Lignite and the Derived Steam-Activated Carbon

Abstract

The pulmonary response to 2 dusts of respirable size, 1 consisting entirely of lignite and the other, a derived commercial steam-activated carbon used as an adsorbent (DARCO), was investigated on 4 species of animals: monkeys, guinea pigs, rats, and mice. The pulmonary response to both dusts in all 4 animal species was of the type which classifies both dusts as inert. No significant difference was noted in the response to the 2 dusts. An inert dust is defined as one which produces a pulmonary response having the following features: collagenization is absent or insignificant in the reacting lung tissue; there is continued anatomic integrity of the air spaces in spite of the presence of dust in the latter; the lesions are potentially reversible. The pulmonary reactions observed in the experimental animals exposed to both dusts fulfill the above require-ments. Lipid pneumonia development in rats, and the paucity of pulmonary dust deposits in mice are examples of species linked peculiarities in pulmonary response to dusts. The last may be the result of an extraordinarily efficient alveolar clearance mechanism in mice.