地理专业外语

专业英语课程作业编号⑷2015年10月中旬作业姓名：学号：成绩一、英译汉（共1337字）Waterpollutionisthecontaminationofwaterbodies(e.g.lakes,rivers,oceans,aquifersandgroundwater).Waterpollutionoccurswhenpollutantsaredirectlyorindirectlydischargedintowaterbodieswithoutadequatetreatmenttoremoveharmfulcompounds.Waterpollutionaffectsplantsandorganismslivinginthesebodiesofwater.Inalmostallcasestheeffectisdamagingnotonlytoindividualspeciesandpopulations,butalsotothenaturalbiologicalcommunities.Waterpollutionisamajorglobalproblemwhichrequiresongoingevaluationandrevisionofwaterresourcepolicyatalllevels(internationaldowntoindividualaquifersandwells).Ithasbeensuggestedthatitistheleadingworldwidecauseofdeathsanddiseases,andthatitaccountsforthedeathsofmorethan14,000peopledaily.Anestimatedof580peopleinIndiadieofwaterpollutionrelatedillnesseveryday.[3]Around90%thewaterinthecitiesofChinaispolluted,andasof2007,halfabillionChinesehadnoaccesstosafedrinkingwater.[5]Inadditiontotheacuteproblemsofwaterpollutionindevelopingcountries,developedcountriescontinuetostrugglewithpollutionproblemsaswell.InthemostrecentnationalreportonwaterqualityintheUnitedStates,45percentofassessedstreammiles,47%ofassessedlakeacres,and32percentofassessedbaysandestuarinesquaremileswereclassifiedaspolluted.TheheadofChinasnationaldevelopmentagencyin2007said1/4ththelengthofChina'ssevenmainriversweresopoisonedthewaterharmedtheskin.Wateristypicallyreferredtoaspollutedwhenitisimpairedbyanthropogeniccontaminantsandeitherdoesnotsupportahumanuse,suchasdrinkingwater,orundergoesamarkedshiftinitsabilitytosupportitsconstituentbioticcommunities,suchasfish.Naturalphenomenasuchasvolcanoes,algaeblooms,storms,andearthquakesalsocausemajorchangesinwaterqualityandtheecologicalstatusofwater.Surfacewaterandgroundwaterhaveoftenbeenstudiedandmanagedasseparateresources,althoughtheyareinterrelated.Surfacewaterseepsthroughthesoilandbecomesgroundwater.Conversely,groundwatercanalsofeedsurfacewatersources.Sourcesofsurfacewaterpollutionaregenerallygroupedintotwocategoriesbasedontheirorigin.Pointsourcewaterpollutionreferstocontaminantsthatenterawaterwayfromasingle,identifiablesource,suchasapipeorditch.Examplesofsourcesinthiscategoryincludedischargesfromasewagetreatmentplant,afactory,oracitystormdrain.TheU.S.CleanWaterAct(CWA)definespointsourceforregulatoryenforcementpurposes.TheCWAdefinitionofpointsourcewasamendedin1987toincludemunicipalstormsewersystems,aswellasindustrialstormwater,suchasfromconstructionsites.Nonpointsourcepollutionreferstodiffusecontaminationthatdoesnotoriginatefromasinglediscretesource.NPSpollutionisoftenthecumulativeeffectofsmallamountsofcontaminantsgatheredfromalargearea.Acommonexampleistheleachingoutofnitrogencompoundsfromfertilizedagriculturallands.NutrientrunoffinstormwaterfromsheetflowoveranagriculturalfieldoraforestarealsocitedasexamplesofNPSpollution.Contaminatedstormwaterwashedoffofparkinglots,roadsandhighways,calledurbanrunoff,issometimesincludedunderthecategoryofNPSpollution.However,thisrunoffistypicallychanneledintostormdrainsystemsanddischargedthroughpipestolocalsurfacewaters,andisapointsource.Interactionsbetweengroundwaterandsurfacewaterarecomplex.Consequently,groundwaterpollution,sometimesreferredtoasgroundwatercontamination,isnotaseasilyclassifiedassurfacewaterpollution.Byitsverynature,groundwateraquifersaresusceptibletocontaminationfromsourcesthatmaynotdirectlyaffectsurfacewaterbodies,andthedistinctionofpointvs.non-pointsourcemaybeirrelevant.Aspillorongoingreleasesofchemicalorradionuclidecontaminantsintosoil(locatedawayfromasurfacewaterbody)maynotcreatepointsourceornon-pointsourcepollution,butcancontaminatetheaquiferbelow,definedasatoxinplume.Themovementoftheplume,calledaplumefront,maybeanalyzedthroughahydrologicaltransportmodelorgroundwatermodel.Analysisofgroundwatercontaminationmayfocusonthesoilcharacteristicsandsitegeology,hydrogeology,hydrology,andthenatureofthecontaminants.Thespecificcontaminantsleadingtopollutioninwaterincludeawidespectrumofchemicals,pathogens,andphysicalchangessuchaselevatedtemperatureanddiscoloration.Whilemanyofthechemicalsandsubstancesthatareregulatedmaybenaturallyoccurring(calcium,sodium,iron,manganese,etc.)theconcentrationisoftenthekeyindeterminingwhatisanaturalcomponentofwater,andwhatisacontaminant.Highconcentrationsofnaturallyoccurringsubstancescanhavenegativeimpactsonaquaticfloraandfauna.Oxygen-depletingsubstancesmaybenaturalmaterials,suchasplantmatter(e.g.leavesandgrass)aswellasman-madechemicals.Othernaturalandanthropogenicsubstancesmaycauseturbidity(cloudiness)whichblockslightanddisruptsplantgrowth,andclogsthegillsofsomefishspecies.[11]Manyofthechemicalsubstancesaretoxic.Pathogenscanproducewaterbornediseasesineitherhumanoranimalhosts.Alterationofwater'sphysicalchemistryincludesacidity(changeinpH),electricalconductivity,temperature,andeutrophication.Eutrophicationisanincreaseintheconcentrationofchemicalnutrientsinanecosystemtoanextentthatincreasesintheprimaryproductivityoftheecosystem.Dependingonthedegreeofeutrophication,subsequentnegativeenvironmentaleffect