System offers breath of relief to workers
August 03, 1998
RICHLAND, Wash. –
When workers believe they have been exposed to dangerous chemicals on the job, they often must provide a sample of blood or urine and wait three weeks or more to learn their fate. A breath-analyzing device developed at the Department of Energy's Pacific Northwest National Laboratory eases the uncertainty by providing immediate results of chemical exposure using a non-invasive technique.
The Exposure-to-Risk Monitoring System determines within minutes the amount and type of chemical a worker has been exposed to and how much of that chemical has found its way inside the person. The system makes its determination by tracking how much of a chemical is exhaled.
"It's ideal for emergency response situations,"said Pacific Northwest staff scientist Karla Thrall. "Workers have peace of mind knowing what happened and whether they should be concerned. Managers know immediately if they need to control the area for environmental risks to prevent further exposure."
Pacific Northwest researchers created the monitoring system by coupling its technology with a commercial mass spectrometer and an exhaled breath analysis device developed by Battelle, which operates Pacific Northwest for DOE.
The system uses physiologically based pharmacokinetic, or PBPK, mathematical models to translate exposure levels into the amount of internal dose received and the resulting health risk. The PBPK model describes how a compound gets into the body, where it goes within the body, how it breaks down and how it leaves the body.
The monitoring system improves on existing industrial hygiene tools in several ways. Its relatively small size -- approximately 70 pounds -- allows it to be used on-site or taken to an emergency situation, such as a chemical spill. The PBPK modeling also considers a person's physiology -- height, weight and body fat -- to determine better how chemicals distribute in individuals.
Pacific Northwest's system offers a more complete evaluation by measuring exhaled breath. The Exposure-to-Risk Monitor can track dosage of compounds that enter the body through ingestion, skin absorption and/or inhalation. Other monitoring systems generally measure exposure from chemicals in the air. And the monitoring system can measure better a person's exposure by simultaneously identifying multiple chemicals.
In addition to emergency response, companies could use the system for long-term monitoring for potential problems by recording daily exposure information for individuals. This allows a company to know if chemical risks are increasing so it can make safety improvements. Also, if a worker claims he or she was exposed to dangerous levels of a chemical a year earlier, the company has scientific evidence to address the claim.
Here's how it works. If, for instance, a worker believes they have been exposed to a chemical, they would breathe into the monitoring system's mouthpiece for one to two minutes. A mass spectrometer then analyzes the breath sample for volatile organic compounds down to concentrations of less than 10 parts per billion. The PBPK system translates the concentrations into dosages for specific organs then estimates the health risk.
Pacific Northwest researchers are pursuing other potential applications for the system, such as drug investigations by law enforcement officers and diagnosing diseases. In the latter case, the monitor could check a patient's breath for abnormally high compounds associated with diseases such as lung cancer and an inflamed pancreas.
A field test earlier this year at the Toxic Substances Control Act Incinerator in Oak Ridge, Tenn., checked workers for exposure to benzene. Final results will be reported later this summer, but preliminary results show workers received exposures lower than what a person would take in filling a gas tank or smoking a cigarette.
The system's usefulness in emergency situations was illustrated during testing at Oak Ridge when a worker was exposed accidentally to fuel oil. The Exposure-to-Risk Monitor immediately determined that levels of benzene in the worker's exhaled breath had increased by 12 parts per billion.
DOE's Office of Worker Health and Safety funded development of the monitoring system's exposure assessment work.
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