Notice of objection filed by the Sierra Legal Defense Fund is filing this notice of objection on behalf of the David Suzuki Foundation, Environmental Defence, and the Canadian Environmental Law Association - Annex

February 14, 2006

To Whom It May Concern:

My name is Heather Stapleton, assistant professor of environmental chemistry within the Nicholas School of the Environment and Earth Sciences at Duke University (Durham, NC, USA). For the past seven years I have been investigating the fate, transport and metabolism of brominated flame retardants, and specifically, polybrominated diphenyl ethers (PBDEs), in the environment. In 2003 I received my Ph.D. from the University of Maryland based on a dissertation which examined the uptake and metabolism of PBDEs in fish. Currently I have more than a dozen peer-reviewed papers published on PBDEs with two more currently in review with leading environmental scientific journals. Given this background, I consider myself to be one of the leading experts on PBDE fate and transport in the environment.

With this letter I would like to give you a brief overview of some of the more pressing issues regarding the use of PBDEs, and specifically the issues surrounding the fate of the commercial flame retardant mixture known as Decabromodiphenyl Ether, or DecaBDE. These issues include the bioaccumulation and breakdown potential of the primary component of this mixture, BDE 209. Here are a few of the key points:

  1. Human accumulation of BDE 209
  2. Bioaccumulation of BDE 209 in food webs
  3. Potential for debromination of BDE 209 in the environment

Human Accumulation of BDE 209: BDE 209 has been detected in human tissues (breast milk and serum) in several different studies (1 -3) suggesting it can accumulate in people and is bioavailable, contrary to industrial claims. Due to the fact that house dust has been found to contain some of the most concentrated levels of BDE 209 ever measured, there is some concern that children may be receiving elevated exposure to BDE 209 that is greater than adults. In fact, the only study to examine BDE 209 in children found that BDE 209 was present in serum and at levels that were two orders of magnitude greater than levels measured in adults (3). Thus, there may be concern about children's exposure to DecaBDE in indoor environments.

Bioaccumulation of BDE 209 in Food Webs: Generally speaking, the terms bioaccumulation and biomagnifications indicate that the concentration of a chemical is higher in the animal than it is in their food sources, or in the cases of aquatic environments, higher than the concentration found in the water. Recent studies have detected BDE 209 in a variety of fish, rodent, bird and mammal species, suggesting it is bioaccumulative (4-8). However, it is often difficult to estimate the bioaccumulation potential unless the prey items or food sources have been measured for BDE 209 as well. One study conducted on the food web of Lake Winnipeg in Canada has found evidence to suggest significant bioaccumulation of BDE 209 does occur (9). In this study, the authors calculated biomagnification factors (BMF) for several predator/prey species that had been measured for BDE 209. A BMF is defined as the concentration of a chemical in a predator divided by the concentration of a chemical in its food source/prey. The calculated BMFs for several fish species in Lake Winnipeg ranged from <1 up to 34. This suggests, for example, that some fish had levels of BDE 209 in their tissues that were 34 times greater than the levels in their known food sources, implying bioaccumulation. Furthermore, BDE 209 has been detected and measured in wildlife at levels as high as 12,200 ppb (5) and in some cases it is the primary PBDE congener present in wildlife tissues (4,6). Furthermore, the levels measured in wildlife (bears, foxes, birds, etc.) suggest that accumulation of BDE 209 is occurring at greater rates in terrestrial environments relative to aquatic environments (4,6). Based on this evidence, BDE 209 is believed to be bioaccumulative.

Due to very low water solubility, exact measurements of bioconcentration factors (BCFs) have been difficult to measure/estimate because they rely upon measuring BDE 209 in aqueous systems. However, the estimated Log Kow, values for BDE 209 range from 6.3 to 9.7 (European Commission, 2002; European Chemicals Bureau, 2004) which does classify this compound as bioaccumulative according to the Organisation for Economic Co-operation and Development (OECD) guidelines, which states that in the absence of BCF measurements, a substance is bioaccumulative when the logarithm of its octano-water partition coefficient is equal to or greater than 5.

