ho Inhalation probably can nct account for the total metabolized activity bus its contribution may be significant. No evidence of gress pathology or lesicns were noted as a result of extreme radiation exposure to native animals living in envirenments contaminated at levels of several hundred R, infinite dose, A correlstion did exist between environmental contamination and uptake of activity by native rodents suggesting the valld use of native rodentc as indicators of biclogically available activity resuiting from Fall-out deposited at distances less than twenty miles from Ground Zero. This Division suggests a five point project to obtain specific field data to answer questions posed by the above summary and concurrent labo~ ratory work . Le Biological Hanitoring This woald invelve the sampling of native rodents from sel= ected areas of maximmm contamination by Fall-out, at various distances (less than 120 miles from Ground Zero), to determine relative animal uptake as a function of the physical character- istics of Fali-out; and to provide refined data with which to compare environmental decay rate, tissue decay rate, and decay rates determined by serial sempling of native populations, to batter define the true relation of metabolic activity to en= vironmental activity. Availability of Activity An effor> will be made to daterzine the metabolic availability of both primary Fall-out and air-borne particles of early fission materials. This includes the identification ‘of isotopes involved, degres of contamination of forage crops, the uptake DOS ARCHIVES