N.W.T. gov't says it followed protocol by doing 2nd round of lead tests instead of notifying schools earlier

The N.W.T government says it followed standard practice when it conducted follow-up testing for lead in the drinking water at two Yellowknife schools instead of blocking the taps off and notifying the public earlier.

"Health experts raised some questions about the sample gathering methods and whether that could have affected the results," Christina Carrigan, senior communications adviser with the Department of Education, Culture and Employment, wrote in an email Friday afternoon. 

In that email, the department said after the initial sample set was done, any result that exceeded the maximum acceptable concentration of lead under Canadian drinking water guidelines triggered a second sample to confirm the finding. 

The department also said the office of the chief public health officer recommended the water not be consumed as a precautionary measure. 

"[Education, Culture and Employment] is now conducting a formal, school-wide series of tests in these two schools to validate the preliminary findings and ensure the safety of the drinking water."

Lead levels in École William McDonald's drinking water were detected at 0.00903 milligrams per litre, while Range Lake North School's levels were 0.025 milligrams per litre. Canada's drinking water guidelines state the maximum acceptable level is 0.005 milligrams per litre. 

Lead was first detected on Jan. 22, and the results were confirmed on April 4. Parents and staff were informed this past Tuesday. 

Dr. Anne Hicks, an associate professor of pediatric respiratory medicine at the University of Alberta, said lead in water and food is absorbed in the body the same way calcium and iron are.

"So into your red cells, into your bones," she said. 

Hicks said it's hard to say how much lead is safe to consume, because everyone absorbs and expels it differently. 

"There's no safe level of lead intake, basically," she said. "The more you take into your body over time, the more likely it is that you'll have an elevated lead level."

She said symptoms of high lead in the body will often emerge later, but most lead exposure is mild in Canada. One sign could be low blood iron, anemia or low red cell counts.

"It can take a long time for these subtle symptoms to show up."

Hicks said the levels found at both schools "are concerning" but that public health officials would best be able to identify the level of risk.