pollution and its control
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SubmittedBy :
Mohd. SahilXIIth
Submitted To :Mr. Mohit
Kumar Premi
Subject :Subject :BiologyBiologySession :Session : 2013-142013-14
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DECLARATI!DECLARATI!
T"is is to #o$ gene$%l &ecl%$%tion
'u$'oses only t"%t %ll $ele(%nt )o$*
'e$t%ining to '$esente& +ini%tu$e
'$oject on :,Pollution & its Control,
"%s been solely co+'lete& by +e
Besi&es un%(oi&%ble lin*s to ce$t%in
$e#e$ences. t"e o(e$%ll )o$* is
%bsolutely o$igin%l in n%tu$e
/o"& S%"il/o"& S%"il
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CERTIICATECERTIICATE
T"is is to ce$ti#y t"%t %ll $ele(%nt )o$*
'e$t%ining to '$esente& +ini%tu$e
'$oject on :
"Pollution & its Control")%s co+'lete& by /o"& S%"il un&e$
+y gui&%nce e "%s &one "%$& )o$* to
co+'lete t"e '$oject is )o$* is
%bsolutely o$igin%l in n%tu$e
/$ /o"it u+%$ $e+i/$ /o"it u+%$ $e+i
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BIDATA
Name : Mohd. Sahil
Class / Se : IIt"
Session : 2013-14
Sub!et : Biology
oll No. :
To#i : "Pollution & itsControl"
Sub!et Teaher : /$ /o"it u+%$
$e+i
Teaher$s Si%n :
Prini#al$s Si%n :
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emars :
AC!5LED6E/E!TAC!5LED6E/E!Tisto$y o# %ll g$e%t )o$*s is to )itness t"%t no
g$e%t )o$* )%s e(e$ &one )it"out eit"e$ t"e
%cti(e o$ '%ssi(e su''o$t o# % 'e$son7s
su$$oun&ings %n& one7s close 8u%$te$s T"us it isnot "%$& to conclu&e "o) %cti(e %ssist%nce #$o+
senio$s coul& 'ositi(ely i+'%ct t"e e9ecution o# %
'$oject I %+ "ig"ly t"%n*#ul to ou$ le%$ne&
#%culty /$ /o"it u+%$ $e+i. #o$ "is %cti(e
gui&%nce t"$oug"out t"e co+'letion o# '$oject
L%st but not t"e le%st . I )oul& %lso )%nt to
e9ten& +y %''$eci%tion to +y '%$ents %s )ell %s
t"ose )"o coul& not be +entione& "e$e but "%(e
)ell 'l%ye& t"ei$ $ole to ins'i$e +e be"in& t"e
cu$t%in
/o"& S%"il
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Ancient cultures
Air pollution has always accompanied civilizations. Pollution started
from the prehistoric times when man created the first fires.
According to a 1983 article in the journal Science !soot found onceilings of prehistoric caves provides ample evidence of the high
levels of pollution that was associated with inade"uate ventilation of
open fires.! #he forging of metals appears to $e a %ey turning point
in the creation of significant air pollution levels outside the home.
&ore samples of glaciers in 'reenland indicate increases in pollution
associated with 'ree% (oman and &hinese metal production $ut at
that time the pollution was comparatively less and could $e handled
$y nature.
Official Acknowledgement
)ing *dward + of *ngland $anned the $urning of sea,coal $y
proclamation in -ondon in 1/ after its smo%e $ecame a
pro$lem. 0ut the fuel was so common in *ngland that this earliest of
names for it was ac"uired $ecause it could $e carted away from
some shores $y the wheel$arrow. Air pollution would continue to $e
a pro$lem in *ngland especially later during the industrialrevolution and etending into the recent past with the 'reat Smog
of 192. -ondon also recorded one of the earlier etreme cases of
water "uality pro$lems with the 'reat Stin% on the #hames of 1828
which led to construction of the -ondon sewerage system soon
afterward.
