环境工程专业英语文章1

3672nEnvironmEntalSciEncE&tEchnology/junE15,2006junE15,2006/EnvironmEntalSciEncE&tEchnologyn3673MERCURYPOLLUTIONinChinaAnoverviewofthepastandcurrentsourcesofthetoxicmetal.thropogenicemissionsfromindustryandagricul-tureandfrommedicalanddomesticsources(3).ChinahasalonghistoryofminingandusingHg.Twothousandyearsago,cinnabar(HgS)wastakenbytheChinesebecauseitwasbelievedtoprolonglife.CinnabarisstilloftenusedtodayinChinaasaredpigment,drug,andpreservative.Withtherapiddevelopmentofindustryandagricultureduringthepasttwodecades,theamountofHgconsumedinChinahasincreasedsignificantly.TotalHg(THg)consumptioninChinawas900tin2000,~50%ofworldwideproduction.Meanwhile,Chinaisthelargestproducerandconsumerofcoalintheworld.Asof2003,Chinaconsumednearly1531Mtofcoal,~28%oftheworld’stotalconsumption.China’sannualcoalconsump-tionisalsoexpectedtodoubleto3037Mtby2020(4).Therefore,ChinaplaysanimportantroleinglobalanthropogenicHgemissions.ThelargeamountofHgemittedfromChinamaybecomeathreattotheglobalenvironment(5,6).TherisinganthropogenicemissionshaveledtoseriousHgpollutioninChina.Theaimofthisfea-GUI-BINJIANGSTATEKEYLABORATORYOFENVIRONMENTALCHEMISTRYANDECOTOXICOLOGY,RESEARCHCENTERFORECO-ENVIRONMENTALSCIENCES,CHINESEACADEMYOFSCIENCESJIAN-BOSHISTATEKEYLABORATORYOFENVIRONMENTALCHEMISTRYANDECOTOXICOLOGY,RESEARCHCENTERFORECO-ENVIRONMENTALSCIENCES,CHINESEACADEMYOFSCIENCESANDTHEHONGKONGPOLYTECHNICUNIVERSITYXIN-BINFENGINSTITUTEOFGEOCHEMISTRY,CHINESEACADEMYOFSCIENCESMercury(Hg)isatoxicelement.Inthe1960s,residentsofMinamata,Japan,developedsevereneuropathiesfromtheconsumptionofmethylmercury(MeHg)-contaminatedseafood.ItisnowcalledMinamatadisease,and2217caseshadbeenofficiallyrecognizedinthecityby1989(1).Hgpollutionepisodeshavealsooccurredinothercountries,suchasIraq,Brazil,Indonesia,theU.S.,andChina.TheU.S.EPAestimatesthateveryyearintheU.S.630,000infantsarebornwithunsafelevelsofHgintheirblood(2).Asaresult,Hgisnowcon-sideredakeyglobalpollutant.Becauseofitspersis-tence,bioaccumulation,andtoxicity(PBT)intheenvironment,Hgislistedasaprioritypollutantbymanyinternationalagencies.AlthoughsomenaturalemissionsofHgcomefromvolcanoes,forestfires,andsoilandwaterthroughevaporation,anthropogenicemissionsarethemainsource.ArecentglobalassessmentfromtheUNEnvironmentProgrammehasdocumentedthatthedepositionrateofHghasgrownby1.5–3×duringthepastcenturybecauseofincreasedan-©2006americanchemicalSocietyJIN-LILI3674nEnvironmEntalSciEncE&tEchnology/junE15,2006tureistodescribetheHgemissionsandpollutioninChina.Inaddition,issuesrelatedtothecurrentmanagementpolicyandfutureresearchperspec-tivesarediscussed.HgemissionsandpollutionAsia,especiallyChina,hasbeenregardedastheworld’slargestatmosphericHgemissionsource.PacynaandPacynaestimatedthatin1995,Asiancountriescontributed56%oftheworldwideTHgemissions,comparedwith~30%in1990(7,8).TheincreaseinemissionsinAsiawasclearlyrelatedtothegrowthofcoalcombustioninChina.Streetsetal.recentlycompiledaninventoryofanthropogenicHgemissionsinChinaandestimat-edthecountry’stotalemissionsat536±236tin1999(9).Approximately45%oftheHgcomesfromnonferrousmetalsmelting,38%fromcoalcombus-tion,and17%frommiscellaneousactivities.How-ever,todate,veryfewstudieshavebeenconductedtodetermineHgemissionfactorsfromdifferentsourcesinChina.Asaresult,emissionfactorsaretypicallyadoptedfromstudiesconductedinEuropeandNorthAmericawithroughlysimilarsources.Becausetheprocessesandpollution-controltech-niquesusedinChinamaydifferdramaticallyfromthoseusedindevelopedcountries,theseadoptedHgemissionfactorscoulddiffersignificantlyfromtheactualfieldconditionsinChina.Thus,alargeuncertaintycouldexistinChina’santhropogenicHgemissionsinventories.Mining(gold[Au]andHg),chemicalindustry,andcoalcombustionarethemoreimportantanthropo-genicsources.TheHgemissionsandpollutionfromtheseactivitiesarebrieflypresentednext.HgandAuminingChinaisrichinHgmineralresources,rankingthirdintheworld.MostHgoresaredistributedinsouthwesternandcentralChina,mainlyinGuizhou,Shanxi,Henan,andSichuanProvinces.About70%oftheHgisfoundinGuizhouProvince,wherethemetalhasbeenminedfor600yr.THgemissionstoairfromminingactivitiesinGuizhouProvincealonewere~11tin1983buthaddeclinedto~5tby1994(10).Wanshan,locatedineasternGuizhouProvince,isknownasthe“capitalofmercury”becauseithasthelargestdepositsofHginChina.TheTHgproducedinWanshanfromthe1950stothe1990swas~20,000t.Thecity’slonghistoryofHgminingandsmelt-inghasresultedinsignificantpollutionofthelocalecosystem.ConcentrationsofHginsoilrangefrom24.3to348mg/kg(11),whichis16–232×themaxi-mumHgconcentrationallowedforsoilinChina(1.5mg/kg,NationalStandardGB15618-1995).Hgcon-centrationsinriverwaterandplantsintheareaarealsoelevated,rangingfrom3.2to680ng/L(11–13)and0.47to331mg/kg,respectively(11).Horvatetal.foundthattheconcentrationsofTHgandMeHginricegrainsfromWanshancanreachupto0.57and0.14mg/kg,respectively(12).AlthoughHgminingceasedin2001,100MtofcalcinesandotherwasterockshasbeenproducedasaresultofmininginWanshan.ThephotographatleftshowsminingresiduesinWanshan.TheHgconcentrationsoftheseresiduesarerelativelylow