Applications of Organic and Inorganic Amendments Induce Changes in the Mobility of Mercury and...

Research ArticleApplications of Organic and Inorganic AmendmentsInduce Changes in the Mobility of Mercury and Macro- andMicronutrients of Soils

Mercedes Garciacutea-Saacutenchez Adeacutela Šiacutepkovaacute Jilina Szaacutekovaacute Lukaacuteš KaplanPavla Ochecovaacute and Pavel Tlustoš

Department of Agro-Environmental Chemistry and Plant Nutrition Faculty of Agrobiology Food and Natural ResourcesCzech University of Life Sciences Suchdol 16521 Prague 6 Czech Republic

Correspondence should be addressed to Jirina Szakova szakovaafczucz

Received 11 June 2014 Revised 3 September 2014 Accepted 24 September 2014 Published 23 October 2014

Academic Editor Antonio Paz Gonzalez

Copyright copy 2014 Mercedes Garcıa-Sanchez et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Both soil organic matter and sulfur (S) can reduce or even suppress mercury (Hg) mobility and bioavailability in soil A batchincubation experiment was conducted with a Chernozem and a Luvisol artificially contaminated by 440mgsdotkgminus1Hg showingwide differences in their physicochemical properties and available nutrients The individual treatments were (i) digestate fromthe anaerobic fermentation of biowaste (ii) fly ash from wood chip combustion and (iii) ammonium sulfate and every treatmentwas added with the same amount of S The mobile Hg portion in Chernozem was highly reduced by adding digestate even after1 day of incubation compared to control Meanwhile the outcome of these treatments was a decrease of mobile Hg forms as afunction of incubation time whereas the contents of magnesium (Mg) potassium (K) iron (Fe) manganese (Mn) copper (Cu)zinc (Zn) and phosphorus (P) were stimulated by the addition of digestate in both soils The available calcium (Ca) contents werenot affected by the digestate addition The experiment proved digestate application as the efficient measure for fast reduction ofmobile Hg at extremely contaminated soils Moreover the decrease of the mobile mercury portion was followed by improvementof the nutrient status of the soils

1 Introduction

Industrial activities have increased the proportion of Hgin the atmosphere and oceans and have contaminated anumber of local environments [1] From the ecotoxicologicalpoint of view critical limits of Hg (given as soil elementcontents above which unacceptable effects are expected) aresubstantially lower than values derived for other metals suchas Cd Cu Ni Pb and Zn [2] Li et al [3] compared themobil-ity and plant-availability of risk elements from industriallycontaminated soil where the soil-to-plant transfer coefficientswere in the order of CdgtZngtCugtHggtAsgtPb confirmingthe relatively low availability of soil Hg for various vegetablesRodrigues et al [4] observed the water-soluble contents ofHgin highly contaminated sediment and soil samples (total Hgcontents even higher than 3000mgsdotkgminus1) to be less than 12of the total Hg content Boszke et al [5] classified the divalent

and elemental Hg bounds to humic matterorganic matter asthe ldquosemimobilerdquo element portion and observed low portionsof the water-soluble Hg species as well

Luo et al [6] suggested that soil organic matter andnitrogen were the important sinks for Hg in the soils Thegood capacity of Hg for adsorption and complexation inthe solid media resulted in limited bioaccessibility of thiselement whichwas reported byHassen et al [7] Distributioncoefficients forHg2+ binding by humic acidswere determinedbyKhwaja et al [8] confirming that the calculated concentra-tion of freeHg2+ at equilibrium is very lowAlsoHeeraman etal [9] observed decreasing Hgmobility and plant-availabilityin the organic matter-treated soil The importance of soilorganicmatter forHgmobility and bioavailability in soil sam-ples is known andwell described [5 10] As observed byYao etal [11] the addition of humus can either suppress or promoteHg bioavailability depending on the soil composition In

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 407049 11 pageshttpdxdoiorg1011552014407049

2 The Scientific World Journal

this context the effect of a particular humus fraction on Hgbioavailability is related to its ability to convert Hg bound bysolid phases into soluble complexes as well as the stabilityof the released complexes On the contrary the presenceof dissolved organic matter (DOM) can significantly reducemaximum Hg adsorption capacity and even promote Hgdesorption from the soils [12]

Zagury et al [13] evaluated the potential mobility andplant-availability of Hg in the highly contaminated soilsby chlor-alkali plants where the total Hg contents in soilreached up to 11500mgsdotkgminus1 Although the water extractableHg portion was relatively low with regard to the high totalcontent it represented significant concentrations correlatingwith Hg uptake by experimental plants

Reis et al [14] observed that the presence of Hg in themobile phase could be related to Mn and aluminum (Al) soilcontents A positive relation between Hg in the semimobilefraction and the Al content was also observed On the con-trary organic matter and S contents contributed to Hgretention in the soil matrix reducing the mobility of themetal Sulfide minerals are known to be effective adsorbentsfor Hg(II) being the primary sink for Hg in the environment[15] In this context Hesterberg et al [16] demonstrated thepreferential binding of Hg(II) to reduced organic S sites Sub-sequently similar observations were provided and describedin soils as mentioned by Remy et al [17] Concentration ofMeHg is negatively correlated with soil total organic matterand total S and is influenced by the soil totalHg concentration[17] Akerblom et al [18] highlighted that long-term chronicSO4

2minus deposition at rates similar to those found in pollutedareas of Europe and North America increase the capacityof peatlands to methylate Hg and store MeHg Competitiverelationships between Hg and other metals in soil wereobserved by Jing et al [19] where desorption of adsorbed Hgincreased with elevated concentrations of added Cu or Zn

In our investigation a laboratory batch incubation exper-iment was conducted with Chernozem and Luvisol differingin their physicochemical parameters and the available nutri-ent contents Digestate the bio-waste originating from biogasproduction plants was applied as a S-rich source of organicmatter Alternatively wood ash from biomass combustionplants was applied as a different source of S and other macro-and micronutrients As proven by Ochecova et al [20] theplant-availability of the risk elements in the contaminated soildecreased after ash application whereas the nutrient contentstended to increase To separate the effect of organic matterand S in the soil inorganic source of S ammonium sulfate(NH4

)2

SO4

was applied as well The main objectives of thestudy were as follows (i) to assess the ability of the individualtreatments to immobilize Hg in the artificially contaminatedsoil and (ii) to evaluate the potential interactions betweenHg sorption in the experimental soil and the mobility of theessential macro- and microelements in these soils

2 Materials and Methods

21 Soils and Ameliorative Materials The following twosoils differing in their physicochemical characteristics were

Table 1 Main physicochemical characteristics of the experimentalsoils

Soil type Luvisol ChernozemNRSC Soil Texture Silt loam Silt loamClay (lt0002mm) [] 538 218Silt (0002ndash005mm) [] 6814 7180Sand (005ndash2mm) [] 2648 2603

Location 50∘410158402210158401015840N14∘1010158401910158401015840E

50∘710158404010158401015840N14∘2210158403310158401015840E

Altitude (m asl) 410 286P Mehlich IIIlowast (mg kgminus1) 100 91K Mehlich IIIlowast (mg kgminus1) 80 230Mg Mehlich IIIlowast (mg kgminus1) 110 240Ca Mehlich IIIlowast (mg kgminus1) 3600 9000lowastSıpkova et al [23]

selected for the experiment (i) uncontaminated Chernozemwith a cation exchange capacity (CEC) of 230mmol kgminus1a pH level of 75 and an oxidizable carbon content (Cox)of 26 and (ii) uncontaminated Luvisol with a CEC of145mmol kgminus1 a pH level of 65 and a Cox of 17 Nutrientcontents and other characteristics in both soil samples aresummarized in Table 1 Soils were sampled from a depthof 20 cm immediately after which they were homogenizedsieved through a 5mm diameter mesh and kept at roomtemperature For the experimental incubation soils sampleswere sieved again using a 2mm mesh and kept at 4∘C untiluse The fly ash (pH 121) was produced by the combustion ofwood ash produced in two reactors (18MW and 06MW)The digestate sample (pH 82) originated from a biogasstation (1732 kWh) where the digested material consistedof sugar beet pulp (50) marc of fruit (42) and silagemaize (8) The macro- and micronutrient contents in bothameliorative materials are summarized in Table 2 As aninorganic amendment solid particles of (NH

4

)2

SO4

wereused (Reagent from Fisher Scientific)