+t was the industrial revolution that gave $irth to environmental
pollution as we %now it today. #he emergence of great factories and
consumption of immense "uantities of coaland other fossilfuels gave rise to unprecedented air pollution and the large volume
of industrial chemical discharges added to the growing load of
untreated human waste.&hicago and &incinnati were the first two
American cities to enact laws ensuring cleaner air in 1881. ther
cities followed around the country until early in the 4th century
when the short lived ffice of Air Pollution was created under the
5epartment of the +nterior. *treme smog events were eperienced
$y the cities of -os Angeles and 5onora Pennsylvania in the late1964s serving as another pu$lic reminder.
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Modern Awareness
Pollution $ecame a popular issue after
7orld 7ar ++ due to radioactive fallout
from atomic warfare and testing. #hen anon,nuclear event #he 'reat Smog of
192 in -ondon %illed at least 6444
people. #his prompted some of the first
major modern environmental legislation
#he &lean Air Act of 192.
Pollution $egan to draw major pu$lic attention in the nited States
$etween the mid,1924s and early 19/4s when &ongress passed
the :oise &ontrol Act the &lean Air Act the &lean 7ater Act and
the :ational *nvironmental Policy Act.
#he major forms of pollution are listed $elow along with the
particular contaminant relevant to each of them;
Air pollution:- the release of chemicals and particulates into
the atmosphere.&ommon gaseous
pollutants include car$on monoide
sulfurdioide chlorofluorocar$ons
and nitrogen oides produced
$y industry and motor vehicles.
Photochemicalozone and smog are
created as nitrogen oides
and hydrocar$ons react to
sunlight. Particulate matter or fine dust is characterized $y
their micrometre size P?14 to P?.2.
Light pollution:-includes light trespass over illumination and
astronomical interference.
Littering:- the criminal throwing of inappropriate man,made
o$jects unremoved onto pu$lic and private properties.
Noise pollution:- which encompasses roadway noise aircraft
noise industrial noise as well as high,intensity sonar.
Soil contaminationoccurs when chemicals are released $y spill
or underground lea%age. Among the most significant soil
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contaminants are hydrocar$ons heavy metals ?#0*
her$icides pesticides and chlorinated hydrocar$ons.
Radioactive contamination resulting from 4th century
activities in atomic physics such as nuclear power generationand nuclear weapons research manufacture and deployment.
Thermal pollution is a temperature change in natural water
$odies caused $y human influence such as use of water as
coolant in a power plant.
isual pollution which can refer to the presence of
overhead power lines motorway $ill$oards scarred
landforms open storage of trashmunicipal solid waste or space de$ris.
!ater pollution $y the discharge of wastewater from
commercial and industrial waste
into surface waters@ discharges of untreated domestic sewage
and chemical contaminants such as chlorine from treated
sewage@ release of waste and contaminants into surface
runoff flowing to surface waters @ waste disposal and leaching
into ground water@ eutrophication and littering.
Sources of air pollution:
#he sources of air pollution can $e natural or man made.
i> :atural Sources
Bolcanic eruptions emitting poisonous gases
5ecay of vegetation
?arsh gases
Pollen grains
=orest fires
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ii> ?an made Sources
+ncrease in pollution
5eforestation
=ossil fuel com$ustion
Behicular emissions
+ndustrialization
se of pesticides insecticides in agriculture
*plosives used in wars
#ypes of Air Pollutants;
#he undesira$le component in the atmosphere causing pollution is
referred to as pollutant. Pollutant can $e classified on the $asis of
origin and physical state. n the $asis of origin pollutants are of
two types;
a> Primary pollutant; it is the product of natural events and human activities added directly to air.*amples include & : S and hydrocar$ons.
$> Secondary pollutant; it is formed $y the interaction of primary
pollutants with each other or with normal components of the
air. *amples include ozone photochemical smog etc.
n the $asis of physical state pollutants are of two types;
i> 'aseous pollutants; these are the gases which mi with the air
without settling down. 'aseous pollutants include & S
& S3 : and hydrocar$ons.
ii> Particulate pollutants; it comprises of finely divided solids or
li"uids. #hese include dust smo%e smog lead mercury
cadmium and as$estos.
