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Earth Science

Road Salt Works. But It's Also Bad for the Environment. (nytimes.com) 128

Posted by msmash from the closer-look dept.
As snowstorms sweep the East Coast of the United States this week, transportation officials have deployed a go-to solution for keeping winter roads clear: salt. From a report: But while pouring tons of salt on roads makes winter driving safer, it also has damaging environmental and health consequences, according to a growing body of research. As snow and ice melt on roads, the salt washes into soil, lakes and streams, in some cases contaminating drinking water reservoirs and wells. It has killed or endangered wildlife in freshwater ecosystems, with high chloride levels toxic to fish, bugs and amphibians, according to the Environmental Protection Agency. "It's an issue that requires attention now," said Bill Hintz, an assistant professor in the environmental sciences department at the University of Toledo and the lead author of a recent research review published in the journal Frontiers in Ecology and the Environment.

"There's plenty of scientific evidence to suggest that freshwater ecosystems are being contaminated by salt from the use of things like road salt beyond the concentration which is safe for freshwater organisms and for human consumption," Dr. Hintz said. Salt has been used to de-ice roads in the United States since the 1930s, and its use across the country has tripled in the past 50 years, Dr. Hintz said. More than 20 million metric tons of salt are poured on U.S. roads each winter, according to an estimate by the Cary Institute of Ecosystem Studies in New York, and the environmental costs are growing. Still, little has been done to address the environmental impact of road salt because it is cheap and effective, said Victoria Kelly, the environmental programming manager at the Cary Institute. By lowering the freezing temperature of water, salt prevents snow from turning to ice and melts ice that is already there.
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Road Salt Works. But It's Also Bad for the Environment. More

Road Salt Works. But It's Also Bad for the Environment.

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  • Moderation is key (Score:3)

    by Kernel Kurtz ( 182424 ) on Friday January 07, 2022 @04:53PM (#62153017)
    Road salt absolutely has place in making streets safer. When there are puddles on the road at -15C you know they are using waaay too much of it.

    • In Michigan they salt the roads like crazy. Throughout most of the state, the roads melts during the day, and freezes at night. You can drive home in the afternoon pretty comfortably most days, but morning commute is dangerous. The freezing-thawing, salt, and a miniscule road budget makes the roads there pretty much a wreck. Watching tax dollars go into repairing the roads always felt like throwing good money after bad. Long term it would have been cheaper to lay down some railroad tracts in the few metropo

      • Tire chains and autosocks are probably a better solution for grip, at lower temperatures. We use them in Big Bear every year. They should do the same back East.

        • Re: (Score:3, Interesting)

          by FuegoFuerte ( 247200 )

          Chains are great for hills/mountains, but not so great for the flat parts of the country where a bit of "pay attention and slow the F down" will do just fine, which describes most of the midwest/east. With chains, one has to slow WAY down (or suffer a really harsh ride), and they tear the hell out of the pavement, especially in areas where you're switching back and forth from snow to bare/wet pavement and back.

          Not to mention, with chains there's always the issue of them breaking and wrapping around axles/b

          • Re: (Score:2)

            by PPH ( 736903 )

            Studded tires get put on and taken back off once a year. Unless you have road ice during that entire period, they eat the hell out of pavement.

            Tire chains get put on when needed. And then taken right back off as soon as possible.

            With chains, one has to slow WAY down

            That's a benefit, not a drawback.

          • Chains are great for hills/mountains,

            They also ain't magic. I went to live in the US with zero experience of driving on snow and ice. After a few years there I became acutely aware of how bad the average driver on snow and ice is in areas which don't regularly experience it. I also remember driving straight on a mountain road in a snowfall and doing a nice, gently, utterly uncontrolled 180 spin with chains. Fortunately the twat in an SUV tailgaiting me had just enough grip to swerve out of the way.

      • Re:Moderation is key (Score:4, Informative)

        by theshowmecanuck ( 703852 ) on Friday January 07, 2022 @05:44PM (#62153327) Journal

        In Manitoba where it gets really cold every winter, they don't even bother with salt because of the thaw freeze scenario you describe. They only use sand to add grit to the road for traction. Where many places have salt trucks they have sand trucks (at least while I lived there). Same kind of truck, different load. Mind you, the colder you get the more traction you get on snow (it's drier). You know spring arrived when the city road cleaning trucks are out cleaning up the sand drifts.

