Radionuclides in Milk

Monthly milk samples from the milk sheds serving Atlanta, Austin, Chicago, Cincinnati, Fargo-Moorhead, New York City, Sacramento, Salt Lake City, Spokane, and St. Louis were analyzed for Ca and K content, I/sup 131/, Ba/sup 140/ s, Cs/sup 137/, Sr/sup 89/, and Sr/sup 90/. Analysis of variance applied to these data indicated geographical and seasonal variations. The average Sr/sup 90/ and Cs/sup 137/ content of milk samples from Sacramento was the lowest, while that from St. Louis was the highest. The remaining stations were grouped into one of two intermediate categories. Samples collected during early spring and fail showed higher Sr/sup 90/ and Cs/sup 137/ than at other times, probably associated with changes in seasonal feeding practices. No relationship was observed between the concentration of Sr/sup 90/ and Cs/sup 137/ in milk and publicly announced weapons tests. In contrast, a direct relationship was observed between the weapons tests and the concentration of I/sup 131/, Ba/sup 140/,, and Sr/sup 89/, which was influe nced by the half life of the radionuclides, the meteorological conditions, and the geographical location of the sampling stations with respect to the test site. Observed concentrations of radionuclides were below maximum permissible concentrations. Impracticability of estimating concentration ofmore » Sr/sup 90/ in milk, in terms of gross beta -activity or Cs/sup 137/, is discussed. (auth)« less