Exposure and Health Effects of PBDEs
Update in progress: Stay tuned!
Our principal focus is the investigation of human exposure to PBDEs in the indoor environment and their health effects. We have broadened this work to include other semivolatile organic compounds (SVOCs), including new and alternative flame retardants and perfluoroalkyl substances (PFAS).
Polybrominated diphenyl ethers (PBDEs)
PBDEs are a class of compounds commonly used as fire retardants in furniture containing polyurethane foam (PUF) and consumer products such as televisions. As shown by their generic chemical structure below, PBDEs are structurally related to their better known cousins: PCBs, polybrominated biphenyls (PBBs), and polychorinated dioxins/dibenzofurans. These compounds are persistent organic pollutants (POPs) and semivolatile organic compounds (SVOCs). Human body burdens and environmental concentrations of PBDEs increased for several decades (with recent indications of declines) and vary geographically, with the highest values reported in the USA. Major questions include impacts on human health and the environment and major routes of human exposure.
Exposure to PBDEs
PBDEs are persistent and bioaccumulative, suggesting exposure via diet, particularly animal products. Given their use in consumer products, it is very likely that the indoor environment also causes exposure. We found associations between PBDE concentrations in people and i) consumption of dairy products and meat, ii) house dust sampled from participant’s homes (Wu et al 2005, 2007); see the figure below. The latter finding--in first time mothers from the Greater Boston area--is particularly important because of the very large uncertainty in adult exposure to dust. It supports the hypothesis that exposure to PBDEs in dust is an important route of exposure.
People are exposed to PBDEs via dust and diet. See: Wu N, Herrmann T, Paepke O, Tickner J, Hale R, Harvey E, La Guardia M, McClean MD, Webster TF. Human exposure to PBDEs: Associations of PBDE body burdens with food consumption and house dust concentrations. Environ Sci Technol 2007; 41(5): 1584-1589. Web release date: 17 Jan 2007. Abstract and full text (for ES&T subscribers): doi=10.1021/es0620282]. See also the accompanying ES&T news report by Kellyn Betts.
The correlation between concentrations of PBDEs in people and in dust cannot, by itself, distinguish between direct exposure to dust (via incidental ingestion or dermal exposure) and inhalation, if the concentrations in air and dust are correlated. Exposure estimates by ourselves (Webster et al 2005) and others suggest that ingestion/dermal exposure to dust is more important than inhalation of indoor air. However, most such calculations rely on indoor air measurements made in rooms using passive air monitors, a method that should underestimate personal exposure. We therefore carried out a second study comparing personal air measurements with room air measurements, using active air pumps (Allen et al., 2007). We found higher concentrations of PBDEs in 'personal air' (sampled near the breathing zone) than in rooms, particularly for decaBDE which is bound to particulate. This is indicative of a personal dust cloud, also known as the Pigpen effect.
We all have our little dust clouds. Read about it in our article: Allen JG, McClean MD, Stapleton HM, Nelson JW, Webster TF. Personal exposure to polybrominated diphenyl ethers (PBDEs) in residential indoor air. Environ Sci Technol 2007; 41(13): 4574-4579. Abstract and full text (for ES&T subscribers): doi=10.1021/es0703170.
Sources of PBDEs in the Indoor Environment
PBDEs in indoor air and dust are thought to originate with consumer products such as foam-containing furniture and electronics. However, most earlier research including our own (Wu et al 2007, Allen et al 2007) finds no association between indoor PBDE concentrations and counts of foam-containing furniture and electronics. This could be caused by non-differential exposure misclassification (e.g. large differences in PBDE content between otherwise similar objects), producing a bias toward the null. To deal with this problem, we have used X-ray fluorescence (XRF), providing an easy and quick surrogate measure of the bromine content of household products. This work was published in Environmental Science and Technology in 2008.
Read the news story in Environmental Science &Technology about our work with XRF, as presented at BFR07.
"This handheld X-ray fluorescence analyzer allows Joseph Allen of Boston University to detect in seconds the presence of bromine in household products such as televisions."
photo by M. Kenda
Dust sampling: What is to be done?
Dust appears to be an important source of exposure for PBDEs. But there are several important questions about sampling dust:
- Is it better to examine the concentration of PBDEs in dust or the amount of PBDEs per area of floor?
- How much do PBDE dust concentrations change over time in homes? Is a single snap-shot good enough?
- Do PBDE concentrations in dust vary between rooms within the same home?
- It's easy to collect vacuum cleaner bags from homes. How well does this match dust collected by more standardized methods?
- Do the PBDE concentrations in dust correlate with those in indoor air?
If you'd like to know more about these issues, read our recent paper: Allen JG, McClean MD, Stapleton HM, Webster TF. Critical Factors in Assessing Exposure to PBDEs via House Dust. Environ Intern 2008; 34: 1085-1091. [Online 5 May 2008]. Abstract and full text (for EI subscribers): doi: 10.1016/j.envint.2008.03.006.
