Environmental (Ecological) Risk Assessment for Nanomaterials

Transcription

1 Summer School, Tallin, Environmental (Ecological) Risk Assessment for Nanomaterials Dana Kühnel (UFZ) David Rickerby (JRC)

2 Agenda 1. Fundamentals of ERA 2. Release of NM 3. Fate & Exposure of NM 4. Ecotoxicity / Hazard 5. Risk management 6. Regulation (REACh and Co.) 7. Nano -specific RA tools

3 Perspectives of ERA

4 Fundamental principles of RA EFFECT Organisms (Algae, fish, water flea ) Endpoints (growth, survival, mobility, reproduction, ) H A Z A R D EXPOSURE Release Distribution Fate Degradation Bioavailability Dose RISK Probability Protection/Management Cost-benefit

5 Fundamental principles of RA Key steps in risk assessment: 1. Problem formulation 2. Hazard identification 3. Release assessment 4. Exposure assessment 5. Risk estimation

6 Ecological Risk Assessment Exposure assessment PEC Effect assessment NOEC PNEC (representative species) Exposure Assessment assessment factors PEC NOEC PNEC PEC/PNEC < 1 No risk PEC Risk evaluation PEC vs. PNEC PEC/PNEC > 1 Possible risk PEC: predicted environmental concentration PNEC: predicted no effect concentration

7 From ENM to an effect Transport Transformation Exposure Release Dose ENM Toxicology Effect? Effect

8 Risk of Release and Distribution Routes Need to understand the relationship between the local emission routes and the distribution processes for different environmental compartments Specific fate and distribution models are applicable for individual compartments 8

9 Potential Life Cycle Scenarios Releases into the environment can take place from processes at any stage of the life cycle: production transport storage distribution use phase final disposal Technical Guidance Document on Risk Assessment, European Chemical Bureau, 2003

10 Release of nanomaterials Free Embedded Silver Textiles Wound dressings TiO 2 Textiles Skin care, sun screen Anti-fogging agents Cobblestones Facade and wall colour Film Photovoltaic cell Indium tin oxide (ITO) Lacquer and plastics additive Touch screens Page

11 Pathways for Release into the Environment Release may occur during production, transport, storage, distribution, use and final disposal S. Friedrichs and J. Schulte, Sci. Technol. Adv. Mater. 8 (2007)

12 Example I: Washing off of nag From textiles equipped with Ag for antibacterial purposes Release of nag or ions? Benn et al. (2008) ES&T 42,

13 Example II: ntio 2 in facade paint Release during weathering Modified NM reach the environment: paint matrix Environmental exposure not to as-produced NM Kaegi et al. (2008) Environmental Pollution 156 (2):

14 From Release to Exposure Environmental Fate Modelling The models calculate concentrations in environmental media and the mass fluxes of the substance between these media Need to identify properties of nanomaterials that govern distribution processes to derive input parameters for the models M. Scheringer, Nature Nanotechnol. 3 (2008)

15 From Release to Exposure Environmental Fate Modelling Physical-chemial characteristics of NM will determine their fate (in which compartments an accumulation of NM is observed) transport, distribution, accumulation, transformation processes for NM in the different compartments (soil, sediments, surface water, ground water) need to be further studied The physical-chemical characteristics differ from that of chemicals and hence the parameters of the models need to be adopted, e.g. log K ow Several test guidelines are used to study these processes suitable for NM

16 Example : Occurence of fullerens Fulleres (C 60 and C 70 ) were detected in the Mediterranean atmosphere (ng/m 3 ) Occurence can be related to industrial activity, but the release/emission path is unclear Probably side products of combustion processes, unintentially produced NM? Sanchis et al. (2012) ES&T 46,

17 Predicted Environmental Concentrations Predictions are based on: - production volumes - categories of products containing nanomaterials - paths of particle release Sun TY et al. (2014) Environ Pollut 185, Mueller and Nowack (2008) Environ. Sci. Technol. 42: NM Soil Sludge treated soil Surface water STP effluent STP sludge sediment air Year Nano-TiO Nano-ZnO < Nano-Ag CNT C Unit µg kg -1 y 1 µg kg -1 y 1 µg l -1 µg l -1 mg kg -1 µg kg -1 y 1 µg m -3