        • In Manitoba where it gets really cold every winter, they don't even bother with salt because of the thaw freeze scenario you describe. They only use sand to add grit to the road for traction. Where many places have salt trucks they have sand trucks (at least while I lived there). Same kind of truck, different load. Mind you, the colder you get the more traction you get on snow (it's drier). You know spring arrived when the city road cleaning trucks are out cleaning up the sand drifts.

          I live in MB and I actually worked for COW Public Works for many years driving plows and spreaders before I moved into IT. Trust me, we use a lot of salt.

          • I lived in Winnipeg for 10 years from mid 80s to mid 90s. I never saw salt used. I also know from looking in the engine compartment of cars that there was almost no salt on the road. No rust, no corrosion. You could always tell when a used car was from Ontario because they use salt everywhere. When you open the hood there is corrosion everywhere from wet salt covered roads splashing up under. The rule was never buy a car where you saw that because you knew the body would like be fucked. Cars from the prairi

            • Well I can assure you that from the late 80s and all through the 90s I personally spread untold truckloads of salt on Winnipeg roads as a city Streets Maintenance employee. I'm completely unsure how you could have missed roads that are slush covered when the temperature is below zero, nor the fine white residue it leaves on the paint when it dries after driving though said slush. The general rule is that from 0 to about -7C, salt is used on regional streets, and below that temperature it is sand (treated
        • The town where I recently moved to seems to use mainly sand. And the locals all know to slow down and drive dainty in the winter. And people from elsewhere expect salt, and drive like normal, until they learn the hard way.

        • Re: (Score:2)

          by Rhipf ( 525263 )

          Manitoba winters are usually colder than the temperature where salt is effective. That is probably more of a reason for them using more sand than worry about freeze/thaw cycling. Salt can be effective to ~-20C but it would take a lot of salt at that temp. Effectively salting doesn't really do much good below ~10C.

    • Re: (Score:2)

      by DarkOx ( 621550 )

      umm, no that is absolutely wrong. Either use enough to melt the ice and made the road safe for travel or you are just dumping harmful salt all over the place and not even achieving the desired effect.

      • Either use enough to melt the ice and made the road safe for travel or you are just dumping harmful salt all over the place and not even achieving the desired effect.

        That is what I said.

    • Re:Moderation is key (Score:4, Insightful)

      by tragedy ( 27079 ) on Friday January 07, 2022 @05:13PM (#62153149)

      Road salt absolutely has place in making streets safer. When there are puddles on the road at -15C you know they are using waaay too much of it.

      It does make the streets safer, but even if people think that offsets the environmental damage, does it offset the economic damage? Road salt causes tens of billions of dollars (hard to pin down exactly, I tried to find good numbers for the number of cars in areas that use road salt, how many years it takes off the life of the car, actual value of those years of car life to the consumer and I came up with about $60 billion, but it could be a fair amount more or less) of damage to cars, for example. Then there's all the road damage the salt causes (it gets into cracks, crystallizes and expands doing far more damage than ice). If you factor in all the external costs, alternatives like heated roads may be competitive.

      • It does a lot of damage, absolutely, I'm not arguing. Not just to lakes and rivers as runoff, but to the streets themselves where it seeps into cracks and rusts the reinforcing steel, and to vehicles themselves. Lots of older vehicles here that are still mechanically sound, but are no longer roadworthy because the bodies are rusted out beyond repair.
    • Salt doesnt work below 17F. You gotta use calcium chloride to get down to below 0 temps. Thats much costlier and usually not done by cities. Its concrete safe though.
      • We were using CMA as a pre-wetting agent and regular salt when I left public works in 2002.

      • According to TFA, it's the chloride that's the problem. It doesn't matter what metal it comes with (apparently). Here's an idea! Start using plutonium chloride! It would be self-heating, plus keep the melt from freezing!

        • Not sure why NaCl eats through rebar and pits concrete where CaCl does not. It might gave something to do with the secondary reactions. Cl will eventually bind with another element to avoid being a free ion. Im not a chemist, but CaCl works at lower temps and less damaging to concrete and its rebar.

      • Magnesium chloride is also an option. However, the most creative road de-icer has gotta be the cheese brine used in some parts of Wisconsin: https://www.npr.org/sections/t... [npr.org]

        An added benefit is that while a salt solution freezes at -6C, cheese brine doesn't freeze until -21C.

