The gas that closed the private school on Gray Street may have contained deadly hydrogen sulphide, says an Acadia University aquatic ecologist. Sometimes called swamp gas, it has a characteristic rotten-egg smell and can be produced by organic matter decaying in an oxygen-free environment like that under the frozen pond.
“Don’t mess around with it,” said Dr. Michael Brylinksky, professor of aquatic ecology at the Acadia Centre for Estuarine Research. Asked if the gas is dangerous he said “Oh Jesus, yes.”
But expert opinion is divided on the issue and this quarry pond, on Clifton Avenue near the school, may not be dangerous because a drain was installed by its owner.
According to Dr. Brylinsky, organic matter that contains sulphur can’t decay to relatively harmless SO4 molecules in an oxygen-poor environment, which can happen when a sheet of ice forms over a lake. Instead, sulphur decays to H2S, a gas as deadly as hydrogen cyanide. Normally the gas is dispersed but a spring thaw may release it in large quantities if it has been trapped by the ice until then.
People are very sensitive to the rottenegg smell of the gas but somebody with a bad cold could be more vulnerable, says Dr. Brylinsky.
The gas is commonly found around manure stockpiles, mines, hot springs and the holds of fishing boats. It is a known industrial hazard especially in natural gas and oil wells.
But Eric and Karen Stephens, who own about half of the property containing the quarry pond, say it is perfectly safe. Stephens, who has improved the property over the past 18 years, filled in the bottom so the remaining gypsum doesn’t come in contact with the water and created his own storm sewer which drains the pond when the level rises due to rain.
The couple say some trout are left over from the 1,500 fish they stocked it with— cormorants got most of them. Other wildlife in the lake include turtles, goldfish, ducks and “thousands of minnows” according to Karen Stephens.
As for the smell. “It’s the sewer,” she says. Other academics tend to dismiss the hazard.
“[H2S gas] is possible, but I wouldn’t suspect this is a hazard,” said Cliff Stanley, professor of geochemistry at Acadia. “The minute that gas gets out it’s going to be diluted by air— if the gas escaped into a building, I’d be concerned.”
Dr. Ian Spooner, a professor of earth and environmental sicences at Acadia, takes it more seriously. “If I was a school trustee I would have it tested.”
Neither the provincial departments of environment or labor have hydrogen sulfide detectors according to spokesmen March 9.
