If you live in a place where there are both cars and snow, you can experience the annual salinity of the streets up close. Since at least the 1940s, Americans have been salting in the snowy states every year, often several times a year, to make our roads safer. Ask anyone who is freaked out or accidentally comes across a piece of black ice: slippery roads are not something to make fun of, and salt can be a necessary, even life-saving tactic for winter road warriors.
The problem is that the salting of the earth is a biblical notion: it is what you did to an enemy to make land unproductive for agriculture.
In the 20th century, salt changed from an old war tactic to an economically necessary step that got the country’s industrial engine going. Salt’s new role was to keep US roads open at all costs. The economy depended on it.
But now these biblical results are obvious: environmental damage must be expected. However, we simply cannot afford to be salt-free.
Nowadays, closing a state’s roads due to winter weather can cost hundreds of millions of dollars, says Michael Smith, a technical training specialist at Bay State Roads at the University of Massachusetts Transportation Center. For example, shutting down the streets of Massachusetts (as happened throughout Massachusetts in 2013 or 2013) can cost between $ 300 and $ 700 million a day, says Smith.
And so we drop as a nation 22 million tons Salt on our streets every year.
Fish, animals, insects, plants and algae have changed their behavior in response to the current levels of road salt that enter their habitats. Some types of frog change sex due to these massive doses of salt. High doses can kill them and other wildlife. For nature lovers, people who like fishing or enjoy nature in some other way, and for locals who rely on natural tourism, the side effects of salt cannot be overlooked.
A hybrid beet juice-salt water-salt solution is helpful to coat the asphalt before a blizzard so that no precipitation remains on the roads. (AP Photo / Gene J. Puskar)
The salt drain also penetrates our house drinking water supply, It Corrodes our pipesThis leads to a higher content of lead, manganese and mercury (including heavy metals, all of which are toxic to humans) in our drinking and bathing water. Experts agree that exposure to such high salt levels can even be problematic for people who have a low sodium diet.
Perhaps more relevant to the paperback is the effect of salt on our vehicles: this rust on your car? Salt. The road deterioration that damaged your car? Salt. Or maybe more specifically magnesium chloride, Indeed tThe generic term “road salt” refers to one of three chlorides: sodium chloride (rock salt), magnesium chloride and calcium chloride.
Dr. Rick Relyea is director of the Darrin Fresh Water Institute and the Jefferson project at the Rensselaer Polytechnic Institute in Troy, New York, which has been studying the effects of road salt since 2014.
Relyea emphasizes: “It is undeniably important for safety to remove ice.” But at what price?
“In general, what we now know as road salt can be deadly to a variety of plants and animals, and as always, it depends on the dose,” says Relyea. “So if we have a lot of road salt, we can kill all kinds of plants and animals. It is different in different parts of the world. “
Over the past five years, as public awareness of the problems with these chlorides has grown, communities across the country have responded with changes that will hopefully be cost effective, good for the environment, and good for public safety.
In Lake George, New York, environmental research has found surprising and significant damage to nature and has stimulated a change in the way roads are salted. In Cambridge, drinking water is so rich in salt that coffee machines corrode, and the city tries to alleviate the problem both within its own city limits and in neighboring cities that affect its watershed. In Helena, Montana, concern about the environmental impact of salt – and cars – inspired a program that takes recycling to a new level.
In Lake George Village, Brining to save the wildlife
In Lake George Village, New York, Relyea says, they use saline that they apply to the road before a blizzard, making it more difficult for the snow to stick to asphalt and be easier to remove with the plow.
Brining sounds like something you do with meat before a holiday dinner, and it’s a similar principle used here. For example, brine consists of 80 percent water and 20 percent salt, and this is then placed on the sidewalk before a flake ever falls. The salt solution prevents the snow from sticking, which makes plowing easier and prevents the formation of black ice. Many municipalities have their own “brine recipe” that can be adapted to local conditions. This recipe often calls for “a little carbohydrate,” as more than one expert told us.
Carbohydrates – essentially sugar – lower the freezing point. Beet juice is used in some places, while others experiment with molasses, corn and soybean oil. It is the sugar that makes the brine sticky and effective at low temperatures. Imagine the same principle as a Coca-Cola or a bottle of vodka in the freezer. neither freezes completely. This way, the brine recipe is really a recipe.
If you dilute the road with salt first, the snow will not stick and the road can quickly become dry asphalt. If you pour rock salt on snow that has already fallen, more salt needs to be used, and then the snow melts from the top down, waiting for the vehicle tires to crush the salt and mix with the snow melt to turn into brine anyway. Only process the snow when it is liquid or in brine. Applying pure salt after the snowfall takes more time and salt and can result in lower layers of snow sticking to the sidewalk as they melt from the top down and not from the bottom (as with the saline solution).
