Whether you love it or could leave it, winter is coming. And with changing weather comes icy roads, sidewalks, parking lots and driveways.
To keep pedestrians and drivers safe, municipalities, businesses and homeowners apply salt or sodium chloride, to these icy surfaces. Salt works well to melt snow and ice, but did you know it’s toxic to fish and other aquatic life?
Once it washes off roads and other surfaces, salt eventually ends up in nearby streams or in groundwater. We measure the amount of salt in the environment by tracking levels of chloride. In recent decades we’ve seen chloride levels increasing in streams across the Credit River Watershed.
Stream chloride levels peak in the winter, sometimes reaching as high as 25 times the amount that is safe for aquatic life. Some of our groundwater monitoring wells also have high levels of chloride.
Besides being toxic to fish, aquatic insects and frogs, chloride is also harmful to wetland plants. Sensitive plants may get replaced by salt-tolerant ones, reducing wetland biodiversity.
While road salt is the biggest source of chloride in the watershed, there are other ways chloride gets into the environment. Dust suppressants on gravel roads and some fertilizers also contain chloride. Water softeners release salt that eventually ends up passing through a wastewater treatment plant or septic system. But unfortunately, salt doesn’t get removed in the process.
We can all play a role in reducing the amount of chloride that goes into the environment. Learn more about chloride levels in the watershed and how you can help protect our streams and groundwater – check out our Integrated Watershed Monitoring Program StoryMap Collection.
You can also view chloride levels across the watershed in real-time. Share your thoughts with us on LinkedIn.
By: Adrienne Ockenden, Specialist, Watershed Monitoring