WILLIAMS LAKE - The latest testing on sediment samples taken by Ministry of Environment staff from the Mount Polley mine site and Hazeltine Creek are consistent with previous sample results.
Sediment samples were taken on Sept. 4, 2014, from three locations: inside the tailings impoundment, outside the tailings impoundment at the breach and from Hazeltine Creek at the Gavin Lake Forest Service Road Bridge.
Test results show these samples exceed some B.C. standards and guidelines; however, they are consistent with baseline tailings samples taken from 2010 - 2014. Results are also consistent with earlier sediment samples taken from inside the tailings impoundment on Aug. 12, 2014, and outside the tailings impoundment at the breach on Aug. 12 and 15, 2014.
The following were identified as exceeding standards and guidelines: copper, iron, manganese, arsenic, selenium, and vanadium. Although these metals are often found in rock and minerals in the natural environment, Interior Health will be monitoring these results for potential long term health risks. Water sourced from outside of the impact zone is considered safe to drink. The current Do Not Use order remains in place for the impact zone.
Guidelines where exceedances were observed include: B.C.’s working sediment quality guidelines for the protection of aquatic life, the contaminated sites regulation sediment quality criteria, and the Canadian Environmental Quality guidelines (CCME) for the protection of environmental and human health.
Pre-breach tailings samples were collected as recently as May 31, 2014, and, along with the average baseline sample results from 2010 - 2014, these pre-breach results show similar metals exceeding the same guidelines.
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.
It is also important to note, these samples were analysed for total metals that are bound to sediment and not dissolved metals in the water that are bioavailable to aquatic life. Long-term monitoring and testing is necessary to help better determine and understand any potential long-term impacts to aquatic life.
All results and explanations are publically available on the Ministry of Environment’s dedicated Mount Polley site: www.env.gov.bc.ca/eemp/incidents/2014/mount-polley.htm
Ministry of Environment