Identity, Grouping And Characterisation Of Silver Based Biocidal . - Bund
Identity, grouping and characterisation of silver based biocidal active substances including nano-silver Ulrike Frank Swedish Chemical Agency February 2012 www.kemi.se
Identity, grouping and characterisation of silver based biocidal active substances including nano-silver What are biocides? The evaluation of silver under the biocides legislation Applications of biocidal silver Treated articles and their implications for risk assessment When is nano an issue? www.kemi.se
What are Biocides? www.kemi.se
What are Biocides? www.kemi.se
What are Biocides? Biocides are agents usually meant to kill organisms They must not be sold without pre-marketing approval authorization. Details are regulated in the European Biocides Directive (98/8/EC) respectively in the Biocides Regulation (Reg. EC No xxxx/2012) to be published in summer 2012 www.kemi.se
The evaluation of silver Silver is a potent antimicrobial agent Silver is used as active substance in biocidal products and in treated articles All active substances have to be authorized to be permitted to be placed on the market after May 2014 www.kemi.se
The evaluation of silver KemI (SE) is responsible for the evaluation of silver as an active substance within BPD At the moment: transitional period unregulated market In future: only silver uses which show acceptable risks get authorized www.kemi.se
Silver? www.kemi.se
Silver? Silver containing substance (SCAS) Elemental silver a) Particulate silver b) Silver ionisation systems CAS No. 7440-22-4 7440-22-4 Silver adsorbed to silica dioxide Not yet allocated Silver chloride adsorbed to titan dioxide Not yet allocated Silver nitrate Silver sodium hydrogen zirconium phosphate Silver zinc zeolite Silver copper zeolite Silver phosphate glass Silver borosilicate glass 7761-88-8 265647-11-8 130328-20-0 130328-19-7 308069-39-8 308062-97-7 www.kemi.se
Example: Silver (zinc) zeolite www.kemi.se
Example: Nano-silver composite www.kemi.se
Example: Silver nitrate www.kemi.se
Nano-Silver: Definition Biocides Regulation (from COM recommendation) Art. 3, (z) "nanomaterial" means a natural or manufactured active substance or non-active substance 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 1 nm-100 nm; For the purposes of the definition of nanomaterial, ‘particle’, ‘agglomerate’ and ‘aggregate’ are defined as follows: (a) ‘particle’ means a minute piece of matter with defined physical boundaries; (b) ‘agglomerate’ means a collection of weakly bound particles or aggregates where the resulting external surface area is similar to the sum of the surface areas of the individual components; (c) ‘aggregate’ means a particle comprising of strongly bound or fused particles; www.kemi.se
Nano-Silver: Definition “Nano definition is lawyers' paradise, says expert A member of the UK government's Advisory Committee on Hazardous Substances (ACHS) has described the EU definition of nanomaterials adopted last October as a "lawyers' paradise" that will be difficult for regulators to work with. ” (Source: ENDS, 14th december 2011) www.kemi.se
Nano? Silver containing substance (SCAS) Elemental silver a) Particulate silver b) Silver ionisation systems CAS No. 7440-22-4 7440-22-4 Silver adsorbed to silica dioxide Not yet allocated Silver chloride adsorbed to titan dioxide Not yet allocated Silver nitrate Silver sodium hydrogen zirconium phosphate Silver zinc zeolite Silver copper zeolite Silver phosphate glass Silver borosilicate glass 7761-88-8 265647-11-8 130328-20-0 130328-19-7 308069-39-8 308062-97-7 www.kemi.se
Nano? Silver containing substance (SCAS) Elemental silver a) Particulate silver b) Silver ionisation systems CAS No. 7440-22-4 7440-22-4 Silver adsorbed to silica dioxide Not yet allocated Silver chloride adsorbed to titan dioxide Not yet allocated Silver nitrate Silver sodium hydrogen zirconium phosphate Silver zinc zeolite Silver copper zeolite Silver phosphate glass Silver borosilicate glass 7761-88-8 265647-11-8 130328-20-0 130328-19-7 308069-39-8 308062-97-7 www.kemi.se
Nano? Silver containing substance (SCAS) Elemental silver a) Particulate silver b) Silver ionisation systems CAS No. 7440-22-4 7440-22-4 Silver adsorbed to silica dioxide Not yet allocated Silver chloride adsorbed to titan dioxide Not yet allocated Silver nitrate Silver sodium hydrogen zirconium phosphate Silver zinc zeolite Silver copper zeolite Silver phosphate glass Silver borosilicate glass 7761-88-8 265647-11-8 130328-20-0 130328-19-7 308069-39-8 308062-97-7 www.kemi.se
3- PO4 Silver as antimicrobial agent Ag Ag SH - Ag Antimicrobial effect caused by Ag Ag Ag Ag Diffusion aktiv Ag Ag Ag Silver ion exchangers Notified active substances Silver zirconium phosphat Silver zeolite Silver glass Ag Ag Ag Silver salts Elementary silver Silver composites Silver Silver on SiO2; Silver chloride on TiO2 Silver – chloride -nitrate
Silver as antimicrobial agent Ag release varies over a wide range, dependent on: - Silver releasing agent - pH and ion-content of solvent Nano-silver possibly has a higher release rate per mass of silver due to bigger surface area Silver sulfide low www.kemi.se Silver hydrogen zirconium phosphate Silver zeolite Silver chloride compos ite Elemental silver (mikro) NanoSilver compo site? Ag release in deionized water Silver glass Silver nitrate high
Does size matter? Example water solubility: Particle size Water solubility www.kemi.se Silver powder Nano silver in compound 2-55 µm 22.8 mg Ag/L 5-20 nm 210.3 mg Ag/L
Does size matter? Silver electrode www.kemi.se Powdered silver
Biocidal applications www.kemi.se http://www.zeomic.co.jp/englis h
