Citizen science reveals salty findings

Every year countless tons of salt are spread on winter roads. Where does it go next? (Photo by Mike Schoonveld)

If you take a freshwater fish and drop it into the ocean it will die pretty darned quick. At least the vast majority of them will – as will many of the insects, plants, plankton and most other things adapted to life in unsalted water.

So it only seems logical that putting salt into a freshwater lake or stream could be debilitating to the flora and fauna living in it. No one would do that, would they? No one other than highway departments across most of the world in towns and cities that experiences winter weather.

Highways are safest when they are ice free so the rubber on the tires can meet the road, not a layer of ice or snow coating the surface of the road. Nothing deices roads better than chlorinated salts – sodium chloride, the most common salt found in the ocean and on the exterior of potato chips; magnesium chloride, used to make tofu, a micro nutrient in fertilizer and as a nutritional supplement. Calcium chloride is also used. All are bad and can contribute excess chlorine levels in freshwater.

Often, which salt used is related to it’s cost, since road departments buy it by the truck load. They also spread it on the road by the truck load and when the snow and ice melts and the rain pours down from the sky, all that salt goes somewhere. Much of that somewhere, especially in areas with storm drains with outflows to lakes or streams – or where roads run close to lakes or streams – is into those lakes and streams.

Regardless of which is used, high concentrations of these salts can be bad so the Izaak Walton League of America, last year, started a volunteer program to find out if road salt is a problem and if so, how widespread is it. Volunteers sign up to get kits to test local streams or lakes. An initial pre-snow and ice season test is taken to get a baseline reading, then periodic repeat tests are taken after melting and/or rain events and the results are compiled via a cell phone app.

The good news is most rural areas always tested at normal and safe levels. Urban areas, not so much. Many urban areas were okay but plenty of them showed spikes of high salt concentrations after salting/melting/rain events and others showed high salt levels, exceeding the maximum tolerable level for freshwater organisms on a continuing basis.

The salt testing program continues this season. Hopefully, as the results continue to pour in, they can alert highway departments in areas where problems are frequently found and encourage them to adjust their road salting efforts to keep the runoff into streams and lakes at acceptable levels.

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Categories: Michigan – Mike Schoonveld

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