Institute of Technology Assessment of the Austrian Academy of Sciences No. 040en • August 2014

Introduction

Based on their special chemical and phys-ical properties, synthetically produced na -nomaterials (engineered nanomaterials,ENMs) are currently being used in a widerange of products and applications. TheNanomaterial Databank of “Nanowerk”1

currently lists nanomaterials composed of28 different elements as well as of carbon(fullerenes, CNT, graphene), quantum dotsconsisting of several semi-conductor ma-terials, a large number of simple nanopar-ticulate compounds (oxides, carbonates, ni-trides) and those made up of complex com-pounds containing several components. Onthe one hand, the application of nanoma-terials promises reduction potentials andsustainability effects for the environment,for example through resource and mate-rial savings (see2). On the other hand, weknow very little about the behavior of na -nomaterials or about environmental andhealth risks when these products enter var-ious waste streams at the end of their lifecycles. A better understanding of the risksin the so-called End-of-Life-Phase (EOL)calls for considering the different dispos-al pathways and potential transformationprocesses that nanomaterials undergo inwaste treatment plants. In the disposalphase no consideration is being given toeither the special properties of nanoma-terials or to potential recovery and re-use.3

There is no special legal framework in placefor a separate treatment of nanomaterial-containing wastes (see4) or the monitoringof the processes. A prerequisite for such aframework would be exact knowledgeabout the nanomaterials being used, theirform (species) and composition, potentialtransformation processes as well as aboutamounts and concentrations. Such infor-mation, however, is not available, and vir-tually no studies have been conducted onthe EOL phase of products containing na -nomaterials. Very little is known about hownanomaterial-containing wastes behave inthermal, biological or mechanical-biolog -ical waste treatment plants or in landfills.5

What is “nanowaste”?

Nanomaterials can potentially be releasedinto the environment along the entire prod -uct life cycle through mechanical and/orchemical effects. According to a proposalby Boldrin et al.6, nanomaterials that en-ter the environment from diffuse sourcescan be classified as potential “nanopollu-tants” (for example titanium dioxide nano -particles released from sunscreen lotionsin surface waters). Accordingly, the term“nanowaste” is first applicable when na -nomaterials come into contact with solidwastes and can be collected separately.

Summary

Based on their special chemical and phys -i cal properties, synthetically producednanomaterials are currently being usedin a wide range of products and appli-cations. At the end of their product lifecycle, nanomaterials can enter wastetreat ment plants and landfills via diversewaste streams. Little, however, is knownabout how nanomaterials behave in thedisposal phase and whether potential en -vironmental or health risks arise. Thereare no specific legal requirements for aseparate treatment of nanomaterial-con -taining wastes. Virtually no informationis available about the nanomaterials cur -rently in use, their form and composi-tion, or about their amounts and con-centrations. The current assumption isthat stable nanoparticles (e.g. metal ox-ides) are neither chemically nor physi-cally altered in waste incineration plantsand that they accumulate especially inthe residues (e.g. slag). These residuesare ultimately dumped. The disposalprob lem in the case of stable nanopar-ticles is therefore merely shifted to thesubsequent steps in the waste treatmentprocess. Carbon nanotubes (CNT) arealmost completely combusted in incin-eration plants. Filter systems seem to beonly partially efficient, and a release ofnanoparticles into the environment can-not be excluded. Incinerating nanoma-terials contained in products can alsopromote the development of organic pol -lutants as undesired by-products. Onlyfew studies are available on the behav-ior of nanomaterials in landfills. More-over, recycling such products could re-lease nanomaterials, most likely whenthese are shredded and crushed.

1

“Nanowaste”Nanomaterial-containing products at the end of their life cycle

Sabine Greßler, Florian Part,André Gazsó*

* Corresponding authorFigure 1: Differentiation between “nanopollutant” and “nanowaste”, i.e. solid waste that contains nanomaterials7

No. 040en • August 2014

Titanium dioxide nanoparticles therefore be -come waste only when they are for exam-ple eliminated in wastewater treatment plantsafter the biological purification phase. Na -nomaterial-containing sludge which requiresfurther treatment according to the AustrianWaste Management Act (Abfallwirtschafts-gesetz; AWG) is termed “nanowaste”. Nano-material-containing wastes from productionprocesses and households (e.g. productionrejects or „nanoproducts”) are also classi-fied as “nanowaste” (Fig. 1).

