Along with the snow and ice of Vermont’s winters comes another familiar sight: road salt. 

Sprinkled across sidewalks and roads across the state, salt is an integral part of maintaining safety during the cold months. However, safety for drivers and pedestrians can come at the expense of wildlife and infrastructure.

“The increase of salt into [Lake Champlain] causes increased salinity levels, which could be toxic to fish, amphibians and microscopic organisms that form the base of the food web,” said Lindsey Carlson, water and science program coordinator for the Lake Champlain Committee. 

Zooplankton, a foundational part of Lake Champlain’s food web, experience population decline in the face of salt runoff, according to an April 2024 Ecohydrology & Hydrobiology article on zooplankton hatching success. 

Many other species struggle to maintain healthy salt levels, a challenge that can lead to embryo mortality and developmental defects in populations of animals like salamanders and wood frogs, according to Carlson.

“On land, salt runoff changes soil chemistry which makes it harder for native plants to absorb nutrients, while allowing for salt-tolerant invasive species to spread,” Carlson said. 

Salt runoff damages city infrastructure as well, weakening roadways and sidewalks and accelerating rust buildup on metal pipes and bridges. This damage leads to high repair costs for local municipalities, according to Carlson. 

This damage has not gone unnoticed, said Lee Perry, division director for maintenance at the Burlington Public Works Department. 

“Living in the watershed area of Lake Champlain basin, we’re very cognizant of [salt pollution] so we are trying to reduce our salt usage,” Perry said. “I think we’re doing good managing our salt usage and our application rates across the fleet.”

The city often mixes salt with magnesium chloride and byproducts from beer brewing. The sugar content in the mixture allows the salt to clump and stick to the road rather than slide off, making the application more effective, Perry said. 

Furthermore, sodium chloride, the primary chemical component of road salt, only works at temperatures above 15 degrees. In the peak of winter, it is more effective to use an alternative like sand, according to a Missouri Department of Natural Resources article. 

In order to further reduce salt usage, certain areas of the city are prioritized, according to Perry. 

“For average snows, two to three inches, we’re just going to salt the main arterial roads in and out of Burlington,” Perry said. “You want to be able to get traffic flowing out of town, so everybody gets home safely.” 

Policies around salt usage are going through the Vermont State House. A bill, S.29, would provide legal protections to salt applicators that go through a certification program of best application practices, according to a Feb. 9 VTDigger article. 

UVM is in charge of its own salting policies. The school meets with representatives from Burlington and South Burlington and members of local environmental agencies every few years to assess proper procedures, said Perry.  

These meetings allow the cities, as well as UVM and local businesses, to test new procedures and collaborate, said Kris Stepenuck, professor of watershed science and policy in the Rubenstein School of Environment and Natural Resources and associate director at the Lake Champlain Sea Grant. 

“UVM tries hard to think about and take steps to reduce use of salt,” Stepenuck said. “[Students] can also say something if they see too much salt having been spread on a campus or community sidewalk, parking lot or road.”

The University produces its own training materials for custodial staff in the top five languages spoken by employees. This training outlines methods of improving application procedures and reducing salt usage, standardizing expectations for workers, said Stepenuck. 

“Municipalities, businesses and individuals, all can play a role in reducing unnecessary salt use while simultaneously keeping roads and sidewalks safe,” Carlson said. “It’s so common for people to just put down a lot of salt and think that is what melts the ice. You really only need to apply a thin layer.”

Reducing the environmental impact of salt overuse can start on an individual level, Carson said.

“Whether it’s reduction of your salt use, substitution of what you use as a de-icer, or things like that, you as an individual can play a part in reducing salt usage and positively impacting aquatic ecosystems,” Carlson said.