Mutation Research, 245 (1990) 177-183 177 Elsevier MUTLET 0416 Evaluation of the mutagenicity of combustion particles from several common biomass fuels in the Ames/Salmonella microsome test Douglas A. Bell* and Richard M. Kamens Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27514 (U.S.A.) (Received 16 January 1990) (Revision received 18 June 1990) (Accepted 19 June 1990) Keywords: Biomass fuels; Indoor air; Combustion particles; Dichloromethane extracts Summary We have evaluated the mutagenicity of dichloromethane extracts of combustion particles from several biomass fuels that are commonly used in developing countries in Salmonella strains TA98+__$9 and TA100 + $9. Combustion-particle extracts from dried cow dung and crop residue exhibited mutagenic poten- cies similar to wood-smoke extracts (0.0-1.0 rev.//zg extract). However, extracts from coconut-shell-smoke particles showed relatively potent direct-acting mutagenicity (1.6 rev.//~g, TA98 - $9). Results from testing this sample in nitroreductase- and acetylase- deficient strains TA98NR and TA98 (1,8-DNP-6) revealed no contribution from nitroarenes. Biomass fuels are significant energy sources for heating and cooking in the developing countries of the world. Historically, wood has been the primary biomass fuel but with deforestation in the densely populated areas of Asia and Africa, the use of agricultural residues such as dried animal dung and crop by-products has become increasingly common (Barnard, 1985). Hughart (1979) estimated that more than 800 million people in the developing * Present address: Laboratory of Biochemical Risk Analysis, C3-03, National Institute of Environmental Health Sciences, P.O. Box 12233, Research Triangle Park, NC 27709 (U.S.A.). Correspondence: Dr. D.A. Bell, C3-03, Laboratory of Biochemical Risk Analysis, NIEHS, P.O. Box 12233, Research Triangle Park, NC 27709 (U.S.A.). countries routinely use agricultural residues for fuel. These fuels, including dried cow dung, coconut shell and husk, rice and other cereal straws, tobacco stalks, and jute sticks are often burned in open fires or unvented cookstoves inside the home. The resulting human exposures to com- bustion gases and particles from indoor burning can be 100-fold higher than pollutant levels typical- ly experienced in polluted urban air (Smith et al., 1983; Mumford et al., 1987). Human health effects from exposure to high indoor-smoke levels include acute respiratory disease, chronic bronchitis and other chronic respiratory illnesses, and infant mortality (de Ko- ning et al., 1985; Pandey, 1985). The genotoxic ef- fects from exposure to smoke from agricultural 0165-7992/90/$ 03.50 © 1990 Elsevier Science Publishers B.V. (Biomedical Division)