You may ask yourself, "What's wrong with using
road salt?" Just go to an automotive body shop and ask how much they charge to
repair rust damage to your vehicle. According to federal estimates, road salt causes
$3.5-$7.0 billion in corrosion damage each year. Also consider that the chloride
levels in lakes near major highways is seven times the normal level. This excess
chloride can allow heavy metals to enter the water from the soil and poison living things.
So why do we use road salt? Simple. It's cheap (about $30
per ton) and it works! One alternative is a substance called calcium magnesium
acetate (CMA). But at $700 per ton, it seems that its less corrosive nature comes
with a large price tag. Airports already use CMA to prevent damage to the aircrafts.
However, if CMA could be produced at a much lower cost, its usefulness may be
affordable. That's the motivation for a group of researchers at Michigan Tech's
Institute for Materials Processing. The research group recognizes that agricultural
waste can be broken down by microbes producing an abundance of acetic acid (the acid found
naturally in vinegar). The other components (calcium and magnesium) can be supplied
by waste dust from limestone quarries. The researchers also suggest adding crushed
glass to improve traction.
Preliminary results suggest that the mixture will work well and last
longer. Of course, the news is not all good. While not as damaging as road
salt, CMA isn't exactly good for the environment as it reduces water's ability to hold
dissolved oxygen. The could result is suffocated marine life if the oxygen level
drops low enough. CMA will not gain acceptance until its production costs are
comparable to salt, but we've got to start somewhere, and isn't your car's paint job worth
the effort?
