Salt contamination is when an area of land becomes
over salinized, causing a negative impact on soil fertility. In order to get
their required hydration, plants use the process of osmosis where ground water
is taken in from the typically lower salt concentrated soil to the higher salt
concentrated plant cells. When this balance is thrown off it can have bad consequences
like water uptake being drastically slowed down, and plants becoming so
concentrated with toxic levels of salt that they show signs of dying like dry patchy
leaves and defoliation. This is a phenomenon that can either occur naturally or
through human activity, known as primary or secondary salinity respectively. Primary
salinity happens through means like salt marshes, salt lakes, and through
natural disasters like tsunamis that suddenly introduce heavy amounts of salt
water into the ecosystem. Of greater concern is secondary salinity which can be
caused by poor irrigation practices and through using mass amounts of salt as a
means of deicing roads in cold climates.
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| Visual identifiers of salt contamination include the formation white patches and land cracking. |
Salt contamination is commonly present in in
places that are suffering from low rainfall and irrigation must be used to
supply crops with the necessary amount of water. Poor drainage of irrigated
land, use of water that is already heavy in salt, and over irrigating that causes
roots to be waterlogged and inhibits their ability to exclude sodium intake are
all farming practices that can lead to salt contamination.
Dousing roads with heavy amounts of salt in cold
climate areas is an effective way of keeping them free of ice and snow because
the salt lowers the freezing point of the water, thus making driving conditions
much safer. The EPA estimates that 15 million tons of sodium chloride are used
on U.S. roads every year and suggests using alternatives methods when possible.
Calcium chloride, magnesium chloride, and potassium chloride are all effective
at even lower temperatures but their higher price point makes them a less
desirable option. Once the soil along
roads and freeways becomes contaminated, plants become overly saturated and
lose their ability to take in water and other nutrients and the balance of the
soil can be thrown off to a degree that can lead to erosion, posing a threat of
pollution in nearby bodies of water. Preventive measures to these problems
range from properly maintaining salt piles on the sides of roads to the use of
acetate based deicers, although these deicers are more expensive and don’t tend
to work in temperatures lower than 23 degrees Fahrenheit.
It is easy to pass off salt as a commonly occurring
substance that can’t cause harm to our planet and its ecosystems but it is definitely
a cause for concern. Preventive measures may be more expensive from a money
point of view but, in the long run, not implementing them could prove more
costly in other ways.
Added by Will Baker
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