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Nanomaterials and workplace health & safety What are the issues for workers? Aída Maria Ponce Del Castillo Researcher, European Trade Union Institute - PDF
Nanomaterials and workplace health & safety What are the issues for workers? Aída Maria Ponce Del Castillo Researcher, European Trade Union Institute
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1 Nanomaterials and workplace health & safety What are the issues for workers? Aída Maria Ponce Del Castillo Researcher, European Trade Union Institute
2 European Trade Union Institute, 2013 ISBN
3 Contents 05 Preface 07 Part 1 Why does it matter to workers? 08 Nanomaterials 11 Nanoproducts and applications in the market 13 Common examples of nanomaterials at the workplace 16 Routes of human exposure to nanoparticles 19 Part 2 Working with nanoparticles 19 How can workers identify nanomaterials? 20 What activities involve working with nanomaterials? 21 What type of health and safety information do workers need to know? 27 Safety control tools at the workplace 29 Part 3 Health surveillance during and after exposure 33 Part 4 Exposure registries as tools for medical surveillance 35 Register who? Doing what? Identifying workers and their activities 39 Conclusion 41 Bibliographical references
5 05 Preface Nanotechnologies have been variously seen as the great white hope of the 21 st century economy. It is an agenda made up of the heady brew of research and knowledge, the dread of what human enhancement may hold, the cold language of the moneymen and the belief that a faster use of what the infinitely small has to offer could deliver environmentally-neutral growth. Although invisible to the naked eye, nanomaterials are produced and used in real-life workplaces. The industries concerned are not the stuff of sci-fi, and the unquestionable beauty of the images yielded by electron microscopy reflect nothing of a work organization far removed from the clean-room lab environment. Nano materials are found in industries where risks abound, preventive measures are often disregarded and workers have little control over their working conditions. This is largely glossed over by the scientific literature and public debate. There is nothing new there. In the late 19 th century, asbestos was described as the magic fibre for being a cheap raw material in plentiful supply and adaptable to many uses. Even early warning signals of a looming health disaster failed to stem its unhindered massive spread throughout the first three quarters of the 20th century. An indiscriminate use that would cause millions of preventable deaths. So that nanotechnologies do not become the new asbestos, the European Trade Union Institute has been putting out information on them over the years. This booklet on the working conditions involved in the production and use of nanomaterials is a new addition. There is no scaremongering here, but the sobering observation that nanomaterials are coming onto the market in a widening range of uses at a dizzying pace, but the impact on society is going largely undiscussed. Occupational health is a specific aspect of that impact. The current data are scant and very patchy. The research that is sounding alarm bells about the toxicity of some nanomaterials should be prompting all stakeholders to implement the precautionary principle without more ado. Current EU law does not address the specific properties of nanomaterials. Workers and consumers health will go unprotected unless EU law is adapted to
6 06 take into account the specific requirements of these new risk factors. And that means production and marketing rules as much as the Directives on the protection of workers health. This book sets out to do three things: give a better understanding of how nanomaterials impact on workers health; identify improvements needed to the legislative framework; and suggest practical ways for trade unions and occupational health professionals to ensure better prevention right now and implement the necessary health surveillance for exposed workers. Laurent Vogel ETUI
7 Part 1 Why does it matter to workers? 07 When we talk about nanotechnologies, we are really talking about diverse technology platforms applied across many sectors and industries. Nanotechnology is all about manipulating matter at nanometric levels a nanometre is one billionth part of a metre enabling materials and structures to be created with properties very different from larger structures with the same composition. Working with such materials on a scale smaller than the human eye can see brings hazards and risks that may not be fully identified and yet there is no consensus on techniques for measuring nanoparticles in the workplace. But health and safety programmes need to be fully developed and implemented. The market in products incorporating nanotechnologies stood at 200 