Mathematical Modeling of Silicon Carbide Whisker Deposition in the Lung: Comparison Between Rats and Humans

Abstract

In this study, we use silicon carbide whisker (SiCw) as a model of the refractory ceramic fibers that are similar in size and shape to asbestos. If these fibers were airborne, they could be inhaled and deposited in the respiratory system. Of major concern is the association between the retention of inhaled fiber and fiber-related diseases, such as lung fibrosis and lung cancer. This paper reports the deposition efficiencies of SiCw in the respiratory system calculated from theory. The deposition efficiencies for SiCw were calculated for the head airways, the conducting airways (tracheobronchial tree) and the air-exchange region (alveolar region) of the lung for man and for the Fischer 344 rat. Based on the calculated deposition efficiencies and the size distribution of SiCw, we estimate that should it become airborne, SiCw could deposited in the sensitive tissues of the alveolar region (11–17% fiber count) and tracheobronchial tree (5–20% fiber count).