Exposure to External and Internal Radiation Project Title: 17. Evaluation of Hazards from Tritium--Dominant Lethal Mutations in Mice RX-01-O01-(c) Expected Results in FY 1974: (Cont'd.) cause genetic damage as measured by the dominant lethal test. Additional evaluations of the hematopoietic system will be made at various times to determine whether there is an effect on the bone marrow. Due to budget Limita- tions, the histological examinations of the embryos which was indicated as a part of this program in last year's budget report have not been undertaken. It is hoped that work on this phase of the project might be started, 18. Expected Results in FY 1975: This program will continue and data will be accumulated on the effectiveness of both tritiated water and X-ray exposures in producing dominant lethal mutations, Studies evaluating the effects of both treatments omthe hematopoietic stem cell pool should also be completed. 19, Description and Explanation of Major Materials, Subcontract Items: Equipment and None 20, Proposed Obligations for Related Construction Projects: 4 f toy None RX- 27 L119181