MDC urges careful salt use in winter to protect water quality

Missourians enjoy healthy waters, and there is a step they can take in winter to help water quality in streams, ponds, and lakes in their neighborhood. The Missouri Department of Conservation (MDC) urges careful use of salt to melt ice and snow on driveways, parking lots, and walkways. Applying salt sparingly, and only when needed, can prevent harm to aquatic life from high chloride levels.

Just one teaspoon of sodium chloride, commonly known as salt, can make five gallons of water uninhabitable for most freshwater species. Small streams and lakes, particularly those in urban neighborhoods, hold aquatic life such as small fish, insects, and amphibians that are part of a natural life web in the stream corridor. Sport fish are also found in some larger waters in developed subdivisions. Heightened chloride levels harm freshwater life.

“In Missouri, elevated chlorides are more of an issue in metropolitan areas,” said Rebecca O’Hearn, MDC scientist. “There are spikes in winter when salts are applied, but there are also pulses during other times of the year. The pulses might be after a rain event when residual salts on paved areas and in roadside vegetation and soil are flushed into waterways.”

Treating winter conditions is not the only source of chlorides in streams and ponds. But it is a factor, especially during peak winter snow and ice conditions. Ice melt treatments can also harm soils, plants, and trees on a homeowner’s property.

Currently, aquatic life is listed as impaired due to chlorides in 17 Missouri streams, according to the Missouri Department of Natural Resources. Most of those streams are in the St. Louis area. Indian Creek in Jackson County is also listed as impaired.

Clearing snow from walkways and driveways before packed snow or ice can form can eliminate the need for salt. Using ice melt treatments sparingly when needed can help preserve water quality in a community.

For more information about the harm from chlorides to plants, trees, and soil, visit MDC’s website at https://short.mdc.mo.gov/44P. The page also has information about treating chloride damage to reduce problems for plants.