Effect of climate change on humic substances and associated impacts on the quality of surface water and groundwater: A review

2018·1.1 MB·English

by  Ewa Lipczynska-Kochany

ScienceoftheTotalEnvironment640–641(2018)1548–1565
ContentslistsavailableatScienceDirect
Science of the Total Environment
journal homepage: www.elsevier.com/locate/scitotenv
Review
Effect of climate change on humic substances and associated impacts on
the quality of surface water and groundwater: A review
EwaLipczynska-Kochany
EnvironmentalConsultants,Mississauga,ONL5A4C3,Canada
H I G H L I G H T S G R A P H I C A L A B S T R A C T
(cid:129) Humicsubstances(HS)playanimpor-
tantroleingenerationofgreenhouse
gases(GHG).
(cid:129) Climatechange(CC)enhancesbiodeg-
radationofhumicsubstances(HS).
(cid:129) Microbialactivityisstimulatedanddeg-
radationofcontaminantsmoreefficient.
(cid:129) Solardisinfectioninsurfacewatersis
inhibitedbyincreasedpresenceofDOM.
(cid:129) Pollutants may be desorbed and re-
mobilized.
a r t i c l e i n f o a b s t r a c t
Articlehistory: Humicsubstances(HS),ahighlytransformedpartofnon-livingnaturalorganicmatter(NOM),compriseupto
Received31October2017 70%ofthesoilorganicmatter(SOM),50–80%ofdissolvedorganicmatter(DOM)insurfacewater,and25%of
Receivedinrevisedform30May2018 DOMingroundwater.Theyconsiderablycontributetoclimatechange(CC)bygeneratinggreenhousegases
Accepted30May2018
(GHG).Ontheotherhand,CCaffectsHS,theirstructureandreactivity.HSimportantroleinglobalwarming
Availableonline18June2018
hasbeenrecognizedandextensivelystudied.However,muchlessattentionhasbeenpaidsofartoeffectson
thefreshwaterquality,whichmayresultfromtheclimateinducedimpactonHS,andHSinteractionswithcon-
Editor:D.Barcelo
taminantsinsoil,surfacewaterandgroundwater.Itisexpectedthatanincreasedtemperatureandenhancedbio-
Keywords: degradationofSOMwillleadtoanincreaseintheproductionofDOM,whilethefloodingandrunoffwillexportit
Climatechange fromsoiltorivers,lakes,andgroundwater.Microbialgrowthwillbestimulatedandbiodegradationofpollutants
Humicsubstances inwatercanbeenhanced.However,theremaybealsonegativeeffects,includinganinhibitionofsolardisinfec-
Surfacefreshwater tioninbrownlakes.TheCCinduceddesorptionfromsoilandsediments,aswellasre-mobilizationofmetalsand
Wetlands organicpollutantsareanticipated.In-situtreatmentofsurfacewaterandgroundwatermaybeaffected.Qualityof
Groundwater thesourcefreshwaterisexpectedtodeteriorateanddrinkingwaterproductionmaybecomemoreexpensive.
In-situremediation
ManyofthepossibleeffectsofCCdescribedinthisarticlehaveyettobeexploredandunderstood.Enormouspo-
tentialforinteresting,multidisciplinarystudiesintheimportantresearchareashasbeenpresented.
©2018ElsevierB.V.Allrightsreserved.
E-mailaddress:[email protected].
https://doi.org/10.1016/j.scitotenv.2018.05.376
0048-9697/©2018ElsevierB.V.Allrightsreserved.
E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565 1549
Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1549
2. Humicsubstances(HS)andtheirroleinCC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1549
2.1. HS:structureandreactivity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1549
2.2. HSroleinCC:generationofgreenhousegases(GHG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1550
3. EffectofCConsoilHS,theirbiodegradationandinteractionswithpollutants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1551
3.1. MicrobialdegradationofHS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1551
3.2. InteractionsbetweenHSandsoilcontaminants. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1552
4. EffectofCConthequalityofsurfacefreshwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1552
4.1. GlobalconsequencesofCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1552
4.2. InteractionsbetweenHSandmicrobesinfreshwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1552
4.3. HSandpollutantsinsurfacewaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1553
4.4. EffectofsunlightontheHS-microbialinteractionsinfreshwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1553
4.5. Surfacewaterremediationandproductionofdrinkingwater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1554
4.5.1. Surfacewaterpollution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1554
4.5.2. Naturalandconstructedwetlands(CWs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1554
4.5.3. Productionofdrinkingwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1554
5. EffectofCConthequalityofgroundwateranditsremediationin-situ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1555
5.1. EffectofCCongroundwaterrechargeandquality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1555
5.2. Groundwaterremediationin-situ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1556
6. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1557
7. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1557
Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1557
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1557
1.Introduction 2017;Morenoetal.,2017;Wangetal.,2017).Thesereportsindicatethat
theeffectsofsolar,geophysical,andhumanactivityonCCinteract,and
“Climate”termreferstoglobal,long-term(yearsordecades)environ- thatmoreinvestigationsarerequiredinordertoexplainthiscomplicated
mentalconditions,e.g.globalaverageoftemperature,humidityandrainfall relationship.Whateverthereason,naturaloranthropogenic,thereisa
patternsoverseasons.“Climatechange”termdescribesanychangeincli- largebodyofevidencethattheEarth'sclimateischanging(IPCC,2001;
mateconditionsresultingfromnaturalcausesorhumanactions.Itde- King,2004)andthatglobalwarmingisthemaincharacteristicofthis
scribesabroadrangeofglobalphenomena,whichincludetheincreased change(NASA,2016).
temperaturetrends(globalwarming)andotherchangeslikeriseinsea Humicsubstances(HS)considerablycontributetoglobalwarmingby
level;lossoficemassandextremeweatherevents(NASA,2018). generatingGHG.Theirroleintheglobalwarminghasbeenextensively
ChangesintheEarth'sclimatehavebeenhappeningsincetheEarth's studiedandreported(Section2.2below).Ontheotherhand,CCaffects
generation.Therehavebeensevencyclesofglacialeventsuntil,about HS,theirstructureandreactivity.Manytopics,includingtheeffectonthe
7000yearsago,thelasticeageendedandthemodernclimateeraand soilorganicmatter(SOM),itsstructure,microbialcommunityaswellas
humancivilizationbegan.Mostofthepastclimatechangesarebelieved carbonstorageandrespirationresponsearestillnotfullyunderstood
tohaveresultedfromverysmallvariationsintheEarth'sorbit,which (Bond-Lambertyetal.,2016).Muchlessattentionhasbeenpaidsofarto
changedtheamountofsolarenergyreceivedbyEarth(Lean,2010). freshwater(surfaceandgroundwater)pollution,resultingfromtheclimate
Sincetheearly20thcentury,especiallysincethelate1970s,anincreas- inducedimpactonHSandtheirinteractionswithsoilandwaterpollutants.
ingtemperaturetrendacrossthewholeEarth,namedastheglobal ThisarticlestartswithpresentationofHS,theirstructure,reactivityand
warming, has been observed (NASA, 2018). It has been concluded contributiontothegenerationofGHG.Subsequently,potentialimpactsof
that,contrarytothepastclimatechanges,Sunisnotresponsiblefor CContheHSbiodegradation,microbialactivityinsoilandwateraswell
the increase in the Earth's temperature observed over the past asfreshwaterpollutionarereviewed.Theeffectsincludeaninhibitionof
50years.Instead,recentchangesintheEarthclimatearerelatedto solardisinfectioninbrownlakescausedbyanincreasedconcentrationof
humanactivityandhuman-producedgreenhousegases,GHG(IPCC, NOM,resultingfromtheenhanceddegradationofHSandsubsequent
2014;Lockwood,2009;NASA,2018;Oreskes,2004). wash-upfromthesoilandsedimentsurfaces.TheCCinduceddesorption
Most of GHG(CO , CH , N OandH O) occurnaturally. The heat- fromsoilandsediments,aswellasre-mobilizationofmetalsandorganic
2 4 2 2
trappingcapacityofthenaturallygeneratedGHGhasbeenknownfora pollutantshavebeenconsidered.PossibleCCeffectsontheprocessesrele-
longtime.ThereisancientevidenceshowingthattheEarth'sclimatere- vanttothein-situsurfacewaterandgroundwaterremediation,including
spondstochangesinGHGlevels.Forthousandsofyears,naturalsources constructedwetlands(CWs),in-situflushingandpermeablereactivebar-
ofGHGhavebeenbalancedbynaturalsinks.Humanactivitysignificantly riers(PRBs),havebeendiscussed.Thisreviewconcentratesontheimpact
contributestoemissionsofallknownGHGexceptfortheH Ovapor ofCConprocessesoccurringinnaturalenvironmentandonthequalityof
2
(Bousquetetal.,2006;IPCC,2014;USEPA,2016).Itisbelievednowthat freshwaterresources.However,anydeteriorationinthesourcefreshwater
humanactivityhasupsetthebalance,whichexistedbeforetheIndustrial qualitywillaffectthedrinkingwaterproduction.Therefore,CCeffectson
Revolution(IPCC,2001,NASA,2018;NASEM,2017a;USEPA,2017a,b). thedrinkingwatertreatmenthavebeenbrieflydescribed.
