Emerging Contaminants -
Polybrominated Diphenyl Ethers (PBDE)and
Polybrominated Biphenyls (PBB)
April 2008
FACT SHEET
At a Glance
Introduction
PBDE and PBB are groups of man-
made chemicals that serve as flame
retardants for electrical equipment,
electronic devices, furniture, textiles,
and other household products.
PBBs have been banned in the United
States since the early 1970s, but
PBDEs continue to be widely used.
PBDEs and PBBs are structurally
similar and exhibit low volatility.
Some PBDEs and PBBs may act as
endocrine disrupters in humans and
other animals. Exposure in rats and
mice caused neuro-developmental
toxicity, and other symptoms.
DecaBDE homolog has been
classified as "possible human
carcinogen".
PBBs have been classified as
"possibly carcinogenic to humans".
The American Conference of
Governmental and Industrial
Hygienists (ACGIH) has established
workplace environmental exposure
levels (WEEL) for PBDEs and PBBs.
EPA has developed oral reference
doses (RfD) for decaBDE, octaBDE
and pentaBDE.
Treatment methods have not been
developed for any environmental
media; potential treatment methods
being evaluated at the laboratory scale
include debromination using zero
valent iron (ZVI) and enhanced
biodegradation using microbial
species.
An "emerging contaminant" is a chemical or material that is characterized
by a perceived, potential, or real threat to human health or the
environment or a lack of published health standards. A contaminant may
also be "emerging" because a new source or a new pathway to humans
has been discovered or a new detection method or treatment technology
has been developed (DoD 2007). This fact sheet, developed by the U.S.
Environmental Protection Agency (EPA) Federal Facilities Restoration
and Reuse Office (FFRRO), provides a brief summary for polybrominated
diphenyl ethers (PBDE) and polybrominated biphenyls (PBB), including
physical and chemical properties; environmental and health impacts;
existing federal and state guidelines; detection and treatment methods;
and additional sources of information.
PBB has been banned in the United States (US) since 1973 when it was
accidentally mixed into animal feed exposing 9 million people to
contaminated dairy products, eggs, and meat (De Wit 2002; DHHS
2005). In contrast, PBDEs have been in widespread use in the US since
the 1970s; however, there is growing concern about their persistence in
the environment and their tendency to bioaccumulate in the food chain
(EPA 2007a). This fact sheet provides basic information on PBDEs and
PBBs to site managers and other field personnel who may encounter
these contaminants at a cleanup site.
What are PBDE and PBB?
* PBDE and PBB are brominated flame retardant (BFR) chemicals that
are used in a wide variety of products, including furniture, upholstery,
electrical equipment, electronic devices, textiles, and other household
products (EPA 2007a; WDLI 2007; ATSDR 2004).
* At high temperatures, PBDEs and PBBs release bromine radicals
that reduce both the rate of combustion and dispersion of fire (De Wit
2002).
* PBDEs exist as mixtures of distinct chemicals called congeners, each
with unique molecular structures. The PBDE congeners may differ in
the total number and/or position of bromine atoms attached to the
ether molecule. Congeners with same number of bromine atoms are
known as homologs (De Wit 2002; ATSDR 2004).
* Three PBDE homologs are commercially available, including
pentaBDE (PeBDE), octaBDE (OBDE), and decaBDE (DeBDE) (De
Wit 2002).
United States
Environmental Protection
Agency
Solid Waste and
Emergency Response
(5106P)
1
EPA 505-F-07-007
April 2008
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What are PBDE and PBB? (continued)
PBBs also exist as mixtures of congeners. They
were produced as three primary homologs:
hexabromobiphenyl, octabromobiphenyl, and
decabromobiphenyl (ATSDR 2004; DHHS
2005).
There are no known natural sources of PBDE
and PBB (ATSDR 2004).
Both PBDE and PBB are structurally similar to
polychlorinated biphenyls (PCB). Both PBDE
and PBB are fat-soluble and hydrophobic (De
Wit 2002; Hooper and McDonald 2000).
What are the environmental impacts of PBDE and PBB?
Homologs with the highest numbers of bromine
atoms tend to exhibit the lowest volatilities (De
Wit 2002; DHHS 2005).
Even though PBDEs and PBBs are relatively
stable, they are susceptible to photolytic
debromination when they are exposed to
ultraviolet light (De Wit 2002; DHHS 2005).
PBDEs and PBBs have been detected in air,
sediments, surface water, fish, and other marine
animals (Streets and others 2006).
PBDEs may enter the environment through
emissions from manufacturing processes,
volatilization from various products that contain
PBDEs, recycling wastes, and leaching from
waste disposal sites (Streets and others 2006).
