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BC Politics

Mount Polley Fish, Water Samples Show High Metal Concentrations

'Some concerns' remain for aquatic life, officials say.

Maura Forrest 23 Aug

Science-focused journalist Maura Forrest is pursuing a Master's degree at the UBC Graduate School of Journalism and is completing a practicum at The Tyee.

The latest results from fish and water samples in Quesnel and Polley lakes show elevated levels of several contaminants, though government officials continue to assure residents that the fish and water are safe to eat and drink.

Some of the fish sampled had selenium in their liver and gonads in excess of guidelines for human consumption. Selenium concentrations in the fish muscle, however, were much lower.

In a press conference on Friday, Environment Minister Mary Polak said people would have to eat one cup of fish liver and gonads every day to be affected by the selenium, which can increase the risk of heart problems and skin cancer at high doses.

The fish tissue also had elevated concentrations of arsenic, copper, manganese, and zinc when compared to fish from 54 other lakes in British Columbia, though levels did not exceed consumption guidelines.

Polak stressed that the results are not surprising, based on the geology of the area. She said that mines are located in areas with high metal content, so higher than average metal concentrations in the environment are common.

"These results are to be expected for fish from Quesnel and Polley lakes," she said. "The flesh of the fish remains safe to eat."

The selenium levels are comparable to those found in fish collected in 2013 and 2014 as part of Mount Polley's selenium monitoring program. According to a Ministry of Environment memo, the contamination is likely "representative of pre-breach conditions as accumulation of metals occurs over a longer period of time."

'Some concerns' for aquatic health

Imperial Metals received approval to begin discharging 1.4 million cubic metres of treated effluent annually from the tailings pond into Hazeltine Creek in 2012. No comparison was made to fish samples collected before 2013, if such samples exist.

Polak also listed a number of elevated metal concentrations in the most recent water samples. Those include deep samples collected from Quesnel Lake near the mouth of Hazeltine Creek, where water and sediment poured into the lake during the Aug. 4 tailings pond breach.

At the mouth of Hazeltine Creek, drinking water guidelines were exceeded for aluminum, phosphorus, iron, and manganese at depths at or below 30 metres.

Aquatic life guidelines were exceeded for copper, phosphorus, aluminum, cobalt, chromium, silver, vanadium, and zinc. Copper and aluminum were also found in high concentrations at other sampling sites.

Jennifer McGuire with the Environment Ministry said there is "some concern with regards to aquatic health."

Some of the results, including copper, chromium, iron, and vanadium concentrations, exceed acute guidelines, which means even short-term exposure could be harmful to fish.

The other metals only surpassed the lower chronic guidelines, and would likely only cause damage if they remain in the water over the long term.

Water ban still in place

Still, it's possible these metals won't pose a threat to humans or wildlife. Ministry memos that accompanied the sampling results pointed out that many of the high levels are for total metals, rather than dissolved metals. That means the contaminants may be contained in the suspended sediment, and may not be leaching into the water in a form that could harm fish.

Sue Pollock with the Interior Health Authority said that most of the metals are deep enough in the lake that they pose no threat to drinking water.

"No water intakes have been exposed to any significant levels of contaminants," she said.

A water ban remains in place for the so-called "impact zone," an area that includes Polley Lake, Hazeltine Creek, and a small area of Quesnel Lake at the mouth of Hazeltine Creek.

In spite of the reassurances, several of the metal concentrations found in Quesnel Lake are substantially higher than anything recorded in a 1989-2014 water quality database for Polley Lake released by the Ministry of Environment on Aug. 11.

Recorded concentrations of aluminum, cobalt, copper, iron, silver, and vanadium don't come close to the recent results from the mouth of Hazeltine Creek. As a caveat, Polley Lake was never sampled below 34 metres, while many of the exceedances from Quesnel Lake occurred at 45 metres or below.

Amy Crook, with B.C.'s Fair Mining Collaborative, said local residents are far from reassured about the safety of the water or the fish.

She said many people in the area depend on fish for sustenance, but they're nervous about eating it, in spite of the government's claims.

"I've heard community members say they're seriously worried about going hungry this year."  [Tyee]

Read more: BC Politics, Environment

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