research article sulfur speciation in the surface...

Research ArticleSulfur Speciation in the Surface Sediments ofLakes from Different Regions China Characterization byS K-Edge XANES Spectroscopy

Wang Jingfu1 Chen Jingan1 Dai Zhihui2 Yang Haiquan1 and Ma Chenyan3

1State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550081 China2State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550081 China3Institute of High Energy Physics Chinese Academy of Science Beijing Synchrotron Radiation Facility Beijing 100049 China

Correspondence should be addressed to Chen Jingan chenjinganvipsklegcn

Received 9 March 2016 Accepted 28 April 2016

Academic Editor Stanislav Franciskovic-Bilinski

Copyright copy 2016 Wang Jingfu et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

X-ray absorption near edge structure (XANES) spectroscopy affords the opportunity to determine redox status for element S in theaquatic ecosystems However there have been relatively few studies of S XANES spectroscopy in the terrestrial aquatic ecosystemsIn this study XANES technology was used to examine changes in S speciation in the sediments collected from Taihu Lake QinghaiLake Dianchi Lake Caohai Lake and Hongfeng Lake located in distinct geological background areas of ChinaThe results showedthat sedimentary S in Qinghai Lake has a high proportion of sulfate averaged 889 due to physical weathering of watershed rockswhile deposited S in Taihu Lake has a high fraction of intermediate S (365) which may be the response of the agriculturalnonpoint source pollution in drainage basin The three lakes located in Southwest China have similar composition characteristicsof S species indicating similar S sources including chemical weathering of carbonate and atmospheric deposition 60ndash90 of Scompounds in the surface sediments were in the form of sulfate and FeS In deeper layers the ratio of FeS

2and the intermediate S

significantly increased suggesting rapid processes of sulfate reduction and sulfide reoxidation with the increasing depths

1 Introduction

Sediment is an important repository and sink for sulfur (S)[1] The biogeochemical cycles of S in sediments were highlycomplex because the aquatic ecosystems have anaerobiczones which strongly affect the chemical forms of S [2 3] Inthe previous studies thewet-chemical speciationmethodwasgenerally used to analyze the S speciation in sediments andreveal its geochemical processes in the aquatic ecosystems [4ndash9] In fact and often neglected S in natural samples existed ina large variety of organic and inorganic forms with differentelectronic oxidation states ranging from minus2 (inorganic sul-fide) to +6 (sulfate) [10] This made traditional wet-chemicalS speciation complicated [11] Therefore sensitive analyticalmethods are needed to analyze and monitor many functionsand transformations of S species in biochemical reactionsand in our environment [12] X-ray absorption near edgestructure (XANES) spectroscopy affords the opportunity to

determine redox status and coordination environment for awide variety of elements including sulfur carbon and nitro-gen within these sediments [13] The method has becomeespecially attractive for the speciation of S in sediments andother environmental samples most prominently at the S K-edge [10 12 14 15]

In previous investigations XANES spectroscopy has beenapplied to the analysis of the chemical form and oxidationstate of S in soil and marine sediments [10 12 16] providinginformation about the deposition and diagenesis of organicmatter and S mineralogy However there have been relativelyfew studies of S XANES spectroscopy in sediments of theterrestrial aquatic ecosystems [17] Particularly comparativestudies of the oxidation states of sedimentary S in differenttypes of lakes from distinct geological background areasare scarce In this study we used the K-edge XANES todetermine S speciation in the sediments collected fromTaihu Lake (Eastern China) Qinghai Lake (Western China)

Hindawi Publishing CorporationJournal of ChemistryVolume 2016 Article ID 3672348 9 pageshttpdxdoiorg10115520163672348

2 Journal of Chemistry

Beijing

Qinghai Lake

Taihu Lake

Dianchi Lake

Caohai LakeHongfeng Lake

N

QH

TH

HF

CH

DC

0 1000(km)

0 10(km)

0 5(km)

0 20(km)

0 30(km)

0 60(km)

20∘

30∘

40∘

90∘E 100

∘110

∘120

∘

Figure 1 Location of the studied lakes

Hongfeng Lake (Southwest China) Caohai Lake (SouthwestChina) and Dianchi Lake (Southwest China) The objectis to understand the S speciation and its transformation insediments of the terrestrial aquatic ecosystems

2 Materials and Methods

21 Area Description In this study five lakes were chosenbased on economic and geographic status in the YangtzeRiver region Southwest Plateau and Qinghai-Tibet PlateauChina (Figure 1) Geographic and limnological features forthe five selected lakes are shown in Table 1 [18 22] TaihuLake is the third largest freshwater lake in China locatedat the downstream of the Changjiang River More than 200brooks canals and rivers discharge industrial wastewatermostly from nearby cities into the lake Many effluents con-tain pesticides toxic chemicals or heavy metals SouthwestPlateau China is the largest karst area in China Accordingto previous lake chemistry surveys [23] one slightly pollutedlake (Caohai Lake) and two heavily polluted lakes (DianchiandHongfeng Lakes)were selected in this areaQinghai Lakea closed-basin lake is the largest inland saline lake in ChinaThe amount of evaporation (sim1400mmyear) is in excess ofthe mean annual precipitation (sim400mmyear) resulting inthe development of a saline lake

22 Sampling Procedures Sediment core samples wereobtained from the five lakes in September 2013 nearly inthe centre of the lakes A plastic static gravity corer with

