20K tonnes of soil at Kenilworth reservoir site is contaminated with a carcinogen

Around 20,000 tonnes of soil contaminated with a carcinogen at the Kenilworth reservoir was discovered this summer, and councillors are only just learning about it. 

There is no threat to public safety, according to Andrew Grice, head of Hamilton water. Soil contamination in an older city like Hamilton, especially with its industrial background, isn't out of the ordinary, he said. 

"It's just a part of our life," he said. "But the size of the Kenilworth reservoir, and therefore the magnitude of this, is kind of why we're here in front of you today." 

At the edge of the escarpment and the intersection of Wards 3, 4, and 5, the Kenilworth reservoir is one of two main feeds for drinking water for places on the mountain. 

The contamination was first discovered in June as part of a $6.4 million rehabilitation project. City councillors found out about the high levels of benzo(a)pyrene, which is found in coal tar and often in slag from the steel manufacturing process, for the first time in Wednesday's general issues committee. 

A worker was on site and saw some "visual concerns" with the soil, so they took some samples. When results returned in late June, they revealed high levels of benzo(a)pyrene — a polycyclic aromatic hydrocarbon (PAH), which is a carcinogen. 

Grice said the results from a more thorough analysis came back in August and showed that 50 per cent of the reservoir contained elevated levels of the carcinogen.

Though there were pockets of hot spots, he said, the amount was distributed across area.

He said some levels were six or seven times the set standard, but it wasn't consistent across the entire reservoir. The allowable limit is low in the micrograms per gram range.

It works out to around 15,000 to 20,000 tonnes of contaminated soil. It's been in place since the reservoir was built in 1964, when there weren't robust regulations on soil quality, Grice said. 

Engineering consultant suggests leaving the soil

Samples of the drinking water were taken out of precaution, and no PAHs were found. 

"This contamination of this soil that's been sitting there for almost 60 years, doesn't pose a risk to the health of the public and…doesn't pose a risk to the reservoir and Hamilton's water drinking system," said Dr. Bart Harvey, Hamilton's medical officer of health. 

The province's ministry of environment was contacted, as well as a consulting firm to review options. 

The company's study in October suggested reusing the soil on the reservoir was acceptable from a regulatory perspective, he said.  

But if the funds were available, he said moving the soil elsewhere "probably would not be a bad idea."

Councillor Tom Jackson (Ward 6) said he hoped other councillors heard the suggestion "loud and clear."

It would cost an estimated $6.5 million to take the contaminated soil away and replace it with clean soil.

The material would have to be hauled off to a hazardous landfill, which Grice said might likely be in Quebec. 

The city said staff will look at various options, but not just removing the soil.

Environment Hamilton's executive director Lynda Lukasik says the discovery isn't surprising given Hamilton's industrial history. 

"It was interesting, but maybe not shocking to hear," she said, adding that the discovery can be seen as more "unnerving" because of its location. 

But the talk about human exposure to benzo(a)pyrene has her pointing toward the coke batteries at the steel mills, which release this same containment into the air. 

"Every single day...this stuff is getting into the air that we breathe, and it's impacting some Hamiltonians more than others," she said. 

She said there needs to be more community awareness, and also raised the question on why it took so long for councillors to hear about the soil when it was likely to have public concern. 

The presence of it near drinking water, said Brad Clark, councillor for Ward 9, and the fact that findings were in August, also left him confused on why it didn't come to council earlier.

Grice said that the department tries not to "overreact" to information and wanted to get more information given there was no risk to the public. City manager Janette Smith said the senior leadership team will review. 

Mayor Fred Eisenberger, who found out about the numbers the week before the meeting, said the city should be "cautious and careful." The material is the same as Randle Reef, he noted, though that concentration was clearly much higher. 

"I'm not suggesting that we leave it there, if there's a safe and credible way of removing that. But I think those are still open questions that we need to turn our minds to before we leap into any final decision."

The Ministry of Environment, Conservation and Parks has asked the city to submit a plan on how contractors will deal with the soil, Grice said. The plan included personal protective equipment, like gloves and coveralls, as well as tarping the soil. 

"While there is no legal requirement for the city to remove the contaminated soil, the soil must be managed in a way that prevents off-site adverse impacts," said a spokesperson for the ministry. "If there is a potential for on or off-site impacts, the ministry may require the city to take additional action."

The engineering company will also complete a plan for the soil. 

Construction is expected to wrap up in March 2021, and if the soil is removed, it would start in the new year with a separate contractor.