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一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一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(HPOA)，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fPl—N1和亲水性有机物(I-IeI)．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一254与HAAFP均表现出一定相关性，其中I-IPO—A，TPI—A和HPI的uv一254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)1卜2773—08Ratioofhaloaceticacidsprecursorinwater—icesystemduringthefreezingprocessesofwater．XUEShuang，CHENJing，TIEMei’，HUIXiu-juan，ZHANGLi-na，ZHANGYing(SchoolofEnvironmentalScience，LiaoningUniversitY,Shenyang110036，China)．ChinaEnvironmentalScenice，2014，34(11)：2773-2780Abstract：Itwasstudiedthepartitionofdissolvedorganicma~er(DOM)fractionsandhaloaceticacids(HAAs1precursorsinwater-icesystemduringthefreezingprocessesofwaterbytheindoorsimulatingtests．DOMwasfractionatedusingXADresinsintofivefractions：hydrophobicacid(HPO—A)，hydrophobicneutral(HPO-N)，transphilicacid(TPI—A)，transphilicneutral(TPI-N)andhydrophilicfraction(HPI)．Theresultsshowedthatthefreezingrateofwatersamplescontainingacidfractionswovehigherthansamplescontainingneutralfractions．DOCconcentrationsforfiveDOMfractionsinliquidphaseincreasedwithfreezingtime，presentingthefreeze—concentrationefect，duringthefreezingprocessesofwater．HAASprecursorsweremoreliabletobeconcentratedinliquidphase．ascomparedwiththebulkDOMrepresentedbydissolvedorganiccarbon(DOC)．HPI，amongthefiveDOMfractions，wasthemainHAAsprecursors．ThereWassignificantcorrelationbetweenUV一254andHAAFPforfiveDOMfractionsintinfrozenliquidsamples．Moreover,forHPO-A，TPI—AandHPIachievedverysignificantlinearcorrelation．However,therewasnosignificantcorrelationbetweenUV-254andHAAfPforallfiveDOMfractionsinmeltedicesamples．Keywords：freeze；dissolvedorganicmatter；fractionation；ultravioletspe