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Self-salting roads might one day make winter driving safer | CBC Radio

Canadians are all too familiar with icy roads and treacherous driving conditions, especially before the snow plows, gritters and salters arrive. But scientists in China have developed a novel additive for asphalt containing embedded salt that enables the road to melt ice on its own.

The most common material used to melt road ice is rock salt — plain old sodium chloride. In Canada, more than five million tons of salt are spread on roads every year.

While it is effective at clearing roads of snow and ice, salt has negative effects on roadside vegetation, soil, birds and freshwater ecosystems. Salt-laden runoff water is briny, making it difficult for aquatic life, and it can contaminate groundwater. 

On top of that, there is the corrosive effect of salt on vehicles and roadways themselves.

Alternatives to road salt, such as calcium chloride, magnesium chloride or other chemicals, have been used, but many still have environmental effects. And of course, there's a cost to all that salt and the machinery and labour to apply it. 

Another option, developed over decades and used in some areas, is to incorporate salt into the asphalt mix when the road is laid or resurfaced. This salt is then released when the road is icy – the road essentially salts itself as needed.

It's a clever idea that's much more complicated than it seems. The salt needs to be mixed with additives to make it release only at appropriate temperatures, at an appropriate rate, and not leave voids in the road-bed that would weaken it and cause the pavement to break down.

Researchers in China reporting in the American Chemical Society journal ACS Omega have released their study of the latest, improved iteration of this idea.

They started with a sodium acetate salt – rather than a traditional chloride salt – which is less corrosive, making it kinder to the vehicles and road infrastructure. They encapsulate it in small polymer spheres that are incorporated into asphalt while it is being made.

The researchers designed the polymer capsules with tiny channels that release salt at a very slow rate, so they estimate a roadway could remain ice resistant for at least eight years. 

The salt is slowly released onto the surface of the road over time to act as a melting agent that is present before the snow falls. In a real world test, a ramp on a Beijing expressway was covered with a five-centimetre deep layer of treated asphalt and did not accumulate snow as readily as untreated ramps. 

They also found that if snow and ice accumulate during a heavy storm, a water layer forms between the ice and the road surface that makes it easier to break the ice up, even by regular traffic. 

An ice-melting road would require less plowing, which translates into lower maintenance costs and less wear-and-tear on the pavement.

In an attempt to keep the cost of the new material down, the salt was made from industrial biomass by-products, and mixed with waste slag from steel manufacturing to provide a mechanical structure that can withstand the pounding of vehicles. 

According to the RCMP statistics from 2017, nearly one-third of all vehicle accidents in Canada involve wet, snowy or icy roads, while insurance companies report a nearly 50 per cent increase in claims during December and January. 

While this self-salting technology is still in the experimental stage, someday, ice-melting roads could contribute to enhancing road safety — especially in this country, where driving on ice is an annual necessity. 

Researchers Are Creating Road Salts That Aren't Terrible For the Planet (goodgoodgood.co)

Many people associate a fresh snowfall with pleasures like hot chocolate and winter sports. But for city dwellers, it can also mean caked-on salt that sticks to shoes, clothing hems, and cars.

That’s because as soon as the mercury dips below freezing and precipitation is in the forecast, local governments start spreading de-icing salts to keep roads from freezing over.

These salts are typically a less-refined form of table salt, or sodium chloride, but can also include other compounds, such as magnesium chloride and potassium chloride. They work by lowering the freezing point of water.

De-icing salts also do extensive damage to autos, infrastructure, and the environment. And cities use them in enormous quantities — nearly 20 million tons per year in the U.S. Snowbelt cities in Canada, Europe, and Japan also use de-icing salts heavily.

But new options are in the works. I am a materials scientist seeking solutions for our overly salted sidewalks by analyzing ways in which the natural world deals with ice.

Fish, insects, and even some plants have learned to adapt to cold climates over hundreds of thousands of years by making their own antifreeze agents to survive subfreezing temperatures.

By taking a page from nature, my colleagues and I hope to develop effective but more benign antifreeze compounds.

Harmful impacts of salt

As many drivers know too well, road salt reduces cars’ lives by speeding up the rusting process. A 2010 study estimated that the use of de-icing salts costs U.S. drivers US$23.4 billion dollars nationwide yearly in vehicle damage due to corrosion.

Road salts also damage the surfaces we drive on. They contain chlorine ions — atoms with a negative charge — that alter the chemistry of water and make it more corrosive when it comes in contact with materials like concrete and steel.

As a result, road salts increase existing strains on aging structures. De-icing salts have contributed to bridge failures and cause cracking and other forms of weathering in highway surfaces.

De-icing salts have widespread effects in nature too. If you drive along a forested road after a long snowy winter, you may notice that trees next to the road look a little more brown than the others.

That’s because road salts displace minerals in soil and groundwater, creating a condition known as physiological drought.

This means that trees cannot take up water through their roots even if it is freely available in the soil. When natural drought conditions already exist, in such places as Colorado, physiological drought can increase the risk of wildfires by making plants more prone to ignition.

Streams, rivers, and lakes are especially vulnerable to water runoff that contains de-icing salts. Chlorine from the salt can inhibit fish from spawning and reduce dissolved oxygen levels in the water, which harms fish and other aquatic life.

