2016 Progress Report: Tracking Semivolatile Organic Compounds Indoors: Merging Models and Field Sampling to Access Concentrations, Emissions, and Exposures

EPA Grant Number: R835641
Title: Tracking Semivolatile Organic Compounds Indoors: Merging Models and Field Sampling to Access Concentrations, Emissions, and Exposures
Investigators: Bennett, Deborah H. , Shin, Hyeong-Moo , Young, Thomas M
Institution: University of California - Davis
EPA Project Officer: Carleton, James N
Project Period: September 1, 2014 through August 31, 2017 (Extended to August 31, 2018)
Project Period Covered by this Report: September 1, 2015 through August 31,2016
Project Amount: $900,000
RFA: New Methods in 21st Century Exposure Science (2013) RFA Text |  Recipients Lists
Research Category: Human Health , Safer Chemicals , Health

Objective:

The goals of this project are to: (1) measure concentrations of a broad spectrum of target and non-target semivolatile organic compounds (SVOCs) 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.

Progress Summary:

1. Selection of target compounds: A total of 133 organic chemicals were selected that were either frequently detected in dust based on literature data or had multiple listings in the Consumer Product Chemical Profiles database (CPCPdb) of the U.S. EPA. The selected chemicals are spanning a broad range of the chemical space (polarity, volatility, speciation, functional groups), and from each different chemical class, indicator substances were selected.  

2. Participant recruitment: We recruited about 28 participants who were planning to replace their couches, a major source of flame retardants, in the home. This will allow us to determine how much flame retardants in dust from home is reduced over the time course of enrollment (19 months) when people get a new couch or replace the foam in their couch.

3. Dust collection: We started collection of longitudinal dust samples from 28 participant homes. To date, 20 homes have replaced their couches, and of these homes 16 homes have completed their 6-month follow-up dust collection, and 7 have completed their 12-month follow-up dust collection. In addition, we have collected 24 dust samples from a case-control autism study (CHARGE), 10 dust samples from a cross-over trial asthma study (AIRE), and 6 dust samples from convenience households.

4. Analytical method development: The sample preparation and analytical methods for the measurement of targeted and non-targeted chemicals were finalized and validated during the project period. Fifty-six of the selected chemicals were primarily liquid chromatography-mass spectrometry (LC-MS) amenable, while 77 were primarily gas chromatography-mass spectrometry (GC-MS) amenable.

5. Dermal exposure study: To test the role of passive uptake in adults, we evaluated skin loading of SVOCs by collecting wipe samples from 13 adults. We collected three sequential wipe samples from foreheads—expected to provide an estimate of passive air to skin transfer. The data on total squalene, squalene oxidation products, and sapienic acid also offer insight into how deep in the skin we extract chemicals when using sequential wipes.

6. Indoor exposure modeling: We developed a screening-level exposure assessment method that integrates exposure from all plausible exposure pathways as a result of indoor residential use of cleaning products. The results from this study are published in Indoor Air.     

Future Activities:

  1. Modeling Work – Refine and evaluate a multi-compartment indoor fate, transport, and exposure model with field measurements. Develop a method to reconstruct exposure to SVOCs indoors using indoor dust levels. Compare surface-air partitioning relationships among different regression analyses to find more reliable relationships for application to the indoor fate and transport model. Prepare drafts for publications in peer-reviewed journals.
  2. Dermal Work – Finalize analysis and prepare draft paper for publication.
  3. Field Work – Continue collection of longitudinal dust samples from participants who replaced their couch and analyze changes over time.
  4. Laboratory Work – Continue statistical analysis of non-targeted samples. Prepare draft papers for publication in peer-reviewed journals.
  5. Modeling, Field and Laboratory Work – Determine the sources of compounds in the homes that would be needed to assess the measured concentrations in the dust.


Journal Articles on this Report : 1 Displayed | Download in RIS Format

Other project views: All 7 publications 1 publications in selected types All 1 journal articles
Type Citation Project Document Sources
Journal Article Shin H-M, McKone TE, Bennett DH. Model framework for integrating multiple exposure pathways to chemicals in household cleaning products. Indoor Air 2017;27(4):829-839. R835641 (2016)
R835641 (2017)
  • Abstract from PubMed
  • Abstract: Wiley-Abstract
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  • Supplemental Keywords:

    indoor environment, measurement methods, modeling, organics, indoor air

    Progress and Final Reports:

    Original Abstract
  • 2015 Progress Report
  • 2017 Progress Report
  • Final