Industrial Contaminants

Overview - What is Happening?

A variety of persistent pollutants, largely from past industrial activities, are still detectable in B.C.’s coastal environment. These include PCBs, dioxins and furans, mercury, and DDE (a breakdown product from the pesticide DDT). All of these substances are known to be threats to human health and the environment. They persist for many years in the environment and continue to accumulate in living organisms.

With each step up the food chain, persistent pollutants become more concentrated in the bodies of animals. Animals near the top of the marine food chain (such as sea birds, seals, and killer whales) carry higher concentrations of contaminants than are found in the general environment.

Regulatory controls introduced over the past 25 years have decreased the levels of PCBs, dioxins, furans, mercury, DDE, and organochlorine pesticides in the environment. Except at contaminated sites, concentrations in the air, water, and environment are now generally low. What residues there are, however, will likely continue to circulate in the environment for decades.

New industrial contaminants also continue to emerge as issues. For example, the PBDEs, which were used to replace PCBs, have recently become a focus of concern. Levels are rising quickly in animal tissue and the general environment.

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WHY IS IT HAPPENING?

In the early to mid-1900s, many contaminants were discharged into the environment through practices that are unacceptable today. At the time, the hazards were unknown. Residues accumulating in people and toxic effects on birds and other wildlife stimulated the campaigns to control the release of persistent contaminants.

Despite regulations and controls, however, there are still low levels of contaminants entering B.C.’s environment from such sources:

• Local, industrial and other activities, especially from combustion processes. Burning salt-laden wood in boilers or trash in backyard burn barrels are examples of activities that continue to produce dioxins and furans.

• Breakdown processes in soils and sediments that are still releasing contaminants (such as DDT) from past uses.

• Accidental releases or spills of controlled pollutants.

• Use of PBDEs in furniture, textiles, plastics, and other consumer goods.

• Transport of chemicals over long distances in the atmosphere from other parts of the world where they are still in use.

Sources of contaminants and how they move in the environment.

Click on image for larger pdf version.

For detailed information, including graph data, see In-Depth report [pdf].

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