Some &ommon Air Pollutants;
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1. &ar$on ?onoide , +t is a colourless odourless tasteless
gas that is $y far the most a$undant of the air pollutants. a
Source, +t is produced due to;
+ncomplete com$ustion of fuels
Automo$ile ehausts
+ndustrial operation
& is also produced through natural processes such as volcanic
activity natural gas and marsh gas emissions.
$. Sin% for & , Sin% is a system which a$sor$s the pollutant
there$y nullifying its harmful effect. A large mass of & isgenerated and also there is continuous increase in & emissions
within recent years. So it is o$vious that the amount of & in the
atmosphere should also increase. 0ut it has $een found that the
amount of & in the atmosphere remains relatively constant
suggesting that a sin% or scavenging process also eists in the
atmosphere. #he micro organisms present in the soil act as a major
sin% for &.A significant amount of & is converted into & $y
these microorganisms.
c. *ffects of & , #he levels of & present in the ur$an air do not
affect significantly the plants and materials. Cowever these levels
adversely affect human health. +n ur$an areas the soil availa$le is
insufficient to act as a sin% there$y increasing the level of &
$eyond permissi$le limits. & interferes with the $loodDs a$ility to
carry oygen to different parts of the $ody. #he oygen com$ines
with hemoglo$in which is also %nown as oygen carrier to form
oyhemoglo$in. #his oyhemoglo$in travels to different parts of the
$ody cells where it gives oygen to the cell and ta%es up &
through the lungs. +f & is inhaled it readily $inds to hemoglo$in to
form car$oyhemoglo$in and $lood carries less oygen to various
parts of the $ody. =ortunately & is removed from the $lood stream
when clear air is cleaned.
d. &ontrol of &, &ontrol of pollution caused $y & can $e
achieved through the following techni"ues;
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?odification of engine design; A low fuel,air ratio reduces :
emissions $ut increase & emissions. So engine design should
design should $e modified so that right proportion of oygen is
maintained for complete oidation of car$on and hydrogen to &
and C4 respectively.
=uel modification; #he fuels which release lesser amount of &
are recommended to $e used. #hese fuels include natural gas
methane and $lends of light hydrocar$ons.
#reatment of ehaust gases; #wo stag catalytic converters are
used to lower the pollution from ehaust gases. +n the first stage
: are reduced to : and :C3 in the presence of catalyst such as
Pt Pd and (uthenium in the presence of reducing gas such as &. in
second stage oidizing catalysts of no$le metals supported on
ceramic materials are used which ensure oidation of & and &.
. ides of :itrogen , A num$er of oides of nitrogen such
as : : : :3 and :2 are introduced into the
atmosphere due to natural as well as human activity. ut of these
the two oides : and : are responsi$le for pollution and are
considered as the pollutants and are represented $y :. : isreddish $rown in color having pungent smell and is suffocating
whereas : is colorless and odorless gas.
a. Source, #he sources of : include;
:atural; during lightening discharge : and in air com$ine
to form :
?an,made sources;
: is formed when : and at very high temperatures. #his
temperature is usually attained during com$ustion of fossil fuel in
air.
: is also produced in chemical industries as $y products
such as in coal $ased power plants sulphuric acid and nitric acid
manufacturing plants
$. Sin% for : , #he : and : undergo various processes inthe atmosphere leading to the formation of C:3. #hus : :
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pollutants gets precipitated as nitrates during rainfall. zone plays a
significant role in these photochemical reactions. +n presence of
volatile organic compounds : reacts with water in presence of
oygen resulting in formation of nitric acid. C:3 comes down from
the atmosphere to the surface of earth in form of acid rain. Cere it
reacts with $ases such as ammonia lime etc. to form nitrates.
c. *ffects , Almost all the : emissions are in the form of :
which has no %nown adverse health effects at the concentrations
found in atmosphere. Cowever : can oidize to : which in
turn may react with hydrocar$ons in the presence of sunlight to
form photochemical smog. #he C:3 formed $y : causes acid
rain which has corroding effect on mar$le and the metallicstructures. +t decreases pC of the soil affecting its fertility.
d. &ontrol of : , #he control measures include;
?odifying the engine design; (educing the amount of ecess
air for com$ustion in air helps in controlling : emissions. #he
$urners are so modified that the fuel and the air mi more slowly
reducing the intensity and temperature of com$ustion.
