The impact of road salt on our environment

The impact of road salt on our environment

By Ted Butler

Road salt is an important tool currently being used in the annual battle to keep our roads safe during our cold Canadian months. Many Canadian municipalities use road salts (and other chemicals) on our streets and sidewalks for their deicing and/or anti-icing capabilities.

The question is, do we use too much salt and chemicals on our roads? Are they having a negative impact on our environment, and do they contaminate our streams and rivers?

To answer these questions, let’s have a look at two of the most popular de-icing formulas being used today…

Sodium Chloride - NaCl.

Commonly known as salt, sodium chloride is an ionic compound with the chemical formula of NaCl. Sodium chloride is mostly responsible for the salinity of seawater. Large quantities of sodium chloride are also used in many industrial processes and NaCl is already being detected in our ground water. The measured amounts of NaCl is expected to increase over time which will eventually contaminate drinking water.

Many Canadian municipalities use road salts (and other chemicals) on our streets and sidewalks for their de-icing and/or anti-icing capabilities.

Salt also completely loses its effectiveness as a de-icing agent when the ambient temperature reaches -13 to -15 degrees Celsius. Other de-icing sprays can lose their effectiveness at temperatures between -7 or -9 degrees Celsius, which means applying them to the roads below these temperatures is futile.

Magnesium chloride (MgCl 2 )

Magnesium chloride is the name of a chemical compound, the formula MgCl 2 and its various hydrates MgCl 2 (H 2 O) x . These salts are typical ionic halides which are highly soluble in water. Hydrated magnesium chloride can be extracted from seawater. Some magnesium chloride is made from the solar evaporation of seawater. Hydrated magnesium chloride is the form most readily available. Chloride (Cl-) and magnesium (Mg+ 2 ) are both essential nutrients important for normal plant growth, but too much of either nutrient may harm a plant. High concentrations of MgCl 2 ions in the soil may be toxic or change water relationships and the plant cannot easily accumulate water and nutrients. Once inside the plant, chloride moves through the internal water-conducting system and can lead to the death of the plant.

Possible environmentally friendly solutions

Cheese Brine Some roads in Wisconsin are treated with cheese brine from local dairy companies. The salt baths which are used in making cheeses like mozzarella or provolone need to be discarded as a waste product, and it costs money to have it treated off site. The dairies dispose it for free and the county acquires it for free – a win-win, according to authorities.

Beet Wastewater This is an organic-based liquid that contains processed beet molasses. It’s been used by over 200 agencies in the USA. When it’s combined with the traditional de-icing agent of salt, the beet product freezes at a lower temperature than a pure salt brine so it can be used in lower temperatures.

Pickle Juice Pickle brine is as effective as salt. It can melt ice at temperatures as low as -6°F or -21°C. It doesn’t smell great, but it’s cheaper and deposits less chloride into the environment than salt and there's plenty of it being discarded in homes and factories.

Barley Residue

Alaska has applied leftover barley residue from vodka distilleries to melt ice on its roads. Russia, Hungary, and Tennessee have used waste from the distilleries.

It seems many regions may have found alternative chemicals on hand that can be inventively used to cut costs, eliminate waste, and protect wildlife, water, and humans from the harm that is accumulating. Sometimes the most creative environmental solutions can come from the most unusual origins. Maybe it’s time for big change. ■

Ted Butler is the corporate sales director of Canada Heavy Equipment College.