Induction of micronuclei in V79 cells by fractions of roofing asphalt fumecondensate

More than 50,000 workers in the United States are exposed to roofing asphal t fumes that may pose genotoxic and potential carcinogenic hazards. The Typ e III roofing asphalt is most frequently used in roof-application. Results of our previous studies showed that fume condensates of Type III roofing as phalts induced micronuclei (MN) in vitro in cultured V79 cells and DNA addu ct formation in vivo in rat lung cells. In this study, the genotoxicity of whole fume condensates (WFC) of Type III roofing asphalt and its five chemi cal fractions (A, B, C, D and E) was determined by the micronucleus assay u sing V79 cells. Linear regressions were determined for the dose response of MN frequencies and percent of binucleated and multinucleated cells (MTC) f ollowing the treatment. Results showed that the numbers of micronucleated c ells in cultures treated with Type LU roofing asphalt WFC and its fractions B, C, D and E were significantly higher than that in the control culture, and that the slopes of the linear regression Line for fractions B and C wer e greater than those for the WFC and fractions D and E. A clear dose respon se of binucleated cells was also induced by the WFC and fractions B and C. These findings indicate that: (1) WFC and all fractions, except fraction A, induced MN formation in cultured V79 cells; (2) fractions B and C possess the highest genotoxic activity; (3) the roofing asphalt WFC contains chemic als or chemical classes that induce not only chromosomal aberrations but al so binucleation in V79 cells. (C) 1999 Elsevier Science B.V. All rights res erved.