DEPOSITION AND INITIAL TRANSLOCATION OF INHALED PARTICLES IN SMALL LABORATORY ANIMALS

Approximately 1000 mice, rats, and guinea pigs were exposed to aerosols contaminated with 144Ce, 137Cs, 131I, or 85Sr to determine initial whole-body deposition and distribution in tissues. Aerosol vector was altered, in both generator solution concentration and chemical compound, to produce particle size distributions ranging from 0.33 μ to 3.7 μ activity median aerodynamic diameter (AMAD) and different relative solubilities. Accurate individual deposition values were obtained by recording the respiratory pattern of each animal during exposure. In rats and guinea pigs, initial total deposition increased with increased particle size; however, with particle size distributions from 0.7 μ to 2.5 μ AMAD, mice showed decreased deposition with larger particles. Initial distribution of inhaled materials in tissue was determined to be a function of particle size and solubility. © 1969 Health Physics Society.