New and alternative BFRs: Deja vu all over again?
Penta and octa have been banned in the US but is the problem solved? There is still enormous amounts of this stuff in people's homes as well as being thrown out. In addition, we've been finding new and alternative brominated flame retardents in dust. Pictured at left is a recently identified component of Firemaster 550, a brominated form of the phthalate DEHP. For more information on FM550, look here.
DBDPE: Another alternative BFR in house dust
Decabromodiphenyl ethane (DBDPE) is another new flame retardant we found in house dust, in collaboration with Heather Stapleton. This and other work was recently profiled in ES&T by Kellyn Betts.
How do PBDEs get from products into dust? Do they off-gas or is the plastic breaking down into little bits? To find out, read our new paper and the accompanying news story "CSI-style tools offer clues about flame retardants in dust."
TDCPP (chlorinated tris): A replacement for pentaBDE
Wonder what is being used in polyurethane foam as a flame retardant now that production of the Penta form of PBDE has been banned? Firemaster 550 is one alternative (above). Another is TDCPP, also known as chlorinated tris. This compound, along with its more famous cousin (brominated tris), were used for a while in kids' pajamas before being removed about 30 years ago. See our new paper.
News & Awards (For details, look here)
- We hosted BFR 2011: The Twelfth Annual Workshop on Brominated and Other Flame Retardant on 6-7 June 2011 at Boston University. Sic transit gloria mundi.
- 13 September 2010: Tom Webster gave the opening plenary, "Indoor Exposure to PBDEs and PFCs: You’re Not Just What You Eat" at Dioxin 2010, the 30th International Symposium on Halogenated Persistent Organic Pollutants (San Antonio, Texas 12-17 September 2010). Our group had a large number of other papers as well on PBDEs, alternative flame retardants and (PFCs).
- 13 August 2010: Alicia Fraser defends her dissertation "Assessing Exposure to Polybrominated Diphenyl Ethers and Polyfluroinated Compounds from Diet and the Indoor Environment"
- October 2009. News article by Naomi Lubick in Environmental Health Perspectives ''PBDEs in Diet: Meat Fat a Leading Source" on our recent PBDE and diet paper, Fraser et al 2009.
- 18 August 2009: News article by Kellyn Betts, Discontinued pajama flame retardant detected in baby products and house dust, discusses our new paper on TDCPP (chlorinated tris).
- 17 July 2009: News article in Wired about our new paper on diet as a source of exposure to PBDEs.
- 18 March 2009: News article by Kellyn Betts, CSI-style tools offer clues about flame retardants in dust, in ES&T discusses our new paper on the use of scanning electron microscopes and other "CSI" tools to investigate PBDEs in dust.
- 3 December 2008: News article by Kellyn Betts in ES&T discusses decabromodiphenyl ethane (DBDPE), another new flame retardant we found in house dust.
- 23 July 2008: See our paper on alternative brominated flame retardants in dust, including components of Firemaster 550, the replacement for penta in Environmental Science and Technology. See also the accompanying story by Kellyn Betts. For more information on FM550, look here.
- July 2008: Our PBDE work was featured in the Summer 2008 edition of Bostonia magazine, Art Jahnke's article "Trouble at Home."
- 1 May 2008: Work by our PBDE group heavily featured in a news story in today's Environmental Health Perspectives.
- 18 April 2008: Our PBDE work featured on Nature Network Boston.
- 27 March 2008: Three new papers on exposure to PBDEs are in press: on PBDEs in handwipes, measuring PBDEs in dust, linking PBDEs in dust to household products via XRF. See publications below.
- 19 March 2008: News story about our work with Heather Stapleton on measuring PBDEs on handwipes.
- 6 March 2008: Paper on PBDEs by doctoral student Nerissa Wu one of the most cited papers published in ES&T in 2007.
- 10 December 2007: Doctoral student Joe Allen defended his dissertation!
- 13 June 2007: News story "Finding PBDEs in couches and TVs" in ES&T
- 24 May 2007: What do PBDEs have to do with the the cartoon character Pigpen?
