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  • 03 Feb 2020 9:35 AM | Smart About Salt (Administrator)

    The Ottawa River Keeper is raising an alarm about high concentrations of salt found in early testing of Ottawa area rivers and creeks.

    The River Keeper, Elizabeth Logue, said the non-profit organization has begun a winter road salt monitoring program aimed at establishing whether city road salt operations and other de-icing efforts by residents are having a detrimental impact on local waterways.

    The early results are already causing concern.

    "There are regulations that are made to determine the levels that are a problem for the environment," Logue said. "We can see concentrations higher than acceptable."


    This week, on the shore of a creek near Highway 417 off Pinecrest Road, Logue and biologist Katy Alambo scooped up buckets of water and used a device the size of a television remote control to test for "electrical conductivity," or EC. The more salt in the water, the stronger the EC.

    It's a preliminary test to see whether the water should be further analyzed by a lab.

    On this day, the EC levels were 50 per cent higher than the upper limit for acceptable.

    "It's concerning," said Logue, who says other samples in several locations around the city are showing similar findings, "It's an indicator we may be using too much salt."

    "High levels of salt concentrations can have affects on organisms," said Alambo. "Chloride is toxic to organisms when exposed to high concentrations."


    The high levels match some of the findings from a "Surface Water Quality Report" produced for the city's Environment and Climate Protection Committee in the spring of 2017.

    Ryan Polkinghorne, the city's program manager of stormwater management and environmental monitoring, said in a statement to CBC the report suggests "overall, median chloride concentrations in the Ottawa River remain well within water quality objectives."

    The report does note an overall trend between 2010 and 2014 of improving water quality on most criteria like phosphorous and copper, but there were two exceptions: E. coli and chloride.

    "Although chloride may be naturally occurring, there is evidence that the most likely source of the upward trend for chlorides is an increasing release of road salt," the report noted.

    The report noted several waterways where water samples showing high levels of chloride above Canadian guidelines for safe levels: samples taken from 2010-14 from Shirley's Brook near Hines Road showed 63 per cent of samples exceeded standards. At Still Water Creek, 92 per cent of samples exceeded standards. Pinecrest Creek and Nepean Creek also exceeded acceptable chloride levels in more than 80 per cent of samples.

    Among all the Ottawa River East tributaries as well as Ottawa River West tributaries sampled, half exceeded safe levels, and a quarter of Rideau River North Tributaries.

    Among its recommendations is a call to "continue with existing efforts to reduce salt use on city infrastructure/facilities as well as, on commercial private property."


    However, a statement from the city program responsible for salt management suggests its current practice hits the right balance between the need for public safety, and protecting the environment.

    "A de-icer is required to maintain roads to a bare condition, and the industry's primary deicing method is road salt," wrote Kevin Monette, the city's manager of operational research and projects.

    The city's goal is to minimize environmental impacts, while still maintaining the city standard, he wrote. At the same time, Monette said Ottawa is an early adopter of salt management best practices.


    The Ottawa River Keeper said its own testing comes in lieu of city testing in winter months.

    Logue said winter testing is critical as it captures the impact on water during peak periods when road salt is being used on Ottawa roads.

    Polkinghorne said the city is committed to water testing on "a suite of parameters on a monthly basis during ice-free conditions, as the ice conditions can present safety issues for staff."

    Since 2018, the city has partnered with the Rideau Valley Conservation Authority to monitor 170 waterways in the Ottawa areas. The RVCA said it is due to produce its first report, likely in 2021.

  • 24 Jan 2020 12:03 PM | Smart About Salt (Administrator)

    Cornwall’s roads department is planning to try using beet juice to keep the city’s roads ice-free as a way to cut down on the amount of road salt it uses.

    Road salt prices have skyrocketed over the past two years due to major production disruptions in 2018. The world’s largest underground salt mine in Goderich, Ont., had a 12-week strike while another mine in Ohio had several of its shafts flooded around the same time.

    The market still has not recovered, and road salt prices are 30 per cent higher than they were last year. Because of these prices, municipalities in Canada and the United States have been trying out alternative to ease their winter-control budgets. Part of that solution? Sugar beet juice.

