The Application Of Physiologically Based Pharmacokinetic Modeling To Determine Route-Specific Contributions To Tissue Dosimetry Of Trihalomethanes In Drinking Water
This project summary describes an improved approach for estimating route-specific exposures and tissue doses for trihalomethane (THM) compounds found in drinking water.
Finished drinking water contains numerous contaminants, including drinking water disinfection byproducts (DBPs). Animal studies are often conducted via the oral route, and the understanding of their relevance to humans is complicated because of the uncertainties in human exposure assessments for DBPs. Volatile contaminants, including some DBPs, in drinking water may enter the human body across the skin, through the lungs and through oral consumption. This study was undertaken to estimate the total exposure of humans to the trihalomethane DBPs through the dermal, inhalation and oral routes. The results for volatile compounds demonstrate that additional exposure through inhalation may represent a quantitatively important exposure route.
Finished drinking water contains numerous contaminants, including drinking water disinfection byproducts (DBPs). Animal studies are often conducted via the oral route, and the understanding of their relevance to humans is complicated because of the uncertainties in human exposure assessments for DBPs. Volatile contaminants, including some DBPs, in drinking water may enter the human body across the skin, through the lungs and through oral consumption. This study was undertaken to estimate the total exposure of humans to the trihalomethane DBPs through the dermal, inhalation and oral routes. The results for volatile compounds demonstrate that additional exposure through inhalation may represent a quantitatively important exposure route.
Impact/Purpose
To have an improved approach for estimating route-specific exposures and tissue does for THM compounds found in drinking water.
Status
Several manuscripts describing these findings in the EPA’s 2006 report will be prepared and published in the open, peer-reviewed literature.
Citation
U.S. EPA. The Application Of Physiologically Based Pharmacokinetic Modeling To Determine Route-Specific Contributions To Tissue Dosimetry Of Trihalomethanes In Drinking Water. 2008.
History/Chronology
| Date | Description |
|---|---|
| Aug 2002 | A letter peer review of the report, The Feasibility of Performing Cumulative Risk Assessments for Mixtures of Disinfection By-Products in Drinking Water (EPA/600/R-03/051) was conducted by Eastern Research Group. |
| Jun 2005 | An independent panel review of the report, Drinking Water Exposures and Internal Doses of Trihalomethanes in Humans (EPA/600/R-06/087), was conducted by Versar, Inc., in Cincinnati, Ohio. |
| Sep 2008 | EPA releases the summary report, The Application of Physiologically Based Pharmacokinetic Modeling to Determine Route-Specific Contributions to Tissue Dosimetry of Trihalomethanes in Drinking Water. |
Related Link(s)
- U.S. EPA (Environmental Protection Agency). 2006b. Stage 2 Disinfectants and Disinfection Byproducts Rule; Final Rule. Federal Register, 71(2):388-493.
- The Feasibility Of Performing Cumulative Risk Assessments For Mixtures Of Disinfection By-Products (DBPs) In Drinking Water
- Use Of Physiologically Based Pharmacokinetic (PBPK) Models To Quantify The Impact Of Human Age And Interindividual Differences In Physiology And Biochemistry Pertinent To Risk (Final Report)