18 Predicted Environmental Concentrations Modelled concentration NM Modelled concentration pigments Measured concentration conventional material Sun TY et al. (2014) Environ Pollut 185,

19 Fate and transformation Little knowledge on transformation and degradation of NM e.g. dissolution processes / degradation of arganic coating Sorption of organic materials present in the environment will influence fate

20 Exposure Unsufficient measurement techniques for complex environmental media (especially for water and soil) the parameters of importance for the environmental behaviour of NM are not clear yet (e.g. surface modifications are not considered)

21 Ecological Risk Assessment Exposure assessment PEC Effect assessment NOEC PNEC (representative species) Effect assessment NOEC PNEC Assessment factors (representative NOEC PNEC species) PEC/PNEC < 1 No risk PEC Risk evaluation PEC vs. PNEC PEC/PNEC > 1 Possible risk PEC: predicted environmental concentration PNEC: predicted no effect concentration

22 Ecotoxicity Testing Representative species (for the different compartments) According to test guidelines (OECD, ISO) Dose-response relationships ( NOEL)

23 Ranges of toxicity nag in Daphnia magna High variation in LC 50 Different types of NM and test protocols Likewise observed for the nag we worked with in NanoValid Beispiel aus Supplement: Poynton et al. (2012). ES & T 46,

24 Ranges of toxicity CNT Aquatic toxicity classification mg/l Not toxic > 100 Harmful Toxic 1-10 Very toxic Extremely toxic < 0.1

25 Comparison of CNT studies 154 studies in total

26 Interferences with test systems shading (relevant for autotrophic organisms) Schwab et al. (2011) ES&T, 45,

27 Interferences with test systems Binding of components in the test media (e.g. fluorescent dyes) MTT WST-1 CNT control As prepared purified Wörle-Knirsch et al, NANO LETTERS, (6):

28 Uncertainties in the Risk Assessment for Nanomaterials Quantitative risk assessment depends on exposure limits based on dose-response relationships and the quantitative evaluation of the exposure For nanomaterials neither the hazards or the exposure can be quantified This leads to major uncertainties and a need for nanospecific risk assessment C. Ostiguy et al. J. Phys. Conf. Series 151 (2009)

29 Towards the improvement of RA procedures Are the guidelines, developed for traditional chemicals suitable for the testing of NM? Specific NM properties not considered, e.g. agglomeration, sorption Amendments necessary? OECD-Working Party on Manufactured Nanomaterials (WPMN), expert meetings D. Kühnel & C. Nickel (2014) Science of The Total Environment, 472,

30 Scope of the expert meeting Discuss suitability of TGs relevant to ecotoxicity and environmental fate testing of NM, compartments water and soil & sediment Provide recommendations to WPMN on (1) the need for updating TGs or developing new ones, and (2) guidance needed for NM Aquatic tests Ecotoxicology TG 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test) TG 202 (Daphnia sp. Acute Immobilisation Test) TG 211 (Daphnia magna Reproduction Test) TG 225 (Sediment-Water Lumbriculus Toxicity Test Using Spiked Sediment) Fate & Behaviour TG 105 (Water solubility) TG 305 (Bioconcentration: Flow-through Fish Test ) (additionally discussed: GD 24 and biodegradation tests in general) Soil & sediment tests TG 222 (Earthworm Reproduction Test (Eisenia fetida/eisenia andrei)) TG 225 (Sediment-Water Lumbriculus Toxicity Test Using Spiked Sediment) TG 106 (Adsorption) TG 312 (Leaching in Soil Columns) TG 315 (Bioaccumulation in Sediment-dwelling Benthic Oligochates) TG 317 (Bioaccumulation in Terrestrial Oligochaetes)

31 D. Kühnel & C. Nickel (2014) Science of The Total Environment, 472, Testing steps to consider Dispersion of NM in water or media (e.g. enery input) Application of NM to the test Physical-chemical characterisation before, during and after the test NM behaviour during the tests (e.g. sedimentation), test duration Interactions with organisms, media components Detection of NM in organisms or environmental matrices High variations in existing protocols for the different NM Many analytical limitations (e.g. NM charact. in soils)

