How many times do we flush water down the drain in our homes without ever wondering where it will go and what it might affect further down the line? Similarly, when water rushes down the street after a storm, it will often be heading straight for the river, along with the dirt and other materials it picked up off the road surface.

Markus Brinkmann is an Assistant Professor in the School of Environment and Sustainability with ties to the Global Water Futures program, the Global Institute for Water Security, and the Toxicology Centre at the University of Saskatchewan. He and his research colleagues have become well known for their work monitoring the levels of SARS-CoV-2 in municipal wastewater. They are also measuring and considering the impact of other substances in the wastewater and stormwater that end up in our rivers and lakes. We spoke with Markus to learn more about this topic.


Wastewater treatment plants have been designed to remove human waste from the water. This addresses the nutrient problem, but other chemicals aren’t as efficiently removed. In addition, there is significant variation in the type and capacity of wastewater systems currently in use. In some cases, there is an elaborate system set up to clean the water. In other systems, such as the septic tanks and fields on acreages and lakeside communities, there is huge potential for contaminating ground and surface water. Problems with toxic algal blooms are already being reported in the lakes of the Qu’Appelle Valley due to excess nutrients. Smaller communities rely on lagoons to settle the waste out of the water. “The lagoons have to be pumped out occasionally,” Markus says. “That’s when we see spikes in stuff like pharmaceuticals and microplastics that don’t degrade.”

Human and veterinary pharmaceuticals are specifically designed to be water soluble. They don’t bind to sludge so they go straight through wastewater treatment systems, either in their original form or as they’ve been modified by the body. “Pharmaceuticals are designed to have a biological effect,” Markus explains. “Anti-depressants affect the brain, while painkillers target pain receptors. Downstream, they can have a similar effect on fish and other aquatic creatures. Contraceptives can turn male fish into females, while anti-depressants make fish more timid.” The impact on downstream water users is not yet known.

Researchers aren’t yet sure how big a problem this could be as it very much depends on the quantity of water in the rivers and lakes that receive the treated wastewater. “There’s a big range,” Markus says. “Under a low flow, there is very little dilution and a possible problem.” In the summer of 2021, the South Saskatchewan River was at its lowest level ever with a flow of only 70 cubic metres per second in Saskatoon. Similarly, Regina’s treated wastewater is discharged into Wascana Creek. In the summer months when there is very little runoff, up to 90% of the stream is wastewater. The creek discharges directly into the Qu’Appelle River and subsequently Pasqua Lake.

Another big problem is the anti-microbials and preservatives that are added to household and personal care products. There are large quantities of anti-microbials and preservatives in hand sanitizers and laundry detergent, but you’ll also find them in shampoo, hand lotion, etc. (look for the number in a circle to find the product’s shelf life). “It makes sense to buy things that will last and won’t get moldy, but they’re pretty harsh products. They’re not degradable and get into our rivers to a significant extent,” Markus says. Very little is known at this time about their environmental impact.


Scientists have been studying stormwater for many years. The initial focus was on contaminants in tires and brake pads. Street sweeping and stormwater ponds addressed these materials and scientists hoped the issue was resolved. Unfortunately, that’s not the case.

Community groups in Pacific Northwest coastal cities have been investing time and money to restock salmon in urban waterways only to find the fish would die in large quantities following a rainstorm. While previous research had focused on heavy metals and hydrocarbons, scientists were now looking for a new compound, high concentrations of which have also been found in Saskatoon’s stormwater.

6PPD-quinone is an environmental transformation product of the anti-degradant and anti-oxidant 6PPD that has been added to tires to protect the rubber so it doesn’t become brittle, something that is particularly important in winter tires. Over time, the oxidation process turns 6PPD into something dangerous. “Manufacturers are struggling to replace this chemical, but it probably won’t be easy,” Markus says. In the meantime, researchers, such as those on Markus’ team are trying to determine how and if other species are affected and if  vulnerable stages in their life cycle line up with seasonal periods with more frequent rain and storms.

Socially Relevant Research

The work Markus and his team are doing has a direct impact on our lives. “There is a shift towards doing research that matters, that makes a difference in the here and now,” Markus says. “It’s hard to justify research funding for reports no one can understand. I’m still part of the research community and the output of papers and dollars count, but we’re paid by taxpayer dollars, and I don’t want to lose sight of that.” Markus believes this is even more important in the current anti-science environment. “We have to be held accountable,” he says.

Markus points to the Global Water Futures program at the University of Saskatchewan, which is heavily oriented toward putting research to use. The program’s stated goal is to “address the strategic needs of the Canadian economy in adapting to change and managing risks of uncertain water futures and extreme events. End-user needs will be our beacon and will drive strategy and shape our science.”

Another noteworthy program is Research Junction, a collaboration between the City of Saskatoon and the University of Saskatchewan. The research partnerships are driven by the municipality and are designed to address problems the city is currently facing. “It’s bringing all the stakeholders to the table so that we can co-develop solutions for issues cities can then fix,” Markus says.

For More Information

Tire Residue Chemical in Rain Runoff Kills Fish in Urban Streams

USask Research Finds Substance Derived from Tire Debris is Toxic to Two Trout Species

Plans Underway to Bring Salmon Back to Victoria’s Bowker Creek

Tire Preservative Found Responsible for Coho Salmon Deaths in Urban Streams

Fish on Valium: A Multitude of Prescription Drugs are Contaminating Florida’s Waterways and Marine Life

Poop: The Incredible Journey. It Starts With a Flush and Ends With a Fuel [Victoria’s sewage treatment process]

Photo credit: Carey Shaw, University of Saskatchewan