The use of road salt during the winter has become a common practice in Connecticut in order to keep roads open, but this may be sacrificing the quality of important water resources for quick road access. Road salts have contaminated public and private drinking water across Connecticut, but experts say that the public is generally unaware of its effects.

The harmful impacts of road salt have come to light in recent years. According to a 2018 article by Allison Dunne, research on private well water quality conducted from 2007-2013 in New York found that more than half of the private wells tested had levels of sodium higher than the guidance levels set by the Environmental Protection Agency (EPA). The EPA recommends drinking water contain no more than 20 milligrams per liter. The public has remained generally unaware of this issue according to Michael Dietz, a hydrologist who heads the Department of Natural Resources and the Environment at the University of Connecticut.

Effects of contaminated water

Road salt dissolves into melted snow and the resulting runoff ends up in surface water, such as streams and rivers. As it travels down through soil, the salt contaminates groundwater as well. This impacts vegetation, aquatic life, and public and private drinking water, Dietz said. 

According to the EPA’s website, “Road salt can contaminate drinking water, kill or endanger wildlife, increase soil erosion, and damage private and public property. Alternative methods are needed to mitigate these drawbacks.” One component of road salt is sodium chloride, which can have harmful effects on infrastructures. 

“Chloride is not going to cause cancer, the sodium can be problematic for people on sodium-restricted diets and that sort of thing, so it’s not necessarily going to kill you if it’s a little high,” Dietz said. “The problem with chloride is it can cause other things to leach out from your piping system, like metals. For example, lead. It can corrode the pipes itself, so that’s a reason chloride is a concern,” Dietz said.

The EPA Recommends that private well owners test their wells annually to ensure they are not contaminated with toxic chemicals. According to their website, the EPA recommends testing a private well if there is significant change in water quality, or changes with the environment of a well.

A 2023 report on private residential wells by the Connecticut Institute of Water reported that out of the 102 wells tested across the northern half of Connecticut, half of the homes’ wells had exceeded the standard level of coliform, a bacteria that lives in warm blooded organisms, set by the Connecticut Department of Public Health. These numbers are discouraging, given that 820,000 residents relied on well water in the state according to the 2010 census report. When found in wells, coliform is a sign that there could be pathogen contamination, which could indicate a contamination from road salts.

Several public water supply wells in Connecticut are also contaminated by road salt. The Connecticut Department of Public Health (DPH), is in charge of regulating public wells. According to Dietz, water companies and the DPH are both very much aware of the issue. Unfortunately, there is less information on public wells available to the public. 

Where is the salt going?

Road salt can be flushed out of soil and natural water sources, but not always in a timely manner. According to Dietz, water that moves slowly through soil will flush out contaminants more slowly than water that moves quickly. Dietz said that rainfall helps flush road salt contaminants out of our environment as well. However, recent droughts make rain an unreliable source of relief.

With large amounts of road salts applied each winter, it could take anywhere from months, years, decades, and possibly centuries to flush out all of the saline in groundwater according to Ashley Helton, researcher and associate professor for UConn’s Center for Environmental Sciences & Engineering.

“Road salts come in the winter when there is not a lot of biological activity, so the idea is that the snow melts and the big spring storms will flush it downstream to salty systems, so it doesn’t matter,” Helton said. “Here we are and the systems are salty in the summer, so what happens is road salts that don’t get flushed away seep into the soil. Salt does not bind very well with soil so it just percolates right into the groundwater and then we have salty ground water,” Helton said.

Road salt runoff either moves downhill or flushes into groundwater, both of which could end up in natural bodies of water. This negatively impacts organisms in these bodies of water that have evolved to survive in freshwater. Too much salinity can harm a variety of aquatic organisms such as fish, salamanders, and microbes, according to Ashley Helton. This can also disrupt the food chain as well as ecosystem function.

When testing the salinity of Eagleville Brooke at UConn, Helton said they found that the water was brackish in the summer, meaning the system is partially fresh water and partially salty. This was unusual because Eagleville Brooke is a fresh water system. According to Helton, this has happened to freshwater systems across the state of Connecticut as a result of road salt runoff. Researchers are currently questioning how much salinity these organisms can withstand and how much they are affected by road salt, Helton said. 

Road salt is generally applied in a wasteful manner, Dietz said. Road salt stops water from freezing at temperatures of 32 F (freezing point of water) and below, but when temperatures reach around 10 F, the effectiveness of road salt slows down. Regardless of how much road salt is applied, it will runoff and cause harm downstream. 

Action on UConn’s campus

Green Snow Pro, a program started at the University of Connecticut in 2018 and run by the CT Training and Technical Assistance Center has received state funding to expand and train municipalities throughout the state. The program was adapted from the Green Snow Pro program in New Hampshire that trains people who apply road salt, such as contractors and public work staff. The program teaches workers how to apply road salt more efficiently based on weather and the conditions of the road, according to Dietz, who has attended training sessions.

A major conflict arises since Connecticut utilizes road salt to maintain safe driving conditions during the winter season. Road salt use is the most efficient way to maintain safe driving conditions according to Dietz.

It may be crucial that the public stay patient with issues like this. As Dietz emphasized, the public is generally unaware of the severity of this issue. Dietz also emphasized the importance of understanding the Connecticut Department of Transportation’s (DOT) obligation to clear the roads of snow in a timely manner, so people can drive safely. “The DOT has to deal with people,” Dietz said. When snow falls people call the DOT regularly, so it’s important to understand the complexity of solving the issue. The DOT was also a partner on the Green Snow Pro project when it was started, according to Dietz. 

“DOT is really good. They try to have the best equipment [and] the best technology they can to most efficiently apply [salt],” Dietz said. “They are very aware of this program [Green Snow Pro], you have to think about the quantity of salt they apply across the entire state, so it’s in their best interest to do it efficiently,” said Dietz.

According to Helton there has been research done on wetland vegetation and the remediation of road salt pollution by restoration and plant ecologist Beth Lawrence. Plants can take up salts, so by planting vegetation like cattail’s (Typha) along roadsides, the amount of road salt that enters groundwater can possibly be reduced. Although it seems like a good tactic, in the article “Plants As a Tool for Roadside Contaminant Removal” written by Elaina Hancock and published to UConn Today on September 21, 2023, Lawrence said that the process of removing the biomass takes a lot of energy. Although research is being done, efficiently placing road salt is still the most feasible way to reduce this problem.

“It’s tough doing this work in extension where you’re trying to solve a problem, you’re trying to address a problem, it involves behavior change in one form or another,” Dietz said. “It’s very frustrating when you know what needs to happen, but people either don’t want to know, or just haven’t got the message and aren’t changing their behavior.”