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February 9, 2015

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Ask the professionals: Nanotechnology

Each month, SHP asks a professional working in a specialist field to share their expertise. Steve Hankin highlights the emerging field of nanotechnology and nanomaterials and how to mitigate their impact on health and safety.

What is nanotechnology?
Nanotechnology is being applied in a wide range of industrial and technological sectors, including food, information technology, energy, environment, security, textiles, and medicine, among others.

Nanotechnology is the application of scientific knowledge to manipulate and control matter in the nanoscale (size range from approximately 1 – 100 nanometre (nm)) in order to make use of size and structure-dependent properties and phenomena, distinct from those associated with individual atoms, molecules or larger-scale materials.

From a health and safety perspective, it is more typically nanomaterials – chemical substances or materials that are manufactured and used to exploit novel characteristics compared to the bulk material such as increased strength, chemical reactivity or conductivity – and not nanotechnology that’s regulated and the subject of conventional risk assessment.

How do I determine if my material is classed as a ‘nanomaterial’?
To determine if a material is classed as a ‘nanomaterial’ according to the European Commission’s recommendation on a definition[1], physico-chemical characterisation of the material is required in order to obtain the number size-distribution information. This can be obtained using laser light diffraction/ dynamic light scattering techniques to determine the percentage of particles within the sample that are below 100 nm. If 50 per cent or more of the particles in the number size distribution have one or more external dimensions in the size range 1 – 100 nm, then the material is classed as a nanomaterial in accordance with the EC definition.

How are nanomaterials being regulated?
The regulation of nanomaterials and nanoenabled products is a dynamic and evolving activity, due largely to the wide range of nanomaterials, nano-enabled products, and applications that are being developed and the uncertainties that are associated with defining, characterising, and appropriately testing them for efficacy and safety.

Regulatory bodies in the EU, US, Canada, Australia and a limited number of other countries have initiated activity to assess, and in some cases ensure, the coverage of nanomaterials under existing substances and products regulations. In Europe, the EC has undertaken two regulatory reviews on nanomaterials, assessing the adequacy and implementation of EU legislation for nanomaterials.[2]

Although it has been concluded that nanomaterials are in principle covered by the various existing regulatory frameworks, it is acknowledged that there are difficulties at the implementation level due to the lack of available safety information needed for hazard and risk assessments. As such, additional measures and guidance may be needed to support the nanomaterials industry and work is in progress to meet these needs.

Specific provisions on nanomaterials have been introduced into several consumer product legislations, including for biocides, cosmetics, food and food contact materials, and a number of mandatory reporting schemes have emerged in European member states for nanomaterials.

Is there a quantity threshold for nanomaterial registries and regulations?
A number of countries (including France, Belgium and Denmark, at the time of writing) have introduced mandatory reporting schemes to gather available information on nanomaterials related to their production, properties and application. Under these schemes, manufacturers and importers of nanomaterials at a certain tonnage threshold must provide specific information on an annual basis to ensure compliance.

Both the French and Belgian mandatory reporting schemes require information to be provided from manufacturers and importers of nanomaterials in quantities of 100g or more per annum. The Danish reporting scheme mentions no such quantity threshold, and applies to all companies that manufacture or import mixtures or articles incorporating nanomaterials that are intended for sale to the Danish general public.

The European Registration, Evaluation and Authorisation of Chemicals (REACH) Regulation requires a manufacturer or importer of any nanoscale substance, or a producer or importer of nanoscale substances contained in articles, in volumes of one tonne or more per year to register the substance and prepare a technical dossier. At the time of writing, no specific provisions have been made for nanomaterials in the REACH Regulation.

What do I need to do to demonstrate a responsible approach and comply with the law?
A vital aspect of the successful and responsible development and commercialisation of nanomaterials and nanotechnology-enabled products is sustained awareness of regulatory developments and a proactive approach to ensuring compliance.