Resultsofthelateststudiesseemtocontradicttheconclusionthat
humanactivityistheonlycauseoftheobservedclimatechange.Ithas 2.Humicsubstances(HS)andtheirroleinCC
beenshownthatalargeproportionofclimatevariationscouldbeexplained
byactionoftotalsolarirradiance(TSI)andcosmicrays(CRs)onthestateof 2.1.HS:structureandreactivity
theloweratmosphereandothermeteorologicalparameters(Alexandri
etal.,2017;Biktash,2017;Chapanovetal.,2017;Friis-Christensenand HSarethemajorcarbonpoolinthebiosphere,about1600×1015gC.
Lassen,1991;EngelsandvanGeel,2012;KilifarskaandHaight,2005;Ma, Theycompriseupto70%ofsoilorganicmatter,SOM(Grinhutetal.,
1550 E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565
2007)andtheyrepresentabout50–80%ofdissolvedorganicmatter naturalsourcesofCH includewetlandsandoceans(USEPA,2017a)
4
(DOM)infreshwater(Thurman,1985),25%ofDOMingroundwater aswellaseruptionsofvolcanoes(Etiopeetal.,2007;NASEM,2017b).
andasmallfraction(0.7–2.4%)ofDOMinocean(Pauletal.,2004).HS SoilsundernaturalvegetationareanimportantsourceofN O,which
2
playaveryimportantroleinecosystemsbecausetheyregulatethe is also produced in oceans. H O vapor is the most abundant GHG.
2
globalcarbonandnitrogencycles.Theyarebrowntodarkcoloredmix- Large amounts of H O are released by volcanoes (LeGrande et al.,
2
tures,usuallyseparatedintothreefractionsbasedontheiraqueoussol- 2016;NASEM2017b;Robock,2000)andbyevaporationfromoceans,
ubility:fulvicacids,humicacids,andhumin.Accordingtothecurrent lakesandrivers.H Oactsasafeedbacktotheclimate.Itresponds
2
view(PiccoloandConte,2000;Piccolo,2001),HSshouldbeconsidered quicklytochangesinconditionsbyprecipitationasrainorsnow,or
assupramolecularassociationsofheterogeneousandrathersmallmol- evaporationbacktotheatmosphere(USEPA,2017a,b).
ecules.HSdynamicconformation isweaklystabilizedbyhydrogen ThereisevidencethatHSinsoilandwetlandssignificantlycontrib-
bondsandvanderWaalsinteractions;itcanbedisruptedbyweakor- utetoCCbyproducingGHG,includingCO (Fig.1).Approximately81%
2
ganic acids (Peuravuori, 2005; Peuravuori et al., 2007; Piccolo and oftheorganiccarbonresourcesisinvolvedinthesignificantdegrada-
Conte,2000;Piccolo,2001,2002). tion of SOM and it results in increased CO emissions from soils
2
HSstructuredependsontheiroriginandageandsoitisdifficultto (Dalias et al., 2001; Davidson and Janssens, 2006; Jenkinson et al.,
characterizeitonthemolecularlevel(Hedgesetal.,2000).However, 1991;Kattereretal.,1998;Kirschbaum,1995,2000,2006;Lloydand
manyHSpropertiesarewelldeterminedandsomecharacteristics,re- Taylor,1994;Trumboreetal.,1996).AccordingtoKirschbaum(1995),
gardlessoftheirorigin,aresimilar.HScontainvariousfunctionalgroups a1°Cincreaseoftemperaturewouldleadto10%carbonlossinareas
(Stevenson,1994)andformcomplexeswithmetalsandorganiccom- withmeantemperatureabout5°C,whereasthesametemperaturein-
pounds (Aiken et al., 2011; Davies et al., 1997; Nriagu and Coker, creasewouldleadtolossof3%inareaswheremeantemperatureis30
1980;PerminovaandHatfield,2005;SpositoandWeber,1986;Struyk °C.Therefore,importantregionaldifferencesintheSOMlossandCO
2
andSposito,2001).Theycontainhighamountsofstablefreeradicals productioncanbeexpected.Innaturalenvironments,carbonenters
(Pauletal.,2006a)whichcanreactwithvariousbioticandabioticsub- thesoilinlitterfall,rootturn-overordeathofindividualplants,provid-
stances.Theybehavelikecolloids(Piccoloetal.,1996;vonWandruszka, ingthesubstratefortheformationofSOM.TheamountofHSinSOMis
2000)andareknownforthesorptionabilities(Aeschbacheretal.,2012; controlledbytheHSproduction(inputofplantandanimaldebris)and
Georgietal.,2007,2008;Niedereretal.,2007).HSregulatethegrowth therateofthedegradation.Both,theSOMformationanddegradation,
ofplantsandmicroorganisms,actasbiostimulantsinhorticultureand aretemperature-dependent.Thechangeofthesoilcarbonstorageinre-
arethemajorcomponentoforganicfertilizers.HScatalyzebiochemical sponsetoclimatewarmingdependsonhowtheyarebalancedrelative
reactionsandhavedirectnutritivevalue,becausetheirlowmolecular toeachother(DavidsonandJanssens,2006;Kirschbaum,2000,2006;
partscanbetakenbyaquaticorganisms(Canellasetal.,2015;Piccolo, Stergiadietal.,2016;VonLützowandKögel-Knabner,2009).Degrada-
1996).Theyareinvolvedinenvironmentprocesses,includingredoxre- tionofDOMwithinlakesandriversmayalsoimpactclimateifDOMis
actions,sorption,complexation,fateandtransportofheavymetalsand completelymineralizedandemitsCO toatmosphere(Tranviketal.,
2
organicpollutants,aswellasthestabilizationofsoilstructure.Toxicity 2009;Raymondetal.,2013).
ofheavymetalstobacteriaisoftencorrelatedtothefreecationsconcen- Methane (CH ) is the GHG with the global warming potential
4
tration.FormationofHS–metalcomplexesandadsorptionofmetalcat- (GWP) 28–36times higher than CO on a 100 year time scale (US
2
ionsonthesurfaceofHS(andironoxyhydroxides)reducestoxicityof EPA,2017b).15–40%oftheglobalCH comesfromwetlands,wheremi-
4
heavymetalsbyloweringtheconcentrationoftheirfreecationsin crobialactivityisfundamentallydifferentfromthatinuplandecosys-
water (Davies et al., 1997; Nriagu and Coker, 1980; Sposito and tems(Yvon-Durocheretal.,2014).Wetlandscoverapproximately6%
Weber, 1986; Struyk and Sposito, 2001, Lipczynska-Kochany and oftheEarth'slandsurface.Theyaretransitionalareasbetweenland
Kochany,2009). and water with the not always well-defined boundaries (US EPA,
Theassociationorbindingofnon-polar,hydrophobicorganicmole- 2015).Theyrepresentabout12%oftheglobalcarbonpoolandthey
culestoHSincreasesthesolubilityandthusmobilityofvariouscontam- playanimportantroleintheglobalcarboncycle(IPCC,1996).Inaddi-
inants. On the other hand, interactions between HS and organic tiontoemissionofGHG,wetlandsalsoaffecttheclimatebyregulating
pollutantsmayresultinacompleteimmobilizationandincorporation airtemperaturethroughevapotranspiration(Pokornýetal.,2016).
ofsomesubstancesintoHS(BronnerandGoss,2011;Georgietal., Wetlandscanserveasboth,acarbonsinkandsource;theyactasa
2007,2008;Panetal.,2008;PolubesovaandChefetz,2014).Microbes long-termstorageofCO ,buttheyarealsoalargesourceofCH .In
2 4
maybealsoadsorbedonHS.Thus,HSmayaffectthebioavailabilityof mostuplandsoilsorganiccarboncanbecompletelymineralizedto
organiccontaminantstobacteriabybindingthemicrobesaswellas CO bymicroorganisms,usingoxygen(O )asaterminalelectronaccep-
2 2
the pollutants (Perminova and Hatfield, 2005; Van Trump et al., tor(TEA).Incontrast,anaerobicdecompositioninwetlandsoilinvolves
2006).HSalsoplayasignificantroleintheanaerobicbiologicalpro- manymicrobialprocessesgeneratingbothCO andCH asthefinal
2 4
cessesbyactingaselectrondonors,acceptorsandelectronshuttles.Bac- productsofmineralization(BartlettandHarris,1993;Caoetal.1998;
teria can use HS as an electron donor or acceptor in anaerobic FrolkingandRoulet2007;KellerandBridgham,2007;Kelleretal.,
respiration(Coatesetal.,2002;Heitmannetal.,2007;Lauetal.,2015; 2009;Yu,2012).Wetlands(andsediments)containahighcontentof
Lipczynska-Kochany,2018;Martinezetal.,2013;VanTrumpetal., HS,whichactaselectronacceptorsforanaerobicmicrobialrespiration,
2006).ElectrontransfertoandfromHSisfullyreversibleandsustain- includinganaerobicCH oxidation(BlodauandDeppe2012;Bridgham
4
ableoversuccessiveredoxcycles(Klüpfeletal.,2014;Walpenetal., etal.,2006,2013;Cervantesetal.,2000,2011;Coatesetal.,2002;Keller
2018). and Bridgham 2007; Keller and Takagi 2013; Lovley et al., 1996;
Lipczynska-Kochany,2018andrefs;Martinezetal.,2013;Valenzuela
2.2.HSroleinCC:generationofgreenhousegases(GHG) etal.,2017).Recently,Walpenetal.(2018)haveobservedthatthat
electrontransfertoDOMisfullyreversibleoveranelectrochemicalre-
MostGHG(CO ,CH ,N O,andH O)havebeengeneratedthrough ductionandsubsequentO -reoxidationcycle.Thisfindingsupportspre-
2 4 2 2 2
natural processes. For instance, CO emissions originate from an viousreports(Klüpfel et al., 2014)that HScanactasre-generable
2
ocean-atmosphereexchange,plantandanimalrespirationaswellas electronacceptors,allowingholdinglargeamountofCH inwetlands,
4
soilrespirationanddecomposition.CO isalsocreatedbyvolcanicerup- andnottoreleaseittotheatmosphere.
