PCBs in Cormorant Eggs an indicator of toxic contaminants in the Southern Strait of Georgia

What is Happening?

Polychlorinated biphenyls (PCBs) continue to persist in many species of seabirds, suggesting that large amounts of the contaminant remain in the marine environment. Although the manufacture, import and most non-electrical uses of PCBs has been banned in North America since 1977, some uses of PCBs are still allowed. Release of materials containing small concentrations of PCBs to the receiving environment is permitted but is highly regulated.

GRAPH DATA

Double-crested Cormorants in the southern Strait of Georgia are good biological indicators of contaminants because they prey on fish near shore and do not migrate far from this region. Contaminant loads in the eggs of these cormorants reflect the state of this regional marine environment.

Since 1973, PCB levels in Double-crested Cormorant eggs from the southern Strait of Georgia have declined markedly, but in recent years the levels have remained constant.

Similar patterns of declines in PCBs have been observed in eggs of this species in the St. Lawrence estuary and the Bay of Fundy of the Atlantic Coast.

Why is it Happening?

PCBs are very stable compounds. They persist in the environment and are passed up the food chain, with the highest levels accumulating in predatory birds, like the Double-crested Cormorant, and in mammals.

Up until the early 1970's, PCBs were predominantly used as coolant insulants and heat transfer agents in a number of electrical products such as transformers and capacitors. PCBs were also used in a wide variety of products including printing inks, adhesives and paints.

Strict controls on PCB use, import and manufacture have been in place in Canada since 1977. Between 1992 and 2003 there was a 35% decline in PCBs in use. Similarly in BC, PCBs in use (including contaminated mineral oil) declined markedly from 4942 tonnes in 1992 to 2264.6 tonnes in 2003. As of 2002, 5 299.2 tonnes of PCB wastes (including wastes with low concentrations of PCBs, i.e. below 50ppm) were stored at 509 sites in BC.

Source: Environment Canada, Environmental Protection Service, Ottawa, Ontario. 2004.

GRAPH DATA

Despite stringent safeguards, PCBs continue to enter the environment during improper disposal, accidental spills, discharge of industrial and municipal effluents, and leakage from landfills. PCBs also enter local environments by long range transport by air currents.

Why is it Significant?

PCBs are an environmental concern because they persist in the environment, accumulate in the food chain and are toxic. PCBs are known to cause birth defects in mammals and birds and reduced reproduction in fish. For example, bill deformities in cormorants from the Strait of Georgia in the late 1980's (see above picture taken in the late 1980's) are thought to have been caused by the combined effects of dioxin and PCBs (Fox G.C. et al. 1991). Current PCB concentrations in cormorants are below those associated with adverse effects in birds (Tillitt D.E. et al. 1992).

PCBs can also affect human health. Consult Health Canada's web page on PCBs for detailed information.

What is Being Done?

The manufacture, use, import and sale of PCBs has been controlled. The use, transportation, storage and disposal of existing sources of PCBs are being regulated federally under the Canadian Environmental Protection Act (CEPA) and the Transportation of Dangerous Goods Act. The 1977 Chlorobiphenyl Regulations govern material containing PCB levels of 50 ppm or more. The province of B.C. also manages PCB wastes under its Waste Management Act and has specific regulations for its storage, disposal and transportation (see BC Ministry of Water, Land and Air Protection - word search PCBs).

Under CEPA, PCBs are controlled through a cradle-to-grave (from generation to ultimate disposal) approach. As part of this approach, Environment Canada conducts and maintains an annual national PCB inventory, composed of data submitted from each province and territory.

As the existing sources of PCBs continue to pose a hazard to the environment, the federal government is destroying PCBs that are being phased-out or are in storage. High temperature incineration has been shown to destroy PCBs at an efficiency of greater than 99.9999 per cent. Since 1994, a total of 704 tonnes of PCB waste from B.C. has been disposed of at Western Canada's only licenced incineration facility in Swan Hills, Alberta. The Canadian Council of Ministers of the Environment (CCME) has placed a ban on the landfill of any PCB wastes with high concentrations of PCBs (50 ppm or more). In addition, federal PCB Waste Export Regulations prohibits the export of these PCB wastes for land filling purposes in the U.S.

Exposure limits to PCBs in various foods consumed by Canadians has been established by Health Canada. Concentrations of PCBs in typical Canadian diets, individual foods, air and water are also being monitored by Health Canada. Environment Canada monitors air, water and biota (e.g. seabirds such as Double-crested Cormorants). Research to assess the health implications of exposure to PCBs is also ongoing by Health Canada.

For more information contact: laurie.wilson@ec.gc.ca about the wildlife/environmental issues or emmanuel.mendoza@ec.gc.ca about the federal regulations and management of PCBs.

Check the following sites for additional information on this indicator:

• Wildspace™ - Double-crested Cormorant
• Environment Canada - PCB web site
• Toxic Contaminants in Canada's Environment
• Environmental Management Systems Information - PCBs
• Canada's Chlorinated Substances Action Plan
• Water Pollution
• PCB Waste Export Regulations, 1996
• Environment Canada - Global pesticides Release Database
• Health Canada - Food safety and PCBs found in fish

The following Web sites are not under the control of Environment Canada (EC) and they are provided solely for the convenience of users. Environment Canada is not responsible for the accuracy, currency or the reliability of the content. Environment Canada does not offer any guarantee in that regard and is not responsible for the information found through these links, nor does it endorse the sites and their content. Users should be aware that information offered by non Government of Canada sites that are not subject to the Official Languages Act, and to which Environment Canada links, may be available only in the language(s) used by the sites in question.

• US EPA PCB Home Page
• UNEP - Persistent organic Pollutants
• North American Commission for Environmental Cooperation - Status of PCB management in North America
• Polychlorinated biphenyls. ATSDR Toxicological Profile Information Sheet

For references used for this indicator click here.