The contamination of soil with acid rain, fertilizer, insecticide and pesticide residue, metals like Pb from exhausted petrol, sulphate, nitrates, etc is known as soil pollution. Soil is the acceptor of large quantities of waste products that may be a domestic, human, animal, industrial and agricultural.
The combustion of sulphur containing fuels emits SO2 and finally leaves sulphate on the soil. Fertilizers, pesticides, insecticides, herbicides applied to the crops are largely retained by the soil. Industrial products such as plastics, rubbers, glasses, tin and similarly toxic wastes like waste oil, lubricants, acid tars, lacquers, etc are deposited on the soil. Such pollutants destroy soil quality.
Sources of soil pollution
- Industrial products: large percentage about 15.2% of pollutants includes from industrial productions like rubber, plastics, toxic substances, chemicals, sewage, glasses, dust, waste oil, paints, decay row materials, etc directly mix into sources of water and spread over fertile land through irrigation
- Agricultural: Residues of pesticides, herbicides and unconsumed fertilizers largely retained by the soil surface day by day due to their heavy use. After a certain year, fertile lands are converting into sterile and become bare land which causes land slide, flooding, soil erosion, etc.
- Domestic: It includes the garbage from houses and other premises such as un-degradable domestic wastes like containers, pieces of bottles, plastics, glasses, gasoline, polythene, etc. Such domestic pollutants take a large part in the pollution of soil in developing countries like Nepal. There are no safe and accessible dumping sites as well as strict rules-regulation by the government. So, domestics pollutant is not controlling and managed in our country due to which as a result soil is pollution is increasing rapidly. About 8.5% soil pollutants are from domestic and trade.
- Volcanic eruption: Metallic oxides, sulphate residues, and other tarry liquids. Solid tarry matters are spread over the soil surface and cover a large areas.
- Mining and quarrying: It contains about 67% soil pollutants like rock particles, heap of wastes from quarries and tarry liquids like seam of coal, acid tars, waste oil, etc from mining.
- Toxic substances: Tarry liquids, Pb containing gasoline sludge, water-kerosene mixture, acid tars, bases and cyanide wastes. Different organic solvent etc are toxic matters
- Construction: Various construction works such as the construction of roads, buildings, tunnels, bridges, etc are the sources of the soil pollutants. Construction work consists about 2% pollutants.
Effects of Soil Pollution
- It destroys the fertile land
- Affect the health of people through fruits ,vegetables and crops
- Decreases the production rate of crops, grains.
- It causes soil erosion and flooding.
- It direct effect habitats of human, forest, grassy lands and hilly regions.
Controls measure of soil pollution
- By replacing use of insecticides, fungicides by biological methods of control.
- Controlled by advising and applying manure rather the use of chemical fertilizers.
- By dumping domestic, industrial and chemicals.
- By advising to apply lead free gasoline
- Controlled by recycling the domestic materials.