Bioaccumulation assessment criteria related to the regulation of fire-retardant chemicals
Petition: No. 262
Issue(s): Human health/environmental health, and toxic substances
Petitioner(s): Mary Lou McDonald
Date Received: 16 July 2008
Summary: The petitioner is concerned that the assessment criteria in the Persistence and Bioaccumulation Regulations do not adequately measure the bioaccumulation effects of certain fire-retardant chemicals, such as decabromodiphenyl ether (decaBDE). The petitioner asks the federal government to modify the regulations to test exposure through water, food, and air. The petitioner also requests that the federal government recommend a ban on decaBDE under the Canadian Environmental Protection Act, 1999, since the petitioner alleges that it has already been demonstrated that decaBDE is persistent, toxic, and bioaccumulative.
July 15, 2008
Auditor General of Canada
240 Sparks Street
Ottawa, ON K1A 0G6
Petition Requesting a Ban of DecaBDE and a Change to the Bioaccumulation Regulations
My name is Mary Lou McDonald, and I have a concern with the final regulations published on July 9, 2008 relating to Polybrominated Diphenyl Ethers (“PBDEs”). July 9, 2008 is two years to the day when my father, Robert C. McDonald, died from ALS, a horrible degenerative disease that takes its victims quickly. Dad fought hard, and one of his steps was to eliminate all toxins from his environment. The reason he did this is because ALS is a condition of “good cells gone bad”: the good cells attack a bad substance then keep on going and attack the body, so the idea is to eliminate all exposure to bad substances. In the end, he was convinced that something in the institutional lift chair that was brought into the house accelerated his decline. Four days before he died, I promised him that I would look into it and try to make a difference. By that time, the disease had taken his speech, but not his inner strength, and his response was to gesture as strongly as he could with his head and eyes that I should do that.
So I started looking into it, and my investigations led to PBDEs. I could not believe the extent to which PBDEs are everywhere, and we don’t even know about them or know that they are all around us in our everyday lives. Like Dad didn’t know that there was anything in his chair. I, like Dad, thought we were safe if we did not eat bad things or expose ourselves to sources of pollution like factories. I did not realize that we are exposed to dangerous chemicals in items around us every day: furniture, rugs, beds, drapes, clothing, and (I emphasize the next ones) our computers, TVs and cars. This realization had two effects.
First, this realization made me angry. I educated myself and read everything I could on PBDEs. I learned that they are used as fire retardants, and that the bromine (a fire retardant) industry is opposed to banning PBDEs, for obvious reasons. However firefighters are joining the fight against PBDEs because too many of them are dying from exposure to the corrosive gas released when PBDEs burn. I learned that there are three commercial mixtures of PBDEs, known and PentaBDE, OctaBDE and DecaBDE. Most jurisdictions are agreed that the first two are toxic and have banned them, and more and more jurisdictions (like Sweden, Maine and Washington) are moving against DecaBDE.
When I looked into the commercial mixture DecaBDE more (also known as BDE-209), I learned that it is made up almost entirely of the chemical known as “small d” decaBDE. It is used to add fire retardant capability to hard plastics, such as those used in the items in our personal space everyday like cars, computers, and TVs. I learned that it debrominates or breaks down when exposed to sunlight into banned chemicals, and that this debromination has even been acknowledged by Environment Canada. Because it is in our TVs, computers and cars, it is being found in alarming concentrations in household and office dust and on car windshields, and small children receive up to 300 times more exposure than adults from household dust and breastmilk. Some studies have described a “personal cloud effect” of DecaBDE, meaning there is more DecaBDE in “personal air” than in general area air. Yet more than 22 million kilograms of DecaBDE are built into consumer products in North America in a year.
I also learned there are inexpensive, alternative ways to retard fire other than using DecaBDE. Substitute substances, design changes and different technologies can all be used, and for no extra cost in most cases, and for a marginal price increase in other cases. For example, hard television enclosures can be made from alternative resins combined with fire retardants other than DecaBDE, and a shift to such other resins would result in only a small increase in the price of low-end televisions.1 For every car component that uses DecaBDE, there is an alternative on the market. The fact that alternatives are available and not expensive did not appease my anger, as you can appreciate.
The second effect of the realization that PBDEs are all around us was to ask what the government is doing about it. So I looked into it and saw that the federal government had proposed regulations on PBDEs on December 16, 2006 and have now published, on July 9, 2008 (as indicated), the final PBDE regulations (the “New Regulations”). I applaud the government for the New Regulations insofar as they ban the first two commercial mixtures of PBDEs, PentaBDE ad OctaBDE.
