Gerzabek


Die Bodenkultur - Journal for Land Management, Food and Environment

M. H. Gerzabek, K. Mück, F. Steger and S. M. Algader:

Leaching of 6OCO, 137CS and 226Ra in lysimeter experiments

Summary

The present report describes the first results obtained from lysimeter experiments started in 1990. The lysimeter plant consists of twelf soil monoliths from four different sites (three replicates each). Since 1990 the following agricultural crops were grown: endive, corn, winterwheat, mustard, sugar beet and potato.

Gravitational water ranged from 3.9 % to 18.3 % of precipitation plus irrigation water, calculated as half years average values excluding the first six month of operation. The two Cambisols on sediments exhibited a mean percentage of app. 10 %. The Dystric Cambisol on silicate rock and the Gleysol showed average values of 20 %.

In 1990 the top layers (20 cm) were contaminated with three radionuclides. The Ieaching of the contaminants 60Co, 137Cs and 226Ra differed distinctly between the elements. The lowest leaching rates were observed for 137Cs, followed by 60Co. The 226Ra-concentrations in the gravitational water were clearly highest of all. However, the comparison of the 226Ra/228Ra ratios in deep soil layers and in gravitational water showed that the 226Ra measured in the leachate originates from the natural contents in the subsoil and not from the artificial 226Ra contamination of the topsoil. The mobility of the artificial radionuclides decreased therefore in the following order: 60Co > (226Ra) > 137CS.

Key words: Austrian soils, leaching, lysimeter, radionuclides.