22 Experimental Design For the experimental incubationsoils 100 g of Chernozem and Luvisol soils were placed intopolypropylene bottles and immediately after were brought to60 moisture saturation Then half of the soil samples wereartificially contaminated with Hg by adding 60mg of HgCl

2

to reach a concentration of 440mgsdotkgminus1 of Hg Subsequentlyorganic and inorganic amendments (1) ash (2) digestateand (3) (NH

4

)2

SO4

were applied both to contaminatedand noncontaminated soils The rate of amendment wascalculated for 600mg S per kg of soil as follows (1) ash 15 g(2) digestate 10 g and (3) NH

4

SO4

025 g per bottleSoils that were contaminated and noncontaminated with

Hg were thoroughly mixed and incubated at 28∘C for 21 daysTo evaluate the mobility of Hg in both soils and interactionswith macro- and micronutrients as well soil samples werecollected after 1 2 3 4 7 14 and 21 days of incubationThreereplicates were set up per treatment

The Scientific World Journal 3

Table 2 Nutrient contents in the dry matter of ameliorativematerials

Element Fly-ash DigestateP () 129 plusmn 001 120 plusmn 001K () 774 plusmn 002 212 plusmn 001Mg () 144 plusmn 002 049 plusmn 002Ca () 134 plusmn 01 315 plusmn 001S () 407 plusmn 001 060 plusmn 001Cu () 0020 plusmn 0001 0004 plusmn 0001Fe () 279 plusmn 001 018 plusmn 001Mn () 129 plusmn 001 002 plusmn 000Zn () 358 plusmn 008 003 plusmn 000

23 Extraction of Soluble Portions of Hg and Macro- andMicronutrients For the determination of bioavailable ele-ment portions in soils during the experiment 05 g ofeach sample was added to 10mL of 011mol Lminus1 solutionof CH

3

COOH and shaken overnight [21] Each extractionwas carried out in three replicates For the centrifugation ofextracts a Hettich Universal 30 RF (Germany) instrumentwas used The reaction mixture was centrifuged at 3000 rpm(ie 460 g) for 10 minutes at the end of each extraction pro-cedure and the supernatants were kept at 6∘C prior to mea-surements Prior to the analysis extracts were acidified with amixture of acids (HNO

3

HCl = 3 1) For the determinationof nutrient status in the experimental soils before the exper-iment the Mehlich III extraction procedure (02mol Lminus1 ofCH3

COOH + 025mol Lminus1 of NH4

NO3

+ 0013mol Lminus1 ofHNO

3

+ 0015mol Lminus1 of NH4

F + 0001mol Lminus1 of EDTA) atthe ratio of 1 g of soil per 10mL of the extraction mixture for10min [22] was applied

24 Determination of Hg Hg content in the extracts wasmeasured by inductively coupled plasma mass spectrometry(ICP-MS Agilent 7700x Agilent Technologies Inc USA)The auto-samplerASX-500 a three-channel peristaltic pumpand MicroMist nebulizer equipped the ICP-MS Calibrationsolutions were prepared in diluted single element ICP-MSstandards as 01ndash100120583g Lminus1 for Hg and the isotope Hg(202)was measured As an internal standard Pt(195) was used atthe concentration of 100 120583g Lminus1

25 Determination ofMacro- andMicronutrients Inductivelycoupled plasma-atomic emission spectrometry (ICP-OESAgilent 720 Agilent Technologies Inc USA) equipped witha two-channel peristaltic pump a Struman-Masters spraychamber and a V-groove pneumatic nebulizer made of inertmaterial was applied for the determination of Cu Fe MnZn P and S in the extracts (the experimental conditionswere as follows power of 12 kW plasma flow of 150 Lsdotminminus1auxiliary flow of 075 Lsdotminminus1 nebulizer flow of 09 Lsdotminminus1)whereas flame atomic absorption spectrometry (F-AAS Var-ian 280FS Varian Australia air flow of 135 Lsdotminminus1 acety-lene flow of 22 Lsdotminminus1 burner height of 135mL nebulizeruptake rate of 5mLsdotminminus1) was used for Ca Mg and Kdetermination in the extracts

26 Determination of Total Nutrient Contents in the Amelio-rative Materials For determination of total element contentsin the ash nondestructive X-ray fluorescence (XRF) spec-trometry (Spectro IQ Kleve Germany) was used the targetmaterial was palladium and the target angle from the centralray was 90∘ The focal point was a 1mm times 1mm squareand the maximum anode dissipation was 50W with 10 cfmforced-air cooling The instrument was equipped with theBarkla crystal HOPG The tested samples were pressed intopellets this involved mixing 40 g of ash (particle size 15ndash20120583m) with 09 g of the binding additive (HWC Hoechstwax Germany) for 10min with a pressing power of 80 kNThe determination was performed in the Institute of RockStructure and Mechanics Academy of Sciences of the CzechRepublic

The digestate sample was decomposed by pressurizedwet ashing as follows aliquots (sim05 g) of air-dried sampleswere decomposed in a digestion vessel with 10mL of Aquaregia (ie nitric and hydrochloric acid mixture in the ratio1 3) The mixture was heated in an Ethos 1 (MLS Germany)microwave assisted wet digestion system for 33min at 210∘CICP-OES and F-AAS were then applied as described in theprevious subchapter

27 Statistics The data obtained were subjected to Dixonrsquostest for the identification of outliers (significance level 120572 =005) using Microsoft Office Excel 2007 (Microsoft Corpora-tion USA) Subsequently one-way analysis of variance wasused at the significance level 120572 = 005 using the Statistica 12program (StatSoft USA)

3 Results and Discussion

31 Changes in Hg Mobility in the Treated Soils The mobileHg contents affected by the individual treatments and theirvariability during the incubation experiment are summarizedin Figure 1 In the treatments without artificial Hg appli-cation the mobile Hg contents were under the detectionlimit of ICP-MS Similarly to our previous observations [23]Ruggiero et al [24] also documented that most of the Hgin the long-term polluted soils was scarcely mobile andavailableTheHg contents in digestates and fly ash are usuallylow as well [25 26] and did not affect the mobile portions ofHg in our experiment The extractable Hg contents differedaccording to the physicochemical parameters of the usedsoils and to the individual treatments In Chernozem theextractable Hg contents were low regardless of the treatmentat the beginning and end of incubation Within the 3rd and7th day of incubation themobile Hg portions increased in alltreatments (including control) except for the digestate Simi-lar course of Hg mobility changes were observed by Bower etal [27] in the experiments studying the mercury adsorptiononto pyrite indicating the formation of nonmobile sulfidesover time In the Luvisol the mobile Hg portions decreasedduring the incubation whereas they dropped to the levelsreached in Chernozem by the end of the experiment Asstated by Muller et al [28] soil Hg contamination cancause reduced microbial biomass at the contaminated sites


0

20

40

60

80

100

1 6 11 16 21

Incubation time (days)

Chernozem

ControlAsh

0

2

4

6

8

0

100

200

300

400

1 6 11 16 21


Luvisol

Digestate(NH4)2SO4

ControlAsh Digestate

(NH4)2SO4

Exce

pt d

iges

tate

(mgmiddot

kgminus1)

Exce

pt d

iges

tate

(mgmiddot

kgminus1)

Dig

esta

te (m

gmiddotkg

minus1)

Dig

esta

te (m

gmiddotkg

minus1)

080

060

040

020

000

Figure 1 The concentrations of Hg extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) according to theindividual treatments

However somemicroorganisms have developedmechanismsto adapt to Hg that is Hg-resistant bacteria Thus thechanges in Hg mobility observed throughout the experimentcould be partially attributed to different communities of soilmicroorganism present in both Chernozem and Luvisol

Therefore among the individual treatments digestatewas shown to be the most effective Hg immobilizing agentwhereas fly ash seemed to be less effective and no significantdifference was reported comparing the ammonium sulfatetreatment and untreated control except the faster increaseof mobile Hg content in 3rd and 4th days of the incubationindicating potential role of increased portion ofmobile sulfuras mentioned below The effectiveness of individual treat-ments as well as the temporal changes in mobile Hg portionswere also affected predominantly by the soil where highersorption capacity and organic matter content in Chernozemresulted in lower mobile portions of Hg in all the treatmentsexcept increased mobility of Hg after ash application in 7thand 14th day of the incubation These results also indicatedthat S content in the ameliorative materials was not the mainfactor controlling the Hg mobility in the soils Luo et al [6]reported a low relationship between S and Hg contents insoils with low total organic carbon (sim2) as in our casewhere the carbon contentwas not increased by the addition ofammonium sulfate and ash In the opposite theHg behaviourin soils strongly differed if digestate with high content of bothS and total carbon content was applied

