Radiocaesium and natural gamma emitters in mushrooms collected in Spain

Mushrooms can accumulate heavy metals in general, including radionuclides found in the nature. However, little attention has been paid to the radioactive content of mushrooms collected in Spain and the dose for the population due to their ingestion. To address this, we analysed the contents of Cs-137, K-40, Ra-226 and Be-7 present in different species of mushrooms, according to their genus and nutritional mechanism. We observed that mycorrhizal mushrooms accumulate Cs-137 more than saprophytes, and vice versa for Be-7. K-40 and Ra-226 are accumulated to the same degree by the two groups of mushrooms. We estimated the dose due to ingestion of mushrooms in Spain to be 2 muSv/year, and the contribution of K-40 and Ra-226 to be generally greater than that of Cs-137. The contribution of Cs-137 to the dose was calculated by taking into account the results of an experiment carried out under the controlled laboratory conditions, which showed that approximately 98% of Cs-134 was associated with the readily digestible fraction of the mushrooms. (C) 2003 Elsevier Science B.V. All rights reserved.