- 27 April 2007: Doctoral student Joseph Allen wins award at BFR 2007
- 17 January 2007: News story by Kellyn Betts, "The risk of PBDEs in dust" in ES&T
- Makey CM, McClean MD, Braverman LE, Pearce EN, He X-M, Sjödin A, Weinberg JM, Webster TF. Polybrominated Diphenyl Ether Exposure and Thyroid Function Tests in North American Adults. Environ Health Perspect 2015 [accepted 11 September 2015] DOI:10.1289/ehp.1509755
- Makey C, McClean M, Sjödin, A Weinberg J, Carignan C, Webster TF. Temporal variability of PBDE serum concentrations over one-year. Environ Sci Technol 2014; 48:1462-9 [accepted 10 November 2014]. DOI: 10.1021/es5026118
- Keller AS, Raju NP, Webster TF, Stapleton HM. Flame Retardant Applications in Camping Tents and Potential Exposure. Environ. Sci. Technol. Lett. 2014; 1(2):152–155 [7 January 2014] DOI: 10.1021/ez400185y
- Stapleton HM, Misenheimer J, Hoffman K, Webster, TF. Flame Retardant Associations Between Children’s Handwipes and House Dust. Chemosphere 2014; 116: 54–60. DOI: 10.1016/j.chemosphere.2013.12.100
- Carignan CC, Heiger-Bernays W, McClean MD, Roberts SC, Stapleton HM, Sjödin A, Webster TF. Flame Retardant Exposure among Collegiate U.S. Gymnasts. Environ Sci Technol 2013; 47:13848–13856. DOI: 10.1021/es4037868 [accepted 6 November 2013].
- Watkins DJ, McClean MD, Fraser AJ, Weinberg J, Stapleton HM, Webster TF. Associations between PBDEs in office air, dust, and surface wipes. Environment International 2013; 59:124–132 [accepted 2 June 2013]. DOI: 10.1016/j.envint.2013.06.001
- Webster TF, Stapleton HM, McClean MD. Exposure to PBDEs in the Indoor Environment. Fire Technology [accepted 7 March 2013]. doi: 10.1007/s10694-013-0334-9
- Stapleton HM, Eagle S, Sjödin A, Webster TF. Serum PBDEs in a North Carolina Toddler Cohort: Associations with Hand Wipes, House Dust and Socioeconomic Variables. Environ Health Perspect 2012. [Online 23 May 2012]. http://dx.doi.org/10.1289/ehp.1104802.
- Watkins D, McClean M, Fraser A, Weinberg J, Stapleton HM, Sjodin A, Webster TF. Impact of Dust from Multiple Microenvironments and Diet on PentaBDE Body Burden. Environ Sci Technol 2012; 46: 1192–1200 [online 5 December 2011]. DOI: 10.1021/es203314e.
- Cooper EM, Covaci A, van Nuijs ALN, Webster TF, Stapleton HM. Analysis of the flame retardant metabolites bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and diphenyl phosphate (DPP) in urine using liquid chromatography–tandem mass spectrometry. Analytical and Bioanalytical Chemistry 2011; 401:2123–2132. [Published online 11 August 2011] DOI: 10.1007/s00216-011-5294-7
- Watkins DJ, McClean MD, Fraser AJ, Weinberg J, Stapleton HM, Sjödin A, Webster TF. Exposure to PBDEs in the Office Environment: Evaluating the Relationships Between Dust, Handwipes, and Serum. Environ Health Perspect 2011; 119:1247-1252. [Online 30 June 2011]. doi:10.1289/ehp.1003271.
- Stapleton HM, Klosterhaus S, Keller A, Ferguson PL, van Bergen S, Cooper E, Webster TF, Blum A. Identification of Flame Retardants in Polyurethane Foam Collected from Baby Products. Environ Sci Technol 2011. [Accepted 18 May 2011]. doi: 10.1021/es2007462.
- DiGangi J, Blum A, Bergman Å, de Wit CA, Lucas D, Mortimer D, Schecter A, Scheringer M, Shaw SD, Webster TF. San Antonio Statement on Brominated and Chlorinated Flame Retardant. Environ Health Perspect. 2010; 118:A516-A518. [Online 28 October 2010] The full text is freely available doi:10.1289/ehp.1003089.
- Harrad S, Abdallah M, de Wit C, Östman C, Bergh C, Covaci A, Darnerud PO, de Boer J, Leonards P, Diamond M, Huber S, Mandalakis M, Haug L, Thomsen C, Webster T. Indoor contamination with hexachlorocyclododecanes, polybrominated diphenyl ethers, and perfluoroalkyl compounds: An important exposure pathway? Environ Sci Technol 2010; 4:3221–3231 [Accepted 31 March 2010]. Abstract and full text (for ES&T subscribers): DOI: 10.1021/es903476t.
- Stapleton HM, Klosterhaus S, Eagle S, Fuh J, Meeker JD, Blum A, Webster TF. Detection of Organophosphate Flame Retardants in Furniture Foam and U.S. House Dust. Environ Sci Technol 2009; 43:7490–7495. [Online 13 August 2009]. Abstract and full text (for ES&T subscribers): DOI: 10.1021/es901401.
- Fraser AJ, Webster TF, McClean MD. Diet contributes significantly to the body burden of PBDEs in the general U.S. population. Environ Health Perspect 2009; 117:1520-1525. [Online 18 June 2009]. The full text is freely available doi:10.1289/ehp.0900817.
