Beresford N A, Barnett C L, Mayes R W
Centre for Ecology and Hydrology, Grange-over-Sands, Cumbria, UK.
Radiat Environ Biophys. 2000 Sep;39(3):207-12. doi: 10.1007/s004110000064.
A study is described in which 137Cs intake by free-ranging sheep was estimated at two farms in the area of west Cumbria (northwest England) which received some of the highest amounts of fallout from the Chernobyl accident within the United Kingdom. The faecal excretion of 137Cs was estimated from faecal 137Cs activity concentrations and the use of intraruminal controlled release devices containing Cr2O3 to determine faecal dry matter output. The intake of 137Cs was estimated by assuming an apparent absorption coefficient appropriate to the herbage grazed. The methodology has the advantage that sampling of herbage representative of that ingested by study animals is not required. Caesium-137 dietary intake explained >60% of the observed variability in the 137Cs activity concentration determined in the muscle of sheep. Resultant transfer coefficient (Ff) values to describe the transfer of 137Cs from the diet to muscle were in agreement with previously reported values. At one farm, there was a positive correlation between the 137Cs activity concentration in muscle and Ff whilst at the other farm there was a negative correlation between Ff and 137Cs dietary intake. Potential reasons for these observations are discussed.
本文描述了一项研究，该研究对位于英国西北部坎布里亚郡西部的两个农场中自由放养绵羊摄入的¹³⁷Cs进行了估算，这两个农场是英国切尔诺贝利事故沉降物量最高的地区之一。通过粪便中¹³⁷Cs活度浓度以及使用含有Cr₂O₃的瘤胃内控释装置来测定粪便干物质产量，从而估算¹³⁷Cs的粪便排泄量。通过假定一个适合所采食牧草的表观吸收系数来估算¹³⁷Cs的摄入量。该方法的优点是无需对研究动物所采食的具有代表性的牧草进行采样。¹³⁷Cs的膳食摄入量解释了绵羊肌肉中¹³⁷Cs活度浓度观测变异性的60%以上。用于描述¹³⁷Cs从日粮向肌肉转移的最终转移系数（Ff）值与先前报道的值一致。在一个农场，肌肉中¹³⁷Cs活度浓度与Ff之间呈正相关，而在另一个农场，Ff与¹³⁷Cs膳食摄入量之间呈负相关。本文讨论了这些观测结果的潜在原因。
