BALTIMORE (January 14, 2022) – As winter weather impacts the state, Maryland continues to work to reduce the use of ice-melting salts that can threaten public health and the environment – including the water that we drink – while keeping traffic moving safely.
The Maryland Department of the Environment (MDE) is taking steps to reduce salt in rivers, streams, and groundwater to protect aquatic life and drinking water sources while roads are made safe for winter travel. MDE has been working for several years with state agencies and local jurisdictions on best practices for salt application, including use of improved weather forecasting, using the right amount of salt, targeting roads in most need of treatment, using brine to reduce overall salt usage, and increasing training for employees and contracted equipment operators. The Maryland Department of Transportation State Highway Administration (MDOT SHA) employs a range of strategies to reduce its use of salt while continuing to keep roads safe – and over the past five years has significantly reduced its overall salt usage up to one-half.
“The Maryland Department of the Environment congratulates and thanks to the Maryland Department of Transportation for leading by example when it comes to reducing the use of road salts that can threaten public health and our environment,” said Maryland Environment Secretary Ben Grumbles. “This winter, we urge all Marylanders to make smart decisions on the use of de-icing chemicals to help protect waterways and wildlife without ever compromising public safety or mobility.”
“MDOT SHA follows best practices in terms of using less salt while maintaining safe roadways for our customers,” said MDOT SHA Administrator Tim Smith. “MDOT SHA and our contractors work together as partners to reduce overall salt use while keeping safety as our highest priority.”
Clearing roads and highways of ice and snow help to ensure safe travel and the timely transportation of goods and services to keep Maryland’s economy moving. Sodium chloride – or salt – is effective, relatively inexpensive, readily available, and easily stored. But salt can destroy a soil’s structure and cause erosion, can damage and kill vegetation, and can contribute to the corrosion of metal bridges and motor vehicles. It can also seep into groundwater and runoff into surface waters, contaminating wildlife habitats and potentially affecting drinking water.
Some Maryland streams are identified as being polluted by chlorides, which affects freshwater aquatic life. MDE has increased monitoring for chlorides to gain information that can be used in developing restoration plans.
Salt in drinking water can be a health threat to people on sodium-restricted diets due to concerns about high blood pressure. Chloride can add a salty taste to water and corrode pipes. Road de-icing can cause increases in sodium and chloride concentrations in drinking water reservoirs, rivers that are sources of drinking water, and private and public water system wells.
Once the salt has entered the environment, there is no effective way to remove it. The best solution is a widespread, decreased use of road salt.
MDOT SHA has moved to use proactive strategies to reduce road salt use. The agency uses salt brine – a liquid solution that is 22 percent salt and 78 percent water – before, during, and after winter weather events. Pre-treating roads with salt brine prevent the initial bonding of snow or ice, giving road crews time to mobilize. The agency now has two “tow plows” – separate plows towed behind a salt/plow truck to clear an additional travel lane – which enhances snow clearing operations. More plowing means less salting.
MDOT SHA has also designated routes where only salt brine is used as a direct liquid application for the duration of a storm, using less salt overall when compared to routes where rock salt only is used. The agency pre-wets rock salt with salt brine to reduce the “bounce and scatter” effect of salt solids ricocheting off the highway. MDOT SHA also works with weather forecasters to develop a treatment plan and employs more than 100 mobile infrared sensors at key locations, along with mobile sensors, to determine conditions and target its storm deployment – greatly contributing to salt reduction efforts.
MDE is monitoring streams and reservoirs and is working with jurisdictions to control salt use and improve water quality. This is being done through the agency’s Nonpoint Source Program and its statewide designation under the federal Clean Water Act that uses of waters are not being supported or are threatened by salt. This designation requires jurisdictions to implement practices to reduce salt use.
Also, MDE has issued municipal stormwater permits to large local jurisdictions that include requirements for programs to reduce winter de-icing materials used. Permits recently issued to Baltimore City and Baltimore, Anne Arundel, and Montgomery counties require the countries to follow the example and guidance set by MDOT SHA, take steps to use improved equipment and methods, and to track and report salt usage. Other municipal stormwater permits that are in the works will include similar requirements.
MDE also recognizes that salt use by private entities, such as facility managers maintaining parking lots and other surfaces or property managers hiring winter maintenance contractors, is an area where salt use should be reduced. The agency recently began to develop a curriculum for online and in-person training for these salt users. Also, MDE is engaging in partnerships, on the federal level through a program led by the State of Minnesota and the U.S. Environmental Protection Agency’s regional office for the upper midwest, and locally with the Metropolitan Council of Governments and WSSC Water.
Many Maryland residents use salt to reduce ice accumulation on steps, walkways and driveways. In addition to the effects on water quality and vegetation, de-icers can also be dangerous for children and pets. Tips for reducing or eliminating the use of excessive de-icers at home include
- Clear walkways and other areas before the snow turns to the ice to avoid the need for chemical deicers.
- Track the weather and only apply deicers when a storm is imminent. If a winter storm does not occur, sweep any unused material and store it for later use.
- Only use deicers in areas where they are critically needed and apply the least amount necessary to get the job done.
- Store de-icing materials in a dry, covered area to prevent runoff.
- Reduce salt use by adding sand for traction, but take care to avoid clogging storm drains. Natural clay cat litter also works well.
- If your source of drinking water is your own private well, avoid applying salt near the wellhead.
- MDE Winter Salts StoryMap
- MDE Nonpoint Source Program salt page
- MDOT SHA salt fact sheet
- MDOT SHA tow plow fact sheet