葛興彬，王振虹，郭楚奇，孫馨，李鐵龍,*，王薇

1. 南開大學(xué)環(huán)境科學(xué)與工程學(xué)院/天津市城市生態(tài)環(huán)境修復(fù)與污染防治重點實驗室, 教育部環(huán)境污染過程與基準(zhǔn)重點實驗室/天津市生物質(zhì)類固廢資源化技術(shù)工程中心，天津 300071 2. 天津理工大學(xué)環(huán)境科學(xué)與安全工程學(xué)院，天津 300191

?

納米零價鐵的生態(tài)毒性效應(yīng)研究進(jìn)展

葛興彬1，王振虹1，郭楚奇2，孫馨1，李鐵龍1,*，王薇1

1. 南開大學(xué)環(huán)境科學(xué)與工程學(xué)院/天津市城市生態(tài)環(huán)境修復(fù)與污染防治重點實驗室, 教育部環(huán)境污染過程與基準(zhǔn)重點實驗室/天津市生物質(zhì)類固廢資源化技術(shù)工程中心，天津 300071 2. 天津理工大學(xué)環(huán)境科學(xué)與安全工程學(xué)院，天津 300191

納米零價鐵(nZVI)由于其比表面積大、表面反應(yīng)活性高以及強還原性，可以作為一種高效的環(huán)境修復(fù)材料，廣泛運用于污染地下水及土壤修復(fù)。大量的nZVI顆粒直接注射到污染位點會增加生態(tài)系統(tǒng)的暴露可能性，并且由于nZVI粒徑特別小，能穿過細(xì)胞膜和生物體的各類天然屏障，對環(huán)境及生態(tài)系統(tǒng)存在潛在風(fēng)險，因此科學(xué)家們開始更多地關(guān)注nZVI的生物安全性研究。鑒于nZVI在環(huán)境修復(fù)應(yīng)用中的巨大潛力和可能的毒性效應(yīng)，對nZVI環(huán)境風(fēng)險的研究也顯得尤為重要。綜述了近幾年國內(nèi)外關(guān)于nZVI生態(tài)毒性的研究成果，nZVI對病毒、細(xì)菌、微生物群落、以及動植物等都能導(dǎo)致一定的負(fù)面效應(yīng)，盡管其毒性機(jī)制尚不明確，但普遍認(rèn)為nZVI暴露后鐵離子的釋放和氧化損傷確實可以引起生物效應(yīng)，部分研究還分析了環(huán)境因素和表面改性對其毒性的影響。文章對其未來的發(fā)展方向進(jìn)行了展望，以期為今后納米零價鐵的研究提供參考。

納米零價鐵；生態(tài)毒性；氧化損傷；毒性機(jī)制；影響因素

納米零價鐵(nanoscale zero-valent iron，nZVI)是指粒徑小于100 nm的零價鐵的顆粒，由于其較強的反應(yīng)活性能夠快速去除鹵代有機(jī)物、重金屬離子及其他無機(jī)陰離子等多種環(huán)境污染物[1-7]，對持久性有機(jī)污染物也有很好的去除效果[8-12]，并且可以通過直接注射到污染區(qū)域?qū)崿F(xiàn)原位修復(fù)，是一種高效、快速、經(jīng)濟(jì)的土壤及地下水污染修復(fù)材料。國外已在多個場址開展試點，取得了很好的效果[13-15]，國內(nèi)也具有非常大的應(yīng)用潛力，運用nZVI對污染場地進(jìn)行修復(fù)有望成為一種實用的環(huán)境修復(fù)技術(shù)。此外nZVI還能運用于飲用水處理[16]、廢水深度處理[17-18]等領(lǐng)域，為很多環(huán)境難題的解決提供了參考依據(jù)。

nZVI的廣泛應(yīng)用會將大量的nZVI顆粒釋放到環(huán)境中，由于它的粒徑非常小以及強還原性等特性，可能會對生態(tài)環(huán)境造成負(fù)面影響，因此在nZVI大規(guī)模使用之前有必要研究其可能的毒性效應(yīng)，明確其致毒機(jī)制，為nZVI的應(yīng)用以及管理提供依據(jù)和數(shù)據(jù)支持。近年來科學(xué)家陸續(xù)在Science[19-20]、Nature[21-23]、ES&T[24-25]及Toxicology[26-27]、Nanotoxicology[28]等雜志上撰文來探究納米材料的生物毒性效應(yīng)，可見納米毒理學(xué)的相關(guān)研究已經(jīng)引起世界范圍內(nèi)各專家學(xué)者的廣泛關(guān)注。本文從nZVI的毒性效應(yīng)及其機(jī)制，以及nZVI毒性效應(yīng)的影響因素等方面，綜述了近年來國內(nèi)外學(xué)者的研究成果，指出目前存在的問題，并且對今后的研究方向進(jìn)行了展望。

1 nZVI的生物毒性效應(yīng)研究現(xiàn)狀

nZVI的生物安全性研究越來越成為近年來科技工作者關(guān)注的熱點，為了明確其毒性機(jī)制，使之更好的服務(wù)人類，國內(nèi)外的專家學(xué)者在實驗室簡化的條件下對nZVI的毒性效應(yīng)進(jìn)行了大量研究。表1總結(jié)了近幾年國內(nèi)外學(xué)者關(guān)于nZVI毒性效應(yīng)的研究成果。

表1 nZVI對不同生物體的毒性效應(yīng)

