Sponsor:

National Center for Environmental Assessment, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, Ohio.

Summary of Project:

Report Objectives, Introduction, Table of Contents and Citation

The Final Report.  This report is an appendix the the following EPA report (see Appendix I) (PDF File, 9 MB):

The Feasibility of Performing Cumulative Risk Assessments for Mixtures of Disinfection By-Products in Drinking Water

For more information about the NCEA research program, go to:  http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=56834

Sponsor:

National Center for Environmental Assessment, U.S. Environmental Protection Agency, 26 W. Martin Luther King Drive, Cincinnati, Ohio.

Abstract:

The concentrations of the four commonly-identified trihalomethanes (THM;
chloroform, bromodichloromethane, chlorodibromomethane and bromoform) in U.S.
drinking water systems are regulated as a group. This report develops, applies and
communicates a method to estimate internal exposures to these simultaneouslyexposed
chemicals. Because they are present in water used for drinking, bathing and
other household uses, and because they are highly volatile, this work evaluated the
development of internal doses via the oral, dermal and inhalation routes following
residential exposures. This was accomplished by integrating several data sets that
characterize human activity patterns, water use behavior, household volumes and
ventilation, and THM concentration in drinking water. Physiologically based
pharmacokinetic modeling was used to translate external exposures to internal doses
for the simulated adult male and female and the 6-year-old child. Results indicated that
inhalation exposures predominated and that children developed higher internal doses
(mg/kg body weight) than adults in the same household. This report demonstrates the
technical feasibility of combining stochastic and deterministic models and modeling
approaches with “real-world” concentrations of drinking water contaminants (here,
THMs) to estimate internal doses for risk evaluation and for the examination of
toxicokinetic interactions among mixtures of chemicals.

The Final Report (PDF file, 3.3 MB):

Exposures and Internal Doses of Trihalomethanes in Humans: Multi-Route Contributions from Drinking Water

The citation of this report is:  

Wilkes CR, Kedderis GL, Mason AD, Niang LL, and J Lipscomb. June 2006. U.S. EPA.  Exposures and Internal Doses of Trihalomethanes in Humans: Multi-
Route Contributions from Drinking Water. Office of Research and Development,
National Center for Environmental Assessment, Cincinnati, OH. EPA 600/R-06/087.