Sumerling T J, Dodd N J, Green N
Sci Total Environ. 1984 Mar 1;34(1-2):57-72. doi: 10.1016/0048-9697(84)90041-x.
A field investigation of the transfer of artificially produced radionuclides in the pasture--cow--milk pathway has been made at a farm close to the nuclear fuel reprocessing installation at Sellafield on the north-west coast of England. This paper reports results from analyses of samples collected during 1981, reports transfers coefficients for 90Sr and 137Cs from various types of feed to milk, and discusses factors that affect the transfer of these radionuclides. It is shown that during 1981 a large proportion of the 90Sr and 137Cs consumed by cattle grazing near Sellafield was derived from activity deposited in previous years. Transfer coefficients to milk, Fm, have been derived which are within the ranges of those observed in tracer and fallout studies. There are significant seasonal changes in transfer. For 90Sr, values of Fm between 9 X 10(-4)d 1(-1) and 4 X 10(-3)d 1(-1) have been obtained. It is concluded that this large range arises because daily intakes of 90Sr by the herd during the winter months are lower (by a factor of about 3) than intakes during the summer months and that the concentration of 90Sr in milk is not in equilibrium with intake, that is, the concentration of 90Sr in milk is maintained both by recent intakes and by remobilisation of activity that has been accumulated in bone from earlier intakes. For 137Cs, values of Fm between 3 X 10(-3)d 1(-1) and 9 X 10(-3)d 1(-1) have been obtained. It is concluded that this range most probably occurs because during the summer months, when the cows are grazing, a substantial proportion of the 137Cs intake is associated with soil on the surface of herbage and that, in this form, the 137Cs is less available for uptake from the digestive tract of the cows.
在英格兰西北海岸塞拉菲尔德核燃料后处理设施附近的一个农场，对人工制造的放射性核素在牧场—奶牛—牛奶途径中的转移进行了实地调查。本文报告了1981年期间采集样本的分析结果，报告了90锶和137铯从各类饲料到牛奶的转移系数，并讨论了影响这些放射性核素转移的因素。结果表明，1981年期间，在塞拉菲尔德附近放牧的牛所摄入的大部分90锶和137铯来自前几年沉积的放射性物质。已得出牛奶的转移系数Fm，其在示踪剂和沉降研究中观察到的范围内。转移存在显著的季节性变化。对于90锶，已获得的Fm值在9×10⁻⁴d⁻¹至4×10⁻³d⁻¹之间。得出结论，这个大范围的出现是因为冬季牛群每日摄入的90锶量低于（约为其三分之一）夏季摄入量，且牛奶中90锶的浓度与摄入量不平衡，即牛奶中90锶的浓度既由近期摄入量维持，也由早期摄入量在骨骼中积累的放射性物质的再迁移维持。对于137铯，已获得的Fm值在3×10⁻³d⁻¹至9×10⁻³d⁻¹之间。得出结论，这个范围很可能是因为在夏季奶牛放牧时，所摄入的137铯中有很大一部分与牧草表面的土壤相关，且以这种形式，137铯从奶牛消化道吸收的可用性较低。