Scru$$ing the flue gases; #he flue gases are scru$$ed with
CS6 in a scru$$er. #he reaction product thus o$tained is then
decomposed to nitric acid and :.
Selective catalytic reduction; #he selective catalytic reduction
can $e achieved through &C6 :C3 and &. #he : is added to the
ehaust gases and the miture is passed over a fied $ed catalyst
such as copper oide.
+t is interesting to note that the air pollution control methods also
re"uire modification of com$ustion methods. 0ut the methods that
improve & emissions tend to ma%e emissions of : pro$lem
worse and vise versa.
E *nvironmental *ffects of Air Pollution;
#he air pollutants have a great impact on our environment. #hey are
posing a threat to earthDs general environment. #he major effects
are;
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1. Photochemical Smog;
FSmogD is the com$ination of two words Fsmo%eD and FfogD. Smog is of
two types;
-ondon Smog;
#he smog from S particulates and humidity is %nown as -ondon
Smog. #his type of smog caused death of around 6444 people in
-ondon in 192 hence the name. #he miture of smo%e S and
fog is chemically a reducing miture and hence also termed as
reducing smog.
-os Angeles =og ; it results from the
photochemical reactions of the atmosphere. +t is the atmospheric
haze that is formed near many large cities and is due to the action
of sunlight on hydrocar$ons and the nitrogen oides. #his type of
smog was first o$served in -os Angeles in 1924.
. Acid (ain;
npolluted rain water is slightly acidic due to the presence of & in
the atmosphere. & com$ines with the water to form a wea%
solution of car$onic acid with a pC of a$out 2.. Cowever in polluted
environments the rain passes through an atmosphere polluted with
oides of sulphur and nitrogen. #he falling rain reacts with these
oides to form a miture of sulphuric acid and nitric acid and water.
#his is %nown as acid rain. Acid (ain =ormation;
#he oides of sulphur react with moisture to form CS6 in steps;
24 G H S3
243 G C H CS6
Similarly oides of nitrogen form C:3
: G 3 H : G
: G 3 H :3 G
: G :3 H :2
:2 G C H C:3
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#hese acids along with C&- gives rise to the acid rain.
3. 'reen Couse *ffect;
#he green house effect is the rise in temperature that the earth
eperiences $ecause certain gases in the atmosphere a$sor$ energy
from the sun. 7ithout these gases heat would escape $ac% into
space and the earthDs average temperature would $e a$out 4I
colder. #he phenomenon has $een named green house effect as it is
similar to heat trapping effect of the glass walls in a horticulture
green house.
a. #he Process , #he earth receives a tremendous "uantity of
radiant energy from the sun a$out 34J of which is reflected $ac%into space $y the earthDs atmosphere. #he remaining energy passes
through the atmosphere to the earthDs surface. Some of the energy
is a$sor$ed $y plants to drive photosynthesis and some $y the
oceans to evaporate water $ut most is a$sor$ed $y soil roc% and
water to increase the temperature of the earthDs surface. #his
energy is in turn radiated from the heated surface mainly as infrared
radiation often called heat radiation. Cowever only a small portion
of this energy ma%es it $ac% into the space. #he majority of infraredradiations are a$sor$ed the green house gases present in the
atmosphere. A net amount of thermal energy is retained $y the
earth that ma%es it warmer than it would $e without these gases in
the atmosphere.
6. zone -ayer and its 5epletion;
zone is a very small part of our atmosphere $ut its presence is
nevertheless vital to human well$eing. ?ost ozone resides in the
upper part of the atmosphere called stratosphere etending from 1
%m to 64 %m. the high concentration of ozone in the ozone layer
shields us from the harmful ultraviolet light from sun. a *ffect of
zone -ayer , zone protects us from harmful B rays a$sor$ing
these radiations. +n a$sence of ozone layer these rays would reach
earth and cause;
S%in caner
5amage to the plants
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Sun $urns
?elanoma
-eu%emia
&ataracts etc.
