After the world war two, many countries suffered from food
shortage and this facilitated the intoruction of fertilizers and other
Natural land pollution:
Land pollution occurs massively during earth quakes, land slides,
hurricanes and floods. All cause hard to clean mess, which is expensive
to clean , and may sometimes take years to restore the affected area. These
kinds of natural disasters are not only a problem in that they cause pollution
but also because they leave many victims homeless.
Soil pollution is defined as the build-up in soils of persistent
toxic compounds, chemicals, salts, radioactive materials, or disease causing
agents, which have adverse effects on plant growth and animal health.
The wars that hit the earth are probably the immediate cause of soil
pollution. Not talking in the sense of how many people died but in that
it is through this period that many countries found the necessity to improve
their living standards. After the world war two, many countries suffered
from food shortage and this facilitated the intoruction of fertilizers
and other agricultural chemicals. Although KNP [ Potassium, Nitrogen, Phosphorus]
fertilisers has not led to soil pollution, the application of trace elements
Pesticides such as DDT [dichlorodiphenyltrichloroethane]a
colourless chemical pesticide, which is a potent nerve poison in insects
was first widely used to combat diseases such as yellow fever and malaria.
It was later used to control and/ or eradicate disease carrying and crop
eating insects. DDT was later on discovered to cause endagerement of species
in the same food chain as the
controlled insects, particularly birds. DDT prevents the shelling of
bird eggs and in humans causes health threats.
In yet another famous war of Vietnam in 1970's was introduced another
Chemical substance which had a more adverse effect than that of DDT, Dioxin
a chemical impurity resulting from the production of the auxin 2,4,5T.
Dioxin is a toxic chemical and was used as a defoliant by the American
army. Dioxin was a major constituent of argent orange which was applied
on trees which would then fall off reaviling enemy camps. After the war
it was found that the chemical cause congenital deformalities and mental
effects to the children born to the American soldiers and in the
area over which it was applied. In minute amount dioxin has the ability
to cause cancer,chloracne, miscarriage, and fetal abnormalities.
Glass industries have also been responsible of soil pollution. The
glass industries uses Arsenic to eliminate a green colour caused
by impurities of iron compounds. because arsenic is a violent poison, yet
it is widely used and therefore is a frequent contaminant. James Marsh,
supplies a simple method for detecting traces of arsenic so minute that
they would escape discovery in ordinary analysis. Arsenic is sometimes
added to lead to harden it and is also used in the manufacture of such
military poison gases as lewisite and adamsite. Until the introduction
of penicillin, arsenic was of great importance in the treatment of syphilis.
In other medicinal uses, it has been displaced by sulpha drugs or antibiotics.
Lead arsenate, calcium arsenate, and Paris green are used extensively as
insecticides. Pollution of land by heavy metals is a result of the mining
of ores to extract metals such as tin, silver, nickel, lead, iron, chromium
and copper. Most of these metals occur naturally as ions in the soils.
Though some metals, such as copper, iron, and zinc , are necessary for
plant growth. It is the high concentration if these ions that renders the
land unsuitable for plant growth. Soil pollution is widely linked to chemical
substances but irrigation. is somehow linked
to it as well.
Soil pollution has been slightly controlled by putting regulations
on the use of DDT and introduction of alternatives to it. However the task
of eliminating completely soil pollution is not easy, third some third
world countries still utilize pollutants such as DDT as pesticides. Mining
cannot be stopped because we are in constant need for mineral ores for