Tracking Semivolatile Organic Compounds Indoors: Merging Models and Field Sampling to Access Concentrations, Emissions, and ExposuresEPA Grant Number: R835641
Title: Tracking Semivolatile Organic Compounds Indoors: Merging Models and Field Sampling to Access Concentrations, Emissions, and Exposures
Investigators: Bennett, Deborah H. , Young, Thomas M , Shin, Hyeong-Moo
Institution: University of California - Davis
EPA Project Officer: Klieforth, Barbara I
Project Period: September 1, 2014 through August 31, 2017 (Extended to August 31, 2018)
Project Amount: $900,000
RFA: New Methods in 21st Century Exposure Science (2013) RFA Text | Recipients Lists
Research Category: Human Health , Safer Chemicals , Health
The goals of this project are to (1) measure concentrations of a broad spectrum of target and non-target semivolatile organic compounds (SOVCs) in indoor dust to estimate emission rates and exposures, (2) refine and evaluate a multi-compartment indoor fate, transport, and exposure model, and (3) evaluate air-to-skin transdermal uptake models.
First, we will develop and utilize liquid and gas chromatography and high resolution (time-of-flight) mass spectrometry to rapidly assess concentrations of a broad spectrum of SVOCs in indoor dust collected from participating homes in a field study. We will estimate emission rates of SVOCs for these homes using inverse modeling applied to SVOC levels in dust. With these emission rates, we will estimate exposures using our indoor exposure model. The robustness of such estimates will be greatly improved by the inclusion of a larger number and greater diversity of chemical constituents. We will also apply factor analysis to look for common source profiles. Second, we will provide a data set to evaluate indoor models by measuring half-lives of penta-brominated diphenyl ethers (BDEs) after removing sources in the study participant homes. We will also update critical model parameters, both by measuring dust loading and dust removal rates from a field study and by evaluating new model process equations and available data in the literature in order to refine our indoor model. Third, we will evaluate air-to-skin transdermal update models by measuring SVOC concentrations in human skin to determine if measured levels are similar to values anticipated by the models.
The overall outcome of this research will be a significantly improved understanding of what chemicals and which pathways result in current exposures to the U.S. populations. The development of new analytical methods using high resolution (HR) mass spectrometric (MS) techniques and analysis of dust samples address the EPA's objective to develop and evaluate methods for rapid measurement of multiple compounds in the indoor environment. The improvements to the indoor exposure model through the development of the evaluation data set, collection of model input data, and evaluation of model processes, including the dermal pathway, address the EPA's objective to advance the scientific basis of exposure predictions.