billion dollars worldwide in 2008 and is constantly expanding as more products and more nano-enabled technologies come onto it applications promising to help improve access to water, medicine, energy efficiency, and more. All in all, nanotechnology promises huge life-enhancing potential, but it would be a tragedy were the health of workers, who are in the front line, to pay the price for it. Nanotechnology is a big issue for the European labour market because of its cross-sectoral penetration of traditional and emerging industries. The nanotech revolution is driving the emergence of new businesses, spin-off companies and small and medium-sized firms, and impacting on working conditions. Workers have been dealing with nanomaterials in sectors like construction, chemicals, electronics, car making, energy, etc. as they work with new materials, applications, machinery, industrial processes and products. Products are being brought to market with too little scrutiny by the authorities who therefore have little idea of what is being marketed. Working with nanotechnologies brings unknowns for health and safety into the workplace, so extreme precaution is required in working conditions. The effects
8 08 on human health and the environment could be disastrous think only of asbestos and other ultrafine particles in the past. Recent surveys (Conti 2008, INRS 2010b, Engeman 2012) in the United States and France reveal that companies are unsure about how best go about protecting health and safety or what to do in case of contamination. Worryingly, they report that the number of workers potentially exposed to nanoparticles is not known. If companies are having difficulties getting to grips with health and safety and their programmes do not include specific practices, workers are at even greater risk. Employees have no idea whether they are handling nanomaterials or what if any risks may be involved, and even highly qualified laboratory staff may be uncertain about how safe materials are to handle. This publication aims to raise awareness among all those involved with nanotechnology at any stage of in manufacture and production, right up to waste disposal. It tries to bring answers to key questions such as: What are nanomaterials? Where can they be found? How can workers be exposed? What is the essential information they need to know? How important is health surveillance? It also looks at some regulatory action taken by the European Union to provide a framework to the debate. Nanomaterials The key characteristic of a nanomaterial is that it presents properties that would not be found in the same materials at its normal scale. The International Organization for Standardization (ISO) defines a nanomaterial as a material with any external dimension in the nanoscale or having internal or surface structure in the nanoscale. The nanoscale is the size range from approximately 1 to 100nm, where an nm (nanometre) is a billionth of a metre, or in scientific terms, about 10 to the power of -9. The ISO classifies nanomaterials into 2 categories: nano-objects and nano-structured materials. Nano-objects are materials with any external dimension in the nanoscale. A nano-structured material is a material with internal or surface structure in the nanoscale. Nano-objects are nanoparticles, which have 3 external dimensions at the nanoscale; nanofibres with 2 external dimensions at the nanoscale and nanoplates with only one external dimension at the nanoscale. The problem with a technical definition is that it cannot be applied to all regulations that deal with nanotechnology. This is why the debate on a regulatory definition of what constitutes a nanomaterial has been exercising the minds of scientists, manufacturers, policy makers, Member States and different stakeholders in Europe since A crucial part of the process was to have a science-based definition that could be accommodated within the legal system. Where nanotechnology is concerned, reliance on the current scientific data would have been on shifting sands because the science is not yet settled; knowledge is constantly emerging in those areas of nanotechnology that are yet uncharted territory. A regulatory definition cannot just be science-based because other factors are also in play; ethical, political and societal aspects have to be factored in to facilitate governance. After a series of debates, analyses of scientific opinions submitted by the European Commission s Joint Research Center (JRC) and the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR), the European Commission put a draft definition out to public consultation in late With the scientific opinions and consultation outcomes, the Commission was finally able to issue a recommendation on 18 October 2011 on an EU definition of the term nanomaterial to be applied by the European agencies, the Member States and companies operating in the EU.