30 cm length and 6 cm diameter Plexiglas cylinder tube wasemployed to obtain the sediment cores The core sampleswere sliced with intervals of 2 cm with the exception of thecore from Qinghai Lake sectioned at 1 cm intervals Sedi-ments were handled under protective nitrogen atmospheres(purity 999 Guiyang Shenjian Gas Co Ltd) All sampleswere put in sealed plastic bag and immediately transferredto laboratory in iceboxes (lt4∘C) and freeze-dried After thatthe samples were frozen with liquid nitrogen Before XANESanalysis dry samples were ground and sieved with a standard100-mesh sieve

23 Sulfur K-Edge XANES The sulfur K-edge XANES spec-tra were recorded at 4B7A beamline (medium X-ray beam-line 2100ndash6000 eV) using synchrotron radiation from BeijingSynchrotron Radiation Facility the Institute of High EnergyPhysics the Chinese Academy of Sciences The samples werepressed into thin films before analysis The storage ring wasoperated at the energy of 25 GeVwith Si (111) double crystalsSpectra were scanned at step widths of 03 eV in the regionbetween 2420 and 2520 eV with fluorescence mode usinga fluorescent ion chamber Si (Li) detector (PGT LS30135)Additional filters were placed between the sample and thedetector to reduce the fluorescence signal derived from Si inthe samples

Fe monosulfide (FeS) pyrite (FeS2) R-SH RSOR1015840

Na2SO3 NaRSO

3 and Na

2SO4were chosen as the standard

compounds Electronic oxidation states white-line energiesand intensities of reference S compounds were shown in

Journal of Chemistry 3

Table 1 Geographic and limnological features of the studied lakes [18ndash21]

Parameters Eastern China Southwestern China Western ChinaTaihu Lake Hongfeng Lake Dianchi Lake Caohai Lake Qinghai Lake

Positions 30∘051015840ndash32∘081015840N119∘081015840ndash121∘551015840E

26∘251015840ndash341015840N106∘201015840ndash281015840E

24∘401015840ndash25∘021015840N102∘361015840ndash∘471015840E

26∘491015840ndash531015840N104∘121015840ndash181015840E

36∘321015840ndash37∘151015840N99∘361015840ndash100∘471015840E

Surface area (km2) 2338 56 306 20 4583Elevation (m) 5 1235 1886 2171 3196Maximum depth (m) 26 450 80 25 328Water

pH 836 840 737 878 935DO (mgL) 101 88 89 94 NDSalinity (gL)

lt10 lt10 lt10 lt10 125Sulfate (mgL) 100 80 60 40 2500

SedimentOrganic matter () 65 54 65 ND 24TN () ND 031 033 138 050TP () 008 016 015 007 NDFe () 265 598 ND ND 250

Climate type Warm humid Warmsemihumid

Warmsemihumid

Warmsemihumid Cool semiarid

Deposition rate (cmyr) ND 016 020 025 010

Table 2 The X-ray energy was calibrated with referenceto the spectrum of the highest resonance energy peak ofNa2SO4at 24804 eV For all edge-normalized spectra the

contribution of different S species to total S was calculatedusing the software package ATHENA (Ravel and Newville2005) Linear combination fitting (LCF) was carried out inthe energy range 2466ndash2487 eV using the ATHENA [10]

24 Analysis of the Total Sulfur Total S contents weremeasured with an elemental analyzer (vario MACRO cubeElementar Germany) with an experimental error of 05Two certified reference materials (RTS-2 and KZK-1 StateKey Laboratory of Environmental Geochemistry Instituteof Geochemistry CAS) were used as calibration standardConcentrations of total S in sediments of the five studied lakeswere shown in Table 3

3 Results and Discussion

31 S Species in Lake Sediments Our sediment samples eachcontain both oxidized and reduced sulfur species as shownin Figure 2 Two major absorption bands were observed inthese K-edge XANE spectra one near 2472 eV region for thereduced S compounds (eg FeS and FeS

2) and another near

2483 eV region for oxidized S species (eg SO4

2minus) suggestingthat sulfate and FeS were the most important componentof elemental S in all lakes However in different lakes thecompositions of the oxidation state of S in sedimentswere stillvery different Figure 2 showed that the overall absorptionintensity of S was the lowest in the sediment of Taihu Lakeindicating the lowest concentration of S component in thesediments Further organic state S obviously occupied a

Table 2 Electronic oxidation states white-line energies and inten-sities of reference S compounds

Compound Electronicoxidation state

White-lineenergy (eV)

White-lineintensity

FeS minus2 24722 117FeS2

minus1 24728 133RSH +05 24734 158RSOR1015840 +2 24762 181Na2SO3

+368 24784 203NaRSO

3+5 24812 233

Na2SO4

+6 24826 254

relatively high proportion of in the oxidation state of S insediments of Taihu Lake compared with other lakes Inthe three lakes located in the Southwestern China that isDianchi Lake Caohai Lake and Hongfeng Lake the oxida-tion state of the sedimentary S presented similar compositioncharacteristicsThe concentrations of sulfate FeS and S

2O3

2minus

were high of the top three and the contents of other S formswere relatively low In the sediments of Qinghai Lake theoxidation states of S were mainly sulfate FeS and FeS

2and

almost no organic sulfur Moreover FeS2was found in the

surface sediments of Taihu Lake and Qinghai Lake and didnot exist in the surface sediments of the three lakes located inSouthwestern China

Figure 2 also demonstrated that the absorption intensityof S significantly reduced with the increasing depths in allsediment profiles revealing a reduction of the concentrationof S in deeper layers Figure 3 showed the vertical variation ofthe oxidation states of S in the sediment profiles suggesting


