Mutagenicity in salmonella of nitroorganic compounds in extracts of fly ash from a lignite‐fired atmospheric fluidized‐bed combustor

Abstract

The mutagenicity of a benzene/methanol extract of fly ash from an atmospheric fluidized‐bed combustor burning Beulah, N.D., lignite was tested in Salmonella. Six strains were used, including three that were mutants in a nitroreductase gene locus. The numbers of revertants from his⁻ to his⁺ as a function of the amount of fly ash extracted were determined. The results showed that the major mutagens in the crude extract were nitro compounds, from the fact that reversion rates in the nitroreductase‐deficient strains were significantly lower than in the parent strains from which they were derived. The responses of the three parental strains, TA 1538, TA98, and TA 100, were quite similar; thus no conclusions could be made about frameshift versus base‐substitution mutagens. Mutagenicity of 15 fractions of the extract was also tested, and one major peak of activity was detected. This activity eluted from a high‐performance liquid chromatograph outside the range of retention times associated with mononitro‐aromatics. No further identification of specific nitroorganic compounds has been made.