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Old Saturday, June 20, 2020
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Post Environmental Pollution

One of the major threats that our environment is facing today is environmental pollution, increasing with every passing year and causing grave and irreparable damage to the atmosphere. The mechanization of society, the urbanization, introduction of motorized vehicles, and the explosion of the human population have caused an exponential growth in the increase of waste by-products. The indiscriminate discharge of untreated industrial and domestic wastes into waterways, the "throwaway" attitude towards thousands of tons of solid wastes and other particulates into the atmosphere have resulted in major environmental disasters.

What is Environmental Pollution?

Environmental pollution is any discharge of material or energy into water, land, or air that causes or may cause acute (short-term) or chronic (long-term) detriment to the Earth's ecological balance or that lowers the quality of life in the environment.


Environmental pollution is the introduction of contaminants into a habitat that causes harm, instability, disorder or discomfort to the living organisms in the habitat.


Pollutants can be classified as primary or secondary.

Primary pollutants are substances that are directly emitted into the atmosphere from sources. The main primary pollutants known to cause harm in high enough concentrations are the following:
• Carbon compounds, such as CO, CO2, CH4,
• Nitrogen compounds, such as NO, N2O, and NH3
• Sulfur compounds, such as H2S and SO2
Halogen compounds, such as chlorides, fluorides, and bromides
• Particulate Matter either in solid or liquid form.
Secondary pollutants are not directly emitted from sources, but instead form in the atmosphere from primary pollutants (also called “precursors”). The main secondary pollutants known to cause harm in high enough concentrations are the following:
• NO2 and HNO3 formed from NO
• Ozone (O3) formed from photochemical reactions of nitrogen oxides
• Sulfuric acid droplets formed from SO2, and nitric acid droplets formed from NO2
• Sulfates and nitrates aerosols
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Types of Pollution:

There are three main classes of the Environmental pollution:
(1) Air pollution :
The condition in which air contains harmful substances (chemicals, particulate matter or biological), gases, dust, fumes or odour in harmful amounts and causes discomfort to living beings and environment is called Air pollution.
Factors responsible for air pollution refer to the various activities or sources which are responsible for the releasing of pollutants into the atmosphere.

These sources can be classified into two major categories which are:

(a). Natural Factors/Sources:

The natural factors responsible for air pollution refer to the various activities or sources which occur naturally and are responsible for the releasing of pollutants into the atmosphere.

1. Volcanic Eruption:
On global scale most of the Suphurdioxide is produced by Volcanoes which is bout 67%. These volcanic eruptions are also responsible for Carbon Monoxide emission.

2. Bacterial Action:

Various bacterial actions produce Nitrogen Oxides, of which main is Nitrogen Monoxide.
Anaerobic decomposition of organic matter by bacteria in water sediments and in soils is the natural source of methane and methane.

3. Trees and Plants:

Large quantities of hydrocarbons are emitted by different trees and plants in the atmosphere. This methane can remain in atmosphere upto average 3-7 years.

(b). Anthropogenic Factors/sources:

The factors which contribute to air pollution due to human activity are called anthropogenic sources. Following are some factors:

1. Burning of different kinds of fuels:

Air pollution is cause by the injurious smoke emitted by automobiles, stacks of power plants, furnaces and incinerators and factories namely sulphur dioxide, carbon monoxide and nitrogen oxides. The emissions from vehicles are estimated to be responsible for approximately 60% of all air pollution alone The smoke from burning wood, dung and cigarettes is also harmful to the environment causing a lot of damage to man and the atmosphere.

2. Use of Paints and enamel:

The use of paint, varnish, aerosol sprays and other solvents has been common practice nowadays. This also causes generation of harmful off-gasing and unwanted fumes from things such as paint and plastic production which pollute natural air causing irritation.

3. Chlorofluorocarbons (CFC):

It is released from refrigerators, air-conditioners, deodorants and insect repellents and cause severe damage to the Earth’s environment. This gas has slowly damaged the atmosphere and depleted the ozone layer leading to global warming.

