1、Nanotechnologies Overview of available frameworks for the development of occupational exposure limits and bands for nano-objects and their aggregates and agglomerates (NOAAs) PD ISO/TR 18637:2016 BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06National foreword This
2、 Published Document is the UK implementation of ISO/TR 18637:2016. The UK participation in its preparation was entrusted to Technical Committee NTI/1, Nanotechnologies. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purpor
3、t to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 978 0 580 82428 9 ICS 07.120 Compliance with a British Standard cannot confer immunity from legal obligatio
4、ns. This Published Document was published under the authority of the Standards Policy and Strategy Committee on 31 December 2016. Amendments/corrigenda issued since publication Date Text affected PUBLISHED DOCUMENT PD ISO/TR 18637:2016 ISO 2016 Nanotechnologies Overview of available frameworks for t
5、he development of occupational exposure limits and bands for nano- objects and their aggregates and agglomerates (NOAAs) Nanotechnologies Vue densemble des cadres disponibles pour la dfinition de limites et bandes dexposition professionnelle applicables aux nano-objets, leurs agrgats et agglomrats (
6、NOAA) TECHNICAL REPORT ISO/TR 18637 Reference number ISO/TR 18637:2016(E) First edition 2016-12-01 PD ISO/TR 18637:2016 ISO/TR 18637:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this
7、 publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the
8、 country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.org PD ISO/TR 18637:2016 ISO/TR 18637:2016(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms an
9、d definitions . 1 4 Symbols and abbreviated terms . 3 5 Description of available processes for setting OELs and OEBs . 5 5.1 General considerations 5 5.2 Description of evidence-based process . 6 5.3 Substance-specific OELs . 8 5.4 Categorical OELs 8 5.5 Initial or default occupational exposure band
10、s 9 6 Substanc e-specific OELs for nanomat erials 10 6.1 General overview .10 6.2 Available substance-specific OELs 10 6.2.1 Carbon nanotubes 10 6.2.2 Nanoscale TiO 211 6.2.3 Fullerenes 12 6.3 Evaluation of OEL methods .12 6.3.1 Similarities and differences .12 6.3.2 Influence of methods on derived
11、OEL values for nanomaterials 13 6.3.3 State of the science in support of risk assessment methods for nanomaterials OELs .14 7 Categorical OELs for nanomaterials 15 7.1 Summary of options proposed .15 7.1.1 United Kingdom .15 7.1.2 Germany .15 7.1.3 NIOSH .17 7.1.4 Japans (AISTs) approaches 17 7.1.5
12、OECD 18 7.2 Evaluation of categorical OEL .19 7.2.1 Similarities and differences .19 7.2.2 State of the science supporting categorical OELs .20 8 OEBs and control banding for nanomaterials .21 8.1 Overview of current hazard and control banding schemes 21 8.1.1 Comparison of hazard bands and OEBs as
13、applied to inhaled NOAAs .22 8.1.2 ISO hazard banding scheme for NOAAs 25 8.2 Case studies on banding NOAAs .26 8.3 Evaluation of the evidence for initial (default) OEBs for categories of NOAAs 28 8.3.1 Categorical analyses and read-across .28 8.3.2 Utility of in vitro data in OEL/OEB development fo
14、r NOAAs .29 8.3.3 Options for deriving an OEL or OEB for NOAAs .30 9 Feasibility considerations in the OEL and OEB setting process 30 Annex A (informative) Standard processes for OEL setting 32 Bibliography .62 ISO 2016 All rights reserved iii Contents Page PD ISO/TR 18637:2016 ISO/TR 18637:2016(E)
15、Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a t
16、echnical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters
17、 of electrotechnical standardization. The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of ISO documents should be noted. This docu
18、ment was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all s
19、uch patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents). Any trade name used in this document is information given for the convenience of users and d
20、oes not constitute an endorsement. For an explanation on the meaning of ISO specific terms and expressions related to conformit y assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: w
21、ww.iso.org/iso/foreword.html. The committee responsible for this document is ISO/TC 229, Nanotechnologies.iv ISO 2016 All rights reserved PD ISO/TR 18637:2016 ISO/TR 18637:2016(E) Introduction Nano-objects and their aggregates and agglomerates (NOA As) represent a subset of particulate materials tha
22、t can be dispersed in the air and can represent health risks via inhalation exposures. NOAAs include structures with one, two or three external dimensions in the nanoscale from approximately 1 nm to 100 nm, which may be spheres, fibres, tubes and others as primary structures. NOAAs can consist of in
23、dividual primary structures in the nanoscale and aggregated or agglomerated structures, including those with sizes larger than 100 nm. An aggregate comprises strongly bonded or fused particles (structures). An agglomerate is a collection of weakly bound particles (structures) 1234 . The purpose of t
24、his document is to describe a general framework for the development of occupational exposure limits (OELs) or occupational exposure bands (OEBs) for individual NOAAs or categories of NOAAs with different levels of available data. OELs and OEBs are important tools in the prevention of occupational il
25、lness. OELs have a long history in industrial hygiene and are based on observations of workers or studies of laboratory animals. OELs are established to minimize the likelihood of adverse effects from exposure to potentially hazardous substances in the workplace 56 . An OEL is generally substance-sp
26、ecific (although sometimes generically expressed, such as dust). Sufficient data to develop an OEL may not be available, especially for substances such as NOAAs used in emerging technologies. To aid in hazard communication and exposure control decisions for substances without OELs, hazard banding ha
27、s been used for many years 789 . Substances are assigned to a hazard band based on limited toxicity data usually from animal studies. Hazard banding schemes typically consist of qualitative bands ranging from low to high severity of effects. Thus, a hazard band represents a range of potential toxici
28、ties for a particular substance or category of substances. Some hazard banding schemes include associated OEBs 10 . The term OEB is a general term for exposure concentration ranges used in some hazard banding schemes that are related to the ranges of hazard potentials. In contrast to an OEB, an expo
