Environmental Pollution.pdf

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1. Environmental Pollution
AECC-I
Unit 1

2. Environmental Pollution
Theenvironmentisdefinedasthesurroundingsofa
physicalsystemthatmayinteractwithothersystems
byexchangingmassandenergy.Allthelivingbeings
andthenon-livingthingsfallundernatural
environment.Theenvironmentisthesurrounding
thatwelivein,andsoitisourresponsibilityto
protectitfromanydestruction.Environmental
pollutionisoneofthegreatestproblemsthathuman
societyisfacingtoday.Air,water,andsoilformthe
threebasicareasofenvironmentalpollution.

3. Whenthereisanundesirablechangeinthe
surroundingthathasharmfuleffectsonplantsand
animals,itleadstoenvironmentalpollution.Apollutantis
asubstancethatcausespollution.Wecanhavepollutants
inliquid,solidorgaseousform.Asubstancebecomesa
pollutantwhenitsconcentrationisgreaterthanthe
naturalabundanceandthisincreaseinconcentrationis
eitherduetohumanactivitiesornaturalphenomenon.
Therearepollutantswhichcanbedegradedandrapidly
brokendownbynaturalprocessessimilartothe
degradationofvegetables.Wealsohavepollutantswhich
takedecadestodegrade,oncereleasedcannotbeeasily
removed.Forexample,DDT,plasticmaterials,heavy
metalsandnuclearwaste.

4. EffectsofEnvironmentalPollution:
Ithasbeenseenthatpollutantsoriginateatapointandarethen
transportedtootherplacesbytheactionofwindorwater.Some
pollutantsaredumpedintothesoilbyhumanbeings.Thisleadstoair,
waterandsoilpollutionrespectively.Ifthesoilispolluted,theuseful
microorganismsinitwilldieandthefertilityofsoilwillbelost.The
productionofcropswilldecrease.Ifthesoilisnotfertile;itwillhavea
harmfulimpactonthehumansociety.Similarly,ifwaterispolluted
thenwehavetopurifyitbeforedrinking.Purificationneedsresources.
Lastly,ifairispolluted,respirationwillbecomeanissueandsurvivalof
lifewillbeunderthreat.Airpollutionleadstomanyrespiratory
diseasesandharmsthehumanbody.
Wecanconcludebysayingthatenvironmentalpollutionwill
affectthelifeonearthandshouldbereducedasfaraspossible.We
harmthenatureandinturn,naturewillharmusmore.Thisshouldbe
stopped,oursurvivaldependsonthisenvironmentsocareshouldbe
takenanditsbalanceshouldbemaintained.

5. SourcesofPollution:
Environmentalpollutionismostlyduetodirector
indirecthumanactivities,arisingoutofthebuilt-world
createdbyhumans.
Therearesixmajorsourcesofenvironmentalpollution:
1.Industrialsources
2.Agriculturalsources
3.Biogenicsources
4.Anthropogenicsources
5.Unnaturalsources
6.Extra-terrestrialsources.

6. Therelativeimportanceofeachoneofthesesources
dependsonthesite-specificsituation.Forinstanceincities,
anthropogenicsourcesarethemajorcontributorswhileinrural
areas,agriculturalsourcessignificantlyaddtopollution.
TypesofPollution:
Theenvironmentalpollutionmaybecategorizedintosixmajor
groups:
1.Air/atmospherepollution
2.Waterpollution
3.Land/soilpollution
4.Noisepollution
5.Thermalpollution
6.Radioactivepollution.

7. NatureofPollutants:
Thepollutantsthatoccurintheenvironmentmaybe
chemical,biologicalandphysicalintheirnature.
Chemicalpollutants:
Gaseouspollutants(sulfurdioxide,nitrogendioxide),toxic
metals,pesticides,herbicides,hydrocarbons,toxins,acidic
substances,carcinogens.
Biologicalpollutants:
Pathogenicorganisms,productsofbiologicalorigin.
Physicalpollutants:
Heat(thermal),sound,odours,radiationandradioactive
substances.

