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Rock Salt and The Environment
According to recently conducted national surveys, approximately 60% of American households reportedly use rock salt and other salt-based products to melt snow and ice during the winter season.
It is actually quite alarming that a lot of people are completely unaware of the health and environmental dangers associated with this product. Rock salt, along with other salt-based products used as ice melters, contain potassium chloride or sodium chloride, which can easily heat up to 175 degrees when it is exposed to ice, water and low temperatures. Before they penetrate snow and ice, these white pellets sit on the surface for extended periods of time, which poses a danger to pets, the environment and your property.
Understanding the Freeze and Thaw Cycle
We were taught back in 6th grade that when the temperature reaches 32 degrees Fahrenheit or 0 degree Celsius, water will freeze and transform into ice. Obviously, in much of the US temperatures tend to routinely drop below 32 degrees Fahrenheit during the winter season, which results in snow, freezing rain and ice.
Rock salt is used because it has the ability to lower water’s freezing point, allowing it to withstand low temperatures without solidifying into ice, but only at around 15-20 degrees Fahrenheit. However, if the surface is colder or falls to sub-zero temperatures, rock salt will have no effect.
When you use rock salt on snow and ice to clear masonry or concrete walkways, it will slowly dissolve into the water and spread outward, spreading out to a larger area. So as temperatures rise and fall, the water freezes and thaws, creating what is known as the freeze and thaw cycle. When rock salt is applied to ice which eventually becomes water, it seeps into the surface pores and cracks of the concrete or masonry surface.
The problem is that rock salt, along with other ice melting products, increases the freeze and thaw cycle and at the same time doubles the rate of expansion during the freezing process. So when the freezing process begins again, it expands, placing significant stress on the surface. Over time this will cause the concrete to pit and crack because of the added stress.
The Downside of Using Rock Salt
While rock salt is widely used to melt ice and snow, it certainly carries a number of serious drawbacks:
- Temperature: As discussed above, salt is only effective down to temperatures of between 15 and 20 degrees Fahrenheit, which means, it will not work in extremely cold conditions.
- Contamination: With salt added to snow and ice, it can seep into the ground water, leading to contamination of water, especially when not managed properly.
- Oxidization: It is common knowledge that salt causes rusting and corrosion.
- Environmental issues: Using rock salt in large quantities can cause damage to vegetation and pose dangers to animals.
Damage to Concrete
Stone, masonry, and concrete that are less than a year old are known to be particularly vulnerable to the effects of the freeze and thaw cycle. So while concrete driveways and sidewalks may appear very solid, concrete is essentially a porous material that absorbs water. If rock salt or other chemical ice melters are applied, the water and salt mixture is absorbed by the concrete, once the ice or snow melts.
In addition, rock salt is known to be hydroscopic, which basically means that it has a tendency to attract more water. When it is mixed with water and penetrates concrete, about 10% more water is absorbed and causes a larger problem when the water re-freezes and expands.
Danger to Pets
Using rock salt also poses a serious danger to pets, especially for dogs. This is because salt can seep into the paws and the fur. During high temperatures, the salt can burn the skin surface, causing redness and skin ulcers, which may ultimately lead to bacterial infections. Exposure to excessive salt, often through licking salt off their paws, can also trigger intestinal problems and stomach inflammation.
For cats, licking salt can lead to gastrointestinal distress. Common symptoms include vomiting, salivating, quivering and diarrhea. In cases where copious amounts of salt was ingested, it lead to bodily weakness, excessive thirst and even seizures, with the worst case scenario being death. This is mainly due to the chemicals found in rock salt, which are very toxic and harmful to felines.
Detrimental to Plants and Vegetation
Plants can also be damaged when their foliage and roots are exposed to water with high salt content. The water and salt mixture, when it percolates through the soil profile can affect the plant roots, soil particles and soil microbes. In particular, it causes water stress, which can result in depressed yield and growth. It can affect the soil quality by displacing phosphorus and potassium, which results in the reduction of aeration, drainage and increases soil compaction and density.
Mineral nutrition is also affected with an excessive concentration of chloride and sodium in plant roots. This is because plants tend to absorb salt water instead of nutrients derived from phosphorus and potassium, which can lead to a deficiency.
Alternatives to Rock Salt
There are safer alternatives to handling ice and snow during the winter season. If you don’t relish the idea of shoveling snow, here are some alternatives you may want to consider:
- Electric-Powered Snow Blowers: If your area is particularly cold during the winter season, an electric-powered snow blower can present a smart alternative to rock salt and gas-powered blowers, which are known to generate more noise and air pollution.
- Snow Melt Mat: If you are planning to replace an old driveway or walkway, consider investing in a snow melt mat. The mat is basically composed of electric wires that heat the driveway or walkway from underneath, radiating heat upwards. While this may mean you have to pay for electricity, it certainly beats shoveling the heavy snow and the potential risks of using rock salt.
- Heated Mats: If your walkway is already installed you can consider using a heated mat. Heated mats lay on the surface of your walkway and melt snow as it lands on the surface so you don’t have to shovel or use rock salt at all.
- Potassium Chloride: Sold as small pellets, this product is known to work effectively at temperatures between 10 to 12 degrees Fahrenheit. It is also considered to be significantly less lethal to the environment. The main drawback is the price since potassium chloride typically costs twice the price of salt. Typically, you will need to use a larger amount of pellets to treat the same area.
- Calcium Chloride: For people living in extremely cold regions, calcium chloride is known to work in conditions as low as -24 degrees Fahrenheit. It is important to note that it should be used sparingly as it is much more potent than other options. Be prepared to spend twice as much as the price of rock salt.
- Potassium Acetate: Easily among the most expensive alternatives, this one costs as much as seven to eight times the price of rock salt. However, if you are on the lookout for something that will work down to -76 degrees Fahrenheit, this is the most effective option.
If you are looking for an environmentally-friendly alternative to rock salt, here are some products you can use during the winter months:
- Urea: This is a product that is typically used for the production of fertilizer, which also happens to be a great and effective alternative to rock salt to de-ice your property. Urea, which is produced from natural gas generally, has a relative performance to rock salt, although known to be less poisonous.
- Beet Juice: To date, this purple liquid has grown increasingly popular for applications involving larger areas.
- Sand: Another great alternative to rock salt is sand as it is effective in providing traction. Aside from the fact that it does not pose any detrimental effects on the environment, it is inexpensive and can be easily removed. Ideally, you will want to look into using brick sand as it is known to be more coarse and considerably more granular compared to usual sand. You can purchase brick sand from any regular building supply store.
- Ashes: If you have a fireplace at home, ashes also present a convenient and more economical alternative to rock salt. Ashes are also good at providing traction and helps melt ice quickly during sunny days as they tend to absorb sunlight.
- Kitty Litter: While this may be a more expensive alternative to other natural, eco-friendly options, it is known to provide a great deal of traction. If you happen to have kitty litter at home, then you can opt to use it instead of rock salt. However, the residual material tends to turn into a bit of a mess when the ice and snow melts.
As winter starts to roll in, safety should always be a primary concern. Snow and ice can make surfaces slippery and can potentially lead to accidents and injuries, something that you as a property owner will be accountable for. It is critical to maintain a safe, hazard-free environment around your property.
With this in mind, it is important that you exercise due diligence in choosing a product to use to melt ice and snow. During the winter season, removing ice and snow is critical, no matter how you plan to do it. Whatever product you plan to use, it is important that you apply it early and in moderation. Always make sure to take into consideration your safety and the people around you, including your pets, and of course, the impact of the product you plan to use on the environment.