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EPA Research on Health Effects of Biofuels: Studies with inhaled ethanol in rats.
Citation:
BUSHNELL, P. J., T. E. BEASLEY, W. K. BOYES, H. A. EL-MASRI, P. A. EVANSKY, J. Ford, W. R. LeFew, S. A. Martin, K. L. McDaniel, M. E. GILBERT, E. MCLANAHAN, D. K. MacMillan, V. C. MOSER, AND D. W. HERR. EPA Research on Health Effects of Biofuels: Studies with inhaled ethanol in rats. Presented at Neurobehavorial Teratology Society Meeting, San Diego, CA, June 25 - 29, 2011.
Impact/Purpose:
This research project will address the potential for neurological and immunological effects from developmental exposure to evaporative emissions from ethanol gasoline blends.
Description:
The Energy Independence and Security Act of 2007 mandates increased use of alternative fuels in the American automobile fleet. Currently, the primary alternative to petroleum fuels is ethanol, and the public health risk associated with adding ethanol to gasoline at concentrations above 10% is uncertain. This research project will address the potential for neurological and immunological effects from developmental exposure to evaporative emissions from ethanol gasoline blends. It combines computational modeling and animal experimentation with a goal of estimating the developmental toxicity of inhaled vapors from gasoline blended with any concentration of ethanol. Modeling approaches include PBPK models parameterized for pregnant rats inhaling ethanol and complex mixtures of volatile components of gasoline. The experimental approach involves exposing pregnant female rats to vapors of ethanol and gasoline ethanol blends from gestational day 9 through 20; quantifying target-tissue doses (concentrations ethanol in blood and brain); and determining relationships between internal dose and effect in their offspring using behavioral, neurophysiological, and immunological assessments. Pilot studies demonstrated that pregnant female Long-Evans rats (N = 8/group) tolerated a high concentration of inhaled ethanol (20,000 ppm, 6 hr/day for 12 days) without apparent distress and delivered viable litters. No significant differences in maternal weight gain, litter size, or offspring brain weight were observed, nor was fear conditioning affected in the pups at postnatal day (PND) 60. However, exposed pups grew more slowly and performed a choice reaction time test less accurately than controls. In a larger study, pregnant rats were exposed under the same scenario to ethanol vapor at concentrations of 0, 5,000, 10,000, and 21,000 ppm (N = 18/group) and successfully delivered litters that did not differ significantly in size or weight. Assessment of offspring from this study is underway. Future studies will compare dose-effect relationships from this exposure to neat ethanol to those from exposure to vapor condensates of gasoline:ethanol blend ratios of 100:0,85:15 and 15:85. This abstract does not reflect EPA policy.