外文翻译尼罗河体系的水质评价综述.docx

外文翻译尼罗河体系的水质评价综述.docx

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外文翻译尼罗河体系的水质评价综述

中文3790字

附录（外文翻译

）

BIOMEDICALANDENVIRONMENTAL17,87-100（2004）

WaterQualityAssessmentoftheRiverNileSystem:

AnOverview

RIFAATA.WAHAABANDMOHAMEDI.BADAWY

NationalResearchCenter,Dokki,Cairo,Egypt

Objectives：

ThemainobjectiveofthepresentarticleistoassessandevaluatethecharacteristisoftheNilewatersystem，andidentifythemajorsourcesofpollutionanditsenvironmentalandhealthconsequences.Thearticleisalsoaimedtohighlighttheimportanceofwatermanagementviare-useandrecycleoftreatedeffluentsforindustrialpurposeandforcultivationofdesertland.MethodAnintensiveeffortwasmadebytheauthorstocollect,assessandcompiletheavailabledataabouttheRiverNile.Physico-chemicalanalyseswereconductedtocheckthevalidityofthecollecteddata.Forthedeterminationofmicro-pollutants,GasChromatography（GC）andHighPerformanceLiquidChromatography（HPLC）wereused.Heavymetalswerealsodeterminedtoinvestigatethelevelofindustrialpollutionintheriversystem.ResultsTheavailabledatarevealedthattheriverreceivesalargequantityofindustrial,agricultureanddomesticwastewater.Itisworthmentioningthattheriverisstillabletorecoverinvirtuallyallthelocations,withverylittleexception.Thisisduetothehighdilutionratio.Thecollecteddataconfirmedthepresenceofhighconcentrationsofchromiumandmanganeseinallsedimentsamples.Theresiduesoforgano-chlorineinsecticidesweredetectedinvirtuallyalllocations.However,thelevelsofsuchresiduesareusuallybelowthelimitsetbytheWHOforuseasdrinkingwater.ThemostpollutedlakesareLakeMaryutandLakeManzala.Groundwaterpollutioniscloselyrelatedtoadjacent（polluted）surfacewaters.Highconcentrationsofnutrients,Ecoli,sulfur,heavymetals,etc.havebeenobservedintheshallowgroundwater,largelysurpassingWHOstandardsfordrinkingwateruse.ConclusionAregularandcontinuousmonitoringschemeshallbedevelopedfortheRiverNilesystem.Theenvironmentallawshallbeenforcedtoprohibitthedischargeofwastewater（agricultural,domesticorindustrial）toRiverNilesystem.

Keywords:

Waterquality;RiverNile;Lakes;Pollutionsources;Assessment

INTRODUCTION

TheavailabilityofwaterofacceptablequalityinEgyptislimitedandgettingevenmorerestricted,whileatthesametime,theneedsforwaterincreaseasaresultofpopulationgrowth,industrialdevelopmentandcultivationofdesertland.Thecountrydependsformorethan90percentofitswatersupplyontheRiverNile.Groundwaterresourcesarelimitedandthedirectcontributionofrainfall,exceptfortheMediterraneancoastalarea,isneglected.Irrigatedagricultureisbyfarthelargestconsumerofwater（almost90percent）and,althoughadvancesinirrigationandagriculturaltechnologiesstimulatewaterconservation,furtherintensificationofcropschedulesandextensionofagriculturalareasputanincreasingdemandonthealreadyscarcewaterresources.Competingdemandsbetweenindustrialdevelopmentandhumanconsumptionareputtingaseverestrainonabalancedallocationofthelimitedresourcestothevarioususers.

WaterResources

TheRiverNileformsthemainwaterresourceofEgypt.Throughthe1959NileWaterAgreementwithSudanandthecompletionoftheHighAswanDamin1968,astable55.5billionm3/yr.wasallocatedtoEgypt.TheactualreleasefromtheHighAswanDamshowsverylittleyearlyvariation.AnnualvariationofthereleaseofwaterfromtheHighAswanDamdependsmainlyonirrigationneeds.ThereleasefromthehighAswanDamrangesfromapproximately800m3/sduringthe（winter）closureperiodtoapproximately2760m3/sduringthesummermonths.IntheNileValleyandNileDelta,groundwaterresourceusemainlybeingrechargedfromtheNileandfromaccountforapproximately4.4billionm3/yr.,

seepagefromirrigatedagriculture.RainfallsplaysaminorroleinEgypt'swaterresources,withaveragerainfallratesdecliningfrom200millionm3/yr.attheMediterraneanCoastto20mm.inCairoandalmostzeroinUpperEgypt.

WaterConsumption

Inthe1993/94hydrologicalseason,grosswaterconsumptionofirrigatedagricultureamountedtoapproximately54.5B.（billion）m3/yr.（ofwhichalmost30B.m3/yr.occurredintheDelta）.Otherwaterusers,suchasmunicipalanddomesticdrinkingwatersindustryandothersconsumedapproximately8.8B，andanestimated2.0B.about14.0B.waslostthroughevaporationanddischargedtotheMediterraneanSea（Table1）.Inrecentyears,theamountdischargedtotheMediterraneanSeadirectlyfromtheRiverNilesystem,declin3edsharply,infavourofagriculturalanddrinkingwateruseapproximately2.3.mdischargedin1990comparedwithapproximately1.2B.Cuyt3h.erelease.ofwaterfromtheHighAswanDam（HAD）,variesbetween52.9and57.4B.m-iyr.withrncreasmgexpecteduses,Egyptwillnavetorelyongroundwateraquifersandonexpensivedesalinizationofseawater.Thereforetheexistingrenewableresourcesmustbeextremelycarefullymanagedtoadequatelysupplytherapidlyincreasing

populationandindustrialactivity,throughoptionssuchasincreasedefficiencyofirrigationand/orchangesincroptypes,andreducingareasunderirrigation.

