Richard Gleeson
Northern News Services

Yellowknife (Apr 24/02) - Yellowknifers will not be harmed by arsenic concentrations more than 10 times higher than the levels that exist in most of southern Canada, suggests a committee responsible for setting guidelines for clean up of the city's gold mines.

Proposed clean-up standards (parts per million): Residential: 160 Industrial: 340 Giant Mine Boat Launch: 220 Natural or Background level: 150 Level recommended by Miramar: 370 Canadian Council of Ministers of the Environment guideline: 12

The Yellowknife Arsenic Soils Remediation Committee believes the standards are appropriate because arsenic concentrations in city soils are naturally more than 10 times higher than the Canadian average.

"I don't know how you would bring it down below levels that existed before the mines," said Dr. Andre Corriveau, the NWT's chief medical health officer.

Corriveau served as an advisor to the committee. He said as long as the soils are not disturbed the contamination presents no risk.

"I would prefer we focus on the arsenic underground, just waiting to leech into the lake," he said, referring to the 237,000 tonnes of arsenic trioxide dust stored beneath Giant Mine.

Arsenic, which in some forms is known to cause cancer and other serious ailments, is an inseparable part of gold mining. It is both an indicator of the presence of gold and a by-product of the refining process.

For decades, one of the most dangerous forms of arsenic, arsenic trioxide, was emitted from the smoke stacks of the refineries at the Con and Giant mines.

It is the danger presented by the minute airborne particles that settled on the ground around the city that the committee is attempting to address.

Industrial or residential?

The Mackenzie Valley Land and Water Board is responsible for setting the standards for the Yellowknife soils.

Executive Director Bob Wooley said the YASRC guidelines will be reviewed internally. The board will then set the standards.

The standards will have major implications for the cost of cleaning up the mines. In its abandonment and restoration plan for Con mine, a plan yet to be accepted by the MVLWB, Miramar suggests that 370 parts per million would be an acceptable level for soils on its mine site.

The company bases that on the assumption that the mine property will be used in the future for "a similar development."

The city plans to use at least part of the Con leases, Tin Can Hill, for residential development once the mine closes.

The Department of Indian Affairs and Northern Development is financially responsible for cleaning up Giant Mine. DIAND Minister Robert Nault will have the final say on the assessments of the clean-up plans developed for both Giant and Con.

In May, the Royal Military College of Canada at Kingston plans to release its research on the health risks associated with arsenic in Yellowknife soils.

Last week Ken Reimer, the instructor overseeing the research, said the YSARC standards are overly conservative.