Chloride levels are steadily rising in our drinking water

WATERLOO REGION — For years doctors have been warning patients to reduce their salt intake. Now environmentalists are expressing similar concerns regarding the amount of salt being used on sidewalks, roads, parking lots and driveways.

The chloride found in road salt is seeping into both surface water — like creeks, streams, rivers and melted ice — as well as ground water aquifers, from which we draw our drinking water. Dan Meagher, supervisor of Waterloo Region source water protection programs, says chloride levels in groundwater have been noticeably increasing since the region started monitoring it in 1973.

“We first started noticing it 20 years ago and it’s been trending steadily up,” he said.

According to charts provided by Waterloo Region, chloride concentrations at Cambridge’s Middleton Street Pumping Station, where much of the city’s drinking water comes from, was about 50 milligrams per litre in 1973. By 2015, chloride concentrations there had risen to roughly 200 mg/L.

Greater still, concentrations at two other Cambridge wells have risen beyond 400 mg/L. The Ontario drinking water objective for chloride is 250 mg/L. At this level water has a salty taste.

“The highest levels in Cambridge would be in the Middleton and Elgin Street wells to the south and the Pinebush wells to the north,” Meagher said. “The basic reason boils down to there being a lot of paved surfaces and parking lots nearby and fairly high density, meaning a lot of oversalting during the winter.”

Meagher explains that the problem is a byproduct of the region’s rapid growth, as former green space is replaced by more homes, businesses, roads, sidewalks and parking lots. What heightens the concern locally is that Waterloo Region relies on groundwater for the bulk of its urban drinking water.

Sandra Cooke, senior water quality supervisor with the Grand River Conservation Authority, puts the issue into perspective.

“We’ve been watching this for some time,” she said. “It’s a North American issue, especially in areas where they get a lot of snow and use salt on the roads. Once the chloride in the salt is dissolved in water it’s hard to get out.”

Cooke said the issue has become a real concern within the GTA, where rapid urban development has created many more hard surfaces like roads, which need to be salted in the winter.

The Region of Waterloo has just launched this winter’s public education program concerning salt management. The region staged the first of a series of popup displays this past Saturday at the Dundas Street Canadian Tire in Cambridge and will stage a second display at Lowe’s on Feb. 2. Other pop-up displays are also planned for locations in Kitchener and Waterloo.

Meagher said the effort to curtail the use of salt by the region goes beyond the pop-up displays. It has also closed a number of paved surfaces for the winter to reduce salt use. Cambridge has joined in that effort closing some of the paved areas around Historic City Hall. The cities of Kitchener and Waterloo have taken similar action.

“The Hamilton Family Theatre in Cambridge is also closing an area,” Meagher said.

Meagher said the program understands that stopping salting completely is not a realistic option, however, salt use can be reduced by shovelling or plowing first, using salt wisely or using sand or no-clumping cat litter for traction, wearing winter boots with good treads or using snow tires on your car.

Cooke said the easiest way of reducing chloride contamination of ground and surface water is “at the source.”

“The trick is to find a balance. Think twice before using salt. It’s the easiest and cheapest way of reducing contamination.”

Another area Cooke is working on is the raised levels of chloride contamination in the Speed River. She is working with municipal water managers in Guelph and Hespeler to reduce the amount of chloride discharged into the river from wastewater facilities.

A water managers’ working group has been formed by municipal water and wastewater managers from across the Grand River watershed to address water quality concerns. One area they are exploring is finding better ways to deal with water softener salt.

“We are looking at a number of alternate technologies right now,” she said. “It’s another way we are looking at how to reduce salt use.”