Pollution
Pollution has been defined by
Odum (1971) as “the undesirable
change in the physical, chemical or biological characteristics of air, land and
water that may affect the human life. The pollutants cause undesirable physical
and biological changes. Pollution is caused due to pollutants.
POLLUTANTS:
Odum defines
pollutant as “residues of things we make, use and threw away are called
pollutants. Pollutants may be solid, liquid or gaseous substances and are the
residues of things we make, use and throwaway. There are many sources of such
pollutants. Lakes and rivers are polluted by wastes from chemical and other
factories and the air by gases of automobile exhausts, industries, thermal
power plants etc The pollutants may be:
·
The pollutant may be gases like CO, SO2 etc.
·
These may be metals like lead, zinc, chromium
etc.
·
There may be industrial pollutants like cyanide
compounds, acetic acid acids.
·
Agriculture pollutants are pesticides,
herbicides, fungicides and fertilizers.
·
Photochemical pollutants are ozone oxides, CFC
(Chloroouro carbon).
·
Radiations from radioactive substance also act
as pollutants
·
Noise: Horns, loudspeakers etc.
·
Municipal waste: Sewage, solid waste etc.
·
Fluorides: Fluorides
·
Deposited matter: Soot, smoke, tar, dust, grit
etc.
There are two types
of pollutants:
Nondegradable pollutants:
The pollutants which are not degraded or degraded at very slov, rate are
called Nondegradable pollutants. These are mostly inorganic compounds like
metallic oxides. DDT etc.
Biodegradable pollutants:
The pollutants which are degraded by microorganism are called
biodegradable pollutants. These include domestic sewage. There are different
types of pollutions, air, water, soil etc.
There are several kinds of pollutions which pollute our
environment. But the major types are: Air pollution, water pollution, land
pollution, noise pollution etc.
NOISE
POLLUTION
The
ability to make and detect sound enables humans to communicate with each other
as well as to receive useful information from the environment. We all hear
sound produced by vehicles, trains, aeroplanes, industries, community functions
etc. All these produce noise which is most dangerous pollutant of man's
environment. Noise has become a permanent part of our lives in these days.
Noise not only harms to our brain but it also affects the important internal
organs of the body. It not only causes irritation but constricts our arteries,
increases blood pressure and heart beats etc.
The noise can be
defined as 'the unwanted sound or
unpleasant sound which causes discomfort'.
It may also defined as the wrong sound at the' wrong place at the wrong time.
The unwanted sound forced into the atmosphere leads to health hazards. Noise is
measured in decible (dB). Pain is usually felt at 145 dB. People begin to
complain when unwantd sound reaches a level of upto 100 dB.
In the past, the noise was limited to the industries only,
but these days there has been a rapid industrial growth, population explosion,
heavy traffic, urban crowding etc. All these have added the noise nuisance in
the environment. Besides these, social and religious functions increase the
gravity of situation.
Sources:
There are
numerous sources of noise pollution. In the broad sense, these may be classified
into three categories viz., (i) Industrial machinery noise, (ii) Traffic noise,
and (iii) Community noise.
(i)
Industrial machinery noise:
Major industries run with heavy machineries which produce noise. Persons
working in such industries are constantly exposed to high level of noise.
(ii)
Traffic noise:
In
urban areas, trucks, buses, cars, trains, aeroplanes etc. produce noise at
different levels.
(iii)
Community noise:
The community functions also cause noise pollution. These functions
viz., festivals, marriages, political elections, religious gatherings and so on
are the main causes of community noise. Schools, libraries, study centres and
hospitals are the victims of such noise. The radios, microphones, sound systems
in residential areas also cause noise pollution.
Effects of noise
pollution
The
effects of noise pollution may have differentiated into two categories: auditory effects and non-auditory effects.
1.
Auditory effects:
These
include auditory fatigue and deafness.
(a)
Auditory fatigue:
It
appears at 90 dB and it may be associated with side effects such as whistling
and buzzing to ears.
(b) Deafness:
It is caused due to continuous noise exposure.
Temporary deafness occurs at 400-600 hz. Permanent loss of hearing occurs at
100 dB. Mumbai, Delhi, Kolkata and Chennai are noisy cities in India. Many
persons exposed to unwanted noise have risk of deafness.
2.
Non-auditory effects:
The non-auditory effects are as follows:
(i)
Interference with speech
communication:
A noisy environment that produces more than 50-60 decibel simply does
not allow 2 people to communicate properly. Interpreting the speech of a second
person becomes quite difficult and may lead to misunderstanding.
(ii)
Annoyance:
Some persons
express great annoyance at even low levels of noise as caused by crowed,
highway traffic and radio etc. These cause ill temper, pricking etc.
(iii)
Cardiovascular Issues:
A noisy
environment can be a source of heart related problems. Studies have shown that
high intensity sound causes a dramatic rise in blood pressure as noise levels
constrict the arteries, disrupting the blood ow. The heart rate (the number of
heart-beats per minute) also increases. These sudden abnormal changes in the
blood increase the likelihood of cardiovascular diseases in the long run.
(iv)
Loss of working efficiency:
Because high level noise causes tiredness and those doing mental work
may put to deterioration in their efficiency or even complete loss of ability
to work.
(v)
Physiological disorders:
Noise pollution develops a number of physiological disorders. These are
neurosis, anxiety, insomnia, hypertension, behavioral and emotional stress,
fatigue etc. Thus, noise affects the overall mental and physical health of a
person. Continuous noise causes an increase in cholesterol level which may
cause heart disease. There may be still births and usually low weight children
are born to mothers living near airport. Noise pollution also causes incidence
of peptic ulcers. Supersonic aero planes create shock waves called sonic boon
which produce a starter effect and can be more harmful than a continuous noise.
The sonic boon may spread in the area of 10-80 miles and when it hits the
ground, it damages the window pans and building structures. This may also
fasten the human heart beats.
Control measures of noise pollution
1.
SOURCE CONTROL: This includes source modification such as acoustic
treatment to machine surface, design changes, limiting operational timings, etc
2.
TRANSMISSION PATH INTERVENTION: This
includes containing the source inside a sound insulating enclosure,
constructing a noise barrier or provision of sound absorbing materials along
the path.
3.
RECEPTOR CONTROL: This
includes protection of the receiver by altering the work schedule or provision
of personal protection devices such as ear plugs for operating noisy machinery.
The measure may include dissipation and deflection methods.
4.
OILING: Proper oiling will
reduce noise from the machine.
Preventive measures:
1.
Prescribing noise limits
for vehicular traffic
2.
Ban on honking (usage
of horns) in certain areas
3.
Creation of silence zones
near schools and hospitals
4.
Redesigning buildings to
make them noise proof
5.
Reduction of traffic
density in residential areas
6.
Giving preference to mass
public transport system.
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