Nanotechnology at work can hurt
NIOSH urges precautions until risks are known
The emerging field of nanotechnology — the science of "building small" — holds enormous promise in almost every field, including medicine, cosmetics, information technology, optics, electronics, and materials development.
Devices measured on the nanoscale are smaller than viruses, from 100 to 10,000 times smaller than human cells, and as such can easily enter human cells. A nanometer is one-billionth of a meter; a human hair, by comparison, is about 80,000 nanometers wide. (See Table 1.)
Occupational health nurses who work with employees involved in industries that are or will be using or developing nanotechnology should be aware that there are many unanswered questions about what effects such tiny, yet powerful, devices can have on the health of those exposed to them.
Epidemiologist Linda A. McCauley, PhD, FAAN, professor of nursing and associate dean for research at the University of Pennsylvania School of Nursing, says that while our knowledge of what health risks may accompany exposure to nanodevices is limited at this point, the first thing an occupational health nurse needs to know is whether her company is already using nanotechnology. "Nurses should keep their radar up about new processes, keep their ears open, and stay informed about new technologies being developed," she suggests. Nurses should also stay abreast of toxicological testing done on nanomaterials used in their workplaces.
Nanotechnology already in use
No longer confined to research and theoretical usefulness, nanotechnology's value in clinical applications has already been proven in several areas, and some nanodevices are already in use. (See Table 2.)
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Table 2. Now available, soon to come, courtesy of nanotechnology Products already available that use nanoscale materials: Materials or processes in development using nanotechnology: Source: National Institutes for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention, Atlanta. |
Nanomaterials include tiny spheres, disks, tubes, and wires. They are not all man-made nanoscale particles occur naturally in nature, and we encounter them whenever the wind blows or we dig in soil.
According to the National Cancer Institute (NCI), part of the National Institutes for Health, first-generation nanoscale devices — liposomes — are in use as drug delivery vehicles in several products, including liposomal amphotericin B, used to treat fungal infections associated with aggressive anticancer treatment, and liposome doxorubicin, used to treat some forms of cancer.
Researchers have shown that nanoparticulate iron oxide particles can be used with magnetic resonance imaging (MRI) for nonsurgical detection of metastatic lesions in lymph nodes, and in 2004 the Food and Drug Administration accepted a new drug application from American Pharmaceutical Partners and American BioScience for a form of the anticancer drug Taxol using nanoparticulates.
Because nanoparticles are so tiny and so precise, research has shown that they can immediately detect when a cancer cell dies, a potentially lifesaving boon to patients and clinicians who would not have to wait weeks before knowing whether a particular therapy is working or not. Non-lifesaving uses carry substantial moneymaking weight, as well; because some nanoparticles reflect light, their value to the cosmetics industry is already recognized.
"Nanoparticles can reflect light, so is it any wonder that sunblocks work better and don't have to contain [opaque, white] zinc oxide?" points out McCauley.
Understandably, findings such as these have fueled the desire to make use of these microscopic tools as quickly as they can be proved.
McCauley wrote recently in the AAOHN Journal that data indicate that by 2010, there will be a $10 billion global demand for nanoscale materials, tools, and devices, and more than 2 million people will work in and in support of nanotechnology worldwide.1
The federal government, through its National Nanotechnology Initiative, has budgeted more than $1 billion in research funding for nanotechnology in 2007, but less than one-half of 1% is directed to studying workplace safety.
Worker safety still an unknown
The National Institute for Occupational Safety and Health (NIOSH) has undertaken extensive research into the safety implications for workers who are involved in the production and testing of nanodevices. However, McCauley says to her knowledge, there have been no published studies of human health studies.
"NIOSH is looking at worker health and looking at how effective respirators are in protecting workers," she says. The extent to which respirators can protect workers exposed to nanoparticulates is still unknown, given that many are smaller than viruses.
NIOSH recently partnered with Reno, NV-based Altair Nanotechnologies Inc. — at Altair's request — to measure worker exposures to nanoparticles during the manufacturing process.
Many nanomaterials and devices are formed from nanometer-scale particles that are initially produced as aerosols or colloidal suspensions. Workers can potentially be exposed to uniquely engineered materials with novel sizes, shapes, and physical and chemical properties, at levels far exceeding ambient concentrations. Exposure during manufacturing and use can occur through inhalation, dermal contact, and ingestion.
McCauley says she became interested in nanotechnology when, because of her experience in reviewing studies in the workplace, she was asked by the Environmental Protection Agency to review some nanotechnology grant applications.
She has since published several papers on the subject of nanotechnology and occupational health, and will present on the subject at the 2006 AAOHN Expo.
McCauley points out that the source of many of the concerns about the health and environmental impacts of nanomaterials is the lack of information about the risks. What is known is that potential harmful effects can stem from the nano-devices themselves, products made with them, or from the manufacture of nanoparticles.
"They're smaller than viruses, so will they permeate latex gloves? Those are some of the occupational exposure questions to consider," she says. "They don't act like other things we know."
NIOSH recommends companies take interim precautionary measures "until further information on the possible health risks and extent of occupational exposure to nanomaterials becomes available," according to NIOSH's nanotechnology website (www.cdc.gov/NIOSH/topics/nanotech).
These interim measures should focus on developing safe working practices tailored to the specific processes at each worksite, with consideration for the hazards posed by common materials being manufactured in the nanometer range, NIOSH advises.
Until further information on the possible health risks and extent of occupational exposure to nanomaterials becomes available, interim precautionary measures should be developed and implemented. These measures should focus on the development of safe working practices tailored to specific processes and materials where workers might be exposed.
Hazard information that is available about common materials that are being manufactured in the nanometer range (for example, TiO2) should be considered as a starting point in developing any work practices.
Factors for the occupational health nurse to consider include the amount of nanomaterial being used, how easily it can be dispersed or form sprays (powders and suspensions), and the degree of containment and duration of use.
NIOSH guidelines say in the case of airborne particles or droplets, size determines whether the material can enter the respiratory tract. Inhaled particles smaller than 10 micrometers (mcm) in diameter have some probability of penetrating to and being deposited in the gas exchange region of the lungs; nanoparticles known as "buckyballs" or fullerenes are approximately 0.001 mcm across. (See Table 3.)
Table 3. Potential for nano-material exposure Workplace factors that can increase the potential for exposure, according to NIOSH, include: Source: National Institute for Occupational Safety and Health (NIOSH), Centers for Disease Control and Prevention, Atlanta. |
"There is concern about releasing particles into the environment in amounts we don't want them released," McCauley says of environmental concerns regarding nanoparticles.
Nanoparticles have been used to rid water and soil or pollution, McCauley explains, but she adds, "There's also the concern that we're leaving behind [following cleanups] something that might be a concern in itself." n
Reference
1. McCauley LA, McCauley RD. Nanotechnology: Are occupational health nurses ready? AAOHN Journal 2005;53:517-521.
[For more information, contact:
Linda A. McCauley, PhD, FAAN, professor of nursing, associate dean for research, University of Pennsylvania School of Nursing, Philadelphia. E-mail: [email protected].
National Cancer Institute resources for nanotechnology in research and treatment of cancer: http://nano.cancer.gov.
National Institutes for Occupational Safety and Health, section on nanotechnology: www.cdc.gov/niosh/topics/nanotech.]
The emerging field of nanotechnology — the science of "building small" — holds enormous promise in almost every field, including medicine, cosmetics, information technology, optics, electronics, and materials development.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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