Polybrominated Diphenyl Ethers (PBDEs) in Fish and Sediment 

Polybrominated diphenyl ethers (PBDEs), a group of chemicals^[1] used as flame retardants, are considered dangerous for wildlife. PBDEs build up in living organisms, and remain in the environment for long periods after their release. The PBDEs in Fish and Sediment indicators report on the occurrence of PBDE concentrations above or below Federal Environmental Quality Guidelines (FEQGs) in fish tissue and sediment. FEQGs are numerical limits established under the Chemicals Management Plan (CMP) to protect aquatic life, and therefore concentrations below the guidelines are not of concern; concentrations above guidelines indicate that further evaluation may be required.

PBDEs are persistent organic pollutants (POPs), and are considered high-priority chemicals under the CMP. Currently, the use of PBDEs is declining because most commercial mixtures containing these chemicals have either been voluntarily phased out by manufacturers or are subject to restrictions in Canada. The Government of Canada has developed a Risk Management Strategy for PBDEs with the objective of minimizing their release into the Canadian environment. This includes prohibition of the manufacture of tetraBDE, pentaBDE, hexaBDE, heptaBDE, octaBDE, nonaBDE and decaBDE; in addition, the use, sale, offer for sale, and import of tetraBDE, pentaBDE and hexaBDE is prohibited.

Canada is also a party to two international agreements that restrict and ultimately target the elimination of the production, use, trade, release and storage of PBDEs: the Stockholm Convention on Persistent Organic Pollutants and the Protocol on Persistent Organic Pollutants (POPs) of the United Nations Convention on Long-range Transboundary Air Pollution (LRTAP). The objective of these international agreements is to protect human health and the environment from POPs.

Long-range transport of PBDEs to Canada, potential presence in imported products, widespread use in the past, and slow breakdown following release means that PBDEs still remain in the Canadian environment. Current human exposure to PBDEs is well below levels that are considered to be of concern.

PBDEs in fish tissue

Between 2008 and 2010, Environment Canada conducted fish sampling in 11 drainage regions and analyzed PBDE concentrations in fish tissue of four subgroups for which guidelines have been set: triBDE, tetraBDE, pentaBDE and hexaBDE. The analysis found that concentrations of triBDE, tetraBDE and hexaBDE in most drainage regions were below the guidelines. Levels of tetraBDE in the Great Lakes and pentaBDE in almost all the drainage regions exceeded the guideline levels.

The table indicates, for each PBDE subgroup (triBDE, tetraBDE, pentaBDE and hexaBDE), drainage regions where no fish samples returned a concentration reading above the guideline and drainage regions where at least one fish sample returned a concentration reading above the guideline, for the period 2008 to 2010. The guideline was exceeded in all drainage regions except for Maritime Coastal for pentaBDE, whereas the guideline for tetraBDE was only exceeded in the Great Lakes.

Table 1: Comparison between PBDE subgroup concentrations in fish and guidelines, 2008 to 2010

Sampled drainage regions	triBDE	tetraBDE	pentaBDE	hexaBDE
Pacific Coastal	No	No	Yes	No
Columbia	No	No	Yes	No
Yukon	No	No	Yes	No
Peace–Athabasca	No	No	Yes	No
Lower Mackenzie	No	No	Yes	No
Assiniboine–Red	No	No	Yes	No
Lower Saskatchewan–Nelson	No	No	Yes	No
Churchill	No	No	Yes	No
Great Lakes	No	Yes	Yes	No
St. Lawrence	No	No	Yes	No
Maritime Coastal	No	No	No	No

Legend
No	No sample collected in the drainage region returned a concentration reading above the guideline.
Yes	At least one sample collected in the drainage region returned a concentration reading above the guideline.

Note: Measurements were made in 522 representative predatory fish (Lake Trout, Walleye, Cutthroat Trout, Rainbow Trout or Brook Trout) collected from 11 drainage regions from 2008 to 2011.
Source: Environment Canada (2012) Chemicals Management Plan Environmental Monitoring and Surveillance Program.

