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  • 26 Mar 2023 8:06 AM | Smart About Salt (Administrator)

    Freshwater ecosystems are becoming increasingly salty. Here's why this is a concern (

    Freshwater ecosystems around the world are becoming saltier and saltier. Many human-driven factors contribute to freshwater salinization, including: irrigation, oil extraction, potash mining, and road de-icing.

    As a result, salts enter waterways. But as bad news never comes alone, the salts are often accompanied by a toxic cocktail of other pollutants, whose combined toxicological effects are largely unknown.

    Although the problem of rising freshwater salinization went largely unaddressed for many decades, it has gained considerable attention during the last 20 years.

    Scientists around the world are working together to understand the ecological impacts of increasing salinization on aquatic biodiversity and food webs. Our ultimate goal? To examine the adequacy of water quality toxicity thresholds for the protection of aquatic life.

    Salinization, a major problem

    Canada is home to a majority of the world’s freshwater resources, mostly concentrated in the provinces of Ontario and Québec, where close to 5 million tons of road salt are applied annually to de-ice roads.

    Combined with climate change and increasing frequency and duration of drought in many regions of the world, the problem is getting worse. This is a major concern. Why? Because the availability of freshwater resources will become a critical factor for humanity over the next 50 years.

    Researchers from around the world mobilized

    We recently presented a series of articles in a special issue on freshwater salinization in the journal Limnology and Oceanography Letterspublished last February.

    In this special issue, we focus on sodium chloride (NaCl), the same molecule found in table salt, as a key agent of freshwater salinization. We highlight a series of co-ordinated field experiments, conducted by researchers in North America and Europe, that have addressed the impacts of freshwater salinization on zooplankton (microscopic crustaceans) at a regional scale.

    Zooplankton are an ecologically critical group in aquatic food webs and are often used as indicators to detect environmental change due to their sensitive ecological tolerances.

    The main conclusions of these experiments are as follows:

    • Water quality guidelines in Canada and the United States (standards) do not adequately protect freshwater zooplankton, which could lead to an increase in the abundance of algae, which the zooplankton feed on. This is because when zooplankton abundance decreases, especially for large grazers such as Daphnia, phytoplankton can proliferate under conditions of reduced predation;
    • Salinization of freshwater systematically leads to a loss of abundance and diversity of zooplankton in all regions; and
    • Individuals of the same zooplankton species do not all exhibit the same tolerance to salinity. Thus, this variation may interfere with our ability to predict community-level responses. Water quality guidelines may therefore need to be adjusted to become more region-specific.

    A matter of regulation

    Many questions remain unanswered. However, what we do now know is that long-term water quality guidelines (Canada: 120 mg Cl⁻¹L⁻¹; United States: 230 mg Cl⁻¹L⁻¹) and in the short term (Canada: 640 mg Cl⁻¹L⁻¹; United States: 860 mg Cl⁻¹L⁻¹) for chloride concentrations are too high to protect aquatic life in Canada and in the United States. For reference, a pinch of salt in a pot of water corresponds to approximately 0.3 mg of Cl⁻¹/L⁻¹. In other words, adverse effects are observed at much lower concentrations. Regulations in Canada and the United States should therefore be reviewed. In Europe, the water quality standards for salinity for the protection of aquatic life in freshwater ecosystems are mostly absent.

    The importance of taking concrete action

    Water quality guidelines for the protection of aquatic life are generally established using laboratory tests (called toxicological tests) on a single species.

    However, aquatic habitats harbour a complex array of predators, prey, competitors, and pathogens, the interactions of which can limit our ability to predict the responses of communities and species to pollutants .

    Thus, the collective research published in this special issue also highlights the importance of understanding ecological responses in multi-species communities in natural settings to assess the responses of freshwater life to human impacts.

    Overall, we should develop alternative applications and technologies that are more sustainable and efficient.

    We also need to establish more appropriate water quality guidelines to improve controls on salts entering our freshwater environments to reduce adverse effects on aquatic life and the quality of our freshwater resources.

