Emerging Contaminants -
           Polybrominated  Diphenyl Ethers (PBDE)and
                              Polybrominated Biphenyls  (PBB)
                                                                        April 2008
                                                                                   FACT SHEET
At a Glance
   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
   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
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
* 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
       Solid Waste and
       Emergency Response

EPA 505-F-07-007
      April 2008

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
    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
                    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).
 CAS Numbers
   PBDE (Penta-, Octa-, an
OctaBDE - 32536-52-0
    PBB (Hexa-, Octa-, an
OctaBB - 27858-07-7
 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 25C)
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)
 Log Kow
5.7 to 8.27
5.53 to 9.1
 Henry's Law Constant (atm-m3/mol)
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.

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
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).

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.
: ATSDR. 2007. Minimal Risk Levels for
   Hazardous Substances.
: 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.
: 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.
U.S.  Department of Health and Human Services
(DHHS). 2005. Report on Carcinogens, 11th
Edition - Substance Profile on Polybrominated
Biphenyls (PBB).
U.S.  Occupational Safety and Health
Administration (OSHA). 2007.
U.S.  EPA Office of Pollution Prevention and
Toxics. 2007a. Polybrominated Diphenylethers.
EPA Integrated Risk Information System.
2007b. www.epa.gov/iris
Washington State Department of Labor and
Industries (WDLI). 2007. Workplace Exposure
to PBDEs.
World Health Organization International Agency
for Research on Cancer (IARC). 2007.  Agents
Reviewed by the IARC Monographs: Volumes 1-
96 (Alphabetical Order).
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.