Environmental (Ecological) Risk Assessment for Nanomaterials

Dana Kühnel (UFZ)

David Rickerby (JRC)

Summer School, Tallin,

16.-17.6.2014

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

Perspectives of ERA

Fundamental principles of RA

EFFECT EXPOSURE H

A

Z

A

R

D

RISK

Release

Distribution

Fate

Degradation

Bioavailability

Dose

Organisms (Algae,

fish, water flea…)

Endpoints (growth,

survival, mobility,

reproduction,…)

Probability

Protection/Management

Cost-benefit

Fundamental principles of RA

Key steps in risk assessment:

1. Problem formulation

2. Hazard identification

3. Release assessment

4. Exposure assessment

5. Risk estimation

Ecological Risk Assessment

PEC: predicted environmental concentration

PNEC: predicted no effect concentration

Exposure assessment → PEC

Effect assessment → NOEC → PNEC

(representative species)

Assessment factors

NOEC → PNEC

Risk evaluation

PEC vs. PNEC

PEC/PNEC > 1

Possible risk

PEC/PNEC < 1

No risk

PEC

Exposure assessment → PEC

From ENM to an effect

ENM

Release

Transport Transformation

Exposure

Dose

Effect Toxicology – Effect?

Risk of Release and Distribution Routes

8

●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

• production

• transport

• storage

• distribution

• use phase

• final disposal

Releases into the environment can take place from processes at any stage of the life cycle:

Technical Guidance Document on Risk Assessment, European Chemical Bureau, 2003

Potential Life Cycle Scenarios

Page 10

Indium tin oxide (ITO)

Lacquer and plastics additive

Touch screens

2.0

TiO2

Textiles

Skin care, sun screen

Anti-fogging agents

Cobblestones

Facade and wall colour

Film

Photovoltaic cell

Silver

Textiles

Wound dressings

Free Embedded

Release of nanomaterials

Pathways for Release into the Environment

11

●Release may occur during production, transport, storage, distribution, use and final disposal

S. Friedrichs and J. Schulte, Sci. Technol. Adv. Mater. 8 (2007) 12-18

• From textiles equipped with Ag for antibacterial purposes

• Release of nAg or ions?

Benn et al. (2008) ES&T 42, 4133–4139.

Example I: Washing off of nAG

Example II: nTiO2 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): 233-239

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) 322-323

• 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 Kow

• Several test guidelines are used to study these processes → suitable for NM

From Release to Exposure Environmental Fate Modelling

Sanchis et al. (2012) ES&T 46, 1335-1343.

• Fulleres (C60 and C70) were detected in the Mediterranean atmosphere (ng/m3)

• Occurence can be related to industrial activity, but the release/emission path is unclear

• Probably side products of combustion processes, unintentially produced NM?

Example : Occurence of fullerens

Predicted Environmental Concentrations

Predictions are based on:

- production volumes

- categories of products containing nanomaterials

- paths of particle release Mueller and Nowack (2008) Environ. Sci. Technol. 42: 4447-4453.

Sun TY et al. (2014) Environ Pollut 185, 69-76.

NM Soil Sludge treated soil

Surface water

STP effluent

STP sludge

sediment air Year

Nano-TiO2 1.28 89.2 0.015 3.47 136 358 2008

0.13 1200 0.53 16 170 1.9 0.001 2014

Nano-ZnO 0.093 3.25 0.010 0.432 17.1 2.90 2008

0.01 0.01 0.09 2.3 24 0.32 <0.001 2014

Nano-Ag 22.7 1581 0.764 42.5 1.68 952 0.008 2008

1.2 0.11 0.66 0.17 0.02 2.3 0.003 2014

CNT 1.51 73.6 0.004 14.8 0.062 241 0.003 2008

5.1 0.99 0.32 4.0 0.15 0.79 0.02 2014

C60 0.058 2.2 0.017 5.2 0.012 17.1 2008

0.10 0.62 0.11 1.7 0.09 0.37 0.001 2014

Unit µg kg-1 y1 µg kg-1 y1 µg l-1 µg l-1 mg kg-1 µg kg-1 y1 µg m-3

Predicted Environmental Concentrations

Sun TY et al. (2014) Environ Pollut 185, 69-76.