But the government has not gone far enough because it has not banned DecaBDE. The press release announcing the New Regulations, however, did indicate that Environment Canada is performing “a detailed review of the newly published science on DecaBDE, to determine if there is a need for further controls on the DecaBDE commercial mixture”.2 Environment Canada has reviewed newly published science, (post-2005) on decaBDE and has prepared a draft report. “When finalised, the Report will assist the Minister with his decision on whether to establish a Board of Review, and whether further controls on decaBDE are required.”3
Purpose of the Petition
The purpose of this petition is to ask the Minister of the Environment to take the extra step and recommend banning decaBDE. The reason is that the new science is clearly indicating that decaBDE bioaccumulates in air-breathing organisms. This has been “confirmed unambiguously” with respect to terrestrial top predators, such as the red fox.4 Data obtained from addled eggs of peregrine falcons and other raptors in the United States and China and from polar bears provide supporting evidence for this conclusion, as do numerous other studies.
Which begs the question: If decaBDE bioaccumulates, why was it not caught by the screening for bioaccumulation under the Canadian Environmental Protection Act? I have looked into this question, and the answer is that the criteria set out in the Persistence and Bioaccumulation Regulations (the “Bioaccumulation Regs”) are faulty, because they let some substances fall through the cracks. One such substance is decaBDE. So I also petition the government to change the screening tests in the Bioaccumulation Regs or change the way they are applied so that all substances are caught.
The rest of this document will explain how it is that the Bioaccumulation Regs fall short of the mark and should be changed.
Regulatory Criteria Fail to Detect Bioaccumulation of Some Substances
The government in its Toxic Substances Management Policy – Persistence and Bioaccumulation Criteria5 employs the definition of bioaccumulation as “a general term describing a process by which substances are accumulated by organisms directly from the surrounding media and through consumption of food containing the substances”6
Environment Canada in its web glossary describes bioaccumulation as “substances that are stored in living tissues (including people), and remain for very long periods of time, during which concentrations can reach very high levels. These substances can also be transferred up the food chain.” This transfer up the food chain is also called biomagnification.
The regulatory criteria for determining bioaccumulation as set out in the Bioaccumulation Regs are bioaccumulation factor (“BAF”), bioconcentration factor (“BCF”) and logarithm of the substance's octanol-water partition coefficient (“KOW”). The BAF and BCF both measure the accumulation of the substance from surrounding media, and the BAF also includes the uptake of chemical from food. The KOW is an estimation of a substance’s hydrophobicity or lipophilicity and its tendency to partition into organic and biological matrices from water.
However the Bioaccumulation Regs are “water biased” (my term). The Bioaccumulation Regs define the BAF as: “the ratio of the concentration of a substance in an organism to the concentration in water, based on uptake from the surrounding medium and food”. The BCF is defined as “the ratio of the concentration of a substance in an organism to the concentration in water, based on uptake from the surrounding medium”. The KOW is defined as the ratio of the concentration of a substance in an octanol phase to the concentration of the substance in the water phase of an octanol-water mixture.
The Bioaccumulation Regs outline the endpoint values and processes for determining bioaccumulation in Section 4. The endpoint values for the criteria are:
(a) when its BAF is equal to or greater than 5 000;
(b) if its BAF cannot be determined in accordance with a method referred to in section 5, when its BCF is equal to or greater than 5 000; and
(c) if neither its BAF nor its BCF can be determined in accordance with a method referred to in section 5, when the KOW is equal to or greater than 100,000 (or logarithm10 KOW ³ 5).
The method referred to in section 5 is the generally recognized methods of the Organisation for Economic Co-operation and Development (“OECD”) or of some other similar organisation or, if no such methods exists, in accordance with generally recognized methods within the scientific community and taking into account the intrinsic properties of the substance, the ecosystem under consideration and the conditions in the environment.
What is interesting is that decaBDE meets the log KOW tests set out in the Bioaccumulation Regs. Environment Canada estimates the log KOW for BDE-209 is in the range of 6.27 to 9.97,7 which is greater than the regulated log KOW of decaBDE > 5. This means to me that the testers were of the view that decaBDE did not pass either the BAF or the BCF tests of the Bioaccumulation Regs.