Table 3 Concentrations of total S in sediments of Taihu Lake Hongfeng Lake Dianchi Lake Caohai Lake and Qinghai Lake

Depth cm Taihu Lake Hongfeng Lake Dianchi Lake Caohai Lake Qinghai Lake0ndash2 0170 0695 0662 1227 03933-4 0066 0657 0509 1428 03755-6 ND 0795 0622 1659 03847-8 ND 0 810 0469 1495 05239-10 ND 1175 0911 1221 041711-12 ND 0926 0817 0850 ND13-14 ND 0618 0483 1168 ND15-16 ND ND 0527 0388 ND17-18 ND ND 0425 0559 ND19-20 ND ND 0326 0512 ND21-22 ND ND 0381 0346 ND23-24 ND ND 0136 0425 ND

that S in sediments changed from the oxidation state to thereduced state with the increasing depths Oxidation states ofS in Dianchi Lake showed that sulfate and FeS were majorforms in the top 10 cm sediment which were considered tobe the most stable in all oxidation states of S in sedimentsIn the deeper layers the ratio of FeS

2and organic S forms

in the total S was significantly increased suggesting thatsulfate was chemically or biologically reduced in the deeppart of the sediments S in sediments of Caohai andHongfengLake showed similar composition and change characteristicswith that in Dianchi Lake In Qinghai Lake the proportionof the FeS and FeS

2slightly increased in 0ndash6 cm sediment

layer then reduced in the depths of 6ndash10 cm Accordinglythe proportion of sulfate reduced first and then increasedsuggesting an occurrence of S reduction and reoxidationprocesses

In the large-scale the five lakes in this study were locatedin three different natural regions which have the varied cli-matic economic and geological features Qinghai Lake basinwas an arid climate area in the Northwestern China where itusually received low inputs of mean annual precipitation andhad high potential evapotranspiration [24] Acid depositionwas mainly formed from SO

2emitted to the atmosphere

largely because of fossil-fuel combustion [25] Qinghai Lakearea was essentially unaffected by acid deposition indicatingthat atmospheric S has a relatively low concentration [26]Thus S in sediments of this lake mainly derived from physicalweathering of watershed rocks Taihu Lake was located inthe economically developed eastern coastal areas of ChinaAs shown in Figure 3 largely organic S originated fromindustry and agriculture in the lake basin occupied a highproportion in total S in the sediments S in sediments ofTaihu Lake on the one hand reflected the composition ofthe soil S of the lake basin and on the other hand wasaffected by human activities such as industry agriculture andatmospheric deposition For the three lakes located in thelargest karst region in Southwestern China that is DianchiLake Caohai Lake and Hongfeng Lake chemical weatheringof carbonate was the most important source of S Theprevious studies demonstrated that considerable emissions ofS compoundsmainly occurred in southern and Southwestern

China due to subsequent consumption of coal and oil whichincreased rapidly since the 1970s [26] Dry andwet depositionof atmospheric S caused by the coal combustion may beanother important source for these three lakes

Furthermore the eutrophic status of lakes may impacton the S deposition in the lake environment In our studymost of the lakes have changed from oligotrophy to of meso-or eutrophic conditions during the past decades because ofnutrient loading from wastewater and fertilizers especiallyTaihu Lake and Dianchi Lake [19 20] Only Qinghai Lakewas still in the oligotrophy condition Holmer and Storkholm[27] indicated that deposition of S was generally higher ineutrophic than in oligotrophic lakes because of a numberof factors a higher rate of sulfate reduction enhancedsedimentation of organic S and less reoxidation as a resultof reduced penetration of oxygen into the sediments a lackof faunal activity and rooted macrophytes Our survey dataas shown in Figure 3 showed that the proportion of S2minusand S

2

2minus in the sedimentary S in the eutrophic lakes suchas Taihu Lake was indeed significantly higher than thatin Qinghai Lake which was consistent with the results ofprevious studies [27] Currently there is however still ageneral lack of understanding of the interactions between Scycling and eutrophication One example is the interactionbetween S cycling and benthic fauna and rootedmacrophytesas they may be significantly impacted by eutrophication [27]However we believed that the impacts of S bacteria weremore reasonable S reduced from varied oxidation statesinto sulfides through the complex biochemical processeswas generally assumed to be the dominant pathway for thepermanent removal of S in the sediment [5] Reduction of Sin sediments ismainly dominated by SRBwhile the eutrophiclakes generally have a high SRB in sediment layers thus theproportion of most reduced S (oxidation state lt 0) in thesediment of eutrophic lake is higher than in oligotrophiclakes In particular Hongfeng Lake was a seasonally stratifieddeep-water lake After destratification and during winterthe anoxic hypolimnion becomes mixed with overlying oxicwater which enhances oxygen penetration into the sedi-ments This leads to an increased oxidation of reduced Sfollowed by a higher sulfate concentration [28]


246 247 248 249 250245White-line energy (KeV)

0000

0002

0004

0006

0008

0010

0012

Inte

nsity

0ndash2 cm3-4 cm

(a) Taihu Lake

000

002

004

006

008

010

012

Inte

nsity


9-10 cm0-1 cm

(b) Qinghai Lake


000

002

004

006

008

010

012

Inte

nsity

0ndash2 cm

21-22 cm11-12 cm

(c) Dianchi Lake

000

002

004

006

008

010

012

Inte

nsity


0ndash2 cm9-10 cm21-22 cm

(d) Caohai Lake

000

002

004

006

008

010

012

Inte

nsity



(e) Hongfeng Lake

Figure 2 Vertical variations of oxidation states of different S compounds in sediment profiles of Taihu Lake Qinghai Lake Dianchi LakeCaohai Lake and Hongfeng Lake China


