Water pollution is a scary word. All it tells us is that there is something in the water that’s not naturally there. The problem is that the word “pollution” is general and doesn’t tell you anything specific about what’s in the water or how it got there. Water pollution is easier to understand and prevent when we break it down into types.
There are two overall types of pollution: point source pollution and non-point source pollution. Point source pollution comes from a distinct source such as a discharge pipe. Non-point source pollution comes from diffuse sources including runoff and atmospheric deposition.
Since we could fill a whole newspaper issue with information on pollution, I will limit this article to the types of non-point source pollution that are common in runoff to our lakes and streams. These pollutants can be divided into categories: nutrients, oil and grease, bacteria, and toxic chemicals.
Nutrients are the most common impact to lakes in Minnesota. Nutrients come from fertilizers, detergents and soil and the most common are phosphorus and nitrogen. These nutrients wash off the land during spring thaw and rainstorms and end up running into our rivers and lakes. When in our lakes and rivers, they fuel plant and algae growth that can be undesirable for lake recreation.
Oil and grease come from boat motors and wash off roads and driveways into lakes and streams. Oil forms a film on top of the water that often shows rainbow colors. This oil interferes with the surface tension of the water. Insects such as water striders that skate along the top of the water rely on surface tension to stay afloat. When there is oil or soap at the top of the water, they sink and drown.
Bacteria enters our waters from animal and human feces. Sometimes after large rainstorms, swimming beaches close due to unsafe bacteria levels. Human sources of bacteria can be failing septic systems and outhouses. Animal sources of bacteria include pets, waterfowl and animal feedlots. What you can do is keep your septic system maintained and clean up after your pets.
Toxic chemicals include herbicides, pesticides, paint and solvents. These chemicals effect fish, frogs, insects and aquatic plants. These chemicals should not be poured into the storm sewers. Check your garage, many of us have chemicals just sitting around because we don’t know how to dispose of them. The Becker County Regional Household Hazardous Waste facility is available for disposal of many of these chemicals. Check their website for a list of acceptable items: http://www.co.becker.mn.us/dept/environmental_services/hhw.aspx.
To prevent these pollutants from running into our lakes and streams, be mindful of what you apply on your lawn, leave out in your yard and street, and how you dispose of chemicals.
You can also be proactive and construct areas for rainwater to collect in your yard and get filtered such as rain gardens and wetlands. A rain garden is a depression that contains native plants and shrubs designed to collect and filter rainwater. It is both beautiful and functional.
A buffer of plants along the shoreline of lakes and streams will also filter runoff and other nutrients that might otherwise reach your lake.