Pollution is the addition of pollutants to the ecosystem, which has a detrimental effect on it. The most important causes of pollution are the high rate of energy usage by modern, growing populations. Pollution is the contamination of air, water, or land by harmful substances that interfere with human health, the quality of life, or the natural functioning of ecosystems. The pollution is caused by the agent which cause an imbalance in the earth’s ecological equilibrium.

Pollution exists in many forms.

• POINT SOURCE POLLUTION comes from specific, localized, and identifiable sources, such as sewage pipelines or industrial smokestacks.
• NONPOINT-SOURCE POLLUTION comes from dispersed or uncontained sources, such as contaminated water runoff from urban areas or automobile emissions.

Pollution is caused by two sources

• NATURAL POLLUTION – Natural pollution occurs naturally. It doesn’t cause much harm due to its regeneration ability.
• MAN MADE POLLUTION – Man made pollution is caused by human activities. The main cause of man-made pollution is human population and technology.

There are two main categories of pollutants.

• BIODEGRADABLE POLLUTANTS – Biodegradable pollutants are materials, such as sewage, that rapidly decompose by natural processes. These pollutants become a problem when added to the environment faster than they can decompose.
• NONDEGRADABLE POLLUTANTS – Nondegradable pollutants are materials that either do not decompose or decompose slowly in the natural environment. It is difficult to remove these pollutants from the environment.

Types of Pollution:

1. Air Pollution.
2. Water Pollution.
3. Land Pollution.

AIR POLLUTION

atmosphere due to excess emission of gases into the atmosphere, a saturation of chemical compounds and the emergence of new chemical reactions of reactive and non-biodegradable compounds.

Sources of Air Pollution

1. Heat and power generation facilities.
2. Industrial processes.
3. Auto manufacturing.
4. Fertilizers plants.
5. Building demolition.
6. Solid waste disposal.
7. Solvent evaporation.
8. Fuel production.
9. Roadway construction.
10. Motor vehicle exhaust.

Effect of Air Pollution

Global Warming – Air pollution causes global warming. It is an increase in Earth’s temperature due to the buildup of certain atmospheric gases such as carbon dioxide. Carbon dioxide and other gases reduce the escape of heat from the earth’s atmosphere without blocking radiation coming from the Sun. Because of this, average global temperatures are expected to rise 1.4 to 5.8 Celsius degrees by the year 2100.

Acid Rain – Air pollution causes acid rain. The pollutants in the atmosphere contain sulfur and nitrogen oxides, which are converted into acids that mix with rain. This acid rain falls in lakes and on forests, where it can lead to the death of fish and plants, and damage entire ecosystems.

Smog – Air pollution in urban areas is commonly known as smog. It is the smoky mixture of carbon monoxide and organic compounds from incomplete combustion (burning) of fossil fuels such as coal, and sulfur dioxide from impurities in the fuels. The smog reacts with oxygen, organic and sulfuric acids condense as droplets, increasing the haze. This smog is caused by combustion in a car, truck, and airplane engines, which produce nitrogen oxides and release hydrocarbons from unburned fuels. The chemical smog caused by exhaust fumes from cars and industrial pollution of the air kills thousands of people.

Ozone Depletion – Air pollutants contain hydrocarbons and sulfur and nitrogen oxides. Sunlight causes the nitrogen oxides and hydrocarbons to combine and turn oxygen into ozone, a chemical agent that attacks rubber, injures plants, and irritates lungs.

Damaging Atmospheric Region – Air pollution can also damage the upper atmospheric region known as the stratosphere. Excessive production of chlorine-containing compounds such as chlorofluorocarbons (CFCs) (compounds formerly used in refrigerators, air conditioners, and in the manufacture of polystyrene products) has depleted the stratospheric ozone layer, creating a hole above Antarctica. Due to the exposure to the Sun’s harmful rays, the aquatic and terrestrial wildlife has been damaged and there is a threat to human health in high-latitude regions of the northern and southern hemisphere.

Control of Air Pollution

* Establishment of smokeless zones.
* Control over the kinds of fuel used in cars, airplanes and power stations.

WATER POLLUTION

Water pollution is the contamination of water by foreign matter that deteriorates the quality of the water. Water pollution occurs in the oceans, lakes, streams, rivers, underground water and bays. It involves the release of toxic substances, pathogenic germs, easy-soluble substances, radioactivity, etc. that become deposited upon the bottom and their accumulations will interfere with the condition of aquatic ecosystems.

Source of Water Pollution

The source of water pollution is closely connected to human activity namely:

• Domestic Pollution includes sewage wastes.
• Urban Pollution includes.
• Industrial Pollution includes Synthetic chemicals, Heavy metals.
• Agricultural Pollution includes Sediment, Excess organic matter, fertilizers.

Nature of Water Pollution

• Physical pollution- There is the presence of suspended material in water.
• Chemical pollution- There is the presence of dissolved material in water.
• Biological pollution- There is the presence of bacteria, viruses, and fungi in water.
• Thermal pollution-There is a rise in the temperature of water.

Causes of Water Pollution

• Sewage
• Industrial wastes
• Agricultural chemicals such as fertilizers and pesticides.

Effect of Water Pollution

Water runoff carries fertilizing chemicals such as phosphates and nitrates from agricultural fields into lakes, streams, and rivers. These combine with the phosphates and nitrates from sewage and speed up the growth of algae. The water body becomes choked which depletes the oxygen supply. This process is called eutrophication. It causes the death of fish and other aquatic life.

