Engineered Nanoparticles; Current Knowledge about OHS [Occupational Health and Safety] Risks and Prevention Measures is the title for a report (2nd edition) written by Claude Ostiguy, Brigitte Roberge, Catherine Woods, and Brigitte Soucy for the Quebec-based Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST). From the news item on Nanowerk,
An initial assessment of the state of scientific knowledge about the occupational health and safety aspects (OHS) related to synthetic nanoparticles (NP) was published by the IRSST in 2006 and covered the scientific literature until the end of 2004. What was found was that OHS knowledge was very fragmentary but that research in this field was rapidly growing. This current document aims to assess the state of current knowledge in this field and summarizes the data available until early 2010.
Overall, what emerges is that NP remain an important source of concern in OHS. In fact, not only does the diversity of commercially available chemical products of nanometric dimensions continue to increase, but also, the information available about the hazards specific to these substances is still very fragmentary. The literature gives us very little information specific to NP relating to their physical hazards like fires or explosions.
In a context of incomplete data for the majority of nanometric substances, it remains impossible to quantify the risks for workers in the majority of situations because the toxicity of the products, the level of dust contamination of workplaces, or their potential to cause fires or explosions remain not extensively documented or totally undocumented. Nevertheless, the majority of the means of exposure control for ultrafine particles should be effective against NP and much research is currently being carried out to confirm this.
In a context of uncertainty about the risks, and with an increasing number of potentially exposed workers, the current report paints a big picture of the OHS knowledge currently available in the NP field. In the absence of specific standards, a preventive and even a precautionary approach are recommended, and a review of the available means for minimizing worker exposure is presented.
The report (over 150 pp.) can be found here. There’s certainly much to appreciate in the report. Here are two bits that I particularly want to highlight, the acknowledgment that nanoparticles aren’t new,
Although the development of NT [nanotechnology] is a modern multidisciplinary science, naturally produced and manmade materials of nanometric dimensions and exposure to particles of other dimensions of mineral or environmental origin, including the fine fraction of nanometric particles, have always existed. Some of the natural nanometric particles are of biological origin – including DNA with a diameter of around 2.5 nm and many viruses (10 to 60 nm) and bacteria (30 nm to 10 μm) — while others are found in desert sand, oil fumes, smog, and fumes originating from volcanic activity or forest fires and certain atmospheric dusts. Among those generated by human activity, we should mention diesel fumes, industrial blast furnace emissions and welding fumes, which contain particles of nanometric dimensions (Teague, 2004). (p. 11 PDF, p. 1, print)
There’s also a very good (in my opinion) description of bottom-up and top-down approaches to engineered nanoparticles,
Nanoparticles can be synthesized by different approaches. Nanoparticle production can be generally categorized into the bottom-up and top-down methods. In the bottom-up approach, nanoparticles are constructed atom-by-atom or molecule-by-molecule. In the top-down approach (top-down), a large structure is gradually underdimensioned, until nanometric dimensions are attained after application of severe mechanical stresses, violent shocks and strong deformations. The two approaches bottom-up and top-down tend to converge in terms of dimensions of the synthesized particles. The bottom-up approach seems richer, in that it allows production of a greater diversity of architectures and often better control of the nanometric state (relatively monodispersed granulometric sizes and distribution, positioning of the molecules, homogeneity of the products). The top-down approach, although capable of higher-volume production, generally makes control of the nanometric state a more delicate operation. (p. 25 PDF, p. 15 print)
Ostiguy (last mentioned in my June 23, 2010 posting [Nanomaterials, toxicity, and Canada’s House of Commons Standing Committee on Health] as an expert witness) and his colleagues offer a good overview of international, national, and provincial (Québec) research and development efforts including definitions for terms and descriptions of various types of nanoparticles and a discussion about markets. I was expecting something more narrowly focused on occupational health and safety (OHS) but very much appreciate the efforts to contextualize OHS issues within the larger nanotechnology ‘enterprise’ in addition to the OHS material.
Oddly, I found this on the cover page,
The IRSST makes no guarantee regarding the accuracy, reliability or completeness of the information contained in this document. In no case shall the IRSST be held responsible for any physical or psychological injury [??? and emphasis mine] or material damage resulting from the use of this information.
Note that the content of the documents is protected by Canadian intellectual property legislation.
As for any psychological injury I may received from reading the report, what about injury from reading the disclaimer?
I do have a few nits to pick. Surprisingly since this report was published in July 2010, they did not include any information about an April 2010 nanomaterial definition proposed in the US (my April 27, 2010 posting). More picayune, reference is made to Nanotech BC which has been effectively defunct since Spring 2009 while no mention is made of Nano Ontario which I first noticed in early 2010 (Professor Gilbert Walker responded on behalf of Nano Ontario to Peter Julian’s proposed nanotechnology legislation in my March 29, 2010 posting).
I was also surprised at the certainty expressed about scientific unanimity over the dimensions,
As already mentioned, there is now unanimity in the scientific community on the dimensions of manufactured NP: at least one of their dimensions ranges between one and 100 nm [emphasis mine] and they have different properties than larger-diameter particles made of the same material (ASTM, 2006; BSI, 2008; ISO, 2007, 2008). (p. 49 PDF, p. 39 print)
As I understand it, there’s still some discussion about the one to one hundred nanometre range as I note here in my July 14, 2010 posting,
The comment about the definition sprang out as this issue seems to be at the forefront of many recent discussions on nanotechnology. Fern Wickson and her colleagues highlight the importance of the issue in their recently published paper,
Both the beginning and the end of this range remain subject to debate. Some claim that it should extend as low as 0.1nm (because atoms and some molecules are smaller than 1nm) and as high as 300nm (because the unique properties of the nanoscale can also be observed above 100nm). The boundaries of ‘the nanoscale’ are highly significant in both scientific and political terms because they have the possibility to affect everything from funding, to risk assessment and product labelling. [my commentary, Wickson’s response, and a citation for the paper, etc. can be found in my July 7, 2010 posting]
I do recommend reading the IRSST report if this sort of thing interests you as it offers answers to questions that you may (and, in my case, certainly) have been asking yourself about quantum dots, carbon black, and the state of OHS research and regulations in Canada and elsewhere.