The results for tests on water samples taken from Polley Lake on August 7 and 8 show levels very close to those seen prior to the August 4 tailings pond breach, the Ministry of Environment announced August 12.
Concentrations of most tested parameters were found to be below drinking water guidelines as set out by Health Canada and the provincial government, except for pH and aluminum, which had “slight exceedances,” said the ministry in a release.
“Neither of these exceedances presents any risk of adverse health effects and are consistent with water quality results from Polley Lake since the late 1980s,” reads the release. “These results corroborate similar tests taken from the shore of Polley Lake by Imperial Metals.”
Because of the latest results, the water ban has been scaled back to the direct impact zone which includes Polley Lake, Hazeltine Creek and the 100 metres of shoreline where Hazeltine Creek runs into Quesnel Lake.
One sample fell below drinking water guidelines, however. It was taken between Hazeltine Creek and Raft Creek in an area with a “visible suspended sediment plume.” In this sample, phosphorus and aluminum exceeded drinking water standards, and copper, chromium, phosphorus and aluminum exceeded aquatic life guidelines.
“These elevated levels would be expected near an aluminum/copper mine,” said the release.
Further samples are to be taken from Quesnel Lake.
Tissue samples from rainbow and lake trout in Quesnel Lake were taken August 8, 9 and 10, with results expected within two or three weeks.
The ministry said the only reported dead fish was a rainbow trout, and that if any dead salmon are found it is likely not due to tailings pond contamination, but rather due to temperature effects that can be expected in the region during the summer.
