可持續(xù)發(fā)展經(jīng)濟的介紹之循環(huán)經(jīng)濟的講解environment

可持續(xù)發(fā)展經(jīng)濟的介紹之循環(huán)經(jīng)濟的講解environmentKeyConceptsTypes,sources,andeffectsofwaterpollutantsMajorpollutionproblemsofsurfacewaterMajorpollutionproblemsofgroundwaterReductionandpreventionofwaterpollutionDrinkingwaterquality2Types,Effects,andSourcesofWaterPollution

Waterispollutedbyinfectiousbacteria,inorganicandorganicchemicals,andexcessheat.Waterpollutionisanychemical,biological,orphysicalchangeinwaterqualitythathasaharmfuleffectonlivingorganisms.TheWHOestimatesthat3.4millionpeopledieprematurelyeachyearfromwaterbornediseases.IntheU.S.,anestimated1.5millionpeopleayearbecomeillfrominfectiousagents.3Scientistsmonitorwaterqualitybyusingbacterialcounts,chemicalanalysis,andindicatororganisms.Onemethodofmeasuringwaterqualityinvolvesmeasuringthenumberofcoloniesoffecalcoliformbacteriapresentinawatersle.Drinkingwatershouldnotcontainanycolonies/100milliliters,Chemicalanalysisincludescheckinginorganicandorganicchemicalspresent,sedimentcontent,andturbidityofwater.Indicatorspeciesarelivingorganismsthataremonitoredtodeterminelevelsofpollution.4SourcesofWaterPollutionPointsourcesNonpointsourcesWaterquality5PointandNonpointSourcesNONPOINTSOURCESUrbanstreetsSuburbandevelopmentWastewatertreatmentplantRuralhomesCroplandFactoryAnimalfeedlotPOINTSOURCES6SourcesofwaterpollutionTheleadingsourcesofwaterpollutionareagriculture,industries,andmining.1. Agriculturalactivitiesaretheleadingcauseofwaterpollutionfromerosion,overgrazing,fertilizersandpesticides,andexcesssaltfromirrigatedsoils.2. Industrialfacilitiesareanotherlargesourceofwaterpollution,andminingisathirdsource.7Oneofeveryfivepeopleintheworldlacksaccesstosafedrinkingwater.Ninety-fivepercentofpeopleindevelopedcountriesand74%ofpeopleindevelopingcountrieshaveaccesstocleandrinkingwater.Inawarmerworld,toomuchrainandtoolittleraincanincreasewaterpollution.

8PollutionofFreshwaterStreams

Streamscanrecoverfrommoderatelevelsofdegradablewaterpollutantsiftheflowsarenotreduced.1. Acombinationofdilutionandbiodegradationcanallowrecoveryofstreampollution2. Thebreakdownofpollutantsbybacteriacreatesanoxygensagcurve.Organismsthathaveahighoxygendemandcan’tsurviveinthecurve.3. Volumeofthestream,volumeofwastesentering,flowrate,temperature,andpHlevelsallaffecthowgreatasagcurveisproduced.9OxygenSagCurve10WaterPollution:NowMostdevelopedcountrieshavereducedpointsourcepollution,buttoxicchemicalsandpollutionfromnon-pointsourcesarestillproblems.Streampollutioninmostdevelopingcountriesisaseriousandgrowingproblem.Halfoftheworld’s500majorriversareheavilypolluted,andmostofthemrunthroughdevelopingcountrieswherewastetreatmentisminimalornonexistent.Forexle:Religiousbeliefs,culturaltraditions,poverty,littleeconomicdevelopment,andalargepopulationinteracttocauseseverepollutionoftheGangesRiverinIndia.11PollutionofLakes12TheGreatLakesFig.22-8p.50013GroundwaterPollution:CausesLowflowratesFewbacteriaColdtemperaturesCoalstripminerunoffPumpingwellWastelagoonAccidentalspillsGroundwaterflowConfinedaquiferDischargeLeakagefromfaultycasingHazardouswasteinjectionwellPesticidesGasolinestationBuriedgasolineandsolventtankSewerCesspoolseptictankDe-icingroadsaltUnconfinedfreshwateraquiferConfinedfreshwateraquiferWaterpumpingwellLandfillLowoxygen14PollutionofGroundwater

Expertsrategroundwaterpollutionasalow-riskecologicalproblem;itisratedasahigh-riskhealthproblem.Theextentofgroundwatercontaminationisgenerallyunknown

Preventionisthemosteffectiveandaffordablewaytoprotectgroundwaterfrompollutants.15OceanPollutionFig.22-11p.50416CaseStudy:ChesapeakeBayLargestUSestuaryRelativelyshallowSlow“flushing”actiontoAtlanticMajorproblemswithdissolvedO217OilSpillsSources:offshorewells,tankers,pipelinesandstoragetanksEffects:deathoforganisms,lossofanimalinsulationandbuoyancy,smotheringSignificanteconomicimpactsMechanicalcleanupmethods:skimmersandblottersChemicalcleanupmethods:coagulantsanddispersingagents18Solutions:PreventingandReducingSurfaceWaterPollutionNonpointSourcesPointSourcesReducerunoffBufferzonevegetationReducesoilerosionCleanWaterActWaterQualityAct19TechnologicalApproach:SepticSystemsRequiresuitablesoilsandmaintenance20TechnologicalApproach:Advanced(Tertiary)SewageTreatmentUsesphysicalandchemicalprocessesRemovesnitrateandphosphat