A type of fuel shown to decrease combustion emissions vs. traditional diesel is the diesel emulsion. Utilizing a collaborative approach, a toxicological assessment of the exhaust of PuriNOx fuel emulsion was recently conducted. Whole exhaust from one of two, 2002 model Cummins 5.9L ISB engines was diluted to exposure levels of 125, 250, and 500 ug particulate matter (PM)/m 3. The engines were operated on a repeating EPA heavy-duty certification cycle. F344 rats were housed in Hazleton H2000 exposure chambers and exposed to exhaust 6 h/day, 5 days/wk for the first 11 weeks and 7 days a week thereafter. Exposure days ranged from 58-70 days. Exposure- start was staggered to account for multiple health endpoints. Toxicological assays were conducted during and following exposures and subsequent to a recovery period. General toxicity (body weight, organ weight, clinical pathology, and histopathology), neurotoxicity (glial fibrillary acidic protein assay, GFAP), genotoxicity (Ames, micronucleus, sister chromatid exchange), and reproduction and development were assessed. Effects observed were mild. Exhaust was not associated with neurotoxicity, reproductive/developmental toxicity, or in vivo genotoxicity. Small decreases in serum cholesterol were noted in males and females of the high level exposure. PM accumulation within alveolar macrophages was noted in all exposure groups. Other sporadic statistically significant responses were observed but not clearly treatment related. Exhaust subfractions induced mutagenic responses in S. typh. Based on the cholesterol results, it can be concluded that the 250 ug/m 3 exposure level was the NOAEL. In general, these observations were consistent with rodent and bacteria exposure to petroleum diesel exhaust.
The Toxicologist. Society of Toxicology 43nd Annual Meeting and ToxExpo, March 21-25, 2004, Baltimore, Maryland