英语六级阅读

Facingwatershortagesandescalatingfertilizercosts,farmersinDevelopingcountriesareusingrawsewagetoirrigateandfertilizenearly49millionacresofcropland,accordingtoanewreportanditmaynotbeabadthing.Whilethepracticecarriesserioushealthrisksformany,thosedangersareoutweighedbythesocialandeconomicgainsforpoorurbanfarmersandconsumerswhoneedaffordablefood.Thereisalargepotentialforwastewateragriculturetobothhelpandhurtgreatnumbersofurbanconsumers,saidLiqaRaschid-Sally,wholedthestudy.Thereportfocusedonpoorurbanareas,wherefarmsinornearcitiesSupplyrelativelyinexpensivefood.Mostoftheseoperationsdrawirrigationwaterfromlocalriversorlakes.Unlikedevelopedcit短缺不断升级的肥料成本未经处理的污水灌溉施肥亩农田虽然这种做法给许多人带来严重的健康风险，但贫穷的城市农民和需要负担得起的食物的消费者的社会和经济收益超过了这些危险。潜在ies,however,theseareaslackadvancedwater-treatmentfacilities,andriverseffectivelybecomesewers(下水道).Whenthiswaterisusedforagriculturalirrigation,farmersriskabsorbingdisease-causingbacteria,asdoconsumerswhoeattheproducerawandunwashed.Nearly2.2millionpeopledieeachyearbecauseofdiarrhea-related(与腹泻相关的)diseases,accordingtoWHOstatistics.Morethan80%ofthosecasescanbeattributedtocontactwithcontaminatedwaterandalackofpropersanitation.ButPayDrechsel,anenvironmentalscientist,arguesthatthesocialandeconomicbenefitsofusinguntreatedhumanwastetogrowfoodoutweighthehealthrisks.Thosedangerscanbeaddressedwithfarmerandconsumereducation,hesaid,whilethefreewaterandnutrientsfromhumanwastecanhelpurbanfarmersindevelopingcountriestoescapepoverty.Agricultureisawater-intensivebusiness,accountingfornearly70%ofglobalfreshwaterconsumption.Inpoor,dryregions,untreatedwastewateristheonlyviableirrigationsourcetokeepfarmbusiness.Insomecases,waterissoscarcethatfarmersbreakopensewagepipestransportingwastetolocalrivers.Irrigationistheprimaryagriculturaluseofhumanwasteinthedevelopingworld.Butfrequentlyuntreatedhumanwasteharvestedfromlavatoriesisdeliveredtofarmsandspreadasfertilizer.Inmostcases,thehumanwasteisusedongraincrops,whichareeventuallycooked,minimizingtheriskoftransmittingwater-bornediseases.Withfertilizerpricesjumpingnearly50%permetrictonoverthelastyearinsomeplaces,humanwasteisanattractive,andoftennecessary,alternative.Incaseswheresewagemudisused,expensivechemicalfertilizerusecanbeavoided.Themudcontainsthesamecriticalnutrients.Overlystrictstandardsoftenfail,JamesBartram,aWHOwater-healthexpert,said.Weneedtoacceptthatfactacrossmuchoftheplanet,sowastewithlittleornotreatmentwillbeusedinagricultureforgoodreason.