Pulmonary response following intratracheal instillation of potroom dust from an aluminum reduction plant into rat lung.

Rats were examined for lung changes 7 days and 22 weeks after a single intratracheal instillation of potroom dust from an aluminum reduction plant. In the acute study, 0.5 mg potroom dust induced changes at the pulmonary surface, and a 5.0-mg dose caused marked changes both at the pulmonary surface and in lung tissue. By contrast, 5.0 mg virginal alumina caused only a mild increase in the number of polymorphonuclear leukocytes in the lung. In the long-term study, potroom dust, virginal alumina, and DQ12 alpha-quartz were instilled at a dose of 5.0 mg. In the cases of potroom dust and virginal alumina, all parameters measured had returned to control levels after 22 weeks, whereas DQ12 induced a massive inflammation and an accumulation of pulmonary surfactant. It is concluded that this air sample of potroom dust causes marked acute irritation and inflammation in rat lung and that this type of dust may therefore be active in human lung and thus contribute to the acute respiratory symptoms experienced by some potroom workers. However, despite the marked acute toxicity of the comparatively high 5.0-mg dose, rat lung appears to return to normal within 22 weeks with no signs of chronic toxicity from this single instillation.