, with the emphasis on the plough horizon. It is shown that the commonly expected complete homogeneity of the isotope vertical distribution within the plough and old-plough horizons of cultivated chernozems is not always achieved. Incomplete homogeneity can be explained by the application of different cultivation techniques for various crops within the crop rotation system employed. Important observation is that in cases of relatively shallow cultivation (such as disking to 12-15 cm depth) the largest root biomass content remains within the upper 10 cm layer, while maximum Cs-137 content is shifted downwards to underplough layer at 10-20 cm depths. At the same time, traditional cultivation with plough layer rotation and mixing to the 20-25 cm depth results in more uniform Cs-137 distribution through the plough layer, while layer of active root uptake of mineral matter for row crops shifts from the soil surface downward. Therefore, it can be recommended that the systematic monitoring of cultivated topsoil conditions based on preliminary assessment of Cs-137 vertical profile distribution, taking into account agrotechnical specifics of different crops within the crop rotation, must be carried out in order to obtain the reliable assessment of the soil radioecological status.

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“…Ciais et al, 2008;Doetterl et al, 2012). In the Fukushima region, radiocesium contamination is found in leaves, leaf litter and soil organic matter (Hashimoto et al, 2012;Koarashi et al, 2012;Loffredo et al, 2014). Therefore, the particulate matter was traced in both the bulk (<2 mm) and fine (<63 mm) fractions.…”

Section: Particulate Matter Propertiesmentioning

confidence: 99%

“…As the majority (~66%) of the landscape receiving high levels of radiocesium fallout (i.e. >1000 kBq m À2 ) were a mixture of evergreen and deciduous forests (Hashimoto et al, 2012), a significant quantity of radiocesium is also stored within the forest canopy, leaf litter, and soil organic matter (Hashimoto et al, 2013;Koarashi et al, 2012;Loffredo et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Do forests represent a long-term source of contaminated particulate matter in the Fukushima Prefecture?

Laceby

Huon

Onda

et al. 2016

Journal of Environmental Management

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a b s t r a c tThe Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in radiocesium fallout contaminating coastal catchments of the Fukushima Prefecture. As the decontamination effort progresses, the potential downstream migration of radiocesium contaminated particulate matter from forests, which cover over 65% of the most contaminated region, requires investigation. Carbon and nitrogen elemental concentrations and stable isotope ratios are thus used to model the relative contributions of forest, cultivated and subsoil sources to deposited particulate matter in three contaminated coastal catchments. Samples were taken from the main identified sources: cultivated (n ¼ 28), forest (n ¼ 46), and subsoils (n ¼ 25). Deposited particulate matter (n ¼ 82) was sampled during four fieldwork campaigns from November 2012 to November 2014. A distribution modelling approach quantified relative source contributions with multiple combinations of element parameters (carbon only, nitrogen only, and four parameters) for two particle size fractions (<63 mm and <2 mm). Although there was significant particle size enrichment for the particulate matter parameters, these differences only resulted in a 6% (SD 3%) mean difference in relative source contributions. Further, the three different modelling approaches only resulted in a 4% (SD 3%) difference between relative source contributions. For each particulate matter sample, six models (i.e. <63 mm and <2 mm from the three modelling approaches) were used to incorporate a broader definition of potential uncertainty into model results. Forest sources were modelled to contribute 17% (SD 10%) of particulate matter indicating they present a long term potential source of radiocesium contaminated material in fallout impacted catchments. Subsoils contributed 45% (SD 26%) of particulate matter and cultivated sources contributed 38% (SD 19%). The reservoir of radiocesium in forested landscapes in the Fukushima region represents a potential long-term source of particulate contaminated matter that will require diligent management for the foreseeable future.

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Factors affecting vertical distribution of Fukushima accident-derived radiocesium in soil under different land-use conditions

Cited by 179 publications

References 28 publications

Export of <sup>134</sup> Cs and <sup>137</sup> Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

Export of <sup>134</sup> Cs and <sup>137</sup> Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

Homo/Heterogeneity of Cs-137 Vertical Distribution Within Plough Horizons of Cultivated Chernozems – 30 Years After Chernobyl Accident

Do forests represent a long-term source of contaminated particulate matter in the Fukushima Prefecture?

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Factors affecting vertical distribution of Fukushima accident-derived radiocesium in soil under different land-use conditions

Cited by 179 publications

References 28 publications

Export of &lt;sup&gt;134&lt;/sup&gt; Cs and &lt;sup&gt;137&lt;/sup&gt; Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

Export of &lt;sup&gt;134&lt;/sup&gt; Cs and &lt;sup&gt;137&lt;/sup&gt; Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

Homo/Heterogeneity of Cs-137 Vertical Distribution Within Plough Horizons of Cultivated Chernozems – 30 Years After Chernobyl Accident

Do forests represent a long-term source of contaminated particulate matter in the Fukushima Prefecture?

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Export of <sup>134</sup> Cs and <sup>137</sup> Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011

Export of <sup>134</sup> Cs and <sup>137</sup> Cs in the Fukushima river systems at heavy rains by Typhoon Roke in September 2011