Explaining the variation in 137Cs aggregated transfer factor for wild edible plants as a case study on Koshiabura (Eleutherococcus sciadophylloides) buds

• Published in: Scientific reports 2023-08, Vol.13 (1), p.14162-14162, Article 14162
• Main Authors: Hayashi, Seiji, Watanabe, Mirai, Kanao Koshikawa, Masami, Takada, Momo, Takechi, Seiichi, Takagi, Mai, Sakai, Masaru, Tamaoki, Masanori
• Format: Article
• Language: English
• Subjects: 631/449; 704/172; 704/47; Buds; Case studies; Cesium radioisotopes; Deciduous forests; Eleutherococcus; Environmental studies; Forest products; Humanities and Social Sciences; Inventories; multidisciplinary; Nuclear accidents & safety; Nuclear power plants; Organic soils; Science; Science (multidisciplinary); Soil horizons; Soils; Transfer factor; Variation
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-023-41351-7

The aggregated transfer factor (T ag ) 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 137 Cs distribution in the soil on the variation of T ag - 137 Cs values for one of the most severely contaminated wild edible plants, Eleutherococcus sciadophylloides Franch. et Sav. (Koshiabura). The variation in T ag - 137 Cs values was not reduced by direct measurement of 137 Cs deposition in soil samples from the Koshiabura habitat, as a substitute for using spatially averaged airborne survey data at the administrative district scale. The 137 Cs activity concentration in Koshiabura buds showed a significant positive correlation with the 137 Cs inventories only in the organic horizon of soil from the Koshiabura habitat. The ratio of 137 Cs inventories in the organic horizon to the total 137 Cs 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 T ag - 137 Cs values observed in Koshiabura buds when calculated from the total 137 Cs deposition in soil.