As of 2004, PBBs have been found at nine NPL
sites, although PBDEs have not been found at
any of the current or deleted NPL sites. This
may imply that PBDEs are widely used in
commercial products and therefore may be less
prevalent at hazardous waste sites (ATSDR
2004).
Exhibit 1: Physical and Chemical Properties of PBDE and PBB
(ATSDR 2004; De Wit 2002)
Lower brominated congeners of PBDE tend to
bioaccumulate more than higher brominated
congeners and are more persistent in the
environment (De Wit 2002).
Higher brominated congeners of PBDE tend to
bind to sediment or soil particles more than
lower brominated congeners (De Wit 2002).
PBBs bind strongly to soil or sediment particles,
which reduces their mobility on the ground but
increases their mobility in the atmosphere,
where they are attached to airborne particulate
matter (ATSDR 2004).
Property
CAS Numbers
PBDE (Penta-, Octa-, an
Deca-BDE)
PentaDBE-32534-81-9
OctaBDE - 32536-52-0
DecaBDE-1163-19-5
PBB (Hexa-, Octa-, an
Deca-BB)
HexaBB-36355-01-8
OctaBB - 27858-07-7
DecaBB-13654-09-6
Physical description (physical state at
room temperature)
Pale yellow liquid or white powder
White solid
Molecular weight (g/mol)
564 to 959.2 (DecaBDE)
627 to 943
Water solubility (ug/L at 25°C)
1
3 to 30
Boiling point (°C)
>300 to >400
Not applicable
Melting point ( C)
85 to 306
72 to 386
Vapor pressure at 25 C (mm Hg)
2.2x10"7to9x10"10
5.2x10"'
Log Kow
5.7 to 8.27
5.53 to 9.1
Henry's Law Constant (atm-m3/mol)
7.5x10'8to1.2x10'5
1.38 x10'D to 5.7x10"
Notes: g/mol - gram per mole; |jg/L - micrograms per liter; °C - degrees Celsius; mm Hg - millimeters of mercury; K™,- Octanol-Water
Partition Coefficient.
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What are the health effects of PBDE and PBB?
Studies on animals and human beings have
shown that some PBBs and PBDEs can act as
endocrine system disrupters and also tend to
deposit in human adipose tissue (McDonald
2002; DHHS 2005; Birnbaum and Staskal 2004;
He and others 2006; ATSDR 2004).
A study has indicated that octaBDE may be a
potential teratogen (He and others 2006).
According to EPA's Integrated Risk Assessment
System (IRIS), decaBDE has been classified as
a "possible human carcinogen." This
classification is still under review (EPA 2007b).
The International Agency for Research on
Cancer (IARC) classified PBBs as "possibly
carcinogenic to humans" (IARC 2007). EPA has
not classified PBBs for carcinogenicity (EPA
2007a).
Studies on mice and rats have shown that
exposure to PBDEs and PBBs cause neuro-
developmental toxicity, weight loss, toxicity to
the kidney, thyroid, and liver, and dermal
disorders (Birnbaum and Staskal 2004; De Wit
2002; ATSDR 2004).
Are there any existing federal and state guidelines and health standards for PBDE
and PBB?
EPA continues to evaluate and assess the risks
posed by PBDEs and PBBs. No federal
standards or guidelines have been set for
PBDEs and PBBs (ATSDR 2004; EPA 2007a).
EPA has established the following oral RfDs for
PBDEs: 1 x 10~2 mg/kg-day for decaBDE
homolog; 3 x 10~3 mg/kg-day for octaBDE
homolog; and, 2 x 10"3 mg/kg-day for pentaBDE
homolog (EPA 2007b).
EPA has issued a Significant New Use Rule
(SNUR) to phase out pentaBDE and octaBDE.
According to this rule, no new manufacture or
import of these two homologs is allowed after
January 1, 2005, without a 90-day notification to
EPA for evaluation (EPA 2007a).
The ACGIH has developed a WEEL of 5
milligrams per cubic meter (mg/m3) for
decaBDE. Air monitoring may be required if
dust levels of penta and octaBDE exceed 5
mg/m3 (WDLI 2007).
The Agency for Toxic Substances and Disease
Registry (ATSDR) has established a minimal
risk level (MRL) of 0.01 mg/kg-day for acute (1
to 14 days) oral exposure to PBBs and an MRL
of 10 mg/kg/day for intermediate (14 to 364
days) oral exposure to decaBDE (ATSDR 2007).
Cal/EPA proposed a No Significant Risk Level of
0.02 micrograms per day (ug/day) for PBBs (Cal
EPA 2007).
The U.S. Occupational Safety and Health
Administration (OSHA) has not established
occupational exposure limits for PBDEs or PBBs
(ATSDR 2004; OSHA 2007).
What detection and site characterization methods are available for PBDE and PBB?
