Accumulation of by fungal mycelium in forest ecosystems of Ukraine

Cesium (137Cs and 133Cs), Potassium and Rubidium in Macromycete Fungi and Sphagnum Plants

“…However, 133 Cs concentrations in sporocarps were nearly one order of magnitude higher than those found in soil mycelium. Radioactive 137 Cs presented similar to 133 Cs behavior, where 137 Cs activity increased in the order soil<mycelium<fungal sporocarps (Vinichuk & Johanson, 2003;Vinichuk et al, 2004). The differences between fungal species in their preferences for uptake of 137 Cs or stable 133 Cs appear to reflect the location of the fungal mycelium relative to that of cesium within the soil profile (Rühm et al, 1997 Cs (Yoshida & Muramatsu, 1998).…”

“…The prepared fraction of mycelium (30−60 mg DW g -1 soil) was not identified to determine of the mycelia extracted from the soil samples and the sporocarps belonged to the same species, as it assumed a majority of the prepared mycelia belonged to the same species as the nearby sporocarps. The method for mycelium preparation is described in Vinichuk & Johanson (2003). Mycelium samples were dried at 35°C to constant weight for determination of K, Rb and 133 Cs.…”

“…137 Cs transfer in the forest The availability of radionuclides ( 137 Cs in particular) in soils of different ecosystems is to a large extent regulated by various vascular plants and fungal species. Thus, the behavior of 137 Cs in forest ecosystems differs substantially from other ecosystems, foremost due to the abundance of fungal mycelia in soil, which contribute to the persistence of the Chernobyl radiocesium in the upper horizons of forest soils (Vinichuk & Johanson, 2003). Both saprotrophic and mycorrhizal fungi have key roles in nutrient and carbon cycling processes in forest soils.…”

“…Fungal mycelium may act as a sink for radiocesium (Dighton et al, 1991;Olsen et al, 1990), as it contains 20-30% 137 Cs in soil inventories, and as much as 40% of radiocesium can leached from irradiated samples compared to control samples (Guillitte et al, 1994). Mycelium in upper organic soil layers may contain up to 50% of the total 137 Cs located within the upper 0-10 cm layers of Swedish and Ukrainian forest soils (Vinichuk & Johanson 2003). In terms of the total radiocesium within a forest ecosystem, fungal sporocarps contain a small part of activity and may only account for about 0.5 % (McGee et al, 2000) or even less − 0.01 to 0.1% (Nikolova et al, 1997) of the total radiocesium deposited within a forest ecosystem.…”

“…However, these estimates are based on the assumption radionuclide concentration in fungal sporocarps is similar to that of the fungal parts of mycorrhizae (Nikolova et al, 1997). The activity concentration in sporocarps is probably higher than in the mycelium (Vinichuk & Johanson, 2003 and sporocarps constitute only about 1% of the total mycelia biomass in a forest ecosystem. Due to the high levels of 137 Cs in sporocarps, their contribution to the internal dose in man may be high through consumption of edible mushrooms (Kalač, 2001).…”