32 Expert recommendations The majority of TGs was considered as generally applicable to NMs Suggestions for nano-specific amendments: application of NM to the test, behaviour of NM during the test, data analysis, selection of test media For several guidelines, critical points were identified, where current knowledge does not justify a recommendation, but which need future clarification The development of new TGs suggested

33 Data gaps and research needs Physical-chemical characterisation of NM was considered essential for all subsequent steps of testing Many data gaps are due to inappropriate methods for NM Chronic tests

34 LEGISLATION OF NM Few regulations specifically apply to NM: For chemicals, extensive testing before application is mandatory The size of a material alone is so far no basis for RA Hence, no specific procedures for NM are compulsory (with the exception of the Biocidal Products Directive 98/8/EEC) Page 34

35 LEGISLATION OF NM REACh (Industrial chemicals) no explicit regulation for `nano -size, the need for adoptation of the legislation is under debate REACH implementation Project on Nanomaterials (RIPoN) `Principle of Similarity` (Use of data derived with similar substances, e.g. bulk material possible)

36 Legislation REACh (Industrial chemicals) Amendments in Exposure assessment Meesters et al Integr Environ Assess Manag 9(3): e15-e26

37 LEGISLATION OF NM REACh (Industrial chemicals) lower tonnage thresholds for different REACH obligations Adaptation of REACh requirements and test performance to different physico-chemical characteristics of different nanoforms of the same substance Schwirn et al. Environmental Sciences Europe 2014, 26:4

38 LEGISLATION OF NM EU-Biocidal Products Regulations (came into force by 1. Sep. 2013) considers `nano, NM in biocidal products need to under go a special assessment More strict demands for approval / permission, labelling required anoprdukte_textilien_0.pdf Labelling in cosmetic products in EU mandatory

39 Nano -specific strategies and tools Nano Risk Framework Precautionary Matrix for Synthetic Nanomaterials (Vorsorgeraster) Risk Assessment of Manufactured Nanomaterials NanoCommission Assessment Tool Precautionary Strategies for Managing Nanomaterials SafeNano Cenarios Work Health & Safety Assessment Tool for Handling Engineered Nanomaterials Stoffenmanager Nano NanoSafer ANSES Grieger et al Nanotox. 6(2):

40 Nano -specific strategies and tools Not implemented in legislation and hence not regulatory binding Preliminary assessments, e.g. to deduce occupational safety measures (Aim: Precaution!) Many uncertainties (release, exposure, persitence, transport, transformation, ecotoxicology), as these processes are poorly understood for NM

41 Nano-specific RA-tools Example 1: Nano Risk Framework Traditional risk-assessment paradigm similar to that used by the US EPA Complicated to apply - requires data on physical-chemical properties, hazards, exposures, ecotoxicity, and environmental fate

42 Nano-specific RA-tools Example 2: Swiss Precautionary Matrix Enables assessment of the need for nanospecific precautionary measures and identification of potential risks in production, use and disposal Simpler to apply provides an early warning capability enabling the risk potential to be classified to determine what action is appropriate

43 Risk assessment NM? exposure assessment Release depends of NM application No data on environmental concentrations Predicted values Development of methods suitable for NM hazard assessment Several studies, high variance Uncertainties Amendments in methodology necessary

44 Wrap up: risk assessment nanomaterials? Currently low environmental concentrations of NM Predicted concentrations below effect concentrations determined in lab experiments But: high uncertainties Research needs in many areas Release and exposure data for NM Nanospecific amendments in test protocols for toxicology Adaptation of models (release, QSAR, LCA) Amendments in laws & regulations necessary

45 References / Further Reading Technical Guidance Document on Risk Assessment (European Chemical Bureau, 2003) C. Ostiguy et al. J. Phys. Conf. Series 151 (2009) S. Friedrichs and J. Schulte, Sci. Technol. Adv. Mater. 8 (2007) M. Scheringer, Nature Nanotechnol. 3 (2008) Technical Guidance Document on Risk Assessment, European Chemical Bureau, html

46 Thank you for your attention! Questions? Page 46

47 Environmental Risk Management International Test Guidelines on physical-chemical properties, ecotoxicity, environmental fate, human health effects developed by the OECD