Salt-laden runoff can also promote the growth of dangerous cyanobacteria, also known as blue-green algae. Some forms of blue-green algae produce toxins that can sicken humans or animals that consume them in drinking water.

Natural antifreezes

An alternative de-icing option should be nontoxic and break down into benign components – but not too quickly, or its effects won’t last. To see why this is important, consider propylene glycol, which is used to de-ice aircraft.

Propylene glycol is preferred for this purpose because it is less toxic than the ethylene glycol that keeps your car radiator from freezing up.

But propylene glycol’s effects are short-lived, so aircraft typically can wait for only a limited period between de-icing and takeoff.

This is also why propylene glycol is rarely sprayed on roadways and surfaces. Furthermore, although it is generally classified as safe for humans, it can still be deadly for aquatic life.

What about natural alternatives? Scientists have found insects and spiders in Alaska that create antifreeze proteins in their bodies that lower the freezing point of water by a few degrees. And some fish, like the Antarctic toothfish (Dissostichus mawsoni), create antifreeze glycoproteins that prevent the blood in their veins from freezing in the coldest waters on Earth.

Most of these glycoproteins are delicate structures that break down quickly in the harsh outside world. But my colleagues and I are learning how to make our own antifreeze compounds through imitation. Our first challenge is to learn how the natural versions work so we can re-create them.

While there’s still much we don’t understand, we are using advanced computer modeling to see how antifreeze proteins interact with water molecules.

Other scientists have discovered that fish antifreeze glycoproteins contain two main segments, and that certain sections are more essential than others.

Specifically, small compounds called hydroxyl groups, which consist of hydrogen and oxygen atoms, do most of the work.

These small compounds lock into place with water molecules, like a key in a lock, to prevent ice from forming. They are also part of most critical sections of the proteins that bind to the surface of any developing ice crystals and prevent them from getting bigger.

Antifreeze proteins are natural polymers – enormous long molecules consisting of smaller repeating molecules, like links in a chain.

Re-creating these compounds is no easy task, but we can create our own synthetic versions in a lab, starting with polyvinyl alcohol, or PVA.

This is a simple, inexpensive compound that is nontoxic to humans and aquatic

life and is a common ingredient in many everyday personal care products.

PVA contains the same hydroxyl groups as those found in fish antifreeze proteins. Using a bit of chemical engineering, we can change where those hydroxyls are located in the polymer structure, making it more like the compounds that fish produce.

In the future, we may be able to change PVA from an everyday compound into an ice-fighting substance that can be used just about anywhere.

Because PVA doesn’t degrade too quickly, it has the potential to work on surfaces that need to stay ice-free, such as roads, sidewalks and handrails. Its long chemical structure makes it suitable for shaping and adapting into sprays or coatings.

Someday cities may rely in winter on nontoxic spray-on antifreezes that won’t stain your clothes or corrode your car.

Salt, sand, and beets: What's the best de-icing method? - The Weather Network

Conventional solutions like salt and sand are used to pre-treat roads before they become dangerously slippery. But, the high use of road salts has been linked to environmental problems because salt contains high levels of chloride. About five million tonnes of road salts are used in Canada each year to mitigate ice and snow conditions on roads. However, almost all chloride ions from road salts eventually find their way into waterways, according to the Government of Canada.

Sand is another popular de-icing method used by many municipalities, used to increase friction between icy pavement and vehicles passing over. But, several studies and municipal evaluations have found sand to be relatively ineffective, according to Lake Simcoe Region, Conversation Authority. One of the main issues is that sand blows off the road with just a few vehicle passes at speeds over 40 km/hr. The biggest drawback is that many municipalities still mix sand with salt.

So, what about beet juice?

The beet juice blend works by lowering the freezing temperature of the brine solution which still contains salt, but not as much. While sodium chloride can help pretreat roads at around -7°C, when mixed with beet juice, the sugars help to drop the freezing point even more. As a result, ice shouldn't form unless it’s extremely cold.

Due to the sticky nature of beet juice, this type of ice melt minimizes the amount of salt that runs off into waterways. It is less corrosive, reuses a byproduct, and is easier on our vehicles, pavement, and plants. The only drawback is that it can leave behind a red mark, but it's not permanent and will not cause property damage.

Why desalination won't save states dependent on Colorado River water (cnbc.com)

KEY POINTS

• States dependent on the drought-stricken Colorado River are increasingly looking toward desalination as a way to fix the river’s deficit and boost water supplies across the western U.S.
• The search for alternative ways to source water comes as federal officials continue to impose mandatory water cuts for states that draw from the Colorado River.
• Desalination plants are costly to operate, require enormous amounts of energy and are difficult to manage in an environmentally-friendly way, according to water policy experts.

States dependent on the drought-stricken Colorado River are increasingly looking toward desalination as a way to fix the river’s deficit and boost water supplies across the western U.S.

The search for alternative ways to source water comes as federal officials continue to impose mandatory water cuts for states that draw from the Colorado River, which supplies water and power for more than 40 million people.

Desalination (or desalinization) is a complicated process that involves filtering out salt and bacteria content from ocean water to produce safe drinking water to the tap. While there are more than a dozen desalination plants in the U.S., mostly in California, existing plants don’t have the capacity to replace the amount of water the Colorado River is losing.