Higher organic carbon content in the soil can enhanceboth soil microbial activities and the retention of total Hgand MeHg in soil [29] Soil microorganisms need essentialmetals for their metabolism which are often required in lowconcentrations and act as enzyme cofactors [30] Thereforehigh contents of macro- and micronutrients in both ash anddigestate (Table 2) can be beneficial for the enhancementof the microbial activity in soils Limited Hg mobility viacomplexation with soil organic matter was already described[9] Ravichandran [31] reviewed the formation of extremelystrong ionic bonds between Hg and reduced S sites in soilorganic matter supporting the importance of the mutual roleof S and organic matter in Hg immobilization in soil

Therefore the Hg desorption increased with elevating con-centrations of dissolved organic matter [10] In our case thedissolved organic matter after 1 day of incubation variedbetween 719mgsdotkgminus1 (control) and 1070mgsdotkgminus1 (diges-tate) in Chernozem and between 212mgsdotkgminus1 (control) and564mgsdotkgminus1(digestate) in Luvisol After 7 days of incubationthe DOM contents increased even 22-fold in the digestate-treated Luvisol whereas the maximum 15-fold increase wasobserved in Chernozem Therefore our results indicate thatmore complex factors can change the Hgmobility in soil thansolely the content and solubility of organic carbon in soil Forexample the affinity of Hg to bind to metal oxides should betaken into account [32] Also the role of some soil bacteriawhich are able to degrade Hg compounds into metallic Hg bythe action of specific enzymes encoded by themer genes andthen be released into the surrounding environment shouldbe considered [33] Thus the decrease of mobile Hg in soilcould be partially figured in the volatilization of this elementduring incubationThis assumption remains to be verified infurther research In our investigation the experiments wereconcerned on the description of potential decrease of mobileHg content without exact resolution between immobiliza-tionvolatilization ratios after the individual treatments

32 The Effect of Hg andor Ameliorative Materials on MobileContents ofMacro- andMicronutrients in the Soil Themobilemacro- andmicroelement contents affected by the individualtreatments andor duration of incubation are summarized inTables 3 4 5 6 7 8 9 10 and 11 The presence of digestateshowed a predominant effect on the mobile portions of mostof the elements among all the treatmentsThemobile elementcontents significantly increased after digestate applicationfor most of the determined nutrients except Ca and Cu inChernozem (because of its low availability in the ameliorativematerials) More apparent increase of mobile element con-tents after application of digestate was observed for Luvisolcompared to Chernozem due to higher sorption capacityof Chernozem in accordance with their higher CEC levelFor example Table 4 shows 5-fold increase of mobile Mg


Table 3 The concentrations of Ca extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) the averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)

Chernozem Day 1 Day 2 Day 3 Day 4 Day 7 Day 14 Day 21Control 7555 plusmn 331a 7655 plusmn 183a 8390 plusmn a213a 9674 plusmn 219a 9034 plusmn 238ab 9856 plusmn 1191ab 6040 plusmn 270a

Control + Hg 8074 plusmn 260a 7694 plusmn 359a 7467 plusmn a677a 9607 plusmn 193a 8891 plusmn 702a 8951 plusmn 236ab 7865 plusmn 983abc

Digestate 8282 plusmn 735a 8094 plusmn 155a 8049 plusmn a687a 10122 plusmn 206a 8886 plusmn 362a 11004 plusmn 926b 12402 plusmn 2330bc

Digestate + Hg 8108 plusmn 232a 9656 plusmn 282a 7824 plusmn a454a 11360 plusmn 1521a 10104 plusmn 205b 10232 plusmn 499ab 11286 plusmn 1243c

Ash 8448 plusmn 548a 8246 plusmn a282a 8746 plusmn a272a 9898 plusmn 213a 9661 plusmn 466ab 9633 plusmn 203ab 9835 plusmn 2134abc

Ash + Hg 8164 plusmn 921a 8072 plusmn a511a 8717 plusmn a611a 10910 plusmn 898a 9862 plusmn 300ab 10599 plusmn 387ab 9359 plusmn 1118abc

(NH4)2SO4 7330 plusmn 57a 7409 plusmn a201a 8037 plusmn a311a 10134 plusmn 1290a 8942 plusmn 307a 8893 plusmn 990a 10045 plusmn 2115abc

(NH4)2SO4 + Hg 8041 plusmn 796a 7393 plusmn a359a 8350 plusmn 1151a 9820 plusmn 207a 8991 plusmn 382ab 10238 plusmn 790ab 7031 plusmn 3008abc

Luvisol Day 1 Day 2 Day 3 Day 4 Day 7 Day 14 Day 21Control 1404 plusmn 96a 1401 plusmn 73a 1372 plusmn 56a 1691 plusmn 51ab 1671 plusmn 90a 1764 plusmn 223a 1273 plusmn 125a

Control + Hg 1450 plusmn 93a 1407 plusmn 38a 1396 plusmn 45a 1635 plusmn 52a 1575 plusmn 107a 1655 plusmn 89a 1274 plusmn 283a

Digestate 3558 plusmn 121b 2593 plusmn 574b 2733 plusmn 492b 4086 plusmn 116d 3776 plusmn 264c 3294 plusmn 380b 3757 plusmn 428ab

Digestate + Hg 3455 plusmn 569b 3190 plusmn 282b 3139 plusmn 328b 3804 plusmn 613d 4462 plusmn 644c 3975 plusmn 206c 4758 plusmn 327b

Ash 2335 plusmn 433a 2382 plusmn 197a 2281 plusmn 321a 2540 plusmn 234bc 2917 plusmn 164b 2686 plusmn 281b 2121 plusmn 286ab

Ash + Hg 1981 plusmn 254a 1908 plusmn 149a 2044 plusmn 161a 2574 plusmn 512c 2717 plusmn 117b 3092 plusmn 190b 2784 plusmn 467ab

(NH4)2SO4 1514 plusmn 57a 1356 plusmn 36a 1411 plusmn 102a 1651 plusmn 69a 1597 plusmn 79a 1684 plusmn 135a 1663 plusmn 92ab

(NH4)2SO4 + Hg 1655 plusmn 54a 1577 plusmn 246a 1431 plusmn 59a 1742 plusmn 108abc 1616 plusmn 32a 1666 plusmn 124a 1690 plusmn 107ab

Table 4The concentrations of Mg extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) the averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)

Chernozem Day 1 Day 2 Day 3 Day 4 Day 7 Day 14 Day 21Control 389 plusmn 20a 401 plusmn 2ab 483 plusmn 8a 562 plusmn 18a 503 plusmn 48a 546 plusmn 23a 371 plusmn 50a

Control + Hg 347 plusmn 111a 406 plusmn 20abc 442 plusmn 32a 556 plusmn 16a 502 plusmn 69a 505 plusmn 34a 533 plusmn 135ab

Digestate 544 plusmn 50c 544 plusmn 30d 603 plusmn 65b 753 plusmn 52bc 656 plusmn 76ab 781 plusmn 54c 963 plusmn 155c

Digestate + Hg 519 plusmn 37c 603 plusmn 24e 610 plusmn 45b 809 plusmn 44d 734 plusmn 73b 742 plusmn 22bc 859 plusmn 77bc

Ash 442 plusmn 24ab 458 plusmn 27c 522 plusmn 22ab 612 plusmn 22ac 566 plusmn 56a 574 plusmn 66a 636 plusmn 147abc

Ash + Hg 432 plusmn 57ab 447 plusmn 9bc 518 plusmn 35ab 681 plusmn 72ab 555 plusmn 31a 626 plusmn 62ab 585 plusmn 122ab

(NH4)2SO4 374 plusmn 3a 394 plusmn 16ab 461 plusmn 13a 572 plusmn 72a 506 plusmn 59a 494 plusmn 71a 626 plusmn 171abc

(NH4)2SO4 + Hg 406 plusmn 30ab 390 plusmn 10a 468 plusmn 32a 566 plusmn 10a 505 plusmn 45a 553 plusmn 39a 489 plusmn 119a

Luvisol Day 1 Day 2 Day 3 Day 4 Day 7 Day 14 Day 21Control 65 plusmn 5a 72 plusmn 5a 71 plusmn 2a 89 plusmn 3a 120 plusmn 47a 129 plusmn 61a 89 plusmn 19a


