The results came three days after a major industrial accident put locals under a water ban and raised fears about the long-term impact on the environment and fish stocks.
A dam holding back the tailings pond at the Mount Polley gold and copper mine in central B.C. failed on Monday, releasing 10 million cubic metres of water and 4.5 million cubic metres of silt into adjacent lakes, rivers and creeks.
Residents were warned not to bathe in or drink the water amid concerns that toxic heavy metals from the mine, owned by Imperial Metals (TSX:III), could pose a danger to human health.
"All results came back meeting the requirements for B.C. and Canadian drinking water standards — this is very good news," Jennifer McGuire of the province's Environment Ministry told a public meeting in Likely, B.C., drawing cheers and applause.
Nevertheless, the ban on using water from the lake and surrounding rivers and creeks remained in effect while officials awaited further testing.
The samples were collected from three locations on Monday, two on Quesnel Lake and one on Quesnel River. Testing still hasn't been completed on the silt that flowed into the waterways.
A memo released by the provincial government to explain the data said none of the test results fell outside of drinking-water guidelines. It also said potential contaminants were all "well below aquatic life guidelines," though officials were still awaiting test results from fish tissue.
"The testing that was done is very, very reassuring," said Dr. Trevor Corneil, the medical health officer for Interior Health. "We are quite pleased."
Corneil said officials remained concerned about Polley Lake, which was also filled with mine waste and flows into a creek that drains into Quesnel Lake.
He said Polley Lake is backed up with silt and there are fears the water, which hasn't been tested, could break free into an adjacent creek and reach Quesnel Lake. Polley Lake must be tested before health officials will consider lifting the ban, he said.
Tim Jardine, who works in the toxicology centre in the University of Saskatchewan's environment school, examined the data and said he was encouraged by what he saw.
He said in an interview that the major concerns would have been arsenic, cadmium, copper, lead and mercury, all of which appeared to be well below water guidelines.
"It all looks low to me — that's good," said Jardine, who helped examine the impact of a massive tailings pond leak from a coal mine in Alberta last year.
"There could be other stuff in the sediment that they haven't yet tested, but this is certainly an encouraging sign."
Still, Jardine, who studies fresh water food systems, said water quality isn't the only potential impact of the spill.
"This suggests that the metals aren't going to have a major impact on the ecosystem, but it's more likely to be that landscape change that was incurred by a big wall of water moving downstream really fast," he said.
The provincial Environment Ministry ordered Imperial Metals Corp. (TSX:III) to immediately take action to prevent additional water and silt from leaking out of the tailings pond, account for what was in the tailings and provide a plan to clean it up.
The province said the company met a Wednesday deadline to provide a plan to stop continued pollution and for a preliminary environmental assessment and cleanup, though the documents have not been released publicly. Additional deadlines are set for next week.
Premier Christy Clark viewed the spill from the air Thursday and described what she saw as "nothing less than astonishing."
"This is one of the cleanest, most pristine lakes anywhere in the world," Clark told reporters after participating in a First Nations ceremony.
"We want to find a way to get it to its previous pristine state."
Clark said the company has legal duties to clean up the spill and could face fines if it fails to comply.
At an unrelated event in Montreal on Thursday, federal Industry Minister James Moore also said taxpayers shouldn't be on the hook for the disaster and that "those who are responsible for this should pay."
David Lacroix, who was at Thursday's community meeting, said he was relieved by the test results, but he was critical of the company.
"I think it's encouraging to hear that the water table is going to be fine, but I still don't understand how this breach could have happened," Lacroix said in an interview.
"As you've seen in other news accounts, people knew this would happen."
A consultant who authored an environmental report in 2011 said this week that the tailings pond water was too high when he examined it, and a former worker has also come forward to say he warned his superiors that the dam wasn't safe.
The company has insisted the dam has never had any problems before, and the province's mines minister has said the consultant who authored the 2011 did not examine the structural integrity of the dam.
Earlier this week, the federal Department of Fisheries and Oceans closed recreational salmon fishing in the Quesnel and Cariboo rivers. Sockeye salmon are currently migrating toward the Quesnel Lake system.
Quesnel Lake and the Quesnel River are considered important breeding grounds for wild salmon, as are other nearby creeks. The system eventually reaches the Fraser River.
The spill has also raised questions about another Imperial Metals project in the province.
The Red Chris Mine in northwestern B.C. is currently under construction, and the company is discussing a potential benefit agreement with a local First Nation, the Tahltan Central Council.
"This latest news obviously means we have new questions and concerns that we must discuss with Imperial Metals about the tailings ponds at Red Chris," Chad Norman Day, president of the Tahltan Central Council, wrote in a letter to his community that was posted to the council's website.
— With files from James Keller in Vancouver
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