简介：Dustemissionsfromsmelters,asamajorcontributortoheavymetalcontaminationinsoils,couldseverelyinfluencesoilquality.Downwindsurfacesoilswithin1.5kmofazincsmelter,whichwasactivefor10yearsbutceasedin2000,inMaguTown,GuizhouProvince,ChinawereselectedtoexaminePb,Zn,andCdconcentrationsandtheirfractionationalongadistancegradientfromazincsmelter,andtostudythepossiblee?ectsofPb,Zn,andCdaccumulationonsoilmicroorganismsbycomparingwithareferencesoillocatedatadownwinddistanceof10kmfromthezincsmelter.Soilswithin1.5kmofthezincsmelteraccumulatedhighlevelsofheavymetalsZn(508mgkg-1),Pb(95.6mgkg-1),andCd(5.98mgkg-1)withlowratiosofZn/Cd(59.1-115)andPb/Cd(12.4-23.4).Compositepollutionindices(CPIs)ofsurfacesoils(2.52-15.2)were3to13timeshigherthanthereferencesoils.Inmetalaccumulatedsoils,exchangeablepluscarbonate-boundfractionsaccountedformorethan10%ofthetotalZn,Pb,andCd.Thesaturationdegreeofmetals(SDM)insoilswithin1.5kmofthesmelter(averaging1.25)wassixtimeshigherthanthatofthereferencesoils(0.209).Asmallersoilmicrobialbiomasswasfoundmorefrequentlyinmetalaccumulatedsoils(85.1-438μgCg-1)thaninreferencesoils(497μgCg-1),andanegativecorrelation(P<0.01)ofsoilmicrobialbiomasscarbontoorganiccarbonratio(Cmic/Corg)withSDMwasobserved.Microbialconsumptionofcarbonsourceswasmorerapidincontaminatedsoilsthaninreferencesoils,andashiftinthesubstrateutilizationpatternwasapparentandwasnegativelycorrelatedwithSDM(R=-0.773,P<0.01).Consequently,dustdepositedPb,Zn,andCdinsoilsfromzincsmeltingwerereadilymobilized,andweredetrimentaltosoilqualitymainlyinrespectofmicrobialbiomass.

简介：FixedammoniumcontentsandNH4^+fixationcapacitiesofsomerepresentativecultivatedsoliscollectedfrom16provincesofChinawerestudied.Resultsshowedthatthecontentsoffixedammoniuminsoilsrangedfrom35to573mgNkg^-1,withanaverageof198mgNkg^-1.Thecontentoffixedammoniumcorrelatedverysignificantlywithmicacontentfortropicalandsubtropicalsoils,whereasthiswasnotthecaseforsoilsinthetemperatezone.AttheendofK-exhaustingexperimentthefixedammoniumcontentincreasedinmostsoilsstudied.However,itdecreasedinsmomtemperatesoils.Generally,fixationofaddedNH4^+couldnotbefoundeitherbeforeorafterK-exhaustingexperimentforhighlyweatheredsoils,includingtropicalsoilsandsoilsderivedfromgranite-gneissorQuaternaryredclaysinthesubtropiczone,whileformostsoilsintheYangtzeRiverdaltatheNH4^+fixationcapacitywasratherhighandincreasedsignificantlyintheK-exhaustedsoils.

简介：针对于弃渣场的排洪设计，本文对洪屏抽水蓄能电站下库4#弃渣场分别采取箱涵、管涵及明渠等排洪设施，通过对3种排洪设施的设计及选型分析，可以看出：对山谷型高边坡弃渣场排洪设施设计时，明渠排洪具有投资抵、施工难度小、后期维护简单、可操作性强等优点，宜采用以明渠排导为主，辅以箱涵、管涵等临时排水设施的排洪体系进行弃渣场排洪设计。