Tag Archives: Maximilien Debia

Canadian research into nanomaterial workplace exposure in the air and on surfaces

An August 30, 2018 news item on Nanowerk announces the report,

The monitoring of air contamination by engineered nanomaterials (ENM) is a complex process with many uncertainties and limitations owing to the presence of particles of nanometric size that are not ENMs, the lack of validated instruments for breathing zone measurements and the many indicators to be considered.

In addition, some organizations, France’s Institut national de recherche et de sécurité (INRS) and Québec’s Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) among them, stress the need to also sample surfaces for ENM deposits.

In other words, to get a better picture of the risks of worker exposure, we need to fine-tune the existing methods of sampling and characterizing ENMs and develop new one. Accordingly, the main goal of this project was to develop innovative methodological approaches for detailed qualitative as well as quantitative characterization of workplace exposure to ENMs.

A PDF of the 88-page report is available in English or in French.

An August 30, 2018 (?) abstract of the IRSST report titled An Assessment of Methods of Sampling and Characterizing Engineered Nanomaterials in the Air and on Surfaces in the Workplace (2nd edition) by Maximilien Debia, Gilles L’Espérance, Cyril Catto, Philippe Plamondon, André Dufresne, Claude Ostiguy, which originated the news item, outlines what you can expect from the report,

This research project has two complementary parts: a laboratory investigation and a fieldwork component. The laboratory investigation involved generating titanium dioxide (TiO2) nanoparticles under controlled laboratory conditions and studying different sampling and analysis devices. The fieldwork comprised a series of nine interventions adapted to different workplaces and designed to test a variety of sampling devices and analytical procedures and to measure ENM exposure levels among Québec workers.

The methods for characterizing aerosols and surface deposits that were investigated include: i) measurement by direct-reading instruments (DRI), such as condensation particle counters (CPC), optical particle counters (OPC), laser photometers, aerodynamic diameter spectrometers and electric mobility spectrometer; ii) transmission electron microscopy (TEM) or scanning transmission electron microscopy (STEM) with a variety of sampling devices, including the Mini Particle Sampler® (MPS); iii) measurement of elemental carbon (EC); iv) inductively coupled plasma mass spectrometry (ICP-MS) and (v) Raman spectroscopy.

The workplace investigations covered a variety of industries (e.g., electronics, manufacturing, printing, construction, energy, research and development) and included producers as well as users or integrators of ENMs. In the workplaces investigated, we found nanometals or metal oxides (TiO2, SiO2, zinc oxides, lithium iron phosphate, titanate, copper oxides), nanoclays, nanocellulose and carbonaceous materials, including carbon nanofibers (CNF) and carbon nanotubes (CNT)—single-walled (SWCNT) as well as multiwalled (MWCNT).

The project helped to advance our knowledge of workplace assessments of ENMs by documenting specific tasks and industrial processes (e.g., printing and varnishing) as well as certain as yet little investigated ENMs (nanocellulose, for example).

Based on our investigations, we propose a strategy for more accurate assessment of ENM exposure using methods that require a minimum of preanalytical handling. The recommended strategy is a systematic two-step assessment of workplaces that produce and use ENMs. The first step involves testing with different DRIs (such as a CPC and a laser photometer) as well as sample collection and subsequent microscopic analysis (MPS + TEM/STEM) to clearly identify the work tasks that generate ENMs. The second step, once work exposure is confirmed, is specific quantification of the ENMs detected. The following findings are particularly helpful for detailed characterization of ENM exposure:

  1. The first conclusive tests of a technique using ICP-MS to quantify the metal oxide content of samples collected in the workplace
  2. The possibility of combining different sampling methods recommended by the National Institute for Occupational Safety and Health (NIOSH) to measure elemental carbon as an indicator of NTC/NFC, as well as demonstration of the limitation of this method stemming from observed interference with the black carbon particles required to synthesis carbon materials (for example, Raman spectroscopy showed that less than 6% of the particles deposited on the electron microscopy grid at one site were SWCNTs)
  3. The clear advantages of using an MPS (instead of the standard 37-mm cassettes used as sampling media for electron microscopy), which allows quantification of materials
  4. The major impact of sampling time: a long sampling time overloads electron microscopy grids and can lead to overestimation of average particle agglomerate size and underestimation of particle concentrations
  5. The feasibility and utility of surface sampling, either with sampling pumps or passively by diffusion onto the electron microscopy grids, to assess ENM dispersion in the workplace

These original findings suggest promising avenues for assessing ENM exposure, while also showing their limitations. Improvements to our sampling and analysis methods give us a better understanding of ENM exposure and help in adapting and implementing control measures that can minimize occupational exposure.