2
tionsandthroughundergroundvolcanicmagma.Itisreleasedthrough DOMcarboncyclinghasaninfluenceonclimatebecausedegrada-
vents,porousrocksandsoils,andwater,whichfeedsvolcaniclakesand tiontoCO andCH isoneofthemainsinksofDOMinboreallakes
2 4
hotsprings(LeGrandeetal.,2016;NASEM2017b;Robock,2000).The andwetlands.However,itsneteffectonglobalwarmingisdifficultto
E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565 1551
Fig.1.HSimpactonclimatechange(CC).
bepredicted(BertilssonandTranvik,2000).Forinstance,inplaceswhere N Oinsoilsaremicrobially-mediatedprocesses,nitrificationanddeni-
2
waterlevelsfallandorganicmatterisexposedtoair,moreCO canbere- trification.N Oemissionscanoccurasdirectemissionsfromnatural
2 2
leasedfromtheformerlyanoxicsedimentswhichproducedCH ,more and constructive wetlands (CWs) as well as from lakes and major
4
powerfulgreenhousegas(MortschandQuinn1996;Benoyetal.,2007). riversystems.DOMplaysanimportantroleindrivingmicrobially-
DependingonthebalancebetweenDOMlossestoatmosphereversus mediateddenitrification(PhilipandTownsend,2010).Recentstudies
transfertothesediments,formationofCO andCH andtheirsubsequent suggestthatsoilbiocharamendmentreducessoilnitrousoxide(N O)
2 4 2
releasetotheatmospherecanincreaseordecrease,affectingtheeffectof emissionsanditleadstoshiftsinthesoilmicrobialcommunitycompo-
climatechange.Complexmicrobialprocesses,whichplayanimportant sition(Harteretal.,2016;Jonesetal.,2014).
roleintheglobalfluxesofCO andCH,arelikelytobeaffectedbyCC.How-
2 4
ever,isstillunclear,whetheralterationoftheseprocessesmightresultina 3.EffectofCConsoilHS,theirbiodegradationandinteractionswith
netpositiveornegativefeedbackforGHGemissions(Singhetal.,2010).Itis pollutants
alsouncertainifwetlandsHSwillhaveapositiveornegativefeedbackto
theglobalclimatesystem(Frolkingetal.,2011;Junketal.,2013;Lenhart 3.1.MicrobialdegradationofHS
2009;Mengetal.,2012,2016).
Nitrousoxide,N2O,anotherpotentGHG,hasanatmosphericlifetime HScontributetochangeinclimatebygeneratingGHG.Ontheother
ofabout100years,andanalmost300-foldgreaterglobalwarmingpo- hand,CChasasignificantimpactontheHSstructureaswellasontheir
tential(GWP)comparedtoCO2(USEPA,2017b).Themainsourcesof bioticandabioticinteractions(Fig.2).
Fig.2.ImpactofCConHSinsoilandsediments.
1552 E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565
Innature,thehalf-decaytimes(t )ofHScanamounttothousands metals(Daviesetal.,1997;Dercovaetal.,2007Conteetal.,2005;
1/2
ofyears(Grinhutetal.,2007)andsoithasoftenbeenassumedthatHS PerminovaandHatfield,2005;Sanninoetal.,2013).Onecanexpect
areinerttobiodegradation.However,eventhoughHSbelongtothe thatCC,whichaltersthestructureandthereactivityofHS,wouldaffect
moststablecomponentsofthesoilorganicfraction,theirmicrobialde- theefficiencyofsuchtreatments.
compositionconstitutesasignificantpartoftheturnoveroforganiccar- Complicated interactions between soil HS, oxides and clays
boninsoil(Lipczynska-Kochany,2018;Martinezetal.,2013).Bacteria, (Vermeeretal.,1999)withmicrobesandenvironmentalpollutants
actinomycetesandfungi(Grinhutetal.,2007)playanimportantrolein arestronglyaffectedbyenvironmentalconditionsincludingpH,tem-
manyprocessesoccurringinsoilandcanevenmineralizeHS.HSdegra- perature,ionstrengthandredoxstate(VanTrumpetal.,2006).Climate
dationinsoilisdependentonenvironmentalconditions,includingtem- inducedchangesinthestructureofHS,resultingfromtheirmicrobial
perature,soilmoisture,pH,O2,presenceofnutrients,redoxpotential, transformationsarealsolikelytoalterthecharacterofbindingbetween
sorptioncapacityetc.(Castroetal.,2010;Kunc,1988;Steinberg,2003). HSandpollutants,whatmayleadtodesorptionandre-mobilizationof
IncreaseinsoiltemperaturecouldenhanceHSdegradation(Christ metalsandorganic pollutants.Stormevents,thedischargedrunoff
andDavid,1996;Parketal.,2015;Reyetal.,2005)andincreasethe andfloodingmightcontributetotheproblemandincreasetheconcen-
amountofsubstancesavailableformicrobialrespiration(Balseretal., trationoftoxicsubstancesinaquaticsystems.
2010;Dorrepaaletal.,2009;Zoggetal.,1997).Non-labilepartofSOM
ismoresensitivetotemperaturethanlabileSOM,andsomoreDOM 4.EffectofCConthequalityofsurfacefreshwater
willbeformedasaresultofglobalwarming(Coleetal.,2007;Kalbitz
etal.,2000;Knorretal.,2005;Ritsonetal.,2014a,2017). 4.1.GlobalconsequencesofCC
Ingeneral,ariseintemperaturecorrespondstoariseinmicrobial
activity(Balseretal.,2010;MandalandNeenu,2012;Whitakeretal., ConsequencesofCCarenumerousanddifficulttobepredictedpre-
2014).However,microbesliveincomplexcommunitiescomposedof cisely. They include rising sea levels, increased emission, extreme
verydifferentorganisms,whichareexpectedtorespondtoCCinadif- weatherevents,andchangesinbioavailabilityandenvironmentstabil-
ferentway.CCmaythereforealterspeciesdistributionsandinteractions ity(IPCC,1996;NASA,2018).ItisexpectedthatCCwillseriouslyaggra-
amongorganisms(Classenetal.,2015;Rivkinetal.,1996;Whitaker vate already existing freshwater problems. Freshwater, which is
etal.,2014;Zoggetal.,1997).Inadditiontotemperature,thesoilmois- necessaryforlife,constitutesonlyabout2.5%ofthewateronEarth.
tureandthefrequencyofwet/dryandfreeze/thawcycles,aswellas Most of it is locked up in permafrost (ca 69%) and in the ground
changesinprecipitation,canmodifythesoilaggregation.Theymay (30%).Surfacewater,inlakesandrivers,makesupabout1.2%ofall
havepotentialimportantimpactsontheavailabilityofHSand,asacon- freshwater(Shiklomanov,1993).ItispredictedthatCCwillintensify
sequence,onthemicrobialstructureandactivity(Castroetal.,2010; thewatercycle.Warmingisexpectedtobringanoverallincreasein
MandalandNeenu,2012). rainfallandinextremeprecipitation,includingflashflooding.However,
theanticipatedrainfallsoverdryareaswillnotnecessarilymakemore
3.2.InteractionsbetweenHSandsoilcontaminants wateravailablebecauseevaporationwillincrease(Donatetal.,2016).
