(Richard Gleeson/CBC)Winter is returning to the subarctic city of Yellowknife, bringing its snow and ice, the only barriers between people and a toxic legacy of the city's gold mining history. 's chief public health officer, says the Canadian drinking water guideline limit of 10 parts per billion (0.01 ppm) "is very strict." "To be slightly above drinking water guidelines for swimming, even for wading and the odd gulp of water, would be entirely safe." (The Canadian Press)Arsenic concentrations in soilIn a presentation Yellowknife city officials give on moving the city's drinking water intake to Yellowknife Bay, the city notes that water in the bay has concentrations below the drinking water limit. But the presentation notes that the "average natural background" concentration of arsenic in Yellowknife lake sediment and soil is 150 ppm.

Source: CBC News October 24, 2016 00:00 UTC