RADIOSTRONTIUM TRANSFER TO SHEEPS MILK AS A RESULT OF SOIL INGESTION

Soil ingestion as a source of radiostrontium contamination of ruminant milk products was studied by measuring the transfer coefficient to ov ine milk. This is a follow-up report from a previous experiment (Assim akopoulos et al., 1993), which investigated radiocaesium transfer to s heep's milk as a result of soil ingestion. Milk samples from three lac tating ewes, housed in individual metabolism cages, were used. Fifty g rams per day of heavily contaminated sandy topsoil, collected in the C hernobyl area, were administered orally to the animals for a period of 1 week. The daily intake of Sr-90 was 78 Bq day(-1). During this cont amination period, daily milk production and excreta output were measur ed. Excreta and milk was collected for an additional 7-day decontamina tion period, while they were fed on uncontaminated feed. The transfer coefficient was obtained through a best fit (minimum chi(2)) of the da ta to predictions of a linear compartment model. The value obtained wa s f(m) = 0.041 +/- 0.016 d kg(-1) for radiostrontium transport to milk . This result suggests that soil ingestion can be a major source of ra diostrontium contamination in sheep and other free-grazing ruminants.