Health Psychology
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Long-term studies on transfer of Cs from soil to vegetation and to grazing lambs in a mountain area in Northern Sweden Inger Andersson *, Hans LoK nsjoK , Klas RoseH n Department of Agricultural Biosystems and Technology, Swedish University of Agricultural Sciences, S-230 53 Alnarp, Sweden Department of Radioecology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden Department of Soil Sciences, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden Received 15 November 1998; received in revised form 20 March 2000; accepted 30 March 2000
Abstract Studies were made during 1990}1997 on the transfer of Cs from soil to vegetation (herbage) and to grazing lambs on a mountain farm with an uncultivated grazing area of about 10 km. The farm is situated in an area in Northern Sweden which was contaminated by the Chernobyl fallout in 1986. The mean concentration of Cs in the soil to a depth of 10 cm for eight sampling sites observed in the 8-year period was 14.51 kBq/m, while in the cut herbage the average concentration was 859 Bq/kg d.w. and in lamb meat 682 Bq/kg w.w. A slow vertical migration of Cs in the 0}10 cm soil layer was indicated. Although the Cs concentration in herbage gradually decreased, the concentration in lamb meat varied from year to year. Soil ingestion by the lambs as a pathway for activity transfer was shown to be negligible, while ingestion of fungi with high concentrations of Cs was demonstrated to occur, as large numbers of fungi spores were counted in samples of the lambs' faeces. Fungi ingestion might therefore partly explain the varying mean yearly Cs concentrations in lamb muscle. The mean transfer parameters were as follows: for `soil to herbagea 61.3 Bq/kg d.w. herbage per kBq/m soil, for `herbage to lamb meata 0.81 Bq/kg w.w. meat per Bq/kg d.w. herbage, and for `soil to lamb meata 47.1 Bq/kg w.w. meat per kBq/m soil. A trend of decreasing values of the transfer parameter for `soil to herbagea indicated that Cs was becoming less available for root-uptake with time. The e!ective ecological half-life of Cs in soil, herbage and lamb meat was calculated to be 19, 7 and 16 years, respectively. It can be concluded that natural areas are vulnerable to Cs contamination, resulting in high concentrations in plants, fungi and lamb meat for a long time. 2000 Elsevier Science Ltd. All rights reserved. Keywords: Cs; Ecological half-life; Soil; Uncultivated pasture; Lambs; Fungi intake * Corresponding author. 0265-931X/00/$ - see front matter 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 5 - 9 3 1 X ( 0 0 ) 0 0 1 0 2 - 8
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I. Andersson et al. / J. Environ. Radioactivity 52 (2001) 45}66
1. Introduction Natural or semi-natural areas have proved to be susceptible to radiocaesium fallout. The soils of these areas are often poor in nutrients and soil characteristics are such that a high uptake of radiocaesium by the plants is facilitated. The radioactivity transfer to grazing animals and accumulation in animal pro
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