    • Road salt absolutely has place in making streets safer. When there are puddles on the road at -15C you know they are using waaay too much of it.

      No, that's about right. When you can't tell if there is snow on the road or salt, that's too much!

      • No, that's about right. When you can't tell if there is snow on the road or salt, that's too much!

        "It's funny because it is true" - H Simpson.

    • You can use sand instead. Much of Europe uses sand, and it can be collected later and reused.

      • Plenty of places in the US also use sand. The western states typically use sand over salt primarily, and when they do use "salt" they favor substances like magnesium chloride, which are (supposedly) less harmful.
      • Mostly it is about money. We use salt because within its reasonable working temperature (down to about -8C or so) melting the snow off is much cheaper and faster than plowing it off.

        • Re: (Score:2)

          by PPH ( 736903 )

          melting the snow off

          It doesn't melt the snow off. It just melts it and forms big puddles of slush which need to be plowed off. Meanwhile, driving in slush is just as bad as on ice.

          • It doesn't melt the snow off. It just melts it and forms big puddles of slush which need to be plowed off.

            If you are doing that you are using even more way too much.

    • Does it? What if we used something more eco-friendly instead?

      https://www.mprnews.org/story/... [mprnews.org]

    • Salt may be useful when its around freezing point (0c) but not so much when its -30c like it was this morning (thats air temp, wind chill was -40 or colder)

    • Re: (Score:2)

      by Z00L00K ( 682162 )

      And salt also creates a lot of mud that ends up on windscreens causing lower visibility and a huge amount of washer fluid used too - which in turn also is an environmental impact medium.

    • Re: (Score:2)

      by q_e_t ( 5104099 )
      It'd be about 20% salt by mass to be liquid at -15!

      • It'd be about 20% salt by mass to be liquid at -15!

        Yes, that is indeed what happens when you spread salt on just a little bit of snow.

        • Re: (Score:2)

          by q_e_t ( 5104099 )
          I was under the impression that in Canada in winter it was more snow than just about anything else. That would require a LOT of salt :).

  • Who uses salt? Here in NJ they use calcium chloride, precisely because it doesn't cause the damage salt does. And it's just as effective.

    • Re: (Score:3, Insightful)

      by FuegoFuerte ( 247200 )

      Calcium chloride is a salt. Salt does not always mean table salt (NaCl).

      • But its concrete safe compared to rock salt.

      • Calcium chloride is a salt. Salt does not always mean table salt (NaCl).

        Got it. Obviously forgot high school chemistry!

    • Re: (Score:2)

      by tragedy ( 27079 )

      Who uses salt? Here in NJ they use calcium chloride, precisely because it doesn't cause the damage salt does. And it's just as effective.

      Calcium Chloride is salt. It's not plain table salt (although there's probably some in most table salt) but it is most definitely salt.

    • Calcium chloride is more effective. It melts more ice and at lower temperatures.

    • Re: (Score:2)

      by kriston ( 7886 )

      It's also a salt. We used to ice skate on a local pond in the 1970s and 1980s but it hasn't frozen over in several decades. We think it's because of the use of road salt, no matter which kind it is.

    • Re: (Score:2)

      by Rhipf ( 525263 )

      It isn't the sodium or calcium that is the problem with road salting it is the chloride part of the salt that is them main problem to the environment.

  • Just imagine what would happen if the deadly poison chemical known as sodium chloride made its way into the ocean. All the fish will die. We must also act to immediately remove any salt from the ocean. Desalinate the sea immediately.

    • Re:Oh noes salt (Score:5, Insightful)

      by sugar and acid ( 88555 ) on Friday January 07, 2022 @05:12PM (#62153145)

      Just imagine what would happen if the deadly poison chemical known as sodium chloride made its way into the ocean. All the fish will die. We must also act to immediately remove any salt from the ocean. Desalinate the sea immediately.

      Really you're going with that ignorant statement? Salinity in what is supposed to be fresh water and in the soil is a serious pollution issue around the world since ancient times. In fact "salting the earth" became a symbolic act over a conquered enemy in ancient times to show you had conquered their territory and wanted to stop them from growing back, effectively a symbolic pollution poisoning based on the ancient understanding of the effect of salt on arable land.

    • I know you are joking, but it does change soil ph. Precisely why invaders salted fields.