“Ocean water desalination has tremendous allure,” said Robert Glennon, a professor emeritus of law and water policy scholar at the University of Arizona. “The thought is that if we can just get the salt out of the water, everything can be fixed. But it’s a kind of siren song that will turn bad.”

Desalination plants are costly to operate, require enormous amounts of energy and are difficult to manage in an environmentally friendly way, according to water policy experts.

The debate over whether desalination could be a solution for the drying Colorado River comes as a historic megadrought grips the western U.S., generating the driest two decades in the region in at least 1,200 years. Water levels in the country’s two largest reservoirs, Lake Mead and Lake Powell, have hit their lowest levels on record.

The Biden administration has urged seven states in the Colorado River Basin to save between 2 million and 4 million acre feet of water, or up to a third of the river’s average flow. But water managers say that savings will need to be much more drastic as drought conditions worsen in the basin.

Kathryn Sorensen, who directs research at the Kyl Center for Water Policy at Arizona State University, said that while there’s been some major progress on water conservation across the West, the Colorado River is severely overallocated and the low reservoir levels are “extremely problematic.”

“We have been taking more water from the river than Mother Nature can really provide,” Sorensen said. “The river is a super important resource for all of us.”

The cost of water is high

Since desalination is a drought-resistant process, some have argued that states with such facilities could make themselves less dependent on water from the Colorado River. But the cost of desalination is high compared to the cost of imported river water and the process requires a great deal of energy to separate salts and other dissolved solids from water.

Large-scale plants require “tens of megawatts” to operate, according to the Energy Department, and energy consumption is the largest component of the operational expenditures of desalination, comprising about 36% of the total operational expenditures.

For example, the Carlsbad desalination plant in San Diego, California requires about 35 megawatts of electricity to operate. (By comparison, 1 megawatt is enough energy to operate a small town and 1,000 megawatts is enough to power a midsize city). The plant produces an average daily flow of 50 million gallons, only about 10% of the total drinking water needed by San Diego.

The cost of desalinated water at Carlsbad is estimated at $2,725 an acre-foot, according to a recent analysis by environmental economist Michael Hanemann of Arizona State University. That’s significantly more than the amount the San Diego County Water Authority pays for water sourced from the Colorado River and the Sacramento San Joaquin River Delta. Last year, the Water Authority proposed increasing its rate to $1,579 per acre-foot for untreated water in 2023.

“Desalination technology has improved greatly and it’s now remotely plausible to do,” said Jay Lund, co-director of the Watershed Sciences Center at the University of California, Davis. “But it’s only plausible if you’re willing to pay a lot of money.”

Water policy experts have also long debated the possibility of taking water from the Sea of Cortez in Mexico, the nearest sea to Arizona. In fact, Arizona officials in December voted to advance the study of a $5 billion project led by an Israeli company to build a plant to desalinate seawater in Mexico and transport it in a pipeline that would cross through the Organ Pipe Cactus National Monument.

The company leading that project said it would deliver up to 1 million acre-feet of water to Arizona, roughly the amount that the central and southern part of the state used from the Colorado River in 2022. The first phase of the plan would be a single pipeline that would transport roughly 300,000 acre-feet of water to Arizona, with future pipes supplying up to 1 million acre-feet.

If the desalinated water were to cost between $2,000 and $3,000 an acre foot for the Mexico plant, then the cost could potentially total up to nearly $1 billion each year for 300,000 acre-feet of water. And the cost could reach nearly $3 billion per year for 1 million acre-feet of water.

The environmental costs to desalination

There are also environmental costs to desalination. In addition to the greenhouse gases emissions produced from the large amount of energy needed to operate, the process leaves behind leftover brine, or concentrated salt water, which can raise the salinity of seawater and damage local marine systems and water quality as a result.

Brine can contain toxic metals such as mercury, cobalt, copper, iron, zinc and and nickel, as well as pesticides and acids that cause irrevocable changes to the environment.

“It’s difficult to bring desalination projects to scale because desalination is extremely expensive and there are real problems disposing with the brine that’s leftover,” Sorensen said.

One study published in the journal ScienceDirect found that brine volumes are greater than most industry estimates, comprising on average a gallon and a half for each gallon of fresh water produced. The authors urged brine management strategies that limit the negative environmental impacts and reduce the economic cost of disposal.

However, the most widespread current practice is to dump the leftover brine back into the ocean, which has led to the death of fish populations and corals as well as damage to seagrasses and fish larvae.

California regulators last year rejected a $1.4 billion desalination plant in Huntington Beach, citing not only the costs of the water but the hazards to marine life and risks associated with sea level rise and flooding.

Desalination will be useful in some areas of the country, especially as operating costs come down and more research is done on brine disposal. But water policy experts have suggested alternatives that are currently less expensive and energy-intensive and don’t pose environmental hazards.

Lund said that fallowing lower value agriculture is a cheaper and better alternative from a national and state perspective, since agriculture uses approximately 80% of the Colorado River’s water. “It’s the cheapest and most sustainable way to bring the system back into balance,” Lund said.

Reusing wastewater, conserving water and encouraging the reallocation of water are other sustainable solutions to water shortages that should take priority over desalination, Glennon said.