Whilesomeplacesmayexperiencestormsurgesandlongerdroughts,
Soilsarereceivinglargequantitiesoftracemetalsfromawidevari- otherplacesmayenjoymilderweather(Bond-Lambertyetal.,2016).
etyofindustrialwastes(Nriagu,1996;NriaguandPacyna,1988).When Despitethepredictedglobalincreasesinrainfall,CCisalsoexpectedto
introducedintotheenvironment,heavymetalstendtoaccumulatein reducerainfallinmanyalreadydryregions.Accordingtotheestimate
soilsandsedimentsbecauseoftheiraffinityforsorptionprocesses(Su oftheIPCC,CCmightleadtothesituation,inwhichaboutonebillion
etal.,2014).Biogeochemicalprocesses(sorption/desorption,complex- peopleindryregionswouldsufferfromtheshortageofwater(Bates
ation,dissolution/precipitation,anduptake/releasebybiota)control etal.,2008).
themobilityofheavymetalsandthustheresidencetimeinsoilsand CCisexpectedtochangetheamountofHSinsurfacewatersandto
water(Reederetal.,2006).Althoughmanyofthemosttoxicsubstances altertheirstructureaswellaschangebioticandabioticinteractions
introducedintotheenvironmentbyhumanactivityhavebeenbanned withwatercontaminants.TheimpactofCConHSandthesurfacefresh-
orrestrictedinuse,manystillpersist,especiallyinsoilsandsediments. waterqualityissummarizedinFig.3anddescribedinSections4.2–4.5
Sorptiondirectlyorindirectlycontrolsallbioticandabioticprocessesin below.
soil,whichaffectmetalsandalsoorganicpollutants(Barthetal.,2009;
Bloomfieldetal.,2006;Elzwayieetal.,2017;Maetal.,2016;Smithetal., 4.2.InteractionsbetweenHSandmicrobesinfreshwater
2009;Sunetal.,2016;Wangetal.,2015;Wangetal.,2016;Whitehead
etal.,2009).TheinteractionsofHSwithpollutants,especiallysorptive Dissolved HS play an important role in freshwater ecosystems
processes,havebeenthesubjectofintensestudiesforseveraldecades (Steinbergetal.,2003,2008).Itcandecreasepollutantstoxicitythrough
andaredescribedinmanyoriginalandreviewpapersincludingPan formationofvariouschemicalcomplexeswithxenobioticcompounds
et al. (2008), Piccolo et al. (1992), Senesi and Miano (1995) and andmetals.DissolvedHSaretakenupandinduceavarietyofresponse
Werneretal.(2013). reactionsinorganisms(Steinbergetal.,2006,2009);theyserveasacar-
Generally,sorptioncoefficientsdecreasewithincreasingtempera- bon and energy source for microorganisms in water and soil
ture.Thiseffectisinverselyrelatedtowatersolubilitywhich,onthe (Lipczynska-Kochany,2018andrefs).DOMinteractswithfreshwater
contrary, increases with temperature for most organic compounds organismsinavarietyofwaysanditcontrolstheirgrowth(Steinberg
(DelleSite,2001;Jiaetal.,2010;Tremblayetal.,2005;Wangetal., etal.2009).ManyauthorsreportedHSroleinsupportingbacterialpro-
2010).ThroughcomplexationandbindingHScanenhancewatersolu- ductioninlakes,riversandblackwatermarsh(MoranandHodson,
bilityandmobilityofmetalsandotherpollutants(SpositoandWeber, 1990; Moran et al., 2000; Steinberg and Bach, 1996; Tranvik and
1986;VanTrumpetal.,2006).ManystudiesdemonstratedthatpH, Höfle,1987;Tranvik,1988;TranvikandSieburth,1989;Tranvik,1990,
temperatureandionicstrengthhaveanimportantinfluenceonthespe- 1992;Visser,1985a,1985b).Forinstance,TranvikandHöfle(1987)re-
ciation of metal and binding with HS and other soil constituents portedthatheterotrophicbacterialbiomassproducedonwaterfrom
(Benedettietal.,1995;Ghabbouretal.,2001;GüngörandBekbölet, humiclakewasdoubleascomparedtothatonclearwater.
2010;Havelcovaetal.,2009;Kjølleretal.,2004;PehlivanandArslan, LargeriversfrequentlyreceiveinputsofDOMfromsoilandwet-
2006;Reederetal.,2006;Sauveetal.,2000;Whiteheadetal.,2009; lands.CCisexpectedtoalterconditionsacrosstheEarthandtoinflu-
Wijngaardetal.,2017).HShavefoundanapplicationinremediation ence the DOM export. CC induced variations in runoff and
andbioremediationofsoilcontaminatedwithorganicpollutantsand temperaturewilllikelyresultinchangesintheDOMstructureandits
E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565 1553
Fig.3.ImpactofCConHSandsurfacefreshwater.
concentrationsinfreshwater(e.g.Benoyetal.,2007;ChristandDavid (Bloomfieldetal.,2006;Sjerpsetal.,2017;Whiteheadetal.,2009,
1996; Duan et al., 2017; Eimers et al., 2008; Porcal et al., 2009; Section3.1herein).CCisalsoexpectedtoinfluencetransportandredis-
Mortsch and Quinn, 1996; Porcal et al., 2015). During the last tributionpathwaysofpollutants,becauseadsorptionprocessesaretem-
30years,anincreaseinDOMconcentrationsinlakesandrivershas peraturedependentandsodirectlyaffectedbyCC(Kallenbornetal.,
beenalreadyobservedinEuropeandNorthAmerica(Hongveetal., 2012;Ripszametal.,2015).Moreintenseextremeeventslikestorms
2004;Evansetal.,2005;Freemanetal.,2001b, 2004;Porcaletal., andrainfallaswellasfloodingmayreleasepollutantsadsorbedtosed-
2009;Schindleretal.,1997;Vuorenmaaetal.,2006;WorrallandBurt imentsandsoil,andtransportthemtorivers,lakesandoceans.Melting
2004).ChangesinDOMstructureandconcentrationareexpectedto ofpolaricecapsandpermafrostmayremobilizepollutantsstoredin
varybecause,accordingtotheCCmodels,theCCeffectssuchasthefre- snowandiceand,asaresult,bringthembacktoaquaticecosystems
quencyofstorms,droughtandrunoffevents,willdependontheregion (Spezzano,2012).DOMbindsnutrients(N,P,Fe),metalsandotherpol-
(CoxandWhitehead, 2009;Eimerset al.,2008;Evanset al.,2006; lutants, affecting their toxicity and bioaccumulation (Section 2.1).
TranvikandJansson,2001).TerrestriallyderivedDOMisdecomposed Underalteredenvironmentalconditions,theDOMstructureanditsin-
bymarineaswellasestuarinebacterialcommunities(Eshametal., teractionswithcontaminantsmaychangeleadingtothereleaseof
2000;Rockeretal.,2012).Temperatureisconsideredtobeanimportant bound nutrients and pollutants, including toxic free metal cations
factoraffectingmicrobialproductionandspecificgrowthrateinestua- (BertilssonandTranvik,2000;Keltonetal.,2007;Shilleretal.,2006;
rine,costalandfreshwaterecosystems(Goldmanetal.,2013;Shiah StummandMorgan1995;Vähätaloetal.,2003).
and Ducklow, 1994). It is thereforelikely that CC will increase the
amountofDOMinsurfacewaters,enhancingtheobservedactivity.As 4.4.EffectofsunlightontheHS-microbialinteractionsinfreshwater
aresultofCC(higherwatertemperature,changesinrainfallandin-
creasednutrientinputs)harmfulalgalbloomsinfreshwaterandinma- Innaturalwaters,HSrepresentthemainfractionofDOMthatab-
rineenvironmentsareexpectedtoincrease(Paul,2008;Chapraetal., sorbssolarradiation(Pauletal.,2004,2006a).SunlightaffectstheHS
2017).Ontheotherhand,micro-algalgrowmayhaveabeneficialeffect –microbialinteractioninanumberofwaysandboth,benefitsandad-
becausemicro-algaecanbeconvertedtobiodieselfuel,allowingreduc- verseeffectsonaquaticorganismshavebeenreported(Amadoretal.,
ingtheuseofcarbon-basedfossilfuelssuchaspetroleum(Chisti,2008; 1989;BertilssonandTranvik,2000;Granélietal.,1996;Osburnetal.,
PienkosandDarzins,2009;Lardonetal.,2009;Mataetal.,2010;Sayre, 2001;Pauletal.,2004;Porcaletal.,2015;Scullyetal.,2003a,2003b;
2010). Steinberg,2014).
IncreaseoftemperatureandanenhancedbiodegradationofSOM
4.3.HSandpollutantsinsurfacewaters leadtoanincreaseintheproductionofDOM,whilethefloodingand
runoffexportDOMfromsoiltoriversandlakes.AnychangeinDOCcon-
EffectsofHSonbiodegradationinsoilhavebeenextensivelyinves- centrationsandpropertiesmayaffectbiological,chemicalandphoto-
tigated.However,muchlessattentionhasbeensofarpaidtoeffectsof chemicalprocessestakingplacethere.ThebrownDOMinlakeand
HSandCConthetoxicityandbiodegradationoforganicpollutantsin rivers absorbs solar light and undergoes photochemical reactions
freshwaterecosystemandinsediments(Delplaetal.,2009;Noyes whichmodifyitschemicalproperties.