9 09 Figure 1 The nanoscale Sugar cube Diameter 10 mm Grain of sand Diameter 1 mm nm (100 mm) nm (10 mm) nm (1 mm) One nanometre (nm) is equal to one-billionth (1,000,000,000) of a metre, 10-9 m. Most structures of nanomaterials which are of interest are between 1 and 100 nm in one or more dimensions nm (0.1 mm) (100 µm) nm (0.01 mm) (10 µm) Typical bacterium Diameter nm nm (1 µm) Typical virus Diameter 100 nm 100 nm (0.1 µm) Carbon nanotubes Diameter 10 nm 10 nm (0.01 µm) DNA strand Diameter 1 nm 1 nm (0.001 µm) 0.1 nm ( µm) Source: Novel Materials in the Environment: The case of Nanotechnology, Royal Commission on Environmental Pollution, November 2008 The Commission s development of a benchmark definition for EU policy was mainly prompted by the European Parliament s call in its Resolution of 24 April 2009, coupled with the inclusion of specific provisions on nanomaterials in different pieces of legislation, like the requirements in the EU Regulation on cosmetic products (EC No. 1223/2009), and the fact that other non-identical definitions of nanomaterials were to be found. The EC Recommendation on the definition has no regulatory impact as is. To have any legislative effect it must be properly implemented in the relevant regulations. So far, it is already referenced in the EU Biocides and Ecolabel Directives. When used in biocides, nanomaterials will need a separate assessment; products containing nanomaterials will have to be clearly labelled, along with the specific risks of making available on the market. The core terms of the definition are laid down in three different paragraphs. The first paragraph the most technical part refers to size rather than mass, reflecting assumptions about the risk of small particles. The definition specifies that the size rather than the mass of a particle is what determines what a nanomaterial is. According to the definition, a nanomaterial is 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
10 10 the particles in the number size distribution, one or more external dimensions is in the size range 1 nm nm. It is the particle itself that is important: it may be unbound, aggregates or agglomerates, but 50% or more of the particles must be in the size distribution between 1 and 100 nm for the primary article to meet the definition. The 50% value was chosen over the 1% recommended by the SCENIHR scientists because a lower value would have brought too many materials within the scope of the definition. The definition does not mean that all nanomaterials will be subject to the specific requirements incidental nanoparticles 1, like those in volcano ashes or produced during milk homogenization, will escape it. And it does not supporting definitions of other term like particles, agglomerates and aggregates. The second part of the recommendation is an exception that allows for a lower percentage. It says that where there are specific environmental, health, safety or competitiveness concerns, paragraph 1 may not apply and the number size can be between 1 and 50 percent. The third and final part specifically says that fullerenes, graphene flakes and single wall carbon nanotubes are considered as nanomaterials, whether or not they are unbound or agglomerates. The Commission set out to create a uniform definition, but the substantive debate was challenging in that different exposure risks had to be taken into account. Now that the definition has been published, the task ahead will be to update the accompanying Questions and Answers document. Assuming that the Commission s definition will be reviewed in 2014, care must be taken in using the Recommendation and appropriate guidance needs developing for its full implementation in REACH and other regulations. Even though REACH the comprehensive regulation on chemical substances was not designed to cover nanomaterials, the European Commission says that in principle it also applies to nanomaterials, notwithstanding that some gaps are currently under discussion, like the threshold for registration of chemical substances manufactured or imported in quantities less than 1 tonne per year, to which REACH does not apply. Figure 2 Counting nanoparticles 1 nm 100 nm > 100 nm Source: Author 1. Incidental nanoparticles are created during processes such as combustion and food milling, churning, freezing, and homogenization.
