Methodology for Estimating Electron Doses to Skin of Atomic Veterans rrom Dermal Contamination
A.I. Apostoaei and D.C. Kocher (SENES Oak Ridge, Inc.)
Many military personnel who participated in the atmospheric nuclear-weapons testing program (atomic veterans) were subjected to contamination of skin and clothing by radioactive particles, and such contamination could have been an important contributor to external doses to skin. This presentation describes a methodology for estimating contamination of skin and clothing by deposition of descending or resuspended fallout from a nuclear weapon detonation or by contact with contaminated ground and other surfaces. Modeling of contamination by direct contact relies on relevant data on soil loading on skin and clothing. Modeling of contamination by deposition is based on estimates of the fraction of incident material that is intercepted and retained on various surfaces of the body. Interception and retention fractions are derived from measurements of accumulation of ash particles on the ground surface and on different parts of the body following volcanic eruptions. These fractions are adjusted to account for an enhancement in retention when hair and moisture are present on skin. Retention of particles on skin decreases with increasing particle size for particle diameters greater than 50 microns. Since skin preferentially retains small particles, the specific activity of retained material is enhanced compared with the specific activity of material incident on the body when radionuclides are distributed on the surface of particles. Skin contamination due to resuspended material increases with increasing wind speed and exposure duration. We present example calculations of skin doses obtained using uncertainty analysis techniques for specific exposure scenarios at the Nevada Test Site and Pacific Proving Ground. For exposure to descending fallout or resuspended material, electron doses to skin from dermal contamination can be a significant and sometimes dominant contributor to the total skin dose from all exposure pathways.