Soil erosion also contributes to water pollution. Soil washed from logged hillsides, plowed fields, or construction sites, clog waterways and kill aquatic vegetation.

Water pollution exists in the forms of petroleum. Petroleum often pollutes water bodies in the form of oil, resulting from oil spills. Exxon Valdez is an example of this type of water pollution. Offshore drilling operations contribute a large share of pollution.

Water pollution exists in the form of radioactive substances. It is produced in the form of waste from nuclear power plants, the industrial, medical, and scientific use of radioactive materials. Specific forms of waste are uranium and thorium mining and refining.

The other form of water pollution is heating. Heat is a pollutant because increased temperatures result in the deaths of many aquatic organisms. These decreases in temperatures are caused when a discharge of cooling water by factories and power plants occurs.

Pollution in the form of organic material enters rivers and ponds in the form of sewage as leaves, or as runoff from livestock feedlots and pastures. When bacteria and protozoan in the water break them down, they begin to use up the oxygen dissolved in the water. Many types of fish and bottom-dwelling animals die when levels of dissolved oxygen drop. As a result, many aquatic organisms are killed, which leads to disruptions in the food chain.

Water pollution is also caused by Pathogens that prove very harmful. They can cause many illnesses like typhoid and dysentery to minor respiratory and skin diseases. Pathogens include such organisms as bacteria, viruses, and protozoan. These pollutants enter waterways through untreated sewage, septic tanks, and agricultural runoff.

Control of Water Pollution

* Everyone should be wise enough not to pollute water.
* By research and legislation the pollution of water bodies can be prevented and controlled.

LAND POLLUTION

Land pollution is the degradation of the land surface by

• Misuse of the soil by poor agricultural practices.
• Mineral exploitation.
• Industrial waste dumping.
• Indiscriminate disposal of urban wastes.

The addition of undesirable matter to the land

1. Damages the terrestrial organisms.
2. Reduces the uses of the land by man.
3. Increases the risk of health hazards to man.

Land pollution includes:

1. Solid waste.
2. Soil Pollution.

Solid Waste

Litter is waste material dumped in public places such as streets, parks, and picnic areas, at bus stops and near shops. The accumulation of waste threatens the health of people in residential areas. Waste decays encourage household pests and turn urban areas into unsightly, dirty and unhealthy places to live in. Disposal of solid or semisolid materials, resulting from human and animal activities, that are useless or hazardous are called solid waste. Solid wastes include:

• Garbage: Decomposable wastes from food and non-decomposable wastes, either combustible such as paper, wood, and cloth or noncombustible such as metal, glass.
• Ashes: Residues of the combustion of solid fuels.
• Sewage-treatment solids: Wastes retained on sewage-treatment, settled solids, and biomass sludge.
• Industrial wastes: Materials such as chemicals, paints.
• Mining wastes: Slag heaps and coal refuse piles.
• Agricultural wastes: Wastes from farm, animal manure and crop residues.

Soil Pollution

Soil pollution is mainly due to chemicals in herbicides (weed killers) and pesticides (poisons which kill insects and other invertebrate pests). The soil gets polluted because of:

• Unhealthy soil management methods.
• Improper irrigation practices.

Farms can cause land pollution by allowing manure to accumulate and leach into nearby ground. Chemicals such as those used in sheep dipping have also caused serious incidents on farms and diesel oil spills are a relatively common danger.

Sources of Land Pollution

Poor Agriculture practices which includes

1. Accumulation of animal manures.
2. Excessive use of chemical fertilizers.
3. Dumping of tainted crops on land.
4. Agricultural run-off.

Mining and quarrying involves

1. Excessive use of explosives to blow up mines.
2. Excessive use of machineries which emits toxic substances in the soil.

Household wastes involves

1. Improper disposal of waste causes waste accumulation.
2. Improper sanitation system.

Demolitions and constructions waste

1. Non biodegradable rubbles debris which are left uncleared, settle down in the soil and leads to soil toxicity.

Industrial waste

1. Toxic emissions of gases from the industries.
2. Construction debris.
3. Petroche mical contamination from transport and fuels.
4. Heavy metals and chemicals.

Effects of Land Pollution

Land pollution can have many effects on humans, plants, animals, and wildlife.

• Skin problems.
• Respiratory problems.
• Birth defects.
• Cancers.

Toxic pollutants can get into our bodies directly through

• Skin contact.
• Breathing in particles or dust.
• Eating vegetables grown in contaminated soil.
• Wash into water sources such as rivers and reservoirs.

Prevention

* We should be particular that our litter is disposed of properly.
* The domestic items should either be reused if possible or recycled.
* Anti-litter campaigns can educate people against littering.
* Organic waste can be dumped in places far from residential areas.
* Inorganic materials such as metals, glass, and plastic, but also paper, can be reclaimed and recycled.

We should use different methods to reduce waste. These methods are:

1. Resource Recovery Plant Generates Energy from Garbage: Several companies burn in-plant wastes in conventional incinerators to produce steam. Garbage is converted to useful energy in the solid waste plant. The plant generates energy. Steam produced drives a turbine on a generator, and the energy from the generator is converted for use in the city.
2. Recycling includes Shredding, Magnetic separation of metals, Air classification that separates light and heavy fractions, Screening and Washing.
3. Wet pulping process Incoming refuse is mixed with water and ground into the slurry. The slurry is loaded into a centrifuge called a liquid cyclone. The resulting materials go to a paper-fiber-recovery system. The final residue is used as landfill.
4. Refuse-collection organizations. Special trucks pick up the waste and transfer it to recycling facilities, thus lessening the load at incinerators and landfills.