A strategy to ensuring good practice in relation to regulatory compliance could include a number of activities such as:

  • implement and sustain good governance, embedding nanomaterials safety in an effective health and safety management process;
  • actively monitor new regulatory developments at a national, regional and international level;
  • understand and meet requirements, document and provide to comply with the regulations and reporting schemes;
  • engage with the public dialogue to build consumer acceptance and confidence in the technology; and
  • participate in voluntary initiatives to support the safe use of nanomaterials (e.g. adopting a code of conduct for nanotechnologies).

How can I determine if nanomaterials are released from a process?
Exposure assessment involves the measurement or estimation of emissions, considering pathways of exposure and influencing factors, in order to obtain concentrations to which workers might be exposed.

Although normal ambient air, whether in the environment or indoors, already contains a large number of particles in the nanometre size range, a well-planned exposure monitoring campaign – using a combination of real-time direct reading instruments, filter sampling and contextual observations – can help to identify the presence of any process-related particles that pose a potential inhalation hazard to health (which of course should include consideration of all respirable-sized particles, and not just nano-sized particles). Several international standards exist for exposure monitoring of airborne particles in the workplace, for example, ISO/TR 27628:2007.[3]

How can nanomaterials be controlled in the workplace?
Employers have a general duty to ensure the health and safety of workers in all aspects related to their work, including any possible risks associated with working with nanomaterials. This is achieved by the development of a risk management programme, conducting regular risk assessments, which should be informed by an exposure assessment and result in the implementation of a control strategy.

As for any other chemical, appropriate steps should be taken to minimise worker exposure to nanomaterials by applying protection measures, appropriate to the activities and consistent with the ‘hierarchy of control’. Verification/confirmation is of course essential to ensure that the implemented tools and strategies are performing as specified.

Are there any workplace safety levels (e.g. OELs) for nanomaterials?
Currently, no regulatory occupational exposure limit (OEL) for engineered nanomaterials has been set, although they are being considered both in Europe and elsewhere. In the US, the National Institute of Occupational Safety and Health (NIOSH) has proposed Recommended Exposure Limits (REL) for:

  • respirable carbon nanotubes and carbon nanofibres – worker exposure should not exceed 1.0 micrograms per cubic meter (μg/m3) as an eight-hour time-weighted average;
  • ultrafine (nano-scale) titanium dioxide – worker exposure should not exceed 0.3 mg/m3 as an eight-hour time-weighted average; and
  • pigmentary titanium dioxide (particle size greater than 100 nm) – worker exposure should not exceed 2.4 milligrams per cubic meter (mg/m3) as an eight-hour time-weighted average).

In addition, a number of companies have developed in-house exposure limits. There exists a degree of variability in the suggested limits, partly due to the data set upon which the exposure limit is based, but also the nature of the derivation process, including what safety factors are applied.

Despite this, it is clear that certain nanoparticles may be more hazardous than larger particles of the same substance. Therefore, existing occupational exposure limits for a substance may not provide adequate protection from nanoparticles of that substance. Employers should seek to minimise worker exposure by using appropriate exposure control measures.

What guidance and help is available?
A multitude of general and specific guidance, standards and journal articles relevant to nanomaterials safety have been published, including on safe handling and control, exposure assessment, hazard assessment, risk assessment, and control banding. It can be a little daunting to know where to start, but a number of information hubs, for example, www.safenano.org, provide easy access to key guidance, information and services available to support the safety community.

Steve Hankin is head of SAFENANO at the Institute of Occupational Medicine and a senior consultant in chemical risk assessment. He leads a team of scientists providing research and consultancy services in exposure measurement, toxicology and risk assessment.

 

References:
1. European Commission Recommendation of 18 October 2011 on the definition of nanomaterial (2011/696/EU): http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32011H0696.

2. http://ec.europa.eu/environment/chemicals/nanotech/index_en.htm

3. ISO/TR 27628:2007 “Workplace atmospheres – Ultrafine, nanoparticle and nano-structured aerosols – Inhalation exposure characterization and assessment”.

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