“Desalination is not a silver bullet. There are immense challenges,” Glennon said. “We can do it, there’s no doubt about that — but it isn’t the only option.”

To salt or not to salt? | Living Green | willistonobserver.com

Ice-melting salt is useful in winter but can pollute soil and water

The United States uses an estimated 20 million metric tons of salt on roads every year.

In places like the Lake Champlain basin, the long, cold winters mean a lot of salt applied on our roads and sidewalks. But all of that salt can pollute our soils and waters and harm local ecosystems.

“Road salt can make its way via streams to local lakes and ponds,” said Kris Stepenuck, associate director of the Lake Champlain Sea Grant, a program of UVM that produces scientific work to benefit the Lake Champlain basin. “Once there, it will only accumulate and can cause unsafe — or even toxic — conditions for fish and other aquatic life.”

What can you do to protect local forests and waterways when using ice-melting salt? Follow these guidelines.

Check to see if the conditions are right

Salt depresses the freezing point of water, which makes it effective at reducing ice formation and accumulation on streets and sidewalks in the winter—down to a certain temperature. Sodium chloride, the most common type of road salt, is not effective when the pavement temperature is colder than around 16 degrees.

So, be sure to check the temperature of the pavement with an infrared thermometer before you salt. If it’s too cold, opt for an alternative such as gravel, sand or even cat litter. These materials will provide extra traction to help prevent slipping while also absorbing more heat from sunlight, which helps melt the snow.

If your driveway is gravel or dirt, applying salt is even more harmful for the environment and can cause dangerous conditions for driving. Instead, try salt alternatives like gravel, sand or cat litter to increase traction.

Salt before the snow

So, you’ve just checked the forecast to see if it’s the right temperature to apply salt and saw a big storm rolling in. What can you do? If you salt before the storm, it provides a buffer between your driveway and the snow, which makes shoveling easier and driving safer.

Bonus points if you dissolve the salt in water first and spray the mixture on your driveway.

“Using a 23 percent salt-water solution acts like butter in a frying pan,” Stepenuck said. “This reduces the ability of snow and ice to bond with the surface. Using a salt-water mixture can reduce total salt use and make it easier to plow or shovel after the storm. Plus, since any dry salt you spread must combine with water to minimize ice formation, the mixture can work its magic more quickly than if you spread dry salt.”

Shovel, then salt

If you apply salt to your driveway when it already has a layer of snow on it, the salt will need to seep through the layer of snow before it can start working, meaning you would need more salt to keep the driveway free from snow and ice. Instead, shovel first and apply the salt as close to the pavement as you can.

Use the right amount

Salt is often spread on driveways and sidewalks without much rhyme or reason, but the amount of salt you use matters. A good rule of thumb is to spread no more than a cup or a cup and a half of rock salt for every 10 sidewalk squares or every two parking spaces. There should be about 3 inches between each of the salt grains.

Using more than that doesn’t make it more effective, it just allows more salt to runoff into the environment, to be tracked into the house or to damage doors, steps or other structures. And it wastes money.

If you used too much salt and see it on your driveway or walkways after the snow is gone, sweep it up. You can save it and use it for the next storm. Otherwise, this excess salt will slowly infiltrate into the soil around it or run off your driveway, ultimately polluting a nearby waterway.

Tell your neighbors

The best way to increase your impact is to get other people on board. Share these tips with your friends and neighbors so that we can all have a safe and sustainable winter. Happy shoveling!

 For more information, email seagrant@uvm.edu.

Settling in for winter: Road salt impacts groundwater year-round | Mirage News

Research explains the impacts deicers have on groundwater resources

January 25, 2023 – For many parts of the United States, winter weather can impact road conditions. To reduce hazardous conditions caused by snow and ice, many counties, municipalities, homeowners, and others use deicers. Salt is the most common option to treat roads.

But how might road salt impact groundwater? Does it have impacts only in winter, or does it have lasting impacts year-round?

These are key questions that Rachel McQuiggan, a researcher at the Delaware Geological Survey, and colleagues wanted to answer. In their research, they monitored stormwater and groundwater at an infiltration basin. An infiltration basin is a large, shallow roadside pool that allows stormwater to infiltrate into the groundwater.

The research was published in the Journal of Environmental Quality, a publication of the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

“Most stormwater management practices are designed to protect surface waters,” says McQuiggan. “Infiltration basins, and even some types of green infrastructure, are designed with the idea that stormwater benefits from a natural ‘filtering’ of contaminants as it infiltrates through soil, and contaminants dilute as that recharge mixes with existing groundwater.”

She adds that these are used to prevent contaminants like salt from being discharged straight into surface water. But in states like Delaware, groundwater contributes up to 80 percent of the water in rivers and streams. This means that salt will eventually reach rivers and streams, just on a longer timescale.

The researchers monitored the infiltration basin from mid-May 2019 to mid-February 2022 to evaluate the impact road salt had on groundwater quality. One aspect of their findings showed that geological complexity, such as differences in subsurface soil properties, influenced how salty stormwater moved through groundwater.

The researchers explained it is important to consider things like placement, depth, and frequency of monitoring groundwater to get the full picture.

