Classes of compounds responsible for mutagenic and cytotoxic activity in tars and oils formed during low BTU gasification of coal

The Lovelace Inhalation Toxicology Research Institute (ITRI), in cooperation with the Morgantown Energy Technology Center (METC), has completed toxicity screening of vapors, liquids and solids formed during operation of an experimental pressurized, stirred-bed, coal gasifier at METC. Vapors collected from the cooled process stream on Tenax resins had no mutagenic activity in the Ames Salmonella assay. Dichloromethane extracts of liquids and solids collected from the effluent or process streams were fractionated by gel chromatography into fractions containing mostly aliphatic compounds; neutral polycyclic aromatic hydrocarbons (PAH); polar (PAH) and heterocyclic compounds; and salts. The polar fraction was partitioned into acids, bases, water soluble compounds and phenols. Bacterial mutagenic activity was highest in the basic fraction with additional activity in the neutral PAHs. Highest cytotoxicity toward both the bacteria and canine alveolar macrophages was in the phenolic fraction. Treatment of the gasifier tars by nitrosation or by acetylation to remove primary aromatic amines (PAA) reduced the bacterial mutagenicity by 50-60%, indicating that some, but not all, of the mutagenicity was due to PAA.