Environmental Pollution.pptx

- Dr Binod Rajak
Unit-3: Environmental Pollution

Environmental + Pollution
Pollution is derived from Latin word ‘polluere’ which means ‘to
contaminate’ any feature of environment.
Pollution is the effect of undesirable changes in our surroundings that have
harmful effects on plants, animals and human beings.
This occurs only when short term economic gains are made at the cost of
long-term ecological benefits of humanity.
Environmental pollution is defined as an undesirable change in the
physical, chemical and biological characteristics of any component of the
environment (water, soil, air) that can cause harmful effect on various forms
of life and property.
Pollution can be primary (effects immediately on release to the
environment) or secondary (product of interaction after release with
moisture, sunlight, other pollutants etc.
Pollution may be local, regional, transboundary or global.
The agent which causes pollution is called pollutant.

Pollutants can be classified as:
Degradable or non-persistent pollutants: These can be rapidly
broken by natural processes. E.g., Domestic sewage, discarded
vegetables etc.
Slowly degradable or persistent pollutants: These remain in the
environment for many years in an unchanged condition and take
decades or longer to degrade. E.g.: DDT
Non degradable pollutants: These cannot be degraded by natural
processes. E.g.: Toxic elements like lead or mercury and nuclear
wastes

Agents Causing Pollution
Depending upon the nature of the pollutants and their interaction with
environment process, the pollution caused by different agents can be
classified into the following categories:
(a) Pollution caused by solid wastes.
(b) Pollution caused by liquid wastes.
(c) Pollution caused by gaseous wastes.
(d) Pollution caused by wastes without weights.

Pollution caused by Solid wastes:
• The solid wastes includes the pollutants like garbage, rubbish, ashes, large wastes formed
due to demolition and construction processes, dead animals wastes, agricultural wastes
etc.
• From the above examples, it is clear that the solid wastes may be domestic and industrial
in nature.
Pollution caused by liquid wastes:
• Oxygen cycle is nicely operated in aquatic system maintaining ecological balance.
• That is, the dissolved oxygen is used by aquatic living organisms for their respiration and
in return, these liberate carbon dioxide.
• Carbon dioxide molecules are again used by green plants and algae in the process of
photosynthesis.
• During photosynthesis, oxygen is again liberated to water which remains in dissolved
state. However, if some organic matter (food for bacteria) enters the water course, then
bacteria oxidise these materials consuming oxygen from water.
• At such a condition, if the process of re oxygenation is slower than the process of de-
oxygenation, then the river will be devoid of life sustaining dissolved oxygen and aquatic
living organisms will die.
• The most important source of organic pollutants is sewage which contains faecal matter,
urine, kitchen washing and oil washings. Sewage also contains a large number of
pathogenic and harmless bacteria.

Pollution caused by Gaseous Wastes:
• The gaseous wastes include Carbon monoxide (CO), Sulphur dioxide
(SO2), nitrogen dioxide (NO2), Ozone (O3) and smog gases
(composed of a complex mixture of photochemical oxidation products
of hydrocarbons).
• These gases are more abundant in the atmosphere of industrial cities.
Pollution from Waste without weight:
• This type of pollution is also known as pollution by energy waste;
Wastes without weight may be of the following types:
(i) Radio-active
(ii) Heat
(iii) Noise

(i) Radio-active Substance:
Despite of all possible precautions in the functioning and maintenance of
nuclear reactors, it is seen that minute quantity of radio-active waste escapes
out into the environment. From the mining operation of the uranium to the
use and final disposal of wastes from the reactor, radio-active materials
continuously escape out into the environment. Besides, a lot of radio-active
wastes enter into environment during the nuclear tests.
(ii) Heat:
A large quantity of waste heat energy is dissolute into environment by the
way of hot liquid streams or hot gases released by industries and automobiles.
(iii) Noise:
The unwanted sound is known as noise. This sources of noise for the general
public are the machines in the industry, traffic noise, indiscriminate use of
transistor, radios, public address systems, etc.

Air pollution
Air pollution occurs due to the presence of undesirable solid or gaseous particles
in the air in quantities that are harmful to human health and environment.
It can be defined as presence of foreign matter either gaseous or particulate or
combination of both in the air which is detrimental to the health and welfare of
human beings.
Pollutants that are emitted directly from identifiable sources are produced by
natural events can be in the form of particulate matter or gaseous form.
These are called primary pollutants Ex: Dust storms and volcanic eruptions and
through human activities like emission from vehicles, industries etc.
There are five primary pollutants that contribute to 90% of global air pollution.
carbon oxides (CO and CO2), nitrogen oxides, sulfur oxides, volatile organic
compounds (mostly hydrocarbons), and suspended particulate matter (SPMs).
The pollutants that are produced in the atmosphere, when certain chemical
reactions take place among the primary pollutants and with others in the
atmosphere are called secondary air pollutants.

