The ripple effect of salt in our water

Last week, I touched on the growing problem of chloride (salt) pollution in our waterways, and steps that we can all take to help slow the increase of this substance. This time, we are going to dive a little deeper into the trauma that salt pollution has on a natural landscape and why this is important.

Before anything else, I want to mention again that chloride is a permanent pollutant in water. Yes, we can purify and remove contaminants. But by no means can we do so to treat all the water in the state (more specifically, we couldn’t dream to fund such a colossal feat). So for all practical purposes, it’s permanent and is here to stay.

Which brings me to another point: chloride-rich water isn’t washing downstream like we might assume. I believe that seeing the mammoth-sized flows of water running through our rivers gives the impression that water is leaving our localities, but this really isn’t the case: a five-year study by the University of Minnesota on the input and discharge of chloride within the watersheds of the metro found that more than 75 percent remained in the area.

In other words, the salty water gets held up in soils, surface waters (ponds, lakes, wetlands), and groundwater.

So it’s clear that chloride hangs around for a long time, but what does that mean in terms of environmental effects?

To put it plainly, salty water doesn’t mix with the critters native to our waterways. Consider it as you would air pollution: in small doses the concern is mostly centered on at-risk populations, and increasing concentrations expand the scale of damage. In this case, our at-risk populations are macro-invertebrates (bugs) who face both an inability to breed and rapid juvenile die-off.

Remember that tidbit from my last column about it taking only 1 teaspoon to pollute 5 gallons of water? That relates to these bugs (among other organisms) who can’t tolerate those water conditions.

The broader impact? Aquatic bug population die-off triggers a cascading effect through the food chain. The fish that eat those bugs just received a calorie-restricted diet. This means that fish that eat those fish are at an even greater loss, and now those of us who fish really get the short end of the stick, as there are fewer big fish to catch! (Darn diets ….)

And as with air pollution, salted water means poorer living conditions, including difficulty breathing, diminished development of young, disrupted or changed community structures, weakened immunity and health, and so forth.

So all of this impairs not only the recreational qualities of waterways, but also the natural role waterways play in the ecological continuum.

And this is not the sole problem from chloride, but rather just a magnified portion. See more at the Minnesota Pollution Control Agency website, pca.state.mn.us, for a better grasp on what is happening because salt is entering our waters.

Writer Chris Gass is a Minnesota GreenCorps member with the Carlton Soil and Water Conservation District whose bi-monthly columns will focus on environmental topics and stewardship, particularly in cities and towns.