8. WhatisAirPollution?
Airpollutionreferstoanyphysical,chemicalor
biologicalchangeintheair.Itisthecontaminationof
airbyharmfulgases,dustandsmokewhichaffects
plants,animalsandhumansdrastically.
Thereisacertainpercentageofgasespresentin
theatmosphere.Anincreaseordecreaseinthe
compositionofthesegasesisharmfultosurvival.This
imbalanceinthegaseouscompositionhasresultedin
anincreaseinearth’stemperature,whichisknownas
globalwarming.

9. TypesofAirPollutants
Therearetwotypesofairpollutants:
PrimaryPollutants
Thepollutantsthatdirectlycauseairpollution
areknownasprimarypollutants.Sulphur-dioxide
emittedfromfactoriesisaprimarypollutant.
SecondaryPollutants
Thepollutantsformedbytheinterminglingand
reactionofprimarypollutantsareknownas
secondarypollutants.Smog,formedbythe
interminglingofsmokeandfog,isasecondary
pollutant.

10. CausesofAirPollution
Followingaretheimportantcausesofairpollution:
BurningofFossilFuels
Thecombustionoffossilfuelsemitsalargeamountofsulphurdioxide.
Carbonmonoxidereleasedbyincompletecombustionoffossilfuels
alsoresultsinairpollution.
Automobiles
Thegasesemittedfromvehiclessuchasjeeps,trucks,cars,buses,etc.
pollutetheenvironment.Thesearethemajorsourcesofgreenhouse
gasesandalsoresultindiseasesamongindividuals.
AgriculturalActivities
Ammoniaisoneofthemosthazardousgasesemittedduring
agriculturalactivities.Theinsecticides,pesticidesandfertilizersemit
harmfulchemicalsintheatmosphereandcontaminateit.

11. FactoriesandIndustries
Factoriesandindustriesarethemainsourceofcarbon
monoxide,organiccompounds,hydrocarbonsandchemicals.
Thesearereleasedintotheair,degradingitsquality.
MiningActivities
Intheminingprocess,themineralsbelowtheearthare
extractedusinglargepiecesofequipment.Thedustand
chemicalsreleasedduringtheprocessnotonlypollutetheair,
butalsodeterioratethehealthoftheworkersandpeopleliving
inthenearbyareas.
DomesticSources
Thehouseholdcleaningproductsandpaintscontaintoxic
chemicalsthatarereleasedintheair.Thesmellfromthenewly
paintedwallsisthesmellofthechemicalspresentinthepaints.
Itnotonlypollutestheairbutalsoaffectsbreathing.

12. EffectsofAirPollution
Thehazardouseffectsofairpollutionontheenvironmentinclude:
Diseases
Airpollutionhasresultedinseveralrespiratorydisordersand
heartdiseasesamonghumans.Thecasesoflungcancerhaveincreased
inthelastfewdecades.Childrenlivingnearpollutedareasaremore
pronetopneumoniaandasthma.Manypeopledieeveryyeardueto
thedirectorindirecteffectsofairpollution.
GlobalWarming
Duetotheemissionofgreenhousegases,thereisanimbalance
inthegaseouscompositionoftheair.Thishasledtoanincreaseinthe
temperatureoftheearth.Thisincreaseinearth’stemperatureis
knownasglobalwarming.Thishasresultedinthemeltingofglaciers
andanincreaseinsealevels.Manyareasaresubmergedunderwater.

13. AcidRain
Theburningoffossilfuelsreleasesharmfulgasessuchas
nitrogenoxidesandsulphuroxidesintheair.Thewaterdroplets
combinewiththesepollutants,becomeacidicandfallasacidrain
whichdamageshuman,animalandplantlife.
OzoneLayerDepletion
Thereleaseofchlorofluorocarbons,halons,andhydro
chlorofluorocarbonsintheatmosphereisthemajorcauseofdepletion
oftheozonelayer.Thedepletingozonelayerdoesnotpreventthe
harmfulultravioletrayscomingfromthesunandcausesskindiseases
andeyeproblemsamongindividuals.
EffectonAnimals
Theairpollutantssuspendonthewaterbodiesandaffectthe
aquaticlife.Pollutionalsocompelstheanimalstoleavetheirhabitat
andshifttoanewplace.Thisrendersthemstrayandhasalsoledto
theextinctionofalargenumberofanimalspecies.

