Superfund Research Program

Assessment of Human VOC Exposure Near Superfund Sites

Project Leader: Karla Thrall
Grant Number: P42ES010338
Funding Period: 2000-2006

Project-Specific Links

Final Progress Reports

Year:   2005 

Research Problem: Neurotoxic chemical contaminants found at Superfund sites have the potential to pollute water supplies and expose humans while showering, bathing, washing dishes, doing laundry and drinking water. Little is known, however, about the magnitude of exposure that may occur by each of the various exposure routes (inhalation, ingestion, dermal absorption).  Dr. Thrall and her research team are addressing this problem by using a novel breath analysis system that allows them to determine the amount of volatile organic chemical that has entered the body by any route of exposure and are developing mathematical models to describe the absorption, distribution, metabolism, and excretion of these chemicals. By interpreting the exhaled breath data with their mathematical models, they can estimate the amount of contaminant that has entered particular tissues and thereby provide data that will allow scientists to more accurately assess the toxicological risks that are involved.

 

Accomplishments: Efforts have continued to focus on development of a preliminary mathematical model to describe the absorption, tissue distribution, metabolism and elimination of 1,2-diethylbenzene in rats.  A liquid chromatographic method was developed and applied to the analysis of blood samples collected from rats receiving either an intraperitoneal injection of 1,2-diethylbenzene or pulmonary exposure by inhalation.  A manuscript describing the development of the analytical method and analysis of in vivo blood, urine and tissue samples is currently under minor revision prior to publication.

 

Significance: The research underway is designed to provide an understanding of the influence of route of exposure on the total body burden and internal target tissue dosimetry of commonly encountered Superfund contaminants.  Since this research will extend existing physiologically based pharmacokinetic models to describe brain dosimetry following exposures, this effort will enhance the ability to accurately extrapolate animal studies to relevant human exposures and improve hazard and risk assessments.  The development of exposure assessment data in human volunteers based on realistic exposures will enable relevant health risk assessment extrapolations to occur.