Case studies to explore the applicability of developed tools to industrial substances

Transcription

1 Case studies to explore the applicability of developed tools to industrial substances Contributions by A Ghanem (Solvay), P Hallegot (L Oréal), A Mech (JRC), R Peters (RIKILT), D Rosenkranz (BfR), W Wohlleben (BASF) and external stakeholders via VCI: M Voetz (Bayer), U Hempelmann (Lanxess), B Braun (Evonik) 1

2 3 categories of Case Studies 1. NanoDefine Materials extensively tested in NanoDefine already Case study uses data generated in NanoDefine WP3-4-5 IRMM384 CaCO3 (Solvay) IRMM385 Kaolin (BASF) BAM13a sunscreen (L Oréal) IRMM-389 BMA copolymer (RIKILT) 2. Additional OECD sponsorship program materials from the JRC repository Case study uses existing data obtained by methods that are not in contradiction to NanoDefine. ZnO NM113 (JRC) MWCNT (BfR) 3. Additional materials with challenges not represented by WP1 materials Case study uses new data, to be generated according to NanoDefine guidance at own expenses of the contributors. Performed in-kind by external contributors from the first NanoDefine-VCI workshop Plastics granulates (M Voetz, Bayer and NanoDefine advisory board) Iron oxides (U. Hempelmann, Lanxess) Silica, pyrogenic (B. Braun, Evonik) 2

3 Updated (2017) Decision Flow Scheme All existing and novel materials N a n o D e f i n e Nanomaterial by EU definition (SWCNT, fullerenes, graphene) Basic classification Basic sorting of materials according to the EU definition Possible Nanomaterial Nanomaterial by EU definition (non-particular materials e.g. proteins and nanostructured materials) Prioritize route (Descriptive EM/Dispersion )* *only if necessary; allows to acquire basic knowledge on the sample Measurement as powder Measurement as dispersion BET-Measurement Tier 1 dispersion method Tier 1 Screening Nanomaterial by EU definition > 6 Determination of shape (descriptive EM) Accept? Nanomaterial by EU Definition x 50 > 100 * for irregular/mixture of shapes apply most conservative cut-off value accept homogene ous* x 50 > 250 > 8/16/24 Tier 2 Confirmatory > 20/40/60 Accept? Nanomaterial by EU Definition Nanomaterial by EU definition x E-Microscopy Verify size with initial descriptive EM (or go to BET if possible) x 50 > 100 Size ok* Nanomaterial by EU definition *Size OK if x 50 in dispersion is consistent below a factor 2 with a dispersion-free method such as BET or descriptive EM

4 Case studies on substances (which is the intended application of decision flow scheme and e-tool) 4

5 CaCO 3 IRMM-384 (fine grade) All existing and novel materials Basic classification Basic sorting of materials according to the EU definition Possible Nanomaterial Prioritize route Tier 1 Screening Measurement as powder BET-Measurement > 6 from Table 1 of the paper on submitted to JNR : =15 m 2 /cm 3 (<16 m 2 /cm 3 ) Shape (SEM) = rod (cigar-like) d()=267 nm Determination of shape (descriptive EM) Tier 2 Confirmatory > 10/20/30 Nanomaterial by EU definition A. Ghanem (Solvay) Image: Coda-Cerva

6 CaCO 3 IRMM-384 (fine grade) Measurement as dispersion Tier 1 dispersion method Tier 1 Screening x 50 > 100 Ac-cuv-RI (from BASF) : D50(N) = nm Verify plausibility (descriptive EM) * OK if x 50 in dispersion is consistent with a dispersion-free method such as BET or SEM (within a factor 2) Dispersion OK? * SEM by measuring manually 16 particles on the SEM micrograph f Figure 1f of the paper on submitted to JNR : Feret (min) = 171 nm Tier 2 Confirmatory E-Microscopy x 50 > 250 x 50 > 100 SEM from the paper on submitted to JNR : Feret(min) = 157 nm Nanomaterial by EU definition A. Ghanem (Solvay)

7 Kaolin IRMM-385 instead of check dispersability, in reality we use pre-existing knowledge to expect successful validity/plausibility checks by either route of measurement. Measurement as powder BET-Measurement > 6 Tier 1 Screening Determination of shape (descriptive EM) > 10/20/30 Tier 2 Confirmatory > 20/40/60 W. Wohlleben (BASF) Accept? Nanomaterial by EU Definition 42 m²/cm³ (corresponding to platelet thickness = 48 nm) Platelet thickness: 37 nm

8 Case Study Kaolin in e-tool: input 8

9 Case Study Kaolin in e-tool: method recommendations 9

10 Case Study Kaolin in e-tool: output 10

11 Case studies on additional substances (using NanoDefine guidance) 11

12 Borderline nano/non-nano iron oxide 3 (nano)forms of Fe 2 O 3 Data covers both powder + mobility routes both borderline TEM with N=1000 Adsorption data TEM data (Feret diameter) LS Samples Densit y BET m²/g Sw m²/g m²/cm³ Median/min nm Median/max nm Shape Aspect ratio % particles D[4,3] nm D[1,0] nm g/cm³ <100 nm Fe2O3 Red Rhom/irr Fe2O3 Red Rhom/irr Fe2O3 Red Rhom/irr Example Fe2O3 Red 1 U. Hempelmann (Lanxess) 12