Biocidal applications Infinite application(possibilitie)s: http://www.alibaba.com/showroom/germ-free-material 3.html http://www.housekeepingchannel.com/tag 238 Antimicrobial http://www.zoflora.co.uk/ Silver: The Silver Nanotechnology Commercial Inventory, Emma Fauss, University of Virginia, September 2008; s/6718/fauss final .pdf products on the market contain real nano-silver, or are named ”nano” because that is catchy www.kemi.se
Applications with antimicrobial Silver Water film Example: Toilet seat Plastic or Coating Ag Bulk Silver Particle 24
Applications with antimicrobial Silver Water film Example: Toilet seat Plastic or Coating Ag Nano Silver Particle 25
Applications with antimicrobial Silver Water film Example: Toilet seat Plastic or Coating Ag Nano Silver Particle 26
Applications with antimicrobial Silver Water film Example: Toilet seat Plastic or Coating Ag Nano Silver Particle 27
How is antimicrobial silver applied? Most variably! Fiber Fiber Active substance Masterbatch Coating www.kemi.se Silver additive Silver additive Treated article
Quantity of silver applications Silver applications Overall distribution (%) www.kemi.se treated article 31 coating textile 49 10 liquid liquid consumer industrial 3 7
Exposure Assessment www.kemi.se
Exposure Assessment www.kemi.se
New in Biocides Regulation Article 4, Conditions for approval . 4. The approval of an active substance shall not cover nanomaterials except where explicitly mentioned. This is a result of EP’s position during first reading: “ .Special attention to nanomaterials Lastly, with doubts remaining over the possible long-term health effects of nanomaterials, MEPs insisted on the need for separate assessment of such particles in biocidal products” (source: EPs website) www.kemi.se
New in Biocides Regulation Treated articles are defined (Art. 3 (l)) Use of a biocidal product includes use in treated articles (Art. 3 (k)) Articles may only be placed on the market in Europe when treated with biocidal products which contain active substances authorized in Europe Treated articles have to be labelled: - if they make a biocidal claim - if they contain nanomaterial - if there is considerable release (decided upon at active substance authorization) www.kemi.se
Conclusions Nano is an issue – amongst others – for the evaluation of silver The original active may be in nano-size the form man and environment are exposed to might be very different The focus on ”Nano” can obscure the issues which deserve even more attention Exposure for different uses and application areas is the biggest challenge in the evaluation of silver www.kemi.se
Conclusions Nano or not nano. Is that a question? No Yes s Ye Yes Yes No No www.kemi.se No No
Applications with antimicrobial Silver Spray applications: ? Probably high exposure during use Different assessment depending on (end-)use? www.kemi.se
Kemis Washing Study Scope: 30 different textiles were purchased and analysed for silver before, after 3 x and after 10 x washing The original content varied to a large extent. Between 0,4- 1360 mg/kg textile In general the original content of silver was between 10-50 mg/kg After 10 washes the samples had leached between 10-98 %. In many cases 80 % Already after 3 washes 10 of the samples leached 43 %
Different Assessment of Different Silver Forms? Silver form Competent Authority Report Inclusion decision Silver zinc zeolite x x Silver copper zeolite x x Silver nitrate x x Silver sodium hydrogen zirconium phosphate x x Silver phosphate glass x x Silver borosilicate glass x x Silver (electrode, powder) x x x Silver chloride on TiO2 x x Silver nano-composite x x
Risk Assessment Risk: Hazard x Exposure Exposure: For every compartment and life stage Model calculations www.kemi.se Hazard: inherent properties of a substance Tox studies with representative organisms
Risk Assessment Chemical properties Effect Exposure Exposure Effect Risk For every compartment/ life stage Exposure Effect acceptable Risk! For every compartment Risk characterisation – compartment, life stage 40
Nano? Silver containing substance (SCAS) CAS No. Elemental silver a) Particulate silver 7440-22-4 b) Silver ionisation systems 7440-22-4 Silver adsorbed to silica dioxide Not yet allocated Silver chloride adsorbed to titan dioxide Not yet allocated Silver nitrate 7761-88-8 Silver sodium hydrogen zirconium phosphate 265647-11-8 Silver zinc .
Grouping & Case II Factoring Factoring by Grouping: A new type of factoring is factoring by grouping. This type of factoring requires us to see structure in expressions. We usually factor by grouping when we have a polynomial that has four or more terms. Example Steps x3 2x2 3x 6 1. _ terms together that have
Not all polynomials can be factored. Just like some numbers areprime, some polynomials are prime. EXAMPLE 6.7 HOW TO FACTOR A POLYNOMIAL BY GROUPING Factor by grouping: xy 3y 2x 6. Solution TRY IT : :6.13 Factor by grouping: xy 8y 3x 24. TRY IT : :6.14 Factor by grouping: ab 7b 8a 56. 570 Chapter 6 Factoring
temperature and reproduce part performance in FE codes, coupling micromechanical characterisation with macroscopic tests. Smart material data characterisation from tests to modelling help to handling material data for part design. Part and Forming Process Design High temperature FLC characterisation Frictionless determination of sheet metal forming
DRAFT - FOR THE BLUE COD MANAGEMENT GROUP ONLY 1 In support of the Marlborough Sounds blue cod regulatory review APPENDIX ONE: BLUE COD FISHERY CHARACTERISATION June 2015. Appendix One: Blue Cod Fishery Characterisation, June 2015 · 2 CONTENTS
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