11 11 Nanoproducts and applications in the market Materials at the nanoscale present completely different properties to those at the macroscale. This will undoubtedly put them at the centre of the next industrial revolution. Incidental nanomaterials exist in nature sea breeze and volcanic ash are just two of many. This chapter will look at nanomaterials that are manufactured generally in dry and soluble forms to have specific properties or a specific composition for commercial purposes. Table 1 Selection of global market forecast for nanotech- products, billion USD LuxResearch (2006, 2008) Business Communication Company (2008) Cientifica (2008) RNCOS Industry Research Solutions (2006) Wintergreen Research (2004) 750 Evolution Capital (2001) National Science Foundation (2001) Source: Modified from Palmberg 2009 A 2010 report from the Organization for Economic Co-operation and Development (Palmberg 2009) details the investment trends and potential economic impacts of nanotechnologies. Its forecasts look at the full range of products along the value chain that are believed to be affected by nanotechnology. It foresees a host of products and applications, some possibly replacing or enhancing existing products, others completely new. The OECD suggests that even though these forecasts should be treated with caution, it is clear that nanotechnology is likely to have a big economic impact in the long term. Too little can be found out about nanomaterial-containing products on the market; all that is available are figures from databases yielded by internet searches. According to a variety of internet databases like the Project on Emerging Technologies (PEN, or Nanowerk (www.nanowerk.com), nanotechnology-based products can be found in a wide range of sectors like the car making industry, space and aviation; electronics and communications, chemicals and novel materials; pharmaceuticals and medicine; cosmetics and healthcare and in energy technologies. The EU is investing 488 million euros in nanotechnology, concentrated in areas like factories of the future, green cars and energy-efficient buildings 2. Where the safety of these products is concerned, the European Parliament s 2009 Resolution claimed that there was a lack of information about the safety of nanomaterials already on the market. To get a better picture, Parliament asked the Commission to develop a public inventory of the different types and uses of nanomaterials on the market, respecting justified commercial secrets. While the discussions on the EU-wide inventory have been slow moving and the enforcement process can take years while the products are being freely marketed internationally some governments are pre-empting the European Commission by looking into the scope for developing national schemes for companies to report the use of nanomaterials in their products that would help authorities for better traceability. Moves towards developing such a national registry and making it compulsory are currently 2. Funding boost of EUR 7 billion for Innovation Union. European Commission, Community Research and Development Information Service (CORDIS). See
12 12 being taken by an informal coalition coordinated by the competent national authorities in Belgium, France, Italy, the Netherlands and Denmark. France has taken the lead in Europe on tracing nanomaterials and nano-products by introducing regulations making it mandatory for manufacturers, national importers and distributors of nanomaterials in France to make an annual declaration of substances with nanoparticle status. Declarants must give information on the identity of the substance, quantities, uses and the identity of professional users. However, in October 2012 the European Commission published its Communication on the Second Regulatory Review on Nanomaterials accompanied by a Commission Staff Working Paper on the types and uses of nanomaterials, including safety aspects. In this, the Commission argues that the currently available information generated by existing legislative tools like REACH constitute a good basis, so dismissing the idea of an EU-wide inventory called for by Member States. National initiatives on nano-registries in Europe Germany may have a statutory register of nano-products Nano-registry for a green transition in Denmark An agreement between the Danish government and the Red-Green Alliance (Enhedslisten) to strengthen efforts on nanomaterials resulted in September 2012 in the publication of a draft amendment to the Danish Chemicals Act to create a national mandatory database of nanomaterial-containing products. The rules would require producers and importers to report to the government products or mixtures that contain or release nanomaterials. The Danish Environmental Protection Agency will develop the database. The information collected will be used to assess whether the nanomaterial content of products on the Danish market poses a risk for consumers and the environment. The next step would be the enactment of a Ministerial Order containing the detailed rules, expected in The Ministry expects the first product reports to be available in early Working to the precautionary principle of preventing hazards to the environment and to human health including in the workplace, German public authorities aim to authorize a product register covering as many as possible of the nanomaterials produced or placed on the market in Germany. The information gathered should help authorities to identify the manufacturers, producers, importers or distributors of the product. They would have to report: The first manufacture, import or placing on the market of nanomaterials alone or in a mixture; and The first manufacture, placing on the market or import of semi-finished and finished products containing nanomaterials. This would make it easier to keep track of the production, use and disposal of registered nanomaterials and products, and would also be helpful in estimating and assessing the potential contamination pathways for the environment and workers. The OECD s Working Party on Manufactured Nanomaterials (WPMN) is conducting the Sponsorship Programme on the testing of key manufactured nanomaterials to understand their intrinsic properties, toxicity and eco-toxicity that may be relevant for exposure and effects assessments. While this exercise may not produce conclusive results, it could serve as a baseline for more specific research on other nanomaterials and their characteristics and possible toxicity. Nanomaterials that pose certain risks for manufacturing and production workers include carbon nanotubes, silicon dioxide, titanium dioxide and carbon black, and these will be part of the Commission s inventory to be delivered in 2012.
