ee eee eee This laboratory, working in conjunction with the Beltsville gro order to further explore this possibility, the soils from five were analyzed for radium, as were the bones of the livestock, obtained are plotted in Figure 10. Radium determinations could|Jnot be completed on the Tifton samples because these arrived too late build up of daughter product activity following separation of +} 228. The four ratios obtained when plotted against reciprocal calcium do not show as clear a linear regression as was true fo strontium. This may be due to the fact that radium does not behave as stro ium does, or to analytical difficulty with the low radium concentrations soile The results are not completely discouraging and further work se jndicated, Comparison of Radiostrontium in Various Biological Materials Among the various materials which have been analyzed for radiost are soma which have in common the fact that the isotopes origina large extent from soils in the region of southern New York and n New Jersey, These samples include the lambs and calves from pas Ithaca and Rutgers, the New York City milk supply, human milk an borns from the metropolitan New York area, For the last two kin samples, the primary origin of the radiostrontiwm is, of course, in doubt but in human milk and stillborn alike there is likely to be a la fe con= tribution of calcium, and therefore strontium which has its ori in the soils from this area, Table 10 summarizes the results of analysis of these mterials. [It will be noted that the Sr°9799 activity when expressed in d/min/gm of fFalcium are of the same order, This is again a test of the constancy of the calciumsradiostrontibm ratio in caloium obtained from various places in the biological feeding chain. These samples have in common the faot that in one way or another he caloium was derived via vegetation, the calciwmsradiostrontium ragkio of which was determined by the cumulative fallout in the geographical area and the exchangeable calciwn of the soil. A more liberal samplink program and a more careful study of the dietary habits of humans in fhe area studied seem indicated,