Salt spread on roads and sidewalks to melt snow and ice wreaks havoc on local streams and groundwater, not to mention our furry friends’ paws.

Ice-melting chemicals can harm children and dogs if swallowed, according to the National Capital Poison Center website. It also dries and irritates pets’ paws and skin as they walk through ice-melt chemical slush.

The center recommends wiping salty snow off of fur and paws as soon as they come inside, then rinsing paws to remove all residue.

Most pet stores sell pet-friendly versions of ice melt for your own sidewalk or driveway.

Along the roadside, salt damages street trees, runs off into streams and soaks into the ground where it can stick around for a long time, experts say.

“The concern about road salt extends back to the 1940s,” said Andrew Heyes, research professor at the University of Maryland Center for Environmental Studies’ Chesapeake Biological Laboratory. “More recently, the focus has shifted to the long-term ion balance around streams, with soils retaining and slowly releasing chloride and sodium, displacing calcium and magnesium.”

That means the nearly 400 tons of salt spread on Maryland roads each winter continues to affect the environment through the year and beyond, he said in emails to The Baltimore Sun. If Maryland stopped salting roads this year, local streams would continue to grow saltier for several years before recovering.

Some freshwater creatures can actually get dehydrated swimming in saltier streams, added colleague Carys Mitchelmore, who studies the effects of pollutants on streams and the Chesapeake Bay. Osmosis from salty water causes their bodies to shed water.

The average saltiness of central Maryland streams increased more than eight times from the 1970s to today, according to a Maryland Geological Survey study. This filters into drinking water drawn from private wells, too, causing pipes and appliances to rust prematurely.

“This has led to various salt best-management practices to reduce the amount of salt needed to be effective,” Mitchelmore said in an email to The Sun. “For example, removing the snow/ice first, then salting, and sometimes using a liquid brine.”

The Maryland Department of Transportation started this winter season with a $65 million stockpile, including 386,000 tons of rock salt stored in 87 facilities around the state. Rock salt melts snow and ice most effectively at temperatures above 20 degrees Fahrenheit.

Another 1.6 million gallons of brine, or saltwater, and 100,000 gallons of magnesium chloride are sprayed on dry roads before a significant snowfall to prevent snow and ice from sticking to roads.

The department says using brine exclusively on certain roads proves more effective at keeping them clear while using less salt per mile.

Brining presents some drawbacks, however. It requires purified salt, without impurities, to keep brine production facilities running efficiently. Pre-treating is also less effective if rain is expected before the snow, as rain will wash away the treatment.

According to the national nonprofit advocacy group Clean Water Fund, Maryland reduced rock salt use by 50% between 2013 and 2020 as brine pre-treatment became more common.

Alternatives to rock salt include agricultural byproducts like beet juice, pickle juice, brine from cheese-making and fermentation byproducts from beer and wine making. However, the University of Maryland’s Cary Institute of Ecosystem Studies says these agricultural products have their own downsides, adding organic matter to streams and lakes. This depletes oxygen, leading to algae blooms and fish kills.

What can you do?

The Cary Institute suggests reducing ice-melt use by shoveling early and often to prevent snow and ice buildup as a storm progresses. De-icers work best on a thin layer of ice. Once the snow has stopped, sprinkle salt sparingly.

Have a news tip? Contact Karl Hille at 443-900-7891 or khille@baltsun.com.