Gass column: Want water pollution? Just add salt
Not long ago, 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 this has on a natural landscape and hopefully further relate why this is important.
Before anything else, I want to mention again because it is always worth reiterating: Chloride is a permanent pollutant in water. Yes, we can purify out contaminants. But by no means can we do this to treat all the water in the state. (More specifically, read: We couldn't dream to fund such a colossal feat).
So, for all practical purposes, it's permanent and is here to stay, which in fact brings me to another point: Chloride-rich water isn't washing down stream like we might assume. I believe 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.
For reference, a five-year study by the University of Minnesota reviewed the input and discharge of chloride within the watersheds of the metro, and in turn found that over 75 percent remained in the area. In other words, the salty water gets held up in soils, surface waters (ponds, lakes, wetlands) and groundwater.
All right, so it's clear that chloride hangs around for a long time, but what does that mean in terms of environmental effects? Well, to put it plainly, salty water doesn't mix with the critters native to our waterways. Consider it like 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), which face an inability to breed and rapid juvenile die off under moderate amounts of salt.
Remember that tidbit of my last column saying, "1 teaspoon of salt pollutes 5 gallons of water?" That measurement relates to these bugs (among other organisms) who can't tolerate those water conditions.
The broader impact? Aquatic bug population die-off means a cascading effect through the food chain. Whatever the bugs did eat are now at their leisure and the fish that were eating the bugs just received a calorie-restricted diet. This means the fish that eat those fish are at an even greater loss and now those of us who fish really get the short stick as there are less big fish to catch! (Darn diets ...)
Not to mention, as like air pollution, salted water means poorer living conditions — harder time to breathe; diminished development of young, disrupted or changed community structures; weakened immunity and health; and so forth.
All of this in turn serves to reduce not only recreation of a waterway, but also the natural services it provides in the ecological continuum.
By no means think of this as the one trouble from chloride, but instead just a magnified portion. Know that more detailed information can always be found through the Minnesota Pollution Control Agency website, which also showcases the wider effects.
Chris Gass is a MN GreenCorps member serving at the Carlton Soil and Water Conservation District and focusing on stormwater and urban forestry. Reach him at 218-384-3891 ext. 5. Information on the SWCD can be found on Facebook and at carltonswcd.org.