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Sodium hydroxide to be added to city water

City council is moving forward to reduce lead levels in city water through the addition of sodium hydroxide.

THUNDER BAY - City council is moving forward to ensure the city’s drinking water is safe and lead free by adding sodium hydroxide to the water system at a cost of $264,000 a year.  

Thunder Bay city council voted in favour of accepting the Corrosion Control Plan, following a presentation on a two-year pilot study.

The study took place from January 2015 to January 2017 in the Hodder pressure zone and was meant to confirm that adjusting the pH levels through the addition of sodium hydroxide can reduce lead levels in drinking water.

Approximately 25 per cent of homes in the city tested above acceptable lead levels in drinking water of 10 parts per billion.  The Ministry of the Environment and Climate Change requires that municipalities must have a plan in place to reduce lead levels if 10 per cent of tested results are above the 10 parts per billion.

Introducing sodium hydroxide raises the water’s pH levels, but does not remove lead.

“When you increase the pH of the water, you lower the solubility of the lead compounds coming off of the pipe,” said city environment division planning and research analyst, Erin Marcella-Fui. “It doesn’t get rid of the lead, it lowers the corrosion rate.”

Marcella-Fui and Michelle Warywoda, director of environment with the city of Thunder Bay, assured councillors that adding sodium hydroxide to drinking water is the best option.

“We are adding it at very small increments,” Warywoda said. “It is approved for use in drinking water. It is safe and it is effective.”

Coun. Brian McKinnon wanted to know if the addition would change the taste or odor of the water.

“No, it will not,” Warywoda said. “It will not affect the taste or the smell. We found that with our Hodder pilot study there wasn’t a change.”

Some councilors wanted to know why this was a necessary step, including Frank Pulia, who asked about the effectiveness of running water, or flushing the pipes, to reduce lead levels in individual households.

Marcella-Fui said the Ministry of the Environment does not agree that flushing pipes is effective enough at reducing lead levels and lead must either be removed, or a corrosion inhibitor added to the system.

“We will be out of compliance if we don’t move ahead and would have to go back to the Ministry,” she said.

Coun. Andrew Foulds said he wanted to know how the people of Thunder Bay would be assured that the addition of sodium hydroxide to their drinking water wouldn’t impact bacteria levels.

“People need to be reassured that they are not going to get sick when drinking the water,” Foulds said. “What confidence can you give the people of Thunder Bay that their water will continue to be safe?”

The amount of sodium hydroxide added will be approximately 12 parts per million and will be completely automated and monitored by staff.

“There is no threat posed to the water with the addition of sodium hydroxide,” Marcella-Fui said.

The addition of sodium hydroxide to the city’s water is expected to take place later this year with the cost of $264,000 per year to be included in the 2018 city budget.

Public notices will be made available through the media and water bill inserts. Two public information sessions will also be held on Oct. 4 at the Slovak Legion and on Nov. 9 at the Oliver Road Recreation Centre.  

Doug Diaczuk

About the Author: Doug Diaczuk

Doug Diaczuk is a reporter and award-winning author from Thunder Bay. He has a master’s degree in English from Lakehead University
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