The pulmonary toxicity of an ash sample from the MT. St. Helens Volcano.

Volcanic ash was collected from the Moses Lake region of Washington State after the 18 May 1980 eruption of Mt. St. Helens. The ash was tested in a short-term bioassay system using hamsters exposed by intratracheal instillation. One day after exposure the lungs were lavaged and the fluid collected was characterized using several parameters that represent different manifestations of lung injury: (a) in situ phagocytic ability of pulmonary macrophages; (b) the inflammatory response, as shown by polymorphonuclear neutrophil numbers and albumin levels in lung lavage fluid; and (c) release of cytoplasmic and lysosomal enzymes into the cell-free supernatant of lung-lavage fluid. The response to volcanic ash was elevated compared to controls, but was similar to the response to Al2O3, a dust considered to be relatively inert. In contrast, the response to alpha-quartz, a highly toxic fibrogenic dust, was significantly greater than the response to either volcanic ash or Al2O3 for most parameters measured.