  • 20 Mar 2023 2:16 AM | Smart About Salt (Administrator)

    Can sugar melt snow like salt? Which other substances can? » Science ABC

    Going sledding, making snowmen, and having snowball fights are some ideal ways to enjoy winter weather. However, you might not feel the same way when that snow covers your driveway, roads, and roofs. It is frustrating and time-consuming to clear out all that snow!

    Salts can help us tackle these problems.

    Rock salt, also known as Sodium chloride or Brine, and other anhydrous salts like magnesium chloride and calcium chloride, are used in bulk quantities by the government to melt road snow during winter. The salts used for melting snow on pavement are commonly known as ‘Deicers’ or ‘Road Salts’. They cannot be consumed like edible salts.

    Water freezes at 00C, and at this temperature, ice and water, i.e., the solid and liquid states, are in equilibrium with each other. When we add salt (any salt) to water, it dissolves in it and causes a phenomenon called ‘Depression in Freezing point’.

    This is a colligative property shown by solvents like water. Hence, the water that was supposed to freeze at 00C  will now freeze at a lower temperature (say -100C), depending on the salt concentration. So, if the atmospheric temperature is 00C, snow will melt instead of remaining in its solid form.

    The snow during winter storms is not 100% solid. It is soft to the touch, which signifies that the water has not completely frozen. The deicers get dissolved in these small water cavities and melt the snow. A small concentration of salt is enough to melt a large chunk of snow. Road salts form a major commercial product in countries with annual snowy winters, like the USA, Canada, United Kingdom, etc. The United States annually utilizes NaCl and other Chloride-based road salts worth roughly 24 million dollars.

    Can Sugar Melt Snow?

    At the freezing point of water, molecules of water lose their kinetic energy and solidify, forming a crystalline structure. As more and more molecules are attracted, they become compact and develop a strong attraction due to Hydrogen bonding. As seen in the figure, there is a relative decrease in the intermolecular distance when water goes from liquid to ice.

    This intermolecular distance is disrupted when we add any soluble solutes, like salts. Molecules that dissolve in water overcome the attraction between water molecules and get squeezed between them. As a result, the attraction between like molecules decreases, and it takes even lower temperatures to solidify.

    Sugar, i.e., sucrose, readily dissolves in water, so it can also cause a depression in the freezing point of water. However, sucrose doesn’t dissociate into its constituent ions, but instead remains as an uncharged disaccharide. On the other hand, salts ionize into their constituent ions, e.g., MgCl2 –> Mg2+ + 2Cl, and easily displace themselves between water molecules.

    Depression in the freezing point depends on the number of solutes present in the solvent: the more solute particles, the greater the lowering of the freezing point.

    Therefore, although sugar can melt snow, it cannot do it as effectively as salts.

    Why Are We Looking For Alternatives?

    After the snow melts, it is cleared either by the steady stream of vehicles or the flow of water into the nearest drainage system. However, the problem is that the salt on the road can negatively impact the environment.

    Most road salts are chloride-based salts. Chloride is a nemesis for vehicles, as it initiates corrosion-induced degradation. Chloride absorbs moisture, thus speeding up the rate of corrosion.

    The salts that remain in the water enter nearby water bodies and can disrupt aquatic ecosystems. Water bodies near cities are usually freshwater resources like rivers, lakes, and ponds; if salts enter these reservoirs, they reduce dissolved oxygen (DO) and endanger aquatic life. Increased salinity results in a toxic algal bloom by killing algae-eating zooplankton.

    One might think that salts are everywhere in the environment, especially chloride salts, which are essential for living cells. Yes, this is true, but to give you some perspective, these salts are used by the millions of tons each year. Hence, the amount of salt entering the environment untreated is beyond permissible levels. Therefore, we need to look for alternative salts or snow-melting systems that cause less harm to the environment.

    What Are Some Other Alternatives?