    Just like how salt lowers the melting point of ice, the sugars in the beet juice have a similar effect. The beet juice is actually a kind of molasses produced as a waste product from sugar refinement. It can be mixed with water and some salt and sprayed on roads.

    It has been used in other municipalities with success, similar to other wet-application sprays, or de-icers— though many of these are brines of some sort, which still require salt.

    The City of Cornwall’s acting-division manager of municipal works, Paul Rochon, says the plan is to run a trial with the beet juice this winter to see just how well it works.

    “We are just waiting for some colder temperatures; we want to try it out when it’s good and cold outside. We’ve been very fortunate this year to have such mild temperatures so far this winter, but when the cold does come we will put it down on one of our major roads,” said Rochon. “We will let everyone know where we are trying.”

    Currently, Cornwall sprays its road salt with a calcium-chloride or magnesium-chloride solution while it is being spread on the roads to maximize the salt’s effectiveness. This is done after the snow has already fallen.

    The beet juice, in contrast, is sprayed on roads before a storm and works by preventing the ice from being able to bond to the road. The benefit of this is that the juice is non-corrosive to cars and spaying it down beforehand means that the city should need less salt to de-ice the roads after a storm.

    The beet juice is slightly more expensive the calcium-chloride or magnesium-chloride solutions, but the key question will be if it is effective enough to save money in salt costs.

    “Some studies have proven that we can use less salt, which is very expensive. So we are going to give it a test trial this year,” said Rochon.

    The trial will cost about only a few thousand dollars, the money for which will come out of the department’s current operating budget.

  • 24 Jan 2020 12:02 PM | Smart About Salt (Administrator)

    After enjoying the snowiest, coldest 10 days of the winter, Minnesotans once again proved we know how to handle weather. We can mock those less-hardy citizens in other parts of the country where a few inches of snow or temperatures below freezing mean catastrophe.

    But our friends to the north have an even better grip on winter.

    Between Christmas and New Year’s, our family enjoyed a weekend vacation in Winnipeg. We’ve visited Winnipeg before, as well as Ottawa, Toronto and Montreal. But all those trips were in summer.

    For those who haven’t visited, Winnipeg is a six-hour drive along interstates with little traffic. We planned to sample a number of unique restaurants and visit the Canadian Museum for Human Rights that opened in 2014. We couldn’t land reasonably priced tickets for a Jets game, but we did watch the Manitoba Moose (a team started 25 years ago as the Minnesota Moose) who play in the American Hockey League. For those on a budget, three U.S. quarters get you a $1 of Canadian cash.

    We arrived in Winnipeg late on Friday afternoon and soon we noticed two curious scenes.

    First, we noted that a majority of vehicles lacked hubcaps. My oldest daughter speculated that perhaps Winnipeg suffers from a high incidence of hubcap thefts.

    And we remarked, the cars were dirty. Unlike Minnesota vehicles, crusted with dried road salt, dirt coated our Canadian neighbors’ cars.

    The answers to these puzzles were not larceny or lust for mud, but Canadians adapting to winter driving.

    Canada is one of the coldest places in the world – only Russia, Greenland and Antarctica are colder. So, coping with winter is serious business.

    First the hubcaps. When the temperature drops, Canadians bolt on their winter tires and don’t bother snapping on hubcaps.

    While Quebec is the only province where it’s mandatory for every vehicle to have winter tires, Manitoba and other Canadian provinces recommend installing four winter tires when the mercury drops below 45 degrees F.

    Winter tires have replaced what used to be called snow tires. The difference is in the tread pattern. Snow tires had deeper grooves for gripping the snow, but the rubber got hard when it was cold and didn’t work so well on ice. Today’s winter tires have a tread designed to grip both snow and ice by remaining supple in the cold.

    Since 2008, it’s been a law throughout the province of Quebec for all motorists to have four winter tires installed on their vehicle from Dec. 15 to March 15. These tires must be marked with the peakedmountain-with-a-snowflake symbol, which guarantees the tires have been certified to meet snow traction performance requirements. Getting caught without winter tires risks a fine of $200 to $300.

    Now about those brown cars. Canadians go easy on the salt. They are not only concerned about the environmental damage of salt, there’s a matter of chemistry.