Practical considerations dictate distinguish-ing between “nanowaste” and “nanopollu-tant” because quantifying ENMs in wastestreams is a precondition for determining po-tential limit values. A distinction is also nec-essary in order to be able to differentiate thedefinition of “waste” in the waste legislationframework from other environmental laws.Accordingly, wastes are first subject to theWaste Management Act when there is, resp.was, an intention to discard or when theircollection, storage, transportation and treat-ment is necessary in the public interest.

European and Austrian waste legislation cur-rently contain no nano-specific regulations8.Additional studies – in particular regardingthe persistence of and changes undergoneby nanomaterials in waste – will be requiredto be able to draw conclusions about wheth -er nano-specific limit values might becomenecessary in the future.

Nanomaterials in waste streams

Austria generates more than 50 million tonsof waste per year. Materials that arise fromdigging or excavating the soil or subsoil makeup the largest proportion (Fig. 2). Such ex-cavated material could be contaminated withnanomaterials via several pathways, for ex-ample through nanomaterial-containingbuilding materials. No studies are availableon this issue. Ash and slag from thermalwaste treatment plants can also contain na -nomaterials, as can construction wastes (seefurther below) or household wastes. In prin-ciple, nanomaterials can be present in allwaste categories.

“Nanowaste” can already arise in ENM pro-duction and use by industry and trade, forexample in the form of faulty batches, pro-duction wastes, filter residues, of wiping clothsor solvents contaminated with nanoparticles,but also as residues produced by researchand development facilities.

According to a working group commissionedby the Swiss Bundesamt für Umwelt (BAFU;Federal Department of the Environment),companies that produce or process synthet-ic nanomaterials should in particular take thefollowing measures in dealing with “nano -wastes”:10

• reduce waste volumes.• if possible treat the resulting nanomate-rial-containing wastes directly at the pointof origin with appropriate methods suchthat they lose their nano-features (for ex-ample by dissolving metallic nanomate-rials in suitable acid baths or sintering athigh temperatures).

• develop waste management schemes thatensure that nanowastes are separately col -lected, documented, packaged and fur-ther directed to disposal, whereby thesework steps should proceed with consistentquality.

• minimize nanomaterial emissions (dust oraerosols) into the environment. Nano -wastes should, to the extent possible, notbe collected and transferred as powderedpreparations but rather as dispersions,pastes, granulates, etc.

Currently, too little is known about the be-havior of ENMs in waste incineration plants.This leads to the recommendation not to dis-pose large quantities of nanowastes fromindus try and trade in such facilities.10 This,however, raises the question of viable alter-natives, such as chemo-physical treatmentmethods.

The special application of ENMs in indus-trial processes (e.g. filter or catalyst technolo-gies) enables ENMs to be collected in un-mixed form. Their use in consumer productssuch as cosmetics, textiles, paints and var-nishes, etc., however, leads to a diffuse dis-tribution. This considerably complicates sep-arate collection.3

Waste treatment in Austria

The European Waste Framework Directive11,which has been implemented in the Austri-an Waste Management Act (AWG 2002)12,is based on the following hierarchy:

1. waste prevention

2. preparation for re-use

3. recycling

4. other utilization (e.g. energy recovery)

5. disposal.

In Austria the targeted recycling of separate-ly collected waste fractions (paper, metals,plastics, glass) from municipal wastes is wellestablished.13 In 2009, 63% of the wasteswere collected for processing and recycling.The residual waste (from households and sim-ilar institutions) undergoes either mechani-cal-biological waste treatment (24.4%; basis2009) or thermal waste treatment in incin-eration plants (70.5%; basis 2009).14

In Austria the wastes must be pre-treated orrecycled, and only very small amounts aredirectly disposed. The residues from the wastetreatment plants (e.g. slag after incineration)as well as construction and demolition wasteare dumped. In many other EU countries,however, municipal wastes are largely or en-tirely disposed in landfills without pre-treat-ment (Fig. 3.).

