Deposition av 7Be och 137 Cs i Sverige 2001 - 2008
Publish date: 2009-11-02
Report number: FOI-R--2835--SE
Pages: 23
Written in: Swedish
Keywords:
- airborne radionuclides
- deposition
- 7Be
- 137Cs
- resuspension
Abstract
Deposition of 7Be and 137Cs for four stations in Sweden are reported for the period 2001- 2008. For 7Be a correlation with total precipitation is seen. For 137Cs there is no correlation with precipitation and no correlation with surface air concentrations of 137Cs. The overall levels of 137Cs fallout is higher in areas that were largely affected by the Chernobyl fallout in 1986. The 137Cs deposition seen in the Gävle area are mostly due to resuspension of this 137Cs fallout, but for other areas the total yearly deposition and resuspension are down to pre Chernobyl levels. Filtering of ground level air is performed continuously at six different locations in Sweden: Kiruna, Umeå, Gävle, Kista, Visby and Ljungbyhed. The filters are pressed into weekly samples and the contents of different radionuclides are measured by gamma spectroscopy. Precipitation is also collected at four of the stations: Kiruna, Gävle, Kista and Ljungbyhed, the samples are ashed and the contents of radionuclides are measured. The levels of Be-7 and Cs-137 during 2008 in air and precipitation are presented for the different stations. Other antropogenic radionuclides detected, if any, are also presented.