2017 Progress Report: Residential Exposure of Young Children to SVOCs

EPA Grant Number: R835642
Title: Residential Exposure of Young Children to SVOCs
Investigators: Stapleton, Heather M. , 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, 2016 through August 31,2017
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 the ages of 24-48 months;  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 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, fluorotelomer alcohols, PAHs, and brominated flame retardants in 50 passive air samplers that were deployed during the study.  As of November 2017, we have the following biospecimen data available: serum PFC levels (in the children and their mothers), and urinary metabolite measurements for a suite of phenolics and phthalates provided by the laboratory of Dr. Antonia Calafat at the Centers for Disease Control & Prevention (CDC) in Atlanta, GA. My laboratory analyzed the pooled urine samples for metabolites of organophosphate esters (e.g. plasticizers and flame retardant chemicals) and those data are now available.   In total, we currently have exposure measurements (serum and urine) for 34 different SVOCs in urine and serum. In addition to the biospecimens, we have collected samples of house dust, surface wipes and product wipes from each home.  We have also collected ancillary data on the child’s behavior and home characteristics using an investigator initiated survey. Dust samples have all been sieved and weighed after collection, and have now been analyzed for flame retardants, phthalates, several types of PFCs, PCBs, pesticides, and PAHs.  We are in the process of analyzing the samples collected from the residential furniture (polyurethane foam) for flame retardants and will soon conduct analyses to determine associations between applications in furniture with ambient levels in the home (e.g., air/dust) and in children’s urine and serum.   
  3. Analytical Method Development: Dr. Lee Ferguson’s laboratory (co-investigator) analyzed a set of 10 paired house dust and handwipe samples using non-targeted high-resolution mass spectrometry techniques to identify common SVOCs present in these 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 handwipe and dust samples collected from the children’s homes. Over 10,000 chemicals were present in most of the dust samples, and a few dozen chemicals were detected in paired samples of dust and handwipes, including the pesticides fipronil and imidacloprid, organophosphates such as triphenyl phosphate and tris butoxyethyl phosphate, and a suite of surfactants used in laundry detergents, shampoos, etc.   These results highlight the utility of using non-targeted analyses to increase our understanding of individual exposures.  We are now in the process of running the house dust extracts from TESIE through this non-targeted workflow to identify a broader range of chemicals that are present in the homes of these children.  These data will be used to examine mixtures and patterns of co-exposure in the home to better understand links with product use and health outcomes.
  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.  To date we have conducted two pilot studies to explore the utility of using silicone wristbands to measure exposure to organophosphate flame retardants (OPFRs), and polybrominated diphenyl ethers (PBDEs).  In the first pilot study, we recruited 40 adult volunteers and asked them to wear a pre-cleaned wristband for five days.  During those five 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 (Hammel et al. 2016). In the second pilot study, we recruited 30 adult volunteers and asked them to wear a pre-cleaned wristband for five days.  On the fifth day, we collected the wristband and collected a serum sample for analysis of PBDEs.  Our results demonstrated there were significant and positive correlations between PBDEs on the wristbands and PBDEs in the participants' serum.  This latter study is now being written up for publication. Given these findings, we asked some of the child participants in our study to wear a pre-cleaned wristband for five days, and were able to collect 68 samples that will be analyzed as part of this project.
  5. Preliminary Data to Date: Levels of exposure for many of the SVOCs appear to be higher in the TESIE cohort compared to similarly aged children measured in the NHANES study. Analyses are ongoing, but some of these differences in exposure (e.g. phthalates and chlorphenols) are significantly associated with lower socioeconomic status.  As part of our preliminary analyses we have additionally conducted analyses to examine the patterns of co-exposures in these children. What’s interesting from these preliminary analyses is the amount of correlation observed among different classes of chemicals.  By analyzing these patterns in more detail, we hope to determine if particular patterns are associated with product use or behavior, and whether these patterns might be associated with several health outcomes (e.g., asthma, BMI).

Future Activities:

Currently we are focusing a majority of our efforts on completing 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 March 2018 and continuing with the non-targeted analyses through 2018.  Our first manuscripts from this cohort (the TESIE cohort) are in draft and will be submitted within the next few months.  We currently have three draft manuscripts, and more analyses planned for 2018 that should result in additional manuscripts and presentations throughout the next year.