Many products that are re-used in recyclingprocesses (for example electrical and elec-tronic equipment, metals, plastics, paper,cloth ing, etc.) can contain nanomaterials andthese can potentially be released. At leastfour different processes could lead to releas-es during recycling:16

2

Figure 2:Percentages of selected waste categories

in 2010 (Basis: 51.72 million tons)9

excavated materials

green waste, street cleaning residues,market waste ash, slag from thermal waste treatmentand combustion plants

wood waste

waste from construction

waste materials from trade and industry

municipal sewage sludge and faecal sludge waste from households and similar establishmentsother waste

No. 040en • August 2014

1. dust-like abraded material, which candisperse in the air as airborne particulatematter, can develop especially during tran -sport, during shredding and crushing, aswell as when tipping.

2. if the wastes are initially cleaned or cer-tain components dissolved or detached(for example a nano-coating on PET bot-tles), then nanomaterialsmight enter theliquid media and ultimately collect in thecleaning- and wastewater. The same holdstrue for the cleaning of facilities, equip-ment and floors, in which the dusts arecaptured in cleaning cloths and cleaningwater.

3. when incinerating products with nanoma-terial-containing substances, it cannot beexcluded that nanomaterials enter theflue-gases.

4. in readily soluble or strongly heated me-dia, an evaporation of nanomaterials isalso theoretically possible.

Experts from the “Hans Böckler Stiftung” ofthe Deutschen Gewerkschaftsbundes (Ger-man Trade Union Federation) therefore madean important recommendation in their work-ing paper on the significance of nanoma-terials in waste recycling16: future researchefforts on the risk potentials of nanomate-rials should be devoted to treatment process-es for potentially nanomaterial-containingconsumer products. The individual materi-al streams in the recycling chains should beexamined in detail regarding the types andamounts of nanomaterials being used. Thiswould help estimate the degree of potentialrisks.

Use of nanomaterials in products

Various nanomaterials are increasingly be-ing employed in products for industry, trade,and consumers. The online database of theAmerican Woodrow Wilson Center current-ly encompasses 1798 “nanoproducts” thatare available on the international market.17

A study on the Austrian market identified450 “nanoproducts” between late 2007 andApril 2009. The most entries are in the cat-egories “cosmetics” and “textiles”, which ac-cording to voluntary manufacturer informa-tion contain a number of nanomaterials(see18). The actually incorporated amountsof nanomaterials are unknown. Estimates ofproduction volumes are available, but theseoften differ considerably from one another(Tab. 1). Accordingly, SiO2 and TiO2 are the

nanomaterials with the highest productionvolumes worldwide and are probably themost common in products as well.

Several past NanoTrust Dossiers have dealtwith the various applications of nanomate-rials. The following therefore only briefly sum -marizes several product categories.

Textiles, for example for the outdoor sector,socks and underwear, can be impregnatedwith nanosilver to achieve an antimicrobialeffect. Impregnation with nanoparticulateTiO2 or ZnO acts as a UV filter, and SiO2has dirt- and water-repellent properties(see20). When these textiles are washed,nanomaterials can collect in sewage plantsvia wastewater. Studies on the behavior ofnanomaterials during the washing processare available only for silver, whereby the re-leased amounts vary considerably (see21). Iftextiles are chemically cleaned, then the pro-duced wastes, including lint, can also con-tain nanomaterials. No studies have beenconducted on nanoparticle releases duringthis process.22 Although used clothing is col-lected separately in Austria, nanomaterial-containing textiles are also partially disposedof via the municipal solid waste stream inincineration plants.

Cosmetics can contain carbon black (blackpigment), TiO2, ZnO, SiO2 in their nano -form, or in certain cases also fullerenes asradical scavengers. These nanomaterials canenter household waste in incompletely emp-

tied canisters and then be combusted in wasteincineration plants, or enter wastewater dur -ing washing or showering. In particular, thenanoparticulate UV filter TiO2, which is acommon component in sunscreen lotions(see23), can be released into the water whenpeople bath or swim. No information is avail -able on the exact amounts released, and on-ly few studies have been conducted on po-tential negative ecological effects; these stud -ies provide inconclusive evidence (see24).