13 13 Table 2 Nano-products and applications by sector Automotive Space Biomedicine, pharmaceuticals Chemistry and materials Cosmetics and Personal care Defence Electronic and communications Energy Environment Food Sports Source: Author Painting and coatings for cars and aeroplanes; reinforced car parts, fuel additives, batteries, durable and recyclable tyres Radiation-tolerant electronics Integrated nanosensor systems Optical sensors Nanomaterials for drug delivery; remote laser light-induced opening of microcapsules Coating of hospital textiles, masks, surgical gowns, catheters; wound dressings; molecular imaging Additive in polymerizable dental materials, additive in bone cement; SiO2 nano-composite resin filler. Coating of implant for joint replacement Pigments, self-cleaning anti-scratch coatings, ceramic powders, corrosion inhibitors, anti-bacterial surfaces and textiles, thermal insulation, inks Sunscreens; facial moisturizers; toothpastes, lipsticks, acne treatments, baby care products Shampoo, conditioner, hair driers, hair irons Battle suits for soldiers; health surveillance system and health healing Molecular electronics and photonics Computer hardware, memories and information high density storage, multifunctional catalysts, micro-chips, sensors, flat screens, carbon nanotube transistors, light-weight display panels, corrosion inhibitors Nanorobots, automatic operations at the nanoscale Nanotube-based transparent conductive film for e-paper Photovoltaic cells, batteries, insulating materials Storage of hydrogen in graphene Climate modelling Pesticides and fertilizers Water treatment and filters Catalysts for better air quality Plastic packaging to block UV rays and provide anti-bacterial protection Bottles, cartons and films containing clay nanocomposite that act as a barrier to the passage of gasses or odours Nanosensors are being developed that can detect bacteria and other contaminants like salmonella at a packaging plant Sports textiles Coating for boats and kayaks Fishing rods made with epoxy resin Tennis rackets, golf clubs, baseball bats, ski equipment, bicycle frames and components Common examples of nanomaterials at the workplace Silicon dioxide, SiO2 Nanomaterials like silicon dioxide or silica are produced in high volumes and are extensively used in a variety of applications and products. Silica in bulk form has been widely used as a food additive for many years to clarify beverages, control viscosity and as an antifoaming agent and dough modifier. Silica can be also found in the nano form in some food products as an anti-caking agent (to prevent the formation of lumps), in the construction industry in high-performance concrete mixtures to increase concrete cohesion and reduce the tendency to particle segregation; and in paints and coatings. Nanosilica is being developed for biomedical applications such as cancer therapy, and drug delivery and in health care products.