    Commonly used chloride alternatives are:

    • Beet sugar
    • Glycols
    • Molasses
    • Corn-derived polyols like mannitol, sorbitol, maltitol
    • Hydronic, electric and infrared lamps.

    Brine salt is found naturally, while other chloride salts can easily be extracted from minerals. Hence, to minimize the effects of these salts, additives are added instead of bulk-producing new salts.

    These additives are bio-based, so they degrade easily in the environment. Beet sugar, glycols, and molasses have been proven to show good deicing properties. Agro-based additives, especially corn-derived polyols like mannitol, sorbitol, and maltitol, have proven to be suitable additives to brine salt, which bring about a good depression in the freezing point of water.

    Apart from chemicals, machines can also melt snow. Spraying steam and hot water on accumulated snow proves to be effective and eliminates the manual task of removing snow. Hydronic, electric and infrared lamps are found to do the same for pavement surfaces, sidewalks, and bridge decks.

    Finding alternatives for chloride salts has been challenging researchers, mainly for 2 reasons: cost and energy. The additives mentioned above are costly to produce in such bulk quantities and machines are energy-intensive tools. Thus, finding a perfect alternative that ticks all the boxes is an ongoing challenge.

    A Final Word

    Snow is melted by manipulating its freezing point depression, often through the use of soluble solutes like salts and sugars. The concentration and atmospheric temperature also play an essential role in the effectiveness of these deicers. Commercial NaCl deicer can’t melt ice below -100C. Hence, various salts and additives are added to melt snow in extreme temperatures, while having a less harmful environmental impact.

  • 09 Mar 2023 3:26 PM | Smart About Salt (Administrator)

    Having trouble finding road salt on the Avalon Peninsula? Here's why | CBC News

    Winter hasn't slipped away just yet, but some living on Newfoundland and Labrador's Avalon Peninsula have found it difficult to locate one of the season's hottest commodities — road salt.

    The culprit? Tens of thousands of faulty road salt bags, says Morgan Winter, vice-president of Avalon Coal Salt and Oil.

    The Bay Roberts company provides a lot of the province's salt, typically found at gas stations and grocery stores in large, bright orange bags.

    This year, Winter says, he thought he had his business's inventory in the bag. But it turns out he was sandbagged by the company's manufacturer.

    He says the company discovered in the fall that it had been supplied tens of thousands of faulty 10-kilogram bags. Winter estimates the faulty bags made up about 50 per cent of what the company ideally likes to have in its inventory.

    When the company went back to its supplier, says Winter, it discovered the lead time to get new salt bags would be longer than anticipated. Although the company also sells five-kilogram and 20-kilogram salt bags, Winter says the 10-kilogram bags are their best seller.

    "If I don't have a bag to put the salt in, that slows down everything," said Winter. "We pretty much sold through everything we had in inventory, I want to say, two or three weeks ago."

    "We don't operate that way. Normally we would have a 50 to 75 per cent cushion on what we would sell."

    For those on the hunt for salt, Winter says 20-kilogram salt bags may be available at large retailers and hardware stores, and he even suggests seeking salt from his competitors.

    The best places to go for salt are large building centres like Home Hardware, Kent and Home Depot, he said, as salt is likely in low supply at many gas stations.

    Winter looks at this year's supply shortage as a learning lesson, one that can help prevent future slip-ups.

    "We will be pre-ordering in April, and I would think we'll start ordering a two years' worth of inventory at a time just to get ahead of this problem."

  • 04 Mar 2023 3:46 PM | Smart About Salt (Administrator)

    Road salt impacts groundwater year-round - Canada News -

    To reduce hazardous winter driving conditions, highway departments turn to salt de-icers.

    Does road salt affect groundwater? If so, is there a lasting impact that can be measured?

    The Delaware Geological Survey is taking an in-depth look at groundwater quality.

    Rachel McQuiggan, a researcher at the University of Delaware, is monitoring storm water and groundwater at infiltration basins — large, shallow roadside pools that allow water to infiltrate the groundwater.

