Carcinogen discovered in soil on top of Hamilton’s Kenilworth reservoir

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Hamilton’s public works department says it’s working with Ontario’s ministry of the environment after a cancer-causing agent was found in tonnes of soil at the Kenilworth reservoir expansion worksite.

On Wednesday, city councillors were briefed for the first time by the city’s water department during a general issues committee meeting and told that the matter is of no threat to the public.

Director Andrew Grice said the discovery was made in mid-June during a routine soil inspection tied to a $6.4-million capital project repair of the drinking water storage operation which is one of two reservoirs that services residents on the Mountain.

“As they were they were excavating soil they noticed some visual concerns in a couple of areas,” Grice told councillors.

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Samples were collected by the workers and analyzed with the results returned in late June showing high levels of benzo(a)pyrene – a type of polycyclic aromatic hydrocarbon (PAH), according to Grice.

After learning the scope of the contamination, Hamilton’s associate medical officer doesn’t believe there is any risk to residents since water quality tests in early September showed the content of PAH in the water was less than the allowable concentration by law.

However, in a conference call, Harvey said there was not a “hundred percent” certainty that the risk is minimal.

“I think within the bounds of what we know from the analysis of this, from what we know as to how the reservoir was constructed and is maintained, that there is a minute risk of a sufficient amount, even any amount of this contaminant still finding its way into the reservoir,” Harvey said.

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Grice says the soil has been on the site for close to 56 years and was likely contaminated via slag material from some sort of a steel manufacturing process.

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Specialists in soil management have been on-site and collected more than 190 samples from the scene in June which determined that 50 per cent of the reservoir soil contained various levels of PAHs fairly distributed across nearby fields.

Since October, Grice said the city has been engaged with the ministry of the environment and been regularly discussing a handling plan for the excavated soil which is expected to be used in the Kenilworth project since it meets the legislative criteria for use.

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A spokesperson for the ministry confirmed it met with the City of Hamilton and requested a short-term and long-term soil management plan.

“While the source of the contaminants found in the soil has not been confirmed, the City of Hamilton believes the soil likely came on-site during the construction of the reservoir,” the ministry’s Gary Wheeler told Global News.

“The city advised that it is currently having internal discussions with senior leadership, and potentially city council, regarding budget pressures around soil removal. If the city decides to remove the soil, they will submit an updated soil management plan.”

Wheeler confirmed that there is no legal requirement for the city to remove the contaminated soil — rather it must be managed in a way that prevents off-site adverse impacts.

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Grice says he’s made some queries about the removal of roughly 15,000 to 20,000 metric tonnes of the soil, which could equate to a $6.5-million bill when replacement soil is factored in.

He went on to say that the soil would likely have to be shipped off to Quebec and a landfill that meets legislative requirements to host the waste.

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The city has hired Jacobs engineering for the soil management plan which is expected to be completed in January.

The company is also suggesting that the soil could potentially be safely reused to complete the upgrade at the reservoir, according to public works.

The timeline for the completion of the Kenilworth Reservoir is March 2021 with the city tendering out management of the soil in February of the new year.

Councillors unanimously approved a motion for a staff report on the best course of action.