One reason that decaBDE would not have passed either the BAF or the BCF tests of the Bioaccumulation Regs is that these tests are “water-biased”: they are based on the concentrations of chemicals in water, and such water tests don’t work for chemicals like decaBDE. The Bioaccumulation Regs, in comparing the concentration of the substance in the organism to the concentration in water, assume that the concentration in water is relevant vis-à-vis the concentration in the organism. However, the concentration of the substance in the organism may not be related to the concentration of the substance in water, as, for example, is the case for organisms that respire air such as birds and mammals, including humans. As such, the Bioaccumulation Regs fail to detect substances that are taken up from the surrounding media that are not directly based to an aquatic environment (e.g., fish). A chemical property that does reflect bioaccumulation potential for air respiring organisms is the octanol-air partition coefficient (“KOA”).
The literature has indicated that bioaccumulation (in the form of biomagnification) of certain substances is occurring in air-breathing terrestrial and marine organisms by virtue of the high KOA of the substances and low rate of respiratory elimination from air-breathing animals. A summary of one article is below.
“Substances that accumulate to hazardous levels in living organisms pose environmental and human-health risks, which governments seek to reduce or eliminate. Regulatory authorities identify bioaccumulative substances as hydrophobic, fat-soluble chemicals having high octanol-water partition coefficients (KOW) (³ 100,000). Here we show that poorly metabolizable, moderately hydrophobic substances with a KOW between 100 and 100,000, which do not biomagnify (that is, increase in chemical concentrations in organisms with increasing trophic level) in aquatic food webs, can biomagnify to a high degree in food webs containing air-breathing animals (including humans) because of their high octanol-air partition coefficient (KOA) and corresponding low rate of respiratory elimination to air. These low KOW - high KOA chemicals, representing a third of organic chemicals in commercial use, constitute an unidentified class of potentially bioaccumulative substances that require regulatory assessment to prevent possible ecosystem and human-health consequences.”8
A recent review of BCF and BAF assessments for chemicals in aquatic organisms makes the same point that criteria derived only for water-respiring organisms do not adequately measure bioaccumulation in terrestrial beings:
“Bioaccumulation regulations need to consider organisms other than aquatic species for hazard and risk assessment. All current criteria are based on endpoints obtained from aquatic species while many deleterious effects attributable to high levels of bioaccumulation are observed in non-aquatic organisms (e.g., birds, mammals). For chemicals with low KOW but high KOA, aquatic organisms have a greater capacity for elimination of these chemicals than air breathing organisms. Such chemicals have been observed to biomagnify in terrestrial food webs while showing no bioaccumulation in aquatic food webs (Kelly and Gobas 2001, 2003; Czub and McLachlan 2004). In absence of metabolic biotransformation, approximately 40% of commercial chemicals that do not biomagnify in aquatic systems have the potential to biomagnify in terrestrial food webs (Gobas et al. 2003). While some of the aquatic based criteria may be able to indirectly identify bioaccumulative hazards to non-aquatic species, current criteria do not explicitly account for these inherent differences between aquatic and terrestrial organisms.”9
As indicated, decaBDE bioaccumulates in air-breathing organisms. DecaBDE has also been determined to have low water solubility.10 Because DecaBDE bioaccumulates in air-breathing terrestrial organisms and has very low water solubility, bioaccumulation assessments on decaBDE in relation to water are not useful. Bioaccumulation assessments made in relation to water are letting some chemicals fall through the cracks.
The possibility that the criteria set out in the Bioaccumulation Regs may not always prove adequate was recognized in the 1995 document that formed the basis for the criteria, the Toxic Substances Management Policy: Persistence and Bioaccumulation Criteria. The authors, the ad hoc Science Group on Criteria, therein stated: “In the future, with scientific progress in our understanding of persistence of bioaccumulation processes and methodological developments, there may be a need to revise both the criteria and the critical values”.11 Science has progressed to the point where these revisions need to be made.
Request for Tests and Approaches that Better Reflect Bioaccumulation Potential
It is my understanding, although I am by no means a scientist, that various other tests and approaches could be used that might better reflect bioaccumulation potential. Based on the studies presented above, it appears that augmenting the bioaccumulation criteria with the KOA would be beneficial. Testing could occur through exposure through water, diet and air respiration, depending on the type of substance. Also allowing for a less rigid endpoint determination standard might be useful. That is, rather than having a cut-off point of 5 000 for BAF and BCF, perhaps a range could be employed while factoring in other evidence. Bioaccumulation modelling approaches could also be explicitly allowed, as could other modelling approaches that consider bioaccumulation, persistence and toxicity from a more holistic, generalized perspective in the context of risk.