The team found that groundwater is impacted by road salt throughout the year, not just during winter. This is because the salt is retained in the soil in the infiltration basin. Salt is made of sodium and chlorine atoms, and chloride more easily moves in water. However, sodium more easily latches onto soil particles.

During other parts of the year, stormwater that does not contain much salt enters the basin and flushes sodium from the soil into the water. The results of the study also suggest that a higher salt content can cause radium to enter the groundwater.

“Climate can really impact the timing of how this all plays out,” McQuiggan explains. “For example, if it’s a particularly dry spring and summer, then the sodium can take longer to reach groundwater. And in Delaware, snowfall typically melts and runs off the roads within a few days of falling. In colder climates it can stay frozen for months.”

While there are other deicers available, they are not all as effective as road salt and each has its own pros and cons. Sand is a popular option to increase traction and minimally affect groundwater but could require extra maintenance like street sweeping, says McQuiggan.

“There are even carbohydrate deicers, like beet juice,” she says. “However, most alternatives are used in conjunction with salt or acetate because those are so effective and road safety is incredibly important. Each option has its pros and cons in terms of impact to the environment and cost.”

Many cold areas depend on deicer to ensure the safety of drivers, bikers, and pedestrians. The researchers say their work provides direction on how to best monitor the impacts of deicer on groundwater so adjustments can be made if needed.

“Groundwater supplies almost half of all drinking water worldwide,” says McQuiggan. “In central and southern Delaware, groundwater is the only source of potable drinking water. Hopefully the results of this project will encourage best management practices for deicer use to protect groundwater resources.”

Funding for this research was provided by the Delaware Department of Transportation. The research team is affiliated with the Delaware Geological Survey and the University of Delaware’s Department of Earth Sciences.

Journal of Environmental Quality publishes original research, reviews and analyses, and environmental issue articles that address anthropogenic impacts on water, soil, and the atmosphere and pertain to some aspect of environmental quality in natural and agricultural ecosystems.

The American Society of Agronomy is an international scientific and professional society with its headquarters in Madison, WI. Our members are researchers and trained, certified professionals in the areas of growing our world’s food supply, while protecting our environment. We work at universities, government research facilities and private businesses across the United States and the world.

/Public Release. This material from the originating organization/author(s) may be of a point-in-time nature, edited for clarity, style and length. The views and opinions expressed are those of the author(s).View in full here.

Road salts wash into Mississippi River, damaging ecosystems and pipes (qctimes.com)

This winter has already brought significant snowfall to much of the U.S. Historically, more snow has meant more road salt. It’s an effective way to clear roads — but also brings cascading environmental impacts as it washes into rivers and streams. 

But amid one powerful winter storm that walloped the Midwest in December, employees from the La Crosse County Facilities Department in Wisconsin did something a little different. 

As usual, they clocked into work well before dawn to plow the county’s downtown parking lots. They were followed by facilities director Ryan Westphal, who walked each of the lots, checking for slick spots. Finding none, he didn’t lay any salt down on top. 

That’s a major departure from how he would have handled the situation a few years ago – before their department made the decision to dramatically cut back on salt use to prevent it from flowing into waters like the nearby Mississippi River, which new data show has been growing saltier for decades.

Under the previous protocol, in Westphal’s words, his crew would have “salted the crap” out of the lots after a snowfall like this, without giving deference to whether they actually needed it. Today, there’s a careful calculation after each time it snows to ensure they’re using just the right amount of salt. 

Westphal acknowledged that the new way isn’t faster, nor is it easier. If a half-inch of snow falls today, for example, a handful of employees will take a few hours to plow the lots, versus the one employee who could have thrown salt down in an hour. 

But he said the extra time is worth it. 

“There’s pretty good evidence that if we continue to use salt at the rate we do now, it’s going to be detrimental to the rivers and lakes eventually,” Westphal said. “We need to do something about it now.” 

The use of road salt during winter is nothing new for people across the Midwest, particularly in its upper stretches where the presence of snow and ice can linger from December into April. But there’s growing awareness of the harm it can cause to freshwater resources – wreaking havoc on aquatic life, disrupting ecosystems, making its way into groundwater and corroding pipes. 

New data reveal that levels of chloride – one of the elements that make up salt – have increased by more than a third since the late 1980s across the entire Upper Mississippi River basin, which extends from the river’s headwaters in Minnesota to southern Illinois. Reported increases are even higher at monitoring sites in Wisconsin and Minnesota. And the problem is magnified in smaller rivers and streams that can’t flush the same volume as the Mississippi. 

There are other reasons for increased chloride in water, like salt from water softeners and the use of potassium chloride fertilizer, but road salt is typically a dominant source in colder states. 

It’s leading people like Westphal – as well as those in state and federal environmental agencies – to realize a change is needed. 

The river is getting saltier 

Unlike other pollutants, chloride doesn’t break down in water over time. In other words, once it’s in, there’s no getting it out. Just a teaspoon of salt can pollute five gallons of water forever. 

So the increase in chloride in the river isn’t from a recent overabundance of road salt being laid down in the winter months. It has built up over decades. And because it doesn’t break down, it’s all headed down into the Gulf of Mexico. 

