Lifetime accumulation of (137)Cs and (40)K in the ribs and sternum of an Austrian "mountain pasture" cow

The accumulation of natural and artificial radionuclides in humans and domestic animals is of interest in estimating effective doses of exposed humans and to decide whether animal products can be used for nutrition of the population. In this paper we present an investigation of the (137)Cs- and (40)K-activity levels of the ribs and sternum of a "mountain pasture" cow, born in a highly contaminated region of Styria, Austria, at the time of the radioactive fallout following the Chernobyl accident. This is the first systematic investigation of the variation in activity levels of a contaminated animal. The International Commission on Radiological Protection (ICRP) assumes that cesium and potassium are homogenously distributed throughout the whole body of an organism. However, the presented results show that there is a non-uniform distribution of (137)Cs and (40)K in different skeletal bones and their adherent tissues of a dairy cattle. We found that activity concentrations of (137)Cs and (40)K varied up to a factor 2.5 in different components of the ribs. The minimum values of (137)Cs and (40)K in the ribs were 29.9 and 21Bqkg(-1) fresh mass for trabecular bone in the vertebral half of asternal ribs, and the maximum values 332 and 132Bqkg(-1) fresh mass for a mixed sample composed of a cartilaginous tissue layer and parts of the perichondrium, both originating from asternal costal cartilages, respectively.