Not just for margaritas

Salt may prevent slipping hazards, but it causes environmental ones

A sprinkling of rock salt may keep you from slipping, but its accummulation may damage the environment.

A sprinkling of rock salt may keep you from slipping, but its accummulation may damage the environment.

Photo by David Robert

It’s that time of year again. Colder temperatures, fewer daylight hours, snow storms—and salt on the roads. Everywhere you turn, salt on the sidewalk, salt in the parking lot, and salt on the steps to your bank. Ten million tons of it in the United States every year, according to the University of Maryland. It makes things less slippery, but there are side effects.

Most salt used for deicing (that’s de-icing) is sodium chloride, or rock salt. Other options include calcium chloride, potassium chloride, magnesium chloride, and calcium magnesium acetate. They all work by reducing the freezing/melting point of water so that it evaporates in colder temperatures. The dissolving process goes like this: The ice immediately around the salt granules melts, and the melting spreads out from there. It’s cool, really, but the use of chemical deicers causes a few problems in the environment.

Salts can damage driveways, walkways and patios. Brick is especially susceptible, and even Cargill, a major producer of deicing compounds, recommends against using them on brick surfaces. Same with porous concrete, improperly cured or sealed concrete, and concrete less than a year old. They also caution against getting salt deicers on wood surfaces or carpets, so be careful about tracking salt inside.

Salt is corrosive to aluminum and steel, as well, so be careful to rinse off your car after traveling on salted roads.

Chemical deicers are also bad for waterways. The salt that gets washed off highways and down storm drains ends up in the Truckee River, ultimately polluting Pyramid Lake. The few handfuls of rock salt thrown on your sidewalk might not seem like a big deal, but remember the 10 million tons that everyone else is using. Those dissolved solids are definitely not fish-friendly.

The salt that doesn’t get washed away ends up in your yard or soil. Salts can damage plants in two ways: First, by direct contact with snowmelt, which can cause bud death and twig dieback. In evergreens, needles will turn yellow or brown. Second, repeated applications of salt compounds result in buildup in adjacent soil, causing damage to plant roots. Symptoms include wilting, abnormal cast, leaf burn and stunted growth. Look for these effects alongside the road next time you’re driving across Donner Summit.

And salt can cause problems for your pet. Dr. Mark Ditsworth of Kings Row Pet Hospital says it doesn’t happen very often, but he sees occasional cases of dogs with nasty irritations on their paw pads from walking through salt crystals, or gastrointestinal problems after they’ve licked salt off their paws: “It’s usually a local irritation, where you just need to flush their pads with clean water or a mild GI upset, where they’ll be throwing up.” He also had one instance of a dog burning the end of his tongue after licking salt.

The best solution to your snowy sidewalk or dicey driveway might be a little elbow grease and a handful of sand. Shovel early and often to remove snow, and add sand for traction if it starts to freeze up. If you do use salt compounds, follow the directions on the package, and use it sparingly. Be sure to check weather conditions before applying, as some chemicals work better in colder temperatures, and some don’t work at all below 20 degrees.