Bioavailability of Volatile Organics and Other Hydrocarbons from EnvironmentalMedia: Ingestion in Drinking Water

摘要

The primary objectives of this project are to: (1) assess the roles of hepaticand pulmonary presystemic elimination in reducing the bioavailability of low levels of volatile organic chemicals (VOCs) found in drinking water supplies; (2) investigate gastrointestinal (GI) absorption pathways for VOCs; (3) characterize the influence of oil dosage vehicles on the absorption, pharmacokinetics (PK) and toxicity of VOCs, with emphasis on potential mechanisms by which corn oil acts. Substantial progress has been made during the first 2 years of the grant towards achieving each each of these objectives. Studies in unanesthetized, freely-moving rats, contrasting the PK of equal doses of VOCs given orally as a single bolus and by constant intragastric (ig) infusion for up to 6 hours, revealed significantly lower peak blood levels and bioavailability in the ig groups. Blood concentrations of well metabolized VOCs, such as trichloroethylene (TCE) and 1,1-dichloroethylene, were so low that they were hardly detectable at low dosage levels in the ig animals.