Wascana Creek, a narrow waterway that runs through Regina, has high levels of pollutants downstream from a sewage treatment plant and should be considered an ecosystem at risk, an Environment Canada study says.
High levels of phosphorus and trace levels of various pharmaceutical drugs are among the findings of the study published earlier this year. It was based on tests of creek water from 2005 to 2007.
"The Wascana Creek study highlights the considerable problems associated with excess nutrients in effluent-dominated ecosystems," the study says. "It also underlines the need for better controls on [ammonia] from sewage treatment plants."
The creek is home to carp and other fish, as well as various kinds of waterfowl. One issue identified is that in winter, 100 per cent of the creek flow west of the sewage plant is treated effluent.
"The findings were rather distressing," said Peter Leavitt, a water researcher at the University of Regina.
A city with a population of about 200,000, Regina has a modern, three-stage sewage treatment plant. It includes primary treatment, a five-cell lagoon system, alum treatment to remove phosphorus and disinfection with ultraviolent light.
However, the study, as well as experts like Leavitt, say that's not good enough.
Researchers sampled water at five locations along the creek. They found some nitrate levels within federal guildines for aquatic life, but others that were more than five times what's allowed.
Similarly, some ammonia levels were below the guidelines, but others were as much as 25 times over the limit.
Drug traces found in the water include dozens of substances, everything from caffeine to antibiotics.
"A lot of the problems that we've got right now have to do with just a very small water body and a high density of people," Leavitt said. "The city itself is not particularly large, but it's large relative to the type of river that it's sitting on."
The pollutants are also doing damage to other waterways downstream, especially in Pasqua Lake, which suffers from excessive algae blooms.
"The nutrient levels are higher than most every creek in the country and certainly the creeks in the Prairies," Leavitt said. "So why is Saskatchewan the worst in the country?"
Leavitt says Regina's waste treatment plant will need to be upgraded to filter out more of the pollutants.
City officials say their plant meets and exceeds stringent industry standards, but they are in fact planning a major upgrade.
The $150-million overhaul is in the works, with design work underway, and is set to be complete in five years.