The latest water samples collected from Quesnel River off the Likely Bridge between Nov. 27 and Dec. 15, 2014, and Quesnel River off the Gravelle Ferry Bridge between Nov. 26 and Dec. 17, 2014, are consistent with previous results, according to a Ministry of Environment press release on Jan. 13.
Results for water quality at both sample sites show turbidity levels above the British Columbia drinking water guidelines and total aluminum above Health Canada drinking water guidelines
Results for water quality from the Quesnel River off the Gravelle Ferry Bridge show exceedances for total suspended solids, total iron and total phosphorus.
According to Health Canada, there is no evidence of adverse health effects for aluminum at levels above the guidelines. Iron and phosphorus drinking water guidelines are based on staining and taste, not health effects.
The Gravelle Ferry Bridge site is also subject to influence from several small tributaries and the Cariboo River. All E.coli results meet the provincial drinking water guidelines.
Results for aquatic life at both sample sites show total copper levels and dissolved aluminum above the chronic and acute water quality guidelines.
Additionally, results collected from Quesnel River off the Gravelle Ferry site show exceedances for total phosphorus and total chromium above acute water quality guidelines.
Long-term monitoring and testing is necessary to help better determine and understand any potential long-term impacts to aquatic life.
Interior Health reaffirms that all chemical sampling on surface water located outside the impact zone meets safety guidelines.
Residents using surface water are advised to treat water for pathogens (germs) found naturally in surface water.
Residents unable to treat their water should boil all water used for drinking, washing fresh fruits and vegetables and making ice for one minute or use water from an alternative potable water source.
As a result of the annual fall overturn of the lake, samples collected at both sites continue to indicate increased turbidity into the winter. Fall overturn occurs when warm surface water of the lake cools allowing the cooler and deeper waters to mix with the surface water of the lake, creating a more uniform state within the lake.
Mount Polley Mining Corporation will deliver water and install finer filters to residents drawing water from Quesnel Lake during this period of high turbidity.
Both sample sites are part of the federal/provincial trend monitoring program and are sampled on a regular basis.
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 publicly available on the Ministry of Environment’s dedicated Mount Polley site: http://www.env.gov.bc.ca/eemp/incidents/2014/mount-polley.htm.