Document wD7ZVEmjveo9M02aQEyQNV6V

THE UNIVERSITY O F TENNESSEE KNOXVILLE 37916 d e p a r t m e n t o f p h ys ic s a n d a str o n o m y September 1 6, 1968 Robert A . Kehoe, M.D. University of Cincinnati The Kettering Laboratory College of Medicine Eden Avenue Cincinnati, Ohio U521 9 Dear Doctor Kehoe: Thank you for your letter of September 6, 1968. I hope you will soon have time to examine at least the first few paragraphs of the revised paper I sent you because it describes in more detail the method of collection of the samples of diets and excreta from your men and I want to be sure it is correct. The referee felt that the first version was toe terse. The information that we are obtaining from your unique material is forming the basis for values for the daily intake and excretion of "Standard Man". It is wonderful that we have the opportunity tc analyze dally diets and excreta cf individuals ever such a long period. More and more I realize how fortunate we are in having you ar.i your group make tills material available to us. As a physicist and a member cf the ICEP task group on Standard Man I feel that my job is to make as careful and accurate analyses as possible and tc report what we find as clearly as I can. Although I do take the responsibility for the statistical treatment of the data, the interpretation cf the biological signifi cance of our results I must leave to these of you who have training in the field. As I see it, part cf the difference between you and Harry Schrceder arises fr-cm the fact that you are talking about two different things. Your interpretation is based fer tne most part on analysis of body fluids from living individuals under carefully control! conditions .nd ills on the analysis of tne actual tissues themselves cf random individuals who may be considered as representing a sample, however small, of the ordinary population Each cf you makes a logical Interpretation of the data before you, and I do net see that the data are Incompatible. It is difficult to assess tody burden on the basis of blood ar.d urine levels and, cf course, impossible to estimate rate of exposure from analysis of tls s u e 5 from cadavers. It seems tc me, however, that the Important difference between you is the same as tr.at between Rcbiey D. Evans and Karl Z. Morgan on the subject of ionizing radiation. That is you and Dr. Evans state that there is a threshold below which the accumulation of lead (0 Ionizing radiation) is "harmless" and Harry Schrceder a.nc Karl Morgan believe.that, althc ugh the body can tolerate and adjust to lower levels of exposure, the long range effects are vie b 00 I Robert A. Kehoe 2- - September l6, 1968 not negligible and so one cannot say that the low-level exposure is "harmless". In the case of ionizing radiation I feel that the evidence for the latter position is stronger than that for the former, and I am inclined to feel that way about trace metals as well. As yo u know, good solid information on long-range effects of anything Is difficult to come by, and even more difficult to interpret. One can hope that the heat and light generated by free discussion of these differences in philosophy will continue to stimulate research in the field for a long time so that the picture will become clearer as time goes on. Again I thank you for your long letter. Do you mind if I send a copy to Harry Schroeder? I wish we could all get together for a face-to-face discussion some time. I shall look forward to having your comments on the paper we sent you. With kindest regards, Sincerely, V. ' * - p- f'J /?>.'-- Isabel H. Tipton, IPh.D. Professor of Physics IHT: mw 1 - - ... > - ft v. 5 I 00513