Toxicokinetics of ethyl tertiary-butyl ether (ETBE) and methyl tertiary-butyl ether (MTBE) in men and women.
NIOSH 2001 May; :1-39
Methyl tertiary butyl ether (MTBE) and ETBE are used as gasoline components to reduce tailpipe emissions in 39 areas of the United States which exceed the National Ambient Air Quality Standards for carbon monoxide and in the 9 metropolitan regions with the most elevated summertime ozone levels. MTBE and ETBE exposures occur during gasoline production and refueling, and as recently documented in California and Washington, potentially through contact with groundwater contaminated by leaking underground storage tanks. However, little is known about how the body handles MTBE, ETBE and their metabolites; nor about reliable biological indicators or occupational and environmental exposure. We conducted controlled exposures of men and women to 2.5 ppm 2H12-MTBE + 2.5 ppm ETBE for two hours with alternating periods of work and rest, and sampled blood, breath and urine during and for three days following exposure. Concurrently, a physiologically-based kinetic (KBK) model was developed to include data from other research efforts, to incorporate parameter variability through Bayesian fitting and Monte Carlo simulation techniques, and to determine a biological index of exposure Post-exposure blood and breath levels exhibited two half-lives for both 2H12-MTBE and ETBE of about 1 and 8.4 hours, and 1.5 and 10.6 hours, respectively. Tertiary-butyl-alcohol (TBA) breath concentration from each ether appeared to be a valuable index of exposure with a single half-life of 20-40 hours.
Pharmacodynamics; Metabolic-study; Metabolic-rate; Metabolism; Metabolites; Blood-analysis; Urinalysis; Biological-monitoring; Biologic-half-life; Biomarkers
Crispin H Pierce, PhD, University of Washington, Seattle, WA
1634-04-4; 75-65-0; 8006-61-9; 637-92-3
Final Grant Report
NTIS Accession No.
National Institute for Occupational Safety and Health
University of Washington, Seattle WA