- Webster TF, Harrad S, Millette JR, Holbrook RD, Davis JM, Stapleton HM, Allen JG, McClean, MichaeI MD, Ibarra C, Abdallah M, Covaci A. Identifying transfer mechanisms and sources of decabromodiphenyl ether (BDE 209) in indoor environments using environmental forensic microscopy. Environ Sci Technol 2009; 43(9): 3067–3072. [Online 18 March]. Abstract and full text (for ES&T subscribers): doi: 10.1021/es803139w. The text is freely available as via NIH at NIHMS103471.
- Wu N, McClean MD, Brown P, Aschengrau A, Webster TF. Participant Experiences in a Breastmilk Biomonitoring Study: A qualitative assessment. Environmental Health; 2009, 8:4. [Online 18 February 2009]. The full text is freely available doi:10.1186/1476-069X-8-4.
- Stapleton HM, Kelly SM, Allen JG, Watkins DJ, Heiger-Bernays WJ, Mcclean MD, Webster TF,Konstantinov A, Klosterhaus S. Response to Comment on "Alternate and New Brominated Flame Retardants in US House Dust." Environ Sci Technol 2008; 42: 9455-6. [Online 14 November 2008]. Full text (for ES&T subscribers): doi: 10.1021/es802619.
- Stapleton HM, Allen JG, Kelly S, Konstantinov A, Klosterhaus S, Watkins D, Mcclean MD, Webster TF. Alternate and New Brominated Flame Retardants Detected in US House Dust. Environ Sci Technol 2008; 42 (18), 6910–6916. [Online 23 July 2008]. Abstract and full text (for ES&T subscribers): doi: 10.1021/es702964a.
- Allen JG, McClean MD, Stapleton HM, Webster TF. Critical Factors in Assessing Exposure to PBDEs via House Dust. Environ Intern 2008; 34: 1085-1091. [Online 5 May 2008]. Abstract and full text (for EI subscribers): doi: 10.1016/j.envint.2008.03.006.
- Allen JG, McClean MD, Stapleton HM, Webster TF. Linking PBDEs in House Dust to Consumer Products using X-ray Fluorescence (XRF). Environ Sci Technol 2008; 42 (11): 4222–4228. [Online April 30, 2008]. Abstract and full text (for ES&T subscribers): doi: 10.1021/es702964a.
- Stapleton HM, Kelly SM, Allen JG, McClean MD, Webster TF. Measurement of Polybrominated Diphenyl Ethers on Hand Wipes: Estimating Exposure from Hand to Mouth Contact. Environ Sci Technol 42(9): 3329-34. [Web release date: 19 March 2008]. DOI: 10.1021/es7029625. See also the accompanying ES&T news story by Kellyn Betts.
- Allen JG, McClean MD, Stapleton HM, Nelson JW, Webster TF. Personal exposure to polybrominated diphenyl ethers (PBDEs) in residential indoor air. Environ Sci Technol 2007; 41(13): 4574-4579. Web release date: 24 May 2007. Abstract and full text (for ES&T subscribers): doi=10.1021/es0703170.
- Wu N, Herrmann T, Paepke O, Tickner J, Hale R, Harvey E, La Guardia M, McClean MD, Webster TF. Human exposure to PBDEs: Associations of PBDE body burdens with food consumption and house dust concentrations. Environ Sci Technol 2007; 41(5): 1584-1589. Web release date: 17 Jan 2007. Abstract and full text (for ES&T subscribers): doi=10.1021/es0620282. See also the accompanying ES&T news report by Kellyn Betts.
- Allen JG, McClean MD, Stapleton HM, Webster TF. PBDEs in dust: between- and within-home variation linked to XRF characterization of consumer products. Organohalogen Compounds 2007; 69:1002-1004.
- Allen JG, McClean MD, Stapleton HM, Nelson JW, Sanchez G, Fraser AJ, Webster TF. Personal and indoor air exposure to PBDEs in US urban residences. Organohalogen Compounds 2006; 68:2198-2201.
- Webster TF. Pharmacokinetics of POPs: Simple models with different implications for halflives and steady state levels. Organohalogen Compounds 2006; 68:344-347. The full text is freely available here.
- Wu N, Webster T, Herrmann T, Paepke O, Tickner J, Hale R, Harvey E, La Guardia M, Jacobs E. Associations of PBDE Levels in Breast Milk with Diet and Indoor Dust Concentrations. Organohalogen Compounds 2005; 67: 654-657.
- Webster T, Vieira V, Schecter A. Estimating Exposure to PBDE-47 via Air, Food and Dust Using Monte Carlo Methods. Organohalogen Compounds 2005; 67: 505-8. The full text is freely available here,
Links (Collaborators, etc.)
For more information:
email: Dr. Tom Webster