UNCLASSIFIED higher than that received by the respiratory system. The integrated dose received by the large intestine over the 28-day experimental period was twice that received by the respiratory system, stomach or small intestine. The finding that the G.I, tract can serve as a portal of entry for sol- uble fission-product aerosols following an inhalation exposure implies that an evaluation of the internal hazard associated with an inhalation exposure must take into account those parameters which influence transport across the G.J, membrane as well as the more commonly considered factors which determine transport across the alveolar membrane, Approved by: et POA. ABEBEL be,oe Captain (MC) USN Acting Head, Biological and Medical Sciences Division For the Scientific Director -20UNCLASSIFIED EK &© £B & FE & FE FF F 2 £& £E 2 wn £ F &