Cleanup officials confident contaminants being contained
SYDNEY — Officials associated with the cleanup of Canada’s worst toxic waste dump are confident they are fully containing a host of highly toxic contaminants at the former tar ponds and coke ovens sites.
It was concern over future contamination that prompted a former worker on the cleanup to snap a few pictures during last year’s remediation of the former Domtar site and associated tar cell site — one of the more contaminated properties in the area.
The pictures show what looks like a blob of liquid coal tar on the surface of the site, which was being excavated and prepared for capping with protective layers of slag, clay and topsoil.
Joel MacLean, chief operating officer of Nova Scotia Lands Inc., which was handling the remediation of the site for the project’s main overseer, the Sydney Tar Ponds Agency, said it would not be uncommon to find coal tar on the surface while remediation efforts were underway.
“The Domtar site was one of the worst contaminated sites and we processed some 200,000 tonnes of contaminated soil from that site,” he said.
“I am very confident that all contaminants on that site will be contained,” said MacLean, adding it would be extremely upsetting for all involved to find any evidence of coal tar or other pollutants percolating to the top.
“We have no reports of anything showing up after remediation.”
The $400-million federal-provincial cleanup of the Sydney tar ponds and associated sites was first announced in 2004 and is to be completed by 2014. The project is attacking the toxic legacy of nearly a century of steel making and byproduct industries.
The obvious objective is to rid the location of its poisonous contaminants, and to ensure the site remains free from future contamination.
Tar ponds agency workers Jerome MacNeil, contract manager, and George Hennick, operations manager, report that some 25,000 tonnes of coal tar were removed from the cell and treated.
“We have yet to see any oozing of coal tar material from that site,” said MacNeil, adding the site is regularly monitored by wells, surface and groundwater testing, area walks and other analysis.
“The site now is actually pretty clear,” said Hennick, noting that about 109 million litres of groundwater has already been treated and weekly checks for metals and other contaminants have produced no sign of any leakage.
“Any known liquid coal tar has been removed,” he said.
The project’s remediation monitoring oversight board, appointed by the province to oversee the Department of Environment’s role in the cleanup, also appears to be confident that monitoring measures now in place are sufficient to warn of any pending danger.
“We feel that this project likely receives more monitoring and oversight than any other project in Canada,” states the board’s annual report, delivered in June.
The report noted that the environment department received only 59 public complaints on the project between October 2009 and June 2011, with the overwhelming majority dealing with odour complaints.
“As a part of the monitoring program, an average of four on-site inspections are carried out each week and staff closely monitor any complaints from the public,” the report says.
As land becomes available, MacLean said it will be offered for commercial enterprises to join the newly formed Harbourside Commercial Park, which now boasts about 20 businesses.
Tar ponds agency spokesperson Tanya Collier MacDonald said future uses for the former tar ponds site have not yet been determined and will be subject to community input.
Terry MacPherson, senior manager of the environment department’s Sydney tar ponds regulatory branch, said his office of seven includes two inspectors and three environmental engineers.
MacPherson said staff visit the site usually every day and so far have not received any indication or reports of leaking contaminants.
After years of public meetings, consultant reports, preliminary studies and other discussions, it was agreed to treat the tar ponds with a process known as solidification and stabilization.
The process combines contaminants with a cement powder to prevent any future movement within the soil. The site will then be capped with a combination of slag, clay and topsoil and will be subject to monitoring for 25 years.
Contamination at the coke ovens is being treated with a form of bioremediation through which hydrocarbon-eating bacteria and nutrients are tilled into the upper surface of the soils. The area is again capped.
The north and south tar ponds cover an area of 31 hectares (77 acres) and are home to a toxic cocktail of 700,000 metric tonnes of contaminated sludge.
The coke ovens site stretches across 68 hectares (168 acres) and contains 560,000 tonnes of contaminated soil. The old steel mill site covers 350 acres and is also being remediated.
Cancer-causing contaminants to be found on the site include polychlorinated biphenyls (PCBs), benzene, naphthalene, coal tar, lead, polyaromatic hydrocarbons (PAHs) and arsenic.
Measures to prevent future contamination include the installation of vertical cutoff walls on the coke ovens grounds that help control the flow of groundwater over the site.
One wall stretches across the north side of the coke ovens site, while a second runs on the south and west sides.
Two interceptor pipelines have also been installed to bring the water to an on-site water treatment plant.
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