Potential for Debromination of BDE 209 in the Environment: An additional concern regarding the use and fate of decaBDE is the potential for this compound to breakdown via a mechanism known as debromination. Debromination of BDE 209 indicates that the congener is successively losing bromine atoms from the molecule, creating a smaller, more persistent, more bioaccumulative, and potentially a more toxic compound. Studies have indicated that PBDE congeners with 4 to 7 bromine atoms have greater rates of accumulation, larger BMF values and longer half-lives in tissues that the fully brominated (10 bromine atoms) BDE 209 congener (10-12). Due to the high use and distribution, environmental debromination of BDE 209 may be of concern and lead to greater exposure to lower brominated PBDE congeners. In laboratory studies debromination of BDE 209 has been found to occur from both exposure to UV light and sunlight (13-1 5), by bacteria (16,17) and by endogenous metabolism in fish (18,19). The potential for photolytic debromination and exposure to lower brominated congeners in people is of real concern given the abundance of BDE 209 measured and detected in house dust. Furthermore, BDE 209 is found at relatively large abundance in biosolids and sewage sludge (20-23) which are often land applied as a recycling strategy and receive significant sunlight exposure.

The extent of debromination varies depending on the mechanism involved, and in the case of photolysis, the intensity of the light. Photolytic studies using UV lamps have shown that BDE 209 can debrominate down to tri, tetra-, penta- and hexaBDE congeners (13-15). The extent to which this compound will break down under environmentally relevant conditions is difficult to assess. In one of my own research studies we investigated the debromination potential of BDE 209 in house dust following exposure to natural sunlight. BDE 209 debrominated with a half-life of approximately 200 hours and formation of PBDE congeners with 7 to 9 bromine atoms was observed. This study is currently in review with the journal Environmental Science & Technology. In a fish exposure study we examined the capability of carp to debrominate BDE 209 via metabolism. Following exposure, carp were observed to accumulate one pentaBDE, three hexaBDE, two heptaBDE and one octaBDE congeners as a result of debromination, although the concentrations of these less brominated congeners represented about 1% of the BDE 209 exposure (18). The ability of other species to debrominate BDE 209 is unknown. Exposure studies using rats have found that BDE 209 is metabolized via a combination of debromination and oxidative pathways leading to accumulation of hydroxylated (OH-BDEs) and methoxylated (MeO-BDE) congeners which are also of toxicological concern (24,25).

Given these issues, I would support a ban on the use of the flame retardant mixture known as decaBDE if suitable alternatives can be found. While I acknowledge and appreciate the need for flame retardant chemicals in our products, I think it is also important to reduce exposure to potentially bioaccumulative and toxic chemicals. This is particularly important for reducing exposure to children who are in sensitive developmental stages. With the high levels of BDE 209 measured in indoor environments (i.e. indoor air and dust), children's exposure to this chemical may be significantly higher than most adults. If there are any further questions regarding the statements written herein I can be reached at the contact information below. I am also willing to testify before a board of review on this issue if need be.

Thank you,
Heather Stapleton

Heather M. Stapleton
Assistant Professor
Duke University
Nicholas School of the Environment & Earth Sciences
LSRC, Box 90328
Durham, NC 27708
Phone: (919) 613-8717
Email :

References Cited

14 Feb. 07

David Suzuki Foundation
606, 251 Bank St.
Ottawa, ON K2P 1X3

Science based view on DecaBDE

As I understand the Canadian government has announced their intention to ban PentaBDE and OctaBDE, as EU has. The EU decision was based on some extensive environmental and health risk assessments. I fully agree with the action taken by EU. Despite rather extensive data regarding DecaBDE, no action was taken to regulate the use of DecaBDE at that time. I like to point out a few scientific facts that must be considered by the Canadian government when approaching the question if DecaBDE meets the criteria for "virtual elimination", i.e. persistance, bioacuumulation, and toxicity.

First I like to discuss DecaBDE as the perbrominated diphenyl ether 2,2',3,3',4,4',5,5',6,6'-decaBDE (BDE-209) since the major species in the DecaBDE product is this particular compound. Still it has to be acknowledged that the DecaBDE product contains minor amounts of nonaBDE and traces of octaBDE congeners.

Several scientific peer reviewed articles have shown long range transport of BDE- 209 to geographical areas far away from DecaBDE production sites and use. Even though BDE-209 is readily undergoing photolysis leading to lower brominated diphenyl ethers and to polybrominated dibenzofurans ("dioxins") and reductive reactions to lower brominated diphenyl ethers, BDE-209 is stable enough to undergo long-range transport. The extensive distribution of BDE-209 in the environment has lead to its identification in a very large number of wildlife species and in humans around the world.