14. AirPollutionControl
Followingarethemeasuresoneshouldadopt,tocontrolairpollution:
AvoidUsingVehicles
Peopleshouldavoidusingvehiclesforshorterdistances.Rather,they
shouldpreferpublicmodesoftransporttotravelfromoneplaceto
another.Thisnotonlypreventspollution,butalsoconservesenergy.
EnergyConservation
Alargenumberoffossilfuelsareburnttogenerateelectricity.
Therefore,donotforgettoswitchofftheelectricalapplianceswhen
notinuse.Thus,youcansavetheenvironmentattheindividuallevel.
Useofenergy-efficientdevicessuchCFLsalsocontrolspollutiontoa
greaterlevel.
UseofCleanEnergyResources
Theuseofsolar,windandgeothermalenergiesreduceairpollutionat
alargerlevel.Variouscountries,includingIndia,haveimplementedthe
useoftheseresourcesasasteptowardsacleanerenvironment.

15. Otherairpollutioncontrolmeasuresinclude:
1.Byminimizingandreducingtheuseoffireandfireproducts.
2.Sinceindustrialemissionsareoneofthemajorcausesofairpollution,thepollutantscan
becontrolledortreatedatthesourceitselftoreduceitseffects.Forexample,ifthe
reactionsofacertainrawmaterialyieldapollutant,thentherawmaterialscanbe
substitutedwithotherlesspollutingmaterials.
3.Fuelsubstitutionisanotherwayofcontrollingairpollution.InmanypartsofIndia,petrol
anddieselarebeingreplacedbyCNG–CompressedNaturalGasfueledvehicles.These
aremostlyadoptedbyvehiclesthataren’tfullyoperatingwithidealemissionengines.
4.AlthoughtherearemanypracticesinIndia,whichfocusonrepairingthequalityofair,
mostofthemareeitherforgottenornotbeingenforcedproperly.Therearestillalotof
vehiclesonroadswhichhaven’tbeentestedforvehicleemissions.
5.Anotherwayofcontrollingairpollutioncausedbyindustriesistomodifyandmaintain
existingpiecesofequipmentsothattheemissionofpollutantsisminimized.
6.Sometimescontrollingpollutantsatthesourceisnotpossible.Inthatcase,wecanhave
processcontrolequipmenttocontrolthepollution.
7.Averyeffectivewayofcontrollingairpollutionisbydilutingtheairpollutants.
8.Thelastandthebestwayofreducingtheilleffectsofairpollutionistreeplantation.
Plantsandtreesreducealargenumberofpollutantsintheair.Ideally,plantingtreesin
areasofhighpollutionlevelswillbeextremelyeffective.

16. Waterisoneofthemostvitalnaturalresourceson
earthandhasbeenaroundforalongtime.Infact,the
samewaterwhichwedrinkhasbeenaroundinoneform
ortheothersincethetimeofthedinosaurs.
Theearthhasmorethantwo-thirdsofitssurface
coveredwithwater.Thistranslatestojustover1octillion
litres(1,260,000,000,000,000,000,000litres)ofwater
distributedintheoceans,rivers,lakesandstreams.
However,lessthan0.3%isaccessibleforhuman
consumption.Ascommercializationandindustrialization
haveprogressed,thatnumbercontinuestodwindledown.
Furthermore,inefficientandoutdatedpractices,lackof
awarenessandaplethoraofothercircumstanceshaveled
towaterpollution.

17. WhatisWaterPollution?
Waterpollutioncanbedefinedasthe
contaminationofwaterbodies.Waterpollutionis
causedwhenwaterbodiessuchasrivers,lakes,
oceans,groundwaterandaquifersget
contaminatedwithindustrialandagricultural
effluents.
Whenwatergetspolluted,itadversely
affectsalllifeformsthatdirectlyorindirectly
dependonthissource.Theeffectsofwater
contaminationcanbefeltforyearstocome.

18. SourcesOfWaterPollution
ThekeycausativesofwaterpollutioninIndiaare:
1.Urbanization.
2.Deforestation.
3.Industrialeffluents.
4.SocialandReligiousPractices.
5.UseofDetergentsandFertilizers.
6.Agriculturalrun-offs-Useofinsecticidesand
pesticides.