    Her 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.

    “Groundwater provides almost half of all drinking water worldwide,” says McQuiggan.

    “In central and southern Delaware, groundwater is the only source of potable drinking water. The results of our research should encourage best management practices for de-icer to protect groundwater resources.

    “Most storm water 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 storm water benefits from a natural filtering of contaminants as it infiltrates through soil, and contaminants dilute as that recharge mixes with existing groundwater.”

    She adds these basins 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.

    To evaluate the impact road salt had on groundwater quality, McQuiggan monitored the target infiltration basin from mid-May 2019 to mid-February 2022. Her team saw that geological complexity, such as differences in subsurface soil properties, influenced how salty storm water moved through groundwater.

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

    Chlorine is found deep within the Earth’s crust. It is known for forming neutral salts such as potassium chloride, calcium chloride and sodium chloride, also known as table salt.

    Outside of winter, storm water doesn’t contain much salt. It enters the basin and flushes sodium from the soil into the water. The study suggests a higher salt content can cause radium to enter the groundwater.

    “Climate can really impact the timing of how this all plays out. For example, if it’s a particularly dry spring and summer, the sodium takes longer to reach groundwater. 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.”

    There are other de-icers available, but they are not as effective as road salt. Each has its drawbacks. Sand is a popular option to increase traction and minimally affect groundwater, but it requires extra maintenance like street sweeping.

    “There are even carbohydrate de-icers like beet juice. However, most alternatives are used in conjunction with salt or acetate because those are so effective. Road safety is incredibly important.”

  • 02 Mar 2023 6:50 AM | Smart About Salt (Administrator)

    No salt brine on roads - Letters -

    n the last two weeks, we have had comparatively dry weather.

    There have been only a couple of light-snow days in the last week. So, why are the roads being heavily sprayed with toxic brine? What is the criteria for spraying this destructive (liquid)? Who makes the call? Was that person’s name on my municipal ballot?

    I certainly did not vote to have my driving curtailed by the threat of my personal vehicle being damaged by this stuff.

    The “safety” aspect of salt application doesn’t wash. Proper winter tires (not all-seasons) and slower driving will work without salt. It seems like the general public has it’s collective head in the sand when it comes to this issue.

    One’s vehicle is a large investment, whether you pay the price for a new vehicle or spend the time and money to maintain an older vehicle. I can understand there is a certain, large demographic in this valley that never keeps a “daily-driver” (vehicle) for more than three years, so the concern for vehicular salt damage is irrelevant. For the rest of us, this amounts to an unauthorized destruction of a personal asset.

    The spraying of brine has become extreme. The excuse trotted out is that brine application is a “prophylactic” measure, to reduce the ice/snow adhering to the pavement. Almost any dry day, those tankers are spraying brine on the roads in anticipation of ice. There is no snow. They get the same weather forecasts that we do. The next day, they are out again, spraying. Is it a quota system?

    There is a document from a partnership of the federal government, the provinces and municipalities, the Transport Association of Canada. The article is called Synthesis of Best Practices Road Salt Management, 1.0 Salt Management Plans. It is large and goes on at length about the appropriate application of salt, whether it’s rock salt or the more destructive cal/mag liquid de-icers.

    The article goes into depth about the destructiveness to the environment, bridges and road infrastructure. Of course, because it is a government initiative, there is no mention of the proven damage to personal vehicles. It also does touch on the damage to commercial vehicles.

    This document includes an education aspect for people who authorize, and operate the salt-application machinery.

    “Understand that chemical should not be applied to dry pavement where drifting snow is not sticking, unless it is necessary as part of a storm response strategy,” it states.

    We rarely get the conditions that qualify as a snow storm. What would normally be a dry road surface is wet with concentrated salt water.

    “Understand when to use, and not use specific chemicals, taking into account pavement temperatures, forecasts, time of day, traffic volumes etc.,” says the article.