      • And is what is happening in areas in the southwest and California where they have over exploited irrigation in areas that are desert.

    • Re: (Score:2)

      by Rhipf ( 525263 )

      Just look at the Dead Sea to see the effects of a lot of salt in the oceans/seas.
      Just a fraction of that amount of salt in a fresh water lake can upset the biology and cause devastating effects.

  • Virginia there they all just stop on the highways and wait for things to melt. So much better for the environment and also a lot cheaper than all those plows and salt and sand trucks.
  • I lived in Pittsburgh for a number of years lots of ice and snow in the winter and lots of hills. By the spring the plants would all be dead for several feet along the roadside. It also ate the bodies of the cars. Patching holes in fenders and doors was a major industry. Unfortunately, no one has come up with a better solution. Short of people staying home after ice storms, I am not sure what the solution would be, calcium chloride is too expensive for bulk use and sand and cinders are not really that
    • We've known this for decades. Minnesota has had campaigns to encourage people to use less salt on their driveways for years. City and state plows have looked to use mixtures that decrease the amount of salt needed too.

    • ...sand and cinders are not really that effective.

      That's an understatement. Parts of Indiana use sand. All it does is make the ice brown.

      • Re: (Score:2)

        by DarkOx ( 621550 )

        Sand is very effective if the temperatures are cold and stay cold. It provides the grit you need for traction on solid ice. Where it does not work is places like Indiana and Pennsylvania and anywhere south where it warms up enough you are dealing with slush or where heat from the vehicles will be enough to make the top layers slushy.

        It works fine in places like North Dakota and Northern Minnesota.

    • Remember that guy working on solar powered roadways? One feature it offered was defrosting the roads. Of course if cars could hover that would solve issues too. You should get to work on that anti-grav hover plate.
    • No, it isn't news. Everyone that lives in the rust belt knows all about this and has for decades.

    • Re: (Score:2)

      by PPH ( 736903 )

      Unfortunately, no one has come up with a better solution.

      Tire chains.

      They improve traction. And they slow drivers down. Yeah, they damage the pavement. But that's surface damage, easily repaired. Not salt soaking down into bridge structures and rebar.

  • It could be worse (Score:5, Interesting)

    by taustin ( 171655 ) on Friday January 07, 2022 @05:09PM (#62153123) Homepage Journal

    The county I lived in in Missouri was too cheap to buy salt. Instead, when they trimmed the brush on the side of the highway, they would burn the debris and save the ash to put on the roads when it snowed.

    Know what you get when you mix ash with water? Caustic lye. It melted snow, but it also pretty well destroyed the wheel wells of cars.

  • If it comes down to me careening off of an icy bridge or making it safely across in sub-zero temperatures. I'll take the road salt, I'm more worried about the rust it causes on the bottom of my vehicles.

    Besides, it saves the county/state road maintenance departments from using those nasty herbicides along the side of the roads to keep the weeds down.

    I'm also sure that if this were 150 years ago the same eco-tards would be aghast as to where your toilet waste went on passenger trains.

    • Re:When it comes down to it (Score:5, Insightful)

      by Sique ( 173459 ) on Friday January 07, 2022 @05:34PM (#62153269) Homepage
      The same ecotards that managed to get canalization built to save cities from cholera and typhus epidemies. The same ecotards that managed the the lead out of the gas, the tap water controlled, the air cleaner and better to breath than ever since the begin of the industrialization. The same ecotards that are responsible for your flour not being stretched by gypsum, and your meat not moldy.

      Basically, the same ecotards that warrant your survival and your expected life span longer than 75 years.

    • I'll take the road salt, I'm more worried about the rust it causes on the bottom of my vehicles.

      You might want to try something like CRC marine heavy duty corrosion inhibitor. It’s a wax spray that does a good job protecting the underside of vehicles from corrosion. It adheres well, and won’t pressure wash off unless you’re using steam. It does not chip easily, self repairs somewhat, and can’t form pockets to trap moisture like rubber sprays. Been using it a few years on my vehicles and trailer and it has done a good job so far. If you drive on lots of gravel, you may have

    • Re: (Score:2)

      by kackle ( 910159 )

      I'm more worried about the rust it causes on the bottom of my vehicles.

