Abstract
After the Chernobyl accident, high concentrations of radiocesium in mushrooms were found in Europe. In our previous studies, we found that 137Cs concentrations in mushrooms were markedly higher than autotrophic plants. In order to study radionuclide uptake by mushrooms, cultivation experiments in flasks were carried out using radiotracers, 137Cs, 85Sr, 60Co, 54Mn and 65Zn. Three mushroom species Hebeloma vinosophyllum, Flammulina velutipes and Coprinus phlyctidosporus were used. In addition, a plant sample, Medicago sativa, was also tested. We found mushrooms tended to accumulate Cs, although there was a large difference between mushroom species. The concentration ratio, which was defined as“activity of radionuclide in mushroom (Bq/g, wet wt.) ”divided by“activity of radionuclide in medium (Bq/g, wet wt.) ”, had the highest value of 21 for Cs in H. vinosophyllum. The value was much higher than that in the plant sample. The present findings agreed with our previous observations in which Hebeloma species collected in forests contained large amount of 137Cs. Considerable accumulations were not found for Sr and Co. The concentration ratio of Mn for the mushrooms was about 10, while the ratio of Zn ranged from 15 to 30. The effects of stable elements in the medium on the accumulations were investigated and was found that the concentration ratios of Cs, Sr and Co were not influenced highly by coexisting stable elements in the medium. But the concentration ratio of Mn decreased as the amount of coexisting stable elements in the medium was increased.
