城市污泥重金属形态及其生物有效性的研究的英文文献的翻译.docx
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城市污泥重金属形态及其生物有效性的研究的英文文献的翻译
.3陕西科技大学学报Jun.2008
Vol.26JOURNALOFSHAANXIUNIVERSITYOFSCIENCE&TECHNOLOGY125
*文章编号:
10005811(2008)03012507
STUDYONCHEMICALFRACTIONSANDBIOAVAILABILITY
OFHEAVYMETALSINSEWAGESLUDGE
LIShugeng1,2,ZHANGKefang3,ZHOUShaoqi1,CHENQiuli3,ZHANGLiqiu3
(1.SchoolofEnvironmentalScienceandEngineering,SCUT,Guangzhou510006,China;2.SchoolofEnvi
ronmentalScienceandEngineering,GuangzhouUniversity,Guangzhou510006,China;3.SchoolofCivil
Engineering,GuangzhouUniversity,Guangzhou510006,China)
Abstract:
Thetotalcontentsandchemicalfractionsofheavymetals(Zn,Cu,Cd,Cr,Pb
andNi)insewagesludgewereanalyzedinthepresentstudywithTessier!
sprocedure.The
bioavailabilityoftheseheavymetalswasalsostudiedbypottingplantingofDockleafKnot
weed.TheresultsshowedthatthetotalcontentsofZn,Cu,Cd,Cr,PbandNiwereallless
thantheChinesesewagesludgecriteriaforagriculturaluse(soilpH∀6.5).AsforZn,Cd,
CrandPb,residualfractionwasthepredominantfraction,whileforCuandNi,organicfrac
tionwasthepredominantfraction.TheproportionsofunbioavailableformsofZn,Cd,Cr
andPbweremorethan50%,whichwasfavorableforusingsludgeinagriculture.Theroots
ofDockleafKnotweedcouldaccumulatemoreheavymetalsthanshoots.Theheavymetals
absorbedbypottedplantincludednotonlyexchangeableandcarbonateforms,butalsoiron
manganeseoxidesandorganicformswhichwerereleasedundercertainconditions.
Keywords:
sewagesludge;heavymetals;chemicalfraction;bioavailability;DockleafKnot
weed
CLCNumber:
X705DocumentCode:
A
0Introduction
Sludgeisoneoftheprincipalbyproductsofwastewatertreatmentplants(WWTP).Therearesev
eralwaystohandlethesludge,suchasincineration,landfillinganduseasfertilizerforenergycropsor
inagriculturalfoodproduction.Theuseofsewagesludgeincropproductionisideallyfavorableinasus
tainablesociety,asthiswouldrecycleasubstantialcontentofnutrientsandorganicmatter[1].Howev
er,itsuseforfoodproductionishighlyquestionedduetohealthconcerns.Theoftenhighmetalcon
tentsinsludgewereformerlyseenasprimarilyaproblemofaccumulationinsoilwhenusedforagricul
turalpurposes.Manystudiesshowedthatthetoxicityofheavymetalswasnotonlyrelatingtothetotal
contentsbutalsodependentonthechemicalfractionofheavymetals.Theenvironmentalbehaviorsand
biotoxicityofheavymetalsvaryindifferentchemicalfractionsofheavymetals.
Bioavailabilityofheavymetalsreferstothedegreetowhichthesemetalsareadsorbedoraccumula
tedinorganisms.Totalmetalconcentrationisnotaveryusefulpredictorofbioavailabilityorsoluble
concentrationofthemetal[2,3].Asfaraselementwhichcouldbeadsorbedbyplantinsoilisconcerned,
*收稿日期:
2008-03-17
作者简介:
李淑更(1978-),女,河北省广宗县人,讲师,在读博士生,研究方向:
环境生物技术
基金项目:
广东省科技计划项目(2005B3303008),建设部科技计划项目(2004(149))
陕西科技大学学报第26卷
thecommonmethodforjudgingthebioavailabilityofitistodocorrelationalanalysisbetweenelement
contentinsoilandinplant.Ourobjectiveinthepresentstudywasto:
(1)determinethechemicalfrac
tiondistributionofheavymetals(Zn,Cu,Cd,Cr,PbandNi)insewagesludge;
(2)findtherelation
shipsbetweenthemetalsconcentrationsinthesludgeandmetalcontentinatestplant,DockleafKnot
weed;(3)evaluatethebioavailabilityofthesludge.
1MaterialsandMethods
1.1Characteristicsofthesludge
ThesludgeusedintheexperimentswasobtainedfromtheDatanshawastewatertreatmentplantof
Guangzhoucity(Guangdongprovince,China)inSeptember2006.Thesludgewasairdriedtoconstant
weightpriortosievingthrougha2mmsievebeforeuse.Thephysicalandchemicalpropertiesofthe
sludgearepresentedinTab.1.
1.2Plantgrowthexperiments
Tab.1Physicalandchemicalpropertiesofsewagesludge
watercontent/%pHorganicmatter/%totalnitrogen/%totalphosphorus/%
76.00#1.985.8#0.2440.57#1.741.66#0.051.71#0.08
Notes:
Allvaluesareexpressedinmean#standarddeviationofthreereplicates.
Theplantsweregrown
inpotslocatedinrooms
withsufficientsunlight.
Theplasticspotswerecho
sen,ofwhichdiametersandheightswere11cmand12cm,respectively.Onekgsludgewasputinto
eachpotforplanting,withfivereplications.