Taihu Lake

Caohai Lake

Hongfeng Lake

Qinghai Lake

Dianchi Lake

40 60 80 1000 20Mass percentages of S forms ()

22

18

14

10

6

2

Dep

th (c

m)

10

7

4

1

Dep

th (c

m)


2

Dep

th (c

m) 40 60 80 1000 20

Mass percentages of S forms ()

14

10

6

2

Dep

th (c

m)



22

18

14

10

6

2

Dep

th (c

m)

FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus

Figure 3 Mass percentages of sulfur in FeS FeS2 R-SH RSOR1015840 SO

3

2minus RSO3

minus and SO4

2minus as calculated by Linear Combination Fitting on SK-Edge XANES spectra

32 Composition Ratio of Different S Compounds in SedimentProfiles The composition ratios of different S species insediment cores were shown in Figure 3 XANES fittingprocedures revealed that 60ndash90 of the total S compoundsnear the surface (0ndash10 cmdepth) of the lake sediment sampleswere in the formof sulfate andFeS FeS

2and the S specieswith

intermediate oxidation states between 0 and +6 accounted fora high proportion of total S in the deeper layers

Figure 3 showed that there were wide variations in thefractions of the sedimentary S species in different lakes Inthe surface sediment of Taihu Lake sulfate FeS

2 and FeS

accounted for 389 126 and 110 of the total S while theS species with intermediate oxidation states between 0 and +6

accounted for 365 In Dianchi Lake the composition ratioof FeS declined from535 in surface to 302 in bottomwiththe increasing depths in the sediments and the fraction ofsulfate declined from 443 to 113 FeS

2was found below

the 10 cm depth and its relative proportion rapidly increasedfrom 54 to 302 in the deep layers The fraction of Sspecies with intermediate oxidation states between 0 and +6ranged from 23 to 256 in the 10ndash24 cm sediments Thecomposition of sedimentary S species in Caohai Lake andHongfeng Lake was similar to that in Dianchi Lake

In particular sediments from Qinghai Lake containeda very high proportion of sulfate with an average value of889 The proportion of the sulfate slightly decreased from


30

25

20

15

10

5

0

Dep

th (c

m)

40 60 80 1000 20Mass percentages of S compounds ()

Most reduced S

Most oxidized S

Intermediate S

(a)

Most reduced S

Most oxidized S

Intermediate S

30

25

20

15

10

5

0

Dep

th (c

m)


(b)

Figure 4 Mass percentages of most reduced S (oxidation state lt 0) intermediated S (oxidation state from 0 to +5) and most oxidized S(oxidation state +6) in the sediments from (a) Dianchi Lake and (b) Qinghai Lake

943 to 835 in the depths that ranged from 0 to 6 cmthen slightly increased from 835 to 883 in the 6ndash10 cmsediments The contribution of FeS and FeS

2was very low

while the FeS + FeS2content varied between 47 and 156 in

all samples There was no indication of other sulfur specieswith intermediate oxidation states between 0 and +6 in thecore profile of Qinghai Lake

The combination of S speciation helps to constrain thedepositional environment present in these sediments Sim-ilar percentages of most reduced S (oxidation state lt 0)intermediated S (oxidation state from 0 to +5) and mostoxidized S (oxidation state +6) in the sediments of DianchiLake and Qinghai Lake were calculated by LCF (Figure 4)Our results indicated that the ratio of most oxidized Sreduced in the surface (0ndash8 cm) sediment of Dianchi Lakecorrespondingly the proportion ofmost reduced S increasedimplying the transformation from sulfate to sulfide ironthrough a strong activity of SRB in the top layer Sulfatereduction was usually not limited by the sulfate in surfacelayers as the concentration exceeds 119870

119898for SRB [29] But

limitation may occur deeper in the sediment because sulfateusually penetrates only to lt10 cm into freshwater sedimentsdue to its low concentration [27] As shown in Figure 4(a)at a depth of 8ndash12 cm layer the proportion of most reducedS rapidly declined correspondingly the proportion of mostoxidized S increased revealing a limitation of sulfate reduc-tion and an occurrence of reoxidation of reduced S in theanaerobic condition Similar phenomenon was also found inthe sediment profile of Qinghai Lake (Figure 4(b)) In thedeeper (gt12 cm) layers intermediated S gradually occupied ahigh ratio in the total sedimentary S indicating that the SRBwas significantly reduced in those layers because if any thebacteriamediated disproportionation reactionwill lead to thetransition from the unstable intermediate S to themore stable

reduced S and sulfateThe intermediated S in deep sedimentsfound in our study was likely to be the major product ofsulfide reoxidation in the absence of microorganisms andiron ions

It should be noted that the intermediate S was stablebelow 15 cm depth in sediments from Dianchi Lake asshown in Figure 4(a) Experiments with 35S labeled S

2O3

2minus

demonstrated that S2O3

2minus was disproportionated throughoutall redox zones in the upper 10 cm where disproportion-ating bacteria were abundant in the sediments [30] Theintermediate S was not commonly found in surface layersediments because it reacted fast with Fe3+ and was furtheroxidized to sulfate Although Fe3+ oxidizes pyrite rapidly inthe sediment surface iron-oxidizing bacteria can increase theoxidation rate by several orders of magnitude [31] supplyingFe3+ for pyrite oxidation Then in the deep layers where Fe3+was not available the intermediate S might be the majorend product of pyrite reoxidation [6] Due to the absenceof microorganisms and iron ions the intermediate S cankeep stable in deep sediments which was consistent with theresults observed in our studies lakes

