Road Salts

Photo: Brendan Wiltse

Deicing salts applied to road surfaces during the winter contain chloride, which can be transported to Lake Champlain throughout the year by snowmelt or rain runoff and by groundwater inputs to rivers and streams. This makes rivers and lakes saltier, a process known as salinization.

Human-caused salinization of freshwater systems has been found throughout the Lake Champlain region and the world. Negative effects of salinization can impact all levels of an ecosystem, including plants and algae, zooplankton, macroinvertebrates, amphibians, and fish communities.

Although chloride concentrations found in Lake Champlain remain well below established benchmark levels for drinking water and aquatic life toxicity (250 and 230 milligrams per liter, respectively), chloride concentration in the Lake is increasing. This increase is driven by long-term increasing trends of chloride loading from nearly all Lake Champlain Basin rivers.

Water Quality and Ecosystem Impacts

Road salt eventually washes off roads, parking lots, driveways, and sidewalks. It may seep into the ground or flow into nearby waterbodies. Over time, chloride can accumulate in groundwater, lakes, and ponds and affect drinking water, water quality, and ecosystem functioning.

Water polluted by road salt is denser than freshwater, meaning it will settle in the deepest parts of the lake. Researchers on New York’s Mirror Lake observed significant salt accumulation at the bottom of the lake, where it had begun to block an important lake mixing process that distributes oxygen and nutrients throughout the water column. When deep waters become deficient in oxygen (a condition called hypoxia), they become uninhabitable to fish and other aquatic species.

Most aquatic species in the Lake Champlain Basin cannot tolerate excessively salty conditions. Zooplankton, which form the base of the aquatic food web, can handle varying levels of salinization but generally require freshwater to hatch their eggs. Amphibians are also vulnerable to salt, as they absorb pollutants through their skin. This can lead to dehydration and hinder amphibians’ ability to regulate their water balance. In some species, like the wood frog, exposure to road salt pollution can alter the male to female ratio, putting long-term reproductive rates at risk.

Fish that spawn in Lake Champlain’s tributary rivers and streams can also be affected by salty conditions, which reduce the availability of suitable habitat.

Humans can also be impacted by road salt pollution. In rural areas, road salt can seep into private wells and increase the salinity of drinking water.

Protecting Property and Infrastructure

When applied in large quantities over long periods of time, road salt has a corrosive effect that damages cars, trucks, bridges, and roads. The United States Environmental Protection Agency estimates that approximately $5 billion dollars are spent annually on managing these impacts.

Road salt can also damage drinking water infrastructure, exposing communities to contaminated drinking water.

Road Salt Reduction Efforts

To reduce chloride levels in Lake Champlain and its tributaries, the LCBP, resource managers, and public works departments across the Basin are conducting research and taking initiatives to safely reduce winter deicing salt application and to educate individuals and property managers on best deicing practices to reduce impact to Lake Champlain and other waterbodies.

What You Can Do

Follow these tips to reduce your salt use at home and work:

Shovel First

Clear snow and ice before applying salt. The less there is to melt, the less salt you’ll need.

Check the Temperature

Salt doesn’t work well below 15 degrees Fahrenheit. Use sand to create traction when the temperature is too low.

Spread Lightly and Evenly

Not every surface needs salt. Apply salt where it’s needed most, such as walkways, steep driveways, and steps.

Spread salt with grains about 3 inches apart. Use no more than one cup for every two parking spaces or 10 sidewalk squares.

Sweep

If salt and sand remain on the ground after ice has melted, sweep it up to reuse in a future storm.

Learn more about road salts and chloride

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