14 14 Hydrophobic surfaces incorporating nano-silica. In nature, water is repelled by the rough surface of lotus leaves. The Lotus-effect has been patented by German scientist Dr Wilhelm Barthlott and refers to the idea of constructing surfaces with microscopic raised areas to make them self-cleaning; as a result, dirt and liquids cannot get into the surface and are repelled. Paints and coatings can incorporate silica particles making surfaces self-clean, anti-dirt, anti-graffiti or anti-fingerprint, with high durability. The same water-repellent, stay-clean property can be found in textiles, where fibres treated with the coating work in the same way to repel wet and dirt from the fabric. Nano-silver Different silver compounds are known to have been used for many years: colloidal silver, for example, has been widely used for medicinal and hygienic purposes to treat bacterial infections (Nowack 2011). Silver in the nano form is being manufactured and used in different products and applications to enhance efficiency. Nano-silver inhibits multiplication and growth of bacteria and fungi which cause infection, odour, itchiness and sores, and therefore has been used as an antibacterial, antifungal, anti-viral and anti-inflammatory agent. But it presents different toxicity to its bulk counterpart. Nano-silver is currently found in different products: as a lining in plastic food containers, in underwear, sportswear or socks to kill bacteria, in toothbrushes, surface cleaners, lotions, toys; household appliances like dishwashers, vacuum cleaners and refrigerators. In electronics, nano-silver is mainly used in solder for circuit connections, while silver nanowires are used as nanoconnectors and nanoelectrodes for nanoelectronic devices. It also has medical uses in wound dressings, medical textiles and sterilization materials. Also, at the nanoscale, silver has unique optical and physical properties of potential value in medical diagnostics, drug delivery and imaging. Industry advocates in the United States argue that nanoscale silver has been widely used in the market for at least 12 decades as colloidal nano-silver algaecides and composite materials. However silver formulations can vary in the size, solubility and aggregation of nanoparticles, meaning that there is no one single form of nano-silver (Wijnhoven 2009). As far as human exposure goes, a Danish report (Hagen Mikkelsen 2011) has found no quantitative data on occupational and consumer dermal exposure. The report believes that consumers especially may be exposed to nano-silver due to its relatively widespread use in clothes, and exposure is also suspected to be highest in the working environment. The main exposure routes for occupational settings are inhalation and skin contact, but further data on exposure and human toxicity are needed. As regards the environment, there is scientific evidence that nano-silver is toxic to aquatic and terrestrial organisms (Wijnhoven 2009, EPA 2010). Certainly, more research is needed on the bonds between nano-silver and the product it is incorporated in, and whether changes occur in the chemical properties. Nano-silver has latterly come under scrutiny from regulators, with the United States Environmental Protection Agency (EPA) deciding to look closely into it. In October 2011, the EPA published a notice that it was conditionally registering a pesticide product containing nano-silver as a new active ingredient. The product is used as a preservative for textiles. As a condition of registration, EPA is requiring additional data on the product that confirms that it will not cause unreasonable adverse effects on human health or the environment (EPA 2011).
15 15 In December 2011, the European Commission asked the SCENIHR 3 to prepare a scientific opinion for 2013 assessing whether the use of nano-silver, in particular in medical care and in consumer products, could result in additional risks compared to more traditional uses of silver, and to assess whether the use of nano-silver to control bacterial growth could result in resistance of micro-organisms. Multiwalled carbon nanotubes Carbon nanotubes are a new form of carbon where nanotechnology development has brought a ferment of fabrication and commercialization activity since There are different types of nanotubes: single-walled (SWNTs) double-walled (DWCNTs) and multiwalled (MWNTs), differing in the arrangement of their graphene cylinders. SWNTs have only a single layer of graphene cylinders; DWCNTs have two layers, and MWNTs have many layers (Sinha and Yeow 2005). The ISO defines multiwalled carbon nanotubes (MWCNTs) as carbon nanotubes composed of nested, concentric or near-concentric graphene sheets with interlayer distances similar to those of graphite. Their nano size, structure and topology give them unique mechanical properties like high stability, strength and stiffness, as well as special surface properties. In sum, they are stronger than steel but very light, offering much scope for practical applications, including the fabrication of reinforced fibres and nanocomposites, diverse uses for energy storage, spacecraft structures, and land and sea vehicles. They are also used in sports articles like tennis rackets, baseball