Extensive analysis of radiocesium concentrations in wild mushrooms in eastern Japan affected by the Fukushima nuclear accident: Use of open accessible monitoring data.

After the Fukushima Daiichi Nuclear Power Plant accident, there has been an increasing concern regarding the contamination of wild mushrooms with radiocesium (¹³⁴Cs and ¹³⁷Cs) in eastern Japan. In this study, we analyzed the radioactivity monitoring data of 3189 wild edible mushrooms of 107 species collected by the 265 local municipalities in eastern Japan to investigate the radiocesium levels in wild mushrooms. Results of the analysis showed that radiocesium concentrations in mushrooms were normalized with radioactivity deposition data from aircraft monitoring, and then we evaluated the effects of species, sampled location, sampling year and regional deviation between ¹³⁴Cs and ¹³⁷Cs activity of specimens using a hierarchical Bayesian approach considering spatial autocorrelation (an intrinsic CAR model). Normalized activity concentration by species ranged from 1.1 × 10 − 4 to 2.3 × 10 − 2 (m² kg⁻¹, fresh weight). As reported in previous studies, the mycorrhizal species tended to have higher radiocesium concentrations. Some saprophytic species (e.g. Pholiota lubrica) also had high concentrations. For the mushroom species that were also evaluated in the post-Chernobyl studies, we found that the same species had similar trends of absorption capacities. Our results indicate the extensive analysis of public monitoring data is helpful to understand the situation of mushroom contamination and evaluate the internal dose by ingestion of wild mushrooms according to species and areas. Image 1 • Radioactivity data of 3189 wild edible mushrooms of 107 species were analyzed. • A hierarchical Bayesian analysis considering spatial autocorrelation worked well. • Mycorrhizal and some saprophytic species tended to have higher radioactivity. • Species-wise radioactivities were positively correlated with those in Chernobyl. We provided reliable species characteristics of radiocesium in wild mushrooms which could be utilized for current and future contamination issues. [ABSTRACT FROM AUTHOR]