swee; 4 to 6 cycles per second. The probability of « particle remaining within one millimeter sone for aa much as one-half hour appears to be vanishing small. ... Protection will also be provided by the muous lining which 4s itself renewed several times an hour." Accepting the estinates above and rad metbods illustrated in appendices E and F, it nay be conyuted thet about $3 reps would be delivered to the surface ef an imaging ary stationary sphere one millimeter ts radius by a 20 micron particle (@¢.2° steromerts)"ge doses Liat ‘be detivered closer to the particle but with the relatively rapid movement of the particle, it does net that large doses will be delivered tc a great muxber of cells. appear Maltiple ex;osures might oecur from efiitional particles but again this risk 4s difficult to evaluate. Food Considerable effort is being directed toward the study of eontam ination of food froz fallout. One element of major concern is Sr™, It has been estimated thet if one vere to subsist entirely onbyeeon froz sceils containing about, one xicrocurle per square foot of Sr (1,000 pounds of ealciun per acre}, that over a period of years there would accwmlate in the huran skeleton a body burden of one xicrocurie of Sr°*, Soils taken fror. ® about Files fron the Nevada froving Grounds, now show a concentration of microcuries per square foot. *irivate communication, L. 4. Dean, U. 5. Departnent of agriculture, Beltsville, Maryland, April 23, 195... es Wm wa ‘ “> aeeels =e