bats, bicycle frames, skis and surfboards. Some types of MWCNT present great mechanical strength and heat-dissipation properties, conducting electricity much better than copper, and so are finding extensive applications in the electronics and computer industries. In the biomedical sector they have applications in radiotherapy, for sensors, as carriers for drug delivery and for implantable nanosensors and nanorobots. Probably the most on-trend and most marketed nanotechnology products are the MWCNTs. These are long, straight, multi-walled structures and regarded as the most perfect fibre that has ever been fabricated (Ajayan and Zhou 2001). Nevertheless, they have also shown adverse effects in animals, causing inflammation when deposited in the lungs and inducing asbestos-like effects. Scientists have, for example, reported that laboratory rodents when exposed to MWCNT develop mesothelioma (Poland 2008, Sakamoto 2009, Tagaki 2008). According to Ken Donaldson, a toxicologist at the University of Edinburgh specialized in workplace health, long fibres compared to short fibres have greater potency of proinflammatory and genotoxicity activity (Schinwald 2012). Since CNTs have specific properties related to strength and durability, they can be translated into biopersistence in the human body. The retention of long fibres in the parietal pleura initiates inflammation. Since fibres cannot be removed from the lung, the lesion aggravates and may give rise to mesothelioma. 3. Request for a scientific opinion on Nanosilver: safety, health and environmental effects and role in antimicrobial resistance, Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR). health/scientific_committees/emerging/docs/scenihr_q_027.pdf
16 16 MWCNTs may be pathogenic because they are (Donaldson 2006): Thin enough to get past the upper airways and into the areas of the lungs where oxygen diffuses into the bloodstream; Long enough to start harming the lungs because they break down natural defences found in the lungs; Durable in that they stick around for a long time without dissolving or being broken down by the body (biopersistence). Those characteristics length, diameter, biopersistence - are known as the fibre paradigm. Figure 3 Single-Walled and Multi-Walled Carbon Nanotubes Sources: Petrica Cristea 2013, Donaldson 2006 MWCNT can be fabricated by different methods and processing conditions, so special care must be taken at the workplace. The US National Institute of Occupational Health and Safety has determined that workers may be at risk of developing adverse respiratory health effects if exposed for a working lifetime at upper limits according to their own methods for measurement of airborne CNTs (NIOSH 2010). Workers safety and protection must have top priority when dealing with this material. It is crucial for workers to be given sufficient enough information on the main processes they might possibly be exposed to (synthesis, collection, handling, purification and packing). While there is yet no scientific consensus on the dose and time needed to cause adverse health effects, workers should not be exposed to airborne MWCNT in any circumstances. Routes of human exposure to nanoparticles Particles in the nano form have various shapes spheres, fibres, tubes, rings and planes and are very small and highly active. These are key parameters in determining biological impacts. Nanoparticles may enter the human body by inhalation, through the skin, by injection or ingestion. Inhalation is the main route of exposure to nanoparticles. Once inhaled, a substantial proportion of nanoparticles are likely to deposit uniformly in the respiratory tract; the smaller the particles, the further down the respiratory tract they go. They can be
17 17 deposited in the nasopharyngeal compartment, in the trachaeobronchial region and further in the alveolar region (or air sac), and may persist for a long time in the human body. Once in the body, nanoparticles can be translocated elsewhere by different routes. Because shape and size play an important role, they may enter the blood stream, and can be distributed throughout other organs. For example, close contact between the alveoli and the circulatory system means that nanoparticles can displace easily to other organs, like the liver, kidney, heart or spleen. Scientific evidence demonstrates that nanoparticles can also travel to the nervous system via the olfactory nerves and they may reach deeper brain structures affecting cardiac and nervous system functions (Oberdörster 2004, 2005). When particles enter inside cells they may interfere with normal functions, and may trigger inflammatory or immunological responses. This is an extremely important discovery to have made and occupational toxicologists are now beginning to understand the physicochemical nature of inhaled particles and its potential to show unrecognized biological effects (Maynard 2010). Ingestion is the second main route of exposure. Nanoparticles can enter the digestive tract through the mouth (including by hand to mouth). Swallowed particles can move through the digestive tract and intestines, and enter the bloodstream. A third possible route of exposure is absorption through the skin; the scientific literature is still divided on this, so materials should be handled to avoid skin contact. In a workplace setting, dermal exposure can come about through handling nanomaterials and contact with contaminated surfaces. Transdermal exposure may also occur where biomedical applications for diagnostic and therapeutic purposes require intravenous, subcutaneous, or intramuscular administration (Oberdörster 2005). Figure 4 Movement of nanoparticles in the human body Nanoparticles Cross of cell boundaries Lung Skin Intestines Blood stream Translocation to other organs Source: Author
