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It’s a nutrient, it’s a deicer, it’s polluting our environment.

It’s a nutrient, it’s a deicer, it’s polluting our environment.

Salt from deicing roads gets into lakes and rivers

Winter is over… Or at least according to the calendar
Yet, I awoke to flurries in Cambridge, Massachusetts just a few days ago. These flurries turned into full-fledged snowfall by the time I got to work. Really? It was April 2nd. The good thing was that hopefully the city did not see the need to salt the roads heavily because it was going to be warm enough to prevent ice patches from forming.

Of course, salting roads is beneficial because it prevents the formation of ice patches on roads and sidewalks, thus, making it safer for commuting motorists, cyclists, and pedestrians. However, excess salt can take a toll on the environment, and application of salt on the roads and sidewalks is not always done with the health of our surrounding ecosystems in mind. In some cases, salt is dumped unevenly or in patches which may end up sitting in the road for weeks. But just like when we add salt to pasta water and watch it disappear as it dissolves, road salt dissolves into rain or melting snow and flows with this water into nearby streams and lakes.

How much salty are our waters, really?
A recent study titled Salting our Freshwater Lakes, investigated how the practice of road salting is contributing to high salt levels in urban lakes. The study focused on the Midwest and Northeast regions of the United States, where there are dense road networks near freshwater lakes. Since paved surfaces comprise more than 1% of the area close to the shores of nearly one third of the lakes in the United States, road salting can have serious impacts on water quality. Salt, whether it is the kind you use for your pasta or to de-ice the road, contains chloride. In this study, the authors investigated the chloride concentrations in 284 freshwater lakes in North America that had at least 1% of paved surface nearby.A staggering 70% of the lakes investigated had elevated concentrations of chloride, likely due to road salting.Extrapolated to include all lakes in the study region (CT, MA, ME, MI, MN, NH, NY, RI, VT, and WI), this could include as many as ∼7,770 lakes!