etal.,2009).ResultsoffewstudiesconfirmthatHS-pollutantsinterac- PhotolysisofDOMproducesbioavailablelowmolecularorganic
tions can alter contaminants toxicity and their biodegradation compounds,whichserveasorganicnutrientsforheterotrophicbacteria
(TranvikandHöfle,1987). anditcanreleasetheDOM-boundinorganicnutrients,stimulatingthe
Climatewarmingandchangingrainfallpatternsareexpectedtoaf- microbialgrow(BertilssonandTranvik,1998,2000;Pauletal.,2004;
fectfateandbehavioroforganicpollutantsinsurfacewater.Mostof Tranviketal.,2009).Therefore,theincreasedconcentrationofDOMin
chemicalreactionsandmicrobialprocesses,includingDOMdegradation watermayhaveabeneficialeffectbecauseDOMstimulatesactivityof
anditsinteractionswithcontaminants,arefasterathighertemperature bacteriadegradingorganicpollutants.Ontheotherhand,sunlightcan
1554 E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565
damagemicroorganisms(Scullyetal.,2003a,b).Inadditiontodirect beappliedinacombinationofphysical,chemicalandbiologicalpro-
photolysis,microbescanbedestroyedbyfreeradicalsreleasedduring cesses(Kimetal.,2015;Liuetal.,2015;USEPA,1996;Vymazal,2013,
thephoto-irradiationofDOM(Steinberg,2014). 2014;Wuetal.,2015b),includingacombinationofbiologicallagooning
Anincreaseinbrowningofthesurfacewaters,causedbytheHS withasolardrivenphoto-Fentonreaction(Silvaetal.,2015)aswellas
washedfromthesurroundinglandmayhaveanadverseeffectonthe CWswithmicrobialfuelcells(MFCs(Dohertyetal.,2015).Another
waterquality.Ithasbeenrecentlyobservedthatanincreaseofthe novel systemhasbeen proposedbyJasper andSedlak(2013)who
amountofDOMresultedinincreasedabsorptionofsolarultraviolet havedemonstratedthatopen-watercellsinunitprocesstreatment
rays,preventedlightfrompenetratingwaterandkillingpathogens.In wetlandscanusesunlighttoremovetraceorganiccontaminantsfrom
somecases,browning decreasedtheability of sunlightto disinfect municipalwastewater.
waterbyafactorof10.Thus,anincreaseinbrowningofthesurfacewa- Constructionandapplicationsofwetlandstosurfacewatertreat-
ters,causedbyDOMwashedintothelakefromthesurroundingland menthavebeenextensivelystudiedanddescribedinnumerousother
may have an undesirable effect for drinking water supplies originalandreviewarticles(e.g.Caoetal.,2016;Chenetal.,2016;
(Williamsonetal.,2017). Chyanetal.,2016;CorbellaandPuigagut,2018;Hernández-Crespo
etal.,2017;Hijosa-Valseroetal.,2016;Jácomeetal.,2016;KKivaisi,
4.5.Surfacewaterremediationandproductionofdrinkingwater 2001; Li et al., 2014; Lin et al., 2015; Lizama et al., 2011; Martín-
Monerrisetal.,2013;Odingaetal.,2013;Papaevangelouetal.,2016;
4.5.1.Surfacewaterpollution Ruanetal.,2006;SundaravadivelandVigneswaran,2010;Tuetal.,
ItisexpectedthatchangesoccurringasaresultofCCwillhaveasig- 2014; Uggettia et al., 2016; Vymazal, 2010, 2014; Vymazal and
nificantinfluenceonthefreshwaterquality(Delplaetal.,2009).Surface Březinová,2015;Zhangetal.,2014,2015).
wateractsasareceptorofpollutants,whicharewashedoutandcarried Both,naturalandconstructedwetlandsareshallowwaterbodies,
bythesurfacerunoff.Theymayincludefuelandoil,detergentsandfer- vulnerabletoclimatechange.Theyaresensitivetochangesintheir
tilizersandvariouskindsoflitter.Riseoftemperaturewillenhancesoil watersupply(IPCC,1996)andsotheymaybestronglyaffectedbyalter-
microbial activity and production of DOM (Kalbitz et al., 2000; ationsinthehydrologicalregimesandprecipitation.OtherCCrelated
Section3.1),whichwillbewashedoutfromsoilandwetlandstofresh- factorsmayalsoplayanimportantrole.Theyincludeanincreasedtem-
water(Evansetal.,2005;Freemanetal.,2001a;Moetal.,2016;Ritson perature(KadlecandReddy,2001),changedevapotranspiration,bio-
etal.,2014b;Ritsonetal.,2017;Worralletal.,2003).Intensedown- geochemistry,amountsofsuspendedsedimentloadings(Burkettand
pourscanwashsoilHS(Shangetal.,2018)anddesorbedpollutants Kusler2000)andincreasesinthefrequencyofextremeclimateevents.
(Section3.2herein,Chouetal.,2018)intowatersourcesanditmay CCinducedenvironmentalchangesarelikelytoaffectCWsbioremedia-
complicatewatertreatmentprocesses.Ontheotherhand,droughtcon- tion by affecting aquatic organisms (Steinberg 2003a; Lipczynska-
ditionsandlowerstreamflowcanaggravatetheseproblemsbyconcen- Kochany,2018andrefs;Section3.1herein),aswellastheirinteractions
tratingpollutantsandlimitingdilution. withHSandpollutants(Section3.2here).
Inmanyplaces,surfacewaterpollutionisaseriousproblemandvar- Manywetlandprocesses,includingmicrobiallymediatedHSdecom-
iousremediationtechniqueshavebeenapplied(e.g.LiandChu,2003; positionandnitrogencyclingreactions(mineralization,nitrification,
Borin and Tocchetto, 2007; Cao et al., 2012; Centi and Perathoner, and denitrification), are affected by temperature (Hu et al., 2010;
2003).Watertreatmentmaybeconductedusingphysical,chemical, KadlecandReddy,2001;Liu2013).Thecoastalwetlands,suchasman-
and biological treatment technologies (Hamby, 1996; Wang et al., groves,mightbealsoinfluencedbytherisingofsealevels(Barrosaand
2012),usingex-situorin-situmethods.Intheex-situapproach,con- Albernaza,2014;ChristandDavid,1996;Duanetal.,2017;Eimersetal.,
taminatedwaterisremovedtobetreatedelsewhere,whilein-siture- 2008;IPCC,1996;Porcaletal.,2009;Reyetal.,2005).
mediation it is treated at the polluted site. Water remediation Variousprocesses,biological,chemicalorphysical,occurringinthe
processesaredesignedtomeetstandardsbasedonhistoricalclimate complexwetlandsystems,overlapandinteract.Theytakeplacewithin
conditions.UnderCCconditions,theexistingtechnologiesmayhave thevegetation,thewatercolumn,andinthesoilandinvolveplants,mi-
tobemodified(Pykeetal.,2011). croorganisms,soilmatrixandpollutantsinwastewater.Thesecomplex
processesarestillnotwellunderstood(Stottmeisteretal.,2003).How-
4.5.2.Naturalandconstructedwetlands(CWs) ever,itislikelythatCCinfluenceonvegetation,biologicalactivityand
Bioremediationtechnologies(i.e.remediationusingaquaticplants, waterchemistry(pH,alkalinity,temperatureanddissolvedoxygen)
aquaticanimalsandmicroorganisms,includingbacteriaandfungi) may have astrong effecton thewetlandperformance(e.g. Lizama
havebeenconsideredtobeparticularlyattractiveasin-situmethods etal.,2011;Paingetal.,2015;StefanakisandTsihrintzis,2012).Asare-
forthetreatmentofcontaminatedsurfacewater.Constructedwetlands sultofCC,adsorbedonsoilandsedimentsheavymetalsandothercon-
(CWs)arefullyhuman-madewetlandsforwastewatertreatment.They taminants,maybereleasedbacktowater.Stormeventsmayaffect
usenaturalwetlandprocesses,associatedwithwetlandhydrology, constructed (and natural) wetland discharges (Taylor et al., 1993,
soils,microbesandplants.Potentialofwetlandplantstotreatwastewa- 2013).Mostoftheprocessesoccurringinwetlandsareexpectedtobe
ters was recognized in Germany in the early 1950s (Seidel, 1955; affectedbyCC,buttheirresponsestoCCwilllikelyvary,dependingon
Vymazal,2011).Sincethelate1960s,whenthefirstfull-scalesystems theregion.TheeffectofCConwetlandsmaybecomplexanddifficult
werecreated,variousconstructedwetlands(CWs)andsemi-natural topredict(e.g.Champagne,2008;IPCC2001,2014;Erwin,2009;Junk
treatment wetlands (SNTWs) (Kadlec and Wallace, 2009; US EPA, etal.2013;KadlecandReddy2001;Pauletal.2006b).
2015;Vymazal,2011)havebeenusedtotreatwastewaterinmany
countries(e.g.Ateiaetal.,2016;Brix,1997;Chazarencetal.,2015;
Ghrabi et al., 2011; Mitsch and Gosselink, 2007; Wu et al., 2015a, 4.5.3.Productionofdrinkingwater
2015b;Tamiazzoetal.,2015).CWs,SNTWsaswellasartificialfloating HSstimulatemicrobialdegradationofpollutantsandtheyplaya
islands(AFs)canbeusedtotreatcollectedwastewaterfromvarious beneficialroleinremediationofsoil(Section3.2herein),wastewater
sources,includingmunicipalanddomesticwastewaters(Kimetal., and groundwater (e.g. Lipczynska-Kochany and Kochany, 2008a,
2016; Vymazal, 2011), industrial and agricultural wastewaters, 2008b,2009,2011;Section5.2herein).ApplicationofHSinnaturalre-
stormwater runoff and landfill leachate (e.g. Kadlec and Wallace, mediationofsurfacewater,highlycontaminatedwithnuclearwastehas
2009;Changetal.,2017;DengandNi,2013;Moratóetal.,2014;Sun beenalsoreported(Aleksandrovaetal.2010).However,HSpresencein
etal.,2017;USEPA,1996;Vymazal,2013,2014;Zhaoetal.,2012). drinkingwaterisunwanted.Theycontributetoodor,color,tasteaswell
Thesemethodscanbeusedastheonlytreatmentsbuttheymayalso astoacidityproblemsinwatersupplies.Theyareprecursorsofharmful
E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565 1555
(Singer,1999)disinfectionby-products(DBPs)(Bondetal.,2011,2012; forgroundwatersupplyishigh,whileinareaswherepermafrostorgla-
ChenandWesterhoff,2010;KimandYu,2007;Uyaketal.,2008). ciers melt, the groundwater recharge will increase (Dragoni and
Duringthepast20years,topicsrelatedtothepresenceofHSin Sukhija,2008;Pitz,2016).ResultsofstudiesonthepotentialCCeffect
drinkingwaterhavebeenstudiedbymanyresearchers(e.g.Hongve onthegroundwaterrechargehavebeendescribedinanumberoforig-
etal.,2004).ExtensiveresearchontheHSremovalfromwaterhas inalandreviewarticles(e.g.EarmanandDettinger,2011;Holman,
beenconductedusingvarioustreatmentmethods,includingcoagula- 2006;JyrkamaandSykes,2007;Milehametal.,2009;Meixneretal.,
tion,filtrationandadvancedoxidationprocesses.Resultshavebeende- 2016;Smerdon,2017).