4. Waste deposition in landfills:

This process generates methane. Although methane is not much toxic; however, it is highly flammable and may form explosive mixtures with air. Methane is also an asphyxiant and may displace oxygen in an enclosed space which may result in suffocation if the oxygen concentration is reduced to below 19.5% by displacement.

5. Military/Defence Military Practices:

Various military weapons and instruments like nuclear weapons, missiles, rockets, toxic gases, germ warfare etc used for defence and strategic purpose have also contributed to air pollution.
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(2) Water pollution:

Water pollution could be in the form of any change in the physical, chemical and biological properties of water which has a harmful effect on living things. It could take place in various water sources, like ponds, lakes, rivers, seas and oceans.
The factors that cause water pollution are as follows:

1. Industrial Waste Effluents:

Many of the chemical related and manufacturing industries like leather tanneries, fertilizers, oil refineries, petrochemical, textile, paper pulp, rubber products and agrochemicals are always generating by-products and waste effluents along with their desired products. The waste product may be in the form of waste heat, smoke, solid or waste water effluents. These may contain organic chemicals including highly toxic synthetic organic compounds and heavy metals i.e. Pb, Cd, Cr, Hg, As, Sb etc, oils, greases, mineral acids. These may result in contamination of both surface and ground water. Unfortunately, many industries release their waste products directly into rivers or let them leak into the groundwater and increasing water pollution. These chemicals are poisonous or toxic to plants, animals and people.

2. Pesticides:

Pesticides are organic and inorganic chemicals originally invented and used effectively for controlling undesirable insects and forms of life such as bacteria, pests, and foraging insects. Their effectiveness, however, has caused considerable pollution. The persistent or hard pesticides, which are relatively inert and non-degradable by chemical or biologic activity, are also bio-accumulative; that is why they are retained within the body of the consuming organism. The drainage water from the agricultural land (where pesticides are being used) mostly contains pesticides and pollutes water system not only at surface level but also at ground level due to leaching of pesticide.

3. Insecticides:

Insecticides are chemicals that are sprayed onto crops to kill the insects that eat crops. One of the more poisonous insecticides are DDT and organo-phosphates. Some specialists believe that these insecticides have caused even greater environmental damage and that they are more toxic. Insecticides are easily washed by the excess water and rain into streams and groundwater where they poison fish and domestic animals and also pollute food chain.

4. Fungicides:

Copper and mercury are two heavy metals, which are found in fungicides. Fungicides are also sprayed on crops and easily washed into rivers. These heavy metals are toxic to biological life including the people who may have to drink from the polluted water bodies.

5. Heavy Metals:

Heavy metals such as nickel, molybdenum, zinc, cadmium and lead are mined and processed by the mining and ore-smelting industries. These metals are easily washed into streams and groundwater and increase pollution. The crops that have been irrigated with polluted water can also be dangerous.
In the past, toxic waste products were dumped into the rivers or into landfill sites close to where people lived causing health problems and even death. Today all South Africans have a constitutional right to a clean and safe environment. Make sure that you remain informed and observant so that you can prevent toxic chemicals from being used in your environment. If you suspect water pollution in your area then contact your local council.

6. Oil Spills and transport:

Petroleum products are used as fuel, lubricants, for manufacturing petrochemicals, plastics, electrical appliances, synthetic rubbers and detergents. Sea water gets polluted by accidental oil spills and leakage from cargo oil tankers in sea, tanker trucks, pipelines leakage during offshore exploration and leakage of underground storage tanks. The spilled oil also damages marine life often causing their death.

7. Chlorine and Detergents:

Paper and pulp mills and textile factories are amongst the worst water polluters. Paper and pulp mills use up large amounts of water and produce a lot of polluted wastewater. The wastewater contains strong chemicals such as chlorine, which is used to make paper white and soft. Textile factories also release strong chemicals like caustic soda, acids, dyes and detergents into water.