Digestate 362 plusmn 27c 259 plusmn 70c 325 plusmn 52b 446 plusmn 5c 408 plusmn 40b 391 plusmn 51b 423 plusmn 11c

Digestate + Hg 364 plusmn 89c 336 plusmn 38c 363 plusmn 92b 460 plusmn 54c 476 plusmn 28b 416 plusmn 33b 366 plusmn 90c

Ash 144 plusmn 32b 156 plusmn 19b 162 plusmn 34ab 176 plusmn 21b 231 plusmn 51a 214 plusmn 66a 174 plusmn 40ab

Ash + Hg 116 plusmn 19b 121 plusmn 14ab 140 plusmn 21ab 178 plusmn 47b 214 plusmn 52a 243 plusmn 31a 240 plusmn 33b

(NH4)2SO4 73 plusmn 0a 68 plusmn 0a 72 plusmn 5a 85 plusmn 1a 120 plusmn 49a 114 plusmn 43a 120 plusmn 33a

(NH4)2SO4 + Hg 85 plusmn 9a 74 plusmn 5ab 76 plusmn 2ab 92 plusmn 7a 115 plusmn 46a 119 plusmn 50a 117 plusmn 38a

contents in the digestate treated Luvisol compared to up to40 increase of mobile Mg in Chernozem

Moller and Muller [34] reviewed recent research aboutnutrient availability after the field application of digestate andstated that there is no available information concerning theavailability of S although digestate seems to be a good sourceof S in soil this was also observed in our case (Table 2) wherethe S content in the digestate sample reached up to 06Similarly they stated that there were many published studiesdescribing the effect of anaerobic digestion on micronutri-ent distribution and bioavailability in sewage sludge but

rarely any concerning digestates Moreover the availability ofmicronutrients in the digestate can be affected by the widecomplex of various factors such as precipitation as sulfidecarbonate phosphates and hydroxides sorption to the solidfraction either biomass or inert suspended matter and theformation of complexes in solution with intermediates andcompounds produced during anaerobic digestion [34] Theapplication of digestate results in an improvement of cropyields compared to inorganic fertilizer Moreover analysis ofsoil solution showed that there was less potential for the lossof nutrients via leaching [35] in the digestate treated soil


Table 5 The concentrations of K extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) the averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)

Chernozem Day 1 Day 2 Day 3 Day 4 Day 7 Day 14 Day 21Control 68 plusmn 5a 78 plusmn 4a 78 plusmn 2a 84 plusmn 2a 92 plusmn 4a 95 plusmn 0a 53 plusmn 3a


Digestate 2882 plusmn 906b 2931 plusmn 491b 3026 plusmn 304b 3547 plusmn 163b 3615 plusmn 177c 3842 plusmn 277c 4408 plusmn 506b

Digestate + Hg 2461 plusmn 510b 3163 plusmn 128b 2961 plusmn 261b 3915 plusmn 370b 3780 plusmn 164d 3697 plusmn 191c 4283 plusmn 367b

Ash 269 plusmn 66a 284 plusmn 40a 294 plusmn 59a 317 plusmn 78a 374 plusmn 35cd 362 plusmn 18ab 406 plusmn 146a

Ash + Hg 260 plusmn 61a 305 plusmn 77a 310 plusmn 47a 467 plusmn 101a 362 plusmn 25bc 446 plusmn 63b 359 plusmn 82a

(NH4)2SO4 97 plusmn 5a 119 plusmn 11a 107 plusmn 6a 130 plusmn 13a 126 plusmn 6ab 117 plusmn 13ab 109 plusmn 6a

(NH4)2SO4 + Hg 105 plusmn 6a 109 plusmn 4a 112 plusmn 6a 135 plusmn 2a 130 plusmn 5abc 145 plusmn 10ab 1568 plusmn 207a



Digestate 3324 plusmn 201b 2684 plusmn 425b 3173 plusmn 54b 3857 plusmn 252b 3936 plusmn 37c 3665 plusmn 83c 4063 plusmn 418c

Digestate + Hg 3728 plusmn 541b 3306 plusmn 214b 3351 plusmn 540b 4065 plusmn 150b 3927 plusmn 308c 3655 plusmn 64c 3304 plusmn 180b

Ash 431 plusmn 146a 487 plusmn 78a 431 plusmn 111a 419 plusmn 70a 548 plusmn 66b 446 plusmn 71b 387 plusmn 18a

Ash + Hg 316 plusmn 70a 343 plusmn 41a 370 plusmn 39a 454 plusmn 102a 489 plusmn 15b 546 plusmn 66b 553 plusmn 118a


(NH4)2SO4 + Hg 159 plusmn 6a 158 plusmn 9a 152 plusmn 4a 176 plusmn 9a 169 plusmn 4a 162 plusmn 4a 170 plusmn 14a

Table 6The concentrations of Cu extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) the averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)

Chernozem Day 1 Day 2 Day 3 Day 4 Day 7 Day 14 Day 21Control 0045 plusmn 0007a 0039 plusmn 0008a 0015 plusmn 0003a 0025 plusmn 0003a 0162 plusmn 0018abc 0064 plusmn 0013a 0017 plusmn 0008a


Digestate 0224 plusmn 0092b 0230 plusmn 0098b 0187 plusmn 0037c 0299 plusmn 0010c 0362 plusmn 0051c 0517 plusmn 0089c 0911 plusmn 0141b

Digestate + Hg 0120 plusmn 0010a 0094 plusmn 0026a 0089 plusmn 0028b 0166 plusmn 0038b 0264 plusmn 0031bc 0334 plusmn 0031b 0763 plusmn 0065b

Ash 0053 plusmn 0019a 0059 plusmn 0014a 0032 plusmn 0007a 0054 plusmn 0012a 0065 plusmn 0042ab 0073 plusmn 0043a 0148 plusmn 0029a

Ash + Hg 0079 plusmn 0011a 0042 plusmn 0003a 0026 plusmn 0005a 0060 plusmn 0013a 0055 plusmn 0035a 0095 plusmn 0027a 0141 plusmn 0069a

(NH4)2SO4 0047 plusmn 0035a 0048 plusmn 0013a 0018 plusmn 0006a 0022 plusmn 0006a 0081 plusmn 0031ab 0091 plusmn 0038a 0090 plusmn 0060a

(NH4)2SO4 + Hg 0038 plusmn 0020a 0029 plusmn 0007a 0008 plusmn 0008a 0029 plusmn 0002a 0029 plusmn 0013a 0066 plusmn 0048a 0379 plusmn 0093ab


Control + Hg 0128 plusmn 0020a 0118 plusmn 0021ab 0098 plusmn 0011a 0156 plusmn 0024ab 0164 plusmn 0062a 0357 plusmn 0021ab 0230 plusmn 0062a

Digestate 0284 plusmn 0085a 0268 plusmn 0022b 0316 plusmn 0051b 0553 plusmn 0087c 0534 plusmn 0136b 0785 plusmn 0032d 1200 plusmn 0142c

Digestate + Hg 0166 plusmn 0122a 0095 plusmn 0012a 0120 plusmn 0055a 0131 plusmn 0092a 0119 plusmn 0015a 0594 plusmn 0137cd 0678 plusmn 0164ab

Ash 0196 plusmn 0026a 0161 plusmn 0036ab 0145 plusmn 0023ab 0269 plusmn 0051ab 0220 plusmn 0045a 0542 plusmn 0046bc 0493 plusmn 0081ab

Ash + Hg 0225 plusmn 0048ab 0261 plusmn 0024b 0193 plusmn 0016ab 0298 plusmn 0045b 0266 plusmn 0040a 0578 plusmn 0058c 0900 plusmn 0042bc

(NH4)2SO4 0101 plusmn 0022a 0191 plusmn 0048ab 0078 plusmn 0004a 0184 plusmn 0018ab 0161 plusmn 0024a 0308 plusmn 0051a 0658 plusmn 0103ab

(NH4)2SO4 + Hg 0140 plusmn 0027a 0138 plusmn 0028ab 0121 plusmn 0014a 0247 plusmn 0068ab 0193 plusmn 0050a 0422 plusmn 0101abc 0555 plusmn 0062ab

Also Froslashseth et al [36] observed that the field applicationof digestate contributed to higher soil aggregate stabilityAccording to Fernandez-Delgado Juarez et al [37] amendingsoils with digestate resulted in a higher nutrient content aswell as more efficient soil microbial community relative tothe variants treated with farmyard manure Therefore theapplication of digestate seemed to be the effectivemeasure forimmobilization of Hg in soil together with increase of mobilenutrients in these soils

