Assessment of the role of soil adhesion in the transfer of 137Cs and 40K to pasture grass

Gastrointestinal fractional absorption of radionuclides in adult domestic ruminants

“…In one study, the same contaminated soil was administered to both cattle and sheep (Mayes et al, 1993;Beresford et al, 2000a) but the A t value determined for cattle (0.2) was an order of magnitude higher than that determined in sheep. Although soil adhered to ingested vegetation often forms an important component of the total radiocaesium intake (Beresford and Howard, 1991;Rafferty et al, 1994) it is generally not an important contribution to radiocaesium in animal-derived products (Crout et al, 1993) because of the lower availability of Cs associated with ingested soil compared to that of Cs in vegetation. However, it can be an important source in some circumstances, for example, animals grazing tidally inundated pastures near the Sellafield reprocessing plant, can ingest over 90% of their radiocaesium intake in the form of contaminated silt particles deposited by the tide on vegetation surfaces , and roughly 60% of radiocaesium in sheep tissues has been estimated to be derived from the silt even though the A t for Cs ingested in this form is only of the order of 0.1 Singleton et al, 1992).…”

Genotypic differences in the uptake and distribution of radiocaesium in plants

“…A different transfer factor can result from differences in rooting pattern, rooting depth, degree of mycorrhization, exudation rates, absorption characteristics of the root surface, ion competition effects in the rhizosphere, root turnover, root growth rate and adhesion of soil particles to leaves (Bell et al, 1988;Rafferty et al, 1994;Riesen and Brunner, 1994;Shaw, 1993;. A different transfer factor can result from differences in rooting pattern, rooting depth, degree of mycorrhization, exudation rates, absorption characteristics of the root surface, ion competition effects in the rhizosphere, root turnover, root growth rate and adhesion of soil particles to leaves (Bell et al, 1988;Rafferty et al, 1994;Riesen and Brunner, 1994;Shaw, 1993;.…”

Will global warming affect soil-to-plant transfer of radionuclides?

“…Highest transfer of 137 Cs was observed in the winter months whereas the highest transfer of 40 K was during spring-summer. Seasonal variability in the transfer of soil particles to vegetation surfaces (high transfer in winter due to short grass, high rainfall and high grazing intensity) was concluded to be the most likely explanation and was confirmed by further study (Rafferty et al, 1994b). Kirchner and Ehlken (1997) noted some weak general trends with temperature and precipitation and concluded that the interplay of variables with soil hydrological properties caused seasonal variations in uptake.…”