By Patricia Houser
For Nature’s Sake
Patricia Houser
Experts agree that salt de-icers can reduce accidents by 78 percent or more on icy roads. The problem – and it’s a big problem – is that we have been using way too much of it.
Applying too much road salt not only doesn’t make streets safer – it poses a risk to the long-term availability (and affordability) of clean drinking water while threatening the survival of a chain of living things in our landscapes and waterways.
Approximately 70 percent of the US population lives in states where winter requires de-icing strategies for travel safety. In those states the use of road salts has tripled over the past 45 years. That trend has been accompanied by a “substantial increase” in salt concentrations in streams, rivers, lakes and other sources of freshwater, according to leading scholars in a recent issue of Frontiers in Ecology and the Environment.
For some, the downside of road salt is associated with walking a canine companion on a winter day. Anyone who’s seen fido limping in pain after stepping on salt shards doesn’t soon forget it (Brookfield Animal Hospital’s website has tips for paw burns).
Others are focused on the need for extra car washes to rinse corrosive salt off the underside of a car or truck. According to a AAA survey from 2017, the extra rust caused by road de-icing materials costs US drivers an estimated $3 billion each year.
On a larger scale, the chloride in excess road salt leaches the calcium out of concrete in bridges and roads. It also corrodes steel rebar, leaving damage that can undermine the structural integrity of roads and bridges.
The salt tossed on our streets and sidewalks and parking lots doesn’t just disappear at the end of winter. Some splashes onto vehicles. Some eats away at bridges and concrete. Most damaging of all, a certain amount every year makes its way into storm sewers, streams, lakes and the soils at the road’s edge, impacting plants and animals as much as 500 feet from the road.
In Connecticut, chloride levels in streams around the state roughly doubled between 2000 and 2015, according to Chris Bellucci, the monitoring group supervisor from the state Department of Energy and Environmental Protection’s Bureau of Water Protection and Land Reuse. That is, between 2000 and 2005, the median chloride level for streams, based on testing sites around the state, was 15 milligrams per liter, while from 2011 to 2015 it was 30 milligrams per liter.
While no one wants that trend to continue, Bellucci emphasizes that the overall levels for most streams in the state are still well below the chronic exposure guideline of 230 milligrams per liter for aquatic safety set by the EPA in the late 1980s.
Those rising salt concentrations, even at sub-lethal levels, are taking a toll on wildlife around the state, from zooplankton and butterflies to frogs, salamanders and fish. Jenny Dickson, director of the Wildlife Division at DEEP, says chronic high salinity in aquatic environments is an additional “stressor” to plants and animals already confronting chemical and mineral contaminants from various land uses.
That extra stress, Dickson explains, translates into organisms literally getting sick with various viruses and fungi. She gave the example of what is happening to dragonflies: “If you’re thinking about things like dragonflies in some of the larval stages [a rise in salinity] has really reduced their immune response and makes them more susceptible to parasites. And you might say ‘Well, why does that really matter?’ But larval dragon flies are actually a huge aquatic predator – they eat all kinds of things including mosquito larvae. So there are some direct benefits to us in making sure there are still some dragonfly larvae swimming around in some of those little pools and ponds.”
The road salt on our landscapes has reached even closer to home, in our drinking water. When John Hudak, the environmental planning manager for the Regional Water Authority, was interviewed for this column last summer, he mentioned rising salt levels at the source of Milford and Orange’s water supply. Like so many other environmental managers, Hudak supports the use of Green Snow Pro training (which reduces the amount of salt used while preserving safety) for companies and towns.
State Rep. Jamie Foster of East Windsor, who is also a PhD researcher with an expertise in nutrition and public health, says that the excessive salt in drinking water, “when we already have a diet that is exceeding our daily salt recommendation, is really dangerous for your heart health.”
Foster, along with state Sen. Saud Anwar of South Windsor and state Sen. Christine Cohen of Guilford, all promoted a bill last year that included new protections against salt in drinking water and that would provide relief for those whose well water is contaminated by excessive salt use. That bill didn’t get past the Appropriations Committee; however, a new version seems likely to replace it this year.
Veronica Tanquay, a DEEP environmental analyst, says that another issue is chloride. That’s the substance that degrades steel bar and concrete, and it can also corrode the lead solder and copper pipes in peoples’ homes. It even draws manganese and other minerals out of the bedrock to further contaminate well water. Tanquay notes that chloride from road salt was part of the pollution in the Flint River in Michigan that contributed to the Flint lead poisoning crisis beginning in 2014.
These experts and others have a few recommendations for the average person. First, if you rely on well water, have it checked once a year using the state Department of Public Health’s online pdf titled, “Publication No. 24: Private Well Testing.” Second, consider volunteering to test local streams for salt using the Isaac Walton Winter Snow Watch kit available online. Third, learn about how to reduce your own salt use in winter. For example, the Minnesota CBS mini tutorial “Good question: How much sidewalk salt should we use?” is available on YouTube. Fourth, let your local legislators know if you are ready to support road salt legislation that helps us use salt more wisely statewide.
Finally, thank the local officials who manage our roadways. In both Milford and Orange the highway departments and departments of public works have made an impressive start on reducing excess road salt.
Patricia Houser, PhD, AICP, shares her exploration of local and regional environmental issues in this column as a member of the nonpartisan Milford Environmental Concerns Coalition.
“Experts agree that salt de-icers can reduce accidents by 78 percent or more on icy roads.”
This statement is not exactly factually correct though often cited. It is received wisdom extrapolated from a study sponsored 30 years ago by the now defunct salt industry trade group The Salt Institute. The data of the study also relies on a German study from the early 1980s of limited scope that found that road salt benefits were of short duration and largely derived from modeling rather than real time real world data.
Neither of these studies looked at other alternatives like reduced speeds and the use of winter bias all season tires and / or winter tires that both meet the “3 Peak Mountain Snow Flake” (3PMSF) severe snow service standard that now exists and are required by law in many countries and states, including Germany and Utah and Quebec for example.
Can you recommend a particular scholarly work (or source) that further explains what you are pointing to as limitations in existing research? I’d like to know more.
For my statement on the effectiveness of road salt as a safety measure I relied on the judgement of leading scientists in state and federal government. Most recently, the 2022 study with Bill Hintz (from Univ. of Toledo, Ohio) as lead author, stated it this way: “Road deicing salts are applied in these cold regions to protect the traveling public because they reduce vehicular accident rates by 78 – 87% (Kuemmel and Hanibali, 1992; Mulaney et, al., 2009; Useman et al, 2010).”