The application of wood fly ash as a potential sourceof available nutrients in the soil is widely discussed in the

literature [38 39] The benefits on the growth of the plantsas the result of an increase in available P Ca Mg K andB and a decrease in Al toxicity was described [38] Steenariet al [40] tested the release of macro- and microelementsfrom various ash samples whereas low leaching rates wereobserved for the important plant nutrients P and Mg aswell as for Fe Mn Cu and Zn up to 50 of total K wasreleased during the batch leaching test In our case theextractable element contents in the ash amended samplesdiffered according to the experimental soil where Ca Feand Cu levels remained unchanged compared to the control


Table 7 The concentrations of Fe extractable with 011mol Lminus1 acetic acidwithin the incubation experiment (mgsdotkgminus1) The averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)



Digestate 493 plusmn 94c 954 plusmn 172c 1059 plusmn 26b 1425 plusmn 117c 1024 plusmn 27c 324 plusmn 53b 487 plusmn 64b

Digestate + Hg 270 plusmn 42b 619 plusmn 152b 771 plusmn 288b 731 plusmn 107b 694 plusmn 55b 480 plusmn 142c 483 plusmn 96b

Ash 131 plusmn 016a 2878 plusmn 586a 687 plusmn 197a 026 plusmn 010a 035 plusmn 011a 153 plusmn 017a 090 plusmn 024a






Digestate 1008 plusmn 331b 519 plusmn 254b 676 plusmn 406ab 447 plusmn 143b 774 plusmn 145b 425 plusmn 130a 1735 plusmn 710b

Digestate + Hg 1080 plusmn 387b 3409 plusmn 823b 3294 plusmn 704b 4137 plusmn 528c 4847 plusmn 972c 3969 plusmn 541b 3154 plusmn 638c





Table 8The concentrations of Mn extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) the averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)


Control + Hg 214 plusmn 44a 221 plusmn 34ab 207 plusmn 39a 362 plusmn 48a 366 plusmn 03a 373 plusmn 50c 378 plusmn 116a

Digestate 168 plusmn 22c 168 plusmn 12c 177 plusmn 10c 232 plusmn 4d 204 plusmn 4c 218 plusmn 11a 301 plusmn 68d

Digestate + Hg 152 plusmn 4c 181 plusmn 6c 168 plusmn 4c 229 plusmn 23d 204 plusmn 5c 208 plusmn 3c 266 plusmn 30cd

Ash 424 plusmn 73b 387 plusmn 98ab 575 plusmn 217b 702 plusmn 85bc 663 plusmn 106b 669 plusmn 140a 1015 plusmn 537ab

Ash + Hg 385 plusmn 92b 400 plusmn 44b 461 plusmn 70ab 968 plusmn 180c 739 plusmn 65b 931 plusmn 155ab 830 plusmn 323ab

(NH4)2SO4 238 plusmn 15a 241 plusmn 16ab 270 plusmn 07a 467 plusmn 50ab 697 plusmn 166b 1431 plusmn 197b 1256 plusmn 361bc

(NH4)2SO4 + Hg 264 plusmn 85a 280 plusmn 74ab 303 plusmn 93ab 392 plusmn 55ab 407 plusmn 98a 565 plusmn 139a 708 plusmn 336ab


Control + Hg 436 plusmn 08abc 433 plusmn 101ab 451 plusmn 70abc 674 plusmn 51ab 615 plusmn 67a 774 plusmn 85ab 378 plusmn 71a

Digestate 161 plusmn 9d 142 plusmn 23d 169 plusmn 8d 191 plusmn 2c 198 plusmn 25c 189 plusmn 19c 301 plusmn 30c

Digestate + Hg 148 plusmn 9d 176 plusmn 2e 180 plusmn 5d 222 plusmn 10d 223 plusmn 11c 229 plusmn 11d 266 plusmn 81c

Ash 549 plusmn 104c 594 plusmn 88b 532 plusmn 90bc 870 plusmn 142b 1314 plusmn 423b 1140 plusmn 238b 1015 plusmn 341b

Ash + Hg 544 plusmn 72c 586 plusmn 24b 589 plusmn 48c 860 plusmn 121b 819 plusmn 58ab 1089 plusmn 08b 830 plusmn 691a

(NH4)2SO4 279 plusmn 05ab 285 plusmn 15a 290 plusmn 17a 503 plusmn 83a 428 plusmn 66a 609 plusmn 124a 1256 plusmn 32b

(NH4)2SO4 + Hg 465 plusmn 46bc 469 plusmn 52ab 426 plusmn 32ab 624 plusmn 124ab 659 plusmn 60a 636 plusmn 29a 708 plusmn 52a

On the contrary the extremely high Zn level in the ash(Table 2) resulted in the significant increase in the extractableZn portion of the ash-treated soil regardless of the soil type(Table 11) A similar pattern was reported for Mg where theincrease in the extractable Mg portion was more apparentin Luvisol (Table 4) Whereas in the Luvisol the mobile Mgcontents increased twice after ash application the mobileportion of Mg in Chernozem rised only by 10ndash15 The lowmobility of micronutrients in various ash samples was alsoconfirmed by Szakova et al [41]TheKMn and P extractablelevels tended to increase compared to controls (significance of

the differences at 119875 lt 005 was unambiguously proved onlyin the case of Mn see Table 8) but were significantly lowercompared to digestate application not confirming the highK leachability from ash samples observed by Steenari et al[40] Although the total S contents added via the individualtreatments were comparable the mobile portions of ash-derived S were lower compared to those after the applicationof digestate and ammonium sulfate Ochecova et al [20]observed increasing mobile portions of Ca P K Mg andMnin the fly ash-treated soil after a 3-yearmodel pot experimentHowever the effects were significant for the 3ndash6 fold higher


Table 9 The concentrations of P extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) the averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)



Digestate 2590 plusmn 500b 2690 plusmn 495b 2352 plusmn 632b 3209 plusmn 605b 1891 plusmn 235b 2786 plusmn 305b 2460 plusmn 599b

Digestate + Hg 2509 plusmn 624b 2856 plusmn 283b 2616 plusmn 404b 3610 plusmn 142b 2936 plusmn 125c 2745 plusmn 517b 2535 plusmn 518b





Luvisol Day 1 Day 2 Day 3 Day 4 Day 7 Day 14 Day 21Control 629 plusmn 58a 619 plusmn 63a 612 plusmn 111a 708 plusmn 06a 658 plusmn 163a 56627 plusmna 389 plusmn 38a


Digestate 3237 plusmn 262b 2102 plusmn 676b 2034 plusmn 587b 3234 plusmn 143b 2903 plusmn 301b 2458 plusmn 568b 2540 plusmn 240c

Digestate + Hg 3296 plusmn 829b 2865 plusmn 406b 2463 plusmn 772b 3500 plusmn 448b 3486 plusmn 904b 2622 plusmn 287b 1307 plusmn 489b



(NH4)2SO4 613 plusmn 11a 583 plusmn 36a 573 plusmn 40a 691 plusmn 82a 594 plusmn 48a 593 plusmn 42a 606 plusmn 92 a


Table 10 The concentrations of S extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) the averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)



Digestate 2550 plusmn 1141bc 1995 plusmn 548b 1290 plusmn 317b 897 plusmn 213ab 661 plusmn 35ab 1322 plusmn 529ab 2113 plusmn 939bc

Digestate + Hg 1414 plusmn 304b 2216 plusmn 296b 1627 plusmn 462b 1981 plusmn 636ab 916 plusmn 67ab 1364 plusmn 491ab 3076 plusmn 1108cd

Ash 1381 plusmn 376b 1408 plusmn 329b 1439 plusmn 330b 1538 plusmn 373ab 1681 plusmn 120b 1654 plusmn 161ab 2019 plusmn 627bc

Ash + Hg 1382 plusmn 202b 1589 plusmn 75b 1552 plusmn 219b 2436 plusmn 418ab 1926 plusmn 33b 2050 plusmn 287b 2025 plusmn 547bc

(NH4)2SO4 3440 plusmn 820c 4943 plusmn 1536c 4545 plusmn 796c 6026 plusmn 1455c 4836 plusmn 552c 5284 plusmn 917c 5196 plusmn 1046e

(NH4)2SO4 + Hg 3663 plusmn 667c 4458 plusmn 946c 3867 plusmn 131c 6606 plusmn 1893c 4832 plusmn 1623c 7665 plusmn 787d 4297 plusmn 1236de



