Chemical and mutagenic properties of asphalt fume condensates generated under laboratory and field conditions

Exposure to asphalt fumes is widely recognized as a potential occupational health concern for paving and roofing workers. Two studies suggest that asp halt fumes generated in the laboratory art: carcinogenic to mice. In this s tudy, asphalt fume condensate (AFC) was collected from the head space of an operating hot mix asphalt storage tank and from a laboratory fume-generati ng apparatus operating at approximately 149 degrees C and 316 degrees C. Sa lmonella assays for mutagenesis, in vitro chromosomal aberration assays usi ng Chinese hamster ovary (CHO) cells, chemical analyses, and simulated dist illations were performed using gas chromatography to characterize the toxic ological and chemical properties of AFCs generated by these two methods. Th e 316 degrees C lab AFC sample was more mutagenic in the Salmonella assay t han the 149 degrees C lab AFC sample, with mutagenicity indices (Mls) of 8. 3 and 5.3, respectively. AFCs collected from the storage tank were nor muta genic. Chromosomal aberration assays of all AFCs were negative. Chemical an alyses and simulated distillations showed substantial differences in the ch emical composition of the AFC samples. The 316 degrees C lab AFC sample con tained more higher-boiling-point (three- and four-ring) polycyclic aromatic sulfur heterocycle compounds than the 149 degrees C lab AFC sample, and bo th lab AFC samples contained 5 to 100 times more of these compounds than AF C samples collected from the asphalt storage tank. These results are consis tent with other data reported in the scientific literature describing the c arcinogenicity of higher-boiling-point sulfur heterocycle compounds, In con trast to other recent studies, the results of this study indicate that the chemical composition and toxicological properties of laboratory-generated a sphalt fumes are not representative of those properties of fumes to which w orkers and the public might be exposed. (C) 2000 Elsevier Science B.V. All rights reserved.