A research team has concluded that Silver Hill’s problem with toxic gas began four years ago when the province capped an artesian well that was spewing contaminated water into Big Creek.
Dr. Richard Jackson of the University of Waterloo likened the repair on North Walsingham Road 10 to plugging the downspout of an eavestrough. The water behind the stoppage has since backed up. This has raised the surrounding water table and created a number of unintended consequences.
On July 9, Jackson said the higher water table in Silver Hill has allowed naturally-occurring methane gas to combine with sulphur deposits to create hydrogen sulphide fumes in dangerous concentrations.
“This is not an abandoned gas well problem,” Jackson told Norfolk council. “It’s a water problem.”
The diagnosis points toward a solution – albeit an expensive one – for the abandoned gas well on Forestry Farm Road north of McDowell Road East. The well in question is spewing dangerous amounts of hydrogen sulphide gas in a wetland area.
Jackson and his team have concluded that drilling a relief well will lower the water table beneath the layer of sulphur in the ground that is producing the poisonous fumes.
County staff estimates the solution could cost $1.5 million. Norfolk council believes the province should bear the expense.
Jackson has shared his findings with the Ministry of Natural Resources and Forests – the agency that capped the Big Creek well in 2015 – but says the province is reluctant to acknowledge his conclusions.
“As you have heard, MNRF doesn’t share that conviction,” Jackson said. “Why exactly we don’t know. We don’t believe this is anecdotal. It is much worse than that.”
MNRF plugged the artesian discharge because it contained elements that are toxic to aquatic plants, fish and other wildlife in high concentrations. Examples include chloride, sulphite and iron.
Jackson said capping the discharge had an immediate impact on several abandoned gas wells, some as far away as three kilometres.
Emissions from a nearby gas well on North Walsingham Road 10 were so high that the Haldimand-Norfolk Health Unit ordered homes in the neighbourhood evacuated in the summer of 2017. MNRF capped that well at a cost of about $500,000.
In recent months, Norfolk County has monitored emissions at homes in the area of the problem well on Forestry Farm Road.
With game plan in hand, Norfolk has directed staff to prepare the groundwork for de-watering the wetland. If successful, this will stop the emissions that make the surrounding neighbourhood smell like rotten eggs.
“Because of the overwhelming public health concerns caused by this leaking well, council has supported moving forward with this plan immediately,” Mayor Kristal Chopp said July 11 in a news release.
“However, we demand the province make things right and fully fund these remediation efforts, which are only necessary because of their previous plugging of abandoned wells.”
The work will begin in earnest once Norfolk secures a funding commitment from the Ford government.
Jackson is a hydrogeologist. He warned that Norfolk’s problem with toxic emissions promises to get worse. Jackson suspects the problem will become general across North America in the years to come.
Norfolk County has opened a long-term file on the issue because the county is home to 1,600 abandoned gas wells.
Haldimand’s position is even more precarious. The number of potentially problematic wells there is in the range of 6,000 arising from the thriving natural gas industry the county had more than 100 years ago.
Trouble is looming, Jackson said, because of the ad-hoc methods used to cap exhausted wells in the 1950s and 1960s. Jackson said contractors would jam rubble, tree trunks and other scrap items into shafts before capping them with concrete.
Problem is, hydrogen sulphide gas is corrosive and is slowly breaking down these materials. The gas is also eating away at metal liners left behind in the bore holes.
Before long, Jackson says the capping efforts of the past will be undone and hydrogen sulphide will rise to the surface unimpeded in areas where it is currently not a problem.
“It’s happening all across Southwestern Ontario,” Jackson said. “Those were the standards of the day. There is nothing illegal about it. It’s just totally wrong as a method for capping these wells.”
Among its other qualities, hydrogen sulphide gas is also flammable. It is a frequent byproduct of natural gas production and is produced in the presence of rotting organic material.
In low concentrations, fumes will irritate eyes and breathing passages and can induce headaches. Reliable, systematic studies on the long-term effects of hydrogen sulphide exposure have not been performed.