4 Conclusion

The vertical distributions of sulfur speciation in sedimentcores collected from five lakes of China were investigatedusing XANES spectroscopy The results showed that S in thesediment of Qinghai Lake (saline lake) had a high proportionof sulfate averaged 889due to physical weathering of water-shed rocks while S in the sediment of Taihu Lake (freshwaterlake) had a high fraction of intermediate S (365)whichmaybe the response of the agricultural nonpoint source pollutionin drainage basin The three freshwater lakes located inSouthwestern China had similar composition characteristics


of S species indicating similar sources including chemicalweathering of carbonate and atmospheric deposition In thisstudy 60ndash90 of S compounds near the surface (0ndash10 cmdepth) sediment were in the form of sulfate and FeS Indeeper layers the ratio of FeS

2and the intermediate S such

as R-SH RSOR1015840 S2O3

2minus and RSO3

minus significantly increasedsuggesting rapid processes of sulfate reduction and sulfidereoxidation with the increasing depths Our results showthat K-Edge XANES spectroscopy has unique advantagesin morphological analysis of sulfur in sediments XANEShas provided an important analysis tool in the study of thegeochemical cycle of sulfur in the aquatic ecosystem

Competing Interests

The authors declared that there are no competing interestsrelated to this paper

Acknowledgments

This work was supported by the Chinese NSF projects (no41403113 and no 41303097) the Environmental Science andTechnology Project and the Major Application of BasicResearch Project of Guizhou Province ([2015]2001)

References

[1] N Risgaard-Petersen A Revil P Meister and L P NielsenldquoSulfur iron and calcium cycling associated with natural elec-tric currents running through marine sedimentrdquo Geochimica etCosmochimica Acta vol 92 pp 1ndash13 2012

[2] G Billon B Ouddane and A Boughriet ldquoChemical speciationof sulfur compounds in surface sediments from three bays(Fresnaye Seine and Authie) in northern France and identi-fication of some factors controlling their generationrdquo Talantavol 53 no 5 pp 971ndash981 2001

[3] G E Likens C T Driscoll D C Buso et al ldquoThe biogeochem-istry of sulfur at Hubbard Brookrdquo Biogeochemistry vol 60 no3 pp 235ndash316 2002

[4] J W Morse F J Millero J C Cornwell and D Rickard ldquoThechemistry of the hydrogen sulfide and iron sulfide systems innatural watersrdquo Earth Science Reviews vol 24 no 1 pp 1ndash421987

[5] R A Berner and R Raiswell ldquoBurial of organic carbon andpyrite sulfur in sediments over phanerozoic time a new theoryrdquoGeochimica et Cosmochimica Acta vol 47 no 5 pp 855ndash8621983

[6] G W Luther III T G Ferdelman J E Kostka E J Tsamakisand T M Church ldquoTemporal and spatial variability of reducedsulfur species (FeS

2 S2O2minus3) and porewater parameters in salt

marsh sedimentsrdquoBiogeochemistry vol 14 no 1 pp 57ndash88 1991[7] G W Luther III ldquoPyrite oxidation and reduction molecular

orbital theory considerationsrdquo Geochimica et CosmochimicaActa vol 51 no 12 pp 3193ndash3199 1987

[8] D Rickard ldquoKinetics of pyrite formation by the H2S oxidation

of iron (II) monosulfide in aqueous solutions between 25 and125∘C the rate equationrdquoGeochimica et CosmochimicaActa vol61 no 1 pp 115ndash134 1997

[9] L Holmkvist T G Ferdelman and B B Joslashrgensen ldquoA crypticsulfur cycle driven by iron in the methane zone of marine sed-iment (Aarhus Bay Denmark)rdquo Geochimica et CosmochimicaActa vol 75 no 12 pp 3581ndash3599 2011

[10] J Prietzel A Botzaki N TyufekchievaM Brettholle JThiemeandW Klysubun ldquoSulfur speciation in soil by S K-edge XANESspectroscopy comparison of spectral deconvolution and linearcombination fittingrdquo Environmental Science and Technologyvol 45 no 7 pp 2878ndash2886 2011

[11] J Prietzel J Thieme U Neuhausler J Susini and I Kogel-Knabner ldquoSpeciation of sulphur in soils and soil particles byX-ray spectromicroscopyrdquo European Journal of Soil Science vol54 no 2 pp 423ndash433 2003

[12] F Jalilehvand ldquoSulfur not a lsquosilentrsquo element anymorerdquoChemicalSociety Reviews vol 35 no 12 pp 1256ndash1268 2006

[13] E Lombi and J Susini ldquoSynchrotron-based techniques forplant and soil science opportunities challenges and futureperspectivesrdquo Plant and Soil vol 320 no 1-2 pp 1ndash35 2009

[14] D Solomon J Lehmann and C E Martınez ldquoSulfur K-edge XANES spectroscopy as a tool for understanding sulfurdynamics in soil organic matterrdquo Soil Science Society of AmericaJournal vol 67 no 6 pp 1721ndash1731 2003

[15] J Prietzel J Thieme N Tyufekchieva D Paterson I McNultyand I Kogel-Knabner ldquoSulfur speciation in well-aerated andwetland soils in a forested catchment assessed by sulfur S K-edge X absorption near-edge spectroscopy (XANES)rdquo Journalof Plant Nutrition and Soil Science vol 172 no 3 pp 393ndash4032009