20. Oneoftheprimarycausesofwaterpollutionisthe
contaminationofwaterbodiesbytoxicchemicals.Asseenin
theexamplementionedabove,thedumpedplasticbottles,
tins,watercansandotherwastespollutethewaterbodies.
Theseresultinwaterpollution,whichharmsnotjusthumans,
butthewholeecosystem.Toxinsdrainedfromthese
pollutants,traveluptothefoodchainandeventuallyaffect
humans.Inmostcases,theoutcomeisdestructivetoonly
localpopulationandspecies,butitcanhaveanimpactona
globalscaletoo.
Nearly6billionkilogramsofgarbageisdumpedevery
yearintheoceans.Apartfromindustrialeffluentsand
untreatedsewage,otherformsofunwantedmaterialsare
dumpedintovariouswaterbodies.Thesecanrangefrom
nuclearwastetooilspills–thelatterofwhichcanrendervast
areasuninhabitable.

21. EffectsOfWaterPollution
Theeffectofwaterpollutiondependsuponthetypeofpollutantsandits
concentration.Also,thelocationofwaterbodiesisanimportantfactortodeterminethe
levelsofpollution.
1.Waterbodiesinthevicinityofurbanareasareextremelypolluted.Thisistheresultof
dumpinggarbageandtoxicchemicalsbyindustrialandcommercialestablishments.
2.Waterpollutiondrasticallyaffectsaquaticlife.Itaffectstheirmetabolism,behaviour,
causesillnessandeventualdeath.Dioxinisachemicalthatcausesalotofproblems
fromreproductiontouncontrolledcellgrowthorcancer.Thischemicalis
bioaccumulatedinfish,chickenandmeat.Chemicalssuchasthistravelupthefood
chainbeforeenteringthehumanbody.
3.Theeffectofwaterpollutioncanhaveahugeimpactonthefoodchain.Itdisruptsthe
food-chain.Cadmiumandleadaresometoxicsubstances,thesepollutantsupon
enteringthefoodchainthroughanimals(fishwhenconsumedbyanimals,humans)
cancontinuetodisruptathigherlevels.
4.Humansareaffectedbypollutionandcancontractdiseasessuchashepatitisthrough
faecalmatterinwatersources.Poordrinkingwatertreatmentandunfitwatercan
alwayscauseanoutbreakofinfectiousdiseasessuchascholera,etc.
5.Theecosystemcanbecriticallyaffected,modifiedanddestructuredbecauseofwater
pollution.

22. ControlMeasuresofWaterPollution
Waterpollution,toalargerextent,canbecontrolledbyavariety
ofmethods.Ratherthanreleasingsewagewasteintowaterbodies,itis
bettertotreatthembeforedischarge.Practisingthiscanreducethe
initialtoxicityandtheremainingsubstancescanbedegradedand
renderedharmlessbythewaterbodyitself.Ifthesecondarytreatment
ofwaterhasbeencarriedout,thenthiscanbereusedinsanitary
systemsandagriculturalfields.
Averyspecialplant,theWaterHyacinthcanabsorbdissolved
toxicchemicalssuchascadmiumandothersuchelements.Establishing
theseinregionspronetosuchkindsofpollutantswillreducethe
adverseeffectstoalargeextent.
Somechemicalmethodsthathelpinthecontrolofwater
pollutionareprecipitation,theionexchangeprocess,reverseosmosis,
andcoagulation.Asanindividual,reusing,reducing,andrecycling
whereverpossiblewilladvancealongwayinovercomingtheeffectsof
waterpollution.

23. WhatisSoilPollution?
Soilpollutionreferstothecontaminationof
soilwithanomalousconcentrationsoftoxic
substances.Itisaseriousenvironmentalconcern
sinceitharboursmanyhealthhazards.For
example,exposuretosoilcontaininghigh
concentrationsofbenzeneincreasestheriskof
contractingleukaemia.

24. Itisimportanttounderstandthatallsoils
containcompoundsthatareharmful/toxicto
humanbeingsandotherlivingorganisms.
However,theconcentrationofsuchsubstancesin
unpollutedsoilislowenoughthattheydonot
poseanythreattothesurroundingecosystem.
Whentheconcentrationofoneormoresuch
toxicsubstancesishighenoughtocausedamage
tolivingorganisms,thesoilissaidtobe
contaminated.