In paints and varnishes, nanosilver, TiO2,ZnO, SiO2 or Al2O3 (aluminum oxide) areused as biocides, as UV protection or to im-prove scratch- and abrasion resistance (see25).Containers with remnant contents are dis-carded as household waste, as hazardouswaste or as construction wastes. Moreover,nanomaterials can also leach out of facadepaint and enter the soil and waterbodies viarainwater, or enter sewage treatment plantsthrough the sewer system.26

Cement-bound building materials (e.g. con -crete) can also contain nanomaterials, forexample SiO2 as aggregates to improvestrength and stability, or TiO2 based on itsphotocatalytic “self-cleaning effect” or its abil -ity to remove air pollutants (see27). Specialsun protection glazing for windows or elec-trochromic (automatically adjusting) windowglass to darken room interiors with nano -scale coatings of silver or wolfram oxide arestill niche products in the construction busi-

3

Figure 3: Municipal wastes according to treatment categories – inner-EU comparison15

Landfill Incineration Recycling Composting

No. 040en • August 2014

ness, but could find wider use in the future.Nanoparticles could be released with thedust produced when demolishing buildings.Such materials could also be released intothe air during temporary storage, during thetreatment process or when disposed in land -fills. They could also enter the groundwaterthrough wastewater or by leaching.28 No in-formation is available on these processes.

Nanomaterials composed of carbon, suchas CNTs, fullerenes or graphene, are – ac-cording to manufacturer specifications – in-corporated into the synthetics used in sportsequipment. In tennis rackets, for example,they can help increase tensile strength (see29).When disposed of in household waste, themajority of such products is incinerated inAustria. CNTs most likely burn completely insuch facilities, but it cannot be excluded thatsmall fractions enter the environment throughflume gases or solid residues (see30). In Aus-tria, household wastes must be pre-treated,but in other countries they are directly dis-posed in landfills (compare Fig. 3). A studyin the USA shows that CNTs – when thesecome into contact with other wastes in land-fills – are partially bound or retain their sta-bility.31 Leaching of CNTs and other “nano -wastes” depends strongly on the respectivelandfill conditions. No information is avail-able on the behavior of fullerenes or gra -phene.

Nanoparticulate crystals made of semi-con -ductor materials, so-called quantum dots,are increasingly being applied in the elec-tronics industry. Examples include moderntelevisions with LED backlighting but also theproduction of lamps (LED) and in highly ef-ficient thin-film solar cells. Based on their po-tential content of arsenic, cadmium, europi-

um, gallium, indium, tellurium, etc., LEDsshould be collected as “problematic waste”(hazardous waste) and not be discarded inhousehold garbage. The semi-conductorgallium arsenide is particularly problemat-ic due to the toxicity of arsenic. This is be-cause, in the absence of atmospheric oxy-gen and water, a very thin oxide layer canform on the surface of the material; it is high-ly toxic and could damage the environment.Quantum dots can contain numerous rare-earth metals, and resource policy consider-ations dictate that these should be recycled.The recycling processes, for example forLEDs, are currently still under developmentand very expensive.32 As provided for by theEU guide lines on waste electrical and elec-tronic appliances, LEDs must be taken backby the traders or manufacturers and prop-erly disposed of.

Behavior ofnanomaterials in wasteincineration plants

Little information is currently available abouthow nanomaterials behave in waste incin-eration plants or in landfills. Studies havebeen conducted on only a few materials, forexample on ceroxide nanoparticles that wereexperimentally introduced into an incinera-tion plant. The results show that these wereneither chemically nor physically altered bythe incineration process, but that they wereeffectively retained in the facility’s filters.Nanoparticles that bond with the solids inthe facility, however, ultimately end up withthe combustion residues in landfills. Thus,

the disposal problem in the case of stableENMs is merely shifted to the subsequentsteps in the waste treatment process.33

Studies in Switzerland show that only a tinyfraction (on average ca. 0.00079 percent byweight) of the filter dust of incineration plantsis present in the form of nanoparticles andthat these make up less than 10% of the to-tal particle counts. Model calculations re-vealed that most of the nanoparticles (na -nosilver, TiO2, ZnO) in the wastes (residualwastes, wood, sludge) are present in formof bottom ash34 and end up in landfills. Incontrast, CNTs are almost completely com-busted (94%)35.

The behavior of nanomaterials in waste in-cineration plants can currently be summa-rized as follows:36, 37

• When incinerated, nanomaterials can ei-ther be destroyed, converted into othernanomaterials (e.g. oxides, chlorides) orbe released unchanged.

• Nanomaterials in the size class 100 nmand larger are most efficiently removedin the filters of waste gas purification sys-tems.

• Nanomaterials smaller than 100 nm areonly partially retained by filters. An esti-mated up to 20% can be released.

