A Comparison Of The Skin Carcinogenicity Of Condensed Roofing Asphalt And Coal Tar Pitch Fumes.
Niemeier-RW; Moss-CE; Burg-J; Thayer-PS; Menzies-KT; vonThuna-P
The relative skin tumorigenicity of condensed volatile fumes from types 1 and 3 petroleum asphalt and types 1 and 3 coal tar pitch were applied twice weekly to the skin of male CD-1 and C3H/HeJ-mice for 18 months. The fumes were generated at two temperatures, 232 or 316 degrees-c and the condensates were applied to the skin in the presence or absence of simulated sunlight. Positive controls were treated with benzo(a)pyrene (50328) (BaP) in the presence or absence of sunlight. The condensates were analyzed. Petroleum asphalt fumes contained primarily aliphatic hydrocarbons, whereas coal tar pitch fumes contained mostly aromatic compounds. The animals were observed for tumor development. Survival was recorded. Mean survival times of treated animals were: C3H/HeJ-mice, 44.3 to 68.7 weeks and CD-1-mice, 52.6 to 67.8 weeks. Tumors were induced by condensed fumes from both types of asphalt and coal tar pitch. The incidence of all malignant tumors was lower in CD-1-mice. Most of the malignant tumors were squamous cell carcinomas. Most of the benign tumors were papillomas. Condensates of fumes generated at 316 degrees were more tumorigenic than those obtained at 232 degrees. Simulated sunlight generally had an inhibitory effect on the rate of appearance of tumors and final tumor incidence. The condensed coal tar pitch fumes had more carcinogenic activity than the asphalts. The authors note that the carcinogenic activity of roofing coal tar pitch fume materials may be understandable in terms of their BaP content. BaP is a satisfactory indicator for estimating relative coal tar pitch fume exposures in roofing operations. Further research is necessary before the active components of asphalt fumes can be identified.
Laboratory-animals; Mutagenicity; Chemical-properties; Laboratory-techniques; Skin-disorders; Toxic-materials; Carcinogenesis;
Proceedings of the Third NCI/EPA/NIOSH Collaborative Workshop: Progress on Joint Environmental and Occupational Cancer Studies