scribedinnumerousoriginalandreviewpapers(e.g.Domanyetal. CCisexpectednotonlyaffectrechargeand(discharge),butalsoto
2002; Lamsal et al., 2011; Levchuket al.,2018;Loweand Hossain, influence the quality of groundwater (Dragoni and Sukhija, 2008,
2008;MatilainenandSillanpää,2010;Matilainenetal.,2010;Murray Greenetal.,2011;Tayloretal.,1993,2013;Taylor,2014).Therelation
and Parsons, 2004; Philippe et al., 2010; Stanford and Majeda betweenCCandgroundwaterisconsideredmorecomplicatedthan
Khraisheh,2009). thatwithsurfacewater.Groundwateraquifershaveahighstorageca-
AsaresultofCC,thequalityofthesourcefreshwaterisexpectedto pacityandarebelievedtobelesssensitivetoCCthansurfacewaters.
deteriorate.Drinkingwaterproductionfacilitiesarenotalwaysde- However,groundwatertemperaturemaybemoresensitivetoclimate
signedandequippedtohandletheincreasedconcentrationsofDOM warmingthanpreviouslybelieved.Recentreportsindicatethatincreas-
andothercontaminants.Theymayneedtoadapttheirprocessesto ing groundwater temperature may have a significant influence on
dealwithconsequencesoffrequentoccurrencesofextremeweather groundwaterandriverecology(Greenetal.,2011;Menbergetal.,
andwithvariableDOMconcentrations.Thus,modificationsoftheinfra- 2014;Pitz,2016).RelativelyfewstudiesonCCanditsinfluenceon
structuremightberequiredandhighercostofdrinkingwaterproduc- groundwaterhavefocusedonprocesses,whichmayaffectgroundwater
tioncanbeexpected(Delplaetal.,2009;Raekeetal.,2017;Ritson quality.TheyincludeinvestigationsofCCeffectsonpesticidefateand
etal.,2014a,2014b;Ritsonetal.,2016). transportinthesubsurface(Bloomfieldetal.,2006).
HSingroundwateroriginatefromrechargeorin-situgenerationby
5.EffectofCConthequalityofgroundwateranditsremediationin- partialdegradationofsedimentaryorganicmatter,includinglignite.HS
situ concentrationandcompositiondependsontherechargeconditions,af-
fectedbyCC(Artingeretal.,2000;Buckau,2005).ResultingfromCC,ex-
5.1.EffectofCCongroundwaterrechargeandquality pected intense downpours can wash out soil HS and desorbed
pollutantsnotonlyintosurfacewaterbutalsotogroundwater.Ex-
Globally,groundwateristhesourceofonethirdofallfreshwater pectedCCimpactsonthegroundwaterqualityhavebeensummarized
withdrawals,supplyinganestimated36%,42%,and27%ofwaterused inFig.4.
for domestic, agricultural, and industrial purposes, respectively HSplayakeyroleinthetransportofpollutants,includingheavy
(ShresthaandPandey,2016).Itistheworld'slargestreservoiroffresh- metalsandradionuclides.TheCCinducedchangesin thestructure
wateranditplaysanimportantroleinsustainingecosystemsanden- andquantityofHSingroundwatermayalterinteractionsbetween
abling human adaptation to climate variability and change. CC is metals,HS,soilsandsediments(Kjølleretal.,2004).Thesorptionof
expectedtohaveasignificantinfluenceonsoilwaterandtemperature, HSonoxidesandclaymineralsisknowntochangethephysicochemical
aswellasonsubsurfacehydrologicalandthermalprocesses(Green propertiesofrelevantinterfaces(Guetal.,1995,1996)anditisaffected
etal.,2011;Menbergetal.,2014).However,researchontheCCimpact bypHchangesJiangetal.,2014).HSformcomplexeswithironoxides
onwatersystemshasbeenfocusedmainlyonthesurfacewater,while throughvarioustypesoffunctionalgroupsandtheycansorbtomineral
potentialeffectsongroundwaterhavereceivedmuchlessattention surfaces(e.g.Tipping,1981;Liuetal.2008).HScandonateelectronstoa
(Aslametal.,2018). numberofdissolvedandsolidFe(III)compounds(BauerandKappler,
TheCChasapotentialtoaffectboththequalityandquantityof 2009)andmagnetite(Sundmanetal.,2017),resultinginthereduction
groundwater,predominantlythroughimpactsonrechargeandevapo- andsubsequentdissolutionofminerals.HS-induceddissolutionofmin-
transpiration.Groundwaterisrechargednaturallybyrainandsnow eralsmayresultinremobilizationofcontaminantspreviouslyadsorbed
meltandbyinteractionswithsurfacewater(rivers,lakesandwet- onitssurface.CCmayhaveasignificantimpactonthesecomplexenvi-
lands).Soilmoistureisalsoanimportantfactorinthegroundwaterre- ronmentalequilibria.PollutantscanbealsoadsorbedonHSandform
chargeprocess(Balek,1988;Sophocleous,2004).Groundwaterand stableaqueouscomplexes,whatmayimpacttheirremoval(Klausen
surfacewaterusedtobeconsideredseparateentities,andinvestigated etal.,2003;Liuetal.,2008;O'Loughlinetal.,1999;Sunetal.,2016).
individually.However,processesoccurringinthetransitionzonesmay
affect transport, degradation, transformation, precipitation, and/or
sorptionofcontaminants.Resultsofstudiesonexchangeprocessesbe-
tweengroundwaterandsurfacewaterhaveshownthatsuchinterac-
tionsmayhaveasignificantimpactonthewaterqualityofeitherof
these hydrological zones (Kalbus et al., 2006; Keery et al., 2007;
Sophocleous,2002;Stegenetal.,2016).
Anychangesintheregimeandquantityofprecipitation,together
withchangesintemperatureandevapotranspiration,haveasignificant
influenceonthegroundwaterrecharge.MoststudiesontheCCeffects
ongroundwaterhavefocusedonprocessesthataffectinput(recharge),
output(discharge),changesinstorage,aswellastheassociatedphysi-
calprocesseswhichcontrolsubsurface-waterflow.Itispredictedthat,
asaresultofCC,theoverallrateofgroundwaterrechargemayincrease.
Thehigherintensityandfrequencyofprecipitationispredictedtocon-
tributesignificantlytothesurfacerunoff,whileevapotranspirationrate
mayincreaseasaresultofglobalwarming.However,itisalsoexpected
thatclimate-relatedchangestothegroundwaterrecharge,storage,and
baseflowdischarge,willdependonlocalconditions.Theremaybedry
andsemi-dryareaswhereaquiferrechargeratesarelowanddemand Fig.4.ImpactofCCongroundwater.
1556 E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565
ItisexpectedthatchangesinDOMcompositionmayhaveaninflu- surfactantsallowingfordesorptionoftheorganiccompoundsfrom
enceonthefateoforganicpollutants,includingpolycyclicaromatichy- thesoilandsediments,andmakethemmoreavailableforbiodegrada-
drocarbons(PAHs)(Chenetal.,2017;Haftkaetal.,2010;Huretal., tion.However,underchangedconditions,dissolvedHScanadsorbto
2014).Metals,andotherpollutants,adsorbedonironmineralscanbe soilsandaquifermaterials,resultinginre-immobilizationofpollutants.
re-mobilizedandreleasedtogroundwater.Itmaybethereforeexpected HSarealsoknowntobindtomineralsurfacesandtometals(e.g.
thatanychangesinDOMconcentrationingroundwatersystemswill Davis, 1982, 1984; Davis and Leckie, 1978; Ho and Miller, 1985;
havealargeeffectonthegroundwaterpollution(Wengetal.,2009). KerndorffandSchnitzer,1980;Tipping,1981).Theinteractionsbe-
tweenHS,metalsandmineralsarestronglydependentonanumber
5.2.Groundwaterremediationin-situ of factors, including pH (e.g. Ho and Miller, 1985; Kerndorff and
Schnitzer,1980).ThemobilityofametalwithaffinityforHSisdeter-
Itisverylikelythatextremeweatherevents,causedbyCC,willlead minedbythemobilityofHS.Ingroundwater,HScandecreasemobility
toreductionofsurfacefreshwater.Inthissituation,groundwaterwillbe ofHS-bondedmetals,ifconditionsfavorsorptionofHStomineralsur-
criticaltorelievetheseriousfreshwaterproblems.Peopleinwater- faces.However,whenconditionsfavormobilityofHS,mobilitythe
scarce areas will become increasingly depended on groundwater. HS-complexedmetalmaybeenhanced.Dependingongeologicalcondi-
Therefore,theavailabilityandqualityofgroundwaterareofagreat tions,HScouldbeusedtomobilizesomemetalsoritcouldbeusedto
importance. enhancethesorptionofothermetals(Petrovićetal.1999).
