Fallout Cs-137 and natural K-40 in fungal fruitbodies in Ireland

Fruitbodies of 26 genera of fungi were collected from seven forest sites in Ireland and analysed for Cs-137 and K-40. High variability in the concentr ation of radionuclide activity was observed both between and within the dif ferent genera sampled. Uptake of Cs-137 over the entire sample set, was sig nificantly related to soil Cs-137 but no such relationship was found for K- 40 demonstrating a differentiation between these analogous elements at some stage during uptake. At the level of individual genera only two genera, Ru ssula and Laccaria, showed a significant relationship between Cs-137 activi ty concentration in the fruitbody and deposition to soil. No such relations hip was identified for K-40. Some fungal samples, especially from the genus Cortinarius had accumulated high levels of Cs-137 - UP to 55 kBq/kg dry ma tter. A worst-case scenario calculation of radiation dose received by man f rom heavy consumption of mild fungi showed that the dose contribution was e quivalent to 11 to 16% of the average annual dose received by a typical adu lt member of the Irish population. A more realistic scenario calculation es timated a dose contribution of 4%.