Waterloo Biology Professor Mark Servos’ research into the Grand River rainbow darter revealed the males once exhibited one of the world's highest incidence of intersex changes, with early stage eggs found in male testes.
His findings were highlighted this month in the Globe and Mail’s series Headwaters: The future of our most critical resource as part of the ongoing international effort to clean up the Great Lakes’ watershed.
Like “canaries in the coal mine”, male rainbow darters turn out to be extremely sensitive to estrogen and other contaminants being released into aquatic environments from municipal wastewater treatment plants.
Servos and his research group demonstrated that when Waterloo Region upgraded their Kitchener Wastewater Treatment Plant two years ago, the intersex occurrence declined dramatically. The investment by the local municipality is already showing signs of improving the conditions in the river.
Although we are making progress, Servos said in the article, he cautioned that we cannot become complacent when it comes to the health of the Great Lakes watershed.
There is no doubt that we have made progress in water management; things are way better than they were 30 years ago,” said Servos, Canada Research Chair in water-quality protection. “But the consequences of not continuing to be vigilant and prioritising water protection will be negative impacts on the health and prosperity of our communities.”
The importance of the Great Lakes cannot be underestimated. It’s the largest freshwater system on the planet; it provides drinking water to 44 million people; it’s home to a $7 billion fishing industry; and it serves as the shipping mega-highway from the continental Midwest to the St. Lawrence and the Atlantic.
Thirty years ago the health of the Great Lakes suffered serious setbacks from algal blooms and elevated concentrations of pollutants such as polychlorinated bipbenyl and dioxinss.
But now it faces a new series of threats ranging from continually increasing concentrations of nutrients (e.g., phosphorus and nitrogen), warming of lake waters, and the ubiquitous appearance of pharmaceuticals, microplastics and nanoparticles in waterways and beaches.
Servos is a member of the Water Institute. Also pictured in the story were Servos's graduate students Meghan Fuzzen, Keegan Hicks and Maricor Arlos, all PhD candidates within the Department of Biology.