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 has.
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.
CONTROL
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 different applications.
Industry shares of emissions of organic water pollutants refer to emissions from manufacturing activities as defined by two-digit divisions of the International Standard Industrial Classification (ISIC), revision 2: stone, ceramics, and glass (36). Emissions of organic water pollutants are measured by biochemical oxygen demand, which refers to the amount of oxygen that bacteria in water will consume in breaking down waste. This is a standard water-treatment test for the presence of organic pollutants.
