Thunder Bay tests chemical to remove lead from tap water

The City of Thunder Bay is looking at a new way to possibly cut the amount of lead in tap water.

Homeowners north of Arundel Street and west of Hodder Avenue can expect to have sodium hydroxide added to their water later this year.

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The city is undertaking a pilot study to see if adding the chemical can help reduce the lead content in drinking water.

Officials chose that area because because it's the easiest part of the water grid to isolate, due to the pumping station on Hodder Avenue.

"It's the smallest pressure zone we have in the city, so it's easy to isolate. It's very close to Bare Point water treatment plant and a pumping station that we have just for that area," said Erin Marcella-Fui, a municipal planning and research analyst. "It's easy to isolate and just use that area." 

About 600 homes will be affected. The chemical — which in much higher concentrations is corrosive and used to make cleansers and process metals — will be injected right at the pumping station. In small amounts, it is accepted by the World Health Organization for drinking water treatment.

Can't force homeowners' hand

About 7,500 to 8,000 homes in Thunday Bay are thought to still have older lead pipes connecting them to the city's water mains. When water sits in those so-called service pipes for a while, it can accumulate lead, eliciting readings above the Ontario Environment Ministry guideline of 0.01 milligrams per litre.  

Marcella-Fui said part of the problem is that most of those service pipes are on are on private property, and the city can't force homeowners to upgrade their connections to newer copper piping.

"Because we can't make that happen and remove all 8,000, we have to come up, according to the Ministry of the Environment, with a method limiting the amount of lead that leaches into the water," she said. 

Thunder Bay has previously used awareness campaigns to urge homeowners to get rid of lead water pipes, which are generally found in homes built before 1952.

But to make the change from lead to copper lines and pipes on their properties, homeowners must pay the construction and plumbing costs, which vary widely depending on the house but can rise to $2,000 for a service line and $1,500 for internal plumbing.

Taste won't change

Marcella-Fui added that the taste of the water won't change when the sodium hydroxide is added, though the pH — a measure of acidity — will rise from 9.0 to 9.6, meaning tap water for affected residents will become slightly more basic.

The city has baseline data on the current amount of lead in the tap water of a number of homes, so it should be able to compare to see whether the chemical treatment has any effect, Marcella-Fui said. 

An open house next Thursday from 6 to 8 p.m. ET at the Current River Rec Centre will give residents a chance to ask questions and have city officials address any concerns about the pilot project.