續(xù)表1

大鼠SpragueDawleyrats吸入法進(jìn)行染毒，90μg·m-3的nZVI顆粒引起了大鼠的呼吸道反應(yīng)，造成氧化脅迫，并出現(xiàn)了炎癥反應(yīng)的劑量-效應(yīng)關(guān)系Exposuretoironparticlesataconcentrationof90μg·m-3resultedinasignificantdecreaseintotalan?tioxidantpoweralongwithasignificantinductioninferritinexpression，GSTactivity，andIL-1betalevelsinlungscomparedwithlungsoftheFAcontrol，andinhalationofironparticlesleadstooxidativestressassociatedwithaproinflammatoryresponseinadose-dependentmanner．[33]青鳉魚medakafishOryziasLatipes誘導(dǎo)青鳉魚胚胎產(chǎn)生氧化損傷，SOD酶活下降，MDA含量上升，而成體在染毒過程中卻沒有出現(xiàn)明顯的氧化損傷，可能是由于成體具有較強的自我調(diào)節(jié)能力，同時在腮和胃腸道中觀察到組織病理學(xué)以及形態(tài)學(xué)的改變，如細(xì)胞腫脹、畸形、肉芽腫等Dose-dependentdecreasesofsuperoxidedismutase(SOD)andincreasesofmalondialdehyde(MDA)wereinducedinthemedakaembryo，suggestingthatoxidativedamagewasinducedbynano-iron．Noter?minaloxidativedamageoccurredduringthewholeexposureperiod，probablyduetothehighself-recove?ringcapabilityoftheadultfish．Somehistopathologicalandmorphologicalalterations(cellswelling，hy?perplasia，andgranulomas，etc．)wereobservedingillandintestinetissues，whichconfirmedthatdelete?riouseffectsoccurredasaresultofdirectcontactwithnano-iron．青鳉魚的幼體分別暴露于CMC-nZVI和nZVI的溶液中，CMC-nZVI誘導(dǎo)產(chǎn)生更多的活性氧并且釋放更多的Fe2+，因此會導(dǎo)致更高的死亡率以及更強的氧化損傷，而nZVI則具有更強的生物可利用性，RT-PCR的結(jié)果顯示nZVI導(dǎo)致相應(yīng)基因表達(dá)的變化Wetreatedlarvaeofmedakafish(Oryziaslatipes)withthoroughlycharacterizedsolutionscontainingcar?boxymethylcellulose(CMC)-stabilizednanoscalezerovalentiron(nZVI)，agednanoscaleironoxides(nFe-oxides)orferrousion(Fe[II])for12-14days’aqueousexposuretoassessthecausaltoxiceffect(s)ofironNPsonthefish．WiththeCMC-nZVIsolution，thedissolvedoxygenleveldecreased，andaburstofreactiveoxygenspecies(ROS)wasgeneratedasFe(II)oxidizedtoferricion(Fe[III])；withtheothertwoironsolutions，theseparametersdidnotsignificantlychange．CMC-nZVIandFe(II)solutionscausedacutelethallyandsublethallytoxiceffectsinmedakalarvae，withnFe-oxide-containingsolutionscausingtheleasttoxiceffects．[34][35-37]亞麻、大麥、黑麥草Ryegrass，barley，andflaxnZVI對三種植物的毒性效應(yīng)會受到nZVI濃度以及培養(yǎng)介質(zhì)的雙重作用，其在低濃度下并未對種子萌發(fā)造成影響，高濃度則有明顯的抑制作用，在溶液中的抑制最為明顯，沙土次之，而粘土條件下的影響最小FornZVI，germinationtestswereconductedbothinwaterandintwocontrastingsoilstotesttheimpactofassumeddifferencesinbioavailabilityofnanoparticles．Reductioninshootgrowthwasamoresensitiveendpointthangerminationpercentage．Completeinhibitionofgerminationwasobservedat1000-2000mg·L-1fornZVI．Thepresenceofsoilhadamodestinfluenceontoxicity，andinhibitoryeffectswereob?servedat300mg·nZVIL-1waterinsoil(equivalentto1000mg·nZVIkg-1soil)．Completeinhibitionwasobservedat750and1500mg·L-1insandysoilforflaxandryegrass，respectively，whileforbarley13%germinationstilloccurredat1500mg·L-1．Inclaysoil，inhibitionwaslesspronounced．OurresultsindicatethatnZVIatlowconcentrationscanbeusedwithoutdetrimentaleffectsonplantsandthusbesuitableforcombinedremediationwhereplantsareinvolved．[38]香蒲、白楊幼苗Cattail(Typhalatifolia)andhybridpoplars(populousdeltoids×populousnigra)nZVI的毒性效應(yīng)與植物種類和nZVI濃度有關(guān)，低濃度時促進(jìn)植物生長，而高濃度時表現(xiàn)出明顯的抑制作用，nZVI顆粒主要在根部富集，很少向上傳輸PlantseedlingsweregrownhydroponicallyinagreenhouseanddosedwithdifferentconcentrationsofnZ?VI(0-1000mg·L-1)forfourweeks．ThenZVIexhibitedstrongtoxiceffectonTyphaathigherconcen?trations(>200mg·L-1)butenhancedplantgrowthatlowerconcentrations．nZVIalsosignificantlyre?ducedthetranspirationandgrowthofhybridpoplarsathigherconcentrations．Theupwardtransporttoshootswasminimalforbothplantspecies．[39]

續(xù)表1

蚯蚓Earthworms(EiseniafetidaandLumbricusrubellus)急性毒性不強，但在較低濃度下即可影響蚯蚓的繁殖。蚯蚓有明顯的回避行為，體重下降，由于nZVI被氧化的緣故，其負(fù)面效應(yīng)會隨時間延長而降低Regardingavoidance，weightchangesandmortality，bothearthwormspeciesweresignificantlyaffectedbynZVIconcentrations500mg·kg-1soil．Reproductionwasaffectedalsoat100mg·nZVIkg-1．ToxicityeffectsofnZVIwerereducedafteragingwithlargerdifferencesbetweensoilscomparedtonon-agedsoils．[40]跳蟲、介形蟲Collembolaandostracods具有明顯的急性毒性效應(yīng)，但氧化之后毒性會隨之降低，鐵離子的釋放可能是其毒性機(jī)制之一SeverenegativeeffectsofnZVIwereobservedonbothtestorganismsafter7dincubation，butprolongedincubationledtooxidationofnZVIwhichreduceditstoxiceffectsonthetestedorganisms．TheadverseeffectsofnZVIontestedorganismsseemtemporaryandreducedafteroxidation．[41]藍(lán)藻CyanobacterianZVI對藍(lán)藻的毒性效應(yīng)具有“選擇性”，對不同種屬藍(lán)藻的毒性差別較大，能夠破壞藍(lán)藻細(xì)胞，可以有效的預(yù)防水華的產(chǎn)生EcotoxicologicalexperimentsshowedthatnZVIisahighlyselectiveagent，havinganEC50of50mg·L-1againstcyanobacteria；thisis20-100timeslowerthanitsEC50foralgae，daphnids，waterplants，andfi?shes．TheprimaryproductofnZVItreatmentisnontoxicandhighlyaggregatedFe(OH)3，whichpro?motesflocculationandgradualsettlingofthedecomposedcyanobacterialbiomass．[42]細(xì)菌PseudomonasfluorescensEscheriachiacolinZVI的毒性與其表面特性、濃度，以及細(xì)菌種屬和環(huán)境條件等有關(guān)，可以造成細(xì)菌細(xì)胞膜破損，誘導(dǎo)產(chǎn)生活性氧，造成氧化損傷直至細(xì)菌失活，無氧條件下的毒性要顯著強于有氧條件，可能是由于nZVI的氧化產(chǎn)物毒性要小的緣故WhentreateddirectlywithNZVIparticlesunderaerobiccondition，thesurfacesofmicrobeswerequicklycoatedwithneedle-shapeyellow-brownironoxides．Inthisstudy，completeinactivationwasachievedbothforB．subtilisvar．nigerandP．fluorescenswhentreatedwith10mg·mL-1NZVIparticleswithvig?orousshakingunderaerobiccondition．WhenNZVIparticleconcentrationdecreasedto1，0．1mg·mL-1，therewasstillacompleteinactivationforP．fluorescens，whileforB．subtilisvar．nigertheinactivationdecreasedto95%，80%，respectively．However，noinactivationwasobservedforthefungusA．versicolorwhentreatedthesamemanner．Physicalcoating，disruptionofmembraneandgenerationofreactiveoxy?genspecieshaveplayedmajorrolesintheinactivationobserved．[43-48]病毒Viruses可直接導(dǎo)致病毒失活或吸附在其表面通過強烈的吸附力使之失活，從而快速去除污染水體中的病毒Mostofthevirusesremovedfromsolutionwereeitherinactivatedorirreversiblyadsorbedtoiron．Zerov?alentironmaybepotentiallyusefulfordisinfectingdrinkingwaterandwastewater，therebyreducingourdependenceonchlorineandreducingtheformationofdisinfectionbyproducts．[49]微生物群落Microbialcommunity跟微生物生存環(huán)境以及nZVI濃度有關(guān)，對微生物群落結(jié)構(gòu)與組成影響不大，甚至還增強了某些功能細(xì)菌的功能，但是可以改變環(huán)境的某些理化性質(zhì)，如氧化還原電位以及溶解氧等，這也可能是抑制某些細(xì)菌生長的原因nZVI(diameter12．5nm；10mg·g-1soil)apparentlyinhibitedAOPandnZVIandmZVIapparentlystimulateddehydrogenaseactivitybuthadminimalinfluenceonhydrolaseactivity．TherewasnoevidencefornegativeeffectsofnZVIormZVIontheprocessesstudied．WhenexaminingtheimpactofredoxactiveparticlessuchasZVIonmicrobialoxidation-reductionreactions，potentialconfoundingeffectsofthetestparticlesonassayconditionsshouldbeconsidered．[50-54]

