Study shows critical need to reduce use of road salt in winter, suggests best practices — ScienceDaily

Across the United States, road crews dump about 25 million metric tons of sodium chloride — as table salt — to unfreeze roads each year and make them safe to travel.

Use varies by state, but the amount of salt applied to icy roads annually in some areas can be anywhere from 3 to 18 pounds of salt per square meter, which is the size of just a small kitchen table.

As the use of dissolving salts has tripled over the past 45 years, salt concentrations are increasing dramatically in streams, rivers, lakes, and other fresh water sources.

Excessive use of road salts to melt snow and ice threatens human health and the environment as it leaches into drinking water sources, and new research from the University of Toledo has highlighted the urgent need for policy makers and environmental managers to adopt a variety of solutions.

The study, titled “Road salts, human safety, and the rising salinity of our fresh water” is published in the journal. Frontiers in ecology and the environment It presents how road salts harm the environment, pollute drinking water supplies and mobilize harmful chemicals, such as radon, mercury and lead, and then outlines proposed best management practices.

“The scale of the road salt pollution problem is significant and requires immediate attention,” said Dr. Bill Hintz, assistant professor of ecology at UToledo and lead author of the research that was established from the UToledo Lake Erie Center. “Given that road demining machines reduce car accidents by more than 78%, we have worked to strike a delicate balance between human safety and mitigating the negative environmental and health impacts of dumping salt on our streets and highways to keep people and traffic safe.”

In one prime example, researchers say the overuse of road salt likely contributed to high levels of corrosive chloride in the water supply in Flint, Michigan in 2014, which led to lead being released from water distribution pipes.

Another example shows that high concentrations of dissolving salt typically occur in private wells located near roads at lower elevations or slopes from highways.

The most common dehydrators are the inorganic salts of sodium chloride, calcium chloride, and magnesium chloride, all of which are used in solid, liquid, or brine form.

The study looks at how to exceed current federal safety limits for salt concentrations set by the U.S. Environmental Protection Agency in 1988 to protect fish, plants, and other aquatic life in freshwater ecosystems.

Of particular concern is the number of salt streams. The research highlights recent studies showing urban streams at salt concentrations 20 to 30 times greater than the EPA’s chronic chloride threshold of 230 milligrams per liter.

“It is clear that the current EPA thresholds are not sufficient,” Hintz said. “The effects of dissolving salts can be fatal or fatal at current thresholds and recent research suggests that negative effects can occur at levels well below these thresholds.”

The research suggests several solutions, including:

  • suitable storage facilities – structures covered with a concrete base;
  • antifreeze, placing fluids such as brines on road surfaces prior to winter storm events, which prevents ice from sticking to surfaces and aids in removals;
  • Live-edge snow plows consist of multiple small spring-loaded plows, which conform better to road surfaces than conventional single-edge fixed plows, to increase snow and ice removal efficiency and reduce the need for salt removal; And
  • Post-storm performance evaluations to determine if the treatment used is appropriate for the weather system and if it should be modified in the future.

“Given the lack of environmentally friendly and cost-effective alternatives, large-scale adoption of best management practices is essential to reduce the increase in salinization of freshwater ecosystems caused by the use of dissolving salts,” Hintz said.

Hintz collaborated with scientists from Montana State University and Rensselaer Polytechnic Institute on the study.

Story source:

Material provided by University of Toledo. Original by Kristen Bellau. Note: Content can be modified according to style and length.


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