Toxic ranking of the <3 micrometer size fraction of particulate samples by in vitro rabbit alveolar macrophage assay showed generally low to intermediate cytotoxicity for samples obtained from a steel foundry, an electric arc furnace steel plant and from four coal-fired power plants. Particulates obtained from an aluminum and from a copper smelter were highly toxic to alveolar macrophages as monitored by viability, total cellular protein and ATP levels. The two smelter samples also contained soluble components that significantly contributed to their cytotoxicity. None of the particulate samples tested were true emission or effluent samples, but were collected from in-plant control devices. Inhalation of copper smelter particle aerosols produced significant changes in more of the parameters than inhalation of the coal fly ash. Thus, the overall objective of these studies was realized by demonstrating the validity of prediction of inhalation hazard on the basis of the in vitro screening assay.

Caption title. "January 1981." "EPA-600/1-83-003." Microfiche.