N.W.T. health dept. didn't know Kam Lake is being regularly tested for arsenic

'For some reason it wasn't mentioned, or if it was, we didn't pay attention to it,' said Dr. Andre Corriveau, who issued a public health advisory based on newly unearthed data from 1989 last week.

'We thought we were using the most recent data,' said top doctor who issued advisory based on 1989 report

Kam Lake, in Yellowknife. The territorial government recently issued a public health advisory about arsenic levels in the lake using data from 1989, though Miramar has been testing levels in the lake for at least the last five years. (Curtis Mandeville/CBC)

Publicly-available data shows that arsenic levels in Yellowknife's Kam Lake have been tested as recently as last year, despite a recent public health advisory that relied on data from nearly 30 years ago.

Last week, the Northwest Territories' chief public health officer, Dr. Andre Corriveau, issued an advisory that Kam Lake had arsenic levels over 50 times the recommended level for drinking water. The data used to issue the advisory was from a newly-unearthed report, dating back to 1989.

Cattails on the rim of Yellowknife's Kam Lake. (Curtis Mandeville/CBC)
However, the lake has been tested for at least the past five years by Miramar Northern Mining Ltd. as part of its remediation of the now-defunct Con Mine site. The reports can be found on the Mackenzie Valley Land and Water Board's website.

The latest sample results, from May 2016 to October 2016, show that arsenic levels ranged from 194 to 288 parts per billion.

That's significantly lower than the over 500 parts per billion in the territorial government's data, though Corriveau said it doesn't change the latest advisory. 

The acceptable standard for drinking water is less than 10 parts per billion, according to Health Canada. Kam Lake is not used as a source of drinking water. 

'For some reason it wasn't mentioned'

Last Wednesday's Yellowknifer newspaper reported that Judy McLinton, a spokesperson for the Department of Environment and Natural Resources, said her department was aware of Miramar's testing, and that the results were publicly available.

On Thursday, Corriveau told CBC his department was not aware of the ongoing tests.

Dr. Andre Corriveau, N.W.T.'s Chief Public Health Officer, said that his department relies on other government departments, including the Department of Environment and Natural Resources to let them know about new studies that would be relevant to their public health advisories. An ENR spokesperson said that data was forwarded to Health and Social Services last week. (CBC)

"For some reason it wasn't mentioned, or if it was, we didn't pay attention to it," he said. "And we thought we were using the most recent data that was in my office."

Corriveau said the territory's health department normally relies on other government departments, including Environment and Natural Resources, for new research, and that the departments have regular contact.  

"We rely on ENR to let us know," he said. "We don't do the research, so we try to find out who's doing research and we try to attend the presentations they make, or receive a copy of the publication. And then we look at our advisories and decide if there's a need to update it or not."

In an email to CBC, McLinton said that Environment and Natural Resources forwarded the studies to the Department of Health and Social Services last week.

"This data has been provided to HSS for their information and for consideration regarding its potential relevance to any advisories HSS has issued for this water body," the email read.  

About the Author

Curtis Mandeville

Curtis Mandeville is a reporter for CBC North based in Yellowknife. He is from Fort Resolution, N.W.T.


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