25. Therootcauseofsoilpollutionisoftenoneofthe
following:
•Agriculture(excessive/improperuseofpesticides)
•Excessiveindustrialactivity
•Poormanagementorinefficientdisposalofwaste
Thechallengesfacedinsoilremediation
(decontaminationofsoil)arecloselyrelatedtothe
extentofsoilpollution.Thegreaterthe
contamination,thegreatertherequirementof
resourcesforremediation.

26. WhatarethePollutantsthatContaminateSoil?
Someofthemosthazardoussoilpollutantsarexenobiotics
–substancesthatarenotnaturallyfoundinnatureandare
synthesizedbyhumanbeings.Theterm‘xenobiotic’has
Greekroots–‘Xenos’(foreigner),and‘Bios’(life).Several
xenobioticsareknowntobecarcinogens.Anillustration
detailingmajorsoilpollutantsisprovidedbelow.
Thedifferenttypesofpollutantsthatarefoundin
contaminatedsoilarelistedinthissubsection.
HeavyMetals
Thepresenceofheavymetals(suchasleadandmercury,
inabnormallyhighconcentrations)insoilscancauseitto
becomehighlytoxictohumanbeings.Somemetalsthat
canbeclassifiedassoilpollutantsaretabulatedbelow.

28. Thesemetalscanoriginatefromseveralsourcessuchasmining
activities,agriculturalactivities,electronicwaste(e-waste),andmedical
waste.
PolycyclicAromaticHydrocarbons
Polycyclicaromatichydrocarbons(oftenabbreviatedtoPAHs)are
organiccompoundsthat:
1.Containonlycarbonandhydrogenatoms.
2.Containmorethanonearomaticringintheirchemicalstructures.
CommonexamplesofPAHsincludenaphthalene,anthracene,
andphenalene.Exposuretopolycyclicaromatichydrocarbonshasbeen
linkedtoseveralformsofcancer.Theseorganiccompoundscanalso
causecardiovasculardiseasesinhumans.
SoilpollutionduetoPAHscanbesourcedtocoke(coal)
processing,vehicleemissions,cigarettesmoke,andtheextractionof
shaleoil.

29. IndustrialWaste
Thedischargeofindustrialwasteintosoilscanresultinsoilpollution.Somecommonsoil
pollutantsthatcanbesourcedtoindustrialwastearelistedbelow.
•Chlorinatedindustrialsolvents
•Dioxinsproducedfromthemanufactureofpesticidesandtheincinerationofwaste.
•Plasticizers/dispersants
•Polychlorinatedbiphenyls(PCBs)
Thepetroleumindustrycreatesmanypetroleumhydrocarbonwasteproducts.
Someofthesewastes,suchasbenzeneandmethylbenzene,areknowntobecarcinogenic
innature.
Pesticides
Pesticidesaresubstances(ormixturesofsubstances)thatareusedtokillorinhibitthe
growthofpests.Commontypesofpesticidesusedinagricultureinclude:
•Herbicides–usedtokill/controlweedsandotherunwantedplants.
•Insecticides–usedtokillinsects.
•Fungicides–usedtokillparasiticfungiorinhibittheirgrowth.

30. WhataretheProcessesthatCauseSoilPollution?
Soilpollutioncanbebroadlyclassifiedintotwocategories–
•Naturallycausedsoilpollution
•Anthropogenicsoilpollution(causedbyhumanactivity)
NaturalPollutionofSoil
Insomeextremelyrareprocesses,somepollutantsarenaturally
accumulatedinsoils.Thiscanoccurduetothedifferentialdeposition
ofsoilbytheatmosphere.Anothermannerinwhichthistypeofsoil
pollutioncanoccurisviathetransportationofsoilpollutantswith
precipitationwater.
Anexampleofnaturalsoilpollutionistheaccumulationof
compoundscontainingtheperchlorateanion(ClO4–)insomedry,arid
ecosystems.Itisimportanttonotethatsomecontaminantscanbe
naturallyproducedinthesoilundertheeffectofcertainenvironmental
conditions.Forexample,perchloratescanbeformedinsoilscontaining
chlorineandcertainmetalsduringathunderstorm.