In a forthcoming report on water quality in the upper river, the Upper Mississippi River Basin Association (UMRBA) found that chloride had increased at least 35% across the basin between 1989 and 2018. All 14 sites on the river where chloride was measured, plus one on the Illinois River, which feeds to the Mississippi, showed increases in the pollutant during that time period, according to UMRBA data. 

At a Wisconsin Department of Natural Resources monitoring site in Lynxville, about an hour south of La Crosse, chloride levels in the river had increased by more than 60% since the 1980s, according to a 2021 study from two Mississippi River water quality specialists with the DNR. 

And chloride levels in the portion of the river that runs through the Twin Cities metro area increased 81% between 1985 and 2014, according to a 2016 report from the nonprofit group Friends of the Mississippi River. 

Chloride levels are rising at all 43 DNR river monitoring sites across Wisconsin.

“It really shows that we’re not on a sustainable path,” said Shawn Giblin, who coauthored the 2021 DNR study. “You can’t keep having 1 to 4% annual increases. You’re eventually going to get to chronic toxicity levels.” 

The concept of freshwater becoming saltier, known as freshwater salinization syndrome, isn’t unique to the upper Midwest. In November, the U.S. Environmental Protection Agency said its scientists have been studying the issue because of “dramatic” salt concentration increases in freshwater around the country and globally. 

Both the EPA and state environmental agencies set limits for when chloride becomes toxic to aquatic life. In Wisconsin, for example, 395 milligrams per liter of chloride in a water body for days at a time is considered chronically impaired, while 757 milligrams per liter, which is instantly toxic to fish, is considered acutely impaired. 

Though the Mississippi River is under the limit, many smaller tributaries are not. In Minnesota, 50 lakes and streams are considered impaired by chloride, and another 75 have chloride levels near the standard, according to the state’s pollution control agency. In Wisconsin, 51 rivers and one lake are chronically impaired by chloride, DNR data show – most in the southeast part of the state. 

Ecosystems hurt by high chloride

High chloride levels can have far-reaching destructive impacts on ecosystems. 

Salt increases the electric current in a body of water and makes the overall environment less habitable, said Lauren Salvato, who coordinates the water quality program for the Upper Mississippi River Basin Association. By adding more and more to the water, the ecosystem starts acting more like an estuary, an area where a freshwater river or stream meets the ocean.

Toxic amounts of chloride can kill freshwater aquatic plants and animals. That includes zooplankton, microscopic animals that feed on algae. Die-offs can then lead to harmful algal blooms, which have their own adverse effects. 

Chloride can also make its way into groundwater, the source of  drinking water for about two-thirds of Wisconsinites and about three-fourths of Minnesotans. Salt’s other component – sodium – can alter the taste of water and could pose health risks for people who are on low-salt diets. 

Finally, elevated chloride levels can also pose an infrastructure problem, corroding lead and copper drinking water lines and leading to contamination.

Searching for solutions

Many municipalities are already experimenting with ways to fix the problem. Brining, where salt is mixed with water before being applied to roads, resulted in a 23% reduction in salt use on average on Wisconsin highways, a 2022 study from the University of Wisconsin-Madison found. Some places even use beet juice to help the solution work at a lower temperature, since standard road salt is much less effective at temperatures lower than 15 degrees. 

That can be combined with other techniques, like pre-wetting salt so it doesn’t bounce off roads and using underbody plows, which can remove hard-packed snow better than plows with a front blade. 

In Minnesota, the state pollution control agency leads a Smart Salting training program to help road salt applicators better understand how too much salt can affect the environment. The training aims to help applicators identify the best balance between ensuring safe traveling conditions and protecting the environment. 

To date, about 5,300 people are currently certified under the program, said Brooke Asleson, the state’s chloride reduction program coordinator. 

The idea emerged in 2005, sparked by concern about Shingle Creek, which joins the Mississippi River in Minneapolis and was the first water body in the state to be designated as chloride-impaired about a decade prior. 

Two years ago, the state made it a requirement for any entity that receives a municipal stormwater permit to get trained on proper salt use and the importance of protecting water quality. Enrollment in the Smart Salting training has significantly increased since then, Asleson said. 

Some participants simply weren’t aware that they could be using less salt, she said. After implementing techniques from the training, many are able to cut their salt use in half. 

One other change that could make a difference: protecting people from slip-and-fall lawsuits as long as they follow proper salting guidelines. 

“Ultimately, the fear (from applicators) is if they don’t put enough road salt down, someone’s going to slip and sue them,” said UMRBA’s Salvato. 

New Hampshire legislators passed a law in 2013 that gave partial immunity from lawsuits to snow-removal companies that participated in a voluntary training program for applying road salt. Similar bills have been floated in Minnesota – where it’s been proposed but not yet passed – and Wisconsin, where one is currently being drafted.  

Communicating why it matters

Advocates for reducing road salt say public awareness is critical. 

The general public is “mostly unaware” of trends in chloride contamination and the harmful effect it can have on the environment, according to a chloride resolution UMRBA adopted in February 2022. The resolution aims to facilitate upper basin states working together to reduce chloride in the river. 

The EPA has also convened a group of cold-weather states to help them share information about easing the impacts of winter road maintenance on the environment. 