由此可見，nZVI的毒性研究已經(jīng)引起了各國學(xué)者的廣泛關(guān)注，已有的研究成果主要表現(xiàn)出以下幾個特點：①大量的研究表明nZVI具有一定的生物毒性效應(yīng)，有必要對其開展相關(guān)毒性研究；②所選擇的受試生物比較單一，且以微生物為主；③研究結(jié)果差異較大，有些研究甚至是得到了相互矛盾的結(jié)論，很難進(jìn)行橫向比較；④選用的研究方法還比較單一，多為在急性毒性試驗的基礎(chǔ)上研究各種生化指標(biāo)的變化，實驗周期比較短，難以模擬實際情況nZVI的毒性效應(yīng)；⑤nZVI顆粒進(jìn)入生物體的方式及其在體內(nèi)的分布、遷移、轉(zhuǎn)化、蓄積、排泄等尚不清楚，仍需加強相關(guān)研究。

當(dāng)一種材料處于納米級時就會具有尺寸效應(yīng)，其表面活性、電子穩(wěn)定性等均會發(fā)生改變，隨之可能帶來與常規(guī)尺寸材料截然不同的生物毒性效應(yīng)，較常規(guī)材料的影響因素也更復(fù)雜，而nZVI本身的活性又很強，性質(zhì)很不穩(wěn)定，不同實驗室使用的材料性質(zhì)可能都是不一樣的，因此很難進(jìn)行橫向的比較，甚至有些之間都是矛盾的，這是制約nZVI毒性研究的最大瓶頸。

2 NZVI的毒性機(jī)制探討

目前，關(guān)于nZVI的致毒機(jī)制尚沒有明確的結(jié)論，就現(xiàn)有的研究成果來看，其可能的機(jī)制主要包括細(xì)胞膜損傷、氧化損傷、有毒離子的釋放、基因損傷等。

2.1 細(xì)胞膜損傷

粒徑小是nZVI的顯著特性之一，也可能是其能夠造成生物毒性效應(yīng)的關(guān)鍵因素。納米顆?？赡芘c細(xì)胞膜上的某些生物大分子結(jié)合，干擾這些生物大分子正常的生理功能，甚至可能干擾細(xì)胞膜上正常的信號傳遞過程[55]；nZVI顆?；蚱溲趸a(chǎn)物可能吸附在細(xì)胞表面，堵塞細(xì)胞膜上的各種離子通道，從而影響細(xì)胞對營養(yǎng)物質(zhì)的攝取以及排泄物的外排[56]；Diao的研究結(jié)果表明nZVI顆粒附著在細(xì)胞表面，可能跟細(xì)胞膜發(fā)生反應(yīng)，從而導(dǎo)致細(xì)菌的失活[43]；nZVI還有可能導(dǎo)致細(xì)胞膜的破碎，從而使得更多的nZVI顆粒進(jìn)入到細(xì)胞中，造成更大的損害，最終導(dǎo)致細(xì)胞失活[47]。粒徑小這一特性使得nZVI顆粒很容易進(jìn)入到生物體甚至是細(xì)胞內(nèi)，跟某些生物大分子發(fā)生反應(yīng)，造成細(xì)胞膜的損傷和細(xì)胞功能異常，進(jìn)而影響生物體正常的生理過程。小尺寸效應(yīng)是納米顆粒的共性，由此導(dǎo)致的細(xì)胞膜破損以及和生活大分子結(jié)合干擾其正常功能，是納米顆粒普遍存在的一種毒性機(jī)制，除此之外，nZVI被氧化之后的粒徑會增大，甚至可能達(dá)到微米級別，附著在細(xì)胞表面，很容易堵塞膜上的一些通道。

2.2 氧化損傷

誘導(dǎo)活性氧(reactive oxygen species, ROS)的產(chǎn)生，造成氧化損傷是目前學(xué)者們比較認(rèn)可的nZVI可能的致毒機(jī)制。納米顆粒本身具有很強的表面活性，在吸收能量或者接觸生物體內(nèi)電子供體時會產(chǎn)生活性氧；同時由于nZVI具有很強的還原性，在細(xì)胞內(nèi)發(fā)生如下反應(yīng)時也會產(chǎn)生大量的活性氧[57-58]：

2Fe(0)+O2+2H2O→2Fe2++4OH-

Fe(0)+O2+2H+→Fe2++H2O2

Fe(0)+ H2O2+2H+→Fe2++H2

(1)

