DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE PUBLIC HEALTH SERVICE R L003 7-7 FOOD AND DRUG ADMINISTRATION ROCKVILLE, MARYLAND 20852 January 24, 1973 3 pb af ad Dr. Nathaniel F. Barr Asst. Dir. for Measurement & Evaluation Div. of Biomedical & Environmental Research 3 nv ? tr U. S. Atomic Energy Commission Washington, D. C. 20545 5 Dear Nat: As I promised I'm jotting down several comments that came to mind at the recent Kniwetok Radiological Assessment Review Group. These comments may or may not prove to be important, but I think that they deserve some further attention and evaluation at this time. I urge you to cbtain some information on the particle size distribution of plutonium in surface soil, particularly in the so called "hot" areas. This information is essential for evaluation of the potential for particle redistribution by wind, and hence in determination of the potential for human inhalation. I would particularly sample those sites at which plutonium deposition originated by processes other than ordinary testing. Attention should also be directed toward evaluation of radionuclides which although they are not thought to be significant contributors to radiation dose under usual conditions may, because of the magnitude of the test program at Eniwetok have accumulated to a greater extent than in global fallout. Specifically I refer to 1291, 3H ana l4c. Sampling ‘and evaluation of these radionuclides need not be extensive unless a real problem is indicated by the initial results. Best personal regards. Sincerely yours, Nit Awbibe rf oroad wy * >th ~ [pom os . * o r’.- c 4 footo : eer ro mB Pe ae a uy oe oaa on aitat Oo seh, a3 Lo _. wg ge gtDee ol Ober fe, - Bernard Shleien Assistant to the Director Program Office Bureau of Radiological Health ce, at A sm oobaenhe ctf eee Lor. a i AA wo Lea uf pares. ap cen F qiee eehe . hth kewlLith pia 5005712 = ae L patiep cat ond Oe Y none ye tem. fe - Pole, 5 OC687