    Salt is only effective to around zero and after that the only other tool to help keep cars on the road is sand. Sand is the main treatment for city streets and less-traveled roads.

    Instead of salt, Winnipeg is testing spraying beet juice on slippery city streets this winter.

    The benefit from using beet-based melting products is that it reduces the chloride loading on streets and the environment. City officials say beet juice works to about minus 22 degrees F. Winnipeg only uses salt on main roads, with brine and sand used on other streets. Two small problems with beet juice…a foul order and staining.

    The state of Minnesota and many cities use a commercial product to enhance brine applications … but no beet juice.

    While your friends vacation in Arizona or Florida this winter, consider heading north and test your winter coping skills with the pros.

  • 24 Jan 2020 10:22 AM | Smart About Salt (Administrator)

    Road salt is arguably a life-saving necessity during Canadian winters, but new research shows it may also indirectly boost the mosquito population come summertime.

    According to a study published recently in the journal Frontiers of Ecology and Evolution, all that salt is leaching into roadside storm ponds, where both mosquito and dragonfly larvae grow.

    Rosalind Murray, a post-doctoral fellow in biology at the University of Toronto and one of the study's authors, studied storm ponds in the GTA with her research team.

    These man-made ponds are meant to catch road run-off before it drains into the watershed, but they're also full of tiny life. With no fish or frogs present, the wingless dragonfly larvae, which measure up to three centimetres in length, are the apex predators, and have a voracious appetite: a healthy one consumes an average of 11 mosquito larvae in two hours.

    "But the salty dragonflies — the ones that were exposed to the highest level of salt for the longest amount of time — were eating significantly fewer mosquito larvae," Murray told the CBC's Ottawa Morning — as few as seven every two hours.

    "That might not seem like that big a difference, but if you think about how many ponds and how many dragonflies, this can have a huge impact on ... how many mosquitoes they're actually consuming."

    The salt appears to have little effect on the hardy, adaptable mosquito larvae, leaving the population to thrive.

    "If you have a very salty environment that has killed off a lot of the potential predators for the mosquitoes, then you might be exposed to even more mosquitoes," Murray said.

    But dragonfly larvae also feed on each other, and salty ones are slower to heal, she said.

    "Dragonfly larvae are hugely cannibalistic, so they might pull off a leg. When they're exposed to high levels of salt … they're not as quick at recovering from these wounds."

    The researchers followed the salty dragonflies into adulthood, and found they were less healthy. As well as healing more slowly, the insects were also found to be more vulnerable to infection.

    For humans, this poses a dilemma: using road salt in the wintertime means more mosquitoes in the summertime.

    Murray said she's not advocating for an end to road salt, but until a healthier alternative is found, she wants municipalities to consider the impact excessive amounts are having on the ecosystem.

  • 23 Jan 2020 7:02 AM | Smart About Salt (Administrator)

    I read with interest the Jan. 16 article regarding the use of salt brine in St. Clair Township. Perhaps I can provide some additional information. I have been involved with the use of winter liquids for road use for the past 30 years in conjunction with the MTO, regional, and municipal governments.

    The application described in the article is an operation called “anti-icing” or “direction liquid application”. This application of liquid directly onto the road surface is conducted prior to a storm often in good weather based on advanced weather forecasting. It has been proven that this technique will prevent the bonding of ice and snow to the road surface, making it eight times easier to remove compared to just traditional plowing and salting.

    The liquid is applied by equipment that utilizes spray systems that are computer controlled, so the application is uniform, typically in the range of 100 litres per lane kilometre, which is actually quite a small amount.

    I have no doubt that the St. Clair Township works department is applying this brine correctly.

    This is not a new technique. It gain widespread use across Canada after the publication by Environment Canada of The Code of Practice for the Environmental Management of Road Salts, developed in 2004 to assist municipal and provincial road organizations to better manage their use of road salts in a way that reduces the harm to the environment while maintaining roadway safety.

    This code of practise identified three major Best Practices one of which was the use of winter liquids (brine) including “anti-icing”. This is now commonplace and used across Ontario including major highways of the MTO, Toronto, Ottawa, London, Kitchener, and numerous others.

