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We developed a simple and rapid method for detecting dissolved radio-Cs in litter and/or soil seepage water using nonwoven fabrics impregnated with copper-substituted Prussian blue (Cu-NF). In laboratory and field experiments, litter and/or soil seepage water including dissolved radio-Cs were passed through traditional lysimeter systems combined with seven sheets of the Cu-NF. We then examined the recovery ratios of dissolved 137 Cs in the Cu-NF. In the laboratory experiments with faster flow rates (11–2200 mm h −1 ), over 86% of the total dissolved 137 Cs in litter seepage water was detected in the Cu-NF and over 82% of the collected 137 Cs was present in the first three sheets. In the field experiments, 99% of the total dissolved 137 Cs litter seepage water was collected in the Cu-NF and more than 96% of the collected 137 Cs was present in the first three sheets. Furthermore, the recovery ratio of dissolved 137 Cs increased with increasing installation Cu-NF length, probably because the packed soil in the Cu-NF lysimeter become more stable over time. Finally, because only the Cu-NF is measured, it is not necessary to undertake traditional measurement preparations such as filtration to remove particulate radio-Cs materials and evaporative concentration for low concentration of radio-Cs. As a result, we can save time and effort in measurement preparation by using the Cu-NF lysimeter method. [ABSTRACT FROM AUTHOR]

Ingestion of edible wild mushrooms collected in areas contaminated with radiocesium released from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident may pose a risk of internal dose to their consumers. A species-specific aggregated transfer factor (T ag), which is calculated using radiocesium concentration in a wild mushroom species (Bq kg−1 wet mass [WM]) divided by the total concentration in the soil surface area (Bq m−2), would be a useful tool to estimate the dose from wild mushrooms by ingestion. In this study, we especially focused on the T ag data collected in 2016–2020 to use these values for a long-term dose assessment. We assumed that 137Cs concentrations after that year were almost the same, thus the soil-mushroom system would be in an apparent steady-state condition. In all, we could obtain T ag values of 137Cs in 62 edible wild mushroom species native to Japan. The geometric mean (GM) values were 1.5 × 10−3 m2 kg−1 WM using GMs of 13 saprobic type species and 5.0 × 10−3 m2 kg−1 WM using GMs of 21 mycorrhizal type species (N > 2). On average, the GMs of species-specific T ag values were 1.9 ± 0.9 times higher than those reported in a previous study of wild mushrooms made after the FDNPP accident, probably due to the different approaches for T ag calculation. • Aggregated transfer factor (T ag) of 137Cs from soil to wild mushroom was calculated. • Open source in-situ soil measurement data of 137Cs were used for T ag calculation. • T ag values obtained before and after the Fukushima accident did not change much. • 137Cs could be estimated for each mushroom species by using T ag values. [ABSTRACT FROM AUTHOR]