Manygroundwatersitesarecontaminatedwithcomplexmixtures Ithasbeenconcludedthatanin-situapproachforremediationof
ofvariouspollutants,includingchlorinatedsolvents,fuels,metalsand/ groundwaterplumescouldbebasedontheinjectionofHSintothe
orradioactivematerials.Since1970s,pollutedsiteshavebeentreated aquifer, enhancing attenuation of some metals in the subsurface
usingthepump-and-treatsystems,i.e.bypumping-outgroundwater (Petrovićetal.,1999;WangandMulligan,2006;Denhametal.,2014,
fromthesubsurface,followedbyanabovegroundtreatmentandadis- 2015).Underthegroundwaterconditionstypicalofmanymetalandra-
chargebackintotheground.Asaresultofpumping,thegroundwater dionuclidecontaminantplumes,HSsorbwelltomineralsurfaces.Wan
levelislowered,leavingremainingpollutantsadsorbedtothesoil. etal.(2011)havedemonstratedthatpeatandsoilHS,whensorbedto
When,afterthetreatment,groundwaterreturnstoitspreviouslevel, SavannahRiverSitesoils,enhancedthesorptionofuraniumunder
adsorbedcontaminantsdissolve,whatiscalledthe“rebound”(Nyer, acidicconditions(pH=3.0to4.5).Denhametal.(2014,2015)have
2000a;USEPA,1996).Itispossiblethatmajorrainorfloodingevents, alsoconcludedthattheinjectedHSisapotentialattenuation-based
whichwilllikelybecomemorefrequentunderCC,mayaffectsuch methodforin-situremediationofacidicwasteplumescontainingura-
rebounds. nium,iodineI-129(butnotforstrontium,Sr-90). Oneshouldnote
Morerecently,variousatthesite(in-situ)remediationtechnologies thoughthattheHSadsorptiontosedimentmineralsvarieswithpH.In-
havebeendeveloped.Suchmethodsdonotneedanyextractionofcon- teractionsbetweenmetalsandHSaredependentonanumberoffac-
taminatedgroundwateroutoftheground.Instead,theremediationis tors,includingpH.ItisthereforepossiblethatCCinducedchangesin
carried out directly atthecontaminatedplume (Naftz et al.,2002; the aquifer conditions, might lead to release of some HS and re-
Nyer,2000b).Asignificantinterestinnaturalattenuationofmetals mobilizebondedmetals.Carefulmonitoringwouldbethereforere-
and organic pollutants in soil and in aquifers has been observed quiredandsomecorrectionsofthetreatmentmaybeneeded.
(Bekins et al., 2001; Bourg et al., 1992; NRC, 2000; Wang and InjectionofdissolvedHS,followedbyasubsequentinjectionofacid,
Mulligan,2006;Wiedemeieretal.,1999).Naturalattenuationisdefined hasbeenproposedasamethodforcreatingapermeablereactivebar-
bytheUSEnvironmentalProtectionAgency(USEPA)as“avarietyof rier,PRB(OesteandKempfert,1996;Palmer,2000;Thiruvenkatachari
physical,chemical,orbiologicalprocessesthat,underfavorablecondi- etal.,2008).PRBsfilledwithHShavebeenalsoreportedbyBalcke
tions,actwithouthumaninterventiontoreducethemass,toxicity,mo- etal.(2005),Kopinkeetal.(2005),WangandWang(2011).Humus
bility,volume,orconcentrationofcontaminantsinsoilorgroundwater” degradationinsoilisdependentonenvironmentalconditionsincluding
(Rittmann,2004).Thenaturalattenuationprocessesareconductedin- temperature,soilmoisture,pH,O ,redoxpotential,sorptioncapacity,
2
situandtheyincludebiodegradation;sorptionandchemicalorbiologi- etc.(Schmidtetal.,2011,Section3.1herein).Thus,CCinducedchanges
calstabilization,transformation,ordestructionofpollutants.Thesepro- oftheseconditionsarelikelytoaffecttheperformanceofHSPRBs.
cessesareexpectedtobeinfluencedbyCC. CCmayalsoaffecttheperformanceofPRBsfilledwithothermate-
HSandHS-basedproductsholdagreatpromiseasreactiveagents rials,includingironoxidesandmetalliciron(Gheju,2017;Henderson
forin-situremediation.Theycanperformmultiplefunctionsinbiotic andDemond,2007;Obiri-Nyarkoetal.,2014;Schereretal.,2008).
(Lipczynska-Kochany,2018)andabioticprocesses.Theirinteractions Under environmental conditions, iron undergoes corrosion (Evans,
withpollutantsandlivingorganismscanbeusedinremediationof 1981;Lipczynska-Kochanyetal.,1994;Sato,1989).Atacidicandanoxic
soil andgroundwater. Anextensiveoverviewof HSpropertiesand sites,attenuationproceedsmainlythroughreductionandimmobiliza-
their potential applications have been given by Perminova and tion on the iron surface (Matheson and Tratnyek, 1994; Tratnyek
Hatfield(2005).PropertiesofnaturalHSdependontheiroriginandso etal.,2003).However,atneutralpH,corrosionproductsbecomeimpor-
the reactivity of HS from different sources may vary significantly tant.Presenceofironoxidesonthezerovalentiron(ZVI)PRBshasbeen
(Angstetal.,2018).Therefore,aconceptofachemicalmodificationto demonstratedinmanylabandfieldsexperiments(e.g.Farrelletal.
designtheHSmaterialsofadesiredremedialactivityhasbeenintro- 2001;Furukawaet al.,2002;Jiao,et al.,2009;Phillipset al.,2003;
duced.ManufacturedHS,withenhancedthenaturalHSproperties, Wilkinetal.,2005;Su,2007).Pollutantsareremovedfromgroundwater
havebeendescribedbyPerminovaetal.(2004,2011,2012,2014)and by adsorption/co-precipitation on the corroding iron surface
Volikovetal.(2016a,b). (Noubactep, 2010), along with redox transformations mediated by
Permeablereactivebarriers(PRBs)andin-situflushingareconsid- iron(hydr)oxidescoatingonthesurfaceofiron(Johnsonetal.,1998;
eredtobethemostpromisingtechnologiesapplyingHS(Perminova Schereretal.,1998;Ritteretal.,2002).TheZVIPRBtechnologyhas
andHatfield,2005).In-situflushinginvolvestheinjectionorinfiltration been described in many original and review articles (e.g. Ghauch,
ofanaqueoussolutionintoazoneofcontaminatedsoiloraquifertoat- 2015;Gheju,2017;Guanetal.,2015;HendersonandDemond,2007;
tenuate metals and organic pollutants in soils and aquifers (Nyer, ITRC,2011,Noubactep,2015;Sunetal.,2016).However,therehas
2000b). HS are used as flushing agents to treatsites contaminated beenlittleinterestsofarinthepotentialeffectofCContheperformance
withdieselfuel,PAHsandotherorganiccontaminants(Conteetal., ofPRBs.
2005; Georgi et al., 2007; Lesage et al., 2001; Van Stempvoort and Warner(2007)notedthattheclimate-inducedshiftsinhydraulic
Lesage2002;VanStempvoortetal.,2002a,b,2005).HSactasnatural gradients(resultingfromshiftingrainfallpatterns,risingsealevels,
E.Lipczynska-Kochany/ScienceoftheTotalEnvironment640–641(2018)1548–1565 1557
andfluctuatingriverlevels)maybeareasonforconcern.Hesuggested subsurfaceanditmayaffecttheperformanceofPRBs,whichareusually
thatsitedesignshouldtakeunderconsiderationpossibleshiftsinthe placedinthegroundfordecades.Itcanbeexpectedthat,asaresultof
hydraulicgradientcausedbyCC.Nevertheless,manyotherenviron- CC,thequalityofsourcefreshwaterwilldecline,whatwillaffectthe
mentalfactorsmayalsohaveaneffectonthePRBsperformance.They productionofdrinkingwateranditmayincreasethetreatmentcost.
includecharacteristicsoflocalconditione.g.temperature,pH,dissolved
oxygen,aswellaswaterchemistry(e.g.,anions,cations,HS)andpres-
7.Conclusions
enceofmicroorganisms.Theseinfluences,stillnotwellunderstood,
shouldnotbeconsideredindividuallyisolatedbecause,innaturalsys-
CCisexpectedtohaveasignificantimpactonHSandonthequality
tems,theyusuallyaffecteachanother(Sunetal.,2016).
