Industrial Contaminants

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

Click on graph for larger version.

The graph shows that as dioxins in discharges from B.C. coastal pulp and paper mills decreased, there was also a drop in dioxins and furans found in sediments and in crabs near the mill outfalls.

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% decrease in the amount of monitored dioxin in effluent by 1999. After 1999, it was not detectable in the effluent of any mills.

• A 99% decrease in the loadings of monitored furans in effluent by 2004 (not shown on graph). They are now present in minute quantities, below federal discharge limits.

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

• A 96% 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].

Next: Long-Term Deposits of Pollutants in Sediments >>