The latest water samples from Quesnel Lake and Hazeltine Creek are consistent with previous results and water located outside the impact area remains safe to drink.
Ministry of Environment staff collected water quality samples from Quesnel Lake and Hazeltine Creek at several different sites and depths between Sept. 18 and Oct. 15, 2014.
Results in Quesnel River off the Likely Bridge were below drinking water and aquatic life guidelines. Turbidity levels for Quesnel Lake at Hazeltine Creek and in Hazeltine Creek, located in the impact zone, are above the drinking water guidelines. However, by the time water is measured downstream at the Likely Bridge site, turbidity levels are reduced and within acceptable levels.
Exceedances for drinking water guidelines at Quesnel Lake at Hazeltine Creek included total phosphorus, aluminum, iron and manganese. Additionally, samples collected in Hazeltine Creek exceed drinking water guidelines for arsenic, chromium, copper and lead.
According to Health Canada, there is no evidence of adverse health effects for aluminum, iron and manganese at levels above the guidelines. No health guideline exists for phosphorus. Drinking water guidelines for manganese and iron are based on taste and staining rather than health issues.
Turbidity and total suspended solids levels are above aquatic life guidelines at both sample sites. Exceedances in Quesnel Lake at Hazeltine Creek include total phosphorus, chromium, cobalt, copper, iron, silver, vanadium and zinc. Exceedances in Hazeltine Creek include arsenic, dissolved aluminum, lead, lithium, manganese, mercury, nickel, thallium and titanium.
Long-term monitoring and testing is necessary to help better determine and understand any potential long-term impacts to aquatic life.
Areas where mines are located can often have elevated levels of metals, meaning naturally occurring metal concentrations are potentially much greater in this region than elsewhere in the province.
E.coli results are all below detection levels with the exception of two samples taken from the Quesnel River off the Likely public dock which were at the lowest detection limit. These results meet the provincial drinking water guidelines and reflect typical concentrations of rivers and lakes throughout B.C.
As of Sept. 23, 2014, the Quesnel River off Likely Bridge site has been established as a Federal/Provincial trend monitoring site and is being sampled weekly. Samples collected at this site are sent to two different labs for analysis; the second lab exclusively tests metal and phosphorus samples. These results are currently unavailable and will be posted when received.
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.
In addition to water sample results, reassessment of the high lead result in a single minnow fish, the peamouth chub, collected at Hazeltine Creek on Aug. 27, 2014, is consistent with previous results and confirms the sample is above human consumption guidelines.
The sample was re-analysed in addition to other minnow fish samples. All other minnow and adult fish tissue (trout and salmon) metal results are very low and below the human consumption guidelines for lead.
While the cause of the high lead result is undetermined, it is likely caused by the ingestion of a small lead weight from the angling equipment used to catch the fish. Since the whole fish was tested for metal analysis, the result would include stomach content.
Small-bodied (minnow) fish tissue was reported in a memo dated Oct. 23, 2014, with a single high lead result in a peamouth chub. The result appeared to be an outlier and was sent to the lab for re-assessment. There are currently no lead guidelines for the consumption of fish by wildlife.
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.