[16] A Shchukarev V Galman J Rydberg S Sjoberg and IRenberg ldquoSpeciation of iron and sulphur in seasonal layersof varved lake sediment an XPS studyrdquo Surface and InterfaceAnalysis vol 40 no 3-4 pp 354ndash357 2008

[17] B C Bostick K M Theissen R B Dunbar and M AVairavamurthy ldquoRecord of redox status in laminated sedimentsfrom Lake Titicaca a sulfur K-edge X-ray absorption near edgestructure (XANES) studyrdquo Chemical Geology vol 219 no 1ndash4pp 163ndash174 2005

[18] Z D Jin Y M Han and L Chen ldquoPast atmospheric Pbdeposition in Lake Qinghai northeastern Tibetan PlateaurdquoJournal of Paleolimnology vol 43 no 3 pp 551ndash563 2010

[19] A-M Zhou D-S Wang and H-X Tang ldquoPhosphorus frac-tionation and bio-availability in Taihu Lake (China) sedimentsrdquoJournal of Environmental Sciences vol 17 no 3 pp 384ndash3882005

[20] J G Li R P Philp PU Fan and J Allen ldquoLong-chain alkenonesin Qinghai Lake sedimentsrdquo Geochimica et Cosmochimica Actavol 60 no 2 pp 235ndash241 1996

[21] Z D Jin JM Yu SMWang F Zhang YW Shi andC-F YouldquoConstraints on water chemistry by chemical weathering in theLakeQinghai catchment northeasternTibetanPlateau (China)clues from Sr and its isotopic geochemistryrdquo HydrogeologyJournal vol 17 no 8 pp 2037ndash2048 2009

[22] Q M Li W Zhang X X Wang Y Y Zhou H Yang and G LJi ldquoPhosphorus in interstitial water induced by redox potentialin sediment of Dianchi Lake Chinardquo Pedosphere vol 17 no 6pp 739ndash746 2007

[23] F CWuH RQing andG JWan ldquoRegeneration ofN P and SiNear the sedimentwater interface of lakes from SouthwesternChina Plateaurdquo Water Research vol 35 no 5 pp 1334ndash13372001

[24] B R Davies M C Thoms K F Walker J H OrsquoKeefeand J A Gore ldquoDryland rivers their ecology conservation


and managementrdquo in The Rivers Handbook Hydrological andEcological Principles P Calow and G E Petts Eds BlackwellScience Cambridge UK 1996

[25] S Peiffer ldquoGeochemical and microbial processes in sedimentsand at the sedimentwater interface of acidic mining lakesrdquoWater Air and Soil Pollution vol 108 no 3-4 pp 227ndash229 1998

[26] T Larssen E Lydersen D Tang et al ldquoAcid rain in ChinardquoEnvironmental Science and Technology vol 40 no 2 pp 418ndash425 2006

[27] M Holmer and P Storkholm ldquoSulphate reduction and sulphurcycling in lake sediments a reviewrdquo Freshwater Biology vol 46no 4 pp 431ndash451 2001

[28] A J C Sinke A A Cornelese T E Cappenberg and A J BZehnder ldquoSeasonal variation in sulfate reduction andmethano-genesis in peaty sediments of eutrophic Lake Loosdrecht TheNetherlandsrdquo Biogeochemistry vol 16 no 1 pp 43ndash61 1992

[29] MDornblaser A E Giblin B Fry and B J Peterson ldquoEffects ofsulfate concentration in the overlyingwater on sulfate reductionand sulfur storage in lake sedimentsrdquo Biogeochemistry vol 24no 3 pp 129ndash144 1994

[30] B B Jorgensen and F Bak ldquoPathways and microbiology ofthiosulfate transformations and sulfate reduction in a marinesediment (Kattegat Denmark)rdquo Applied and EnvironmentalMicrobiology vol 57 no 3 pp 847ndash856 1991

[31] S FMa and J F Banfield ldquoMicron-scale Fe2+Fe3+ intermediatesulfur species and O

2gradients across the biofilmndashsolutionndash

sediment interface control biofilm organizationrdquo Geochimica etCosmochimica Acta vol 75 no 12 pp 3568ndash3580 2011

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Inorganic ChemistryInternational Journal of

Hindawi Publishing Corporation httpwwwhindawicom Volume 2014

International Journal ofPhotoenergy


Carbohydrate Chemistry

International Journal of


Journal of

Chemistry


Advances in

Physical Chemistry

Hindawi Publishing Corporationhttpwwwhindawicom

Analytical Methods in Chemistry

Journal of

Volume 2014

Bioinorganic Chemistry and ApplicationsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

SpectroscopyInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Medicinal ChemistryInternational Journal of


Chromatography Research International


Applied ChemistryJournal of



Theoretical ChemistryJournal of


Journal of

Spectroscopy

Analytical ChemistryInternational Journal of


Journal of


Quantum Chemistry


Organic Chemistry International

ElectrochemistryInternational Journal of



CatalystsJournal of


Beijing

Qinghai Lake

Taihu Lake

Dianchi Lake

Caohai LakeHongfeng Lake

N

QH

TH

HF

CH

DC

0 1000(km)

0 10(km)

0 5(km)

0 20(km)

0 30(km)

0 60(km)

20∘

30∘

40∘

90∘E 100

∘110

∘120

∘

Figure 1 Location of the studied lakes

Hongfeng Lake (Southwest China) Caohai Lake (SouthwestChina) and Dianchi Lake (Southwest China) The objectis to understand the S speciation and its transformation insediments of the terrestrial aquatic ecosystems