For example, modelling has correctly shown that DecaBDE bioaccumulates. The authors of the article mentioned above who point out that some substances are not caught by current regulatory criteria used modelling to demonstrate the biomagnification of chemicals exhibiting characteristics of low KOW - low KOA, low KOW - high KOA and finally high KOW - high KOA. The article included modelling for PBDE 209, which is the commercial mixture that contains 98 to 99% decaBDE. It found that PBDE 209 was of the “high KOW - high KOA” category, in that it had a log KOW of 9.9 and a log KOA of 13.1. It also found that the biomagnification factor for decaBDE in terrestrial carnivores and humans was 8, which is greater than the recognized biomagnification factor hazard indicator of 1. Based on this model, decaBDE bioaccumulates in humans and terrestrial carnivores.
Based on the above:
- I petition the Ministers of Health and the Environment to recommend a ban on decaBDE under CEPA because it is bioaccumulative, and has already been shown to be persistent and toxic.
If they do not, then I petition them to specifically answer these questions:
- what is their response to the fact that the new science indicates and it has been “confirmed unambiguosly” that decaBDE bioaccumulates in certain top predators;
- what is their response to my point that bioaccumulation tests that are “water-biased” do not adequately test all substances including decaBDE;
- what is their response to the following position: since bioaccumulation tests based on water do not adequately test for bioaccumulation of some substances taken in by air-respiring species (such as decaBDE), and since the BAF and BCF tests as defined in the Bioaccumulation Regs are based on water, then the BAF and BCF tests as set out in the Bioaccumulation Regs can never determine the bioaccumulation potential of certain substances?
- I petition the Ministers of Health and the Environment to recommend a change to the Bioaccumulation Regs to employ additional criteria that recognize uptake of a substance through media other than water and species other than aquatic species; to test through exposure to water, food and air; to employ less strict endpoint values and methods; and to recognize other methods for determining bioaccumulation such as modelling.
If they do not, then I petition them to:
- advise on the steps they will take to ensure that no substances fall through the cracks in bioaccumulation assessments; and
- apply the Bioaccumulation Regs to decaBDE as they are written. The Bioaccumulation Regs state that if neither the BAF nor the BCF of a substance can be determined in accordance with a referenced method, then the test is met when logarithm10 KOW ³ 5. Since it is the case, as indicated in 1(c) above, that the BAF and BCF tests as set out in the Bioaccumulation Regs can never determine the bioaccumulation potential of certain substances, simply by virtue of the fact that the tests are defined in relation to water, then recourse is had, as required by the actual wording of the Bioaccumulation Regs, to the log KOW test. DecaBDE meets the log KOW test.
Thank you for considering this petition. Please help me keep my promise to my Dad: both to honour his memory and also for the sake of all the other Canadians who are exposed to persistent, toxic and bioaccumulative substances like decaBDE in their everyday lives.
[Original signed by Mary Lou McDonald]
Mary Lou McDonald
c/o 2845 Bristol Circle
Oakville, ON L6H 5L7
1 Maine Department of Environment Protection and Maine Centre for Disease Control and Prevention. 2007, Brominated Flame-retardants: Third annual report to the Maine Legislature, January 2007 at 35.
2 Environment Canada New Release, “Government of Canada Bans More Harmful Chemicals More Action Taken Under Chemicals Management Plan , Ottawa, July 11, 2008.
3 Environment Canada, Regulatory Impact Analysis Statement, Ottawa, July 9, 2008.
4 47 Voorspoels, S. et al 2006. Remarkable Findings Concerning PBDEs in the Terrestrial Top-Predator Red Fox (VulpesVulpes). Environ. Sci. Tech. 40. 2937-2943).
5 Environment Canada Toxic Substances Management Policy: Persistence and Bioaccumulation Criteria, June 1995 Ottawa Final Report of the ad hoc Science Group on Criteria p. 13
6 Environment Canada. Toxic Substances Management Policy – Persistence and Bioaccumulation Criteria. (June 1995) at 18.
7 Environment Canada. 2006. Canadian Environmental Protection Act, 1999 Ecological Screening Assessment Report on Polybrominated Diphenyl Ethers (PBDEs). p. 5.
8 B. Kelly et al, ‘Food-Web Specific Biomagnification of Persistent Organic Pollutants’, 317 Science (13 July 2007) 236, at 236.
9 J. Arnot and F. Gobas, ‘A Review of Bioconcentration Factor (BCF) and Bioaccumulation Factor (BAF) Assessments for Organic Chemicals in Aquatic Organisms’, 14 Environ. Rev. (2006), 257, at 292.