Causes of Air pollution
Air pollution may originate from one or more variety of sources.
The natural pollution includes sources such as oceanic aerosol,
volcanic emissions, biogenic sources, windblown terrestrial dust and
lightening.
The artificial pollution generates from human activities and includes
sources such as fuel burning, refuge burning, transportation,
construction of buildings, chemical factories, metallurgical factories
and vehicles.
The third category includes solvent usage and sources include spray
painting and solvent extraction. Automobiles are the first rate of
polluters. Industries occupy second position.

Effects of Air Pollution on health
• Cigarette smoking is responsible for greatest
exposure to carbon monoxide (CO).
• Exposure to air containing even 0.001% of CO for
several hours can cause collapse, coma and even
death.
• As CO remains attached to hemoglobin in the
blood for a long time, it accumulates and reduces
the oxygen carrying capacity of blood.
• This impairs thinking, causes headaches,
drowsiness and nausea.
• SO2 irritates the respiratory tissues.
• NO2 can irritate lungs, aggravate asthma and
susceptibility to influenza and common colds.
• Many volatile organic compounds (benzene and
formaldehyde) and toxic particulates can cause
mutations and cancer.

Others effects
• Sulfur oxides- very dangerous to humans at a high concentration.
• Sulfur in the atmosphere is responsible for acid rain.
• CO2 is a good transmitter of sunlight, but it also partially restricts infrared
radiation going back from the earth into space, which produces the so-
called greenhouse effect that prevents a drastic cooling of the Earth during
the night.
• CO2 in atmosphere --> GLOBAL WARMING
• Sun burn, cataract, aging of skin and skin cancer are caused by increased
UV radiation.
• It weakens the immune system by Volcanic emissions supporting the body’s
resistance to certain infections like measles, chickenpox & other viral
diseases.
• Contribute to global warming, a phenomenon which is caused due to the
increase in concentration of certain gases like CO2, NO2 methane and
chlorofluorocarbons (CFCs).

• When the quality or composition of water changes directly or
indirectly as a result of man’s activities such that it becomes unfit for
any useful purpose is said to be polluted.
Two types of pollutions:
• Point source of pollution: This source of pollution can be readily
identified because it has a definite source and place, where it enters the
water. e.g., Municipal industrial discharges pipes.
• Non-point source of pollution: when a source of pollution cannot be
readily identified such as agricultural runoff, acid rain etc, it is called
as non-point source of pollution.

Causes of water pollution: (surface water)
Disease causing agents parasitic worms, bacteria, viruses, protozoa that enter water from
domestic sewage and untreated human and animal wastes.
Oxygen depleting wastes: These are organic wastes that can be decomposed by aerobic
bacteria. The amount of oxygen required to break down a certain amount of organic
matter is called BOD. It is an indicator of level of pollution.
Inorganic plant nutrients: There are water soluble nitrates and phosphates
Excess pesticides: For control of pest pesticides are used in discriminately. These fall on
ground and leach with rain water to canals and rivers.
Water soluble organic chemicals: These are acids, salts and compounds of toxic metals
such as mercury & lead.
Variety of organic chemicals: includes oil, gasoline, plastics, pesticides, detergents &
many other chemicals.
The sediments of suspended matter: Occur when soil is eroded.
Water soluble radioactive isotopes: Enter the water courses along with rain water.
Hot water released by power plants & industries that use large volume of water to cool
the plant results in a rise in temp of local water bodies.
Acid drainage into rivers.

Ground water pollution: A greater threat to human life comes from the
pollution of ground water which is used for drinking and irrigation being
polluted.
Causes of ground water pollution:
1. Urban runoff of untreated or poorly treated waste water storage and
garbage
2. Industrial waste storage located above or near aquifer
3. Agricultural practices such as application of large amounts of fertilizers
and pesticides, animal feeding operations etc in rural sector
4. Leaks from underground storage tanks containing gasoline and other
hazardous substances
5. Poorly designed and inadequately maintained septic tanks
6. Mining waters

Effects of Water pollution
1. Large amount of human waste in water increase the number diseases i.e., diarrhea, typhoid etc.
2. If more organic matter is added to water the O2 is used up. This causes fish and other forms of O2
dependent aquatic life dies.
3. Eutrophication due to inorganic pollutants.
4. Excess pesticides cause Biomagnification.
5. High levels of organic chemicals (acids, salts& toxic metals) can make the water unfit to drink,
harm fish and other aquatic life, reduce crop yields
6. Variety of organic chemicals / oil gasoline, plastics detergents) are harmful to aquatic life and
human life
7. Sediments (erosion), clog the lakes and artificial reservoirs
8. Radioisotopes cause birth defects, cancer and genetic damage.
9. Hot water cause thermal pollution
10. Hot water because of thermal pollution not only decrease the solubility of O2 but also changes
the breeding cycles of various aquatic organisms.
11. Accidental oil spills cause environmental damage.

