水体冻结过程中卤乙酸前体物在水-冰体系中的分配研究

中国环境科学2014,34(11)：2773~2780ChinaEnvironmentalScience水体冻结过程中卤乙酸前体物在水-冰体系中的分配研究薛爽,陈静,铁梅*,惠秀娟,张丽娜,张营(辽宁大学环境学院,辽宁沈阳110036)摘要：通过室内模拟试验,研究了水体冻结过程中,水体中溶解性有机物(DOM)和卤乙酸前体物在水-冰体系中的分配规律.按照DOM在XAD树脂上的吸附特性将其分为5个部分:疏水性有机酸(HPO-A),疏水性中性有机物(HPO-N),过渡亲水性有机酸(TPI-A),过渡亲水性中性有机物(TPI-N)和亲水性有机物(HPI).结果表明:在水体冻结过程中,5种DOM组分在水相中的DOC浓度均随冷冻时间的增长而增加,呈现冷冻浓缩效应.与溶解性有机碳(DOC)所表征的整体有机物相比,5种DOM组分中的卤乙酸(HAAs)前体物更倾向于停留在水相中浓缩.在5种DOM组分中,HPI是主要的HAAs前体物.5种DOM组分在未冻结水中的UV-254与HAAFP均表现出一定相关性,其中HPO-A,TPI-A和HPI的UV-254与HAAFP达到极显著水平.然而在融冰水中,这5种DOM组分的UV-254与HAAFP的相关性均不显著.关键词：冻结；溶解性有机物；分级；紫外光谱；卤乙酸前体物中图分类号：X703,TU992文献标识码：A文章编号：1000-6923(2014)11-2773-08Ratioofhaloaceticacidsprecursorinwater-icesystemduringthefreezingprocessesofwater.XUEShuang,CHENJing,TIEMei*,HUIXiu-juan,ZHANGLi-na,ZHANGYing(SchoolofEnvironmentalScience,LiaoningUniversity,Shenyang110036,China).ChinaEnvironmentalScenice,2014,34(11)：2773~2780Abstract：Itwasstudiedthepartitionofdissolvedorganicmatter(DOM)fractionsandhaloaceticacids(HAAs)precursorsinwater-icesystemduringthefreezingprocessesofwaterbytheindoorsimulatingtests.DOMwasfractionatedusingXADresinsintofivefractions:hydrophobicacid(HPO-A),hydrophobicneutral(HPO-N),transphilicacid(TPI-A),transphilicneutral(TPI-N)andhydrophilicfraction(HPI).Theresultsshowedthatthefreezingrateofwatersamplescontainingacidfractionswovehigherthansamplescontainingneutralfractions.DOCconcentrationsforfiveDOMfractionsinliquidphaseincreasedwithfreezingtime,presentingthefreeze-concentrationeffect,duringthefreezingprocessesofwater.HAAsprecursorsweremoreliabletobeconcentratedinliquidphase,ascomparedwiththebulkDOMrepresentedbydissolvedorganiccarbon(DOC).HPI,amongthefiveDOMfractions,wasthemainHAAsprecursors.TherewassignificantcorrelationbetweenUV-254andHAAFPforfiveDOMfractionsinunfrozenliquidsamples.Moreover,forHPO-A,TPI-AandHPIachievedverysignificantlinearcorrelation.However,therewasnosignificantcorrelationbetweenUV-254andHAAFPforallfiveDOMfractionsinmeltedicesamples.Keywords：freeze；dissolvedorganicmatter；fractionation；ultravioletsp