Fe2++O2→Fe3++O2-

Fe2++O2-+2H+→Fe3++H2O2

Fe2++H2O2→oxidant

ROS主要包括1O2、O2-·、H2O2和·OH等，在生物進(jìn)化過程中已經(jīng)形成了包括抗氧化劑和抗氧化酶在內(nèi)的抗氧化防御系統(tǒng)[59]，能夠及時清除體內(nèi)多余的活性氧，維持生物體內(nèi)活性氧的動態(tài)平衡，因此正常新陳代謝過程中產(chǎn)生的活性氧是不會對機(jī)體造成損傷的。然而當(dāng)污染物進(jìn)入體內(nèi)，會誘導(dǎo)產(chǎn)生大量的活性氧物質(zhì)，如若不能及時清除將會在體內(nèi)大量積累，進(jìn)而造成生物體的氧化損傷，可能會導(dǎo)致脂質(zhì)過氧化、DNA損傷、蛋白質(zhì)變性、線粒體受損等后果，甚至引起細(xì)胞的凋亡[60]。早在2006年，Nel[20]等就曾在Science上發(fā)文論述氧化損傷可能是納米材料導(dǎo)致生物毒性效應(yīng)的重要原因。Auffan[47]等通過測定nZVI暴露后大腸桿菌的超氧化物歧化酶活性的變化，推測nZVI的細(xì)胞毒性可能跟造成氧化損傷有關(guān)。王學(xué)[48]等人的研究表明，加入抗氧化劑后nZVI對大腸桿菌的毒性效應(yīng)降低，直觀地表明了氧化損傷是nZVI的致毒機(jī)制。Keenan等人也認(rèn)為nZVI導(dǎo)致人體支氣管上皮細(xì)胞的失活是由于nZVI進(jìn)入細(xì)胞內(nèi)造成了氧化損傷[61]。Zhou等人的研究表明CMC-nZVI對Agrobacteriumsp. PH-08的毒性要明顯弱于裸露的nZVI顆粒，他們認(rèn)為這可能是由于CMC作為一種自由基清除劑，清除了一部分活性氧，從而導(dǎo)致CMC-nZVI的毒性減弱，這也從側(cè)面證實氧化損傷是nZVI的毒性機(jī)制之一[62]。

2.3 鐵離子的釋放

金屬納米顆粒在溶液中具有一定的溶解性，可以溶出一定量的金屬離子[63]，同時在反應(yīng)(1)中，nZVI誘導(dǎo)產(chǎn)生活性氧的過程中也伴隨著鐵離子的釋放，因此鐵離子的釋放也可能是nZVI導(dǎo)致毒性效應(yīng)的原因。微量的鐵離子是生物體生長所必需的[64]，然而當(dāng)其含量過高時卻會對生物體造成嚴(yán)重的損害，或是參與Fenton反應(yīng)生成高反應(yīng)活性的自由基，造成機(jī)體氧化損傷[65-66]。Kim[67]等人證實nZVI釋放出的鐵離子是其導(dǎo)致MS2病毒失活的一個重要原因；Chen等人分別研究了CMC(carboxymethyl cellulose，羧甲基纖維素)-nZVI，nZVI以及Fe2+溶液對青鳉魚的影響，結(jié)果表明能夠釋放更多的鐵離子是CMC-nZVI毒性強于nZVI的一個重要因素[36]；EI-Temsah也認(rèn)為nZVI的毒性可能是間接的，是由釋放的鐵離子引起的[40]。Qiu[68]等人認(rèn)為nZVI的毒性會隨時間的推移而不斷減弱，暫時的毒性主要還是由于釋放的鐵離子造成。nZVI的毒性很有可能是納米顆粒本身與釋放出來的鐵離子共同作用的結(jié)果。

2.4 基因損傷

納米顆粒造成的基因損傷是目前大家關(guān)注的一個熱點，納米顆粒進(jìn)入細(xì)胞后可能直接攻擊DNA，使得DNA鏈斷裂[69]，也可能誘導(dǎo)產(chǎn)生大量活性氧，進(jìn)而與細(xì)胞核中的DNA發(fā)生反應(yīng)造成基因損傷[70]。研究nZVI與DNA的相互作用，將有助于人們從基因?qū)用嫔险J(rèn)識nZVI的致毒機(jī)理，從而更好地了解和評價nZVI的毒性影響，然而目前nZVI導(dǎo)致基因損傷的資料還比較少，這也是以后各國學(xué)者需要努力的一個方向。Kadar等人通過實驗研究nZVI對紫貽貝精子的影響，流式細(xì)胞術(shù)顯示nZVI可以導(dǎo)致精子死亡，而彗星實驗則證實較高濃度的nZVI造成了嚴(yán)重的DNA損傷[71]，nZVI導(dǎo)致的基因損傷很有可能是由氧化脅迫引起的，然而由于目前關(guān)于nZVI造成基因損傷的具體機(jī)制尚不明確，因此無從判斷這一機(jī)制是nZVI特有的，還是納米顆粒普遍存在的。

一種污染物的毒性機(jī)制往往不是單一的，可能是由多種因素共同導(dǎo)致的，對此應(yīng)該綜合考慮。如在反應(yīng)(1)中，既有鐵離子的釋放又伴隨著活性氧的產(chǎn)生，活性氧又可能會導(dǎo)致脂質(zhì)過氧化，影響細(xì)胞膜的通透性，使細(xì)胞功能受損，還有可能導(dǎo)致DNA的損傷[72]。為了明確nZVI的毒性機(jī)制，還需要更多的研究。

3 nZVI毒性效應(yīng)的影響因素

nZVI的毒性效應(yīng)會受到多種因素的影響，歸納起來主要有以下兩大類：一是nZVI的性質(zhì)(粒徑、表面特性等)，二是環(huán)境因素(溶解氧、培養(yǎng)介質(zhì)、有機(jī)質(zhì)等)，此外還與暴露的濃度、時間以及暴露方式有關(guān)。

nZVI的毒性效應(yīng)首先是由nZVI本身的性質(zhì)決定的。粒徑較小的納米顆粒更加容易進(jìn)入生物體內(nèi)，并且難以被巨噬細(xì)胞清除，可能會導(dǎo)致更強的生物毒性[73-74]，nZVI的粒徑大小是影響其毒性的關(guān)鍵因素之一。nZVI的表面特性對其毒性效應(yīng)也有一定的影響，由于nZVI較強的團(tuán)聚性能，并且很容易被氧化，因此在實際應(yīng)用過程中往往會對其表面進(jìn)行功能化修飾，這將會顯著改變nZVI的表面特性，從而有可能會改變其毒性效應(yīng)。王菁姣[75]等人研究了不同類型nZVI對大腸桿菌的毒性效應(yīng)，發(fā)現(xiàn)包覆型和負(fù)載型的nZVI毒性要明顯弱于未經(jīng)改性的。Phenrat[76]等研究了裸露nZVI和聚天冬氨酸改性后nZVI的神經(jīng)毒性效應(yīng)，結(jié)果表明不管是對哪種神經(jīng)細(xì)胞，改性后nZVI的毒性都要小于未經(jīng)改性的；Li等研究了nZVI對大腸桿菌的毒性效應(yīng)，也得出了類似的結(jié)論[77]，這可能是由于改性劑阻礙了nZVI和受試細(xì)胞的接觸，從而導(dǎo)致其毒性減弱。然而Chen[17]等在研究CMC改性以及未經(jīng)改性nZVI對青鳉魚的毒性時，則發(fā)現(xiàn)CMC-nZVI由于誘導(dǎo)產(chǎn)生更多的活性氧以及鐵離子，其毒性要強于未經(jīng)改性的nZVI。可見，目前nZVI改性對其毒性效應(yīng)的影響還沒有定論，這可能與不同受試生物有關(guān)，也可能受改性劑及改性方法的影響。此外有研究表明納米材料的毒性效應(yīng)還與顆粒本身的形狀以及表面電荷等有關(guān)[78]，然而目前還未見到nZVI毒性是否與之相關(guān)的類似報道。

