Abstract
High volume fixed location samples of particles and vapor phase components were collected on filters and XAD-2 resin, respectively, to study the concentration and mutagenicity of diesel exhaust in locomotive repair shops at four railroads. The geometric mean concentrations were 96 μg/m3 [geometric standard deviation (GSD) = 2.14] for 23 samples of respirable particles, 164 μg/m3 (GSD = 1.86) for 26 samples of total particles, and 432 μg/m3 for 9 samples of vapor phase components. Approximately 30 to 40 percent of the particle mass was extractable in dichloromethane. Chemical class separation of these extracts by normal phase liquid chromatography yielded nearly half the mass in the aliphatic fraction, less than one third in the aromatic fraction, and about one quarter in the polar fraction. Extracts of particle samples were found to be mutagenic in the Salmonella typhimurium forward mutation assay system. Most of this activity was in the polar fraction. None of the vapor phase samples tested contained significant mutagenic activity either with or without metabolic activation. The locomotive repair shop air was approximately 1 order of magnitude more mutagenic than urban air. These elevated levels of mutagens found in diesel locomotive repair shops are consistent with the increased mortality from lung cancer that has been found among railroad workers. Hammond, S.K.; Smith, T.J.; Woskie, S.R.; Braun, A.G.; Lafleur, A.; Liber, H.; Garshick, E.; Schenker, M.B.; Speizer, F.E.: Railroad Diesel Exhaust: Concentration and Mutagenicity. Appl. Occup. Environ. Hyg. 8(11):955–963; 1993.