A company has been slapped with a hefty fine after 35,000 litres of chlorinated water overflowed into the Sturgeon River from a water main break in 2012.
Chlorine, even at relatively low concentrations such as that contained in municipal drinking water, is toxic to fish causing tissue damage and subsequent death.
Norellco Contractors Ltd. pleaded guilty Thursday to one count of depositing or permitting the deposit of a deleterious substance in water frequented by fish under the Fisheries Act.
The company was hired to replace water main pipes as part of the Mission Avenue construction project from June to August 2012.
While construction work was being done at the intersection of Mission Avenue and Perron Street on June 26, 2012, employees using a track-hoe hit a high-pressure water main.
The rupture resulted in more than 88,000 litres of chlorinated drinking water being released into the excavation site, subsequently overflowing into the Sturgeon River.
The remaining water at the site was pumped into the storm sewer system, which is directly connected to the Sturgeon. The discharge was only re-directed to a sanitary sewer upon advice of a city employee, said an agreed statement of facts.
Just over a week later, a second water main was ruptured on July 7, 2012, when a Norellco employee struck a pipe while operating a track-hoe.
Chlorinated water again overflowed the excavation site and into the Sturgeon.
Environmental impact
If you fill up your home aquarium with tap water your fish will die, said federal Crown prosecutor Erin Eacott.
"There is a common misconception that tap water is not harmful to fish."
Environment Canada conducted an investigation after the second pipe rupture.
They found water samples taken at three different locations in the vicinity of the rupture had "chlorine concentrations acutely lethal to fish."
Municipal drinking water must contain at least 0.1 mg/L of chlorine. Freshwater aquatic life should not be exposed to more than 0.0005mg/L of chlorine under the Canadian Water Quality Guidelines.
A bioassay test – where rainbow trout were exposed to different concentrations of the chlorinated water at the site – found that 50 per cent of the fish died after 96 hours of exposure to the water mixture containing only 13.6 per cent of the chlorinated water.
At a concentration of 25 per cent of the chlorinated water collected, all of the fish died after 24 hours.
In both instances, Norellco did have any resources to de-chlorinate potable water.
"This was grossly negligent. The offence on July 7 was completely preventable," said Eacott, adding that de-chlorination practices are inexpensive measures to adopt.
A plan, submitted by Norellco to the city, stated silt fences would be erected to prevent sediments from entering the storm sewer system and the Sturgeon River, in case of a water main leak.
Silt can clog fish gills, reduce growth rates, decrease resistance to disease and prevent egg and larval development.
No silt fences were put up over the course of construction.
Norellco also did not abide by excavation and trenching policy, as digging must be done by hand or hydrovac when in close proximity to underground pipes or cables, the Environment Canada investigation found.
Norellco was fined $185,000 – $5,000 to be paid as fine under the Fisheries Act and the rest to Environment Canada's Environmental Damages Fund.
Eacott said this is the fourth case in the past several years where water main breaks have resulted in chlorinated water being released into fish-bearing waters.
Clark Builders was fined $285,000 for releasing 12 million litres of chlorinated water into the North Saskatchewan River in July 2009, while working on a project at the Royal Glenora Club.
Alberta has a vast number of fish-bearing waters, said Eacott, and it's important that contractors do not take a lax attitude with regard to their excavation practices.
Creative sentencing
Norellco has also been court ordered to set up an information booth at the tradeshow portion of the annual Northern Construction Safety Officers Conference in Edmonton in March 2015.
Their booth must include facts of the case and the sentence, information about the impact of chlorinated water and sediment on fish-bearing waters and offer comment on how to prevent it from happening again.
Funds collected by Environment Canada's Environmental Damages Fund go towards projects that focus on environmental restoration, research and development and education and awareness.
The funds will be distributed to projects in the same geographic region where the incident occurred.