    I personally think that St. Clair Township should be applauded for using modern techniques that provide better road safety while protecting our environment.

    Mark Slotwinski


  • 16 Jan 2020 7:25 AM | Smart About Salt (Administrator)

    Consulting engineers at GHD have worked with Melfer Construction and the municipal government of Guelph, Ont., to build a new 18,600-m2 snow storage pad that will help reduce the local environmental impact of road salt.

    Nearly 12 times the size of a hockey rink, the pad was built from approximately 3,500 m3 of recycled concrete and asphalt, with the support of a $3.5-million grant from Infrastructure Canada’s Clean Water and Wastewater Fund. It sits near Guelph’s existing wastewater treatment facility on Wellington Street West.

    “Throughout winter, the city clears 500 to 2,000 truckloads of snow, ice, sand and salt from roads, bike lanes and sidewalks,” explains Doug Godfrey, Guelph’s general manager (GM) of operations. “In some cases, such as residential streets, the snow is simply cleared out of the way. In other cases, such as large parking lots, bridges and some downtown streets, it has to be scooped up and moved elsewhere.”

    In the past, the city simply used an empty field near Wellington and Imperial Roads to store this snow. Each spring, it would melt directly into the sandy soil below and around the field.

    “The pad is equipped with a drainage system and low-permeability lining to reduce erosion and protect the environment,” explains Prasoon Adhikari, P.Eng., an environmental engineer for the city. “Now, as snow melts, it’s collected and directed to a stormwater management pond, where it’s slowly filtered, before making its way into nearby wetlands.”

    As part of the project and following an environmental impact study, city staff planted salt-resistant native trees and shrubs throughout the site, which also features a new weather station and commercial net-metered solar panel system.

  • 27 Dec 2019 8:13 AM | Smart About Salt (Administrator)

    While Americans may dream of a white Christmas, living with snow the rest of the season is driving a nightmare salt habit.

    Each year, Americans spread more than 48 billion pounds of salt on roadways to ward off the effects of winter weather. But it comes at a cost: De-icing salt degrades roads and bridges, contaminates drinking water and harms the environment, according to a slate of scientists expressing growing alarm.

    “The issue of road salt has been out in front of us for decades but has received very little attention until the past five years,” said Rick Relyea, a biological scientist at Rensselaer Polytechnic Institute near Albany, New York. “Then we see, my goodness, it is everywhere, and it is a growing problem.”

    It’s a problem that’s growing exponentially.

    The country used about 164,000 tons of road salt in 1940, U.S. Geological Survey data shows. It broke 1 million tons in 1954, 10 million in 1985, and now averages more than 24 million tons a year.

    While salt helps keep roads clear in winter, it doesn’t just disappear with the snow. Some melts into rivers, lakes and even water supplies. The portion that remains on roadways eats away at pavement and bridges. It does the same to pipes that carry drinking water, causing lead contamination in some places. Too much salt in the environment can kill small organisms and change the sex of frogs.

    “We have only recently begun to recognize the serious long-term consequences of excessive road salt use,” said Marc Edwards, a Virginia Tech corrosion expert who helped uncover the lead drinking water crisis in Flint, Michigan.

    The Northeast is a top contributor. ClearRoads, a national consortium that researches and promotes winter road maintenance solutions, tracks how much road salt state governments use every year.

    At the top are five New England states that used the most salt per mile of road lanes over the past four years: Rhode Island (44.2 tons), Massachusetts (34.6 tons), New York (28.0 tons), New Hampshire (25.1 tons) and Vermont (23.3 tons).

    Connecticut and Maine also fall in the top 10, while Pennsylvania ranks 13th, Maryland 16th and Delaware 23rd. New Jersey hasn’t contributed data since 2014-15, but the 42 tons it used per mile that year would place it near the top.

    And that’s just the salt we know about. ClearRoads data tracks only state governments; salt used at private businesses and parking lots, on residential driveways and sidewalks, and by some cities isn’t captured. Many experts believe private industry could be using more salt than government, but no one’s tracking that.

