Environmental Trends 2007

Contaminants

Dioxin and Furan Levels in Pulp Mill Effluent, Sediments and Crabs

As dioxins in discharges from B.C. coastal pulp and paper mills decreased, there was also a drop in dioxins and furans in sediments, and in crabs near the mill outfalls.

Source: Pollution Prevention and Assessment, Environmental Protection, Environment Canada , 2005.

TEQ = Toxic equivalent concentration; used to standardize the total concentrations of the different dioxins and furans

High concentrations of dioxins and furans (by-products of pulp bleaching processes) were found in shellfish near coastal pulp and paper mills in the 1980s. This prompted federal and provincial regulations requiring the mills to eliminate these chemicals from effluent.

As a result there has been:

• A 95 per cent decrease in the amount of monitored dioxin in effluent by 1999. It has not been detectable in the effluent of any mills since then.

• An 85 per cent decrease in dioxins and furans in the sediments near pulp mill outfalls.

• A 96 per cent decrease in dioxins and furans in the digestive gland (hepatopancreas) of Dungeness crabs living near mill outfalls.

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