太湖表层沉积物AVS与SEM分布特征及相互关系.

J.LakeSci.(湖泊科学),2008,20(5):585-590http://www.jlakes.org.E-mail:jlakes@niglas.ac.cn©2008byJournalofLakeSciences太湖表层沉积物AVS与SEM分布特征及相互关系∗尹洪斌1,2,范成新1**,蔡永久1,2(1:中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京210008)(2:中国科学院研究生院,北京100049)摘要:对全太湖28点的表层沉积物中的AVS及SEM的分布特征与相关性进行研究.结果表明:表层沉积物的AVS浓度在空间分布上具有较大的波动(变异系数达100.77%),河口沉积物中赋存高浓度的AVS.结合AVS的分布特征得知:沉积速率及SO42-负荷可能是造成AVS空间差异性的原因.河口区域具有较高浓度的∑SEM;太湖北部湖区沉积物中的∑SEM浓度高于南部.应用SEM/AVS,SEM-AVS及SEM-AVS/fOC这三个模型来评价太湖表层沉积物的质量(当SEM/AVS>9或SEM-AVS>2或SEM-AVS/fOC>150μmol/g(OC)时,沉积物重金属将具有毒性),结果表明:只有0＃号点和6＃号点超过这三个模型其中的一个和两个的阈值范围,其它采样点均在阈值范围之内.总之,除0＃号点和6＃号点外,太湖表层沉积物(约10cm)中重金属不会对底栖生物产生明显毒性.关键词:AVS与SEM;重金属;沉积物质量;太湖DistributioncharacteristicandcorrelationofAVSandSEMinsurfacesedimentsofLakeTaihuYINHongbin1,2,FANChengxin1&CAIYongjiu1,2(1:StateKeyLaboratoryofLakeScienceandEnvironment,NanjingInstituteofGeographyandLimnology,ChineseAcademyofSciences,Nanjing210008,P.R.China)(2:GraduateSchoolofChineseAcademyofSciences,Beijing100049,P.R.China)Abstract:ThedistributioncharacteristicandcorrelationofAVSandSEMwerestudiedin28surfacesedimentsofwholeLakeTaihu.TheresultsshowedthattheconcentrationofAVSvariedgreatlyinspace(COVupto100.77%),andhighconcentrationofAVSwererecordedinestuaryoflake.CombinedwiththedistributioncharacteristicofAVS,depositionrateandloadofSO42-probablycausedthespatialdifferenceofAVS.ThehighconcentrationofSEMwasrecordedintheareaofestuary,andtheconcentrationofSEMinnorthernpartofLakeTaihuwashigherthaninthesouthernpart.ThreemodelsincludingSEM/AVS,SEM-AVSandSEM-AVS/fOC(ToxicitywaspredicatedwhenSEM/AVS>9orSEM-AVS>2orSEM-AVS/fOC>150μmol/g(OC))wereusedtoassessthesedimentqualityofLakeTaihu,andresultsshowedthatonlysite0＃and6＃exceededthethresholdofoneandtwoofthethreemodels.Overall,thesurfacesedimentsofLakeTaihucouldnotcausetoxicitytobenthicorganismexceptsite0#and6＃.Keywords:AVSandSEM;heavymetals;qualityofsediment;LakeTaihu沉积物重金属的毒性与重金属的总量无关而是取决于其在间隙水中的浓度,广大的环境学家对这点已经达成共识.在厌氧沉积物中,酸性可挥发性硫化物(AVS;acidvolatilesulfide)控制着许多二价金属离子在沉积物与间隙水两相间的分配[1].同步可提取金属(SEM;simultaneouslyextr