#he a$sorption of B radiation $y ozone is a source of heat in
stratosphere. As a result ozone plays a %ey role in maintaining the
temperature structure of earthDs atmosphere.
$. 5epletion of zone , zone depletion has $een found to occur
through the following types of compounds;
&hloroflouro car$ons
:itric oide
(eactive hydroyl radicals
Atomic oygen
c. *ffects of depletion of zone;
#he eisting ozone layer screens out more than 99J of
incoming B radiations. #he small fractions gets through is %nown
to cause sun$urn s%in cancer and various %inds of damage to
animal and plants.
#he genetic material 5:A has the capacity to a$sor$ B
radiations which may cause various disruptive defects.
2J depletion in ozone produces 14J increase in radiations
reaching the earth according to an estimate.
*posure to B radiation damages the cornea and lens of the
eye causing $lindness.
0. 7ater Pollution;
7hen toic su$stances enter la%es streams rivers oceans and
other water $odies they get dissolved or lie suspended in water.
#his results in the pollution of water where $y the "uality of waterdeteriorates. #he word polluted water is defined as the deterioration
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of physical chemical and $iological properties of water $rought
mainly $y human activities and natural resources and which cause
harmful effect on human and a"uatic life.
E Sources of water pollution , 7ater pollution is caused $yhuman as well as natural activities.
i> :atural Sources , #hese include decomposed vegeta$le
animal and weathered products which are $rought into main water
resources.
ii> Cuman Activities , #hese include domestic as well as industrial
pollution;
a. 5omestic; #he release of huge "uantities of municipal and
domestic wastes through the drains into the rivers and canals is the
major cause of pollution. #he domestic waste water contains human
faeces %itchen wastes organic water that provides nutrition to
fungi and $acteria.
$. +ndustrial; #hese include effluents from factories refineries
and a num$er of chemical industries. 7ater gets polluted $y acids
al%alis detergents copper zinc lead mercury etc. which areconstantly added to water $y industrial effluents.
c. Apart from these two the water is also polluted through
agricultural discharge such as pesticides insecticides fertilizers etc.
$esides these $acteria algae virus also cause water pollution.
E &lassification of 7ater Pollutants;
#he pro$lem of water pollution due to discharge of domestic and
industrial waste into water has already $ecome a serious pro$lem in
the country. #o aid in the systematic discussion of water pollutants
they have $een classified into nine categories;
1. ygen demanding wastes
. Pathogens
3. Synthetic organic compounds
6. Plant nutrients
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2. +norganic chemicals and minerals
. Sediments
/. (adioactive su$stances
8. #hermal discharges
9. il
1. ygen 5emanding 7astes;
5issolved oygen is essential for sustaining the plant and
animal life in any a"uatic system. 7arm,water fishes re"uire a
minimum 5 level of 2 mgK-. if 5 level drops $elow the levelnecessary to sustain normal life then water is classified as polluted.
#he amount of 5 in water is reduced $ecause of oygen
demanding wastes. #hese are su$stances that oidize in water
reducing the amount of 5. #hese include organic su$stances
contained in municipal waste water or in effluents from certain
industries. #he oygen demanding wastes are oidized $y $acteria
or micro organisms consuming 5 in water to & and water. #hese
su$stances produce undesira$le odor tastes and reduce the
accepta$ility of water as domestic supply.
#here are several measures f oygen demand commonly used;
0iological ygen 5emand ; 05 is the amount of
oygen re"uired $y microorganisms to $iologically degrade the
wastes. +t is the most important measure of the strength of organic
pollution
&hemical ygen 5emand ; &5 is the amount ofoygen needed to chemically oidize the wastes.
1. Pathogens , #hese are disease causing organisms that grow
and multiply within the host. 7ater is potential carrier of pathogenic
microorganisms. #hese pathogens are carried into the water $odies
$y sewage and wastes from farm and various industries.
