Accumulation of potassium, rubidium and caesium (Cs and Cs) in various fractions of soil and fungi in a Swedish forest

Department of Soil and Environment, Swedish University of Agricultural Sciences, P.O. Box 7014, SE-750 07, Uppsala, Sweden.
Science of The Total Environment (Impact Factor: 4.1). 03/2010; 408(12):2543-8. DOI: 10.1016/j.scitotenv.2010.02.024
Source: PubMed


Radiocaesium ((137)Cs) was widely deposited over large areas of forest in Sweden as a result of the Chernobyl accident in 1986 and many people in Sweden eat wild fungi and game obtained from these contaminated forests. In terms of radioisotope accumulation in the food chain, it is well known that fungal sporocarps efficiently accumulate radiocaesium ((137)Cs), as well as the alkali metals potassium (K), rubidium (Rb) and caesium (Cs). The fungi then enhance uptake of these elements into host plants. This study compared the accumulation of these three alkali metals in bulk soil, rhizosphere, soil-root interface, fungal mycelium and sporocarps of mycorrhizal fungi in a Swedish forest. The soil-root interface was found to be distinctly enriched in K and Rb compared with the bulk soil. Potassium concentrations increased in the order: bulk soil<rhizosphere<fungal mycelium<soil-root interface<fungal sporocarps; and Rb concentration in the order: bulk soil<rhizosphere<soil-root interface<fungal mycelium<fungal sporocarps. Caesium was more or less evenly distributed within the bulk soil, rhizosphere and soil-root interface fractions, but was actively accumulated by fungi. Fungi showed a greater preference for Rb and K than Cs, so the uptake of (137)Cs could be prevented by providing additional Rb or K at contaminated sites. The levels of K, Rb, and Cs found in sporocarps were at least one order of magnitude higher than those in fungal mycelium. These results provide new insights into the use of transfer factors or concentration ratios. The final step, the transfer of alkali metals from fungal mycelium to sporocarps, raised some specific questions about possible mechanisms.

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Available from: Klas Rosén, Jan 15, 2014
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    • "Large areas of forest in Sweden were analyzed for the deposition of radiocesium ( 137 Cs) after the Chernobyl accident in 1986, and they showed largescale accumulation. Twenty woody plants (12 evergreen and 8 deciduous species) grown in Abiko indicated radiocesium deposition after the Fukushima Power Plant accident, and they showed an average radiocesium activity 7.7 times higher than the activity in the leaves of deciduous species (Vinichuk et al. 2010; Okumura et al. 2014). The other factors that show a potential to release radiological contaminants to the environment include radionuclide activity concentrations in litter (i.e., vegetative debris) and duff (i.e., highly decomposed vegetative debris). "
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    ABSTRACT: Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is (137)Cs, which is released as a result of weapon production related to atomic projects, accidental explosions of nuclear power plants and other sources, such as reactors, evaporation ponds, liquid storage tanks, and burial grounds. The release of potentially hazardous radionuclides (radiocesium) in recent years has provided the opportunity to conduct multidisciplinary studies on their fate and transport. Radiocesium's high fission yield and ease of detection made it a prime candidate for early radio-ecological investigations. The facility setting provides a diverse background for the improved understanding of various factors that contribute toward the fate and transfer of radionuclides in the terrestrial ecosystem. In this review, we summarize the significant environmental radiocesium transfer factors to determine the damaging effects of radiocesium on terrestrial ecosystem. It has been found that (137)Cs can trace the transport of other radionuclides that have a high affinity for binding to soil particles (silts and clays). Possible remedial methods are also discussed for contaminated terrestrial systems. This review will serve as a guideline for future studies of the fate and transport of (137)Cs in terrestrial environments in the wake of the Fukushima Nuclear Power Plant disaster in 2011.
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    • "These findings are generally in accordance with previous findings [5]. In the current study, K levels were between 3 and 18 times higher in FBs in the substrates; this is lower than previously reported ratios (20~105) [14, 16], and was consistent with the result showing that the K content ratio between fungi and substrate was different among species [16]. "
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    • "In the field layer, heather was the predominant dwarf shrub intermixed with bilberry (Vaccinium myrtillus L.) and lingon berry (Vaccinium vitis-idaea L.). The study site is displayed in Fig. 1: a detailed description of the site is provided by Vinichuk et al. (2010a). In 2005, the ground deposition of 137 Cs on peatland was about 23 kBq m À2 (Rosén et al., 2009). "
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