Radionuclide Transfer in Alpine Regions

Seibersdorf

1998

82 S.

Lit. Ang.

Bandaufführung

104710

The present paper discusses differences observed between agricultural and alpine ecosystems with respect to radiocaesium transfer taking Austrian pastures as an example. During the first years after the Chernobyl fallout it was observed that 137Cs-concentrations in milk decreased more or less independently from the total amount of fallout in May 1986. Calculating aggregated transfer factors (soil-to-milk) three categories of radiocaesium availability could be distinguished. Two of them could be linked to soil characteristics, the third category showing 10 to 100 times higher values comprised alpine sites. The alpine areas are characterized by (i) slower migration velocities of radiocaesium in soil and (ii) an on average 30 times higher soil-to-forage transfer factor than agricultural ecosystems. In a case study on an alpine pasture in Salzburg/Austria it could be shown that the living and dead plant biomass contributes significantly to the overall sink capacity of the respective ecosystem. In 1990 between 12.6 and 24.6% of the total 137Cs-inventory was found in roots + shoots + litter. At lowland sites this value normally does not exceed few percents. It was concluded that besides extreme soil properties, climatic factors like a short vegetation period and a long snow cover and the fixation and cycling of radiocaesium in alpine biomass should be considered as main factors influencing the decrease of Cs-transfer to forage and milk in alpine regions.