&ontaminated water caused $y poor sanitation can lead to $oth
water $orne and water contact diseases. 7ater $orne diseases are
those ac"uired $y ingestion of pathogens not only in drin%ing water
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$ut also from the water that ma%es it to personDs mouth from
washing food utensils and hands. *amples are cholera typhoid
etc. 7ater &ontact diseases do not re"uire that the individual ingest
the water. Lust contact with the water causes the disease. =or
eample $ilharzia is the most common water contact disease in the
world.
. Synthetic rganic &ompounds , #hese include pesticides
synthetic organic chemicals and detergents. #hese compounds are
not $iodegrada$le and persist for longer periods. ?ost of these are
accumulative toic poisons and ultimately reach o$jectiona$le levels
in water. Pesticides cover a range of chemicals that %ill organisms
that human consider undesira$le. #hese enter the water $odies fromrun off from agricultural lands waste discharge $y pesticides
manufacturers and $y other means. 0ecause of their world wide
usage nearly all the rivers and oceans of the world contain
pesticides residue. 5etergent means cleansing agent. #he $asic
active ingredient in detergents is surfactant or surface active agent
with contains hydropho$ic and hydrophilic groups. Surfactants
decrease the surface tension of water so that they can penetrate the
surface and interstices of the o$ject to $e cleaned. #e remainder
comprises of polysulphate salts called $uilders and other
ingredients. Surfactants concentrations as low as 1ppm produce
foam in rivers and in sewage treatment plants. Although these
concentrations are non,toic to humans their presence gives off
taste of drin%ing water. #he detergent $uilders pose greater pro$lem
today. #he polyphosphates $uilders are released into water and act
as plant nutrients. #he etensive growth of algae consumes most of
dissolved oygen from water.
3. Plant nutrients , :utrients are chemicals such as nitrogen
phosphorus car$on sulphur calcium potassium iron etc. that are
essential to growth of living things. Cowever in terms of water
these nutrients are considered as pollutants@ when their
concentrations are sufficient allow ecessive growth of a"uatic
plants particularly algae. 7hen these algae die and decompose
they add undesira$le odor and o$jectiona$le taste of water. =urther
the decaying of organic matter oidizes and leads to reduced 5
levels. #he gradual accumulation of silt and organic matter is %nown
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as eutrophication. Cigh concentration of nutrients poses the pro$lem
of eutrophication $ut also when found in drin%ing water it is a
serious health hazard.
6. +norganic &hemicals and ?inerals , #his include inorganic saltsmineral acids and finely divided metal or metal compounds trace
elements cyanides organo,metallic compounds etc. they are added
to the water $odies through municipal and industrial waste water
and mine run off.
a. Acid ?ine 5rainage , +t is a source of increasing acidity in
natural water acid rain also adds to it. #he mining of sulphur
$earing ores containing lead zinc and copper lead to acid drainage.
&oal mines discharge is also a cause of acid mine drainage.
$. Solu$le Salts , #he salts or solids passing through water on its
way to sea include cations such as sodium calcium potassium
magnesium and anions li%e chlorides sulphates and $icar$onates.
#he measure of salinity is concentration of total dissolved solids
.
c. Ceavy ?etals , +t refers to metals with specific gravity greater
than 6 or 2. ?etals may $e inhaled or digested and have adverse
effects on the $ody. &admium lead and mercury are nephrotoic
metals.
2. Sediments , #hey include soil sand and mineral particles
washed into a"uatic environment $y storms and flood waters. #hey
are sources of organic and inorganic matter which reduces the
storage capacity. #his decreases evolution of oygen and hence
cannot support a"uatic animals.
. (adioactive Su$stances , #hey enter a"uatic system through
the use of naturally occurring or artificially produced radioactive
materials. #hese pollutants enter the water system through;
?ining and processing of ores
:uclear power plants
-ea%age from underground nuclear detonations
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(adioisotopes in medicine etc.