8. Detergents:

Detergents are excessively used in industries and household as cleaning agents. The amount of disposed detergents in waste water is increasing day by day. This waste water when discharged in rivers or sea greatly affects aquatic life. The detergent contents of waste water mobilize the bound toxic ions of heavy metals like Pb, Cd and Hg from sedimentary rock into water.

9. Fertilisers and Sewage:

Some chemicals like fertilisers are made up of substances that do occur naturally in the environment, but only in small amounts. When too much fertiliser is washed from farmlands into a river then that water will also become polluted. Human sewage or cattle excrement that is untreated also causes water pollution in the same way as fertilisers do.
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(3) Soil Pollution:

Soil pollution or soil contamination, is a condition that occurs when soil loses its structure, biological and chemical properties due to the use of various synthetic chemicals and other natural changes in the soil environment. Factors often believed to contribute to soil pollution include the use of chemicals such as acid rain, fertilizers, the salinity of the soil and environmental changes. Some of the most common factors causing soil pollution are elucidated and discussed at length below:

1. Oil Spills:

The accidental oil spills and leakage from cargo oil tankers, tanker trucks and pipelines pollute soil in the sense that the fertility status of the land becomes greatly compromised after an oil spill.

2. Use of salty water:

The use of water with a high salinity i.e. water that contains higher amounts of salts such as sodium chloride [NaCl], adversely affects the soil as well as the crop growth. The salts present in the water accumulate in the top layer of the soil, resulting in decreased growth of crops and decreased yields, and ultimately making the soil and the land unfit for crop yielding and other agricultural practices.

3. Heavy Metal

Soil pollution by heavy metals is most often the result of mining, manufacturing and improper disposal of man-made products, including paint, batteries and pesticides. Exposure is most often chronic, occurring over an extended period of time. Nickel, copper, chromium and manganese are also widespread contaminants, each with its own list of health effects. Additionally, most heavy metals have carcinogenic effects.

4. Polychlorinated Biphenyls:

Polychlorinated biphenyls (PCBs) are completely man-made products common in manufacturing processes and equipment, including coolants, transformers, capacitors and motors. In the 1970s Congress banned them as a persistent organic pollutant, the cause of numerous environmental contamination sites now considered unlivable, including Superfund sites in Massachusetts, New York, Indiana and the Great Lakes.

5. Poor agricultural practices:

Soil erosion--a result of poor agricultural practices--removes rich humus topsoil developed over many years through vegetative decay and microbial degradation and thus strips the land of valuable nutrients for crop growth.

6. Use of chemicals on soil and agricultural crops:

Excessive use of chemicals such as pesticides, insecticides and fertilizers is one of the prime factors causing soil pollution. These chemicals adversely affect the soil by increasing its salinity and making it imperfect for crop bearing. It also affects the microorganisms present in the soil, causing the soil to lose its fertility and resulting in the loss of minerals present in the soil, thus causing soil pollution.

7. Mineral exploitation:

Environmentally unfriendly mineral exploitation practices and srip mining for minerals, gas and coal reserves lays waste thousands of acres of land each year, denuding the Earth and subjecting the mined area to widespread erosion problems. Soil erosion not only despoils the Earth for farming and other uses, but also increases the suspended-solids load of the waterway. This increase interferes with the ecological habitat and poses silting problems in navigation channels, inhibiting the commercial use of these waters.

8. Solid waste:

Among the most significant environmental problems, one is the enormous volume of solid waste which is being produced every day but not be disposed properly. The mismanagement of the solid waste, particularly the polythene shopping bag has caused serious threat to the soil. The most common and convenient method of disposing of municipal solid wastes is in the sanitary landfill present greater environmental hazards. In the landfills, non-biodegradable materials like plastic bottles, Styrofoam and cans can remain buried and intact for thousands of years, leaching chemicals into the ground over the years. Groundwater infiltration and contamination of soil with toxic chemicals is the result.

9. Urbanization and Industrialization:

The increase in urbanization due to population pressure presents additional soil-erosion problems. The industrial runoff has also contributed a lot in polluting topsoil and regular disposal of waste effluent leaches to soil and degrades it not only making land barren but also pollutes groundwater.
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