offreshwater.AsaresultoftheCCinducedbiodegradationofSOM,and
Theironoxidewaterinterfaceisaverydynamicregioncharacter-
anenhancedconcentrationofdissolvedHSinfreshwater,microbial
ized by sorption, desorption, growth, and dissolution processes
growthmaybestimulatedandbiodegradationofpollutantsinwater
(Brownetal.,1999;CornellandSchwertmann,2003).Adsorptionof
canbeenhanced.Ontheotherhand,negativeeffectsmaybealsoex-
contaminantsonironhydroxides,andinteractionswithHS,depend
pected,includinganinhibitionofsolardisinfectioninbrownlakesas
stronglyonpHbecausethesurfacechemistryandthesurfacecharge
wellasanimpactonthetreatmentoffreshwaterin-situ.Complexand
oftheironhydroxidesoxidesvary.Removalofpollutantsadsorbedon
stillnotfullyunderstood,naturalattenuationprocessesmaybeaffected
oxidessurfaceisstronglyinfluencedbypHandtemperature.Changes
inawaydifficulttobepredicted.Itispossiblethat,dependingonthe
intheseconditionsmaybecriticalforthereleaseofmetals(Jiao,etal.,
localconditions,toxicpollutantsmaybere-mobilizedfromsediments
2009;Kumaretal.,2015)andotherpollutantsimmobilizedonthe
and/or from some PRBs surface, increasing contamination in the
PRBssurfaceorontheironmineralsingroundwatersediments.
groundwatersystems.ManyofthepossibleCCeffects,describedin
Transformationofpollutantsadsorbedonironoxidescanbeen-
thisarticle,haveyettobeexploredandunderstood.Hopefully,the
hancedbyironreducingmicrobes(VanNootenetal.,2008;Philipps
enormouspotentialforinteresting,multidisciplinaryresearchwillen-
etal.,2010),whosegrowthisdependentonpH,oxygenandtempera-
couragereadersofthisreviewtoconductstudiesinthisimportant
ture(ITRC,2011).Presenceofsulfate-reducingbacteriainoraround
andstilllargelyoverlookedresearcharea.
ironbarriersandthesubsequentformationofironsulfidescanalsoin-
crease transformation of contaminants (Lipczynska-Kochany et al.,
1994;Kumaretal.,2015;VanNootenetal.,2007).Insoilandsediments Acknowledgment
environments,metaloxidesandbacteriatendtobeassociatedwith
each another. Interactions between HS and bacteria (Lipczynska- AuthorisgratefultotheEditorandtotheanonymousRefereesfor
Kochany2018andrefs)aswellasprocessesoccurringonthePRBSsur- theirhelpfulcomments.
face,includingthesorptionofHSonironoxide-bacteriacomposite
(Jiang,etal.,2014),arestillnotwellunderstood.PotentialroleofCC References
changeoncomplicatedprocesses,relevantforthein-situremediation
Aeschbacher,M.,Brunner,S.H.,Schwarzenbach,R.P.,Sander,M.,2012.Assessingtheef-
ofgroundwater,areyettobeexplored.
fectofhumicacidredoxstateonorganicpollutantsorptionbycombinedelectro-
chemicalreductionandsorptionexperiments.Environ.Sci.Technol.46:3882–3890.
6.Summary https://doi.org/10.1021/es204496d.
Aiken,G.R.,Hsu-Kim,H.,Ryan,J.N.,2011.Influenceofdissolvedorganicmatterontheen-
vironmentalfateofmetals,nanoparticlesandcolloids.Environ.Sci.Technol.45:
Humicsubstances(HS)arethemajorcarbonpoolinthebiosphere 3196–3201.https://doi.org/10.1021/es103992s.
andtheirimportantroleintheglobalwarminghasbeenrecognized Aleksandrova,O.N.,Schulz,M.,Matthies,M.,2010.Naturalremediationofsurfacewater
systemscontaminatedwithnuclearwasteviahumicsubstancesinSouthUral.
andextensivelystudied.However,muchlessattentionhasbeenpaid
WaterAirSoilPollut.206:203–214.https://doi.org/10.1007/s11270-009-0096-7.
sofartoeffectsonthesurfacewaterandgroundwaterquality,which Alexandri,G.,Georgoulias,A.,Meleti,C.,Balis,D.,Kourtidis,K.A.,Sanchez-Lorenzo,A.,
mayresultfromtheclimateinducedimpactonHS.Increaseintemper- Trentmann,J.,Zanis,P.,2017.Ahighresolutionsatelliteviewofsurfacesolarradia-
atureandenhancedbiodegradationofSOMleadstoanincreaseinthe tionovertheclimaticallysensitiveregionofEasternMediterranean.Atmos.Res.
188:107–121.https://doi.org/10.1016/j.atmosres.2016.12.015.
productionofDOM,whilethefloodingandrunoffexportitfromsoil Amador,J.A.,Alexander,M.,Zika,R.G.,1989.Sequentialphotochemicalandmicrobialdeg-
torivers,lakesandgroundwater.IncreasedconcentrationofDOMin radationoforganicmoleculesboundtohumicacids.Appl.Environ.Microbiol.55,
waterwillstimulatemicrobialgrowthanditmayenhancebiodegrada- 2843–2849.
Angst,G.,Messinger,J.,MariaGreiner,M.,Häusler,W.,Hertel,D.,Kirfel,K.,Kögel-Knabner,
tionofpollutantsinwater.However,itmayhavealsonegativeeffects,
I.,Leuschner,C.,Rethemeyer,J.,Mueller,C.W.,2018.Soilorganiccarbonstocksintop-
includinganinhibitionofsolardisinfectioninsurfacewaters.Increase soilandsubsoilcontrolledbyparentmaterial,carboninputintherhizosphere,and
inDOMconcentrationsinthesourcefreshwatermaycreateproblems microbial-derived compounds. Soil Biol. Biochem. 122:19–30. https://doi.org/
10.1016/j.soilbio.2018.03.026.
fordrinkingwaterproductionfacilities.
Artinger,R.,Buckau,G.,Geyer,S.,Fritz,P.,Wolf,M.,Kim,J.I.,2000.Characterizationof
ClimateinducedchangesinthestructureofHS,resultingfromtheir groundwaterhumicsubstances:influenceofsedimentaryorganiccarbon.Appl.
microbialtransformations,aswellaschangesinacidityandotherenvi- Geochem.15:97–116.https://doi.org/10.1016/S0883-2927(99)00021-9.
Aslam,R.A.,Shrestha,S.,Pandey,V.P.,2018.Groundwatervulnerabilitytoclimatechange:
ronmentalfactorswillalterthecharacterofbindingbetweenHSand
Areviewoftheassessmentmethodology.Sci.TotalEnviron.5(612-853-875).
contaminants.Asaresult,re-mobilizationofmetalsandorganicpollut- https://doi.org/10.1016/j.scitotenv.2017.08.237.
ants,andtheirsubsequentwash-upfromthesoilandsedimentssur- Ateia,M.,Yoshimura,C.,Nasr,M.,2016.In-situbiologicalwatertreatmenttechnologies
forenvironmentalremediation:areview.J.Bioremed.Biodegr.7:348–353.https://
faces may beexpected.Thereis a concern that CCwill have broad
doi.org/10.4172/2155-6199.1000348.
negativeimpactsonthebehaviorandfateofmanyfreshwatercontam- Balcke,G.,Georgi,A.,Woszidlo,S.,Kopinke,F.D.,Poerschmann,J.,2005.Utilizationof
inants.Both,naturalandconstructivewetlandsareexpectedtobeinflu- immobilized humic organic matter for in-situ subsurface remediation. In:
encedandthein-situsurfacewatertreatment(CWs)maybeupset.Itis Perminova,I.V.,Hatfield,K.,Hertkorn,N.(Eds.),UseofHumicSubstancestoRemedi-
atePollutedEnvironments:FromTheorytoPractice.NATOScienceSeries(SeriesIV:
alsoanticipatedthat,asaresultofthesurfacewatershortage,demand Earth andEnvironmental Series)Vol.52. Springer, Dordrecht. https://doi.org/
forgroundwaterwillincrease.Groundwaterqualityanditseffectivere- 10.1007/1-4020-3252-8_10(PrintISBN978-1-4020-3250-9).
mediationarethereforeofagreatimportance.Processesrelevanttothe Balek,J.,1988.Groundwaterrechargeconcepts.In:Simmers,I.(Ed.),EstimationofNatu-
ralGroundwaterRecharge.NATOASISeries(SeriesC:MathematicalandPhysicalSci-
groundwatertreatmentconductedin-situarestronglydependenton
ences)Vol.222.Springer,Dordrecht DOI.https://doi.org/10.1007/978-94-015-7780-
theenvironmentalconditions.Changesinacidityandotherenviron- 9_1.
mentalfactorswillalterthecharacterofbindingbetweenHS,contami- Balser,T.C.,Gutknecht,J.L.M.,Liang,C.,2010.Howwillclimatechangeimpactsoilmicro-
bialcommunities?In:Dixon,G.R.,Tilston,E.L.(Eds.),SoilMicrobiologyandSustain-
nantsandminerals.Therefore,CC(andincreasedconcentrationsof able Crop Production. Springer Science + Business Media B.V. :pp. 373–397
DOM) may have a significant influence on processes occurring in Chapter10.https://doi.org/10.1007/978-90-481-9479-7_10