Radioactivity of people and milk: 1957.

The routine determination of cesium-137 and potassium-40 content of over 2200 samples was accomplished through utilization of one-fifth of the potential capacity of the Los Alamos human counter. Little change in the cesium-137 concentration in people was observed from 1956 to 1957, in spite of the increase in both the rate and the integrated levels of fallout. The correlation of levels in human beings with cesium levels in milk indicates a discrimination factor of 1.8 in this step of the ecological transfer. Precipitation is shown to be an important factor determining the cesium content of milk, but the lack of complete correlation indicates that a more detailed analysis is necessary. Contamination of the troposphere during periods of weapon testing complicates the interpretation, as do seasonal variations.