2 Materials and Methods

21 Area Description In this study five lakes were chosenbased on economic and geographic status in the YangtzeRiver region Southwest Plateau and Qinghai-Tibet PlateauChina (Figure 1) Geographic and limnological features forthe five selected lakes are shown in Table 1 [18 22] TaihuLake is the third largest freshwater lake in China locatedat the downstream of the Changjiang River More than 200brooks canals and rivers discharge industrial wastewatermostly from nearby cities into the lake Many effluents con-tain pesticides toxic chemicals or heavy metals SouthwestPlateau China is the largest karst area in China Accordingto previous lake chemistry surveys [23] one slightly pollutedlake (Caohai Lake) and two heavily polluted lakes (DianchiandHongfeng Lakes)were selected in this areaQinghai Lakea closed-basin lake is the largest inland saline lake in ChinaThe amount of evaporation (sim1400mmyear) is in excess ofthe mean annual precipitation (sim400mmyear) resulting inthe development of a saline lake

22 Sampling Procedures Sediment core samples wereobtained from the five lakes in September 2013 nearly inthe centre of the lakes A plastic static gravity corer with

30 cm length and 6 cm diameter Plexiglas cylinder tube wasemployed to obtain the sediment cores The core sampleswere sliced with intervals of 2 cm with the exception of thecore from Qinghai Lake sectioned at 1 cm intervals Sedi-ments were handled under protective nitrogen atmospheres(purity 999 Guiyang Shenjian Gas Co Ltd) All sampleswere put in sealed plastic bag and immediately transferredto laboratory in iceboxes (lt4∘C) and freeze-dried After thatthe samples were frozen with liquid nitrogen Before XANESanalysis dry samples were ground and sieved with a standard100-mesh sieve

23 Sulfur K-Edge XANES The sulfur K-edge XANES spec-tra were recorded at 4B7A beamline (medium X-ray beam-line 2100ndash6000 eV) using synchrotron radiation from BeijingSynchrotron Radiation Facility the Institute of High EnergyPhysics the Chinese Academy of Sciences The samples werepressed into thin films before analysis The storage ring wasoperated at the energy of 25 GeVwith Si (111) double crystalsSpectra were scanned at step widths of 03 eV in the regionbetween 2420 and 2520 eV with fluorescence mode usinga fluorescent ion chamber Si (Li) detector (PGT LS30135)Additional filters were placed between the sample and thedetector to reduce the fluorescence signal derived from Si inthe samples

Fe monosulfide (FeS) pyrite (FeS2) R-SH RSOR1015840

Na2SO3 NaRSO

3 and Na

2SO4were chosen as the standard

compounds Electronic oxidation states white-line energiesand intensities of reference S compounds were shown in





26∘251015840ndash341015840N106∘201015840ndash281015840E

24∘401015840ndash25∘021015840N102∘361015840ndash∘471015840E

26∘491015840ndash531015840N104∘121015840ndash181015840E

36∘321015840ndash37∘151015840N99∘361015840ndash100∘471015840E






Warmsemihumid








2) and another near






White-lineintensity



+368 24784 203NaRSO

3+5 24812 233

Na2SO4

+6 24826 254


2O3

2minus


2and

















2




0000

0002

0004

0006

0008

0010

0012

Inte

nsity

0ndash2 cm3-4 cm

(a) Taihu Lake

000

002

004

006

008

010

012

Inte

nsity


9-10 cm0-1 cm

(b) Qinghai Lake


000

002

004

006

008

010

012

Inte

nsity

0ndash2 cm

21-22 cm11-12 cm

(c) Dianchi Lake

000

002

004

006

008

010

012

Inte

nsity



(d) Caohai Lake

000

002

004

006

008

010

012

Inte

nsity



(e) Hongfeng Lake



Taihu Lake

Caohai Lake

Hongfeng Lake

Qinghai Lake

Dianchi Lake


22

18

14

10

6

2

Dep

th (c

m)

10

7

4

1

Dep

th (c

m)


2

Dep

th (c

m) 40 60 80 1000 20


14

10

6

2

Dep

th (c

m)



22

18

14

10

6

2

Dep

th (c

m)

FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus


3

2minus RSO3

minus and SO4






2 and FeS



2was found below




30

25

20

15

10

5

0

Dep

th (c

m)


Most reduced S

Most oxidized S

Intermediate S

(a)

Most reduced S

Most oxidized S

Intermediate S

30

25

20

15

10

5

0

Dep

th (c

m)


(b)



2was very low








2O3

2minus



4 Conclusion






2minus and RSO3


Competing Interests


Acknowledgments


References
















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





26∘251015840ndash341015840N106∘201015840ndash281015840E

24∘401015840ndash25∘021015840N102∘361015840ndash∘471015840E

26∘491015840ndash531015840N104∘121015840ndash181015840E

36∘321015840ndash37∘151015840N99∘361015840ndash100∘471015840E






Warmsemihumid








2) and another near






White-lineintensity



+368 24784 203NaRSO

3+5 24812 233

Na2SO4

+6 24826 254


2O3

2minus


2and

















2




0000

0002

0004

0006

0008

0010

0012

Inte

nsity

0ndash2 cm3-4 cm

(a) Taihu Lake

000

002

004

006

008

010

012

Inte

nsity


9-10 cm0-1 cm

(b) Qinghai Lake


000

002

004

006

008

010

012

Inte

nsity

0ndash2 cm

21-22 cm11-12 cm

(c) Dianchi Lake

000

002

004

006

008

010

012

Inte

nsity



(d) Caohai Lake

000

002

004

006

008

010

012

Inte

nsity



(e) Hongfeng Lake



Taihu Lake

Caohai Lake

Hongfeng Lake

Qinghai Lake

Dianchi Lake


22

18

14

10

6

2

Dep

th (c

m)