    More road salt, more problems

    In the U.S., using salt to de-ice roadways is a technique dating to at least the late 1930s. There’s some mystery as to who did it first. Some say Detroit, others New Hampshire.

    There’s less mystery about the chemistry. Road salt typically consists of sodium and chloride. While sodium is less water soluble and lodges in soil, the vast majority of chloride washes away with the rain.

    Given the amount of salt used on roads, that’s a real problem, said Hilary Dugan, a professor of integrative biology at the University of Wisconsin-Madison. A 2017 study by her team found that nearly half of the 284 freshwater lakes in their sample in the Northeast and Midwest had undergone “long-term salinization.” One in 10 of them reached a threshold where scientists worry about impacts on aquatic life.

    In 2017:It’s so cold out, a dog froze, sharks died and road salt is useless

    Road salt alternatives?:We use millions of tons of salt to melt ice from roads. Is there a better way?

    Making matters worse, Dugan’s team found that chloride levels in lakes rose when just 1% of adjacent land was developed. More than a quarter of large lakes nationwide fit that profile, and the problem is worse in crowded states such as Rhode Island, where 83% of lakes are urban.

    “It was just so obvious that when a lake was near any kind of urban environment, the chloride concentrations tended to be going up,” Dugan said.

    Relyea studies what that means for aquatic life. Even moderately salty waters can kill zooplankton, the tiny aquatic creatures at the bottom of the food chain that he said “help make a lake function properly.” Their absence can lead to worsening algae blooms.

    At higher concentrations, Relyea’s work shows salt can alter the sex of tadpole populations, making them 10% more male. It also can stunt the growth of fish, like rainbow trout, leaving them more vulnerable to predators. What this means for wildlife up the food chain needs more study.

    “There’s much less out there on what (salt) does to ecosystems,” Relyea said. “There are all kinds of potential cascading effects.”

    ‘Catastrophic’ risks from road salt

    If sex-changing frogs don’t concern you, this might: A Washington State University professor estimates the country spends $5 billion a year on infrastructure damages caused by road salt – and it might not nearly be enough.

    Due to its chemical properties, road salt can exacerbate the damage roads already suffer each winter when they repeatedly freeze and thaw. The effect expands and cracks the surface, said Xianming Shi, a professor of civil and environmental engineering who wrote a book on the subject, “Sustainable Winter Road Operations.”

    Shi called the effects on concrete bridges especially “shocking.”

    That’s because road salt, particularly an alternative variety of magnesium chloride, can slowly leach calcium out of concrete in bridges, as well as roads and sidewalks.

    “It’s like when people age, their bones lose calcium and get brittle and are more likely to crack,” Shi said. “It’s a very similar situation with the concrete.”

    While working with the Oregon Department of Transportation, Shi’s analysis found that some bridge decks, even though they were highly rated upon visual inspection, had in fact lost 40% of their strength. At the very least, Shi said, that means expensive maintenance may be needed more frequently.

    At worst? “It means the load-bearing capacity could be comprised,” Shi said, which could lead to “some catastrophic failures.”

    “Unfortunately,” he added, “we may not see any visible symptoms before it is too late.”

    Corroding water pipes

    Motorists may be more familiar with another chemical trait of road salt: its corrosiveness. Chloride can eat away at a car’s undercarriage or any other exposed metal and cause corrosion and rust. A study by AAA found road salt could be costing car owners as much as $3 billion annually in repair costs.

    For the same reason, road salt threatens pipes that carry drinking water, scientists say. When chloride levels outnumber other specific substances in water, they corrode metal, and toxic lead can flake off into drinking water.

    A federal study last year found U.S. monitoring stations in snowy and urban areas had higher chloride levels, and that as they increased, so too did the chance a nearby water system had violated federal lead standards.

    High chloride ratios in the Flint River contributed to Michigan’s lead drinking water crisis, and the same problem impacts smaller systems across the country as well, said Edwards, the expert who helped uncover Flint’s drinking water problem.

    In 2015, he consulted with public works officials in Brick, New Jersey, and found that road salt contributed to corrosion and high lead levels in the township’s drinking water. Once identified, proper adjustments were made at the water treatment plant to fix the problem.

