Main Emission Sources

It is difficult to generalize the sources of POPs. The major sources vary depending on whether it is a pesticide, industrial chemical or unintentional by-product.

While many industrial and pesticidal POPs (such as PCBs, DDT and the other intentionally produced POPs listed in the Stockholm Convention) have been banned or severely restricted in Canada for years, they are still produced, used and released in a number of other countries. Most of the POPs currently entering the Canadian environment come from foreign sources in North and Central America, Eastern Europe and Southeast Asia via atmospheric transport. Most levels of these “legacy” POPs are slowly declining in the Canadian northern atmosphere.

Significant sources of unintentional releases of dioxins and furans in Canada have historically been pulp mills using chlorine bleaching, wood preservation facilities, waste incinerators, cement kilns burning hazardous waste, iron sintering plants, coastal pulp and paper boilers burning salt laden wood, steel manufacturing, electric arc furnaces, and conical municipal waste combustors. Other potential sources of dioxin/furan releases for which characterization studies are underway include: on-site residential waste combustion, residential wood combustion and open-burning of municipal waste.

In addition to the “legacy” and unintentionally produced POPs, other “emerging” chemicals of concern are being found in Canada’s environment.  Canadian and international scientific research and risk assessment s are currently underway to determine whether these chemicals have all the POP characteristics (toxicity, persistence, bioaccumulation and capability for long-range transport).  If the POP criteria are met, they would be targeted for virtual elimination under Canada’s Toxic Substances Management Policy and be candidates for international control under the UNECE POPs Protocol and/or Stockholm Convention on POPs.