Keystone, Colo.—As more workers get exposed on the job to tiny new nanomaterials with unknown medical risks, government watchdogs are looking at ways to keep tabs on their health. One solution may lie in the breath.
Emerging technology, still under development, examines exhaled breath to look for indicators of early stage lung problems – problems that scientists think could be caused by exposure to nanomaterials.
The idea elicited a few gasps of excitement at a nanotechnology conference convened here last week by the National Institute for Occupational Safety and Health (NIOSH), a federal agency that conducts research and makes recommendations in occupational safety and health.
About 140 people from 10 countries gathered for the conference, the first-ever U.S. convening to tackle occupational safety issues in the nanotech industry.
Nanotechnology manipulates matter on a near-atomic scale in order to develop nanomaterials with surprising new properties, such as strength and super-conductivity. Nano-enahnced consumer, environmental and health products have spawned a red-hot industry. A nanoparticle is defined as a particle with dimension of less than 100 nanometers.
No one knows how many workers are exposed to nanomaterials in the U.S. or in the world. One study by Plunkett Research identified 300 companies in the world that deal with nanotech, employing far upwards of 6.4 million people. Another study found over 24,000 U.S. workers whose companies deal just with nanotech. Nano workers assemble automobiles and airplanes, work in pharmaceutical plants, and manufacture materials like coatings and concrete.
Schulte, et al, 2009
The number of different nanomaterials that workers deal with globally is “almost uncountable,” said to Paul Schulte, director of NIOSH’s Education and Information Division. Nanomaterials come in a myriad of combinations of size, shape, solubility, surface coating, and surface charge. (Some are pictured).
While much is unknown, “there is growing evidence for the hazards of nanomaterials,” Schulte said. That evidence comes from three sources: epidemiological studies on humans exposed to air pollution, studies of workers exposed to nanomaterials caused by combustion, and animal research on engineered nanomaterials.
NIOSH has already established guidelines recommending that nano workers take precautions when handling nanomaterials. The institute convened the conference to discuss what else government and industry can do to get ahead of any health and safety issues.
One proposal NIOSH sought input on: setting up a “medical surveillance” system to monitor nano workers’ health.
Medical surveillance, also called occupational health surveillance, is the “ongoing systematic collection, analysis and dissemination of exposure and health data on groups of workers for the purpose of preventing illness and injury,” in the words of NIOSH’s Douglas Trout.
In the context of nanotechnology, that would mean figuring out who nanotech workers are, and monitoring their health – either through collecting data on groups, or by screening individuals.
Melissa Bailey Photo
Dr. Michael Kosnett (pictured), an associate clinical professor of medicine at the University of Colorado Denver, presented a few ideas for how the latter might be done.
Kosnett said while much is unknown, there are two major potential health risks of nano exposure: cardiovascular disease and chronic lung disease.
Screening workers for these outcomes is “possible, but challenging,” he said.
In the pulmonary department, there are problems with some standard tests: chest x‑rays are not sensitive enough to test for one affliction that may face nanotech workers — granulomatous lung disease. Another alternative, spirometry, is also insensitive to that disease, Kosnett said.
What would be better?
One option is high-resolution imaging using CT scans. Exercise oximetry, where you put someone on a bicycle for six minutes and test for a change in the oxygen saturation in the blood, is another promising technique.
Kosnett saw hope in an emerging technology that would be easier and less invasive than other medical tests.
All the worker has to do is blow into a tube. (Pictured is one model, the RTube.) The breath is then cooled, condensed and frozen into what’s called exhaled breath condensate (EBC).
New research has identified biomarkers in the EBC that may be emerging biomarkers for lung disease. These biomarkers – 8‑Isoprostane, an indicator of oxidative stress and TNF-alpha, a cytokine, are two examples – show up in the breath of people with lung disease. (For citations, see here and here.)
More research has to be done before the biomarkers are validated for sensitivity, specificity and positive predictive value. But the technology holds promise as a way to detect lung disease in nanoworkers at an earlier stage than is possible with other tests.
The exhaled breath condensate studies created somewhat of a buzz in the conference auditorium. One man jumped to the microphone and declared the method “exciting.”
Kosnett agreed.
“This is really an exploding area,” he said. Exhaled breath condensate been used to study occupational health fewer than 20 times, he said.
Another questioner expressed concern that the method would create false negatives.
Kosnett emphasized that the medical test is not ready to be used to diagnose individual patients.
“It’s an emerging technology,” he said. “It’s something worth exploring.”
Discussion stirred a plethora of questions: Who would the surveillance target? Should we bank workers’ blood? Who would pay for maintaining a medical database? Some argued medical surveillance would not be useful at this time, because of the wide variety of nanomaterials, the unknown risks, and the difficulty in measuring workers’ exposure to them.
David Kriebel, a professor at the School of Health and Environment at UMass Lowell, capped the day’s proceedings with an impassioned call to action.
“We have asked these workers to enter with us in a huge experiment,” he said. Nanotech companies are telling workers, “we’re going to ask you to work eight hours a day with something that life has never seen before.” He called for creating a watchdog group to monitor the industry with an eye on workers’ health.
As much as the societal benefit of nanotech inventions must be considered, he argued, “We have ethical responsibilities to these workers, too.”