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Calcium-Based Ice Melt is Safer for Lawns

This lawn was by a walkway was ravaged by excess applications of rock salt in winter.

This lawn was by a walkway was ravaged by excess applications of rock salt in winter.

STEPPING OUTSIDE IN MAINE today the walkway and driveway were literally glare ice, to the point where it would have been safer to lace up the skates than to walk in boots to the car. I’m personally stubborn with winter; I do keep the pathways clear, but I’m not big on salt, sand, grit or other coatings to keep things safe. I figure spring will be here soon enough and I hate the indoor cleanup required from tracking all that stuff inside the house.

My wife tells me my attitude is flippant, that I only get to feel that way because I travel so much that it makes winter feel shorter to me. She’s fairly insistent about the bag of ice-melt by the front door. I know from the questions we get about which products to use that some of you are, too.

So with the goal of keeping the lawn and other plants as healthy as possible, here’s a rundown on what you can use to maintain optimum traction — and landscape health:

ROCK SALT — This is among the cheapest of the products that actually melt the ice, but it’s also among the most harsh things you can apply to the lawn and garden. When the sodium chloride dissolves, the sodium can burn the grass (see photo, above) and the feeder roots of trees, shrubs and perennials. The landscape can probably survive one or two applications of rock salt throughout the winter, but you should try to avoid any more than that. Don’t even bother to use it if temperatures are much below 20 degrees Fahrenheit. The salt will just sit there and not melt a thing.

CALCIUM CHLORIDE — This basically functions just like sodium chloride by melting the ice, but with the primary component being calcium the plants actually can benefit from a few applications. This is usually more expensive, depending on the source, but it’s worth it for your landscape and even your pets — which can get sick from licking too much salt. This product works at the lowest temperature range of any melter, down to 25 below zero.

CALCIUM MAGNESIUM ACETATE — This alternative calcium derivative combines dolomitic limestone and acetic acid in an environmentally friendly formula that apparently has no corrosive properties at all. It’s pricier than rock salt — about $20 for a 50-pound bag at my local hardware store. But my plants near the walkways are worth a lot, too, so this is what we usually keep by the door when I don’t use some of the free stuff, below. If the temperatures are below -5 to -10, this product doesn’t seem to work all that well.

MAGNESIUM CHLORIDE HEXAHYDRATE — This is the stuff many airports use on the tarmac and many state highway departments are beginning to bring in. It’s also the active ingredient in many so-called pet-safe products.

LAWN FERTILIZER — In a pinch when it’s not too cold, you can use your lawn and garden fertilizer as a de-icer and traction aid — especially if the product contains relatively high levels of nitrogen. As the product dissovles, the nitrogen will melt the ice. Don’t use this more than once or twice a winter, though, because too much nitrogen will burn the lawn, too.

SAND, GRANITE DUST OR WOOD ASH — When I just want to increase traction, I spread the free stuff. All of this tracks into the house and creates its own cleanup nightmares, but if people are coming by for a visit, the cleanup is far better than having someone fall.

About The Author

Paul Tukey

An international leader of the green movement, Mr. Tukey is a journalist, author, filmmaker, TV host, activist and award-winning public speaker, who is widely recognized as North America's leading advocate for landscape sustainability and toxic pesticide reduction strategies.

Number of Entries : 1024
  • Daniel Hawley

    I thought that you might be interested in these articles about magnesium chloride. Aspen, Colorado has banned the use of this product.

    Dan

    http://www.psa-rising.com/upfront/sgreenwoodcad82003.html

    Cadmium, contained in street de-icer magnesium chloride, linked to human cancer

    Aspen, Colorado.

    Cadmium, contained in the street de-icer magnesium chloride, is a human carcinogen, according to the Tenth Annual Report of the U.S. Department of Health and Human Services. There is no safe level of cadmium — a soft, silver-white metal — upgraded from “Reasonably Anticipated to be a Human Carcinogen” to “Known to be a Human Carcinogen.”

    Cadmium has been linked to both breast cancer and prostate cancer. It has pulmonary toxicity and causes lung cancer. Cadmium is the principal killer in cigarette smoke.

    According to a summary chapter from the Toxicological Profile for Cadmium released by the Agency for Toxic Substances and Disease Registry (ATSDR), “Most of the cadmium that enters your body goes to your kidney and liver and can remain there for many years.” The report goes on to say that cadmium can enter your body from the food you eat, the water you drink, from particles attached to the air or from breathing cigarette smoke.

    An Aspen Times series on mag chloride said Aspen air has elevated levels of both cadmium and arsenic. Dr. Stephen Strum, founder of the Prostate Cancer Research Institute (PCRI) in Marina del Rey, Ca., told the Aspen Free Press: “Cadmium is definitely associated with prostate cancer risk.” When told that Aspen had used the street de-icer magnesium chloride containing both cadmium and arsenic, he said, “This is certainly cause for alarm.”

    In 1982 a medical study showed that cadmium levels found in tissue of removed prostate tumors were eight times greater than cadmium levels in normal prostate tissue. Another study found a 25-fold increase in cadmium levels of prostate tumors.

    A 1997 medical study has found an increased risk for lung cancer in cadmium-exposed workers, but says: “the association was significant only with the cadmium-exposed workers who had also been exposed to arsenic,” also contained in the street de-icer magnesium chloride.

    According to a report by the Occupational Safety and Health Administration (OSHA), “Because of the body’s ability to accumulate and store cadmium over long periods of time, the loss of kidney function may develop even after a reduction or cessation of external cadmium exposure.”

    OSHA goes on to say, “exposure to cadmium causes cancer, kidney dysfunction, reduced pulmonary function, and chronic lung disease indicative of emphysema.” Of course these conditions don’t occur overnight and most people can’t tell by smell or taste that cadmium is present in air or water … water which flows into rivers and streams from roads coated in cadmium-laced magnesium chloride to keep ice melted.

