Biology project – Pollution

INTRODUCTION
Pollution is the introduction of harmful materials or we can say
contaminants into the environment. These harmful materials are
called pollutants. Pollutants can be natural, such as volcanic ash as
well as man made, such as trash or runoff produced by factories.
Pollutants damage the quality of air, water, and land.

Many things that are useful to people produce pollution.

Cars spew pollutants from their exhaust pipes. Burning coal to
create electricity pollutes the air. Industries and
homes generate garbage and sewage that can pollute the land and
water. Pesticides—chemical poisons used to kill weeds and insects
—seep into waterways and harm wildlife.

All living things—from one-celled microbes to blue whales—

depend on Earth’s supply of air and water. When these resources
are polluted, all forms of life are threatened.

Pollution is a global problem. Although urban areas are usually

more polluted than the countryside, pollution can spread
to remote places where no humans exist.
 Types of pollution
There are three major types of pollution:

1. Air pollution
2. Water pollution
3. Soil pollution

Now we would be knowing about all these in detail.

Air pollution
Air pollution takes place when chemicals contaminate the atmosphere
affecting its structure and composition and producing significant
harmful effects on human health, animals, vegetation and environmental
quality.

Sources of air pollution

Sources of air pollution can be classified according to their origin:

• anthropogenic (man-made) sources, which are the result of various

human activities. For example: The smoke emitted from various
forms of combustion like in biomass, factories, vehicles,
furnaces, etc.

Waste used to create landfills generate methane, which is

harmful in several ways. The reactions of certain gases and
chemicals also form harmful fumes that can be dangerous to
the well being of living creatures.
 • natural sources include dust carried by the wind from
locations with very little or no green cover, gases released
from the body processes of living beings (Carbon dioxide from
humans during respiration, Methane from cattle during
digestion, Oxygen from plants during Photosynthesis). Smoke
from the combustion of various inflammable objects, volcanic
eruptions, etc along with the emission of polluted gases also
makes it to the list of natural sources of pollution.

Contaminants can also be classified as:

• primary pollutants, such as sulphur dioxide or nitrogen monoxide,

which are directly emitted into the atmosphere from its sources;

• secondary pollutants, as ozone, which are formed as a result of

chemical reactions in the atmosphere.

Concequences of air pollution

1. Respiratory and heart problems

The effects of air pollution are alarming. They are known to

create several respiratory and heart conditions along with
Cancer, among other threats to the body. Several million are
known to have died due to the direct or indirect effects of Air
pollution. Children in areas exposed to air pollutants are said
to commonly suffer from pneumonia and asthma.
 2. Global warming

Another direct effect is the immediate alterations that the

world is witnessing due to global warming. With increased
temperatures worldwide, an increase in sea levels and melting
of ice from colder regions and icebergs, displacement, and
loss of habitat have already signaled an impending disaster if
actions for preservation and normalization aren’t undertaken
soon.

3. Effect on wildlife

Just like humans, animals also face some devastating effects of

air pollution. Toxic chemicals present in the air can
force wildlife species to move to a new place and change their
habitat. The toxic pollutants deposit over the surface of the
water and can also affect sea animals.

4. Depletion of the ozone layer

Ozone exists in the Earth’s stratosphere and is responsible for

protecting humans from harmful ultraviolet (UV) rays. Earth’s
ozone layer is depleting due to the presence of
chlorofluorocarbons, hydrochlorofluorocarbons in the
atmosphere.

As the ozone layer will go thin, it will emit harmful rays back on

earth and can cause skin and eye-related problems. UV rays
also have the capability to affect crops.
 And the list goes on………

How to control air pollution??

The use of solar, wind and geothermal energies reduce air
pollution at a larger level. Various countries including India have
implemented the use of these resources as a step towards a
cleaner environment.
Other air pollution control measures include:

1. Use the public mode of transportation. Encourage people

to use more and more public modes of transportation to
reduce pollution. Also, try to make use of carpooling.