/. #hese su$stances can enter human $ody through food and
water and cause cancer eye cataract etc.
a. #hermal 5ischarges;
#he used coolant water in industries id directly discharged into
water $odies which increases their temperature. #his is thermal
pollution. (ise in temperature decreases 5 content which affects
the a"uatic life.
$. il;
+t is added to water $odies from industries as effluents oil refineriesstorage tan%s and automo$ile waste oil. il $eing insolu$le in water
floats over it. +t may penetrate the feathers of $irds such that they
find difficulty in floating and flying. #hey may ingest it and die.
c. Bolatile rganic &ompounds;
#hey are volatile solvents used in industries. #hey are toic and
cause harm when present in drin%ing water. Some of the B&s are;
Binyl chloride
# etrachloroethylene
&ar$ontetrachloride
#richloroethylene
7aste 7ater treatment Process; Availa$le waste water
treatment processes can $e classified as;
Physical
&hemical
0iological
#he waste water treatment processes are generally grouped
according to water "uality they are epected to produce
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1. Primary #reatment , +t utilizes physical processes li%e
screening to remove a portion of pollutants that settle or float.
Pretreatment; +t consists of screening and grit removal.
Screening removes large floating o$jects which are disposed off.#hen water passes into grit cham$er where velocity of water is
reduced.
Sedimentation; =rom grit cham$er sewage passes into
primary settling tan% called sedimentation $asin. +t clarifies
suspended solids and 64J of organic matter.
. Secondary #reatment , #he purpose here is to remove organic
matter and is $ased upon $iological process similar to natural$iodegradation $y aero$ic $acteria. #hey include;
&oagulation of colloidal matter
idation of organic matter
&onversion of nitrogeneous matter to ammonia and finally to
nitrites and nitrates
Anaero$ic digestion of sludge
3. #ertiary #reatment , +t improves the "uality of effluent further.
+t includes removal of;
Suspendedsolids
0acteria
5issolved organic solids
#oics
:utrients
Some of the techni"ues are;
?icro,staining; +t removes the solid wastes that get retained
on fa$ric of filter media
(emoval of 5issolved Solids; +t can $e done $y adsorption ofsolu$le organics on activated car$on solvent etraction ion,
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echange reverse osmosis and
chemical precipitation through lime etc.
(emoval of :utrients; it includes removal of nitrogen
and phosphorous which may $e present asorthophosphates $y alum.
(emoval of $acteria; 0y retaining effluents in maturation
pond for specified period of times.
&. Soil Pollution;
E Sources; Soil pollution is degradation of soil mainly through
human misuse. #he human influences include;
+ndustrial waste; this is disposed into the soil and poses a
detrimental effect.
5isposal of solid wastes; this is accumulation of lead
particles from automo$ile ehausts gar$age containing
plastics etc.
Agricultural practices; this is due to fertilizers and use of
pesticides.
0iological agents; this is through ecreta of humans $irds
and animals.
Soil erosion; nutrients for supporting vegetation are wiped
off.
E *ffects; Soil pollution adds a num$er of chemicals to it and
these are transferred into humans through food chains.
?etallic contaminants destroy the $eneficial micro organisms
in soil and hence effect plant growth. *cessive use of
fertilizers ma%es soil al%aline or acidic. se of pesticides ma%es
soil contaminated and is also persistent. #he most dangerous
pesticide 55# is now $anned as it accumulates in the food
chain.
E &ontrol; #hey include method to reduce and dispose soil
wastes. #his can $e achieved through following ways,
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Proper dumping of soil wastes
0anning of highly toic and persistent chemical pesticides
Proper awareness of the masses
+ncreased crop rotation
(ecycling of the waste
Plantation of trees to a larger etent.
"uman health
verview of main health effects on humans from some common
types of pollution.
