Soil or land pollution can be defined as the “changes in physical, chemical and biological conditions of the soil through man’s intervention/misuse of land and hence resulting in degradation in quantity and productivity of the soil.
Causes of Soil Pollution:
Domestic and municipal waste, industrial waste and agricultural waste are responsible for soil pollution in UDCs. Not only land but fresh water and local marine environment are also polluted.
(a) Domestic and Municipal Wastes:
Domestic wastes are those wastes which are generated by households. These wastes include many substances and materials like peels of fruits and vegetables, unused food products, newspapers and plastics which are dumped into soil. These are not properly disposed off and become a home for rats, flies and mosquitoes etc.
(b) Industrial Wastes:
The main sources of soil pollution are such industries as oil refineries, chemicals and fertilizers, food processing, iron and steel, pulp and paper, textile and mining, etc. Lakhs of tonnes of industrial wastes are dumped into soil, thus enhancing the extent of soil pollution.
(c) Agricultural Pollution:
Irrigation increases salinity of the soil to such a level that its productivity decreases. Intensive use of fertilizers results in the loss of ability to fix nitrogen. Pesticide residues remain in soil for a long time.
(d) Mineral Production:
Mineral production is always associated with the solid waste generation in the form of overburden, tailings and slimes. Areas around smelting and mining complexes are usually soiled by metals. Mining results in soil erosion, loss of fertile land and also soil pollution.
(e) Biological Agents:
The problem of improper excreta disposal can be the cause of soil pollution, water pollution, and propagation of flies. The diseases which can occur due to pollution are typhoid and paratyphoid fever, dysentery, diarrhea, cholera, hookworm diseases, ascariasis, viral hepatitis and a host of other intestinal infections.
(f) Radioactive Substances:
Nuclear wastes are harmful because they contain radioactive substances which emit nuclear radiation. If these radioactive nuclear wastes are dumped in garbage bins, they will emit nuclear radiations and pose a threat to the life of men and animals.
Effects of Soil Pollution:
Soil pollution affects human beings, animals and vegetation alike:
1. Soil pollution is a major pollution problem with significant economic implications. Domestic and industrial wastes cause pollution of the soil and land degradation. There is water pollution from dumping and runoffs follow. Some disposal practices such as burning, cause air pollution problems to human beings.
2. Quality and variety of crops are affected when grown on polluted land. Mining results in soil erosion, loss of fertile land and also soil pollution.
3. The problem of improper excreta disposal can be the cause of soil pollution, water pollution and propagation of flies. The human and animal excreta is a source of infection and diseases. The disease is transmitted through various channels such as water, flies, soil and food.
Measures to Control Soil Pollution:
The goal of integrated soil management is to optimize the combination of economic and environmental benefits.
(a) Adaptation of Sustainable Agriculture Management Techniques:
(i) It emphasizes on rational use of organic manure.
(ii) The garbage produced should be burnt in closed chambers.
(iii) Identification of land planning units for determining land use options, potential long-term economic returns, nutrient inputs and outputs and environmental impacts.
(iv) Implementation of afforestation programmes.
(b) Sustainable Waste Management:
It includes the following steps:
(i) Industrial wastes should be recycled.
(ii) Debris and wastes left after mining should be refilled in old and abandoned mines.
(iii) Composting of biodegradable materials should be done.
(iv) Public awareness has to be created.