The Jefferson project uses a network of radio frequency sensors, including this vertical profiler, to obtain real-time data on the movement of water and pollutants through the Lake George watershed. (Photo courtesy of Jefferson Project)
According to Relyea, Lake George has also changed the edges of their plows. A normal plow, probably 10 to 12 feet wide, usually leaves snow on these paved roads. The plow cannot follow the natural curves of the road. So the community started with a “living edge” of 5 smaller plows mounted on springs so that they would conform to the road contour and remove more snow.
These two relatively small changes have reduced salt consumption in Lake George by 30 percent in recent years, which is a major improvement, according to Relyea.
The vast majority of the salt lake George uses is sodium chloride. But is it really safer than calcium or magnesium chloride, for example? “Not really,” says Relyea. “Depending on the type [of plant, algae, fish, reptile or animal you’re talking about], something [chlorides] are much more lethal to plants and animals than others, and it’s not always the same. ”
Take the rainbow trout. Calcium chloride is worse for fish than sodium chloride, he says. Magnesium chloride is also bad for fish. “Which plant or animal? [you talk about] depends on what [road chemical] is worse.”
“The effects are fairly simple in some cases,” says Relyea. “Salt does things with animals that nobody knows about.” For example, if tadpoles of forest frogs are exposed to high salt concentrations, their gender can change, “Nobody had this expectation,” says Relyea.
“What is it really about? [are the] especially salt-sensitive groups of animals, ”adds Relyea. “Zooplankton eat algae. They are the reason why a lake is clear. We saw in Canada where it only takes 50 milligrams [of salt] to kill them. “Larger fish eat the zooplankton and larger fish eat them and so on. In an ecosystem built on zooplankton, food starvation is a problem.
“We have to worry about that,” says Relyea. “There is a certain amount of hope. And that means that some animals can quickly develop a higher salt tolerance within a few months. You are more tolerant than three months ago. You can still kill them, ”adds Relyea. But “they’re a bit harder. It suggests that others might have this ability. This ability to develop could save us time [with some species]But some things will not develop and die. ”
And then there are the unintended compromises when species develop tolerances to road salt. Plankton, says Relyea, “develop, but no longer have a circadian clock, ”This watch used to dictate things like surfacing and going deep to avoid predators. The loss of the circadian clock makes it a sedentary duck for predators. “It’s an enormous impact,” says Relyea. Again he notes: “Not at all what we expected.”
Another alarming consequence that Relyea cites is the increasing salinization of the Great Lakes, where invasive, saltwater-friendly species like zebra mussels are now doing well. As the Great Lakes get saltier, invasive species are likely to do even better.
Back at Lake George, the spring snow brings a mega dose of salt. According to Relyea, during a spring rain or melt, the salinity in streams can increase to 2,000 milligrams of chloride per liter of water, instead of 230 milligrams of chloride per liter of water, as required by the EPA guidelines. (He notes that the Canadians have lowered the bar even further, at 140 milligrams per liter.) Relyea says they don’t yet know what such short-term, massive peaks will do. The short-term guideline set by the EPA is 860 milligrams per liter, he notes. “We expect it to do a lot of damage.”
Lake George is a major driver of the $ 2 billion tourism industry in the Adirondack region. It is therefore important to protect the natural environment. Clear streets and a healthy ecosystem are crucial for seasonal tourism. “Feeding the entire watershed with little salt,” says Relyea, is a win.
Desalination of Cambridge water supply for drinking and making coffee
Cambridge, Massachusetts, home of Harvard and MIT, has its own water source that is separate from many systems in the Boston area. However, in addition to the 225,000 to 250,000 cars that run on Route 128 every day, the city’s drinking water reservoirs are affected by high-speed, multi-lane traffic. Under these conditions and during a snow storm, road salt crews are in great demand and can get stuck in traffic, which makes deicing difficult. The need to protect busy roads for travel makes the watershed more prone to high salinity. A look at the Cambridge water quality report over several years shows that the sodium content from the drainage of road salt is significant water pollution,
For coffee connoisseurs in Cambridge, the chlorides in the water cause trouble for the machines that brew their high-quality coffee. Even machines that are under warranty are not covered if they are exposed to salt water. “Chloride becomes acidic and caustic under heat and pressure. This means that the device will not last as long as it should, ”reports a local NPR branch WGBH,
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