As many of us have plans to travel on the roads during the next few weeks, a sustainability topic related to snow and cold seems appropriate. A common scene before a snow or ice event is the array of trucks lined up on the highways waiting to spread a layer of salt or some other de-icer on the roads. Then there are the times that you end up stuck behind one of these trucks with no way to get around it. Having lived in South Dakota and Minnesota for much of my life, I have witnessed these scenes many times. When my wife and I moved to California some years back, I remember the first time that I took our vehicle to a mechanic: he took one look underneath and said "You're from out east, aren't you?" Well out east meant anywhere east of the Rockies, and the rust on the underside of the vehicle due to road salt was all the evidence he needed.
Have you ever wondered about the extent of the environmental impacts caused by such large quantities of salt and other de-icing chemicals being used on the roads and sidewalks and if there are less environmentally-harmful alternatives that are just as effective? According to the Minnesota Stormwater Manual, approximately 365,000 tons of road salt is applied to roads within the Minneapolis/St. Paul Metro area alone annually; this number increases to over 730 million pounds if you include the entire state of Minnesota, not including parking lots, driveways, and sidewalks. Though the numbers may not be as extreme in the Washington, DC, Metro area, repeated application of road salt can still be detrimental to the surrounding environment. The most popular de-icer is rock salt because it is less expensive, easily obtained, and very effective. Table salt and baking soda are also popular household alternatives for sidewalks. The problem is that as the snow melts, the chloride they contain makes its way from the roads and sidewalks into nearby lakes, streams, and groundwater, where it can cause extensive environmental damage due to its toxicity to fish and other aquatic organisms and plants. Chloride, in particular, ends up being the biggest problem due to the fact that it is corrosive and very difficult to remove once it gets into the water.
So are there effective alternatives to using rock salt on roads and sidewalks? The answer is yes . Salt is by far the most effective solution as it can melt ice at temperatures as low as 15 degrees F; alternatives do tend to be less effective and more expensive. One alternative is to use one of various kinds of food byproducts, such as beet juice, pickle juice, or cheese brine. The major issue here is that the organic material they contain can deplete lakes and streams of much-needed oxygen, leaving fish and other aquatic life with too little to survive. Other materials such as sand and coffee grounds can be more effective and provide some traction on slippery surfaces, though they can clog sewers and cause sediment problems in nearby lakes and streams. If you prefer commercial de-icers, look for brands that are made from calcium magnesium acetate and/or are "chloride-free" and "pet safe" (de-icers containing chloride can burn dog and cat paws and are toxic when ingested after licking their paws). Examples include Snow Joe Melt2Go, Safe Paw, and North Pro Nature.
Prior to purchasing a de-icer, the first step I would recommend, especially if your house faces in a southerly direction, is to clear as much snow from the surface as possible. The fact that snow is white causes much of the radiation from the sun that could be used to melt the underlying ice to be reflected away from the ground; clearing snow reveals the darker ice or pavement underneath that can more easily absorb the sun's radiation and thus promote melting. Adding a little sand or coffee grounds to the icy parts of your sidewalk or driveway after removing the snow will also make the area appear darker and thus have the same effect, though you should remember to sweep it up later to avoid the issues mentioned above. Finally, investing in some cleats that can be worn over your shoes may be a good idea, though, depending on where you live, they may not get much use throughout the year.
Helpful Hint
When clearing snow or ice from your driveway or sidewalk, first try using sand or coffee grounds to promote melting. If a commercial de-icer is required, try using one of the "chloride-free" brands mentioned above. Feel free to add a comment regarding its effectiveness or to suggest another effective and environmentally-friendly brand or alternative.
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