• Incinerating nanomaterials can acceler-ate the formation or destruction of unde-sired by-products (e.g. polycyclic aromat-ic hydrocarbons).

• Nanomaterials can be retained in the sol-id wastes (ash, slag, filter residues) pro-duced by waste incineration plants. Aleach ing of nanomaterials from suchwastes, for example when subsequentlydumped in a landfill, should be avoided(landfill base sealing, leachate treatment,surface sealing etc.).

4

Table 1: Estimated global production volumes of different nanomaterials19

Nanomaterial Production volumes (in tons p.a.) Year

SiO2 1,590,000 2009

TiO2 700-61,000

50,000

44.000 (only USA)

1,450 (only Japan)

2007/2008

2010

2008

2019

ZnO 20-10.000

480 (only Japan)

2007/2008

2009

CeO2 10,000 2010

Al oxides 100 2003

ZrO2 2,500 2010

Metals 20 2007

Silver 4-560 2005/2008

Quantum dots < 100 kg 2001

Conclusions

Various nanomaterials are currently beingincorporated in a wide range of products.It remains largely unknown whether thesecan pose an environmental or health riskwhen they end up in waste treatment plantsor in landfills via various waste streams atthe end of their life cycle. In a precaution-ary approach, several experts and organ-izations have therefore formulated first rec-ommendations designed to minimize na -nomaterials in wastes. Future research ef-forts should increasingly focus on the dis-posal phase of „nanoproducts” in orderto better estimate potential risks.

No. 040en • August 2014

Notes and References1 Nanowerk Nanomaterials Database. nanowerk.com/nanomaterial-database.php.

2 NanoTrust Dossier Nr. 026en.3 SRU, Sachverständigenrat für Umweltfragen,2011, Vorsorgestrategien für Nanomaterialien,Sondergutachten, Erich Schmidt Verlag, page 89.umweltrat.de/SharedDocs/Downloads/DE/02_Sondergutachten/2011_09_SG_Vorsorgestrategien%20f%C3%BCr%20Nanomaterialien.pdf?__blob=publicationFile.

4 NanoTrust Dossier Nr. 019en. 5 Wiechmann, B., Dubbert, W., 2011, Umwelt -aspekte von Nanoabfällen, Informationsdienstfür die Abfallwirtschaft in Brandenburg undBerlin, Sonderabfallgesellschaft Brandenburg/Berlin mbH, forum IV-2011. sbb-mbh.de/fileadmin/media/publikationen/sbbforum/forum-neu/2011/sbb-forum-2011-4-1.pdf.

6 Boldrin, A., et al., 2014, Environmental expo-sure assessment framework for nanoparticlesin solid waste. Journal of Nanoparticle Research16, 1-19.

7 See Boldrin et al. (EN 6), page 4.8 Mudgal, S. et al., 2011, Study on coherenceof waste legislation. Final Report. EuropeanCommission (DG ENV). 11 August 2011.

9 Bestandsaufnahme der Abfallwirtschaft in Ös -terreich. Statusbericht 2012. Umweltbundes -amt, Wien, im Auftrag des BMLFUW, page 7.bmlfuw.gv.at/dms/lmat/umwelt/abfall-ressourcen/bundes-abfallwirtschaftsplan/bawp2011/Statusbericht-2012---Endbericht_komplett/Statusbericht%202012%20-%20End-bericht_komplett.pdf.

10 Tellenbach-Sommer, M., 2010, Entwurf Kon -zeptpapier, Umweltverträgliche und sichere Ent -sorgung von Abfällen aus Herstellung sowieindustrieller und gewerblicher Verarbeitung vonsynthetischen Nanomaterialien, Arbeitsgruppe„Entsorgung von Nanoabfällen“, Commissio -ned by: BAFU. bag.admin.ch/nanotechnologie/12171/12177/index.html?lang=de&download=NHzLpZeg7t,lnp6I0NTU042l2Z6ln1acy4Zn4Z2qZpnO2Yuq2Z6gpJCKeIR5e2ym162epYbg2c_JjKbNoKSn6A—.

11 Directive 2008/98/EG of 19 November 2008on wastes and the repealing of certain direc-tives.

12 Waste management Act 2002 (Abfallwirtschafts -gesetz 2002 – AWG 2002), Federal law.

13 Neubauer, Ch., Walter, B., 2008, Behandlungvon gemischten Siedlungs- und Gewerbeab -fällen in Österreich, Betrachtungszeitraum 2003bis 2007, Umweltbundesamt, Report REP-0225.umweltbundesamt.at/fileadmin/site/publikationen/REP0225.pdf.