nZVI在環(huán)境修復(fù)過程中被注射到污染位點，客觀存在的環(huán)境因素能夠改變其在環(huán)境中的理化行為，從而有可能會對nZVI的毒性效應(yīng)產(chǎn)生一定的影響。Chen[79]等人研究了nZVI對革蘭氏陰性大腸桿菌以及革蘭氏陽性枯草芽孢桿菌的毒性效應(yīng)，結(jié)果發(fā)現(xiàn)當(dāng)加入一種天然有機(jī)質(zhì)(薩旺尼河腐殖酸)后其毒性顯著降低，TEM(Transmission Electron Microscope，透射電鏡)圖顯示加入有機(jī)質(zhì)之后的nZVI顆粒周圍有可見的絨毛，阻礙了與大腸桿菌的接觸。Lee[46]等分別研究了有氧和無氧條件下nZVI對大腸桿菌的影響，發(fā)現(xiàn)在有氧條件下需要更高濃度的nZVI才能導(dǎo)致跟無氧條件下相同的致死率，表明在有氧條件下由于nZVI的腐蝕以及表面被氧化，毒性效應(yīng)會降低。Temsah[38]在溶液、沙土以及粘土條件下分別研究了nZVI對黑麥草、大麥以及亞麻種子萌發(fā)率的影響，結(jié)果表明在溶液中nZVI對種子萌發(fā)率的影響最大，沙土次之，而粘土條件下的影響最小，可能是由于土壤中有機(jī)質(zhì)和nZVI的相互作用，降低了nZVI的生物可利用性。Saccà[80]等人的研究結(jié)果也表明nZVI對土壤微生物的毒性作用與土壤的性質(zhì)有關(guān)。培養(yǎng)介質(zhì)和有機(jī)質(zhì)可能會對納米顆粒具有一定的吸附效果，從而對納米材料的毒性造成一定的影響，而溶解氧對nZVI毒性效應(yīng)的影響可能是特有的，目前尚未見著溶解氧對其他納米材料毒性影響的報道。不僅如此，由于nZVI的比表面積較大，對環(huán)境中各種有毒有害物質(zhì)有較強的吸附能力，其毒性可能不只是來自nZVI本身，還有可能來自它與環(huán)境污染物組成的復(fù)合體系，例如Fang等人就指出nZVI顆粒對多環(huán)芳烴具有較強的吸附能力[81]。此外nZVI的溶解性也會受到環(huán)境因素的影響(如水環(huán)境中的pH，水溫等)，進(jìn)一步會影響nZVI對鐵離子的釋放，從而可能也會對nZVI的毒性產(chǎn)生影響。因此，nZVI毒性的評價必須要綜合考慮環(huán)境因素對其物理化學(xué)行為的影響。

nZVI是一種新興的環(huán)境修復(fù)材料，在實際應(yīng)用過程中還有很多的不確定性，目前nZVI的生物安全性研究已經(jīng)引起了世界各國學(xué)者的廣泛關(guān)注，研究雖然剛起步，但是近年來迅速發(fā)展，然而由于其毒性的機(jī)制以及影響因素都比較復(fù)雜，技術(shù)和手段上也存在諸多限制，目前的研究結(jié)果還非常有限，并且差異較大，無法進(jìn)行對比分析，關(guān)于其環(huán)境行為、毒性機(jī)制以及生物可利用性等我們還知之甚少，今后可以從以下幾個方面加強相關(guān)研究：

(1) nZVI在實際環(huán)境中的行為。 目前的研究多局限在實驗室條件下，很多參數(shù)都是人為設(shè)定的，而實際環(huán)境條件要復(fù)雜的多，nZVI在環(huán)境中的物理、化學(xué)、生物轉(zhuǎn)化等都可能會對其存在形態(tài)、可利用性及毒性造成影響；

(2) nZVI的毒性機(jī)制。已有氧化損傷、有毒離子釋放等報道，然而對其確切的毒性機(jī)制還不清楚，在nZVI的跨膜機(jī)制以及進(jìn)入細(xì)胞后的存在形態(tài)、nZVI的生物可利用性等方面的研究還很匱乏；

(3) nZVI在其他物質(zhì)存在條件下的聯(lián)合毒性。 nZVI在合成過程以及實際修復(fù)過程中會使用各種分散劑和表面活性劑等，它們有發(fā)生聯(lián)合暴露的可能，這應(yīng)該是今后研究的一個重點；

(4) nZVI毒性評價方法以及評價終點的標(biāo)準(zhǔn)化。 從nZVI的合成到評價方法、評價終點的選擇上都應(yīng)該有規(guī)范的標(biāo)準(zhǔn)，納米顆粒不同于溶液狀態(tài)的毒物，在介質(zhì)中分布不均勻也是當(dāng)前研究遇到比較棘手的問題，應(yīng)該建立一套快速可行便于操作的標(biāo)準(zhǔn)方法。

[1] Li A, Tai C, Zhao Z, et al. Debromination of decabrominated diphenyl ether by resin-bound iron nanoparticles [J]. Environmental Science & Technology, 2007, 41(19): 6841-6846

[2] Zhang W X. Nanoscale iron particles for environmental remediation: An overview [J]. Journal of Nanoparticle Research, 2003, 5(3-4): 323-332

[3] Liu Y, Majetich S A, Tilton R D, et al. TCE dechlorination rates, pathways, and efficiency of nanoscale iron particles with different properties [J]. Environmental Science & Technology, 2005, 39(5): 1338-1345

[4] Kanel S R, Greneche J M, Choi H. Arsenic(V) removal from groundwater using nano scale zero-valent iron as a colloidal reactive material [J]. Environmental Science & Technology, 2006, 40(6) : 2045-2050

[5] Hoch L B, Mack E J, Hydutsky B W, et al. Carbothermal synthesis of carbon-supported nanoscale zero-valent iron particles for the remediation of hexavalent chromium [J]. Environmental Science & Technology, 2008, 42(7): 2600-2605