31. AnthropogenicSoilPollution
Almostallcasesofsoilpollutionareanthropogenicinnature.Avarietyofhumanactivitiescan
leadtothecontaminationofsoil.Somesuchprocessesarelistedbelow.
•Thedemolitionofoldbuildingscaninvolvethecontaminationofnearbysoilwithasbestos.
•Usageoflead-basedpaintduringconstructionactivitiescanalsopollutethesoilwithhazardous
concentrationsoflead.
•Spillageofpetrolanddieselduringtransportationcancontaminatesoilswiththehydrocarbonsfound
inpetroleum.
•Activitiesassociatedwithmetalcastingfactories(foundries)oftencausethedispersionofmetallic
contaminantsintothenearbysoils.
•Undergroundminingactivitiescancausethecontaminationoflandwithheavymetals.
•Improperdisposalofhighlytoxicindustrial/chemicalwastecanseverelypollutethesoil.Forexample,
thestorageoftoxicwastesinlandfillscanresultintheseepageofthewasteintothesoil.Thiswaste
cangoontopollutegroundwateraswell.
•Chemicalpesticidescontainseveralhazardoussubstances.Excessiveandinefficientuseofchemical
pesticidescanresultinseveresoilpollution.
•Sewageproducedinurbanizedareascanalsocontaminatesoil(ifnotdisposedofcorrectly).These
wastesmayalsocontainseveralcarcinogenicsubstances.
Otherformsofwastethatcanpollutesoilincludenuclearwaste,e-waste,andcoalash.

32. WhataretheNegativeConsequencesofSoilPollution?
Soilpollutionharboursabroadspectrumofnegativeconsequencesthat
affectplants,animals,humans,andtheecosystemasawhole.Sincechildren
aremoresusceptibletodiseases,pollutedsoilposesagreaterthreatto
them.Someimportanteffectsofsoilpollutionaredetailedinthis
subsection.
EffectsonHumanBeings
Soilcontaminantscanexistinallthreephases(solid,liquid,andgaseous).
Therefore,thesecontaminantscanfindtheirwayintothehumanbodyvia
severalchannelssuchasdirectcontactwiththeskinorthroughthe
inhalationofcontaminatedsoildust.
Theshorttermeffectsofhumanexposuretopollutedsoilinclude:
•Headaches,nausea,andvomiting.
•Coughing,paininthechest,andwheezing.
•Irritationoftheskinandtheeyes.
•Fatigueandweakness.

33. Avarietyoflong-termailmentshavebeenlinkedtosoil
pollution.Somesuchdiseasesarelistedbelow.
•Exposuretohighlevelsofleadcanresultinpermanent
damagetothenervoussystem.Childrenareparticularly
vulnerabletolead.
•DepressionoftheCNS(CentralNervousSystem).
•Damagetovitalorganssuchasthekidneyandtheliver.
•Higherriskofdevelopingcancer.
Itcanbenotedthatmanysoilpollutantssuchas
petroleumhydrocarbonsandindustrialsolventshavebeen
linkedtocongenitaldisordersinhumans.Thus,soil
pollutioncanhaveseveralnegativeeffectsonhuman
health.

34. EffectsonPlantsandAnimals
Sincesoilpollutionisoftenaccompaniedbyadecreaseintheavailabilityofnutrients,plantlifeceasesto
thriveinsuchsoils.Soilscontaminatedwithinorganicaluminiumcanprovetoxictoplants.Also,thistype
ofpollutionoftenincreasesthesalinityofthesoil,makingitinhospitableforthegrowthofplantlife.
Plantsthataregrowninpollutedsoilmayaccumulatehighconcentrationsofsoilpollutantsthrougha
processknownasbioaccumulation.Whentheseplantsareconsumedbyherbivores,alltheaccumulated
pollutantsarepassedupthefoodchain.Thiscanresultintheloss/extinctionofmanydesirableanimal
species.Also,thesepollutantscaneventuallymaketheirwaytothetopofthefoodchainandmanifestas
diseasesinhumanbeings.
EffectsontheEcosystem
•Sincethevolatilecontaminantsinthesoilcanbecarriedawayintotheatmospherebywindsorcan
seepintoundergroundwaterreserves,soilpollutioncanbeadirectcontributortoairandwater
pollution.
•Itcanalsocontributetowardsacidrain(byreleasinghugequantitiesofammoniaintotheatmosphere).
•Acidicsoilsareinhospitabletoseveralmicroorganismsthatimprovesoiltextureandhelpinthe
decompositionoforganicmatter.Thus,thenegativeeffectsofsoilpollutionalsoimpactsoilqualityand
texture.
•Cropyieldisgreatlyaffectedbythisformofpollution.InChina,over12milliontonsofgrain(worth
approximately2.6billionUSD)isfoundtobeunfitforhumanconsumptionduetocontaminationwith
heavymetals(asperstudiesconductedbytheChinaDialogue).

