Soil pollution occurs through direct sources like waste disposal and indirect sources like acid rain. It harms soil quality and plant/animal health. Common direct causes are poor management of domestic, industrial, and agricultural waste, as well as soil erosion. Indirect causes include acid rain and radioactive waste disposal. Pesticides, faulty agricultural practices, and industrial/domestic solid wastes are major pollution sources. Effects include reduced fertility, water contamination, and release of toxic gases. Control methods center around reducing waste, using natural fertilizers and pesticides, afforestation, legislation, proper disposal, and soil remediation.

2. “Soil pollution can be defined as the introduction of
substances, biological organisms, or energy into the
soil that will lead to a change in the quality of soil
so that plant growth and animal health is
adversely affected.”

3.  Soil pollution is caused due to direct and indirect sources.
 The direct sources harm the soil much more than the indirect
sources.
 Examples of direct causes are poor management of solid and liquid
domestic/industrial/agricultural waste, water logging, soil erosion,
salination, disposal of medical wastes etc.
 Examples of indirect causes are acid rain and disposal of radioactive
substances.

4.  The main reasons of soil pollution are briefly described below:
 (i) Pesticides: pesticides are the chemicals which are used by farmers to
protect their crops. Large amounts of pesticide in soil interfere with the soil
metabolic process. Pesticides kill many non-targeted beneficial soil organisms
such as earthworms. Thus, the soil becomes infertile.
 Organo-chlorides (like dichloro diphenyl trichloroethane, DDT) are second
generation pesticides. They are non-biodegradable substances. They
accumulate and magnify in the food chain and interfere with the calcium
metabolism of birds. As a consequence, birds lay fragile, thin-shelled eggs.
 High concentration of pesticides get accumulated in fatty tissues of prey
organisms. When predators eat these prey organisms, they also get killed.
 Thus, pesticides lead to poisoning of the ecosystem.

5.  The main reasons of soil pollution are briefly described below:
 (ii) Faulty agricultural practices:
 (a) Unskilled irrigation: Water logging may occur when the drainage system
of the agricultural field is not maintained scientifically. Water logging closes
the passage of air to the soil, stops the growth of soil organisms and make the
soil barren.
 (b) Shifting cultivation: In it, the forest is burnt to use the land for cultivation.
However, this practice exposes the soil for soil erosion.
 (c) Injudicious use of chemical fertilizers: Use of inorganic fertilizers increases
the nutrient contamination. The microbes of the soil reduce the nitrogen to
nitrite ions which enter the animal body through food, or water. It is directly
absorbed in the blood stream and oxidize the oxyhaemoglobin (the O2 carrier)
to methemoglobin. The later cannot carry oxygen any more so ultimately
animal dies.

6.  The main reasons of soil pollution are briefly described below:
 (iii) Solid wastes from homes and industries: Chemical, petroleum, and metal-
related industries, dry cleaners and gas stations produce hazardous waste
such as oils, battery metals and organic solvents. These hazardous waste
contaminate soil and water resources.
 (iv) Acid rain: It converts neutral soil to acidic one.

7.  The harmful effects of soil pollution are briefly described below:
 (i) Reduction in the fertility of soil.
 (ii) Obstruction in the public passage (road, railway lanes etc.) by solid waste.
 (iii) Contamination of underground and surface drinking water.
 (iv) Fluorosis occurs as a result of consumption of fluoride containing maize,
jawar crops. The fluoride is absorbed by the crops from the fluoride
contaminated soil.
 (v) Emission of toxic gases (from dumped solid wastes on land) are
detrimental to health.
 (vi) The unpleasant smell and spread of insects cause inconvenience to people.
 (vii) Poisoning of the ecosystem take place by soil pollution.
 (viii) Soil erosion occurs due to shifting cultivation.

8.  The land pollution can be controlled by following methods:
 (i) Planned afforestation helps in preventing soil erosion.
 (ii) Use of biofertilizers and natural pesticides help in minimizing usage of
chemical fertilizers and pesticides.
 (iii) The principles of three Rs, namely, Recycle, Reuse and Reduce help in
minimizing generation of solid waste.
 (iv) Formulation and effective implementation of stringent pollution control
legislation also helps in controlling soil pollution.
 (v) Proper disposal methods must be employed. For example, composting of
biodegradable solids and incineration of non-biodegradable solids should be
done.

9.  The land pollution can be controlled by following methods:
 (vi) Proper treatment of liquid wastes from industries and mines must be
done.
 (vii) Faulty sanitation practices must be improved.
 (viii) Polluted soil can be treated by bioremediation. It uses microorganisms
(yeast, fungi or bacteria) to breakdown, or degrade, hazardous substances into
less toxic or non-toxic substances (such as CO2 and H2O).