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Nguyen TP, Kurosawa T, Kikuchi M, Yoschenko V, Tsukada H. Estimation of rooting depth of 137Cs uptake by plants. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 246:106847. [PMID: 35219124 DOI: 10.1016/j.jenvrad.2022.106847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/08/2022] [Accepted: 02/17/2022] [Indexed: 06/14/2023]
Abstract
Understanding the soil-to-plant transfer process of 137Cs is essential for predicting the contamination levels of plants in contaminated areas. The rooting depth is considered one of the key factors explaining the difference in the activity concentration of 137Cs in different plant species. In this study, the distributions of 137Cs and 133Cs in soils and plants were investigated, and the plants' rooting depth of 137Cs uptake was estimated using the 137Cs/133Cs ratios in exchangeable fractions of soils and biological samples. The results showed that different plant species accumulate different levels of 137Cs and 133Cs. The 137Cs/133Cs ratios were fairly constant in plants of the same species. The average 137Cs/133Cs ratios in bamboo grasses and ferns were 0.015 ± 0.009 (n = 5) and 0.13 ± 0.04 Bq ng-1 (n = 10) in Yamakiya, respectively. The percentage of 137Cs in the exchangeable fraction of the uppermost soil layer was lower than that in the deeper soil layers. The activity concentrations of 137Cs in the soil profiles decreased sharply with depth, whereas the depth distributions of 133Cs were uniform. Therefore, the 137Cs/133Cs ratios were driven mainly by the 137Cs activity concentrations in soil. The plants' rooting depths of 137Cs uptake were estimated on the basis of the relationships between the averaged 137Cs/133Cs ratio in the soil layer and the 137Cs/133Cs ratio in the plant. The results indicate that the deeper-rooted species such as bamboo grasses have a lower accumulation of 137Cs than the superficial-rooting species such as ferns. The soil-to-plant transfer factors would be determined using rooting depth by calculating the averaged activity concentration of 137Cs within the estimated rooting depth.
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Affiliation(s)
- Thoa Phuong Nguyen
- Graduate School of Symbiotic Systems Science and Technology, Fukushima University, 1 Kanayagawa, Fukushima city, Fukushima prefecture, 960-1296, Japan; Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima city, Fukushima prefecture, 960-1296, Japan
| | - Takahide Kurosawa
- Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima city, Fukushima prefecture, 960-1296, Japan
| | - Mihoko Kikuchi
- Graduate School of Symbiotic Systems Science and Technology, Fukushima University, 1 Kanayagawa, Fukushima city, Fukushima prefecture, 960-1296, Japan; Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima city, Fukushima prefecture, 960-1296, Japan
| | - Vasyl Yoschenko
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima city, Fukushima prefecture, 960-1296, Japan
| | - Hirofumi Tsukada
- Institute of Environmental Radioactivity, Fukushima University, 1 Kanayagawa, Fukushima city, Fukushima prefecture, 960-1296, Japan.
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Lukšienė B, Marčiulionienė D, Gudelienė I, Schönhofer F. Accumulation and transfer of 137Cs and 90Sr in the plants of the forest ecosystem near the Ignalina Nuclear Power Plant. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2013; 116:1-9. [PMID: 23085187 DOI: 10.1016/j.jenvrad.2012.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Revised: 04/02/2012] [Accepted: 09/07/2012] [Indexed: 06/01/2023]
Abstract
The radioecological state of the forest ecosystem in the vicinity of the Ignalina Power Plant prior to decommissioning was analysed with specific emphasis on (137)Cs and (90)Sr activity concentrations in plant species growing in two reference sampling sites (Tilze and Grikiniskes). In the period of 1996-2008 the mean contamination of plants with (137)Cs was from 45 to 119 Bq/kg and with (90)Sr - from 3 to 42 Bq/kg. Measured (137)Cs TF values for soil-root transfer mainly ranged between 1.0-1.4, except for Calamagrostis arundinacea which had a TF value of 0.1. On average, the (137)Cs TF value from root to shoot was 1.7 fold higher than for soil to root transfer. (90)Sr TF values (soil-root) were in the range of 1.2-1.8 but for Calluna vulgaris it was 0.2. The mean root to shoot TF value for (90)Sr was 7.7 fold higher. These results indicate the higher (90)Sr bioavailability than that of (137)Cs in the forested area. The Grikiniskes reference site is located nearby the Ignalina NPP, specifically the heated water outlet channel, which results in altered microclimatic conditions. These specific microclimatic conditions result in relationships between (137)Cs TF (soil-root) values and pH, moisture and organic matter content in the soil at Grikiniskes which appear to be different to those at the Tilze reference sampling site.
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Affiliation(s)
- B Lukšienė
- Center for Physical Sciences and Technology, Savanorių Ave. 231, LT-02300 Vilnius, Lithuania.
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