[6] Song H, Carraway E R. Reduction of chlorinated ethanes by nanosized zero-valent iron: kinetics, pathways, and effects of reaction conditions [J]. Environmental Science & Technology, 2005, 39(16): 6237-6245

[7] Wu D, Shen Y, Ding A, et al. Effects of nanoscale zero-valent iron particles on biological nitrogen and phosphorus removal and microorganisms in activated sludge [J]. Journal of Hazardous Materials, 2013, 262(12): 649-655

[8] Zhang X, Lin Y, Shan X, et al. Degradation of 2,4,6-trinitrotoluene (TNT) from explosive wastewater using nanoscale zero-valent iron [J]. Chemical Engineering Journal, 2010, 158(3): 566-570

[9] Shih Y, Hsu C, Su Y. Reduction of hexachlorobenzene by nanoscale zero-valent iron: Kinetics, pH effect, and degradation mechanism [J]. Separation and Purification Technology, 2011, 76(3): 268-274

[10] Machado S, Stawiński W, Slonina P, et al. Application of green zero-valent iron nanoparticles to the remediation of soils contaminated with ibuprofen [J]. Science of the Total Environment, 2013, 461(12): 323-329

[11] Singh S P, Bose P, Guha S, et al. Impact of addition of amendments on the degradation of DDT and its residues partitioned on soil [J]. Chemosphere, 2013, 92(7): 811-820

[12] Lundin L,Moltó J, Fullana A. Low temperature thermal degradation of PCDD/Fs in soil using nanosized particles of zerovalent iron and CaO [J]. Chemosphere, 2013, 91(6): 740-744

[13] Karn B, Kuiken T, Otto M. Nanotechnology and in situ remediation: A review of the benefits and potential risks [J]. Environmental Health Perspectives, 2009, 117(12): 1823-1831

[14] Yan W, Lien H L, Koel B E, et al. Iron nanoparticles for environmental clean-up: recent developments and future outlook [J]. Environmental Science: Processes & Impacts, 2013, 15(1): 63-77

[15] Mueller N C, Braun J, Bruns J, et al. Application of nanoscale zero valent iron (NZVI) for groundwater remediation in Europe [J]. Environmental Science and Pollution Research, 2012, 19(2): 550-558

[16] 朱慧杰, 賈永鋒, 吳星, 等. 負(fù)載型納米鐵吸附劑去除飲用水中As(III)的研究[J]. 環(huán)境科學(xué), 2009, 30(6): 1644-1648

Zhu H, Jia Y, Wu X, et al. Removal of arsenite from drinking water by activated carbon supported nano zero-valent iron [J]. Environmental Science,2009, 30(6): 1644-1648 (in Chinese)

[17] 席洪波, 廖娣劼, 尚海濤, 等. 納米鐵除磷的影響因素及吸附模式研究[J]. 給水排水, 2008, 34: 191-195

Xi H, Liao D, Shang H, et al. Influencing factors and adsorption model of phosphate removal by nanoscale iron [J]. Water & Wastewater Engineering,2008, 34: 191-195 (in Chinese)

[18] Crane R A, Scott T B. Nanoscale zero-valent iron: Future prospects for an emerging water treatment technology [J]. Journal of Hazardous materials, 2012, 211: 112-125

[19] Service R F. Nanomaterials show signs of toxicity [J]. Science, 2003, 300(11): 243

[20] Nel A, Xia T, Madler L. Toxic potential of materials at the nanolevel [J]. Science, 2006, 311(5761): 622-627

[21] Maynard A, Aitken R J, Butz T, et al. Safe handling of nanotechnology [J]. Nature, 2006, 444(7117): 267-269

[22] Auffan M, Rose J, Bottero J Y, et al. Towards a definition of inorganic nanoparticles from an environmental, health and safety perpective [J]. Nature Nanotechnology, 2009, 4(10): 634-641

[23] Stone V, Donaldson K. Nanotoxicology: Signs of stress [J]. Nature Nanotechnology, 2006, 1(1): 23-24

[24] Wiesner M R, Lowry G V, Alvarez P J J, et al. Assessing the risks of manufactured nanomaterials [J]. Environmental Science & Technology, 2006, 40(14): 4336-4345

[25] Kirschling T L, Gregory K B, Minkley, Jr E G, et al. Impact of nanoscale zero valent iron on geochemistry and microbial populations in trichloroethylene contaminated aquifer materials [J]. Environmental Science & Technology, 2010, 44(9): 3474-3480

[26] Kahru A, Dubourguier H C. From ecotoxicology to nano ecotoxicology [J]. Toxicology, 2010, 269(2-3): 105-119

[27] Savolainen K, Alenius H, Norppa H, et al. Risk assessment of engineered nanomaterials and nanotechnologies-a review [J]. Toxicology, 2010, 269(2): 92-104

[28] Boczkowski J, Hoet P. What’s new in nanotoxicology? Implications for public health from a brief review of the 2008 literature [J]. Nanotoxicology, 2010, 4(1): 1-14

[29] 王天成, 賈光, 沈惠麒, 等. 納米鐵材料對小鼠血清生化指標(biāo)的影響[J]. 環(huán)境與職業(yè)醫(yī)學(xué), 2004, 21(6): 434-436

Wang T, Jia G, Shen H, et al. Effect of excess iron nano-particles on serum biochemical indexes in mice [J]. Journal of Environmental & Occupational Medicine, 2004, 21(6): 434-436

[30] 王天成, 賈光, 王翔, 等. 納米鐵, 納米氧化鋅和納米氧化鎂對小鼠血清乳酸脫氫酶和 α-羥丁酸脫氫酶活性的影響[J]. 實用預(yù)防醫(yī)學(xué), 2006, 13(5): 1101-1102

Wang T, Jia G, Wang X, et al. Effect of nano-particle iron, zinc oxide and magnesia on serum LDH and HBDH activities in mice [J]. Practical Preventive Medicine,2006, 13(5): 1101-1102

[31] 王天成, 賈光, 王翔, 等. 納米鐵粉對小鼠血糖和血脂的影響[J]. 現(xiàn)代預(yù)防醫(yī)學(xué), 2007, 34(1): 7-8

Wang T, Jia G, Wang X, et al. The effect of excess nano-size iron powder on serum glucose and lipids in mice [J]. Modern Preventive Medicine, 2007, 34(1): 7-8

[32] 丁峰, 宋文華, 白茹, 等. 納米鐵材料對小鼠肺灌洗液中白細(xì)胞和羥脯氨酸的影響[J]. 南開大學(xué)學(xué)報: 自然科學(xué)版, 2008, 41(3): 1-4

Ding F, Song W, Bai R, et al. Effect of nanosized iron on leukocyte and hydroxyproline in bronchoalveolar of mice [J]. Acta Scientiarum Naturalium Universitatis Nankaiiensis, 2008, 41(3): 1-4