14 Federal Waste Management Plan 2011, Vol-ume 1, page 45, BMLFUW. bundesabfallwirtschaftsplan.at/dms/bawp/BAWP_Band_1_EN.pdf.

15 Blumenthal, K., 2011, Generation and treat-ment of municipal waste, Eurostat, Statistics infocus 31/2011, page 5. epp.eurostat.ec.europa.eu/cache/ITY_OFFPUB/KS-SF-11-031/EN/KS-SF-11-031-EN.PDF.

16 Struwe, J., Schindler, E., 2012, Bedeutung vonNanomaterialien beim Recycling von Abfällen,Arbeitspapier 270, Hans Böckler Stiftung. boeckler.de/pdf/p_arbp_270.pdf.

17 The Project on Emerging Nanotechnologies,Woodrow Wilson International Center for Schol-ars, Consumer Products Inventory. nanotechproject.org/cpi/products.

18 NanoTrust Dossier Nr. 009. 19 Table from: Möller, M. et al., 2013, Nanoma-terialien: Auswirkungen auf Umwelt und Ge -sundheit, page 53, TA-Swiss 60/2013: Zentrumfür Technikfolgen-Abschätzung, vdf Hochschul-verlag AG an der ETH-Zürich. vdf.ethz.ch/service/3559/3560_Nanomaterialien_OA.pdf.

20 NanoTrust Dossier Nr. 015en.21 NanoTrust Dossier Nr. 010en. 22 See Möller et al. (EN 19), page 178.23 NanoTrust Dossiers Nr. 008en and Nr. 033en.24 NanoTrust Dossiers Nr. 027en.25 NanoTrust Dossier Nr. 020en.26 See Möller et al. (EN 19), page 179.27 NanoTrust Dossier Nr. 032en.28 See Möller et al. (EN 19), page 182.29 NanoTrust Dossier Nr. 022en.

30 NanoTrust Dossier Nr. 024en. 31 Lozano, P. et al, 2012, Single-walled carbonnanotube behavior in representative matureleachate. Waste Management 32: 1699-1711.

32 Steinfeldt, M. et al., 2004, Nachhaltigkeits -effekte durch Herstellung und Anwendung na -notechnologischer Produkte, Schriftenreihe desIÖW, 177/04. ioew.de/uploads/tx_ukioewdb/SR177.pdf.

33 Walser, T. et al., 2012, Persistence of engineerednanoparticles in a municipal solid-waste incin-eration plant, nature nanotechnology letters,Vol. 7, 520-524.

34 Bottom ash refers to ash that accumulates inthe combustion part (the bottom or grate) ofthe incineration facility.

35 Müller, N.C., et al., 2012, Nanomaterials inwaste incineration and landfills, EMPA. empa.ch/plugin/template/empa/*/124646.

36 Roes, L. et al., 2012, Preliminary evaluationof risks related to waste incineration of poly-mer nanocomposites, Science of the Total En-vironment 417-428, 76-86.

37 Vejerano, E. P. et al., 2013: Emissions of Poly-cyclic Aromatic Hydrocarbons, Polychlorinat-ed Dibenzo-p-Dioxins, and Dibenzofurans fromIncineration of Nanomaterials. Environmen-tal Science & Technology 47: 4866-4874.

5

MASTHEAD:

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Editor: Institute of Technology Assessment (ITA); Strohgasse 45/5, A-1030 Vienna; www.oeaw.ac.at/ita

Mode of publication: The NanoTrust Dossiers are published irregularly and contain the research results of the Institute of Technology Assessment in the framework of its research project NanoTrust. The Dossiers are made available to the public exclusively via the Internet portal “epub.oeaw” :epub.oeaw.ac.at/ita/nanotrust-dossiers

NanoTrust-Dossier No. 040en, August 2014: epub.oeaw.ac.at/ita/nanotrust-dossiers/dossier040en.pdf

ISSN: 1998-7293

This Dossier is published under the Creative Commons (Attribution-NonCommercial-NoDerivs 2.0 Austria) licence: creativecommons.org/licenses/by-nc-nd/2.0/at/deed.en