Many people and municipalities turn to road salt to de-ice wintry streets and sidewalks. Unfortunately, road salt poses serious environmental and water contamination risks. Just one teaspoon is enough to contaminate 5 gallons of water, making removal via reverse osmosis extremely expensive. Moreover, the health of humans, pets, wildlife, aquatic organisms, vegetation, soil and infrastructure are heavily impacted as road salts enter the environment, seeping into groundwater and draining via runoff into freshwater estuaries. At the forefront of advocating for better practices on road salt use is the Izaak Walton League’s Winter Salt Watch program.
Just last winter, the League dispensed 500 chloride test kits to volunteers across 17 states. Tests showed consistently high levels of chloride ions in waterways surrounding eight major metropolitan areas, signaling excessive misuse of road salts. This year, the League has sent out a batch of chloride test kits to more than 200 new volunteers.
“Our goal is to not only make residents aware of the impact road salt has on local streams but also give them the tools to advocate for changes to road salt practices that will decrease salt impacts while keeping roads safe for drivers,” explained Samantha Briggs, the League’s Clean Water Program Director.
Road salts are mainly comprised of sodium chloride, ferrocyanide (an anti-caking substance) and impurities like aluminum, cadmium, calcium, chromium, copper, iron, magnesium, manganese, nickel, phosphorus, potassium and zinc. All of these components are contaminants in water and exacerbate salinity levels.
What risks do they pose? The sodium chloride, for instance, breaks down into sodium (Na+) and chloride (Cl-) ions. Sodium in drinking water is unhealthy for individuals suffering from hypertension, or high blood pressure, which explains the EPA’s measure of monitoring sodium content in public water supplies.
Meanwhile, the American Society for the Prevention of Cruelty to Animals (ASPCA) has issued warnings regarding road salt ingestion and dangers to paw health of pets. Paw exposure to road salt exposure begets irritation, inflammation and cracking that leads to infection. When road salt is licked off paws or eaten, pets can exhibit vomiting, diarrhea, depression, disorientation, cardiac abnormalities, seizures, coma and even premature death.
As for wildlife impacts, once road salt enters a body of water, it is nearly impossible to remove. This adversely affects bird, amphibian, mammal, fish and aquatic plant populations. Road salt in the environment elevates both salinity stress and osmotic stress, which are associated with aberrant development, nutrient uptake degradation, toxicosis, weakened immune systems, low reproductive levels, population decline and mortality. When road salt damages vegetation, that creates losses in food resources, shelter and breeding sites.
Similarly, road salt’s presence accelerates infrastructure corrosion and structural integrity. Streets, highways and bridges are all subject to damage as road salt impairs asphalt and creates potholes. The corrosion extends to vehicles, as repeated salt exposure increases rusting and damage to critical vehicle components, according to the American Automobile Association (AAA). Even more worrisome, road salts damage water pipes, causing toxic metals, like lead or copper, to leach into drinking water.
To promote awareness and best practices regarding the hazards of de-icing, the Izaak Walton League has been pushing for “smarter ways” of using road salt, especially with “alternative approaches that include brine or sand application.” For those interested in volunteering as a stream monitor with the League’s Winter Salt Watch program to help gauge water quality and road salt risks, a free chloride test kit can be ordered here.
Image via Eddie Welker