35. HowcanSoilPollutionbeControlled?
Severaltechnologieshavebeendevelopedtotacklesoilremediation.
Someimportantstrategiesfollowedforthedecontaminationof
pollutedsoilarelistedbelow.
•Excavationandsubsequenttransportationofpollutedsoilstoremote,
uninhabitedlocations.
•Extractionofpollutantsviathermalremediation–thetemperatureis
raisedinordertoforcethecontaminantsintothevapourphase,after
whichtheycanbecollectedthroughvapourextraction.
•Bioremediationorphytoremediationinvolvestheuseof
microorganismsandplantsforthedecontaminationofsoil.
•Mycoremediationinvolvestheuseoffungifortheaccumulationof
heavymetalcontaminants.

36. WhatIsRadioactivePollution?
DEFINITION
RadioactivePollutionisdefinedastheincreaseinthenatural
radiationlevelscausedbyhumanactivities.Itisestimatedthatabout
20%ofradiationweareexposedtoisduetohumanactivities.The
humanactivitiesthatcanreleaseradiationinvolveactivitieswith
radioactivematerialssuchasmining,handlingandprocessingof
radioactivematerials,handlingandstorageofradioactivewaste,as
wellastheuseofradioactivereactionstogenerateenergy(nuclear
powerplants),alongwiththeuseofradiationinmedicine(e.g.X-rays)
andresearch.Butwhataboutmicrowaves,cellphones,radio
transmitters,wirelessdevices,computers,andothercommon
commoditiesoftoday’slife?

37. Whenwethinkofradiation,weimaginebombsandnuclear
explosions.Whiletheseareserioussourcesofhighlevelsradiation(of
highenergy),therearemanyothersourcesthataremuchmore
common,practicallyubiquitous,thatgeneratelowlevelsofradiation
andwhichbasicallyremainunnoticed.Howmanyofusthinkfor
exampleofcellularphonesasasourceofradiation?Andyet,thecell
phones,cellphonetowers,cordlessphones,aswellasTVs,computers,
microwaveovens,broadcastantennas,militaryandaviationradars,
satellites,andwirelessinternetareallsourcesofradiation.Andsoare
thecommonmedicalX-Rays.Consideringthis,thepictureofradiation
pollutionsignificantlyexpands.Fromafewexplosionsandnuclear
accidentshappeningrelativelyrarelyinfarawayplaces,thepictureof
radiationpollutionexpandstoacomplexmatrixcoveringalltheEarth
andthusinvolvingallofuseverywhere!Inthiscontext,wecouldask
ourselves:isradiationreallysobad?Yet,ifitwere,wouldn’tweallbe
deadorsickbynow?!

38. Radiationisessentiallyenergythattravelsandspreadsoutasit
goes.Thisisreferredtoaselectromagneticradiation.Examplesinclude
visiblelight,radiowaves,microwaves,infraredandultravioletlights,X-
rays,andgamma-rays.Thedifferencesbetweenthesevarioustypesof
radiationconsistofsomephysicalpropertiessuchasenergy,frequency,
andwavelength.Thus,thereareavarietyofelectromagneticradiations.
Thismeansthatanyandallthesetypesofradiationcangenerate
radiationpollutioniftheyareenhancedbyhumanactivities.However,the
magnitudeofthepollutiongeneratedvaries,withhigher-riskpollution
generatedbyradiationofhigherenergysuchasgamma-raysregardlessof
exposuretime.Thisradiationisgeneratedthroughdetonationofnuclear
weaponsorinpowerplants.Therefore,themeaningofradiationpollution
isthat,whilethereareubiquitoussourcesofradiation,itismostlythe
high-energyradiationthatcausesradiationpollution,carryingserious
healthrisks(suchascancerordeath).Thisiswhywewillfocusonsources
forhighhealth-riskradiationwhendiscussingthecausesofradioactive
pollutionanditseffects.However,theothertypesofradiation(inlow
dosesoverlongertime)maystillcausehealthproblems,including
neurological,reproductive,andcardiacdysfunctions.