Digestate 2964 plusmn 274bc 2216 plusmn 275bc 2755 plusmn 322bc 4205 plusmn 1224cd 3291 plusmn 620cd 2203 plusmn 1211b 2649 plusmn 1014b

Digestate + Hg 2732 plusmn 556bc 2059 plusmn 197bc 2342 plusmn 462bc 2297 plusmn 489bc 803 plusmn 266ab 949 plusmn 111ab 3625 plusmn 932b

Ash 1832 plusmn 752b 1832 plusmn 200b 2145 plusmn 640b 2082 plusmn 156b 2236 plusmn 138bc 1983 plusmn 140b 1510 plusmn 271b

Ash + Hg 1345 plusmn 216b 1316 plusmn 118b 1528 plusmn 212b 2191 plusmn 272bc 2334 plusmn 345bc 2287 plusmn 406b 2034 plusmn 368b

(NH4)2SO4 4435 plusmn 963c 4030 plusmn 960c 4666 plusmn 878c 5904 plusmn 1309d 4303 plusmn 975d 5052 plusmn 1086c 5708 plusmn 1185c

(NH4)2SO4 + Hg 5361 plusmn 616c 5641 plusmn 302c 5410 plusmn 780c 6878 plusmn 879e 5601 plusmn 248e 5644 plusmn 726c 7018 plusmn 318c

ash rate compared to our experiment Thus the increase ofmobile nutrient contents in soils will manifest at higher ashrates compared to our experiment

The interrelationships between soil Hg and other soilelement contents described by Reis et al [14] indicate that thepresence ofHg in themobile phase could be related toMnandAl soil contents Furthermore an antagonistic effect of MnagainstHg is suggestedOur data tended to increase ofmobileMn contents during the incubation (Table 8) as relatedto decreasing mobile Hg (Figure 1) Similarly Sierra et al

[42] observed negative significant correlation between theavailable Mn in the rhizosphere and Hg content in plantsOn the contrary S content contributed to Hg retention inthe soil matrix reducing the mobility of the metal [14] Inour case the changes of Hg mobility in soils (Figure 1) didnot reflect the changes in mobile portion of S during theincubation experiment (Table 10) In contrast the presenceof sulfates seems to favor Hg uptake by the plant Therewas a positive significant correlation between the sulfateconcentration in the rhizosphere and the Hg within the


Table 11The concentrations of Zn extractable with 011mol Lminus1 acetic acid within the incubation experiment (mgsdotkgminus1) the averages markedby the same letter did not significantly differ at 119875 lt 005 within individual columns data are presented as mean plusmn standard deviation (119899 = 3)



Digestate 656 plusmn 081a 669 plusmn 121a 602 plusmn 111a 902 plusmn 093a 744 plusmn 026a 1106 plusmn 122a 1251 plusmn 137a

Digestate + Hg 523 plusmn 136a 574 plusmn 082a 521 plusmn 084a 776 plusmn 034a 669 plusmn 026a 789 plusmn 017a 998 plusmn 151a

Ash 1093 plusmn 232b 521 plusmn 200b 858 plusmn 218b 939 plusmn 237b 1029 plusmn 122b 772 plusmn 173b 1266 plusmn 329b

Ash + Hg 526 plusmn 258b 471 plusmn 104b 815 plusmn 214b 1538 plusmn 257c 1085 plusmn 316b 1376 plusmn 224c 1543 plusmn 288b







Ash 1816 plusmn 307b 1729 plusmn 288b 1614 plusmn 328b 1646 plusmn 310b 2142 plusmn 245c 1556 plusmn 258b 1158 plusmn 230b

Ash + Hg 1124 plusmn 318b 922 plusmn 123b 1211 plusmn 233b 1658 plusmn 346b 1626 plusmn 46b 2019 plusmn 357b 2309 plusmn 387c



aerial and root parts of plants [42] However only totalS extracted with the 011mol Lminus1 solution of CH

3

COOHwas determined by the ICP-OES and a portion of mobilesulfates in the extract was not determined in our caseand requires further research The competition between Hgand Cu and Hg and Zn in soils described by Jing et al[19] was not confirmed in our case For Fe Mehrotra andSedlak [43] and Rhoton and Bennett [44] highlighted Hgimmobilization via sorption andor the complexation of Hgwith Fe compounds in soil This statement seems to beconfirmed for Chernozem whereas the opposite pattern wasobserved in Luvisol In Chernozem the mobile portions ofFe decreased significantly after digestate application on theHg amended samples compared to the unamended onesIn Luvisol the mobile Fe contents increased in the Hg +digestate amended samples since 2nd day of incubation withmaximum at 7th day suggesting competitive relationships ofFe and Hg in this case The complexity of Hg sorption onFeMn oxides was documented by Liang et al [45] wherethe role of amorphouscrystalline Fe and Mn hydroxideshumic acids content and also chlorine concentrations werementioned Sıpkova et al [46] observed a negative correlationbetweenHg content bound to the humic acids and the contentof Mg Mn and Fe Therefore the more detailed informationconcerning soil components humic acid portions in thedigestate as well as the importance of the application ofHgCl2

compared to the other Hg compounds remains to beelucidated in further research

4 Conclusions

Although the response of Hg contaminated soils in differentameliorative materials was affected by the individual param-eters of the soils especially by the different soil sorption

capacity and organic matter contents in these soils digestateproved to be the most effective for the immobilization ofHg in soil Contrary to the other S-bearing measures suchas wood fly ash and ammonium sulfate in the case ofdigestate the Hg immobilizing effectiveness resulted fromthe cooperation of various factors such as S and organicmatter content Moreover the digestate application can resultin an improvement in the macro- and micronutrient statusof the soil where mobile and theoretically plant-availableportions of these elements increased in particular Thusthe field application of organic matter-rich biowaste such asdigestate seems to be reasonable for the disposal of this typeof material leading to a decreased environmental risk of Hgcontamination in soil

Conflict of Interests

The authors declared that there is no conflict of interests

Acknowledgments

Authors are thankful for financial support of the GACRProject P503120682 ESF and MSMT Project no CZ1072300300040 and Czech University of Life Science Projectno 2114013133130 correction and improvement of languagewas provided by Proof-Reading-Servicecom Ltd Devon-shire Business Centre Works Road Letchworth Garden CitySG6 1GJ United Kingdom

References

[1] EPAMercury Study Report to Congress vol 1 of Executive Sum-mary EPA-452R-97-003 GPO Washington DC USA 1997


[2] E Tipping S Lofts H Hooper B Frey D Spurgeon and CSvendsen ldquoCritical Limits for Hg(II) in soils derived fromchronic toxicity datardquo Environmental Pollution vol 158 no 7pp 2465ndash2471 2010

[3] J Li Y Lu H Shim et al ldquoUse of the BCR sequential extractionprocedure for the study of metal availability to plantsrdquo Journalof Environmental Monitoring vol 12 no 2 pp 466ndash471 2010

[4] S M Rodrigues B Henriques J Coimbra E F da Silva M EPereira and A C Duarte ldquoWater-soluble fraction of mercuryarsenic and other potentially toxic elements in highly contam-inated sediments and soilsrdquo Chemosphere vol 78 no 11 pp1301ndash1312 2010

[5] L Boszke A Kowalski A Astel A Baranski B Gworek andJ Siepak ldquoMercury mobility and bioavailability in soil fromcontaminated areardquo Environmental Geology vol 55 no 5 pp1075ndash1087 2008

[6] W Luo Y Lu B Wang et al ldquoDistribution and sources of mer-cury in soils from former industrialized urban areas of BeijingChinardquo Environmental Monitoring and Assessment vol 158 no1ndash4 pp 507ndash517 2009

[7] A Hassen N Saidi M Cherif and A Boudabous ldquoResistanceof environmental bacteria to heavy metalsrdquo Bioresource Tech-nology vol 64 no 1 pp 7ndash15 1998

[8] A R Khwaja P R Bloom and P L Brezonik ldquoBinding con-stants of divalent mercury (Hg2+) in soil humic acids and soilorganic matterrdquo Environmental Science amp Technology vol 40no 3 pp 844ndash849 2006

[9] D A Heeraman V P Claassen and R J Zasoski ldquoInteractionof lime organic matter and fertilizer on growth and uptake ofarsenic and mercury by Zorro fescue (Vulpia myuros L)rdquo Plantand Soil vol 234 no 2 pp 215ndash231 2001