Adverse air "uality can %ill many organisms including humans.
zone pollution can cause respiratory disease cardiovascular
disease throat inflammation chest pain and congestion. 7aterpollution causes approimately 16444 deaths per day mostly due
to contamination of drin%ing water $y untreated sewage in
developing countries. An estimated 244 million +ndians have no
access to a proper toilet and 284 +ndians die of water,related
pollution every day. :early 244 million &hinese lac% access to safe
drin%ing water. A 414 analysis estimated that 1. million people
died prematurely in a year in &hina $ecause of air pollution. +n 44/
it was estimated that in +ndia air pollution is $elieved to cause
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2//44 fatalities. Studies have estimated that the num$er of
people %illed annually in the S could $e over 24444.
il spills can cause s%in irritations and rashes. :oise pollution
induces hearing loss high $lood pressure stress and sleepdistur$ance. ?ercury has $een lin%ed to developmental deficits in
children and neurological symptoms. lder people are majorly
eposed to diseases induced $y air pollution. #hose with heart or
lung disorders are at additional ris%. &hildren and infants are also at
serious ris%. -ead and other heavy metals have $een shown to
cause neurological pro$lems. &hemical and radioactive su$stances
can cause cancerand as well as $irth defects.
#erspectives
#he earliest precursor of pollution generated $y life forms would
have $een a natural function of their eistence. #he attendant
conse"uences on via$ility and population levels fell within the
sphere of natural selection. #hese would have included the demise
of a population locally or ultimately species etinction. Processes
that were untena$le would have resulted in a new $alance $rought
a$out $y changes and adaptations. At the etremes for any form of
life consideration of pollution is superseded $y that of survival.
=or human%ind the factor of technology is a distinguishing and
critical consideration $oth as an ena$ler and an additional source of
$yproducts. Short of survival human concerns include the range
from "uality of life to health hazards. Since science holds
eperimental demonstration to $e definitive modern treatment of
toicity or environmental harm involves defining a level at which aneffect is o$serva$le. &ommon eamples of fields where practical
measurement is crucial include automo$ile emissions control
industrial eposure .#he solution to pollution is dilution! is a dictum
which summarizes a traditional approach to pollution management
where$y sufficiently diluted pollution is not harmful. +t is well,suited
to some other modern locally scoped applications such as
la$oratory safety procedure and hazardous material release
emergency management. 0ut it assumes that the dilutant is in
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virtually unlimited supply for the application or that resulting
dilutions are accepta$le in all cases.
Such simple treatment for environmental pollution on a wider scale
might have had greater merit in earlier centuries when physicalsurvival was often the highest imperative human population and
densities were lower technologies were simpler and their
$yproducts more $enign. 0ut these are often no longer the case.
=urthermore advances have ena$led measurement of
concentrations not possi$le $efore. #he use of statistical methods in
evaluating outcomes has given currency to the principle of pro$a$le
harm in cases where assessment is warranted $ut resorting to
deterministic models is impractical or infeasi$le. +n additionconsideration of the environment $eyond direct impact on human
$eings has gained prominence.
Met in the a$sence of a superseding principle this older approach
predominates practices throughout the world. +t is the $asis $y
which to gauge concentrations of effluent for legal release
eceeding which penalties are assessed or restrictions applied. ne
such superseding principle is contained in modern hazardous waste
laws in developed countries as the process of diluting hazardouswaste to ma%e it non,hazardous is usually a regulated treatment
process. ?igration from pollution dilution to elimination in many
cases can $e confronted $y challenging economical and
technological $arriers.
$reenhouse gases and glo%al warming
&ar$on dioide while vital for photosynthesis is sometimes referred
to as pollution $ecause raised levels of the gas in the atmosphereare affecting the *arthNs climate. 5isruption of the environment can
also highlight the connection $etween areas of pollution that would
normally $e classified separately such as those of water and air.
(ecent studies have investigated the potential for long,term rising
levels of atmospheric car$on dioide to cause slight $ut
critical increases in the acidity of ocean waters and the possi$le
effects of this on marine ecosystems.
Most polluted places in the developing world
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#he 0lac%smith +nstitute an international non,for,profit organization
dedicated to eliminating life,threatening pollution in the developing
world issues an annual list of some of the worldNs worst polluted
places. +n the 44/ issues the ten top nominees already
industrialized countries ecluded are located
in Azer$aijan &hina +ndia Peru (ussia%raine and Oam$ia.
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