Increased levels of cesium-137 and cesium-134 in 34 mushroom species following the reactor accident at Chernobyl

From September to December of 1986, 85 samples of 34 species of wild mushrooms were collected, mostly in northern Baden and occasionally in neighboring areas. Cs-137, Cs-134, and the natural nuclide K-40 were determined by gamma-spectrometry. Samples from the Rhine Valley and the Kraichgau were generally much less contaminated than those from the Black Forest. With one exception, their radiocesium levels were below the Common Market limit of 600 Bq/kg. The exception was a sample of Laccaria amethystina with 1710 Bq/kg Cs-137 and 766 Bq/kg Cs-134. Relatively high levels were also found in Xerocomus badius, X. chrysenteron and Cantharellus tubaeformis. The hymenophore contained higher concentrations of radiocesium than the other parts of the body of the fruit. No correlation between the concentration of K-40 and that of the Cs nuclides was found. The ratio of Cs-137:Cs-134 was usually below 3 but reached the value of 11.8 in Piptoporus betulinus growing on birch wood. In this case, the substrate must have contained more radiocesium from the time before the Chernobyl reactor accident than from the time thereafter.