      I had my used car undercoated when I first got it. It worked well, but I forgot to consider re-applying it years later. Sure enough, the road debris from the tires eventually "sandblasted" away the coating behind the tires over time, allowing rusting to commence.

  • Wait, let me put on my "shocked" face...

    8^O

  • Global warming to the rescue (Score:3)

    by SirLanse ( 625210 ) <<swwg69> <at> <yahoo.com>> on Friday January 07, 2022 @05:27PM (#62153247)
    With Global Warming, we won't need to use so much salt. One problem, solves another.
    • Yup. Remember, kids, the Very Smartest People said that snowfalls are just a thing of the past. [wattsupwiththat.com]

    • Except climate change weakens jet streams, and those jet streams used to keep the air over the North pole from wandering South much in the winter.

      So, sometimes it will actually be much, much colder in the US thanks to climate change.

      It's also why scientists started using climate change instead of global warming, because too many people got confused when "global warming" made things colder sometimes.

    • Where were headed, we won’t need roads.
  • We have known this for quite many years.
  • All that salt causes a ton of corrosion to the undercarriage of a vehicle. They should also consider the consequences the extra wear puts on vehicles and the more frequent repairs, replacements, etc and the environmental consequence that has in addition to just the direct effects of the salt on the environment.

    • All that salt causes a ton of corrosion to the undercarriage of a vehicle.

      They should also consider the consequences the extra wear puts on vehicles and the more frequent repairs, replacements, etc and the environmental consequence that has in addition to just the direct effects of the salt on the environment.

      Which is why we run our cars through a carwash once a week...

  • I cut my driving teeth in Ohio (Score:3)

    by RitchCraft ( 6454710 ) on Friday January 07, 2022 @05:48PM (#62153349)
    Got my license when I was 16 and drove two full winters in Ohio before leaving to serve in the USMC. Salt was always used in Ohio and worked well. In Memphis when it snowed (ever so slightly even) they all freaked out, shut everything down, and waited for it to melt. In North Carolina (eastern) they freaked out too but would put sand down. Sand worked well until the snow melted and only sand was left. Then it was like driving on little ball bearings, perhaps even worse than ice. Salts are the only thing I've seen that actually work well. Until a replacement for salts can be found, or we do like they did in Memphis and wait for it to melt, salts will continue to be used unfortunately. As a funny side note, the only cars on the roads in Memphis and NC were from Ohio, Michigan, and PA. We northerners had no fear of the snow, LOL. Steer into the slide.
  • Salt is fine when it's diluted by rainwater and washed into the rivers later in the year. So on the east coast, basically. But not a good fit for Oregon or Nevada where the salt will persist in soil basically forever.

    • Re: (Score:2)

      by caseih ( 160668 )

      Actually no it's not fine. It's not simply "washed" away presumably into the ocean. Over the years researchers have measured a marked increase in the salinity of rivers and streams in the US many months later. And lakes along the way get salted. It's a looming disaster, frankly. I read once that we're nearing a tipping point for many lakes. Obviously it's still a slow process, but given the rate of increase in the use of road salt, it's going to get worse faster.

  • Flagstaff, AZ has a better idea (Score:3)

    by Applehu Akbar ( 2968043 ) on Friday January 07, 2022 @07:07PM (#62153709)

    That city owns its own small volcano, which it quarries for cinder. Much easier on roads and cars, and there is no impact on the environment.

  • There's not a single thing we do that isn't in some way bad for the environment. Our very existence, safety and security depends on damage to the environment.

  • meh (Score:2)

    by ChoGGi ( 522069 )

    Salt is only good for car companies, grit is better for grip I find (lived in ON where they loved salting, and AB where they grit).

    A new windscreen is cheaper than a new car.

  • Suddenly this is an issue for the rest of the country because you just happened to get weather this week.

    "...little has been done to address the environmental impact of road salt..."
    Stop being stupid.
    https://experts.umn.edu/en/pro... [umn.edu]
    No, those of us in climates where this is a regular thing - MN, WI, Canada, etc - have for a long time been working with other substances instead of sodium chloride, because we're WELL AWARE of the damage salt causes to ecosystems and infrastructure.
    For example:
    Potassium Chlorid

  • Is there anyone in the Known Universe who doesn't already know this?

  • Also, it's bad for your car. Sand is basically just as good. In addition, there are more expensive substances that can be applied that work as well as salt, which usually isn't NaCl, iirc.

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