TheDockleafKnotweedusedintheexperimentwasthesamekindastheonegrowninthecampus
landscapingareas.Weselectedtheyoungplantsastheexperimentalplantsandgrewoneplantineach
pot.Thepotswerewateredtofieldcapacityat4pmeveryday.Wegrewtheplantfor60days,approxi
mately2months(betweenSeptemberandNovember,2006),undernormaltemperature.Duringthis
period,noadditionalsludgeorsoilwasapplied,noranypesticides.
Atharvesting,plantswereremovedcarefullywithnorootsdamaged.Wewashedtheleavesand
rootswithdeionizedwatertoremoveanyattachedparticles,andthendriedthemat80∃toconstant
weighting.Driedplantssampleswerecrumbledpriortosievingthrougha1mmsievebeforedigestion.
1.3Sampleanalysis
Ouranalysisofthesludgesamplesfollowedthechemicalanalyticalmethodsforsoil[4].Sludgesam
plesweredigestedwithaquaregiaandHClO4first,andthenthetotalheavymetal(Zn,Cu,Cd,Cr,Pb
andNi)contentwasmeasuredwithanatomicabsorptionspectrophotometer(SHIMADZU,AA6800,
Japan).
Tab.2DetailsofTessier!
ssequentialfractionationprocedure(0.5gsludge)
fractionsolutionequilibriumconditions
exchangeable8mL1MMgCl2(pH7.0)1h,roomtemperature
carbonates8mL1MNaOAc(pH5.0)6h,roomtemperature
feandMnoxides8mL0.04MNH2OH/HClin25%(v/v)HOAc6h,96∃
organicmatter3mL0.02MHNO3+5mL30%H2O2(pH2.0)4h,85∃
2mL3.2MNH4OAcin20%(v/v)HNO330min,roomtemperature
residualHNO3digestion
DriedplantsamplesweredigestedinHNO3andHClO4withelectrothermalplate(Guangming,ML
34,China)andheavymetal(Zn,Cu,Cd,Cr,PbandNi)contentsweredeterminedwithanatomicab
sorptionspectrophotometer(SHIMADZU,AA6800,Japan).
Thechemicalfractionsofheavymetals(Zn,Cu,Cd,Cr,PbandNi)insewagesludgewereana
126
第3期李淑更等:
城市污泥重金属形态及其生物有效性的研究
lyzedwithTessier!
sprocedure[5].DetailsofthisprocedurearepresentedinTab.2.
Sampleanalysiswascarriedoutintriplicateandtheresultwasshownwithmeanofthreevalues.
2ResultsandDiscussion
2.1Chemicalfractionsofheavymetalsinsludge
Thechemicalfractionsofheavymetalsinsludgeweremeasuredandtheresultsarepresentedin
Tab.3.Therecovery(in%)wascalculatedastheratiobetweenthesumcontentofallthefractionsand
thetotalcontent.
Tab.3thecontentsofCu、Zn、Pb、Cd、Cr、Niindifferentfractions
ZnCuCdCrPbNi
exchangeablenda23.63#3.760.8#0.30nda25.5#1.536.89#3.47
carbonates75.42#4.5410.95#0.760.14#0.09nda2.71#0.123.75#1.29
feandMnoxides98.58#9.317.75#0.410.25#0.13nda0.15#0.075.38#0.24
organicmatter144.12#2.44152.32#5.980.15#0.0233.51#3.721.17#0.6647.38#0.63
residual371.1#4.6785.38#4.951.86#0.1251.92#6.78109.59#1.5914.78#0.63
sumup689.22280.033.2085.43139.1278.18
totalcontents723.62#8.42289.43#4.953.48#0.30105.54#0.84145.75#0.3486.92#6.16
recovery/%95.2596.7591.9580.9595.4689.94
Chinesequalitystandards1000b500b20b1000b1000b200b
Notes:
Allmetalconcentrationsareexpressedinmg/kg#standarddeviationofthreereplicates;and=notdetected;b
Chinesesewagesludgecriteriaforagriculturaluse(GB428284),SoilpH∀6.5.
AsseeninTab.3,thetotalcontentofZnwasthehighest(723.62mg/kg)amongthesesixmetals.
TheCucontentwasthenexthighestcontent,whichwas289.43mg/kg.ThecontentofCdwasthe
lowestone.AccordingtotheChinesesewagesludgecriteriaforagriculturaluse,allthesemetalconcen
trationswerelessthanthecriterion(soilpH∀6.5).Sothiskindofsludgecouldbeusedincropproduc
tionfromtheviewpointoftotalcontentsofheavymetals.
Thedeterminationoftotalheavymetalcontentofsludgewasnotsufficienttoevaluatethepossible
mobilityandconsequently,thebioavailabilityoftoxicmetalstolivingorganisms[6].Theenvironmental
effectsofheavymetalsvaryindifferentchemicalfractions:
Exchangeablemetalswereeasytotransport
andtransformandcouldbeabsorbedbyplants;CarbonateboundmetalsweresusceptibletopH,itcould
beremobilizedandreleasedintheacidicenvironmentintherhizosphereandbetakenupbycrops[7,8],
andtherefore,couldharmhumanhealththroughthesoilplanthumanbodychain;FeMnoxidesbound
metalswerenoteasytoreleaseundernormalconditionsfortherelativelystrongionicbon