    The problems encountered in Brick could occur in any of the thousands of public water systems across the country where road salt is used, Edwards said, adding that local water departments often don’t understand the risks of high chloride levels.

    “The Romans allegedly salted the earth to vanquish their enemies, and we now do the same to ourselves at a once unthinkable scale,” Edwards said.

    Salty solutions

    America’s addiction to road salt – the “acid rain of our time” – can be cured, said Eric Siy, the executive director of The Fund for Lake George, a nonprofit supporting scientific efforts at the lake in upstate New York.

    Siy, who has partnered with IBM, Relyea, and local governments to address the problem, said the Lake George region has gone high-tech, implementing best practices that others can model.

    Local towns now use “live edge” snowplows that conform to the shape of the road and can significantly reduce salt use. Salt trucks use GPS and special software to track routes and salt dispersal, increasing efficiency. Localized weather forecasts help anticipate needs so that trucks using a brine solution can pretreat roads and reduce overall salt use.

    Siy said they’re already seeing results, with salt use in some plow trucks falling by more than 40%. Following Siy’s model, the tiny town of Hague, New York, reduced its salt use by 22% in two years, saving $38,000.

    “We’re not putting anybody on Mars here,” Siy said. “We’re simply reducing the use of salt.”

    Economic arguments are crucial to getting buy-in, said Laura Fay, a research scientist at Montana State University’s Western Transportation Institute, who has been pushing states and local governments for more than a decade to make similar improvements.

    “Maybe your state budget has been decreasing every single year,” Fay said. “So you’re trying to do the same or a better job ... with less money. That’s honestly what a lot of these agencies are facing right now.”

    ClearRoads data shows winter maintenance is expensive. New York tops the list in both overall costs ($373 million a year from 2015-18) and cost per lane mile ($8,451). Pennsylvania is second in total costs at $246.8 million, while four New England states round out the top five in costs per lane mile: Massachusetts ($7,233), Vermont ($4,967), New Hampshire ($4,815) and Maine ($4,148).

    Fay recommends a few simple steps to road crews to limit salt use and its impacts: Cover salt piles to protect them from precipitation and calibrate equipment to ensure proper salt distribution. Then, they can consider new approaches like the ones in Lake George.

    While return on investment varies, both Siy and Fay say most solutions pay for themselves within several years.

    Tackling the use of road salt by private companies poses a bigger hurdle, as the practice is almost entirely unregulated. Some states are trying, such as New Hampshire, which in 2013 introduced a program that trains private operators on best practices in exchange for liability protection.

    But the cheapest fix to America’s unhealthy road salt diet is also the most elusive: Reducing the public’s demand for clear roadways.

    “We as a driving public need to change our expectations to something closer to reality,” Fay said. “If you don’t need to drive to work, or the movies, or the mall, then don’t go.”

  • 20 Dec 2019 7:04 AM | Smart About Salt (Administrator)

    Many lakes around the Twin Cities are becoming so salty from winter road maintenance that, within three decades, they will no longer support native fish and plants.

    The lakes were included in the first study of freshwater chloride contamination across the northern region of the country, an area that has one of the highest density of lakes on earth. The researchers found that lakes showed steadily rising concentrations of chloride even with just one percent impervious land cover around their perimeters.

    The Twin Cities turned out to be among the saltiest.

    “One of the most impacted areas is Minneapolis and St. Paul, where you have dozens of small lakes,” said Hilary Dugan, the lead researcher and a limnologist at the University of Wisconsin, Madison. “The smaller the lake, the more easily you load it with salt.”

    Altogether, researchers analyzed the salt histories of 371 lakes in 10 northern states and Ontario, Canada — 62 of which were in the Twin Cities metro area. The study was published Monday in the Proceedings of the National Academies of Science.

    The study could provide new guidance for environmental campaigns in many northern states, including Minnesota, to use less salt. While many of those efforts focus on road and street agencies like MnDOT, Dugan said homeowners and private businesses are to blame for about half the salt used each winter. And no one knows how much they are using.

    “When you put down salt on the sidewalk you should be thinking of teaspoons — not cups,” she said. “All you need is a few crystals to work effectively on ice.”

