Pneumoconiosis in Rats Exposed Chronically to Oil Shale Dust and Diesel Exhaust, Alone and in Combination

Rats were exposed by chronic inhalation to diesel exhaust or oil shale dust, alone and in combination to examine pathophysiologic interactions between the dusts. The three agents all accumulated progressively in lungs and caused similar pneumoconiotic responses. The effects of combined exposures tended to be greater than additive. The magnitude of effects was more closely correlated to particle lung burden than to exposure concentration. This suggests that effects of prolonged human exposures to combined dust atmospheres may be estimated better on the basis of predicted lung burden than exposure concentration. 14 refs., 2 figs., 2 tabs.