• Land pollution is the demolition of Earth's land surfaces often
caused by human activities and their misuse of land resources.
It occurs when waste is not disposed properly.
• Urbanization and industrialization are major causes of land
pollution.

Causes of Land Pollution
Construction
Agriculture
Industrial Waste
Soil is formed from the parent material
by physical and chemical weathering of
rocks.
Climate and time are also important in
the development of soils.
Extremely dry or cold climates develop
soils very slowly while humid and warm
climates develop them more rapidly.
It is a thin covering over the land
consisting of a mixture of minerals,
organic material, living organisms, air
and water that together support the
growth of plant life.

Effects of Soil Pollution
a) Food shortage: The foremost effect of losing top soil is causing water pollution
and reduced food production leading to food shortage. With population growth, it
becomes more critical.
b) Desertification: Continuous exposure of eroded soil to sun for longer periods
may transform the land into sandy and rocky in nature. These are symptoms of
desertification rendering the soil unsuitable for cultivation.
c) Decrease in the extent of agricultural land
d) Top soil which is washed away also contributes water pollution by clogging of
lakes, and increasing turbidity of water, ultimately leading to loss of aquatic life.
e) Sedimentation is reservoirs reduces the storage capacity inform causes reduction
in command area.
f) Excess use of irrigation leads to waterlogging and soil salinisation.
g) Fertilizer run off leads to the eutrophication of waterways.

Thermal Pollution
• Thermal pollution is the degradation
of water quality by any process that
increases the ambient water
temperature.
• The increase in temperature
• (a) decreases the dissolved
oxygen/oxygen supply, and
• (b) affects ecosystem composition.

Effects
• The warmer temperature decreases the solubility of oxygen and increases
the metabolism of fish.
• Tropical marine animals are generally unable to withstand a temperature
increase of 2 to 30C and most sponges, mollusks and crustaceans are
eliminated at temperatures above 370C.
• When a power plant first opens or shuts down for repair or other causes,
fish and other organisms adapted to particular temperature range can be
killed by the abrupt rise in water temperature known as 'thermal shock’.
• Elevated temperature typically decreases the level of dissolved oxygen
(DO) in water.
• The decrease in levels of DO can harm aquatic animals such as fish and
amphibians.
• Increase in toxicity

Marine Pollution
• Marine pollution is defined as the
introduction of substances to the
marine environment directly or
indirectly by man resulting in adverse
effects such as hazardous to human
health, obstruction of marine
activities and lowering the quality of
sea water.

1. Municipal waste & sewage from residences and hotels in coastal towns are directly discharged into sea
2. Pesticides and fertilizers from agriculture which are washed off by rain enter water courses & finally to
sea. India is estimated to use 55,000 tons of pesticides annually and about 25 percent of it is carried to
ocean.
3. Petroleum & oil washed off from roads normally enter sewage system & finally into seas
4. Ship accidents & accidental spillage at sea can therefore be very damaging to the marine environment.
5. Off shore oil exploration also pollutes the sea water to a large extent.
6. Dry docking: All ships periodic dry-docking servicing; cleaning the hulls etc. during this period when
cargo compartments are emptied, residual oil goes into sea.
7. Pollution due to organic wastes: When O2 concentration falls 1.5 mg/l, the rate of aerobic oxidants
reduced and replaced by the anaerobic bacteria that can oxidize the organic molecules without the use of
oxygen.
8. Tanker accidents: In the natural process, a large number of oil tanker accidents happen every year.
Sometimes this can result in major disasters.
9. Volcanic eruptions in the sea.
10. Deep Sea mining is a relatively new mineral retrieval process that takes place on the ocean floor.
Ocean mining sites are usually done at about 1,400 - 3,700 meters below the ocean’s surface.

Noise Pollution
• Noise may not seem as harmful as the
contamination of air or water, but it is a
pollution problem that affects human
health and can contribute to a general
deterioration of environmental quality.
• Noise is undesirable and unwanted sound.
• It may be considered as music to one
person and may be noise to another.
• Noise is defined as ‘unwanted or offensive
sound that unreasonably intrude into our
daily activities’.
• Sound is measured in a unit called the
decibel (dB).
• The permitted noise level is 125 decibels
as per the Environment Protection Rules
1999.

Effects of noise pollution
Emotional or psychological effects - irritability, anxiety and
stress. Lack of concentration and mental fatigue are significant
health effects of noise.
It has been observed that the performance of school children is
poor in comprehension tasks when schools are situated in busy
areas of a city and suffer from noise pollution - disturbance.
Interferes with normal auditory communication, it may mask
auditory warning signals and hence increases the rate of accidents
especially in industries.
The effects can range in severity from being extremely annoying
to being extremely painful and hazardous Lowers workers
efficiency and productivity and higher accident rates on the job.

Environmental Pollution.pptx

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