[10] M Linde I Oborn and J P Gustafsson ldquoEffects of changedsoil conditions on the mobility of trace metals in moderatelycontaminated urban soilsrdquo Water Air and Soil Pollution vol183 no 1ndash4 pp 69ndash83 2007

[11] A Yao R Qiu C Qing S Mu and E J Reardon ldquoEffects ofhumus on the environmental activity of mineral-bound Hginfluence on Hg plant uptakerdquo Journal of Soils and Sedimentsvol 11 no 6 pp 959ndash967 2011

[12] Y Yang L Liang andDWang ldquoEffect of dissolved organicmat-ter on adsorption and desorption of mercury by soilsrdquo Journalof Environmental Sciences vol 20 no 9 pp 1097ndash1102 2008

[13] G J Zagury C-M Neculita C Bastien and L DeschenesldquoMercury fractionation bioavailability and ecotoxicity inhighly contaminated soils from chlor-alkali plantsrdquo Environ-mental Toxicology and Chemistry vol 25 no 4 pp 1138ndash11472006

[14] A T Reis S M Rodrigues C M Davidson E Pereira and AC Duarte ldquoExtractability and mobility of mercury from agri-cultural soils surrounding industrial and mining contaminatedareasrdquo Chemosphere vol 81 no 11 pp 1369ndash1377 2010

[15] M O Barnett L A Harris R R Turner et al ldquoFormation ofmercuric sulfide in soilrdquo Environmental Science amp Technologyvol 31 no 11 pp 3037ndash3043 1997

[16] D Hesterberg J W Chou K J Hutchison and D E SayersldquoBonding of HG(II) to reduced organic sulfur in humic acid asaffected by SHg ratiordquo Environmental Science and Technologyvol 35 no 13 pp 2741ndash2745 2001

[17] S Remy P Prudent and J-L Probst ldquoMercury speciation insoils of the industrialised Thur River catchment (AlsaceFrance)rdquo Applied Geochemistry vol 21 no 11 pp 1855ndash18672006

[18] S Akerblom K Bishop E Bjorn L Lambertsson T Erikssonand M B Nilsson ldquoSignificant interaction effects from sulfatedeposition and climate on sulfur concentrations constitutemajor controls on methylmercury production in peatlandsrdquoGeochimica et Cosmochimica Acta vol 102 pp 1ndash11 2013

[19] Y D Jing Z L He and X E Yang ldquoEffects of pH organic acidsand competitive cations onmercury desorption in soilsrdquoChem-osphere vol 69 no 10 pp 1662ndash1669 2007

[20] P Ochecova P Tlustos and J Szakova ldquoWheat and soilresponse to wood fly ash application in contaminated soilsrdquoAgronomy Journal vol 106 no 3 pp 995ndash1002 2014

[21] P Quevauviller A Ure H Muntau and B Griepink ldquoImprove-ment of analytical measurements within the BCR-programmdashsingle and sequential extraction procedures applied to soiland sediment analysisrdquo International Journal of EnvironmentalAnalytical Chemistry vol 51 pp 129ndash134 1993

[22] A Mehlich ldquoMehlich 3 soil test extractant a modification ofMehlich 2 extractantrdquo Communications in Soil Science amp PlantAnalysis vol 15 no 12 pp 1409ndash1416 1984

[23] A Sıpkova J Szakova P CoufalıkO Zverina L Kacalkova andP Tlustos ldquoMercury distribution and mobility in contaminatedsoils from vicinity of waste incineration plantrdquo Plant Soil andEnvironment vol 60 no 2 pp 87ndash92 2014

[24] P Ruggiero R Terzano M Spagnuolo et al ldquoHg bioavailabilityand impact on bacterial communities in a long-term pollutedsoilrdquo Journal of EnvironmentalMonitoring vol 13 no 1 pp 145ndash156 2011

[25] B Demirel N P Gol and T T Onay ldquoEvaluation of heavymetal content in digestate from batch anaerobic co-digestion ofsunflower hulls and poultry manurerdquo Journal of Material Cyclesand Waste Management vol 15 no 2 pp 242ndash246 2013

[26] R Poykio H Nurmesniemi and R L Keiski ldquoTotal and sizefractionated concentrations of metals in combustion ash fromforest residues and peatrdquo Proceedings of the Estonian Academyof Sciences vol 58 no 4 pp 247ndash254 2009

[27] J Bower K S Savage B Weinman M O Barnett W PHamilton and W F Harper ldquoImmobilization of mercury bypyrite (FeS

2

)rdquo Environmental Pollution vol 156 no 2 pp 504ndash514 2008

[28] A KMuller KWestergaard S Christensen and S J SoslashrensenldquoThe effect of long-termmercury pollution on the soilmicrobialcommunityrdquo FEMS Microbiology Ecology vol 36 no 1 pp 11ndash19 2001

[29] P Pant and C M Allen ldquoInteraction of soil and mercury as afunction of soil organic carbon some field evidencerdquo Bulletin ofEnvironmental Contamination and Toxicology vol 78 no 6 pp539ndash542 2007

[30] F A O Camargo F M Bento and R J S Jacques ldquoUso demicrorganismos para remediacao de metaisrdquo in Topicos emCiencia do Solo CACeretta L S Silva and JMReichert Edspp 468ndash496 Sociedade Brasileira de Ciencia do Solo MinasGerais Brazil 2007

[31] MRavichandran ldquoInteractions betweenmercury and dissolvedorganic mattermdasha reviewrdquo Chemosphere vol 55 no 3 pp 319ndash331 2004

[32] A Kabata-Pendias Trace Elements in Soils and Plants CRCPress LLC Boca Raton Fla USA 3rd edition 2001

[33] V B Mathema B C Thakuri and M Sillanpaa ldquoBacterial meroperon-mediated detoxification of mercurial compounds ashort reviewrdquo Archives of Microbiology vol 193 no 12 pp 837ndash844 2011


[34] K Moller and T Muller ldquoEffects of anaerobic digestion ondigestate nutrient availability and crop growth a reviewrdquoEngineering in Life Sciences vol 12 no 3 pp 242ndash257 2012

[35] J J Walsh D L Jones G Edwards-Jones and A P WilliamsldquoReplacing inorganic fertilizer with anaerobic digestate maymaintain agricultural productivity at less environmental costrdquoJournal of Plant Nutrition and Soil Science vol 175 no 6 pp840ndash845 2012

[36] R B Froslashseth A K Bakken M A Bleken et al ldquoEffects ofgreen manure herbage management and its digestate frombiogas production on barley yield N recovery soil structure andearthwormpopulationsrdquoEuropean Journal of Agronomy vol 52pp 90ndash102 2014

[37] M Fernandez-Delgado Juarez S Waldhuber A Knapp CPartl M Gomez-Brandon and H Insam ldquoWood ash effectson chemical and microbiological properties of digestate- andmanure-amended soilsrdquoBiology and Fertility of Soils vol 49 no5 pp 575ndash585 2013

[38] A Demeyer J C Voundi Nkana andM G Verloo ldquoCharacter-istics of wood ash and influence on soil properties and nutrientuptake an overviewrdquo Bioresource Technology vol 77 no 3 pp287ndash295 2001

[39] R M Pitman ldquoWood ash use in forestrymdasha review of the envi-ronmental impactsrdquo Forestry vol 79 no 5 pp 563ndash588 2006

[40] B-M Steenari L G Karlsson and O Lindqvist ldquoEvaluation ofthe leaching characteristics of wood ash and the influence of ashagglomerationrdquo Biomass and Bioenergy vol 16 no 2 pp 119ndash136 1999

[41] J Szakova P Ochecova T Hanzlıcek I Perna and P TlustosldquoVariability of total and mobile element contents in ash derivedfrom biomass combustionrdquo Chemical Papers vol 67 no 11 pp1376ndash1385 2013

[42] M J Sierra J Rodrıguez-Alonso and R Millan ldquoImpactof the lavender rhizosphere on the mercury uptake in fieldconditionsrdquo Chemosphere vol 89 no 11 pp 1457ndash1466 2012

[43] A S Mehrotra and D L Sedlak ldquoDecrease in net mercurymethylation rates following iron amendment to anoxic wetlandsediment slurriesrdquo Environmental Science and Technology vol39 no 8 pp 2564ndash2570 2005

[44] F E Rhoton and S J Bennett ldquoSoil and sediment propertiesaffecting the accumulation of mercury in a flood control reser-voirrdquo Catena vol 79 no 1 pp 39ndash48 2009

