In compliance with the Clean Air Act Section 211b for fuel and fuel additive registration, the petroleum industry and oxygenate manufacturers conducted comparative toxicology testing on evaporative emissions of gasoline alone and gasoline containing ether or alcohol oxygenates. Seven vapor condensates of gasoline (GVC), or gasoline-ether [MTBE (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE)], or alcohol [ethanol (G/EtOH), t-butyl alcohol (G/TBA)] were evaluated for reproductive toxicity in Sprague-Dawley rats. G/ETBE, G/TAME, G/DIPE, G/EtOH, and G/TBA were assessed for one-generation; GVC and G/MTBE were assessed over two generations. Additionally, GVC and G/MTBE offspring were evaluated for quantitative changes in regional brain glial fibrillary acidic protein (GFAP) content. All inhalation exposures were 6 h/d, 7 d/w, at levels of 2000 - 20, 000 mg/m3. All exposures increased male kidney weight consistent with light hydrocarbon nephropathy. In adult rats, frequent findings across exposure groups included decreased body weight gain and increased liver weight, most commonly in males. Spleen weight decreased with G/TBA. G/EtOH and G/TBA exposure resulted in higher prostate weight, but no pathological changes occurred to reproductive organs in any study. Except for de-creased food consumption during lactation (G/TAME) and a minor increase in time to mating (G/TBA), there were no reproductive findings. Offspring effects included reduced weight gain during lactation (G/TAME) and decreased spleen weight (G/TBA). Results of these studies will be used for comparative risk assessments of gasoline and gasoline/oxygenate blends.
The Toxicologist. Society of Toxicology 43nd Annual Meeting and ToxExpo, March 21-25, 2004, Baltimore, Maryland