10 Per Ola Darnerud, Gunnar S. Eriksen, Torkell Jóhannesson, Poul B. Larsen, and Matti Viluksela. 2001. Polybrominated Diphenyl Ethers: Occurrence, Dietary Exposure, and Toxicology. Environmental Health Perspective Supplement. Vol 109, 49 at 49, 50.
11 Environment Canada Toxic Substances Management Policy: Persistence and Bioaccumulation Criteria, June 1995 Ottawa Final Report of the ad hoc Science Group on Criteria p. 13
11 November 2008
Ms. Mary Lou McDonald
2845 Bristol Circle
Dear Ms. McDonald:
I am pleased to provide Environment Canada’s and Health Canada’s joint response to your Environmental Petition No. 262, to the Commissioner of the Environment and Sustainable Development, requesting a ban on decabromodiphenyl ether (decaBDE) and requesting changes to the Persistence and Bioaccumulation Regulations of the Canadian Environmental Protection Act, 1999. Your petition was received in the Department on July 18.
Please find enclosed a joint response from Environment Canada and Health Canada to questions that fall within the mandates of each of the departments.
I appreciate this opportunity to respond to your petition and trust that you will find this information useful.
[Original signed by Jim Prentice, Minister of the Environment]
The Honourable Jim Prentice, P.C., Q.C., M.P.
|c.c.:||The Honourable Leona Aglukkaq, P.C., M.P.
Mr. Scott Vaughan, Commissioner of the Environment and
11 November 2008
Ms. Mary Lou McDonald
c/o 2845 Bristol Circle
Oakville, Ontario L6H 5L7
Dear Ms. McDonald:
This is in response to your environmental petition No. 262 of July 16, 2008, addressed to the Commissioner of the Environment and Sustainable Development.
In your petition you raised concerns about the use of decabromodiphenyl ether (decaBDE).
Due to the nature of the questions being raised in the petition, Health Canada has collaborated with Environment Canada to prepare a joint response. My colleague, the Honourable John Baird, Minister of the Environment, will be providing you with the Government of Canada response to the petition. This response has been reviewed by my officials, who are in concurrence with its conclusions.
I appreciate your interest in this important matter, and I hope that you will find the information useful.
[Original signed by Leona Aglukkaq, Minister of Health]
|c.c.:||Mr. Scott Vaughan, CESD
The Honourable Jim Prentice, P.C., M.P.
Environment Canada’s and Health Canada’s Response to
Environmental Petition No. 262, pursuant to section 22 of the Auditor General Act, requesting a ban on decabromodiphenyl ether (decaBDE) and requesting changes to the Persistence and Bioaccumulation Regulations of the Canadian Environmental Protection Act, 1999
(a) I petition the Ministers of Health and the Environment to recommend a ban on decaBDE under CEPA because it is bioaccumulative, and has already been shown to be persistent and toxic.
On July 1, 2006, the Government of Canada published its final screening assessment of polybrominated diphenyl ethers (PBDEs) (see reference 1). The human health risk assessment concluded that worst‑case estimates of the exposure of Canadians to PBDEs were much lower than the levels of exposure which caused health effects in laboratory animals. The environmental risk assessment concluded that PBDEs (i.e., tetrabromodiphenyl ether [tetraBDE], pentabromodiphenyl ether [pentaBDE], hexabromodiphenyl ether [hexaBDE], heptabromodiphenyl ether [heptaBDE], octabromodiphenyl ether [octaBDE], nonabromodiphenyl ether [nonaBDE] and decabromodiphenyl ether [decaBDE]), which are found in commercial PentaBDE, OctaBDE and DecaBDE technical formulations, are entering the environment in a quantity or concentration or under conditions that have or may have an immediate or long‑term harmful effect on the environment or its biological diversity. Therefore, PBDEs meet the criteria under paragraph 64(a) of the Canadian Environmental Protection Act, 1999 (CEPA 1999). In addition, it was concluded that all PBDEs assessed met the criteria for persistence, but only tetra- to hexaBDEs met the criteria for bioaccumulation as defined in the Persistence and Bioaccumulation Regulations under CEPA 1999. The analysis also noted that the higher brominated diphenyl ethers, and decaBDE in particular, could accumulate to some degree in biota and debrominate to bioaccumulative and persistent transformation products.
The environmental component of the PBDE screening assessment considered information obtained as of October 2004 (see references 1 and 7). Although information received between November 2004 and October 2005 was reviewed, it was generally not added to the assessment because these studies supported the conclusions of the draft assessment published for public comment in 2004. Since 2004, a large amount of information has been published, notably on the issues of decaBDE bioaccumulation and transformation.