Modelled

concentration NM

Modelled concentration

pigments

Measured

concentration

conventional

material

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

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)

Ecological Risk Assessment

PEC: predicted environmental concentration

PNEC: predicted no effect concentration

Exposure assessment → PEC

Effect assessment → NOEC → PNEC

(representative species)

Assessment factors

NOEC → PNEC

Risk evaluation

PEC vs. PNEC

PEC/PNEC > 1

Possible risk

PEC/PNEC < 1

No risk

PEC

Effect assessment → NOEC → PNEC

(representative species)

Ecotoxicity Testing

• Representative species (for the different compartments)

• According to test guidelines (OECD, ISO)

• Dose-response relationships (→ NOEL)

• High variation in LC50

• 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, 6288-6296.

Ranges of toxicity – nAg in Daphnia magna

Ranges of toxicity – CNT Aquatic toxicity classification

mg/L

Not toxic > 100

Harmful 10-100

Toxic 1-10

Very toxic 0.1-1

Extremely toxic < 0.1

Comparison of CNT – studies

154 studies in total

78 11 58

Interferences with test systems

• shading (relevant for autotrophic organisms)

Schwab et al. (2011) ES&T, 45, 6136–6144.

Interferences with test systems

• Binding of components in the test media (e.g. fluorescent dyes)

Wörle-Knirsch et al, NANO LETTERS, 2006 6(6):1261-1268

CNT

MTT WST-1

control

As prepared

purified

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) 012037

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, 347–353.

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

Ecotoxicology Fate & Behaviour

Aquatic tests

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)

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)

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)

D. Kühnel & C. Nickel (2014) Science of The Total Environment, 472, 347–353.

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

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

Page 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)

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)

LEGISLATION OF NM

REACh (Industrial chemicals)

• Amendments in Exposure assessment

Legislation

Meesters et al. 2013 Integr Environ Assess Manag 9(3): e15-e26

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

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 http://echa.europa.eu/regulations/biocidal-products-regulation/understanding-bpr

http://www.umweltbundesamt.de/sites/default/files/medien/378/publikationen/datenblatt_nanoprdukte_textilien_0.pdf

Labelling in cosmetic products in EU mandatory

LEGISLATION OF NM

´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. 2012 Nanotox. 6(2): 196-212.

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

´Nano´-specific strategies and tools

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

http://www.nanoriskframework.com

● 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

http://www.bag.admin.ch/themen/chemikalien/00228/00510/05626

Nano-specific RA-tools Example 2: Swiss Precautionary Matrix

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

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

References / Further Reading

• Technical Guidance Document on Risk Assessment (European Chemical Bureau, 2003)

• http://reports.eea.europa.eu/GH-07-97-595-EN-C2/en/riskindex.html

• C. Ostiguy et al. J. Phys. Conf. Series 151 (2009) 012037

• S. Friedrichs and J. Schulte, Sci. Technol. Adv. Mater. 8 (2007) 12-18

• M. Scheringer, Nature Nanotechnol. 3 (2008) 322-323

• Technical Guidance Document on Risk Assessment, European Chemical Bureau, 2003

• http://www.oecd.org/department/0,3355,en_2649_34373_1_1_1_1_1,00.html

• http://www.nanoriskframework.com

Page 46

Thank you for your attention! Questions?

http://www.oecd.org/department/0,3355,en_2649_34373_1_1_1_1_1,00.html

●International Test Guidelines on

physical-chemical properties,

ecotoxicity, environmental fate,

human health effects developed

by the OECD

Environmental Risk Management