洞庭湖沉积物不同形态氮赋存特征及其释放风险

26620136ＲesearchofEnvironmentalSciencesVol．26No．6June2013．J．2013266598-605．WANGWenwenWANGShuhangJIANGXiaetal．OccurrencecharacteristicsandreleaseriskofnitrogenfractionsinsedimentsofDongtingLakeJ．ＲesearchofEnvironmentalSciences201326659[e-mail]．*[e-mail]111*1211．1000122．150040EN、HNNHNBNBN．．wTN735.91～2846.51mgkg1371.85mgkg、、、wTN1513.43、1173.14、1262.761363.31mgkg．wTNwHN66.74%wNHN21.46%wEN11.80%．、、、wBN189.31、170.16、152.87139.51mgkgwENwHN．、、、NH4+-N6.32、7.03、7.78146.96mgm2·dNH4+-NENNH4+-NHNTN．X524A1001－6929201306－0598－08OccurrenceCharacteristicsandＲeleaseＲiskofNitrogenFractionsinSedimentsofDongtingLakeWANGWen-wen1WANGShu-hang1JIANGXia1WANGYan12WANGJin-zhi11．StateKeyLaboratoryofEnvironmentalCriteriaandＲiskAssessmentChineseＲesearchAcademyofEnvironmentalSciencesBeijing100012China2．SchoolofForestryNortheastForestryUniversityHarbin150040ChinaAbstractAsthesecondbiggestfreshwaterlakeDongtingLakeplaysanimportantroleinfloodwateradjustmentofandwatersupplyforindustryagricultureandlifeinthemiddleandlowerreachesoftheYangtzeＲiver．TheseriouseutrophicationwaspresentedbytheinorganicnitrogeninpreviousstudiesfortheDongtingLake．Howevertheorganicnitrogenformsandreleasewerestillnotclearuntilnow．InordertorevealthespatialdistributionandthereleaseriskofnitrogeninlakesedimentsnitrogenspeciesincludingexchangeablenitrogenENhydrolysablenitrogenHNandnonhydrolysablenitrogenNHNinsurfacesedimentsofDongtingLakewerestudiedbysequentialextractionmethods．ConcentrationandreleasefluxofbioavailablenitrogenBNwerefurthermeasuredtoevaluatethecontributionsofdifferentnitrogenspeciationtoBNandtherelationshipbetweennitrogenspeciationandreleaseflux．Ｒesultsshowedthespatialvariationsinallnitrogenformsinfluencedbyhydrodynamicandlaketopography．TheTNinthewholelakewas735.91-2846.51mgkgwiththemeanvalueof1371.85mgkg．SpecificallythemeanvaluesofTNinEastDongtingLakeWestDongtingLakeSouthDongtingLakeandoutletofDongtingLakewere1513.431173.141262.76and1363.31mgkgrespectively．TheHNNHNandENinsedimentsaccountedfor66.74%21.46%and11.80%ofTNrespectively．ThemeanvaluesofBNinEastDongtingLakeWestDongtingLakeSouthDongtingLakeandoutletofDongtingLakewere189.31170.16152.87and139.51mgkgrespectivelyandBNwasmainlyinfluencedbyENandHN．ThereleasesofammonianitrogeninEastDongtingLakeWestDongtingLakeSouthDongtingLakeandoutletofDongtingLakewere6.327.037.78and146.96mgm2·drespectivelyandweremainlyaffectedbyENespeciallyfortheexchangeableDOI10.13198/j.res.2013.06.19.wangww.0136ammonianitrogen．