2. Switch off fans and lights when you are going out. A
large number of fossil fuels are burnt to produce
electricity. You can save the environment from
degradation by reducing the number of fossil fuels to be
burned.

3. Understand the concept of Reduce, Reuse and Recycle.

4. Since industrial emissions are one of the major causes of

air pollution, the pollutants can be controlled or treated at the
source itself to reduce its effects.

5. Fuel substitution is another way of controlling air pollution. In

many parts of India, petrol and diesel are being replaced by CNG
– Compressed Natural Gas fuelled vehicles.
6. A very effective way of controlling air pollution is by diluting the
air pollutants.

7. The last and the best way of reducing the ill effects of air
pollution is tree plantation. Plants and trees reduce a large
number of pollutants in the air.

Several attempts are being made worldwide on personal,

industrial, and governmental levels to curb the intensity at
which air pollution is rising and regain a balance as far as the
proportions of the foundation gases are concerned.

We are seeing a series of innovations and experiments aimed

at alternate and unconventional options to reduce pollutants.
Air pollution is one of the larger mirrors of man’s follies, and a
challenge we need to overcome to see a tomorrow.

Water pollution
Water is uniquely vulnerable to pollution. Known as a “universal
solvent,” water is able to dissolve more substances than any other
liquid on earth. It’s the reason we have Kool-Aid and brilliant blue
waterfalls. It’s also why water is so easily polluted. Toxic
substances from farms, towns, and factories readily dissolve into
and mix with it, causing water pollution.
Water pollution occurs when harmful substances—often
chemicals or microorganisms—contaminate a stream, river, lake,
ocean, aquifer, or other body of water, degrading water quality
and rendering it toxic to humans or the environment.

Sources of water pollution

There are various classifications of water pollution. The two
chief sources of water pollution can be seen as Point and
Non-Point.

Point refers to the pollutants that belong to a single

source. An example of this would be emissions from factories
into the water.

Non-Point, on the other hand, means pollutants emitted

from multiple sources. Contaminated water after rains that
has traveled through several regions may also be considered
as a Non-point source of pollution.

Causes of water pollution

1. Industrial waste

Many industries do not have a proper waste

management system and drain the waste in the fresh
water which goes into rivers, canals and later into the sea. The
toxic chemicals thus, contaminate the fresh water

2. Sewage and wastewater

The sewage and wastewater that is produced by each
household is chemically treated and released into the sea with
fresh water. The sewage water carries harmful bacteria and
chemicals that can cause serious health problems

3. Accidental oil leakage

Oil spill poses a huge concern as a large amount of oil enters

into the sea and does not dissolve with water; thereby opens
problem for local marine wildlife such as fish, birds and sea
otters.

4. Chemical fertilizers and pesticides

Chemical fertilizers and pesticides are used by farmers to

protect crops from insects and bacterias. They are useful for
the plant’s growth. However, when these chemicals are mixed
up with water pose serious damages for aquatic animals.

And many more…….

Consequences of water pollution

Infectious diseases can be spread  through contaminated water.
Some of these water-borne diseases are Typhoid, Cholera,
Paratyphoid Fever, Dysentery, Jaundice, Amoebiasis and Malaria. 

Chemicals in the water also have negative effects on our health. 

Pesticides  –  can damage the nervous system and cause cancer

because of the carbonates and organophosphates that they
contain. Chlorides can cause reproductive and endocrinal
damage.

Nitrates  –  are especially dangerous to babies that drink formula

milk. It restricts the amount of oxygen in the brain and cause the
“blue baby” syndrome.

Lead  –  can accumulate in the body and damage the central

nervous system. 

Prevention of water pollution

1. Conserve water by turning off the taps when not in use.
2. Mind what you throw down your sink or toilet.
3. Don’t throw paints and oils in water channels.
4. Use environment friendly household products, such as
washing powder, household cleaning agents, etc.
5. Take great care not to overuse fertilizers and pesticides.
6. Don’t throw litter into rivers, lakes or oceans. Help clean
up any litteryou see on beaches or in river and lakes,
make sure it is safe to collect the litter and put it in a
nearby dustbin.