[33] Zhou Y, Zhong C, Kennedy I M, et al. Pulmonary responses of acute exposure to ultrafine iron particles in healthy adult rats [J]. Environmental Toxicology, 2003, 18(4): 227-235

[34] Li H, Zhou Q, Wu Y, et al. Effects of waterborne nano-iron on medaka (Oryzias latipes): Antioxidant enzymatic activity, lipid peroxidation and histopathology [J]. Ecotoxicology and Envirnmental Safety, 2009, 72(3) : 684-692

[35] Chen P J, Su C H, Tseng C Y, et al. Toxicity assessments of nanoscale zerovalent iron and its oxidation products in medaka (Oryzias latipes) fish [J]. Marine Pollution Bulletin, 2011, 63(5-12): 339-346

[36] Chen P J, Tan S W, Wu W L, et al. Stabilization or oxidation of nanoscale zerovalent iron at environmentally relevant exposure changes bioavailability and toxicity in msdaka fish [J]. Environmental Science & Technology, 2012, 46(15): 8431-8439

[37] Chen P J, Wu W L, Wu C W. The zerovalent iron nanoparticle causes higher developmental toxicity than its oxidation productsin early life stages of medaka fish [J]. Water Reaseach, 2013, 47: 3899-3909

[38] EI-Temsah Y S, Joner E J. Impact of the Fe and Ag nanoparticles on seed germination and differences in bioavailability during exposure in aqueous suspension and soil [J]. Environmental Toxicology, 2012, 27(1): 42-49

[39] Ma X, Gurung A, Deng Y. Phytotoxicity and uptake of nanoscale zero-valent iron (nZVI) by two plant species [J]. Science of the Total Environment, 2013, 443: 844-849

[40] EI-Temsah Y S, Joner E J. Ecotoxicological effects on earthworms of fresh and aged nano-sized zero-valent iron (nZVI) in soil [J]. Chemosphere, 2012, 86(1): 76-82

[41] EI-Temsah Y S, Joner E J. Effects of nano-sized zero-valent iron (nZVI) on DDT degradation in soil and its toxicity to Collembola and Ostracods [J]. Chemosphere, 2013, 92: 131-137

[42] Marsalek B, Jancula D, Marsalkova E, et al. Multimodal action and selective toxicity of zerovalent iron nanoparticles against Cyanobacteria [J]. Environmental Science & Technology, 2012, 46(4): 2316-2323

[43] Diao M, Yao M. Use of zero-valent iron nanoparticles in inactivating microbes [J]. Water Research, 2009, 43(20): 5243-5251

[44] Barnes R J, Riba O, Gardner M N, et al. Inhibition of biological TCE and sulphate reduction in the presence of nanoparticles [J]. Chemosphere, 2010, 80(5): 554-562

[45] Xiu Z, Jin Z, Li T, et al. Effects of nano-scale zero-valent iron particles on a mixed culture dechlorinating trichloroethylene [J]. Bioresource Technology, 2010, 101(4): 1141-1146

[46] Lee C, Kin J Y, Lee W I, et al. Bactericidal effect of zero-valent iron nanoparticles on Escherichia coli [J]. Environmental Science & Technology, 2008, 42(13): 4927-4933

[47] Auffan M, Achouak W, Rose J, et al. Relation between the redox state of iron-based nanoparticles and their cytotoxicity toward Escheriachia coli [J]. Environmental Science & Technology, 2008, 42(17): 6730-6735

[48] 王學(xué), 李勇超, 李鐵龍, 等. 零價納米鐵對大腸桿菌的毒性效應(yīng)[J]. 生態(tài)毒理學(xué)報, 2012, 7(1): 49-56

Wang X, Li Y, Li T, et al. Toxicity effect of nano-Fe0on Escherichia coli [J]. Asian Journal of Ecotoxicity, 2012, 7(1): 49-56

[49] You Y, Han J, Chiu P C, et al. Removal and inactivation of waterborne viruses using zerovalent iron [J]. Environmental Science & Technology, 2005, 39(23): 9263-9269

[50] Cullen L G, Tilston E L, Mitchell G R, et al. Assessing the impact of nano- and micro-scale zerovalent iron particles on soil microbial activities: Particle reactivity interferes with assay conditions and interpretation of genuine microbial effects [J]. Chemosphere, 2011, 82(11): 1675-1682

[51] Tilston E L, Collins C D, Mitchell G R, et al. Nanoscale zerovalent iron alters soil bacterial community structure and inhibits chloroaromatic biodegradation potential in Aroclor 1242-contaminated soil [J]. Environmental Pollution, 2013, 173: 38-46

[52] Fajardo C, Ortiz L T, Rodriguez-Membibre M L, et al. Assessing the impact of zero-valent iron (ZVI) nanotechnology on soil microbial structure and functionality: A molecular approach [J]. Chemosphere, 2012, 86(8): 802-808

[53] Barnes R J, van der Gast C J, Riba O, et al. The impact of zero-valent iron nanoparticles on a river water bacterial community [J]. Journal of Hazardous Materials, 2010, 18(1): 73-80

[54] Pawlett M, Ritz K, Dorey R A, et al. The impact of zero-valent iron nanoparticles upon soil microbial communities is context dependent [J]. Environmental Science and Pollution Research, 2013, 20(2): 1041-1049

[55] Verma A, Uzun O, Hu Y, et al. Surface-structure-regulated cell-membrane penetration by monolayer-protected nanoparticles [J]. Nature Material, 2008, 7(7): 588-595

[56] Navarro E, Baun A, Behra, R, et al. Environmental behavior and ecotoxicity of engineered nanoparticles to algae, plants, and fungi [J]. Ecotoxicology, 2008, 17(5): 372-386

[57] Keenan C R, Sedlak D L. Factors affecting the yield of oxidants from the reaction of nanoparticulate zero-valent iron and oxygen [J]. Environmental Science & Technology, 2008,42(4): 1262-1267

[58] Joo S H, Feitz A J, Sedlak D L, et al. Quantification of the oxidizing capacity of nanoparticulate zero-valent iron [J]. Environmental Science & Technology, 2005, 39(5): 1263-1268

[59] Van der Oost R, Beyer J, Vermeulen N P E. Fish bioaccumulation and biomarkers in environmental risk assessment: a review [J]. Environmental Toxicology and Pharmacology, 2003, 13(2): 57-149

[60] Xia T, Kovochich M, Liong M. Cationic polystyrene nanosphere toxicity depends on cell-specific endocytic and mitochondrial injury pathways [J]. ACS Nano, 2008, 2(1): 85-96

[61] Keenan C R, Goth-Goldstein R, Lucas Donald, et al. Oxidative stress induced by zero-valent iron nanoparticles and Fe(II) in human bronchial epithelial cells [J]. Environmental Science & Technology, 2009, 43(12): 4555-4560