In order to understand the wealth of new information on decaBDE published during and after 2004, Environment Canada has prepared a draft State of Science Report on the Bioaccumulation and Transformation of Decabromodiphenyl Ether that examines the current science respecting the bioaccumulation and transformation of decaBDE in the environment. This report also considers the new data to determine whether these show that the bioaccumulation criteria as identified in the Regulations under CEPA 1999 are met for this substance. The draft Report has recently undergone a peer review by external science experts from international and Canadian governments, academia, non‑governmental environmental groups and industry. It will be published later this fall for a 60‑day public comment period on the CEPA Environmental Registry website (www.ec.gc.ca/CEPARegistry/participation), and a summary will be published in the Canada Gazette publication (http://canadagazette.gc.ca). An announcement respecting its availability for public comment will also occur through the federal government’s Canadian Chemical Substances Portal (www.chemicalsubstanceschimiques.gc.ca/en). During the public comment period, you can review this report and submit any comments you may have respecting its contents. This review will be used to determine whether further controls on the decaBDE commercial mixture are warranted.
The final Polybrominated Diphenyl Ethers Regulations were published in the Canada Gazette, Part II, on July 9, 2008. The purpose of the Regulations is to protect Canada’s environment from the risks associated with PBDEs by preventing their manufacture and restricting their use in Canada, therefore minimizing their releases into the environment. These regulations represent an important first step in the risk management of PBDEs in Canada, with a focus on those PBDEs of greatest concern. To complement the Regulations, several other risk management measures are currently being developed, including: a regulation to address PBDEs in manufactured products, a voluntary approach to minimize releases into the environment from the use of the DecaBDE commercial mixture in Canadian manufacturing operations, a detailed review of recently published science on decaBDE (as noted above), and monitoring Canadians’ exposure to PBDEs and concentrations in the environment. More details are outlined in the revised Risk Management Strategy for PBDEs (www.ec.gc.ca/TOXICS/EN/detail.cfm?par_substanceID=201&par_actn=s1).
If they do not, then I petition them to specifically answer these questions:
a. what is their response to the fact that the new science indicates and it has been “confirmed unambiguously” that decaBDE bioaccumulates in certain top predators;
The draft State of Science Report on the Bioaccumulation and Transformation of Decabromodiphenyl Ether provides a detailed evaluation of decaBDE bioaccumulation for water ‑ and air‑breathing organisms. The evaluation identifies and reviews many studies showing detected concentrations of decaBDE in a wide range of terrestrial and aquatic biota, including top predators. This analysis confirms that decaBDE can accumulate in organisms and echoes your concern that decaBDE may accumulate in wildlife to potentially high concentrations. Elevated levels (e.g., exceeding 100 nanograms per gram [ng/g] lipid) of decaBDE have been measured in the tissues of several top predators, including:
- Birds of prey, especially Kestrels, Sparrowhawks and Owls in China; Buzzards, Peregrine Falcons, Sparrowhawks and Kestrels (tissues and/or eggs) in Europe; and Peregrine Falcon eggs in Greenland (see references 4, 9, 10, 15 and 21).
- Red fox in Belgium (see reference 13).
- Sharks of coastal Florida (see reference 11).
- Marine mammals, such as harbor seals and whitebeaked dolphins (see reference 16).
In addition, research shows that in some species the decaBDE tissue concentrations are increasing rapidly. Based on sampling conducted of Herring Gull (Larus argentatus) eggs from the Great Lakes basin, a mean doubling time for decaBDE concentrations in eggs has been determined to be 2.1 to 3 years (see reference 8). As well, many other studies describe some accumulation in terrestrial organisms, such as polar bears.
It should be noted that studies showing accumulation, even to high levels, may not support that a substance is meeting criteria for bioaccumulation as identified in the Persistence and Bioaccumulation Regulations. This may be because studies do not compare measured decaBDE concentrations in tissues with those determined in the environment and/or consumed food, so these studies do not provide the appropriate numerical evidence to determine whether or not decaBDE may be bioaccumulative as defined under CEPA 1999.
