Deposition patterns of inhaled polydisperse aerosols in weanling calves

Abstract

Accurate estimation of effective dose received by an animal exposed to a given aerosol requires knowledge of the selective properties of the animal's respiratory system for trapping and retaining aerosol droplets of different sizes. The research reported in this dissertation was conducted to determine the deposition and retention patterns for inhaled aerosols relative to droplet size in weanling calves. The research involved (a) the design, construction, and evaluation of a "nose only" inhalation exposure system for exposing calves to respirable aerosols of known characteristics, and (b) the actual controlled exposures of weanling calves to polydisperse aerosols of ^C -labeled, mineral oil. Total aerosol deposition losses in the animals during exposures were determined by external measurements of respiration activity, and inhaled and exhaled aerosol concentrations. Shortly after exposure, each animal was killed and the lungs, trachea, and other body components were analyzed using radioassay procedures to determine the aerosol deposition patterns within the animals. ...