The Britannia mine, located 50 km north of Vancouver near Squamish, BC., operated as a copper mine from 1905 to 1974. Often described as one of the most serious pollutant sources in the Pacific region, runoff that flows through the mine’s abandoned tunnels combine with oxygen and the high sulphide content of the waste rock to create a condition called Acid Mine Drainage (AMD). AMD is caused by a chemical reaction, which results in highly acidic runoff that contains large concentrations of dissolved metals such as copper, cadmium, iron, and zinc. Fisheries and Oceans Canada has undertaken two studies in order to better understand how the runoff from the Britannia mine is affecting aquatic life in local streams, and the body of water they drain into - Howe Sound.

In the first study, juvenile mussels (Mytilus edulis) were used to determine the effects of the discharge on marine life as it drains from Britannia Creek into Howe Sound. The study has found that the accumulation of copper and zinc in mussel tissues increased with proximity to Britannia Creek and was significantly correlated with exposure to dissolved copper in surface waters. Mussels stationed within 2.1 km of Britannia Creek were observed to have significant adverse biological effects including: lower survival rates, length and weight growth rates and condition index than mussels located outside this area. These effects were likely related to exposure to metals from contaminated mine waters, poor feeding conditions, and interactions with natural factors such as salinity and turbidity.

In the second study, scientists compared fish abundance, distribution and survival at contaminated sites near Britannia Creek and unpolluted reference areas in Howe Sound. Biweekly beach seine surveys conducted during April - August 1997 and March - May 1998 showed that species richness and abundance of nearshore fishes were much lower near the mouth of Britannia Creek compared to uncontaminated reference areas. Transplant experiments with marked chum fry (Oncorhynchus keta) indicated that, unlike nearby estuaries in Howe Sound, juvenile chum salmon do not inhabit Britannia Beach estuary for extended periods. Laboratory bioassays using juvenile chum and chinook salmon (Oncorhynchus tshawytscha) confirmed that discharge from Britannia Mine is highly toxic to young salmon and in-situ caged experiments with chinook smolts indicated that surface water near Britannia Creek is more toxic than deeper water. Results from this study demonstrate that nearshore fishes, especially juvenile salmonids, are negatively impacted by AMD from Britannia Creek and, in order to restore productive capacity at Britannia Beach estuary, contamination from AMD must be eliminated.

For more information regarding this study, please contact:
C. D. Levings, Fisheries and Oceans, Science Branch, West Vancouver Laboratory
4160 Marine Drive, West Vancouver BC Canada V7V 1N6  
Phone 604 666 7915, fax 666 3497, email levingsc@dfo-mpo.gc.ca

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