As well, elevated concentrations in biota may reflect localized areas of high decaBDE concentrations. If environmental concentrations are sufficiently high, biota concentrations may also become very high in equilibrium with their surrounding environment and food, although quantified bioaccumulation factors (BAFs), biomagnification factors (BMFs) or bioconcentration factors (BCFs) may be very low. There are now a variety of field studies which estimate BMFs. These are reviewed in the State of Science Report. The Report also describes the results of bioaccumulation and biomagnification modelling for decaBDE with consideration given to the substance’s log n-octanol-water partition coefficient (Kow), log n-octanol-air partition coefficient (Koa), and rates of metabolic transformation shown in the literature for decaBDE.
Based on their study of decaBDE concentrations in the tissues of red fox from Belgium, Voorspoels et al. (see reference 13) are quoted as saying that new science has “confirmed unambiguously” that decaBDE bioaccumulates in top predators. In their study, decaBDE was detected in less than half of the tissue samples, with concentrations (ng/g lipid) that ranged from less than 9.1 to 760 for liver, from less than 3.9 to 290 in muscle, and from less than 3.7 to 200 for adipose tissue. However, in a follow‑up paper by Voorspoels et al. (see reference 14), decaBDE was not detected in the main prey species of red fox. For this study, whether biomagnification or bioaccumulation was taking place could not be established. However, the fact that decaBDE is accumulating in wildlife, sometimes rapidly and sometimes to high levels, is problematic and a potential ecological concern. Further information on studies examining the bioaccumulation potential of decaBDE will be available in the State of Science Report on the Bioaccumulation and Transformation of Decabromodiphenyl Ether.
b. what is their response to my point that bioaccumulation tests that are “water-biased” do not adequately test all substances including decaBDE;
The available science indicates that decaBDE is a very hydrophobic substance. For example, an industry study determined that the limit of water solubility for decaBDE was less than 0.1 micrograms per litre (µg/L) at 25 degrees Celsius (see reference 12). The available predicted estimates (using Quantitative Structure Activity Models or QSARs) for decaBDE indicate that its solubility may be in the range of 2.84 x 10-8 to 2.61 x 10-4 µg/L at 25 degrees Celsius (see reference 7). Given the exceptionally low water solubility limit of decaBDE, it is not expected that this substance will be appreciably taken up by aquatic organisms from the water phase. Therefore, water‑based studies have limited utility when assessing the bioaccumulation potential of substances with extremely low levels of water solubility. One would, however, expect to find decaBDE adsorbed to organic solid materials, including sediments and items consumed in diet. As such, studies that evaluate the uptake and accumulation of chemical substances from sediments and/or soils and diet which measure bioaccumulation and biomagnification factors have greater relevance for the bioaccumulation assessment of highly hydrophobic substances like decaBDE.
c. what is their response to the following position: since bioaccumulation tests based on water do not adequately test for bioaccumulation of some substances taken in by air‑respiring species (such as decaBDE), and since the BAF and BCF tests defined in the Bioaccumulation Regs are based on water, then the BAF and BCF tests set out in the Bioaccumultion Regs can never determine the bioaccumulation potential of certain substances?
The current bioaccumulation criteria identified in the Persistence and Bioaccumulation Regulations were developed from the science of chemical bioaccumulation in fish and are mainly applicable to water‑breathing organisms. As the science of bioaccumulation has progressed, researchers have demonstrated the usefulness of a variety of other measures for establishing whether food web biomagnification is occurring. Additional measures of bioaccumulation that can also be used to address the potential for chemicals to biomagnify in food webs include BMFs, trophic magnification factors (TMFs, sometimes referred to as food‑web biomagnification factors), biota sediment application factors (BSAFs), and soil BAFs. However, these alternative measures are not relevant to the criteria identified in the Regulations, which are focused on aquatic BCF and BAF measures.
In particular, for terrestrial and aquatic/marine birds and mammals, air inhalation and diet are important sources of chemical uptake as you noted in your petition. While partitioning based on the Kow is the main chemical property affecting chemical uptake and elimination of neutral organics in aquatic water‑breathers, this is not the case for air‑breathers. Organism–air exchange involves lipid–air partitioning and is expected to depend on Koa. Koa provides an indication of the tendency of a chemical to accumulate in the tissues of air‑breathing organisms.
Although the Persistence and Bioaccumulation Regulations under CEPA 1999 do not explicitly refer to measures of BMF, TMF or BSAF and do not refer to measures like Koa, concerns of very bioaccumulative substances, including those which biomagnify, are captured by the Toxic Substances Management Policy (see references 2 and 3). Developed during the early 1990s, the purpose of the Policy is to manage very bioaccumulative substances and substances which biomagnify regardless of whether the organisms are aquatic or terrestrial. Criteria in the Regulations are based on those in the Policy that guide the Government of Canada in determining whether substances should be identified for virtual elimination, or life cycle management. In keeping with this policy, actions may be taken to control substances which are shown to biomagnify, or accumulate from sources other than those which are aquatic based. This policy also provides latitude for the federal government to take action on a substance should it be shown to transform in the environment to forms which are bioaccumulative.
