Blootstelling aan nano op de werkplek: een werkelijk gevaar? Josje Arts AkzoNobel PS&RA

Transcription

1 Blootstelling aan nano op de werkplek: een werkelijk gevaar? Josje Arts AkzoNobel PS&RA

2 Definition of nanomaterial EU definition: "Nanomaterial" means a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range nm Issues: natural/incidental aggregate/agglomerate Aggregate: strongly (covalently) bonded or fused primary particles Agglomerate: weak interaction (van der Waals interactions, hydrogen binding, physical adhesion) 2

3 Nanomaterials examples Examples of natural/incidental nano Anthropogenic sources: Traffic exhaust Process generated (PGNP) By electrical machines Heating Welding Combustion processes Examples of engineered/manufactured nano (MNM) Nanoparticle Nanoplate Nanofibre * nanowire * nanorod * nanotube -SWCNT - MWCNT 3

4 Examples of nanomaterials 4

5 Guidances for working with nano FNV/VNO/NCW/CNV Working safely with engineered nanomaterials and nanoproducts A guide for employers and employees Version 4.2- August 2012 RPA Guidance on the protection of the health and safety of workers from the potential risks related to nanomaterials at work (commissioned by the European Union Programme for Employment and Social Solidarity PROGRESS ( ) Risk & Policy Analysts Ltd, UK; IVAM Research and Consultancy on Sustainability, UvA Amsterdam; Denehurst Chemical Safety Ltd, UK COM 2.4 June

6 Nanomaterials classification proposals FNV/VNO/NCW/CNV Rigid, biopersistent nanofibres for which effects similar to those of asbestos cannot be excluded Examples: SWCNT or MWCNT or metal oxide fibres for which asbestos-like effects are not excluded Biopersistent granular nanomaterial (non-fibrous), with a density >6,000 kg/m3 Examples: particles like Ag, Au, CeO2, CoO, Fe, FexOy, Pb, Sb2O5, or SnO2 Biopersistent granular nanomaterials and nanofibres for which asbestos-like effects can be excluded, with a density <6,000 kg/m3 Examples: particles like Al2O3, SiO2, TiO2, ZnO, CaCO3, nanoclay, carbon black, C60, dendrimers, polystyrene or nanofibres without asbestos-like effects Non-biopersistent granular or (water) soluble nanomaterial (solubility > 100 mg/l) Examples: NaCl-, lipid-,flour-, sucrose particles RPA Poorly soluble/insoluble (water solubility <100 mg/l) WHO nanofibres Examples: fibres with a length more than 5 um, rigid & fluffy nanofibres (might get tangled and become rigid), some types of CNT Poorly soluble/insoluble (water solubility <100 mg/l) nanoparticles with specific toxicity and poorly soluble/insoluble HARNs other than poorly soluble/insoluble WHO nanofibres Examples: nanofibres < 5 um, nanoplatelets, Ag, Au, ZnO Poorly soluble/insoluble nanomaterials with no specific toxicity Examples: carbon black, TiO2 Soluble nanomaterials Examples: NaCl-, lipid, flour-, sucrose particles and amorphous silica 6

7 Suggested OELs (March 2013) MWCNT (Baytubes) MWCNT (Nanocyl) REL (ug/m3) DNEL (ug/m3) Reference 8-h TWA 50 Pauluhn (2009) 8-h TWA 2.5 Nanocyl (2009) CNT and CNF 8-h TWA 1 NIOSH (2013) MWCNT Fullerenes Chronic inhalation Chronic inhalation Stone et al (2009) 270 Stone et al (2009) Ag (18-19 nm) DNEL 98 Stone et al (2009) TiO2 ( nm) 10 h/day, 40 h/wk 300 NIOSH (2011) Note: the OEL for micro-sized TiO2 is 2400 ug/m3 7

