The latest water samples from Quesnel Lake and Quesnel River are consistent with previous results and Interior Health reaffirms water located outside the impact zone remains safe to drink.

Ministry of Environment staff collected water quality samples from several different sites and depths on Sept. 11, 2014. Results for water quality were below the drinking water guidelines with the exception of total aluminum which was slightly elevated. Results were also below aquatic life guidelines with the exception of copper, which slightly exceeded the chronic guidelines at all sampling sites.

There is no evidence of adverse health effects for aluminum at levels above the guidelines. These samples were collected to target the suspended solids plume associated with the tailings storage facility breach. Samples from within the plume can help determine “worst case scenario,” however, do not reflect water quality throughout the entire water column. Water samples were also collected for caffeine analysis to test for E. coli and results will be reported when available.

Exceedances for aquatic life are based on samples analysed for total metals bound to sediment and not dissolved metals in water that are bioavailable. The exceedances do not automatically indicate impacts to aquatic life. Long-term monitoring and testing is necessary to help determine and understand any potential long-term impacts.

At the time of sampling, biologists noted the water temperature in Quesnel River was colder than previously recorded and the site was cloudy. These characteristics indicate a thermocline tilt, also known as a seiche, occurred where colder water from the bottom of the lake pours out or “sloshes” over the sill between the lake and the river. These tilts, caused by water current, are natural and normal occurrences in the river. If “sloshing” continues, water travelling toward Likely may appear cloudy.

Interior Health continues to advise residents to avoid drinking cloudy water. If they notice increased turbidity, sediment, and/or a change in taste or odour, consider filtration and disinfection per normal water practices or use alternative water sources.

All test results have been shared with local First Nations, the First Nations Health Authority, Interior Health and the Cariboo Regional District.

All results and explanations are publically available on the Ministry of Environment’s dedicated Mount Polley site: http://www.env.gov.bc.ca/eemp/incidents/2014/mount-polley.htm

Media Contacts:

Media Relations
Ministry of Environment
250 953-3834