Environmental Pollution

Definition
Gaseous, liquid, or solid substances which (when present in sufficient concentration, for a sufficient time, and under certain conditions) tend to interfere with human comfort, health or welfare, and cause environmental damage. Air pollution causes acid rain, ozone depletion, photochemical smog, and other such phenomenon.
Pollution in broad terms may be defined as an undesirable change in physical, chemical or biological characteristics of air, water and land that may or will harmfully affect human lives, lives of desirable species, living conditions or will deteriorate raw materials resources.Pollutions are substances, chemicals or factors which cause adverse effect on natural quality of any constituent of environment. Pollutions are generally bye products or waste - products.

Types of pollution

There are 7 (seven) types of pollution that are going to be discussed in this note, namely air, water, noise, land, radioactive, marine and thermal. Please proceed to the following links to learn anyone of them.

1. Air Pollution
2. Water Pollution
3. Land Pollution
4. Noise Pollution
5. Radioactive Pollution
6. Thermal Pollution
7. Marine Pollution

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Air Pollution
Air pollution is the presence of materials in air in such concentration which are harmful to man and his environment. Various causes of air pollution are:
Category
1. Chemical plants
Examples: Petroleum refineries, fertilizers, cements, papermills, ceramic clay products, glass manufacture
Important pollutants: H2S, sulphur oxide, fluorides, organic vapours and dust
2. Crop spraying
Examples: Pesticides and weedicides
Important pollutants: Organophosphates, chlorinated hydrocarbons, lead, arsenic
3. Fuel burning
Examples: Domestic burning, thermal power plants
Important pollutants: Sulphur and nitrogen oxides
4. Metallurgy plants
Examples: Aluminium refineries and steel plant
Important pollutants:Metal flumes (Pb and Zn) fluorides and particulates
5. Nuclear device testing
Examples: Bomb explosions
Important pollutants:Radioactive fall out, Sr-90, Cs-137, C-14 etc.
6. Ore preparations
Examples: Crushing, grinding and screening
Important pollutants: Uranium and beryllium dust, other particulates
7. Spray painting, ink, solvent cleansing
Examples: Printing and chemical separations, furniture, dyeing
Important pollutants: Hydrocarbons and other organic vapours
8. Transportation
Examples: Cars, trucks, aeroplanes and railways
Important pollutants: CO, NO, NO2, Pb, smoke, soot, smoke organic vapours etc.
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2. Water Pollution

Water pollution aversely changes he quality of water. It degrades the quality of water so that it either becomes health hazard or unfit for use. Surface water is never pure. Soil erosion, leaching of minerals from rocks, decaying of organic matter are natural sources of water pollution. Most of water pollution is man-made

Effects of Water Pollution (a)Eutrophication is a natural process observed in lakes and tanks where rich growth of micro-organisms consumes much of dissolved oxygen, depriving other organisms. It is generally found at bottom layers of deep lakes. Addition of excessive plant nutrients increases Eutrophication and is harmful to fish and other aquatic life.
(b) Foam formation in waters by soaps, detergents and alkalies.

(c) Impairment of taste and unpleasant odours in water.
(d) Turbidity which makes water unfit for drinking and industrial purpose.
(e) Inorganic nitrates and phosphates stimulate excessive plant growth in lake and reservoirs


Control of Water Pollution
1. Water hyacinth can purify water polluted by biological and chemical wastes.
2. Strict legislation should be enacted over industries to treat waste water before being discharge into rivers or series.
3. Reclaiming polluted water by proper sewage treatment plants.
4. Domestic and industrial wastes should be destroyed by constructing composite pit.
5. Hot water should be cooled suitably before adding to river water.
6. Oxidation ponds can be used in removing low level of radioactive wastes.
7. Sewage pollutions are subjected to chemical treatment to change them into non-toxic substances.
8. Very specific and less stable chemicals should be used in manufacture of insecticides to reduce water pollution.

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Soil Pollution

Soil pollution is standing up as an havoc in densely populated and developing countries. Since soil-formation is slow it is regarded as non-renewable resource. Soil pollution is the effect of dumping and disposal of wastes, application of agrochemicals or indirect result of air pollution (acid rain). Pesticides reduce the population and number of species of living organisms which effect structure and fertility of the soil. Several pesticides and their degradation products enter the food chain via. plants.

