A type of fuel shown to decrease combustion emissions vs. traditional diesel is the diesel-water emulsion. Utilizing a collaborative approach, a toxicological assessment of the exhaust of PuriNOx fuel emulsion was recently conducted. Whole exhaust from one of two, 2001 model Cummins 5.9L ISB engines was diluted to exposure levels of 100, 200, and 400 g 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 and small increases in platelet values were treatment related. 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 and platelet results, the 100 g/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