    Minnesota’s official list of impaired waters already includes 45 water bodies polluted with chloride, where the high concentration of roads, sidewalks and parking lots get about 349,000 tons of road salt a year. The Mississippi River in the metro area is not yet polluted enough to violate federal standards, but a recent report showed that salt concentrations, mostly from road salt, have increased 81 percent since 1985.

    “That’s a dramatic increase in any kind of contamination,” said Brooke Asleson, who manages the metro area salt reduction project for the Minnesota Pollution Control Agency.

    Groundwater in the metro area is also affected, according to the Minnesota Pollution Control Agency, with almost a third of the monitoring wells in the area showing enough salt to affect aquatic life, and almost as many with enough to affect the taste of drinking water.

    The state has been fighting the problem for years, and many local governments have succeeded in reducing their use of salt thanks in part to the MPCA’s to educate municipalities and property owners on how to use less without compromising safety. The University of Minnesota cut its use by 41 percent, and the city of Waconia has cut it by 70 percent.

    The legal pollution standard for salt set by the Environmental Protection Agency is 230 milligrams per liter. And that amounts to one teaspoon per five gallons of water.

    A permanent pollutant

    Dugan and her co-researchers from across the country conducted the study in an effort to develop a national picture of salt contamination in water. They used all the available data they could find on lakes that have been monitored long term. They found 371 that were larger than 10 acres with enough data, including a significant number in Minnesota.

    They combined that with climate data and land use data that identified paved and impervious surfaces.

    They saw a clear picture that tied the amount of pavement with salty lakes. Any lake with one or more percent of paved surface around its border increased the likelihood of long-term salinization, she said. And 27 percent of all the lakes in the country have at least that much around their perimeters. It means, she said, that if current trends continue many of them will no longer be able to support aquatic life by 2050.

    A Minnesota Pollution Control Agency study of briny lakes in the Twin Cities looked at the relationship another way, Asleson said. It found that the urban lakes that exceeded the federal pollution standard were always found in watersheds with 18 percent road densities or greater. That covers most of the metro area, but also urban watersheds in towns like Austin, Rochester and St. Cloud, and provides a road map for where lakes are at greatest risk, she said.

    Dugan found that lakes with a 500-meter perimeter of trees or natural vegetation were largely protected from salt, she said, at least for a while. Those lakes, mostly in the wooded areas of the northeast part of the country, showed low or oscillating trends in chloride.

    Still, a healthy perimeter of natural landscape is most likely a temporary solution, she said, because no matter where it goes, salt is permanent.

    “Road salt is not going to be removed,” she said “It’s either stored in the soil or ends up in the water.”

  • 20 Dec 2019 7:03 AM | Smart About Salt (Administrator)

    Road salt runoff threatens US, Canada lakes: study

    Salting of roads in winter helps drivers navigate snow and ice, but the runoff may be irreparably damaging freshwater lakes in the United States and Canada, researchers warned Monday.

    Most of the 371 North American freshwater lakes in the US Northeast and Midwest and Ontario province are showing an increase in salinity from chloride runoff, according to a study published in the journal Proceedings of the National Academy of Sciences.

    And if the trend continues it could doom aquatic life and reduce water quality, limiting the supply of drinking and irrigation water, the researchers said.

    “The picture is sobering,” said lead author Hilary Dugan, a freshwater specialist at the University of Wisconsin-Madison.

    “We compiled long-term data, and compared chloride concentrations in North American lakes and reservoirs to climate and land use patterns, with the goal of revealing whether, how, and why salinization is changing across broad geographic scales,” Dugan said in a statement.

    “For lakes, small amounts of shoreline development translate into big salinization risks.”

    Each lake studied was larger than four hectares (0.02 square mile) and had at least 10 years of chloride data.

    The majority (284) of the lakes were located in the North American lakes region that includes 10 US states — Connecticut, Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New York, Rhode Island, Vermont, and Wisconsin — as well as Ontario province.

    The use of road salt to keep winter roads navigable has been rising since the 1940s. The researchers determined that each year, some 23 million metric tons of sodium chloride-based de-icer are applied to North American roads.

    – Underestimated problem –

    Much of that road salt washes into nearby water bodies, becoming a major source of chloride pollution to groundwater, streams, rivers and lakes.

