USask team looks for ways to remove toxic tire compound from water

Following the University of Saskatchewan’s successful research into rubber tire particles impacting rainbow and brook trout through urban stormwater, researchers are now getting an opportunity to find out how best to remove the toxin known as 6PPD-quinone.

The new research comes as part of several new projects funded for USask under Research Junction, a collaboration between the university and Saskatoon to apply advanced research methods to solving a range of urban challenges.

Earlier this year, USask researchers determined that 6PPD-quinone could prove fatal to brook and rainbow trout about four days after exposure from stormwater runoff events, even in small concentrations. Vehicle tires simply wear out over time and essentially flake off onto the road, then get washed away by rain into storm sewers.

The name of the compound, 6PPD, is shortened from the industrial chemical N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine.

“Our research aims to develop a treatment system using agricultural residues and investigate its application to remove the toxic 6PPD compounds from urban runoff in Saskatoon to minimize their release into the South Saskatchewan River,” announced Dr. Jafar Soltan, professor of chemical and biological engineering in USask’s College of Engineering, in a statement.

Soltan was awarded $29,300 to develop a cost-effective and eco-friendly treatment system to remove the toxic tire compound from the river.

While no removal method has been announced, some attention has been drawn in the U.S. to constructing bioretention cells, or using biochar, a carbon-rich material produced during pyrolysis that is a thermochemical decomposition of biomass.

Beyond 6PPD-quinone, an antioxidant often used to prevent cracking and discoloration in vehicle tires, the school’s previous research found four bicyclic amines associated with tire rubber manufacturing and present in tire rubber leachate when examining the South Saskatchewan River.

The school also previously studied the toxicity of the chemical compounds for fish using a chemical hazard assessment tool called EcoToxChip, recently developed as part of a large Genome Canada initiative to identify early toxicity indicators for fish species.

Previous research at Washington State University and the University of Washington in Seattle initially discovered the toxic tire compound while  working alongside federal agencies, utilities and conservation groups.

USask research has also shown that 6PPD was not fatal for any Arctic char or white sturgeon during testing.

In California, state legislators are currently trying to pass a proposal to force tire manufacturers to find safer alternatives to 6PPD. The approach has already gained some support from tire companies.