Variations in the Retention and Excretion of ¹³⁷Cs with Age and Sex

Abstract

THE biological behaviour of ¹³⁷Cs is important in measuring the dose received by the general population from fallout as well as that received by an individual from a specific uptake. Estimates of biological half-life^1–4 differ because only small population groups were studied. A correlation between ¹³⁷Cs concentrations (with respect to K) in milk and in the body indicates that ¹³⁷Cs in children between 5 and 11 has a much shorter biological half-life⁵. This article reports a four-year study to determine the biological behaviour of ¹³⁷Cs in 110 people representing a cross-section of the general population. The study population was grouped as shown in Table 1. The content of ¹³⁷Cs in the body was measured in the whole body counter at the Savannah River Laboratory. Adults were counted monthly; adolescents and children were counted every other month. A urine sample was collected from each subject within several days after their whole body count and analysed for ¹³⁷Cs and ⁴⁰K. The combined body counts and analysis of the urine provided a material balance between assimilation, retention and excretion of ¹³⁷Cs. To provide a common denominator and eliminate the inconvenience of obtaining 24-h urine samples, ¹³⁷Cs content is expressed per g of potassium, a chemically similar element.