ThecurrentwaterusefromtheNileRiverandprojectionstoyear2000showsarapidincreaseindemand,whichisprojectedtobemetbyusingwaterfromthedrainsandreducingtheflowfromdrainstothesea.Thisposesseriousissuessincethewaterinthedrainsiscurrentlyofpoorqualityduetopollutionfromindustrial,municipalandagriculturalsources.

IndustrialPollution

DeteriorationofitssurfaceandgroundwaterduetoEgyptfacesarapidlyincreasingandindustrialeffluentsintoitsdischargesofheavilypolluteddomestic

inagriculturealsocauseswaterwaterways.Excessiveuseofpesticidesandfertilizerspollutionproblems.

Egyptianindustryuses638M.m3/yr.ofwater,ofwhich549M.m3/yr.isdischargedtoactivitiesintheGreaterCairoandAlexandriaregionsusethedrainagesystem.Industrial40%ofthetotal.TheRiverNilesupplies65%oftheindustrialwaterneedsandreceivesmorethan57%ofitseffluents.Moredetailedinformationaboutwaterconsumption,sourcesofpollutionandloadsfromdifferentindustrialwastewaterdischargeandpointsectorsareprovided.

Theareahasapopulationofapproximatelyamillionandencompassesmanyindustrialandcommercialactivities.HeavyindustryislocatedaroundSouthofCairo,and,NorthofCairo.Manysmallindustriesandsomeheavyindustryarerandomlylocatedthroughoutthecity.Althoughwastewaterdischargesofthesmallindustriesaregenerallylow,concentrationsofcertainindustriesinspecificareas,suchasthetanningoverviewcauselocalcontaminationproblems.Anofpollutionsourcesisinclude23chemicalindustries,27textileandspinningindustries,7steelandgalvanizingindustries,32foodprocessingindustries（includingabrewery）,29engineeringindustries,9miningandrefractionindustries,andpetrolandcarservicestations.Bakeries（>350）,marbleandtilefactories（>120）andtanneriesarelocatedinSouthCairo.

Alexandriaisamajorindustrialcenterwithsome175industries,about25percentofthetotalinEgypt.Theseindustriesincludepaper,metal,chemical,textile,plastic,pharmaceutical,oilandsoap,andfoodprocessing.Theseplantsarereportedtocontributesome20percentofthetotalwastewaterofAlexandria.TheindustriesdischargetheireffluentsmainlytoLakeMariutandpardseweragenetwork.AccordingtoasurveymadebyDrainageResearchIntypesofindustrial

lirectlytothelakewastesaredisposedtoLakeMaryut.Atleast17factoriesthroughpipelines;4factoriescollecttheirwastewaterinIlyinginthevicinityofthetreatmentplants;22factoriesdischargingtonearbydrainsandthentothelake.

ItisworthmentioningthatthetotalamountofBODdischargedtotheRiverNilebyindustrialplantsequals270ton/day.Thisamountcorrespondstotheuntreateddischargeofwastewaterfrommorethansixmillionpeople.ItcanbeconcludedthatthesesubstancesaredischargedmainlyfromtheindustrialactivitiesintheGreaterCairoregionandinDelta（0.75and0.50ton/day）.Theaverageconcentrationofheavymetals（HM）intheeffluentislessthan5pg/L,whichisslightlymorethananormalbackgroundfigure（Table2C）.

DomesticPollution

Thewaydomesticpollutionaffectswaterqualityheavilydependsonthewayof

disposalofthispollution.Approximately65percentofEgypt'spopulationisconnectedtodrinkingwatersupplyandonly24percenttosewerageservices,althoughthelatterpercentageisexpectedtogrowrapidly,duetoworksunderconstruction.Thepopulationnotconnectedtoseweragesystemsreliesonindividualmeansofexcretaandwastewaterdisposalsuchaslatrinesandseptictanks.Accordingtoananalysisofthedifferentreferences（WorldBank,1993）,inUpper8wastewatertreatmentfacilitiesexistwithatotalcapacityofroughly120000withapproximatelythesameamountunderconstructionnow.InGreaterCairo,5wastewatertreatmentplantsexist,withatotalcapacityofapproximately1850000m3/day.Inthedeltatherearemorethan30wastewatertreatmentfacilitieswithatotalcapacityofalmost400000,withsome100000m3/dayunderconstruction.InUpperEgyptandintheDelta,somedomesticwastewaterreceivestreatment.IntheGreateronlyprimaryCairoarea,theseweragesystemsalsoservesmallindustriesandcommerce.

AgriculturalPollution

Agriculturalisthemajornon-pointsourcepollution,withanumberofpotentialimpactsontheenvironmentalandhumanhealth.Inmanyagriculturalareas,localsurfaceandgroundw