19 Part 2 Working with nanoparticles 19 How can workers identify nanomaterials? The European Framework Directive on the safety and health of workers at work (89/391/EC, the so-called 1989 Framework Directive) is the legal framework for protecting workers at the workplace. Although it contains no specific provisions on nanomaterials, it does specify that the responsibility for workers safety and health lies on the employer. Generally, occupational health and safety has to be continuously improved and it is a worker s right to be involved in it. On 3 October 2012 the European Commission issued its Second Regulatory Review on Nanomaterials to assess the implementation of EU legislation for nanomaterials and respond to issues raised by the European Parliament, the Council and the European Economic and Social Committee. The Communication touches on some occupational health and safety aspects but fails to propose a consistent strategy for guaranteeing the protection of workers handling or in contact with nanomaterials. A final assessment on a review of occupational health and safety legislation will be made by the European Commission by At present, nanomaterials and nanoproducts cannot be easily identified as there is no obligation to label them, despite the no data, no market principle that underpins the REACH Regulation. The European Commission is discussing the classification, labelling and packaging of chemicals and nanomaterials under the REACH and CLP (1272/2008/EC) regulations which set the general framework to see how they might apply to nanomaterials. A European Parliament Resolution has called for consumer products to be labelled, and the nano-label was recently introduced in the Cosmetics Regulation (1223/2009/EC) published in the Official Journal of the European Union on
20 20 22 December 2009, and in the new EU Regulation on the provision of food information to consumers (1169/2011) published in the Official Journal of the European Union on 25 October Both regulations state that product ingredients in the form of nanomaterials must be indicated in the list of ingredients followed by the word nano in brackets. The situation becomes even more complex when it comes to the workplace. Nanotechnology workplaces may be either big or multinational companies, spin-off businesses from academia or any number of small and medium-sized companies, including retailers, where there is a flow of raw materials, unfinished products and end products in all directions. This mixed bag of situations makes it hard to identify which and how many jobs are nano-related and their working conditions, and so information does not flow easily along the value chain. Just as manufacturers and processors need to know what they are working with, retailers need to know what they are selling and workers need to know what they are handling. What activities involve working with nanomaterials? Occupational exposure to nanoparticles can occur in laboratories where nanomaterials are being produced and handled, and at workplaces where nanomaterials or nanoproducts are being produced, manufactured or processed. Workers are mainly exposed to nanoparticles in production processes at different stages filling, sampling, cleaning and maintenance work or in disruptions of normal operations. Where activities involve liquid media (e.g., precipitation reactions, dispersion in the liquid phase), ingestion by inhalation is usually precluded by avoiding aerosol formation. The Guidance on Safe Handling of Nanomaterials and Nanoproduct published by the Dutch Trade Union Confederation FNV (FNV 2010) recommends assessing the life cycle starting at the moment the materials or products enter the company and ending when those materials or products leave the company again as ready-for-use product or waste material. If those materials are modified or incorporated into another product, workers will also be exposed when handling, transporting, disposing of and recycling them. Activities at the workplace that may involve exposure to nanoparticles may include: Laboratory handling of nanopowders; Transfer, sampling and incorporation (into a mineral or organic matrix of nanopowders); Working in liquid media; Product recovery from reactors or filters; Direct leakage from reactors; Cleaning and maintenance of equipment or rooms (including reactor evacuation and filters); Processing and packaging of dry powder; Welding processes; Painting and sanding; Collection, transport and disposal of waste. The hierarchy of exposure controls elimination, substitution, engineering controls, work practice/administrative procedures, and personal protective equipment should be followed.