Analytical methods used for PBDE include Gas
Chromatography (GC)-Mass Spectrometry (MS)
for air, sewage, fish, and animal tissues;
GC/Electron-Capture Detector (ECD) for water
and sediment samples; GC/High Resolution MS
(HRMS) for fish tissue; and Liquid
Chromatography (LC)/GC-MS-Flame lonization
Detector (FID) for sediments (ATSDR 2004).
Analytical methods for PBBs include GC-ECD
for commercial samples, soil, plant tissue,
sediment, fish, dairy, and animal feed; High
Resolution-GC-HRMS for fish samples; GC-
FID/ECD for soil; and LC-GC-MS/FID for
sediment (ATSDR 2004).
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What technologies are being used to treat PBDE and PBB?
Research is being conducted at laboratory scale
on potential treatment methods for media
contaminated with PBDEs and PBBs.
A laboratory study investigated the degradation
of a mixture of decaBDE and octaBDE using
anaerobic bacteria (He and others 2006).
Another laboratory study investigated zero
valent iron (ZVI) as a treatment method for
decaBDE. Secondary treatment using cationic
surfactants may be required to increase the
availability of PBDE molecules for reactions with
ZVI (Keum and Li 2005).
Where can I find more information about PBDE and PBB?
* Agency for Toxic Substances and Disease
Registry (ATSDR). 2004. Toxicological Profile
for Polybrominated Diphenyl Ethers and
Polybrominated Biphenyls.
www.atsdr.cdc.gov/toxprofiles/tp68.html
«:« ATSDR. 2007. Minimal Risk Levels for
Hazardous Substances.
www.atsdr.cdc.gov/mrls/index.htmltfbookmarkQ2
«:« Birnbaum, L. S. and D. F. Staskal. 2004.
Brominated Flame Retardants: Cause for
Concern? Environmental Health Perspectives,
Vol. 112, No. 1, pp. 9 to 13.
* California Environmental Protection Agency (Cal
EPA) Office of Environmental Health and
Hazard Assessment. 2007.
www.oehha.ca.gov/risk/ChemicalDB/start.asp
«:« De Wit, C. A. 2002. An Overview of Brominated
Flame Retardants in the Environment.
Chemosphere, Vol. 46, pp. 583 to 624.
* He, J., K. R. Robrock, and L. Alvarez-Cohen.
2006. Microbial Reductive Debromination of
PBDEs. Environmental Science & Technology,
Vol. 40, pp. 4429 to 4434.
«:« Hooper, K., and T.A. McDonald. 2000. The
PBDEs: An Emerging Environmental Challenge
and Another Reason for Breast-Milk Monitoring
Programs. Environmental Health Perspectives,
Vol. 108(5), pp. 387 to 392.
«:« Keum, Y-S., and Q. X. Li. 2005. Reductive
Debromination of PBDEs by Zerovalent Iron.
Environmental Science & Technology, Vol. 39,
pp. 2280 to 2286.
«:« McDonald, T. A. 2002. A Perspective on the
Potential Health Risks of PBDEs.
Chemosphere, Vol. 46, pp. 745 to 755.
Contact Information
Streets, S. S., S. A. Henderson, A. D. Stoner, D.
L. Carlson, M. F. Simcik, and D. L. Swackhamer.
2006. Partitioning and Bioaccumulation of
PBDEs and PCBs in Lake Michigan.
Environmental Science & Technology, Vol. 40,
pp. 7263 to 7269.
U.S. Department of Defense (DoD). 2007.
www.denix.osd.mil/denix/Public/Library/MERIT/
merit.html
U.S. Department of Health and Human Services
(DHHS). 2005. Report on Carcinogens, 11th
Edition - Substance Profile on Polybrominated
Biphenyls (PBB).
http://ntp.niehs.nih.gov/ntp/roc/eleventh/profiles/
U.S. Occupational Safety and Health
Administration (OSHA). 2007.
http://osha.gov/SLTC/pel/standards.html
U.S. EPA Office of Pollution Prevention and
Toxics. 2007a. Polybrominated Diphenylethers.
www.epa.gov/oppt/pbde/
EPA Integrated Risk Information System.
2007b. www.epa.gov/iris
Washington State Department of Labor and
Industries (WDLI). 2007. Workplace Exposure
to PBDEs.
www.lni.wa.gov/Safetv/Topics/AtoZ/polybrom/de
fault.asp
World Health Organization International Agency
for Research on Cancer (IARC). 2007. Agents
Reviewed by the IARC Monographs: Volumes 1-
96 (Alphabetical Order).
http://monographs.iarc.fr/ENG/Classification/List
agentsalphorder.pdf
If you have any questions or comments on this fact sheet, please contact: Mary Cooke, FFRRO, by phone at
(703) 603-8712 or by e-mail at cooke.maryt@epa.gov.
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