2016 Progress Report: Residential Exposure of Young Children to SVOCs

EPA Grant Number: R835642
Title: Residential Exposure of Young Children to SVOCs
Investigators: Stapleton, Heather , Ferguson, P. Lee , Webster, Thomas F.
Institution: Duke University , Boston University
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: Safer Chemicals , Human Health , Health

Objective:

The goals of this project are to:

  1. Characterize SVOC sources in products by collecting surface wipes from consumer products in the home that may be potential sources of SVOCs (and other chemical additives) to the indoor environment (e.g., furniture, vinyl flooring, electronics, insulation);
  2. Characterize and quantify residential exposure of young children to SVOCs using targeted and non-targeted methods on hand wipe samples, and determine how closely these measurements correlate with levels measured in paired samples of serum, urine, indoor air, and house dust from 50 children between 24-48 months of age; 
  3. Identify sources of variability in hand wipe measurements such as hand washing and lotions;
  4. Examine the patterns of co-exposure to multiple SVOCs (an important issue in the assessment of chemical mixtures); and
  5. Compare our empirical results for SVOCs with predictions from indoor models.

Progress Summary:

  1. Participant Recruitment: We have focused a majority of our effort on completing recruitment for this study.  Our original target recruitment was 50 families; however, we increased our target recruitment to 200 families leveraging support from an ongoing NIH funded study that was interested in measuring exposure and health outcomes in a similar cohort (young children). All recruitment and collection of samples are now completed.
  2. Sample Analyses: Extraction and analyses of samples is ongoing. We have extracted and analyzed a suite of organophosphate flame retardants, phthalates, pesticides, and brominated flame retardants in 50 passive air samplers that were deployed during the study. Aliquots of the serum and urine samples have been shipped to an analytical laboratory at the Centers for Disease Control and Prevention to quantify urinary metabolites of phthalates and phenolics and serum levels of perfluoroalkyl compounds. 
  3. Analytical Method Development: Effort has been dedicated to improving detection limits and testing analyte recovery (QA/QC procedures) for a list of 70 targeted SVOCs that we will measure in our samples.  Method development for the non-targeted analyses also has been ongoing, and we have applied the new methods to a set of 10 paired hand wipe and house dust samples. These 10 paired samples were collected from adults, and are being used to optimize the parameters and conditions that will be used for the non-targeted analysis of hand wipe and dust samples collected from the children’s homes. Results of the non-targeted analyses of these samples provided some very interesting data. Over 30,000 chemicals were present in most of the dust samples, and a few dozen chemicals were detected in paired samples of dust and hand wipes, including the pesticides fipronil and imidacloprid, organophosphates such as triphenyl phosphate and tris butoxyethyl phosphate, and a suite of surfactants used in laundry detergents and shampoos. These results highlight the utility of using non-targeted analyses to increase our understanding of individual exposures. This work is currently being written up for publication.
  4. Pilot Study:  Recent studies have also demonstrated the utility of using silicone wristbands in measuring exposure to airborne contaminants. Given the focus of this project, we hypothesized that silicone wristbands might also provide an improved measure of exposure to the targeted chemicals in this study.  We therefore conducted a pilot study to explore the utility of using silicone wristbands to measure exposure to organophosphate flame retardants (OPFRs). To do this, we recruited 40 adult volunteers and asked them to wear a pre-cleaned wristband for 5 days. During those 5 days, three first-morning urine samples were collected and pooled for analysis of OPFR metabolites. Analysis of the data revealed that the mass of OPFRs accumulating on the wristbands were significantly correlated with the concentration of urinary metabolites. Given these findings, we asked some of the child participants in our study to wear a pre-cleaned wristband for 5 days, and were able to collect 68 samples that will be analyzed as part of this project.

Future Activities:

Currently, we are focusing all of our efforts on the analyses of the remaining samples collected through this project (e.g., air, dust, hand wipes, product wipes, urine, and serum). We anticipate completing the sample analyses by December 2017 and continuing with the non-targeted analyses through 2018. Modeling aspects will likely begin in the spring of 2017. 


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

Other project views: All 8 publications 4 publications in selected types All 4 journal articles
Type Citation Project Document Sources
Journal Article Hammel SC, Hoffman K, Webster TF, Anderson KA, Stapleton HM. Measuring personal exposure to organophosphate flame retardants using silicone wristbands and hand wipes. Environmental Science & Technology 2016;50(8):4483-4491. R835642 (2015)
R835642 (2016)
R835642 (2017)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Abstract: ACS-Abstract
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  • Other: ACS-Correction Link
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  • Supplemental Keywords:

    Children’s exposure, SVOCs, indoor environment, wristbands, hand wipes, flame retardants, product wipes

    Progress and Final Reports:

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