Improper sanitation and unhygienic practices of the people of developing countries pollute the soil. Innumerable pathogens present in these wastes contaminate the vegetable crops and cause several health hazards for man and domesticated animals. Biological sources are a minor factor in altering soil composition.

Control of Soil Pollution
1. Use of pesticides should be minimized.
2. Use of fertilisers should be judicious.
3. Cropping techniques should be improved to prevent growth of weeds.
4. Special pits should be selected for dumping wastes.
5. Controlled grazing and forest management.
6. Wind breaks and wind shield in areas exposed to wind erosin
7. Planning of soil binding grasses along banks and slopes prone to rapid erosin.
8. Afforestation and reforestation.

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Noise Pollution

Noise is defined as 'unwanted sounds' being 'dumped' into atmosphere to disturb the unwilling ears. It effects our physiological and mental health. A sound of over 115 decides is harmful for ears. They city noise is often sufficient to deafen people gradually, at least partially with advancing age. Sources of Noise Pollution High intensity sound from industrial machines, supersonic aeroplanes, bomb blasts, exploding of crackers, blaring radios and loudspeakers, slogans shouting city crowd, traffic noise etc.

Effects of Noise Pollution
1. It interferes with human communication
2. Prolonged exposure leads to deafen our ears or permanent loss of hearing.
3. It causes anxiety, reaction of stress and tension, may produce fright and even heart failure to heart patients.
4. Its long exposure can cause hormonal imbalance leading to adverse disorders like increased heart beat, constriction of blood vessels, increase in cholesterol level, high blood pressure and hypertension and production of gastro intestinal problems like peptic ulcers.
5. It can impair development of nervous system of unborn babies leading to abnormal behaviour in life.

Control of Noise PollutionIt depends upon three factors:
1. To reduce the source of noise.
2. To put checks in path of its transmission.
3. To safeguard the receive of the noise. For this to happen vehicular traffic should be diverted away from dwelling sites. Proper designing of machines can reduce loss due to noise. Acoustic furnishing (absorbing techniques) should be extensively employed. There should be legal enforcement of restrictions on noise pollution.

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Radioactive Pollution

Despite the advantage of nuclear as a clean energy, the big concern is the waste resulted from nuclear reaction, which is a form of pollution, called radioactivity. Radioactivity is a form of radiation (a form of energy that travels through space). Some elements in this world are naturally radioactive while some others are made to be. Radioactivity is emitted when a radioactive element become unstable and begin to decay in the attempt to regain their molecular stability. When an element decays, it emits energy and small particles. If it’s still radioactive, it will repeat the process, until it finally regains its molecular stability and stop decaying. The time that it takes for half way of decaying process is called half-life, and this differs for each radioactive element. It possibly takes up to 4.5 billion years (Uranium 238) and as short as 8 days (Iodine 131). This process constantly remains, not considering external factors such as pressure or temperature.

There are commonly three types of radiation, namely:

Alpha particles, can be blocked by a piece of paper and human skin.

Beta particles can penetrate through skin, while can be blocked by some pieces of glass and metal.

Gamma rays can penetrate easily to human skin and damage cells on its way through, reaching far, and can only be blocked by a very thick, strong, massive piece of concrete.

We can classify major sources that lead to radioactive pollution to the following categories:
· nuclear power plants
· nuclear weapon
· transportation
· disposal of nuclear waste uranium mining

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Thermal Pollution:

It is caused by addition of hot effluents and hot water bodies. Warm water contains less oxygen. So there is decrease in rate of decomposition of organic matter. Green algae are replaced by less desirable blue green algae. Many animals fail to multiply. Trout eggs fail to hatch while salmon does not spawm at higher temperature.Agriculture sources.Use of high yielding varieties of crops increased the demand for fertilizers are carried to ground water by leaching. They are also added through surface run off. Many pesticides are non-degradable. Huge amount of animal excreta-dung, piggeries are either discharged into grazing fields or dumped into pits.

These are later carried either by surface run-off or get percolated into under-grounded water. Lack of potable drinking water supply, unhygienic habits and poor waster disposal have aggravated problem of water pollution. To evade water pollution regulations and to avoid cost of treatment, industries are disposing off their wastes on ground which has lead to large scale pollution of underground water.

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Marine Pollution.

Oceans are ultimate sink of all natural and man-made pollutants. Marine ecosystems lack decomposing capacity. Artificial discharges cause localised pollution especially in coastal areas. Main sources are navigational oil discharge, grease and petroleum products, detergents, sewage and garbage including radioactive wastes.