    This situation came to a head last week, under sunny, dry skies on a dry road midday, while I was driving my 104-year-old Ford Model T into the Stevens Road roundabout at Westlake Road in West Kelowna.

    The salt truck entered the roundabout ahead of me to my right, and started spraying heavily right in front of me as it exited the roundabout to go south on Stevens Road. There was no snow or ice in the forecast for the next three to four days. I had to perform a fairly drastic maneuver to avoid the salt spray and drove over the roundabout, up the hill to Highway 97 and the perfectly dry pavement to finish my errands.

    Fortunately, the Model T’s high clearance made the manoeuvre easy. I insure this car year-round, but a large part of the winter, the salt-brine sprayers ruin what would be an otherwise enjoyable drive.

    There are considerable studies and documentation about the rapid destruction of vehicle systems, resulting from liquid-salting. Because it is a continuous “bath” of concentrated salt water, vehicles pick it up with their tires and completely soak every surface underneath.

    This stuff goes airborne and kills the effectiveness of windshield wipers and washer fluid. It gets into every crevice on the body (of vehicles).

    Windshield replacement shops are finding dangerous deterioration of the windshield recess and pinch weld areas. Comprehensive insurance does not cover the expensive repairs and resulting loss of vehicle use, while the damaged area is cut out, and replaced. The salt undermines the sealant under the windshield, and can result in the sudden detachment of the windshield.

    Because modern vehicles depend so much on the integrity of the windshield, the hidden damage compromises the structural integrity of the roof and can cause the airbags to deploy outward, instead of protecting the passengers.

    So much for safety, when the so-called safety initiatives that justify salt use cause such damage to vehicle structure, safety, electrical systems and visibility while driving.

    Andrew Kiesewetter, West Kelowna.

  • 02 Mar 2023 6:48 AM | Smart About Salt (Administrator)

    Scientific test kits give Muskoka volunteers tools to study road salt (

    Volunteers are testing to see how much road salt or chloride is draining as runoff into some Gravenhurst-area lakes.

    The volunteers, Citizen Scientist from the Gull and Silver Lake Residents Association and Probus Gravenhurst, are working with the Friends of the Muskoka Watershed to determine how road salt is impacting the Gravenhurst-area watershed. They are using scientific water quality testing kits provided by Friends of the Muskoka Watershed.

    Studies show that Gravenhurst Bay in Lake Muskoka and Jevins Lake have some of the highest chloride levels of the lakes tested in Muskoka. The low calcium levels in Muskoka’s recreational lakes means that all animal life is sensitive to road salt, and animal life in 20 per cent of the lakes is suffering from road salt.

    Neil Hutchinson, a volunteer director with FOTMW, has been studying local chloride levels and working with volunteers to determine how the chloride is entering the lakes. FOTMW has selected areas where water flows or drains into the lakes and has volunteers testing the chloride level.

    As there are no natural local marine salt deposits in Muskoka, and the lakes with elevated chloride levels all have major winter-maintained highways in their immediate catchments, road salt is the only logical salt source, according to an FOTMW report by Norman Yan.

    This is a pilot project, but FOTMW plans to roll out a larger program across Muskoka starting in the fall. Once data is gathered, to determine how chloride enters the lakes, the next step is to find solutions and modifications that can involve the whole community.

    “We couldn’t do this work without our volunteers,” said Hutchinson. “It is so important to have the community involved, and helping to make a difference.”

    Friends of the Muskoka Watershed is a charity that pairs action-based approaches with innovative science-based solutions to protect Muskoka watersheds.

  • 25 Feb 2023 6:57 AM | Smart About Salt (Administrator)

    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. 

  • 10 Feb 2023 6:28 AM | Smart About Salt (Administrator)

    Researchers Are Creating Road Salts That Aren't Terrible For the Planet (

    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.

  • 07 Feb 2023 7:30 AM | Smart About Salt (Administrator)

    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.

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