Natural and artificial radionuclides in selected Styrian soils and plants before and after the reactor accident in Chernobyl

This paper reports on natural radioactivity due to the uptake of 40K and the radionuclides of the 238U and 232Th series. Selected examples show the concentrations of radionuclides in soils, lower and higher plants before and after the Chernobyl accident. The changes in the amount of radioactivity which have occurred during the vegetation periods of 1987 and 1988 have been investigated. It is also demonstrated how the conditions have changed in the following two periods of growth. In leaves of deciduous trees which were directly contaminated in 1986 natural radioactivity is sometimes higher than artificial one today. This has not been observed in conifers, because the needles contaminated in 1986 have not yet been shed. The 137Cs activity in mosses and lichens has hardly decreased. It is therefore possible to produce autoradiographs at the Styrian test site locations. Within the same genus of fungi, Cs-discriminating and Cs-accumulating species have been noted. In the latter, radioactivity has probably increased since 1986. (author)