You can download the full report in either or both English and French from the ‘Nanomaterials – A Guide to Good Practices Facilitating Risk Management in the Workplace, 2nd Edition‘ webpage.

ÉquiNanos, Québec’s innovative nanoparticle risk management team

ÉquiNanos as described in the January 2013 issue of Nanomedicine: Nanotechnology, Biology, Medicine is both the name for an interdisciplinary nanoparticle risk management team and a model for managing that risk.

Before going further, here’s a citation and a link (if you want to see the article for yourself it is behind a paywall but everyone can get access to the abstract),

EquiNanos: innovative team for nanoparticle risk management by Sylvie Nadeau, Michèle Bouchard, Maximilien Debia, MSc, Nathalie DeMarcellis-Warin, Stéphane Hallé, Victor Songmene, Eng, Marie-Christine Therrien, Kevin Wilkinson, Barthélémy Ateme-Nguema, Geneviève Dufour, André Dufresne, Julien Fatisson, Sami Haddad, Madjid Hadioui, Jules Kouam, François Morency, Robert Tardif, Martin Viens, Scott Weichenthal, Claude Viau, Michel Camus. Nanomedicine. 2013 Jan;9(1):22-4. doi: 10.1016/j.nano.2012.08.003. Epub 2012 Sep 6.

Here’s how the Québec-based and funded authors define the issues, excerpted  from the ÉquiNanos article (Note: Footnotes have been removed),

… Lack of proper evaluation of real risks might threaten to undermine the competitiveness of nanotechnologies. In spite of multiple efforts for more general regulations, and there is currently no specific regulation governing particle size-distribution, and no consensus on the benefits of protection or on the level of safety afforded by proposed protective measures. The different perspectives of the various actors (scientists, industrials, workers, the Occupational Safety and Health Commission (CSST-Quebec), legislators, independent technologies promoters, media, public) regarding risk management reveal the need for an inter-sector approach that allows all groups to achieve their goals. …

Business organizations must manage risks associated with NP in a climate of scientific uncertainty, in the absence of a regulatory framework specifically adapted to NP and without a proven effective and efficient approach to risk management.

This is their proposed model,

ÉquiNanos consists of eight platforms (…): Adaptive decision-aid tool, public and legal governance, communication of risks, monitoring nano-aerosols at the source, evaluation and control of exposure, biological and kinetic monitoring, manufacturing,and preventative actions. Their coordination is based on a functionalistic research-action model allowing the ÉquiNanos team to get involved directly in order to transform business reality and to produce knowledge related to these transformations through communication with all stakeholders and agents of governance. The melting of disciplines and knowledge is the foundation of our inter-sector model.

The authors have provided a diagram of their proposed model,

Figure 1. Functionalistic research-action model – ÉquiNanos (OHS: Occupational Health and Safety). [downloaded from http://www.sciencedirect.com.proxy.lib.sfu.ca/science/article/pii/S1549963412005175]

Figure 1. Functionalistic research-action model – ÉquiNanos (OHS: Occupational Health and Safety). [downloaded from http://www.sciencedirect.com.proxy.lib.sfu.ca/science/article/pii/S1549963412005175]

Not surprisingly Dr. Claude Ostiguy and Dr. Andrew Maynard are both cited in the reference. Both are well known for their work in the field of risk management of nanoparticles and nanomaterials and were mentioned in my July 26, 2011 posting about a, then recent, sensationalist and somewhat inaccurate  nano risk article published in the Georgia Straight.

Équinanos looks like a reasonable model although implementation issues abound. Are businesses going to voluntarily participate? What percentage of businesses will volunteer? What about nanotechnology-enabled products that are manufactured elsewhere? What mechanism is there for transmitting and sharing information? No doubt these questions and more are being considered. It will be interesting to see if or how they manage to address these issues.