Soil Pollution

Soil Pollution – Causes of Soil Pollution , Effects of Soil Pollution and control of soil pollution

what is soil

Soil definition : Soil, the uppermost layer of the earth’s crust is a mixture of many solid, liquid and gaseous substances having both living and non living matter such as mineral particles, decaying organic matter, microbes along with water and air contained in pore spaces. 

soil is an important natural resource, formed over the centuries that supports the variety of plants and provides habitat for various microscopic and macroscopic life-forms apart from other ecological functions. 

Formation of soil

Formation of soil is a very slow process starting from weathering (Breakdown of bed rock into mineral particles) to soil development i.e. pedogenesis (modification of mineral matter through interactions between biological, topographic and climatic factors). It may take 200 to some thousand years to form an inch of top soil depending upon the local conditions of the area.

Composition of soil is listed below:

Components in SoilPercentage
Organic mineral matter45%
Organic matter05%
Soil water25%
Soil air25%

What is Soil Pollution

Soil Pollution Definition : 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. 

Soil pollution Also known as Land Pollution, this occurs due to incorporation of unwanted chemicals in the soil due to human activities. Soil pollution depicts the contamination of soil due to the presence of toxic substances such as excessive use of fertilizers and pesticides , deforestation industrial waste etc. Food is a big contributor to landfill waste.

Sources of Soil Pollution

Soil Pollution is caused by :

  • Industrial wastes 
  • Modern Agricultural Practices
    • Pesticides
  • Urban Wastes
  • Radioactive Pollutants
  • Biological Agents
  • Accidental Oil Spills
  • Acid Rain

Causes of Soil Pollution

  • Industrial Wastes : Disposal of industrial wastes is the important source of soil pollution. Industrial pollutants are mainly discharged from chemical industries, sugar factories, tanneries, textile mills, steel industries, distilleries, pulp and paper mills, oil refineries, petroleum industries etc. Thermal and atomic power plants also add pollutants to the soil.
    • Effect :- These pollutants affect and alter the chemical and biological properties of soil. As a result, hazardous chemicals can enter into human food chain from the soil or water, disturb the biochemical process and finally lead to serious effects on living organisms.
  • Agricultural Wastes : Agricultural wastes are the common pollutants of soil pollution. Fertilizers, pesticides, insecticides, weedicides etc. cause soil pollution and adversely affect the physical, chemical and biological properties of soil.
    • Pesticides :- Pesticides are chemicals that include insecticides, fungicides, algaecides, rodenticides, weedicides sprayed in order to improve productivity of agriculture, forestry and horticulture. Pesticides not only bring toxic effect on human and animals but also decrease the fertility of the soil. Some of the pesticides are quite stable and their bio- degradation may take weeks and even months.
  • Urban Wastes : Urban wastes consist of both commercial as well as domestic wastes which include plastics, glasses, metallic cans, fibres, paper, rubbers, street sweepings, fuel residues, leaves, containers, abandoned vehicles and other discarded manufactured products etc. and contribute to soil pollution.
  • Radioactive Pollutants : Radioactive substances resulting from explosions of nuclear testing laboratories, radioactive fallout and industries giving rise to nuclear dust and radioactive wastes penetrate the soil and accumulate giving rise to soil pollution. 
    • Example :- Nuclear reactors produce waste containing Cesium-144 and strontium-90 along with Strontium-90 and cesium-137 have half-lives of about 30 years (half the radioactivity will decay in 30 years). Plutonium-239 has a half-life of 24,000 years.
  • Biological Agents : Other important soil pollutants are biological agents which include biological organisms from human and animal excreta. In addition to this, faulty sanitation and disposal of waste water cause soil pollution.
  • Accidental Oil Spills : Oil leaks can happen during storage and transport of chemicals. This can be seen at most of the fuel stations. The chemical present in the fuel deteriorates the quality of soil and make them unsuitable for cultivation. These chemicals can enter into the groundwater through soil and make the water undrinkable
  • Acid Rain : Acid rain is caused when pollutants present in the air mixes up with the rain and fall back on the ground. The polluted water could dissolve away some of the important nutrients found in soil and change the structure of the soil.

