Transfer across the human gut of environmental plutonium, americium, cobalt, caesium and technetium: studies with cockles ( Cerastoderma edule) from the Irish Sea
Hunt, G J; Hunt, G J; CEFAS Laboratory, Lowestoft, Suffolk NR33 0HT, UK
Журнал:
Journal of Radiological Protection
Дата:
1998-06-01
Аннотация:
Our previous studies have indicated lower values of the gut transfer factor (`f<sub>L</sub> values') for plutonium and americium in winkles ( Littorina littorea) than adopted by ICRP. The present study was undertaken primarily to investigate whether this observation extends to other species. Samples of cockles ( Cerastoderma edule) from Ravenglass, Cumbria were eaten by volunteers who provided 24 samples of urine and faeces. Urine samples indicated f<sub>L</sub> values for cockles which were higher than for winkles; for plutonium these ranged overall up to 7 × 10<sup>-4</sup> with an arithmetic mean in the range (2 - 3) × 10<sup>-4</sup>, and for americium up to 2.6 × 10<sup>-4</sup> with an arithmetic mean of 1.2 × 10<sup>-4</sup>. Limited data based on volunteers eating cockles from the Solway suggest that f<sub>L</sub> values for americium may be greater at distance from Sellafield. The measured values compare with 5 × 10<sup>-4</sup> used by the ICRP for environmental forms of both elements, which would appear to provide adequate protection when calculating doses from Cumbrian cockles. Data for other nuclides were obtained by analysing faecal samples from the volunteers who ate the Ravenglass cockles. Cobalt-60 showed an f<sub>L</sub> value in the region of 0.2, twice the value currently used by ICRP. For <sup>137</sup>Cs, variabilities were indicated in the range 0.08 to 0.43, within the ICRP value of f<sub>L</sub> = 1.0. Technetium-99 gave f<sub>L</sub> values up to about 0.6, in reasonable conformity with the ICRP value of 0.5.
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