Winnipeg scientist skeptical of city water monitoring procedures

The boil water advisory was lifted more than 24 hours ago, but questions remain over how the samples at the heart of the Winnipeg-wide scare couldve tested positive for bacteria and E. Coli in the first place.

Six routine water samples taken on Monday showed the presence of bacteria, and E. Coli in some cases. After resampling and retesting, samples came up negative and the city lifted the advisory Thursday.

Mayor Brian Bowman assured Winnipeggers tap water was safe, and always had been, as the original tests were proven to be false positives.

The citys acting director of water and waste said the false positives were a product of either testing or samplingerror.

Rick Holley, a professor at the University of Manitoba and expert in food safety, said that while mistakes like this do happen, they are unacceptable when hundreds of thousands of lives may be impacted.

I still had concerns at that time and still do that the false positives might not be scientifically discredited, said Holley. Its all too easy to continue testinguntil you get the results you want and any results you don't want you discard as being false. That's inappropriate.

Holley said the only way to be sure Winnipeg water is safe is to understand whatcaused the positive results earlier this week.

Why were those six samples positive? There has to be a reason why and that has to be established, said Holley.

One telling detail released by the city was that all of the samples that tested positive were handled by the same employee.

The city provided a list of possible explanations for how the tests came to be positive, including:

• A contaminated water tap or container
• The water being contaminated during sampling
• Mistakes made at the lab during analysis

The city has launched an investigation but admitted that when a similar investigation in 2013 was conducted during an E. coli scare localized to parts of St. Vital, results came up inconclusive.

We were not able to determine the cause, Diane Sacher, the citys director of water and waste, said Thursday. We did a review of our testing and sampling protocol and did make some changes, so obviously we need to do something different.

Holley said while he hopes the city provides more detailed answers and soon, he remains concerned about the citys water monitoring procedures.

Occasionally you will get a result thats not true but you should have your technical staff trained in a way that its not going to yield the kind of system breakdown that weve had this last week in Winnipeg, said Holley.