Effects of Soil Pollution

It causes harmful effect on the soil and the environment. Contamination of soil will decreases the agricultural output. Major soil pollution effects are :

Effects of Soil Pollution on Agriculture

  • Reduced soil fertility
  • Reduced nitrogen fixation 
  • Increased erodibility 
  • Larger loss of soil and nutrients 
  • Deposition of silt in tanks and reservoirs 
  • Reduced crop yield 
  • Imbalance in soil fauna and flora

Decreased Crop Quality : It can decrease the quality of the crop. Regular use of chemical fertilizers, pesticides will decrease the fertility of the soil at a rapid rate and alter the structure of the soil. This will lead to decrease in soil quality and poor quality of crops. Over the time the soil will become less productive due to the accumulation of toxic chemicals in large quantity.

Effects of Soil Pollution on Human health

Effect on Human Health : Considering how soil is the reason we are able to sustain ourselves, the contamination of it has major consequences on our health. It will increase the exposure to toxic and harmful chemicals thus increasing health threats to people living nearby on the degraded land. Living, working or playing in the contaminated soil can lead to respiratory diseases, skin diseases, and other diseases. Moreover, it can cause other health problems.

Short term effects on Human health

  • headache
  • nausea and vomiting
  • chest pain
  • coughing and lung problems
  • fatigue
  • skin rash
  • eye irritations

Contamination of Water Sources

The surface run-off after raining will carry the polluted soil and enter into different water resource. Thus, it can cause underground water contamination thereby causing water pollution. This water after contamination is not fit for human as well as animal use due to the presence of toxic chemicals.

Negative Impact on Ecosystem and Biodiversity

Soil pollution can cause an imbalance of the ecosystem of the soil. The soil is an important habitat and is the house of different type of microorganisms, animals etc. Thus, soil pollution can negatively impact the lives of the living organisms and can result in the gradual death of many organisms. It can cause health threats to animals grazing in the contaminated soil or microorganisms residing in the soil.

Control measures

  • Reducing chemical fertilizer and pesticide use
  • Use of bio pesticides, bio fertilizers.
  • Organic farming
  • Four R’s: Refuse, Reduce, Reuse, and Recycle
  • Afforestation and Reforestation
  • Solid waste treatment
  • Reduction of waste from construction areas

Prevention of Soil Pollution 

  • Reducing chemical fertilizer and pesticide use : Applying bio-fertilizers and manures can reduce chemical fertilizer and pesticide use. Biological methods of pest control can also reduce the use of pesticides and thereby minimize soil pollution.
  • Production of natural fertilizers : Bio-pesticides should be used in place of toxic chemical pesticides. Organic fertilizers should be used in place of synthesized chemical fertilizers. Ex: Organic wastes in animal dung may be used to prepare compost manure instead of throwing them wastefully and polluting the soil.
  • Proper hygienic condition : People should be trained regarding sanitary habits. Example :- Lavatories should be equipped with quick and effective disposal methods.
  • Reusing of materials : Materials such as glass containers, plastic bags, paper, cloth etc. can be reused at domestic levels rather than being disposed, reducing solid waste pollution.
  • Recycling and recovery of materials : This is a reasonable solution for reducing soil pollution. Materials such as paper, some kinds of plastics and glass can and are being recycled. This decreases the volume of refuse and helps in the conservation of natural resources. For example, recovery of one tonne of paper can save 17 trees.
  • Reforesting : Control of land loss and soil erosion can be attempted through restoring forest and grass cover to check wastelands, soil erosion and floods. Crop rotation or mixed cropping can improve the fertility of the land.
  • Ban on Toxic chemicals : Ban should be imposed on chemicals and pesticides like DDT, BHC, etc which are fatal to plants and animals. Nuclear explosions and improper disposal of radioactive wastes should be banned.
  • Public awareness : Informal and formal public awareness programs should be imparted to educate people on health hazards by environmental education. 
    • Example :- Mass media, Educational institutions and voluntary agencies can achieve this.
  • Education : Education is an important tool that needs to be utilized in order to help people to understand the best way to use the land. By educating them on sustainable practices, more land will be saved from being getting polluted.
  • Solid waste treatment : Proper methods should be adopted for management of solid waste disposal. Industrial wastes an be treated physically, chemically and biologically until they are less hazardous. Acidic and alkaline wastes should be first neutralized; the insoluble material if biodegradable should be allowed to degrade under controlled conditions before being disposed.
    • As a last resort, new areas for storage of hazardous waste should be investigated such as deep well injection and more secure landfills. Burying the waste in locations situated away from residential areas is the simplest and most widely used technique of solid waste management. Environmental and aesthetic considerations must be taken into consideration before selecting the dumping sites. 

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