Pollution by substances used intentionally in agriculture

Pesticides and industrial fertilizers are the chief chemical substances used intentionally in the agriculture. Both are important sources of soil pollution. 

Pesticides as pollutants. By pesticides we mean substances for the suppression and destruction of harmful organisms. Pesticides are used particularly in plant production. Originally, mainly inorganic substances were used. Most of them are also used currently, particularly in the form of salts or oxides. However, advances in organic chemistry led to the industrial production of ever more relatively inexpensive synthetic organic substances characterized by their extraordinary efficiency. The first of these was dichlorodiphenyltrichloroethane (DDT), which became commercially available as an insecticide in 1942. At the present time, organic pesticides are in wide-spread use. 

Depending on their function or purpose, the pesticides may be categorized as follows  

Some preparations may exert combined effects from the standpoint of this classification. 

The pesticides are produced as application preparations marketed in the form which facilitates the application on the area treated in the dose necessary. For spraying the treated area, they are in the form of liquid emul-sifiable or powdered suspended concentrates. In this way, certain amounts of solvents and filling agents are also transported into the environment. These are particularly different mineral oils, tensides and in small aerosol products also freons. In some countries experiments are also aimed at the possibility of using certain antibiotics as pesticides. 

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