WhileHNandTNwerenotthemainfactorsinfluencingthenitrogenreleasefromsediments．TheresultscouldeffectivelysupportfortheconstructionofhydraulicengineeringandwaterenvironmentmodelsofDongtingLake．KeywordssequentialextractionnitrogenspeciationsedimentreleaseriskDongtingLake．20112646.1%7.7%1．、2-3．、、、、4-7．．wTN、8-10．EN－9．70.66%～91.69%HN、8.31%～29.34%NHNSON11-12．13．、13-16SON．、－．11.128°44'N～29°35'N、111°53'E～113°05'E2691km21307km26.7m．、、、、、、．、、．2005GB3838—2002《》ⅢρTN、ρTP17．1.22012634℃．157D1～D74N1～N43X1～X31C1．GPS1．48h．1Fig.1SamplingsitesinDongtingLake250g99526100mL10000rmin10min0.45μm－40℃、、1000.149mm10g．1.3《》18．ρDTN－ρNO3－-NρNH4+-N．ρNO2－-NρDON=ρDTN－ρNH4+-N－ρNO3－-N．EN、HNNHN．、1．1Table1MeasurementmethodsofnitrogenspeciationinthesedimentsENE-NH4+-NNH4+-N、E-NO3－-NNO3－-NE-SONSON15g25mL2molLKCl2h0.45μmwE-NH4+-NwE-NO3－-NwEN．wE-SON=wEN－wE-NH4+-N－wE-NO3－-NHNSONAAN、ASN、ANHUN19212g6molLHCl120℃24hpH6.5±0.2wANwAANwASNElson-MorgenwHN．wHUN=wHN－wAN－wAAN－wASNNHNSON32、《》20《》21．333＜5%GBW07303a90%～97%．Excel2010、Origin8.0SPSS17.0、2Fig.2DistributioncharacteristicsofnitrogenspeciationininterstitialwaterfromDongtingLake．22.1．ρDTN、ρNH4+-N、ρNO3－-NρDON2．ρDTN1.00～22.22mgL3.94mgLC1N4C1N3ρNH4+-N0.45～20.44mgL2.47mgLρDTNＲ=0.991n=15P＜0.001ρNH4+-NρDTN50%ρNH4+-NρDTN006690%．ρNO3－-N0.62mgLρDTN20%ρNO3－-ND1、D2ρNO3－-N0.13mgL．NO3－-N．ρDON0.18～1.53mgL0.84mgLρDTN30%．DONDTN、SON22．2.2ENEN－、．wEN3．3ENFig.3DistributioncharacteristicsofexchangeablenitrogeninsedimentsfromDongtingLakewEN87.10～275.06mgkg149.20mgkgN3．ENNH4+-NwE-NH4+-N43.17～160.59mgkg71.13mgkgwEN49%．NH4+-NE-NH4+-N“”．wE-NH4+-NρNH4+-NρENＲ=0.85P＜0.01n=15Ｒ=0.77P＜0.01n=15．wE-NO3－-N16.88mgkgwEN11.5%NO3－-NwNO3－-N923．wE-SON31.12～139.25mgkg61.26mgkgwEN39.51%24wE-SON41.25mgkg．E-SON、、EN、25．2.3HNHN4．4、HNwAAN、wAN、wASNwHUN353.89、334.68、36.31157.81mgkg．wAANwHN41.71%wANwHUN36.74%17.50%wASN4.05%．、、wHN934.79、850.29、840.17785.42mgkg＞＞＞．AANSON10．wAANwHN30.43%～46.03%wHNＲ=0.924n=15P＜0.011012．106264HNFig.4DistributioncharacteristicsofhydrolysablenitrogeninsedimentsfromDongtingLakewAAN．ANwHN31.32%～43.86%D1、D2C1wAN40%．wANwHNＲ=0.988n=15P＜0.01．AN19①2∶1NH4+-N②③、、④．AN12ANAN．ASN226．wASNwHN2.66%～5.70%4.05%9.39%106.42%12wHN．27-28．20d、wASN．wASND1、D2wASN．HUNa-、N-、29．wHUNwHN11.94%～22.89%wHNＲ=0.912n=15P＜0.01．HUNHNAANwHUNHUN30．2.4NHN、TNNHN27．wNHN89.79～1178.38mgkg376.98mgkg．D1、D2wNHNN3．wTN735.91～2846.51mgkg1371.85mgkg．wTN5wTND1、D22840.38mgkg735.91mgkgX33.8、、wTN1513.43、1173.14、1262.761363.31mgkg＞＞＞．wTNwHN56.64%～76.3%66.74%wNHN11.73%～37.62%21.