“It is a big lift to tackle this chloride issue,” Asleson said. “The more collaboration we can do as states to share information and knowledge with each other, the better off all of us will be at protecting our environment.” 

For Westphal, in La Crosse County, it wasn’t hard to convince his staff to get on board with being more mindful of their salt use because many of them share his appreciation for the Mississippi River and nearby lakes. His passion for the issue comes from a longtime friendship with Giblin, the Wisconsin DNR water quality specialist. 

But this winter, which has already been a snowy one, could be a big test. 

To get more salt applicators on board, Westphal sees three things that need to happen: Grant money for brining equipment and other materials, protection from lawsuits, and finally, some pressure from the state to heavily encourage people to make the switch. 

Westphal said it comes down to “selling people on the right thing versus the easy thing.” 

The Mississippi River, running just blocks away from their downtown campus, serves as a powerful reminder of why he thinks it’s right. 

Road salts wash into Mississippi River, damaging ecosystems and pipes is a post from Wisconsin Watch, a nonprofit investigative news site covering Wisconsin since 2009. 

Reduce salt use this winter | Outdoors | apg-wi.com

MADISON – The Wisconsin Department of Natural Resources (DNR) and Wisconsin Salt Wise invite the public to learn more about the impacts of road salt on drinking water and freshwater ecosystems during Wisconsin Salt Awareness Week Jan. 23-27.

Wisconsin Salt Awareness Week will include a series of YouTube livestreamsfeaturing speakers and topics focused on the true cost of salt and how to be a freshwater advocate. Speakers include Sujay Kaushal (University of Maryland), Charlie Paradis (University of Wisconsin–Milwaukee), Allison Couture (University of Wisconsin–Madison), Shannon Haydin (Wisconsin DNR) and Allison Madison (Wisconsin Salt Wise). Register in advance or watch afterward on the Wisconsin Salt Wise YouTube Channel.

While salt keeps Wisconsin roads safe during winter, using more salt than needed comes at a price. In Wisconsin and much of the United States, chlorides from salt are infiltrating lakes, streams and groundwater. According to Wisconsin Salt Wise, 1 teaspoon of salt is all it takes to make 5 gallons of water toxic for freshwater organisms.

The DNR measures chloride levels in Wisconsin rivers over time, monitoring cumulative chloride loading results at 26 of the state’s largest river systems. Recent studies have shown a steep increase in chloride loads. In the early 2000s, the DNR measured about 600,000 tons of chlorides annually. By 2018, that number increased to nearly 800,000 tons per year. Fifty lakes and one stream in Wisconsin have been designated as impaired by high salt concentrations.

These increased chloride loads are partly due to road salting, but chlorides also enter Wisconsin waters because of water softeners and fertilizers. Find out if your softener is salt-wise with this diagnostic tool.

Increased chloride levels have significant impacts on our daily lives, including environmental and economic effects. Nationwide, winter salt causes $5 billion in damage to infrastructure each year, causing corrosion of bridges, roads and other infrastructure. Road salt can also impact pets by causing irritated paws or other health concerns if ingested.

Salt tips for Wisconsin residents

Reducing salt use is key to decreasing chloride loads. Follow these steps to right-size your salt use:

Shovel. Clear walkways and other areas before the snow turns to ice. The more snow removed manually, the less salt you will need and the more effective it will be.

Scatter. When using salt, scatter it so that there is space between the grains. A 12-ounce coffee mug of salt is enough to treat an entire 20-foot driveway or 10 sidewalk squares. If you see over-salting, follow these simple steps to help educate others about salt.

Switch. Salt won’t work when pavement temperatures drop below 15 degrees. Switch to sand for traction or a different ice melter that works at lower temperatures.

Statewide reduction efforts

The DNR works to reduce chlorides at the source through permitting programs for municipalities and industries. These measures include tuning up or replacing water softeners, identifying significant chloride contributors and finding reductions, process efficiencies or improvements and instituting sewer use ordinances.

Additionally, the Wisconsin Department of Transportation works with Wisconsin counties to reduce road salt application using brine and pre-wetting road surfaces, both of which significantly reduce salt use.

Reduce salt use this winter | News | baldwin-bulletin.com

The Wisconsin Department of Natural Resources (DNR) and Wisconsin Salt Wise invite the public to learn more about the impacts of road salt on our drinking water and freshwater ecosystems during Wisconsin Salt Awareness Week, Jan. 23-27, 2023.

Wisconsin Salt Awareness Week will include livestreams featuring speakers and topics focused on the true cost of salt and how to be a freshwater advocate. Speakers include Sujay Kaushal (University of Maryland), Charlie Paradis (University of Wisconsin – Milwaukee), Allison Couture (University of Wisconsin – Madison), Shannon Haydin (Wisconsin DNR) and Allison Madison (Wisconsin Salt Wise). Register in advance or watch afterward on the WI Salt Wise YouTube Channel.

While salt keeps Wisconsin roads safe during winter, using more salt than needed comes at a price. In Wisconsin and much of the U.S., chlorides from salt are infiltrating lakes, streams, and groundwater. According to Wisconsin Salt Wise, one teaspoon of salt is all it takes to make five gallons of water toxic for freshwater organisms.