(b) I petition the Ministers of Health and the Environment to recommend a change to the Bioaccumulation Regs to employ additional criteria that recognize uptake of a substance through media other than water and species other than aquatic species; to test through exposure to water, food and air; to employ less strict endpoint values and methods; and to recognize other methods for determining bioaccumulation such as modelling.
As mentioned previously, criteria in the Regulations under CEPA 1999 are based on those in the Toxic Substances Management Policy. Given advancements in the state of the science on persistent organic pollutants (POPs) since that time, as well as changes in domestic and international policy surrounding POPs, Environment Canada is considering revisions to the Persistence and Bioaccumulation Regulations. Such a revision would support appropriate decision making in the development of measures for the large number of substances entering the risk management phase under the Chemicals Management Plan. These discussions would give consideration to other measures which recognize uptake of a substance through media other than water (e.g., through air and diet) and organisms who breathe air, rather than water; as well as to other methods like modelling.
If they do not, then I petition them to:
a. advise on the step they will take to ensure that no substances fall through the cracks in bioaccumulation assessments; and
Through a potential review of the Persistence and Bioaccumulation Regulations, it is expected that the resultant revisions, if any, would support the development of measures that are appropriately comprehensive and based on science, to manage substances which may be highly bioaccumulative and/or biomagnify in air‑ and water‑breathing organisms.
b. apply the Bioaccumulation Regs to decaBDE as they are written. The Bioaccumulation Regs state that if neither the BAF nor the BCF of a substance can be determined in accordance with a referenced method, then the test is met when logarithm10 Kow ≥ 5. Since it is the case, as indicated in 1(c) above, that the BAF and BCF tests as set out in the Bioaccumulation Regs can never determine the bioaccumulation potential of certain substances, simply by virtue of the fact that the tests are defined in relation to water, then recourse is had, as required by the actual wording tin the Bioaccumulation Regs, to the log Kow test. DecaBDE meets the log Kow test.
As noted previously, Environment Canada has completed a draft State of Science Report that reviews the available studies pertaining to the bioaccumulation and transformation of decaBDE. This report will be published in the Canada Gazette for a 60‑day public comment period this autumn. This review considers both measured and predicted BAFs and BCFs, and considers whether the criteria for bioaccumulation as identified under the Persistence and Bioaccumulation Regulations under CEPA 1999 are met.
You are correct when you note the Regulations indicate that if neither its bioaccumulation factor nor its bioconcentration factor can be determined in accordance with a method referred to in section 5 then the test is net, when the logarithm of its octanol‑water partition coefficient is equal to or greater than 5. However, it should be noted that section 5 of the Regulations goes on to indicate that “the determination of persistence and bioaccumulation…must be made…taking into account the intrinsic properties of the substance, the ecosystem under consideration and the conditions in the environment.”
The Regulations thus require that professional judgment be applied through the consideration of a particular substance’s intrinsic properties and ecosystem under consideration. While the log Kow is a well‑known indicator of bioaccumulation for some substances, its application requires substantial scientific judgment due to various inherent limitations when used for this purpose. This approach is consistent with guidance identified in the Toxic Substances Management Policy (see references 2 and 3) which provides discussion of the uncertainties relating to the use of Kow for making conclusions on bioaccumulation. In particular, an organism’s ability to metabolize a substance can dramatically decrease its bioaccumulation potential.
Neither BCF nor BAF with measured values in excess of 5 000 are available for decaBDE, and while the possible range of log Kow for this substance exceeds the respective criteria for bioaccumulation in the Persistence and Bioaccumulation Regulations, the use of this data is considered inappropriate. The State of Science Report found that a variety of studies show that both mammals and fish have the ability to likely metabolize decaBDE (see references 5, 6 and 17–20). This process is an important factor in understanding the bioaccumulation potential of decaBDE and has been incorportated into the Report’s modeling estimates for decaBDE BAF and BMF. In addition, as noted previously, log Kow values for substances with extremely low water solubility are highly uncertain.
As a result of the uncertainties associated with the log Kow value for decaBDE and the capability demonstrated by organisms to metabolize this substance, the use of log Kow as an indicator of bioaccumulation is not scientifically appropriate for use in this case.
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