Results of the investigation: Examination of ecosystems after the Tschernobyl incident in respect to radiation contamination of the population.
Like in plants the various mushroom species differ greatly in their uptake of Cs-137. Figure 1 shows the Cs-137 activity of different mushroom species growing on sample plot B1 from the
investigation area Bodenmais.
Fig. 1: Cs-137 activity in mushrooms , sample plot B1 and environment, autumn 2000
Columns = average values, upper and lower whisker = minimum and maximum values
On average Xerocomus subtomentosus with 300 Bq/kg and Armillaria mellea with 400 Bq/kg
both as fresh mushrooms were the least contaminated edible mushrooms. Cantharellus cibarius , Boletus edulis, and Xerocomus chrysenteron showed an average activity of 1000
Bq/kg, average contamination range. Amanita spissa and Xerocomus badius with 1,700 and 3,030 Bq/kg respectively had on average distinctly higher contents of Cs-137. Much more
highly contaminated was Cortinarius hercynicus with 6,750 Bq/kg. The Cs-137 content of the subterranean Elaphomyces granulatus
with an average of 25,660 Bq/kg exceeded the activities of the above ground muhrooms by far.
Figure 2 presents the data for the mushrooms taken from F1 in Fuhrberg. Just as in
Bodenmais the individual species vary greatly in their average Cs-137 contents. The intraspecific variation was also very high. The Cs-137 results obtained for 4 samples of
Laccaria amethysta based on fresh substance ranged from 57 Bq/kg to 430 Bq/kg with an average value of 170 Bq/kg. For 12 samples of Xerocomus badius Cs-137 values between
154 and 1,020 Bq/ kg were determined.
Fig. 2 Cs-137 activity in mushrooms on sample plot F1 and environment, autumn 2000
Columns = average values, lower and upper whiskers = minimum and maximum values
The sequence of Cs-137 activities in the various mushroom species on F1 was similar to that
on sample plot B1. The lowest activity was shown by Macrolepiota procera with 5 Bq/kg. Cantharellus cibarius also contained relatively low amounts of Cs-137, 97 Bq/kg. Since only
one specimen of each of these two species could be analyzed, the data are not presented in Fig.2. Thus the lowest Cs-137 contents were in Russula paludosa wih an average of 89Bq/kg.
Clearly higher values were shown by Scleroderma aurantium with 309 Bq/kg, Boletus badius 354 Bq/kg, and Xerocomus chrysenteron 359 Bq/kg. Data from previous years for the
mushrooms were insufficient to investigate trends in the temporal course of Cs-137 activity.
On sample plot G1 in Göttingen the spectrum of mushroom species differed from that on B1
and F1 due to different soil conditions, esp a high pH-value. For several species the activity values based on dry matter were less than the lowest measurable value of 0.5 Bq/kg. These
species included Lycoperdon pyriforme, Agaricus silvicola, and Amanita spissa. Fresh specimens of Boletus sp also showed relatively low Cs-137 activity : Boletus badius had an
average value of 8.8 Bq/kg (n =6). Xerocomus chrysenteron 6.4 Bq/kg (n = 1). Higher activites were shown by a sample of Russula heterophylla 28.4 Bq/kg and Russula farinipes 178 Bq/kg.
Based on the sample plots of all 3 investigation areas the lowest Cs-137 activity (<0.5 Bq/kg) in fresh specimens for the year 2000 was found in the species: Lycoperdon pyriforme, Agaricus
silvicola, and Amanita spissa on sample plot G1, the highest activity with 34,870 Bq/kg in Elaphomyces granulatus on sample plot B1.
These values respectively represent the minimum and maximum values for Cs-137 activity in mushrooms in the Federal Republic of Germany
in the year 2000, the activity ranges across a span of 5 orders of magnitude. Fig 3 clearly depicts this great range of Cs-137 content for the edible mushroom Boletus badius.
Fig. 3: Cs-137 activity in Boletus badius in the investigation areas, 2000 Logarithmic presentation.
This research was conducted with funds of the Federal Ministery for Environment. Nature Protection, and Reactor Safety.
This report reflects the views and opinions of the contractor and need not necessarily correspond to those of the sponsor.
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