29、sure band is a range of potential concentrations of a substance (or category of substances) to which workers may be exposed in a defined occupational scenario and which is based on factors such as the amount of NOAA processed or used, the nature of the process, and the form of the NOAA including dus
30、tiness 3 . In control banding, the hazard band and the exposure band are combined to determine the control band for any particular occupational scenario (e.g. ISO/TS 12901-2). OELs and OEBs are part of an overall occupational safety and health (OSH) program and are not intended to identify and addre
31、ss all safety and health risks associated with a specific process or task. OELs and OEBs are intended to provide occupational safety and health professionals with a health basis for assessing the effectiveness of exposure controls and other risk management practices. The exposure assessment of nanom
32、aterials including carbon nanomaterials such as fullerene, graphene, single-walled carbon nanotube (SWCNTs) and multi-walled carbon nanotube (MWCNTs), metal oxides (TiO 2 , SiO 2 , zinc oxide, iron oxide), and metals (silver and gold nanoparticles) remains a challenge in the field of occupational hy
33、giene, as there have been relatively few studies on the characterization of workplace exposures to NOAA. Sampling and analytical methods that have the capabilities to accurately measure nanomaterials are still under development. Most sampling devices that measure airborne particle count concentratio
34、ns, such as condensation particle counters and optical particle counters, cannot differentiate ambient exposures to background nanoparticles from NOAA in the workplace environment. Airborne measurements of carbon nanotubes (CNTs) and carbon nanofibres (CNFs) using mobility particle sizers also somet
35、imes could present a unique challenge due to the arcing caused by the charged airborne CNT and CNF agglomerates in the differential mobility analyser 11 . Although several groups have attempted to measure and count CNT structures using transmission electron microscopy or other microscopic methods 12
36、13 , there are still no standard methods for measuring and counting CNT structures. In addition, determining the mass concentration of CNTs and CNFs based on measuring the elemental carbon (EC) remains a challenge due to other sources of elemental carbon in the workplace, such as organic composite m
37、aterials and air and diesel pollution that could interfere in the determination of CNT and CNF exposures. Scientific and technical methodologies used to set exposure limits may differ from one entity to another, which can lead to disparities in worker protection from country to country 14 . Therefor
38、e, harmonizing the scientific methodologies used in developing OELs, including using the best available evidence for interspecies extrapolation and specifying the type of data and uncertainties involved in the OEL determination is necessary for a robust health and safety evaluation framework for NOA
39、As. ISO 2016 All rights reserved v PD ISO/TR 18637:2016 ISO/TR 18637:2016(E) This document provides a collaborative, science-based platform to describe and evaluate the state-of- the-art in such data and methods. Current risk assessment methods are likely to apply to NOAAs 15 , although the limited
40、health hazard data for many NOAAs and the considerable variety in the types of manufactured NOAAs present a challenge to the efficient development of OELs for individual NOAAs. To date, few OELs and OEBs have been developed for specific NOAAs and none have been formally regulated by a government age
41、ncy. Standard OEL and OEB methodologies for NOAAs are needed to evaluate the evidence on the hazard potential of NOAAs in the workplace to provide a health basis for risk management decisions, including selection and evaluation of engineering control options. One of the goals of this document is to
42、identify both the similarities and differences in the methods used to develop OELs. This evaluation may lead to improvements in methods for setting exposure limits or bands. This document presents an overview of the state-of-the-art in the development of OELs and OEBs for NOAAs. Current approaches f
43、or assigning default hazard bands in the absence of NOAA-specific toxicity data are described. These approaches build on current hazard and control banding strategies, such as those developed in ISO/TS 12901-2. The current state of the methods and data to develop OELs and OEBs for NOAAs is described
44、 in this document, along with an evaluation of those methods used in developing the current OELs for NOAAs. Categorical approaches to derive OEBs for NOAAs with limited data are also discussed, such as those based on biological mode-of-action (MOA) and physico-chemical (PC) properties. The basis for
45、 the framework described in this document is the U.S. NIOSH Current Intelligence Bulletin Approaches to Developing Occupational Exposure Limits or Bands for Engineered Nanomaterials 16 . This document also takes into consideration other state-of-the-science reports, including outputs of the workshop
46、 “Strategies for Setting Occupational Exposure Limits for Engineered Nanomaterials,” which was held on September 10-11, 2012 in Washington, DC, USA 6and the OECD Working Party on Manufactured Nanomaterials Expert Meeting on Categorization of Manufactured Nanomaterials, September 17-19, 2014 17 . The
47、 primary target audience of this document is occupational safety and health professionals in government, industry, and academia, who have the expertise to develop OELs or OEBs based on the guidance in this document. In addition, the evidence-based approach described in this document may be useful in
48、 the evaluation and/or verification of current hazard and control banding schemes and for identifying the key data gaps. Control banding requires information on both the applicable hazard category and exposure category. Appropriately verified control banding tools would be broadly useful, as these t
49、ools require less specialized expertise and resources (than for a comprehensive risk assessment) and are accessible to a wider group of individuals and small businesses. Therefore, this document can be considered complementary to ISO/TS 12901-2 on control banding for nanomaterials as it describes the state-of-the-art in the process of assigning nanomaterials to hazard bands/OEBs when the scientific evidence is not sufficient to develop an individual OEL. Some of the cited methods lead to results that are not