    To measure the quantities of road salt applied to roadways and other impervious surfaces, such as parking lots and sidewalks, the researchers evaluated road density and land cover within a 100- to 1,500-meter (0.06-0.09 mile) buffer around each of the study lakes.

    Their findings were clear: roads and other impervious surfaces within 500 meters of a lake‘s shoreline were a strong predictor of elevated chloride concentrations in the water.

    When the results of the study are extrapolated to all lakes in the North American lakes region, some 7,770 lakes may be at risk of rising salinity.

    If the escalation in salinization continues, it said, many lakes will exceed in the next 50 years the aquatic life threshold criterion for chronic chloride exposure set by the US Environmental Protection Agency of 230 milligrams per liter.

    According to the study, 14 lakes are expected to exceed the EPA standard by 2050, and 47 are on track to reach chloride concentrations of 100 milligrams/liter during the same time period.

    “These results are likely an underestimation of the salinization problem, as a number of regions with heavy road-salt application, such as Quebec or the Maritime Provinces of Canada, had no long-term lake data available,” said co-author Flora Krivak-Tetley, a graduate student at Dartmouth College.

    High chloride levels in lakes have been shown to alter the composition of fish, invertebrates, and the plankton that form the base of the aquatic food web.

    That can reduce aquatic species and, in extreme cases, salinization can cause low oxygen conditions that smother aquatic life and reduce water quality, the study noted.

  • 20 Dec 2019 7:02 AM | Smart About Salt (Administrator)

    As Canadians, we spend much of our time walking in a winter wonderland — yet one researcher at the University of Saskatchewan suggests we remain in the fog on snow and ice.

    "It's exciting how little we know, in a way," said Tara Kahan. "Water is everywhere — it's so important to us, our lives, [but] when it's frozen, we don't know a lot about it."

    Kahan, a professor at the University of Saskatchewan and the Canada Research Chair in Analytical Environmental Chemistry, has already spent more than a decade studying snow and ice, with an emphasis on what happens to pollutants trapped in a frozen state.

    "We are used to pollution in lakes, rivers and stuff like that. All those pollutants can also end up in snow and ice, but what happens to them might be different," Kahan said.

    Frozen fossil fuels 

    Kahan is focused on pollutants that come from fossil fuels. She cites the example of benzene, which is sometimes found in high concentrations in snow and ice in places like gas stations, areas where hydraulic fracturing is used to search for oil and gas, or in busy shipping lanes.

    In water, benzene does not react to sunlight. In ice, Kahan said it's a much different story — everything speeds up.

    "This could be a really good thing," she said. "For example, if there's an oil spill and they're reacting really quickly with the sun shining on that snow, maybe it's cleaning [the pollutants] up.

    "But on the other hand, they could be making something more toxic than what they started with, in which case this fast reaction would be bad. But we don't know yet."

    Given Kahan's academic commitment to snow and ice you might imagine her trekking to icy and remote regions seeking out pristine snow to sample, but she admits she "doesn't like to be cold."

    So her work is done methodically in a laboratory at the U of S — a lab full of ice cube trays.

    Tip of the iceberg 

    As Kahan slowly unlocks the chemical mysteries of snow and ice, the findings will be enhanced by existing computer models to hopefully predict what will happen to the pollutants she's studying. 

    That should help to shed light on some very important questions, she says.

    "We'll be able to just put this data into the model and then predict whether things are going to be good or bad — whether we need to worry, or whether we're really going to be remediating things and cleaning up the snow and ice."

    Kahan said that improved understanding of the chemical reaction of pollutants trapped in snow and ice will become vital in trying to mitigate environmental damage in fragile ecosystems.

    "The Arctic, actually, is a huge concern because as the winters warm … we're expecting a lot more shipping traffic. There's going to be a lot more pollution there."

    While the fog may lift on the issue of pollutants, Kahan doesn't think her work in understanding all the mysteries of snow and ice will ever be done, because there are so many things she would like to explore — topics like "sea ice, or ice that has road salt in it," she said.

    Kahan is all in on ice — as long as she doesn't have to spend too much time in the cold.

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