[45] P Liang Y-C Li C Zhang et al ldquoEffects of salinity and humicacid on the sorption of Hg on Fe and Mn hydroxidesrdquo Journalof Hazardous Materials vol 244-245 pp 322ndash328 2013

[46] A Sıpkova J Szakova and P Tlustos ldquoAffinity of selected ele-ments to individual fractions of soil organic matterrdquoWater Airamp Soil Pollution vol 225 no 1 article 1802 2014

Submit your manuscripts athttpwwwhindawicom

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ClimatologyJournal of


this context the effect of a particular humus fraction on Hgbioavailability is related to its ability to convert Hg bound bysolid phases into soluble complexes as well as the stabilityof the released complexes On the contrary the presenceof dissolved organic matter (DOM) can significantly reducemaximum Hg adsorption capacity and even promote Hgdesorption from the soils [12]

Zagury et al [13] evaluated the potential mobility andplant-availability of Hg in the highly contaminated soilsby chlor-alkali plants where the total Hg contents in soilreached up to 11500mgsdotkgminus1 Although the water extractableHg portion was relatively low with regard to the high totalcontent it represented significant concentrations correlatingwith Hg uptake by experimental plants

Reis et al [14] observed that the presence of Hg in themobile phase could be related to Mn and aluminum (Al) soilcontents A positive relation between Hg in the semimobilefraction and the Al content was also observed On the con-trary organic matter and S contents contributed to Hgretention in the soil matrix reducing the mobility of themetal Sulfide minerals are known to be effective adsorbentsfor Hg(II) being the primary sink for Hg in the environment[15] In this context Hesterberg et al [16] demonstrated thepreferential binding of Hg(II) to reduced organic S sites Sub-sequently similar observations were provided and describedin soils as mentioned by Remy et al [17] Concentration ofMeHg is negatively correlated with soil total organic matterand total S and is influenced by the soil totalHg concentration[17] Akerblom et al [18] highlighted that long-term chronicSO4

2minus deposition at rates similar to those found in pollutedareas of Europe and North America increase the capacityof peatlands to methylate Hg and store MeHg Competitiverelationships between Hg and other metals in soil wereobserved by Jing et al [19] where desorption of adsorbed Hgincreased with elevated concentrations of added Cu or Zn

In our investigation a laboratory batch incubation exper-iment was conducted with Chernozem and Luvisol differingin their physicochemical parameters and the available nutri-ent contents Digestate the bio-waste originating from biogasproduction plants was applied as a S-rich source of organicmatter Alternatively wood ash from biomass combustionplants was applied as a different source of S and other macro-and micronutrients As proven by Ochecova et al [20] theplant-availability of the risk elements in the contaminated soildecreased after ash application whereas the nutrient contentstended to increase To separate the effect of organic matterand S in the soil inorganic source of S ammonium sulfate(NH4

)2

SO4

was applied as well The main objectives of thestudy were as follows (i) to assess the ability of the individualtreatments to immobilize Hg in the artificially contaminatedsoil and (ii) to evaluate the potential interactions betweenHg sorption in the experimental soil and the mobility of theessential macro- and microelements in these soils

2 Materials and Methods

21 Soils and Ameliorative Materials The following twosoils differing in their physicochemical characteristics were

Table 1 Main physicochemical characteristics of the experimentalsoils

Soil type Luvisol ChernozemNRSC Soil Texture Silt loam Silt loamClay (lt0002mm) [] 538 218Silt (0002ndash005mm) [] 6814 7180Sand (005ndash2mm) [] 2648 2603

Location 50∘410158402210158401015840N14∘1010158401910158401015840E

50∘710158404010158401015840N14∘2210158403310158401015840E

Altitude (m asl) 410 286P Mehlich IIIlowast (mg kgminus1) 100 91K Mehlich IIIlowast (mg kgminus1) 80 230Mg Mehlich IIIlowast (mg kgminus1) 110 240Ca Mehlich IIIlowast (mg kgminus1) 3600 9000lowastSıpkova et al [23]

selected for the experiment (i) uncontaminated Chernozemwith a cation exchange capacity (CEC) of 230mmol kgminus1a pH level of 75 and an oxidizable carbon content (Cox)of 26 and (ii) uncontaminated Luvisol with a CEC of145mmol kgminus1 a pH level of 65 and a Cox of 17 Nutrientcontents and other characteristics in both soil samples aresummarized in Table 1 Soils were sampled from a depthof 20 cm immediately after which they were homogenizedsieved through a 5mm diameter mesh and kept at roomtemperature For the experimental incubation soils sampleswere sieved again using a 2mm mesh and kept at 4∘C untiluse The fly ash (pH 121) was produced by the combustion ofwood ash produced in two reactors (18MW and 06MW)The digestate sample (pH 82) originated from a biogasstation (1732 kWh) where the digested material consistedof sugar beet pulp (50) marc of fruit (42) and silagemaize (8) The macro- and micronutrient contents in bothameliorative materials are summarized in Table 2 As aninorganic amendment solid particles of (NH

4

)2

SO4

wereused (Reagent from Fisher Scientific)

22 Experimental Design For the experimental incubationsoils 100 g of Chernozem and Luvisol soils were placed intopolypropylene bottles and immediately after were brought to60 moisture saturation Then half of the soil samples wereartificially contaminated with Hg by adding 60mg of HgCl

2

to reach a concentration of 440mgsdotkgminus1 of Hg Subsequentlyorganic and inorganic amendments (1) ash (2) digestateand (3) (NH

4

)2

SO4

were applied both to contaminatedand noncontaminated soils The rate of amendment wascalculated for 600mg S per kg of soil as follows (1) ash 15 g(2) digestate 10 g and (3) NH

4

SO4

025 g per bottleSoils that were contaminated and noncontaminated with

Hg were thoroughly mixed and incubated at 28∘C for 21 daysTo evaluate the mobility of Hg in both soils and interactionswith macro- and micronutrients as well soil samples werecollected after 1 2 3 4 7 14 and 21 days of incubationThreereplicates were set up per treatment





3


3



NO3


3











0

20

40

60

80

100

1 6 11 16 21


Chernozem

ControlAsh

0

2

4

6

8

0

100

200

300

400

1 6 11 16 21


Luvisol

Digestate(NH4)2SO4


(NH4)2SO4

Exce

pt d

iges

tate

(mgmiddot

kgminus1)

Exce

pt d

iges

tate

(mgmiddot

kgminus1)

Dig

esta

te (m

gmiddotkg

minus1)

Dig

esta

te (m

gmiddotkg

minus1)

080

060

040

020

000

















































































































































































3



4 Conclusions





Acknowledgments


References





























2


























Journal of












Volume 2014

Advances in









Geophysics


















3


3



NO3


3











0

20

40

60

80

100

1 6 11 16 21


Chernozem

ControlAsh

0

2

4

6

8

0

100

200

300

400

1 6 11 16 21


Luvisol

Digestate(NH4)2SO4


(NH4)2SO4

Exce

pt d

iges

tate

(mgmiddot

kgminus1)

Exce

pt d

iges

tate

(mgmiddot

kgminus1)

Dig

esta

te (m

gmiddotkg

minus1)

Dig

esta

te (m

gmiddotkg

minus1)

080

060

040

020

000

















































































































































































3



4 Conclusions





Acknowledgments


References





























2


























Journal of












Volume 2014

Advances in









Geophysics















0

20

40

60

80

100

1 6 11 16 21


Chernozem

ControlAsh

0

2

4

6

8

0

100

200

300

400

1 6 11 16 21


Luvisol

Digestate(NH4)2SO4


(NH4)2SO4

Exce

pt d

iges

tate

(mgmiddot

kgminus1)

Exce

pt d

iges

tate

(mgmiddot

kgminus1)

Dig

esta

te (m

gmiddotkg

minus1)

Dig

esta

te (m

gmiddotkg

minus1)

080

060

040

020

000

















































































































































































3



4 Conclusions





Acknowledgments


References





























2


























Journal of












Volume 2014

Advances in









Geophysics
























































































































































































3



4 Conclusions





Acknowledgments


References





























2


























Journal of












Volume 2014

Advances in









Geophysics









































2


























Journal of












Volume 2014

Advances in









Geophysics
































Journal of












Volume 2014

Advances in









Geophysics














Applications of Organic and Inorganic Amendments Induce Changes in the Mobility of Mercury and...

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Transcript of Applications of Organic and Inorganic Amendments Induce Changes in the Mobility of Mercury and...