[62] Zhou L, Thanh T L, Gong J, et al. Carboxymethyl cellulose coating decreases toxicity and oxidizing capacity of nanoscale zerovalent iron [J]. Chemosphere, 2014, 104, 155-161

[63] 王震宇, 趙建, 李娜, 等. 人工納米顆粒對水生生物的毒性效應(yīng)及其機(jī)制研究進(jìn)展[J]. 環(huán)境科學(xué), 2010, 31(6): 1409-1418

Wang Z, Zhao J, Li N, et al. Review of ecotoxicity and mechanism of engineered nanoparticles to aquatic organisms [J]. Environmental Sciences, 2010, 31(6): 1409-1418 (in Chinese)

[64] 徐金, 劉紹明. 鐵離子對大腦毒性的研究進(jìn)展[J]. 醫(yī)學(xué)綜述, 2012, 18(15): 2383-2385

Xu J, Liu S. Research progress of toxicity of iron ion to brain [J]. Medical Recapitulate, 2012, 18(15): 2383-2385 (in Chinese)

[65] Valko M, Morris H, Cronin M T. Metals, toxicity and oxidative stress [J]. Current Medicinal Chemistry, 2005, 12(10): 1161-1208

[67] Kim J Y, Lee C, Love D C, et al. Inactivation of MS2 coliphage by ferrous ion and zero-valent iron nanoparticles [J]. Environmental Science & Technology, 2011, 45(16): 6978-6984

[68] Qiu X, Fang Z, Yan X, et al. Chemical stability and toxicity of nanoscale zero-valent iron in the remediation of chromium-contaminated watershed [J]. Chemical Engineering Journal, 2013, 220: 61-66

[69] Singh N, Manshian B, Jenkins G, et al. Nanogenotoxicology: the DNA damaging potential of engineered nanomaterials [J]. Biomaterials, 2009, 30(23-24): 3891-3914

[70] Xia T, Kovochich M, Brant J, et al. Comparison of the abilities of ambient and manufactured nanoparticles to induce cellular toxicity according to an oxidative stress paradigm [J]. Nano Letters, 2006, 6(8): 1794-1807

[71] Kadar E, Tarran G A, Jha A N, et al. Stabilization of engineered zero-valent nanoiron with Na-Acrylic copolymer enhances spermiotoxicity [J]. Environmental Science & Technology, 2011, 45(8): 3245-3251

[72] Kahru A, Dubourguier H, Blinova I, et al. Biotests and biosensors for ecotoxicology of metal oxide nanoparticles: A minireview [J]. Sensors, 2008, 8(8): 5153-5170

[73] Choi O, Hu Z. Size dependent and reactive oxygen species related nanosilver toxicity to nitrifying bacteria [J]. Environmental Science & Technology, 2008, 42(12): 4583-4588

[74] Hund-Rinke K, Simon M. Ecotoxic effect of photocatalytic active nanoparticles TiO2on algae and daphnids [J]. Environmental Science and Pollution Research, 2006, 13(4): 225-232

[75] 王菁姣, 陳家瑋. 不同種類納米零價鐵的毒性比較研究[J]. 現(xiàn)代地質(zhì), 2012,26(5): 926-931

Wang J, Chen J. Comparison study on toxicity of different nanoscale zero-valent iron [J]. Geoscience,2012, 26(5): 926-931 (in Chinese)

[76] Phenrat T, Long T C, Lowery G V, et al. Partial oxidation and surface modification decrease the toxicity of nanosized zerovalent iron [J]. Environmental Science & Technology, 2008, 43(1): 195-200

[77] Li Z, Greden K, Alvarez P J J, et al. Adsorbed polymer and NOM limits adhesion and toxicity of nano scale zerovalent iron to E. coli [J]. Environmental Science & Technology, 2010, 44(9): 3426-3467

[78] Handy R D, Von der Kammer F, Lead J R, et al. The ecotoxicology and chemistry of manufactured nanoparticles [J]. Ecotoxicology, 2008, 17(4): 287-314

[79] Chen J, Xiu Z, Lowery G V, et al. Effect of natural organic matter on toxicity and reactivity of nano-cale zero-alent iron [J]. Water Research, 2011, 45(5): 1995-2001

[80] Saccà M L, Fajardo C, Costa G, et al. Integrating classical and molecular approaches to evaluate the impact of nanosized zero-valent iron (nZVI) on soil organisms [J]. Chemosphere, 2014, 104, 184-189

[81] Fang J, Shan X, Wen B, et al. Sorption and desorption of phenanthrene onto iron, copper, and silicon dioxide nanoparticles [J]. Langmuir, 2008, 24(19): 10929-10935

◆

Review of the Ecotoxicity of Nanoscale Zero-valent Iron

Ge Xingbin1, Wang Zhenhong1, Guo Chuqi2, Sun Xin1, Li Tielong1,*，Wang Wei1

1. College of Environmental Science and Engineering, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Biomass Solid Waste Reclamation Technology & Engineering Center, Nankai University, Tianjin 300071, China 2. College of Environmental Science and Safety Engineering,Tianjin University of Technology, Tianjin 300191, China

Received 27 February 2014 accepted 5 July 2014

As an efficient environmental remediation material, nanoscale zero-valent iron (nZVI) has been broadly applied in the remediation of contaminatedgroundwater and soil for its huge specific surface area, high surface reactivity and strong reducibility. However, the injection of large amount of iron nanoparticles into the contaminated sites should increase its exposure possibility to ecosystem, and thus pose potential risk to environment and ecosystem, since it can pass through the cell membrane and the protective screens of organisms resulting from its extremely small particle size. Considering both the broad potential application of nZVI in environmental remediation and its possible toxicity, it is of great importance to investigate the environmental risk of nZVI, and more attention has been paid to the biological safety of nZVI. This paper overviews the research progress on the toxicity effect of iron nanoparticle in these years. NZVI could lead to negative effects on viruses, bacteria, microbial communities, as well as animals and plants. Although the toxicity mechanisms of nZVI remain unclear, a general viewpoint suggests that the toxicity effect should be resulted from the release of iron ions and the following oxidative damage. The effect of environmental factors and surface modification on the toxicity of nZVI is also discussed. In addition, prospect of the development of nZVI is presented to provide some reference for the research on the nZVI in the future.

NZVI; ecotoxicity; oxidative damage; mechanisms of toxicity; influence factors

2014-02-27 錄用日期：2014-07-05

1673-5897(2015)3-028-10

X171.5

A

李鐵龍(1977—)，男，環(huán)境科學(xué)博士，副教授，主要研究方向為環(huán)境污染與防治，發(fā)表學(xué)術(shù)論文80余篇。