The DNR measures chloride levels in Wisconsin rivers over time, monitoring cumulative chloride loading results at 26 of the state’s largest river systems. Recent studies have shown a steep increase in chloride loads. In the early 2000s, the DNR measured about 600,000 tons of chlorides annually. By 2018, that number increased to nearly 800,000 tons per year. Fifty lakes and one stream in Wisconsin have been designated as impaired by high salt concentrations.

These increased chloride loads are partly due to road salting, but chlorides also enter Wisconsin waters because of water softeners and fertilizers. Find out if your softener is salt-wise with this diagnostic tool.

Increased chloride levels have significant impacts on our daily lives, including environmental and economic effects. Nationwide, winter salt causes $5 billion in damage to infrastructure each year, causing corrosion of bridges, roads, and other infrastructure. Road salt can also impact pets by causing irritated paws or other health concerns if ingested.

Salt Tips for Wisconsin Residents

Reducing salt use is key to decreasing chloride loads. Follow these steps to right-size your salt use:

• Shovel: Clear walkways and other areas before the snow turns to ice. The more snow removed manually, the less salt you will need and the more effective it will be.
• Scatter: When using salt, scatter it so that there is space between the grains. A 12-ounce coffee mug of salt is enough to treat an entire 20-foot driveway or 10 sidewalk squares. If you see oversalting, follow these simple steps to help educate others about salt.
• Switch: Salt won’t work when pavement temperatures drop below 15 degrees. Switch to sand for traction or a different ice melter that works at lower temperatures.

Statewide Reduction Efforts

The DNR works to reduce chlorides at the source through permitting programs for municipalities and industries. These measures include tuning up or replacing water softeners, identifying significant chloride contributors, and finding reductions, process efficiencies or improvements and instituting sewer use ordinances.

Additionally, the Wisconsin Department of Transportation works with Wisconsin counties to reduce road salt application using brine and pre-wetting road surfaces, both of which significantly reduce salt use.

For more information on the DNR’s efforts to monitor chlorides and reduce their effects, visit the DNR’s Salt and Storm Water website here.

Salty decision: Why the City of Barrie will be sprinkling more salt than normal on roads this winter (simcoe.com)

You may find the decision a bit abrasive, but the City of Barrie was left with few options.

The deteriorating condition of the Ferndale Drive North operations centre sand dome has forced the municipality to rethink its winter maintenance plans for road infrastructure.

Operations director Dave Friary says a structural inspection of the dome, carried out in the fall, revealed the building could not be used to store sand this season.

Instead, sand will be swapped for salt during more moderate temperatures at the beginning and end of winter. Salt will be used at low application only when required, to minimize environmental implications, he said.

“The trucks are all computerized now; they have spin rates and it cuts down on the amount we put down,” Friary said. “The last thing we want to do is contaminate (Kempenfelt) Bay.”

As salt supply depletes this winter, room will open for sand in an operations centre storage building, he said.

Typically, residential roads are maintained to snow-packed condition by plowing, then applying sand for traction.

But sand has limited effectiveness because it often blows off roads quickly. And high levels of chloride, one of the main components in winter salt, has become an issue in watersheds across northeastern North America, Lake Simcoe Region Conservation Authority environmental science and monitoring manager David Lembcke said.

“Barrie is very savvy with their winter maintenance,” he said. “They recognize anything you put down has an impact. There’s a bit of a ‘damned if you do, damned if you don’t.’  It’s juggling human safety versus environmental impact.”

Lembcke said chloride concentration in the lake has increased by .7 mg/L annually since 1971. And 81 per cent of all salt entering Simcoe comes off roads.

Salt concentration above the 120 mg/L threshold can affect the health of some sensitive freshwater species; 640 mg/L will kill many of those off altogether. Many urban creeks already exceed the first number throughout most of the winter and can surpass the second after melting events. 

Municipalities are more frequently applying less-salty anti-icing and brining techniques in advance of storms.

But climate change, and expanding road infrastructure from population growth, often offset those efforts.

“If we expect I can go out on bare roads an hour after snowfall, that puts unbelievable strain on winter maintenance,” Lembcke said.

The city’s plan also means a street-sweeping recycling program, where sand is reclaimed and reused at a roughly $200,000 annual cost savings to the municipality, has been suspended indefinitely. It also didn’t run last year.

Dieter Mueller, who ran unsuccessfully for a councillor seat in the recent municipal election, has long advocated for the recycling program to be kiboshed. He alleges it risks exposing residents to heavy metal, asbestos from some stretches of pavement, microplastics and vehicle liquids.

“I guess my message got through to them,” he said. “The amount of contaminants in the sand, once it is swept off the street, is quite high. It becomes dangerous. If it goes back on the street the following winter, it increases. It’s like compound interest.”

Friary disagrees with Mueller’s claim.

“It’s an accepted practice,” Friary said. “We (had) it tested annually and everything works out. It’s environmentally friendly. We take out all the large pieces — the coffee cups, cans (and) sticks. We’re reusing a product, rather than buying clean, virgin sand. We use 75 per cent virgin sand and mix in the street sweepings; it’s not all recycled.”

The city’s new salt plan meets Ontario’s maintenance standards for municipal highways. It is expected to remain in place until the operations yard is redeveloped, likely within two years. An update on the project is expected to be presented to council this spring, he said.