8 Nano Reference Values (NRV) in NL Description Density (kg/m3) NRV (8-h TWA) Examples Rigid, biopersistent nanofibres for which effects similar to those of asbestos are not excluded 0.01 fibres/ cm3 SWCNT or MWCNT or metal oxide fibres for which asbestoslike effects are not excluded Biopersistent granular nanomaterial in the range of nm Biopersistent granular and fibre form nanomaterials in the range of nm Non-biopersistent granular nanomaterial in the range of nm >6,000 20,000 particles/ cm3 <6,000 40,000 particles/ cm3 Applicable OEL Ag, Au, CeO2, CoO, Fe, FexOy, Pb, Sb2O5, or SnO2 Al2O3, SiO2, TiO2, ZnO, CaCO3, nanoclay, carbon black, C60 dendrimers, polystyrene or nanofibres without asbestos-like effects NaCl-, lipid-,flour-, sucrose particles 8

9 Nanomaterials possibility of exposure FNV/VNO/NCW/CNV Emission of (primary) MNM is possible RPA (Risk & Policy Analyses) Emission of MNM likely due to free/unbound state, high dustiness & volatility Emission of MNM embedded in a larger solid (>100 nm) or liquid matrix is possible Emission of MNM possible due to medium dustiness & volatility Emission of MNM anticipated as very low due to low dustiness & volatility Emission of MNM minimised due to working in full containment Unlikely emission of MNM 9

10 Nanomaterials control banding FNV/VNO/NCW/CNV Hazard 1 Hazard 2 Hazard 3 Exposure I A A C Exposure II A B C Exposure III B C C RPA Exposure Hazard High Medium high Medium low High Medium high Medium low Low Low 10

11 Control banding advised control FNV/VNO/NCW/CNV Control level A B C Advised control Hierarchic OHS strictly applied (source reduction, technical measures, organisational measures, PPE) According to OHS technical and organisational measures are evaluated for economic feasibility, control measures to be decided Sufficient (room) ventilation, LEV and/or containment of the source if needed, use appropriate PPE RPA Control level Advised control 1 (1) Investigate substitution, (2) modify process or consider containment, (3) engineering and administrative control measures, PPE 2 Engineering and administrative control measures, PPE 3 Engineering control measures such as local extraction 4 General ventilation 11

12 Risk assessment & management (RPA) 12

13 Question: how to differentiate between PGNPs and MNPs at the workplace? Available: manual equipment for simultaneously measuring number concentration and diameter Measuring strategy: 1. Measure background particle number concentration (natural/anthropogenic) 2. Measure particle number concentration generated by processing equipment without use of MNP or nanoproducts 3. Measure total particle number concentration during processing including use of MNP 4. Subtract (1) and (2) from (3) 5. Calculate 8-h TWA Problem: it is quite likely that airborne MNPs will agglomerate with PGNPs 13

14 Material properties Life cycle use and release waste production processing use Exposure route and dose? adverse health effect

15 Issues/remarks 1. Nanoparticles (real nano!) are only present in the production phase; powders consist of aggregates/agglomerates. As such they have already been tested and evaluated (TiO2, carbon black, amorphous silica) 2. It is a real challenge to generate and maintain nano-sized particles in air (coagulation takes place in milliseconds). The only methods available are: spark technique or electro-spray technique. Also then the distance between generation and exposure had to be very short and/or inert gases needed to be used 3. Some aggregates/agglomerates may partly deagglomerate/deaggregate in lung fluid but this is very difficult to achieve. Nebulizing such solutions (which had a primary nano-size) did not result in nano-sized particles in air 4. In specialized studies in which real nano-sized particles were generated it was shown that 20% of the particles were taken up by macrophages (which were most close); in contrast, 80% of the aggregates/agglomerates were engulfed 5. Biokinetics may be helpful in establishing absorption to assess accumulation in the body after dermal or oral exposure 6. There is no need for additional evaluation of inhalation of nano-sized particles in case of existence as aggregates/agglomerates; there is more need for nanotubes and especially nanofibres 15

16 Thanks for your attention! Questions? 16