PBDE trends in fish in Lake Ontario

To provide context on changes through time, additional data showing pentaBDE concentrations in Lake Ontario fish are presented for the period 1997-2010. Since 1997, the concentrations of pentaBDE in Lake Trout collected from Lake Ontario have declined at an annual rate of 4%. Despite this decline, levels of pentaBDE in fish were still above the guideline in the most recent years of monitoring. Currently, there is insufficient data to determine the trends of PBDE concentrations in fish from other Canadian drainage regions.

PentaBDE concentrations in Lake Trout from Lake Ontario, 1997 to 2010

Note: PentaBDEs are expressed in annual geometric average in this chart. A trend curve line is reported only when a statistical trend is detected at the 95% confidence level. Other PBDEs sampled are triBDE, tetraBDE, hexaBDE, heptaBDE, octaBDE, nonaBDE and decaBDE.
*In 2010, Environment Canada has developed Federal Environmental Quality Guidelines (FEQGs) for PBDEs to assess the ecological significance of levels of PBDEs in the environment.
Source: Environment Canada (2012) Chemicals Management Plan Environmental Monitoring and Surveillance Program.

PBDEs in sediment

Between 2007 and 2010, Environment Canada conducted sediment sampling in 10 drainage regions, and analyzed sediment concentrations for 6 subgroups of PBDEs having guidelines (see Table 2). The analysis found that sediment samples from the Pacific Coastal, Great Lakes and St. Lawrence drainage regions had pentaBDE and decaBDE concentrations above FEQGs. Sediment from the Lower Saskatchewan–Nelson drainage region had only total pentaBDEs above guideline levels. All other subgroups of PBDEs were below the guidelines for all regions where sampling occurred.

The table indicates, for each PBDE subgroup (triBDE, tetraBDE, pentaBDE, hexaBDE, octaBDE and decaBDE), drainage regions where no sediment samples returned a concentration reading above the guideline and drainage regions where at least one sediment sample returned a concentration reading above the guideline, for the period 2007 to 2011. Sediment samples from the Pacific Coastal, Great Lakes and St. Lawrence drainage regions had pentaBDE and decaBDE concentrations above the guideline. Sediment from the Lower Saskatchewan–Nelson drainage region had only total pentaBDE above guideline levels.

Table 2: Comparison between PBDE subgroup concentrations in sediment and guidelines, 2007 to 2011

Sampled drainage regions	triBDE	tetraBDE	pentaBDE	hexaBDE	octaBDE	decaBDE
Pacific Coastal	No	No	Yes	No	No	Yes
Okanagan–Similkameen	No	No	No	No	No	No
Columbia	No	No	No	No	No	No
Yukon	No	No	No	No	No	No
Assiniboine–Red	No	No	No	No	No	No
Lower Saskatchewan–Nelson	No	No	Yes	No	No	No
Great Lakes	No	No	Yes	No	No	Yes
St. Lawrence	No	No	Yes	No	No	Yes
Maritime Coastal	No	No	No	No	No	No
Newfoundland–Labrador	No	No	No	No	No	No

Legend
No	No sample collected in the drainage region returned a concentration reading above the guideline.
Yes	At least one sample collected in the drainage region returned a concentration reading above the guideline.

Note: 132 surface sediment samples were collected in 10 drainage regions for the years 2007-2010.
Source: Environment Canada (2012) Chemicals Management Plan Environmental Monitoring and Surveillance Program.

Related indicators

• Canada’s Freshwater Quality by Region

Other information

• Polybrominated Diphenyl Ethers in the Canadian Environment
• Polybrominated Diphenyl Ethers (PBDEs)
• Health Canada Fact Sheet on Polybrominated Diphenyl Ethers (PBDEs) in Fish
• State of the Great Lakes 2012 - Draft Indicator Reports - Contaminants in Whole Fish (PDF; 570 KB)

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[1] PBDEs include 209 different compounds classified into 10 different subgroups known as homologues (subgroups) based on the number of bromines atoms they contain (e.g. triBDE contains 3 atoms of bromine).