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Posted: October 3, 2008
NIOSH updates on nanotechnology risk research
(Nanowerk News) Recent accomplishments by the National Institute for Occupational Safety and Health (NIOSH) highlight the agency's leadership in collaborative research to determine if workers are at risk of job-related illness or injury in the production and industrial use of nanomaterials. The accomplishments include two new peer-reviewed papers, two new international partnerships, and a professional award.
"NIOSH's strategic research program continues to add to the body of knowledge on the safety and health implications and applications of nanotechnology," said NIOSH Acting Director Christine M. Branche, Ph.D. "Diverse stakeholders agree that studies and partnerships such as ours are important for the responsible development of nanotechnology and U.S. leadership in this global market."
In a study by NIOSH scientists and outside colleagues, mice that inhaled carbon nanotubes from an aerosol suspended in the air showed the same dose-related effects as mice that were exposed in past studies through a different method, the direct aspiration of carbon nanotubes into the lung. The findings were reported in the American Journal of Physiology: Lung Cell and Molecular Physiology. Effects included the formation of granulomas (lumps) in the lungs of exposed mice, and lung tissue fibrosis. Due to the lack of workplace exposure data, scientists are unable at present to predict whether workers would experience similar effects through workplace exposures, or whether the effects would signal a risk for impairment or death, either in and of themselves or as precursors to other effects. However, the findings advance the data needed for designing and pursuing further high-quality research that is critical for addressing those questions ("Inhalation vs. aspiration of single-walled carbon nanotubes in C57BL/6 mice: inflammation, fibrosis, oxidative stress, and mutagenesis").
Evaluations of NIOSH-approved N95 and P100 filtering-facepiece respirators for reducing exposures to nanometer-sized silver aerosol particles supported previous studies which found that such respirators should provide expected levels of protection against nanoparticles, when fitted, maintained, and used properly. In this study, NIOSH researchers found that the respirators were highly efficient in capturing particles that were 4 to 30 nanometers in size, and became increasingly efficient as particles became smaller. This is because smaller particles wander or wobble more in their path as they pass through a filter, and are more likely to be captured or caught by the filter's fibers. Previous reports had suggested that particles less than 20 nanometers would not be captured as efficiently as expected due to thermal effects which would cause the particles to bounce off the fibers during collisions. However, this study found no evidence for thermal rebound of particles as small as 4 nanometers ("Filtration Performance of NIOSH-Approved N95 and P100 Filtering Facepiece Respirators Against 4 to 30 Nanometer-Size Nanoparticles")
Four NIOSH researchers representing combined interdisciplinary expertise in laboratory and field studies are part of a new international research partnership, the International Alliance for NanoEHS Harmonization (IANH). The alliance plans to establish scientific protocols to promote harmonization in the toxicological testing of nanomaterials. As research accelerates, this work is important for correlating studies, reducing uncertainties about results, and comparing with confidence the results of in vivo and in vitro studies. The effort builds in part on scientific methodology that NIOSH has developed or helped develop, and lessons learned from its pioneering research.
NIOSH is leading the formation of a workshop by the Organization for Economic Cooperation and Development (OECD) on the assessment and mitigation of workplace exposures to nanomaterials. The workshop is scheduled to be held on October 20, 2008, in Frankfurt, Germany. In the workshop, representatives of the OECD Working Party on Manufactured Nanomaterials and invited outside experts will explore latest developments, needs, and opportunities in research. The workshop will further international dialogue and collaboration on occupational safety and health of nanotechnology.
The Richard C. Knudson Publication Award, 2008, was presented by the American Biological Safety Association for the paper "Biosafety, Occupational Health, and Nanotechnology," published last year in the journal Applied Biosafety (Applied Biosafety, 2007, 12(3), 158-167). The authors of the paper are Vladimir V. Murashov, Ph.D., Special Assistant to the Director, NIOSH, and John Howard, M.D., former Director of NIOSH. The award recognizes "significant contributions in areas of scientific investigation and/or health and safety."