References:

Hammel, S., Hoffman, K., Lorenzo, A., and Stapleton, H.M.   Linking Consumer Products to Flame Retardant Levels in Indoor House Dust. Presented at the annual Society of Toxicology & Environmental Chemistry (SETAC) meeting in Salt Lake City Utah, November 2015.

Vogler, B., Stapleton, H.M., Ferguson, P.L. Non-targeted analysis to assess human exposure to semi volatile organic contaminants in the indoor environment. Presented at the annual meeting of the American Society of Mass Spectrometry, June 2015.

Hammel, S., Hoffman, K., Lorenzo, A., and Stapleton, H.M.  Investigating Associations Between Flame Retardant Application in Televisions and Furniture with Indoor House Dust Levels. Presented at the annual meeting of the International Society of Exposure Science (ISES) meeting in Utrecht, Netherlands, October 2016.

Stapleton, H.M., Volger, B., Ferguson, P.L.  Targeted and Non-Targeted Approaches to Measuring SVOC Exposure Using Handwipes and Indoor Dust.  Presented at the annual meeting of the International Society of Exposure Science (ISES) meeting in Utrecht, Netherlands, October 2016.

Hammel, S.C., Hoffman, K., Lorenzo, A.M., Frenchmeyer, M., Flaherty, B., Phillips, A.L., Chen, A., Webster, T.F., and Stapleton, H.M. Assessing Children's Exposure to Organophosphate Flame Retardants using Passive Air Samples from the Home Environment. Presented at the International Symposium on Flame Retardants (BFR) meeting in York, UK, May 2017.

Hammel, S.C., Hoffman, K., Phillips, A.L., Lorenzo, A.M., Frenchmeyer, M., Flaherty, B., Chen, A., Webster, T.F., and Stapleton, H.M. Children's Exposure to Organophosphate Esters: Socioeconomic Factors & Associations with BMI. Presented at the International Society of Exposure Science (ISES) Annual Conference in Research Triangle Park, North Carolina, October 2017.

Hammel, S.C., Hoffman, K., Phillips, A.L., Stapleton, H.M. Measuring Exposure to Brominated Flame Retardants using Silicone Wristbands. Presented at the International Symposium on Halogenated Persistent Organic Pollutants (Dioxin) in Vancouver, British Columbia, August 2017

Phillips, A. L., Hammel, S. C., Hoffman, K., Lorenzo, A. M., Webster, T. F., Stapleton, H. M. Investigating Exposure to Organophosphate Flame Retardants in the Home Environment. Presented at the annual International Society of Exposure Science (ISES) meeting in Research Triangle Park, North Carolina, October 2017.

Phillips, A. L., Hammel, S. C., Hoffman, K., Lorenzo, A. M., Stapleton, H. M. Assessing Children’s Exposure to Emerging Flame Retardants in North Carolina. Presented at the International Symposium on Halogenated Persistent Organic Pollutants in Vancouver, Canada, August 2017.

Hammel, S., Hoffman, K., Webster, T.F., Anderson, K., and Stapleton, H.M. 2016. Measuring Personal Exposure to Organophosphate Flame Retardants using Silicone Wristbands and Hand Wipes. Environ. Sci. Technol., 50(8): 4483-4491.

Hammel, S., Hoffman, K., Lorenzo, A.M., Chen, A., Phillips, A.L., Butt, C.M., Sosa, J.A., Webster, T.F., Stapleton, H.M. 2017.  Associations Between Flame Retardant Applications in Furniture Foam, House Dust levels, and Resident’s Serum Levels. Environ. Internat., 107:181-189.


Journal Articles on this Report : 2 Displayed | Download in RIS Format

Other project views: All 6 publications 2 publications in selected types All 2 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)
  • Abstract from PubMed
  • Abstract: ACS-Abstract
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  • Other: ACS-Correction Link
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  • Journal Article Hammel, S., Hoffman, K., Lorenzo, A.M., Chen, A., Phillips, A.L., Butt, C.M., Sosa, J.A., Webster, T.F., Stapleton, H.M. 2017. Associations Between Flame Retardant Applications in Furniture Foam, House Dust levels, and Resident’s Serum Levels. Environ. Internat., 107:181-189. R835642 (2017)
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    Supplemental Keywords:

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

    Relevant Websites:

    Toddlers’ Exposure to SVOCs in the Indoor Environment Exit  Exit

    Progress and Final Reports:

    Original Abstract
  • 2015 Progress Report
  • 2016 Progress Report