(First published December 2007, updated January 2011)
Ice building up on roads and footpaths isn't much of a problem throughout most
of Australia, so I was fascinated to learn of the environmental issues facing
other countries where major de-icing operations are an annual event.
The most common de-icing compound is sodium chloride - salt. When applied, it
melts any snow or ice on roads and sidewalks and helps prevent new ice from
forming. Sodium chloride is a very effective de-icing agent, is very easy to
obtain and is inexpensive.
The problem is that up to 90% of the salt enters the soil near the road as
runoff or splash and may even wind up a great distance away in waterways.
The widespread use of salt has created a number of environmental and other
problems, including:
- damage to roadside and garden vegetation.
- poisoning of pets
- contamination of well water
- increased salinity of waterways
- corrosion of vehicles and infrastructure
- Salt can plays havoc with soil nitrate and ammonium levels. Over a period
of time, the salt ladened soil can nitrify ammonium at a faster rate, and
these nitrates then wind up in local waterways. Very low levels of nitrates
increase the risk of eutrophication of rivers and lakes, plus cause algae blooms
in coastal waters.
Green de-icing tips
There's no doubt that icy roads are a killer; so something certainly needs to
be done and some governments are looking into various other substances that can
be used.
Calcium Magnesium Acetate (CMA) and Potassium acetate (KA) are both
biodegradable materials that have less of an environmental impact than rock
salt. Unfortunately, both CMA and KA are more expensive and ideally need
to be applied directly to surfaces before snow and ice is able to build up.
Since first writing this article, I've noticed other products are now on the
market that contain Magnesium Chloride and Sodium Acetate; both also touted to
be gentler on the environment.
Another option being researched is the use of beet juice mixed with brine.
Once sugar has been extracted from sugar beets, a waste product remains that
producers noticed never froze. This mix has been in use in several states,
including Illinois.
For around your own home, here's some other de-icing substances I found many
mentions of around the web said to have less of a negative effect on the
environment when compared to rock salt.
- Spreading urea instead of rock salt. Urea is still a salt, but with less
impact. Note : rock salt will melt ice down to -15°C (5°F), while urea will
only melt ice down to -4°C (25°F).
- Calcium chloride (pretty much as above)
- Wood
ash
- Sand
- Sprinkle baking soda lightly over steps
- Volcanic rock
- Spent grains from brewery
- Mix a tablespoon of rubbing alcohol, a quart of water, and a drop
dishwashing liquid. Increase alcohol levels for a more rapid effect.
Used
coffee grounds can also be used, not so much to melt the ice, but to provide
traction and help prevent slipping.
Prevention being better than cure, shovelling snow from paths as soon as it's
fallen can also greatly decrease ice build-up; so if you're up to a bit of
physical effort, it's another way you can exercise
for the environment.
Regardless of what you using for de-icing, bear in mind that more is not
necessarily better (except in the case of shovelling I guess), so always follow
the manufacturers guidelines for any product you use in order to minimize
environmental damage.
For keeping your car's windscreen free of ice, fill your windshield wiper
tank with a mix of one part water and two parts vinegar and use the mix prior to
leaving your vehicle for the night - this should help prevent ice build up.
Have some de-icing tips? Please share them below!
