7. Nanotechnology Research6.7 Letters of Support, Etc. | 7.1 RDRP Publications of Special Note Relating to Nanotechnology
This chapter provides information on nanotechnology research, and specifically exposure to engineered nanoparticles. Nanotechnology is the term used to describe new methods that have been developed to manipulate and build materials at the molecular level, and engineer materials at a scale of less than 100 nm (one tenth of one millionth of a meter).180 New materials, structures, and devices are being developed and produced that exhibit unique physical, chemical, and biological properties. There are currently no reports that associate exposure to engineered nanoparticles with a specific respiratory disease, however, RDRP’s long history of investigating health effects associated with ultrafine particulate exposures alerts us to a potential new threat. RDRP is developing five primary nanotechnology research areas: risk assessment for potential exposure-response; quantitative metrology; needs for risk management recommendations; needs for medical evaluation, surveillance and epidemiology; and nanotechnology applications in occupational disease prevention. Since February 2004, these five primary areas of investigation noted above have guided the development of a strategic research plan (A7-1) that contains 10 critical topic areas of activity specific to understanding the health and safety implications of developing, producing, or using engineered nanoparticles, and the potential applications of nanotechnology in the prevention of occupational disease and injury.
The U.S. Government is currently investing approximately $1 billion per year in nanotechnology research and development, under the coordination of the National Nanotechnology Initiative. It is estimated that the global nanotechnology market will be worth over $2.6 trillion by 2015, and will involve approximately two million new workers worldwide.
Nanoparticles present a very large surface area to mass ratio and their toxic effects appear to be increased accordingly. Early evidence from mammalian toxicity studies indicates that this new class of materials engineered nanoparticles, exhibit new or increased reactivity and increased toxic effects following inhalation exposure.181 Workplace exposure to engineered nanoparticles represents an area of unknown hazard with uncharacterized risk for which there is currently a lack of consistent guidance for their safe handling.
RDRP has begun inhalation toxicology studies using specific engineered nanoparticles. Completed experiments in laboratory animals (rats) have demonstrated that exposure to nanoparticles results in oxidative stress, inflammation, and fibrosis following inhalation exposures. RDRP is also conducting experiments to develop and validate methods for quantitative risk assessment models and for worker exposure assessment.
RDRP scientists are developing quantitative metrology to measure and characterize exposure to nanoparticles in the workplace and to evaluate controls. New instrumentation is being evaluated to determine its ability to quantitatively measure and characterize nanoparticle aerosols. The behavior of airborne nanoparticles is being characterized to help determine accurate and reproducible workplace exposure assessments. Engineering controls are being evaluated for their effectiveness in minimizing inhalation exposure to engineered nanoparticles; personal protective equipment, primarily respirators, is being evaluated for its effectiveness for protection against engineered nanoparticles.
RDRP is developing guidance on safe handling of nanomaterials. Safety issues in the workplace concerning flammability and explosivity of nanomaterials are being investigated.
RDRP is also developing interim risk management recommendations for release at regular intervals. Research results are being communicated and education products are being developed and deployed.
Outputs and Transfer
In response to the concerns that have been raised regarding the possible hazards and risks associated with producing or using engineered nanoparticles, RDRP scientists joined in the creation of the NIOSH Nanotechnology Research Center (NTRC). To guide the activities of the center, RDRP scientists in the NTRC developed the document “Strategic Plan for NIOSH Nanotechnology Research: Filling the Knowledge Gaps,” September 2005 (A7-1). The strategic plan provides a guide for building a research effort capable of responding to the challenges of this emerging technology.
RDRP scientists used this plan to develop a research program that has, in a very timely manner, resulted in the release of important technical publications, reports, recommendations, and resources to guide the nanotechnology research community. These include the NIOSH Web-based documents: “Approaches to Safe Nanotechnology” (A7-2), “Nanoparticle Information Library” (A7-3), and “NIOSH, Nanotechnology, and Occupational Safety and Health—Frequently Asked Questions” (A7-4).
In addition, RDRP scientists have published 27 literature reports, 43 abstracts and meeting proceedings, 5 other public documents (A7-5), and made more than 170 invited and contributed presentations at technical meetings, conferences or special symposia on occupational health aspects of nanotechnology (A7-6).
A particularly important RDRP publication in the American Journal of Physiology (1, A7-7) reports the toxicity of nanoparticles to the rat respiratory system. This seminal report received the 2006 Alice Hamilton Award (Biological Sciences category) and was also nominated for CDC’s prestigious Charles C. Shepard Science Award.
RDRP scientists have participated on national and international technical committees and workgroups charged with the task of developing engineered nanoparticle classification methods to assist in the standardization of toxicology testing. For example, the influential and highly cited publication entitled “Principles for characterizing the potential human effects from exposure to nanomaterials: elements of screening strategy” (2, A7-8) resulted from one of these international collaborations. Other examples of RDRP collaborations on nanotechnology are attached (A7-9). An example of congressional testimony by an industry leader in support of federal research on safe nanotechnology is also provided (A7-10).
Because of the rapid evolution of this technology, RDRP scientists are involved in the direct development of specific outreach activities as a part of the outreach component of the Strategic Plan for NIOSH Nanotechnology Research. These activities include planning of symposia, presenting research findings, and conducting workshops. We planned and implemented the First International Symposium on Nanotechnology and Occupational Safety and Health in Buxton, UK, in 2004, the Second International Symposium in Minneapolis, MN, in 2005, and we are working on the Third International Symposium to be held in Taiwan in 2007. In addition, we organized and presented extensive research results at the “First International Meeting on Nanotoxicology: Biomedical Aspects” in 2006, and we have developed and delivered a half-day professional development training course that focuses on the inhalation toxicology of engineered nanoparticles and recommendations on risk management practices intended to eliminate inhalation exposure.
As a result of the production of “Approaches to Safe Nanotechnology”and other RDRP activities, the U.S. was able to provide strong international leadership and vision during formation of the new International Standards Organization (ISO) Technical Committee on Nanotechnologies; this resulted in the U.S. being granted the chairmanship of the Working Group on Safety and Health Standards.
RDRP scientists are currently conducting inhalation toxicology testing on a series of engineered nanoparticles. Study results will support the development of a quantitative dose-response risk assessment model. Concurrent with the inhalation studies, the RDRP field team will continue to visit nanomaterial production facilities to characterize workplace inhalation exposures. Risk management practices recommended by RDRP will be incorporated into the proposed EPA voluntary nanomaterial stewardship program.
Intermediate Goal and ObjectivesMoving Forward
The intermediate goal of RDRP research is to prevent respiratory and other diseases potentially resulting from workplace exposure to engineered nanoparticles.
To accomplish this, the following objectives have been developed: