SOMBA K'E/YELLOWKNIFE - A scientist working for the federal government says Yellowknife residents have little to fear from ingesting arsenic in what they eat and drink, even though the city is next door to possibly the most arsenic-contaminated site in Canada.

Dwayne Wohlgemuth poses with a tray of peas growing in soil sold by Arctic Farmer and collected from the Yellowknife area, in his house on May 7. - Tim Edwards/NNSL photo

"Individuals living in Yellowknife are not exposed more than other Canadians," said Bruce Halbert, an environmental scientist and consultant who was been working with the Giant Mine clean-up project since 2000.

"They are at the high end, but not overexposed."

Halbert's "risk assessment" study examines just how much arsenic has found its way into the food chain and onto the dinner table in the Yellowknife area.

The study looked at the amount of arsenic in water, in fish taken from different parts of Yellowknife Bay and Back Bay, berries and medicinal plants used in teas, and in animals such as rabbits and moose wandering through the Giant Mine site.

The study also created hypothetical groups of people living in different parts of Yellowknife, including one living in the old mine town site, which has been vacant for 10 years. The study took into account different diets - some of which adhere to a more traditional diet of country foods, and others more composed of food from the supermarket.

"That assessment established that our highest exposed individuals were in the Giant Mine town site and (the second highest were) on Latham Island and Ndilo, assuming they got fish and ducks from Back Bay and small game from the mine site," said Halbert.

Adults nationwide are exposed to between 0.0001 and 0.0007 milligrams of arsenic per kilogram of food consumed per day. Halbert said his study determined residents of Latham Island following a traditional diet are at the very edge of those average levels, with an intake of 0.0007 mg per kg per day.

The study found that if people were still living at the Giant Mine town site, their level of intake would be 0.0009 mg per kg per day.

Halbert said the levels of exposure were similar to those found in towns in Ontario and Newfoundland, where no ill health effects were reported.

The study was conducted using dozens of previously compiled reports and papers on toxicity in the area from the 1990s and over the last decade. Studies from around Canada and the United States were also referenced. Arsenic is naturally present in the Yellowknife area, but it's the arsenic trioxide - a byproduct from decades of roasting gold ore at Giant Mine - buried underneath the mine that's the biggest cause for concern.

Some of it was dumped right into Great Slave Lake in the mine's early years. Today there are 15 underground chambers, each the size of the Bellanca Building downtown, housing about 237,000 tonnes of the deadly arsenic trioxide dust. There are also 16 million tonnes of tailings stored throughout the Giant Mine property containing moderate amounts of arsenic, which is exposed to the elements and wind.

"Arsenic is considered to be a carcinogen, which means that arsenic can result in some cancer risk," said Halbert.

"That's really saying that if you're overexposed to arsenic, you have a greater risk of experiencing cancer in your lifetime," said Halbert.

Arsenic is highly poisonous. A tablespoon of arsenic trioxide, which is somewhat soluble in water, is enough to kill a person.

Dwayne Wohlgemuth, co-chair of the Yellowknife Community Garden Collective, said his group did some research two years ago on how arsenic affects gardening in Yellowknife. One of the reports the collective looked at was conducted by the Royal Military College in Kingston, Ont., in the late 1990s. which looked at arsenic contamination in the environment around Yellowknife. The report was one of those referenced in Halbert's study.

"Vegetables and berry plants don't take up the arsenic so easily," said Wohlgemuth. "The biggest source of heavy metals (including arsenic) is not necessarily in vegetables, but the soil on the vegetables," he said.

"Washing them is very important."

Wohlgemuth said mushrooms are a different story, and take up contaminants very easily. He warned against eating mushrooms grown in the area.