13 Case study Polycarbonate Granulate Measurement as powder BET-Measurement < 0,04 m²/g ; VSAA<0,048m²/cm³ > 6 Tier 1 Screening Nanomaterial by EU definition Thermoplastic granulates are particulate materials with large size in volume metrics (millimeters) and an intermediate : At following steps of the value chain, the granulates are molten for injection molding of macroscopic (millimeter to meter) components and parts. The polymer melt may contain pigments, but here only the external dimension is relevant. M. Voetz (Bayer) kunststoff-schweiz.ch

14 Another case of macroscopic particles IRMM-389 Basic methacrylate copolymer e-tool recommends suitable methods, results indicate non-nano : R. Peters (RIKILT) 14

15 Challenges for decision flow scheme and e-tool: conceptual ambiguity of constituent particles 15

16 Case study pyrogenic silica Measurement as powder Measurement as dispersion Tier 1 Screening BET-Measurement > 6 Tier 1 dispersion method x 50 > 100 t easily dispersible, but Tier 1_powder indicates nanomaterial Determination of shape (descriptive EM) Verify plausibility (descriptive EM or BET) Tier 2 Confirmatory > 20/40/60 Accept? > 10/20/30 Dispersion OK? * Depending on the consideration of either primary or constituent particles and the diameter used, x50 can be considered either above or below 100 nm Nanomaterial by EU Definition x 50 < 100 E-Microscopy x 50 > 100 Nanomaterial by EU definition B. Braun (Evonik)

17 Case studies on additional substances (using pre-existing data) 17

18 ZnO NM113 with pre-existing EM: inconclusive Basic classification Measurement as powder Possible Nanomaterial Prioritize route BET- Measurement Tier 1 Screening > 6 Determination of shape (descriptive EM) > 10/20/30 Tier 2 Confirmatory > 20/40/60 Inconclusive because EM method from OECD/JRC report not known if compliant with NanoDefine (A. Mech, JRC) Nanomaterial by EU Definition x 50 < 100 E-Microscopy x 50 > 100 Nanomaterial by EU definition

19 Case Study ZnO NM113 in e-tool: output as borderline confirms manual assessment 21

20 Case study: Carbon Nano Tubes (CNTs) All existing and novel materials Nanomaterial by EU definition (CNT, fullerenes, graphene) Basic classification Basic sorting of materials according to the EU definition a) c) a) c) a) Single wall (left) and multi walled (right) CNTs; b) fullerene; c) graphene. b) JRC Science and Policy Report Towards a review of the EC Recommendation for a definition of the term "nanomaterial Part 2: Assessment of collected information concerning the experience with the definition By derogation [ ], fullerenes, graphene flakes and single wall carbon nanotubes with one or more external dimensions below 1 nm should be considered as nanomaterials. For fullerenes, graphenes and SWCNTs no size distribution are needed. F. Zhang et al.; nature communications; March 2016; DOI: /ncomms11160 J. H. Lehman et al.; Carbon 49 (2011); D. Rosenkranz (BfR)

21 What if the derogation is not considered? Case study: Carbon Nano Tubes (CNTs) All existing and novel materials Nanomaterial by EU definition (SWCNT, fullerenes, graphene) Basic classification Basic sorting of materials according to the EU definition Possible Nanomaterial Prioritize route (Descriptive EM/Dispersion )* Tier 1 Screening Nanomaterial by EU definition * for irregular/mixture of shapes apply most conservative cut-off value Measurement as powder BET-Measurement > 6 > 8/16/24 Determination of shape (descriptive EM) accept homogene ous* Nanomaterial by EU definition - BET measurements for pure MWCNT can be used in a good approximation to estimate the fiber diameter with a mismatch factor of (W. Wohlleben et al.; J Nanopart Res; 19; 61; 2017) - BET surface for MWCNT mostly > 100 m²/cm³ - for functionalized and spiked MWCNT BET can also be used, at the descriptive EM step the diameter of MWCNT should be randomly checked CNT spiked with nano particles Z. Jiang and Z.-J. Jiang; nanotechnology and Nanomaterials: Carbon Nanotubes Growth and Applications ; Chapter 24; Book edited by Dr. Mohammad Naraghi, August; 2011 > 20/40/60 Tier 2 Confirmatory Accept? Nanomaterial by EU Definition x 50 < 100 E-Microscopy D. Rosenkranz (BfR) 23

22 Case Study mwcnt in e-tool: robust against incomplete description of material 24

23 Case Study mwcnt in e-tool: robust against incomplete description of material 25

24 Case Study mwcnt in e-tool: robust against incomplete description of material 26

25 Case studies performed manually and by e-tool: CONCLUSIONS Wide diversity of case studies: organic / inorganic; academia / industry / regulators nano / borderline / non-nano particles / fibers / platelets Reliability: case studies explored both Tier 1 routes (powder and mobility), and benchmarked against a Tier 2 method (SEM or TEM). Zero cases of inconsistent classification, but two cases remained inconclusive. Sources of ambiguity: reliability of pre-existing data (esp. EM) and their analysis/interpretation limits of the linear, hierarchical scheme on complex shapes (pyr. silica) and articles (sunscreen). Alternatives: weight-of-evidence approaches Decision Tree has been optimized to reduce ambiguity based on feedback from Case Studies. Consistent results from manual assessment and from e-tool assessment 27