Vertical distribution of 137Cs in the contaminated soil of a spruce forest in Southern Germany 12Â years after regeneration cutting

The Chernobyl fallout of 1986 contaminated soils in Southern Germany. Levels of 137Cs activity still remain high in forest soils. The contamination of forest food products still poses a serious problem for consumer health. Silvicultural interventions may offer an option to reduce the bioavailability of 137Cs. The objective of this study is to investigate a possible effect of canopy opening and clearcutting as well as the selection of conifers and broadleaves for stand regeneration on the vertical soil profile of 137Cs. The investigation uses a long-term silvicultural experiment on the artificial regeneration of a spruce stand 30 km southwest of the town Augsburg, Germany. 12 years after silvicultural intervention soil samples were taken horizon-wise and analysed to compare among the treatments. A suite of soil physical and chemical properties was determined per horizon including 137Cs radioactivity, total carbon, texture, and cation exchange capacity. The results show that (i) the 137Cs contamination at this site is high compared to other sites in Central Europe, (ii) regeneration cuttings did not markedly change the vertical 137Cs profile in general within one decade, (iii) clear cutting modified the boundary between the organic soil layer and the mineral soil with expectable effects on the future 137Cs bioavailability.