UNITED STATES ot ATOMIC ENERGY COMMISSION WASHINGTON. D.C. 20545 Oct 201999) ‘ ‘ ww 444." ,- cf / a, . J Lev . 7% C x, pat LL 4% (Bilder e Joseph J. DiNunno, Special Assistant to the General Manager for Environmental Affairs pa os REPLY TO QUESTIONS RAISED BY DR. ISBIN This is in reply to your memorandum of October 16, 1969, requesting answers to three questions raised at the University of Minnesota Symposium on October 11, 1969. The response to question 2 is contained in a memorandum from Gordon M. Dunning to Howard Brown, copy to you, dated October 14, 1969. The information referred to in question 3 is contained in the AEC's Semiannual Report to Congress dated January 1953, covering the time period July-December 1952. The pertinent quotation is found on page 122 of that report: "Cattle absorb 25 to 30 percent of the ingested strontium, with about 25 percent reaching the bone. A few days after entrance of radiostrontium into the body, about 99 percent of the remaining amount will be in the bones. The only potential hazard to human beings would be the ingestion of bone splinters which might be intermingled with muscle tissue during butchering and cutting of the meat. An insignificant amount would enter the human body in this fashion." Up until the end of 1952 the most pertinent data were on strontium-90 in fetal bones developed by Dr. W. F. Libby. The values were so low that there was no particular reason to hasten to inaugurate an extensive monitoring of the environment. Even in late 1953 and early 1954 when measurements of strontium in milk were initiated, the concentrations of strontium-90 were indeed quite low. For example, in early 1954 the highest values of strontium-90 in milk were only about 1/2 picocurie per liter of milk. It is correct that as time went on it was appreciated more fully the role that milk might play in the uptake of strontium-90 by man and the analyses effort was expanded accordingly. In regard to your first question, it is not clear what data are being referred to. On pages 11 and 12 of Dr. Commoner'’s speech he states, Boe, VES ,