The kinetics of BDE-209 is interesting and different from most other environmental pollutants I am aware of. BDE-209 has a short half life in humans, rats and grey seal. In contrast, the very high concentrations determined in some birds of prey are showing a very different behavior in these birds. Most recently birds of prey sampled in China has shown BDE-209 concentrations above 10,000 ppb (to compare with typical North Amarican human levels of 10-100 ppb and European concentrations of 1-10). Aquatic wildlife seems to contain low concentrations of BDE-209. It is evident that BDE-209 is bioaccumulating in terrestrial birds of prey (e.g. Peregrine falcons, Buzzard and Kestrels). Some occasionally high levels of BDE-209, e.g. in humans, are related to recent exposure to DecaBDE. It is still notable that the human levels may be several hundred ppb.

In mammals, including humans, and in fish data show formation of lower brominated diphenyl ethers as a result of BDE-209 metabolism. Most likely a number of other hitherto non-identified hydroxylated metabolites are also formed. Indications of their presence have been published. BDE-209 is undergoing microbial debromination to lower brominated congeners, shown to be persistent, bioaccumulative, and toxic.

Data showing the neurodevelopmental health effects are intriguing and must be taken seriously. Since BDE-209 is forming lower brominated diphenyl ethers the health effects of these PBDEs must be considered. The environment and health risk assessments for PentaBDE and OctaBDE become important documents for this assessment.

DecaBDE (BDE-209) is fulfilling, to the best of my understanding, the criteria of a persistent organic pollutant (POP) (according to the Stockholm convention). My conclusion is that BDE-209 (DecaBDE) needs to be regulated. If it is not done we will have to expect environmental effects to be observed in wildlife with the highest exposure, and possibly in humans with high exposure.

As far as I understand there are alternatives for DecaBDE but I am not going into any further discussion on that matter.

I have not included any references to the appropriate scientific articles above. This can of course be done if there is a request for this. Most likely these articles are included in any up-to-date review of the literature.

I regard this issue of such importance that I am willing to testify at a board of review hearing regarding the POP characteristics of DecaBDE (BDE-209), if I am asked to do so.

Yours sincerely

Åke Bergman
Professor, Ph.D.
Chair of in Environmental Chemistry
A short CV follows on the next few pages

Åke Bergman Curriculum vitae

Name: Bergman, Bengt Ake Lennart (born 1950)
Affiliation: Stockholm University, Department of Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
Telephone: +46-8-163997 (+46-8-163914) or +46-70-644 3861 (mobile phone);
Fax: +46-8-163997;

Education/Academic Training, Degrees and Academic Positions


Research orientation

My present research activities are best seen as presented at our website ( In breif, my research projects in the field of organic environmental chemistry include i: synthesis of standard and test compounds of environmental concern, including metabolites of these compounds and radiolabelled substances; ii: development of analytical methods for and analysis of organic substances in environmental samples (primarily in biota); iii: exposure assessments in humans and wildlife; iv: metabolism studies (kinetics) of environmental pollutants; v: development of a new operational concept of persistency; and vi: contributions to risk assessment of chemicals.

International Committee/Board member

National CommitteeIBoard member

Stockholm University CommitteeIBoard member

Other activities

Reviewer of scientific articles for

Professional Associations (International and National Societies)


Teacher of undergraduate courses

Degrees completed under my supervision

Opponent for doctoral degree (Respondent names given below)

Doctoral degree committees

Publications (please see under my name)
Up till now I have published approximately 200 original scientific articles in peer reviewed international journals and approx. 100 peer reviewed extended abstracts (4-6 pages) for presentations at international symposia, preferentially the Dioxin symposium series. I have published an additional number of short abstracts (1 page or less) for presentations at national and international symposia. The latter have not been listed among the "Publications". Book chapters, popular scientific publications, compendium for teaching, scientific policy documents and debate articles have also been written by me. Part of several newspaper, radio and television interviews and/or discussions.

Invited speaker and session organizer
List available upon request.

Research grants

# The status of the Unit of Environmental Chemistry was changed to Department of Environmental Chemistry in September, 1994

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