137 Cs in mushrooms from Croatia sampled 15–30 years after Chernobyl

Abstract The aim of this study was to select species with higher potential to accumulate 137 Cs among the available mushroom species, by determining the activity concentrations of 137 Cs in mushrooms collected along north and north-western part of Croatia. A total of 55 samples of 14 different species were analyzed and the potential of mycorrhizal and saprotrophic species to accumulate 137 Cs was compared. A wide range of the dry weight activity concentrations of 137 Cs was detected, ranging from 0.95 to 1210 Bq/kg (154 Bq/kg mean value; 52.3 Bq/kg geometric mean) in mycorrhizal and 1.05–36.8 Bq/kg (8.90 Bq/kg mean value; 5.49 Bq/kg geometric mean) in saprotrophic species. Statistical analyses showed that mycorrhizal species accumulate significantly higher concentrations of 137 Cs and thus could perform better as long-term bioindicators of environmental pollution by radiocaesium then saprotrophic species. The comparison of Boletus sp. and Hydnum repandum (both mycorrhizal species commonly found in Croatia) showed, in general order of magnitude, higher accumulation in Hydnum repandum. Clearly, mushrooms, especially mycorrhizal species, can be used as significant indicators even decades after the occurrence of any serious 137 Cs contamination event. However, as a wide range of values indicates that various parameters may influence the total uptake of the 137 Cs into the mushroom fruit bodies, it is necessary to emphasize that 137 Cs activity detected in a single mushroom sample is very site-specific.