Soil pollution
 Soil pollution is defined as the presence of toxic
chemicals (pollutants or contaminants) in soil, in high
enough concentrations to pose a risk to human health
and/or the ecosystem. In the case of contaminants which
occur naturally in soil, even when their levels are not high
enough to pose a risk, soil pollution is still said to occur if
the levels of the contaminants in soil exceed the levels
that should naturally be present.

Sources of soil pollution

1. Agricultural sources

Agricultural practices such as the use of non-organic products

in crop and livestock production lead to soil pollution. 

2. Industrial sources

Industrial wastes or byproducts are among the leading

causes of soil pollution. They can be in the form of gas, liquid,
or solid substances.

3. Deforestation

Though not a direct contributing factor to soil

pollution, deforestation leads to the removal of the shield that
protects the soil against the agents of erosion. The exposed
soil is easily eroded and exposed to artificial
chemical pollutants from the air, wind, and rain.

4. Urban waste
Most developing countries have a problem controlling the
disposal of municipal garbage. The garbage is dumped
anyhow and contains wastes such as food waste, plastics,
industrial wastes, e-waste, and general household wastes.

5. Nuclear sources

Improper disposal of wastes from nuclear plants can,

therefore, result in soil pollution and contamination.

Consequences of soil pollution

 Since the volatile contaminants in the soil can be carried
away into the atmosphere by winds or can seep into
underground water reserves, soil pollution can be a direct
contributor to air and water pollution.
 It can also contribute towards acid rain (by releasing huge
quantities of ammonia into the atmosphere).
 Acidic soils are inhospitable to several microorganisms that
improve soil texture and help in the decomposition of organic
matter.
 Crop yield is greatly affected by this form of pollution. In
China, over 12 million tons of grain (worth approximately 2.6
billion USD) is found to be unfit for human consumption due
to contamination with heavy metals (as per studies
conducted by the China Dialogue).

Prevention of soil pollution

To prevent soil pollution, its causes must be controlled.
1. Reduce the use of plastics: Plastics and polythene bags destroy the
fertility of the soil. Hence, these should be disposed off properly and if
possible, their use should be avoided.
2. Industrial pollutants: Some waste products from industries and homes
pollute the soil. These pollutants should be treated chemically to make
them harmless before they are disposed off.
3. Insecticides: Other pollutants of soil include pesticides and insecticides. 
4. Use manures instead of chemical fertilizers.
5. Industrial waste should be treated before release.
Therefore, the excessive use of these substances should be avoided.

3 major consequences of pollution

Now I would like to discuss the three major consequences of air, water
and soil pollution.

Acid rain, Smog and Global warming

Acid rain
Acid rain describes any form of precipitation with high levels of nitric
and sulphuric acids. It can also occur in the form of snow, fog, and tiny
bits of dry material that settle to earth

Effects

Acid rain makes water acidic and causes it to absorb the aluminium that
makes its way from soil into lakes and streams. Thi combination makes
water toxic to the aquatic life.

Smog
Smog is a type of air pollution which reduces visibility. The term
“smog” was first used in the early 1900s to describe a mix of smoke and
fog. The smoke usually came from burning coal. Smog was common in
industrial areas, and remains a familiar site in cities today.

Effects

Smog is unhealthy to humans and animals, and it can kill plants. Smog is
also ugly. It make the sky brown or grey. It is common in big cities with
a lot of industries and traffic. Cities located in basins surrounded by
mountains may have smog problems because the smog is trapped in the
valley and can’t be carried away by wind.

Global warming
Global warming is a term used for the observed century-scale
rise in the average temperature of the Earth's climate
system and its related effects. Scientists are more than 95%
certain that nearly all of global warming is caused by
increasing concentrations of greenhouse gases (GHGs) and
other human-caused emissions.

Effects

The effects of global warming or climate damage include far-

reaching and long-lasting changes to the natural
environment, to ecosystems and human societies caused
directly or indirectly by human emissions of greenhouse
gases. It also includes the economic and social changes
which stem from living in a warmer world.