10

7

4

1

Dep

th (c

m)


2

Dep

th (c

m) 40 60 80 1000 20


14

10

6

2

Dep

th (c

m)



22

18

14

10

6

2

Dep

th (c

m)

FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus


3

2minus RSO3

minus and SO4






2 and FeS



2was found below




30

25

20

15

10

5

0

Dep

th (c

m)


Most reduced S

Most oxidized S

Intermediate S

(a)

Most reduced S

Most oxidized S

Intermediate S

30

25

20

15

10

5

0

Dep

th (c

m)


(b)



2was very low








2O3

2minus



4 Conclusion






2minus and RSO3


Competing Interests


Acknowledgments


References
















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of














2




0000

0002

0004

0006

0008

0010

0012

Inte

nsity

0ndash2 cm3-4 cm

(a) Taihu Lake

000

002

004

006

008

010

012

Inte

nsity


9-10 cm0-1 cm

(b) Qinghai Lake


000

002

004

006

008

010

012

Inte

nsity

0ndash2 cm

21-22 cm11-12 cm

(c) Dianchi Lake

000

002

004

006

008

010

012

Inte

nsity



(d) Caohai Lake

000

002

004

006

008

010

012

Inte

nsity



(e) Hongfeng Lake



Taihu Lake

Caohai Lake

Hongfeng Lake

Qinghai Lake

Dianchi Lake


22

18

14

10

6

2

Dep

th (c

m)

10

7

4

1

Dep

th (c

m)


2

Dep

th (c

m) 40 60 80 1000 20


14

10

6

2

Dep

th (c

m)



22

18

14

10

6

2

Dep

th (c

m)

FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus


3

2minus RSO3

minus and SO4






2 and FeS



2was found below




30

25

20

15

10

5

0

Dep

th (c

m)


Most reduced S

Most oxidized S

Intermediate S

(a)

Most reduced S

Most oxidized S

Intermediate S

30

25

20

15

10

5

0

Dep

th (c

m)


(b)



2was very low








2O3

2minus



4 Conclusion






2minus and RSO3


Competing Interests


Acknowledgments


References
















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of



0000

0002

0004

0006

0008

0010

0012

Inte

nsity

0ndash2 cm3-4 cm

(a) Taihu Lake

000

002

004

006

008

010

012

Inte

nsity


9-10 cm0-1 cm

(b) Qinghai Lake


000

002

004

006

008

010

012

Inte

nsity

0ndash2 cm

21-22 cm11-12 cm

(c) Dianchi Lake

000

002

004

006

008

010

012

Inte

nsity



(d) Caohai Lake

000

002

004

006

008

010

012

Inte

nsity



(e) Hongfeng Lake



Taihu Lake

Caohai Lake

Hongfeng Lake

Qinghai Lake

Dianchi Lake


22

18

14

10

6

2

Dep

th (c

m)

10

7

4

1

Dep

th (c

m)


2

Dep

th (c

m) 40 60 80 1000 20


14

10

6

2

Dep

th (c

m)



22

18

14

10

6

2

Dep

th (c

m)

FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus


3

2minus RSO3

minus and SO4






2 and FeS



2was found below




30

25

20

15

10

5

0

Dep

th (c

m)


Most reduced S

Most oxidized S

Intermediate S

(a)

Most reduced S

Most oxidized S

Intermediate S

30

25

20

15

10

5

0

Dep

th (c

m)


(b)



2was very low








2O3

2minus



4 Conclusion






2minus and RSO3


Competing Interests


Acknowledgments


References
















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


Taihu Lake

Caohai Lake

Hongfeng Lake

Qinghai Lake

Dianchi Lake


22

18

14

10

6

2

Dep

th (c

m)

10

7

4

1

Dep

th (c

m)


2

Dep

th (c

m) 40 60 80 1000 20


14

10

6

2

Dep

th (c

m)



22

18

14

10

6

2

Dep

th (c

m)

FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus FeS

R-SHFeS2

RSOR998400

SO42minus

RSO3minus

S2O32minus


3

2minus RSO3

minus and SO4






2 and FeS



2was found below




30

25

20

15

10

5

0

Dep

th (c

m)


Most reduced S

Most oxidized S

Intermediate S

(a)

Most reduced S

Most oxidized S

Intermediate S

30

25

20

15

10

5

0

Dep

th (c

m)


(b)



2was very low








2O3

2minus



4 Conclusion






2minus and RSO3


Competing Interests


Acknowledgments


References
















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of


30

25

20

15

10

5

0

Dep

th (c

m)


Most reduced S

Most oxidized S

Intermediate S

(a)

Most reduced S

Most oxidized S

Intermediate S

30

25

20

15

10

5

0

Dep

th (c

m)


(b)



2was very low








2O3

2minus



4 Conclusion






2minus and RSO3


Competing Interests


Acknowledgments


References
















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





2minus and RSO3


Competing Interests


Acknowledgments


References
















































Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of





















Journal of

Chemistry


Advances in

Physical Chemistry



Journal of

Volume 2014














Journal of

Spectroscopy



Journal of


Quantum Chemistry






CatalystsJournal of

research article sulfur speciation in the surface...

Documents