39. TypesofRadioactivePollution
Basedonthefrequencywithwhichitoccurs,radioactivepollutioncan
becontinuous,occasionaloraccidental.
Continuouspollution
Continuousradioactivepollutionisthetypeofpollutionconstantly
comingfromuraniummines,nuclearreactors,andtestlaboratories,where
theradioactivecontaminantsarealwayspresent.
Occasionalpollution
Occasionalradioactivepollutionisthetypeofpollutionthatoccurs
duringnucleartestsorduringexperimentaltestsonradioactivesubstances.
Accidentalpollution
Accidentalradioactivepollutionisthetypeofpollutionthatoccurs
whencertainexperimentsinvolvingdangeroussubstancesfail,andthe
substancesusedforexperimentationgetoutofcontrol.

40. ExamplesofRadioactiveContaminants
Radioactivematerialsarethosematerialsorelementsthatemit
radiation,thustheyarenotstableandgettransformedintoother
radioactiveornon-radioactivematerials.Theharmthattheycancause
dependsontheradioactiveelementsandtheirhalftimefunction(the
timeneededfortheirconcentrationtobereducedtohalfdueto
radioactivedecayprocesses).Basically,thehigherthehalf-time,the
lowertheeffectsonhumanhealth.Radioactiveelementswithashort
andveryshorthalf-timeposeaseriousthreattohumanhealth
becauseoftheirhazardouseffects.Mostoftheradioactivematerials
havehalf-livesofhundredsofthousandsofyearsand,oncegenerated,
maypersistintheenvironmentforaverylongtime.
Manyradioactiveelements(materials)arenaturallypresentin
theenvironment.Mostofthemareusedinnuclearpowerplants,and
asbasiccomponentsofnuclearweapons.Examplesofthistypeof
materialsare:

41. CAESIUM-137:Usedforradiationtherapyinmedicine(totreatcancer).
STRONTIUM-90:Usedforthermoelectricgeneratorsandportable
powersourcesforspacevehicles,weatherstationsetc.
PLUTONIUM-238:Usedasaheatsourceforradioisotope
thermoelectricgenerators.
URANIUM-235:Usedasfuelfornuclearreactors.
Otherexamplesofradioactiveelementsinclude:
CHROMIUM-51:Usedastraceableradiationthatcanindicatevarious
medicalparameters.
COBALT-57&60:Usedinnuclearmedicine.
CALCIUM-47:Usedinbiomedicalresearch.

42. TheEffectsofRadioactivePollution
Dependingontheamountofradiationtowhichweareexposedandthe
sensitivityofeachexposedperson,theeffectsofradioactivepollutioncanvary
significantlybetweenindividuals.Whiletheexposuretohighamountsofradiation
generatesalmostimmediatelychronicdiseases,cancerorevensuddendeathin
rarecasesofextremepollution,smallamountsofradiationcancausediseasesthat
arenotsoseriousanddevelopoverthecourseoftime.Theriskofdeveloping
cancerincreaseswiththedoseofradiation,butlowerdosesofradiationcanalso
causecancerafteryearsofexposure.
ExposuretoradonisthesecondleadingcauseoflungcancerintheU.S.!
(pleasenotethattheriskofdevelopinglungcancerincreaseswithsmoking).Also,
theexposuretoothersimilarradioactivematerialscangenerateneurological,
reproductiveorheartproblems.Thesemayormaynotbefollowedbycancer.Ifthe
parentsareexposedtoradiationbeforeorduringpregnancy,geneticbirthdefects
andretardationmayoccurinthefetus.
Geneticinheritanceplaysanimportantroleinhowsensitiveanindividual
maybetoradiation-basedpollution.However,anyamountofradiationmaycause
cancer,andanyexposuretoradiationmaycausesomehealthrisks.Thus,itis
alwayssafertominimizeasmuchaspossibletheexposuretoradiation!