    Federal guidelines continue to call for less and less cadmium exposure in the workplace, according to OSHA, “because a number of studies of workers suggest an association between occupational cadmium exposures and increased deaths from cancer, most notably prostate cancer.”

    When I was diagnosed with prostate cancer, the first question a physician asked me was, “Have you been around cadmium?” I didn’t know it then but I had been wading through cadmium in mag chloride applied to the streets of Aspen for several winters. Aspen City Council has an on-again-off-again history with mag chloride. The last winter that I recall the de-icer on local streets to any extent was, for a time, during the winter of 2001.

    The Agency for Toxic Substances and Disease Registry says, “There are no good effects from taking in cadmium. Breathing air with high levels of cadmium can severely damage the lungs and may cause death. Breathing air with low levels of cadmium for long periods of time (for years) results in a buildup of cadmium in the kidney and may result in kidney disease.” Other effects that could occur after breathing cadmium for a long time, besides cancer, are lung damage and fragile bones.

    Cancer statistics indicate that the prostate cancer rate in Aspen has been climbing. It seems like a lot of men here, in their late forties and early fifties (young for prostate cancer), are getting it. It’s difficult to pinpoint the cause when one gets cancer. Usually it’s a multiplicity of factors, including genetic predisposition, age, exposure to environmental carcinogens and general health. And, according to studies, it’s not that cadmium necessarily creates prostate cancer from scratch. Most men, as they age, develop prostate tumors, but they are held in check by tumor suppressor genes and remain latent, i.e. harmless.

    If these tumor suppressor genes somehow get mutated, a harmless prostate tumor becomes “clinical,” i.e. needing cancer therapy. One tumor suppressor gene is the p-53. Clinical tests indicate that cadmium — contained in the street de-icer magnesium chloride — even at non-toxic levels, “impairs p-53 function,” not only for prostate cancer but also for lung cancer and some lines of breast cancer.

    Sterling Greenwood, publisher-editor of the Aspen Free Press, has been battling prostate cancer for seven years. He and other residents of Aspen, Colorado campaigned successfully to end use of magnesium chloride on the roads. Visit the Aspen Free Press online at http://www.aspenfreepress.com

    How Magnesium Chloride Damages Concrete:

    One must have a fundamental knowledge of concrete in its hardened state. Concrete, when setting from a plastic to hardened condition, goes through a number of chemical reactions. Basically, hardened concrete consists of two major chemical compounds; calcium-silicate-hydrate and calcium hydroxide. Actually, the reaction products from cement hydration with water are very chemically complex, but for the purposes of this review, we will stick to the basics. When concrete is to be exposed to severe freezing, it is standard practice to entrain a system of microscopic air bubbles in concrete mixtures typically occupying a volume of 5-8%. The purpose of this air-void system is to provide space for the increased volume that water will occupy as it becomes ice. If one were to look at concrete under a microscope in the range of 3000X, this entrained air would look very much like a wasp nest.

    Magnesium chloride for deicing is effective in reducing the temperature at which water freezes. The problem begins as the magnesium chloride comes into contact with the now deiced concrete surface and remains contained in the melt water, and permeates into the concrete. While deicing salts containing sodium, potassium and calcium are chemically innocuous to concrete, this is not true of magnesium. The magnesium ions accumulate and react with the cementitious compound calcium- silicate-hydrate converting it to magnesium-silicate-hydrate (or a mineral called brucite), which is non-cementitious in nature. In other words, a fundamental major mineralogical product of solidified concrete has now been chemically altered (completely changed). Formation of magnesium-silicate- hydrate breaks down the “glue” that binds aggregates together and concrete surfaces begin to deteriorate. The net effect is we now have a chemical and physical attack that concrete is not designed to withstand, nor be subjected to.

    Now that a fundamental understanding of what happens to concrete when magnesium chloride is used as a deicing material has been provided, it becomes a matter of a public decision. On the positive side, magnesium chloride does contribute to ease, convenience, and most importantly the safety of the motoring public. The bad news is that the consequent damage to concrete and its financial impact upon the community at large is significant. Private property owners particularly suffer damage and are looking for someone to blame. A couple of essential points: The magnesium chloride adheres to vehicle tires and to the vehicle itself and is therefore contaminating private property owners’ driveways and sidewalks and causing damage as previously outlined.

    Who is to pay for this? It is not realistic to expect building contractors and the ready mixed concrete industry to bear the financial burden of a problem caused by a governmental decision. If the government was willing to repair the private property damage then it is certainly fine with the concrete industry if they want to damage their own roads. Of course, one must remember that the roads will have a much-reduced life cycle unless options for concrete mixtures are employed to resist the effects of magnesium chloride. It should be very clear at this point that private industry has no intention of paying for any damage that occurs as a result of the use of inappropriate chemical substances.

    The last essential point of this review is that this material is extremely corrosive, causing damage to plant and vegetable life, and greatly accelerating the destruction of most metals, primarily automobiles and their accessories. The producers of the magnesium chloride claim to have integrated a corrosion inhibitor to attempt to negate some of the auto damage, but a joint study by the Colorado Transportation Department and a National Trucking Association (as a result of truckers complaints about corrosion to their vehicles and electronics) has not borne out that this “ corrosion inhibitor “ is effective.

  • Scott Morgan

    Would these recommendations hold if you have excessive calcium in your soil?

  • http://www.natraturf.com Craig Dick

    Any product with Chloride in it will leach calcium form the soil, you could also use potassium chloride, available at many garden centers. Calcium Chloride is highly water soluble and will leach. In high calcium soils you can use potassium chloride which will leach calcium and leave potassium behind.

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