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Mercury
Thermometers: Are they really a hazard?
By: Dr.
Stefanie Kelley
December 2002/January 2003
Have you wondered
if all the commotion on banning of mercury thermometers is really valid?
Mercury, also known as cinnabar, is a silvery-white liquid that flows
at room temperature. It has been used since the 16th century B.C. because
of the ease with which it bonds to metals. It also has many useful applications
in the modern world because of its ability to easily conduct electricity.
Mercury’s most dangerous attribute is its capacity to vaporize and
form a hazardous gas. It can remain in the atmosphere for up to a year,
posing a serious health risk to many forms of life, including humans.
Mercury can also contaminate the environment through wastewater, particularly
through industrial runoff. It cannot be broken down into less harmful
compounds and builds up in living organisms that have been exposed to
it. Once it enters a water supply, bioaccumulation can occur in aquatic
life forms. The marine food chain has been hard hit by mercury pollution
and, in turn, the impact has impacted food supplies. As mercury collects
in the liver, kidneys, brain and blood, it can cause hepatic, renal, and
neurological health problems. The Environmental Protection Agency banned
the use of mercury in paints and pesticides in the early 1990’s,
but Mercury is still used in numerous products including:
- Barometers
- Thermometers
- Dental amalgams
- Dry-cell batteries
- Fluorescent light
bulbs
- Manometers
- Medicines
It is also used currently
in a variety of manufacturing processes, including metal plating, photography,
tanning and dyeing. In the nineteenth century, it was used in the manufacturing
of felt hats, which may account for the origination of the expression
“mad as a hatter.”
But the question remains, does a broken fever thermometer really pose
a health risk to the public? Thermometer manufacturer Becton Dickenson
estimates that 4.3 tons of mercury is contained in the thermometers sold
each year. This represents only 1% of the total mercury use in the United
States. However, failure to properly dispose of a broken thermometer can
expose people to health risks. Because it vaporizes so easily, inhalation
poses the biggest threat to humans. Some people may not even know that
a mercury thermometer has been broken. The mercury from a broken thermometer
may seep into carpet and continuously vaporize, thus contaminating immediate
surroundings. It is likely that some individuals might try to clean up
the mercury beads with a vacuum cleaner, only to further expand the airborne
mercury toxins. If the mercury beads are collected and disposed of in
household garbage, the mercury-contaminated refuse may be incinerated
and airborne toxins could be released into the environment.
When a mercury thermometer has been broken, several important procedures
should be followed to limit human exposure and to protect the environment.
- Increase ventilation
in the contaminated room with outside air and close it off from the
rest of the building. Use a fan to circulate the air for at least an
hour.
- Collect the mercury
with an eyedropper or scoop up the beads with a piece of heavy paper
(playing cards or index cards work well).
- Place the mercury
contaminated utensils (dropper or paper) and any broken glass in a plastic
zipper bag. Triple bag the waste. Place the bagged mercury waste in
a sealable plastic container.
- Call your local
health department for the nearest approved mercury disposal location
or dispose of the plastic container in accordance with state and local
requirements.
When cleaning a mercury
spill:
- Do NOT use household
cleaning products to clean the spill, specifically products containing
ammonia or chlorine. A toxic gas may be produced.
- Do NOT use a broom
or paintbrush. The mercury will break into smaller beads and spread
further.
- Do NOT use a vacuum,
shop vacuum, or hand-held vacuum. The mercury will further release into
the air.
Federal, state and municipal
legislators are trying to help protect the environment and the public from
mercury contamination. The United States Environmental Protection Agency
has attempted to regulate the release of mercury into the environment and
to monitor mercury levels in fish. Forty states have issued fish consumption
advisories due to mercury contamination of their lakes, streams, and rivers.
Several cities, including Ann Arbor, Duluth, San Francisco, and Boston have
even banned the sale of mercury thermometers.
So what should a practicing health care professional do with a mercury thermometer
and what should be used in its place in order to measure fever? First, check
local laws to find out about bans on mercury thermometers or possible thermometer
swap programs*. Also, contact your health agencies for mercury thermometer
collection policies. There are several thermometers, which do not contain
mercury and still accurately measure fever. Digital electronic fever thermometers
are readily available. Glass alcohol thermometers and glass gallium-indium-tin
(galinstan) thermometers have been approved by the Food and Drug Administration.
Flexible forehead strip thermometers are another option and are generally
inexpensive. Ear canal thermometers are also a possibility, but are more
costly. The accuracy in measuring fever can vary due to the practioneer’s
technique and the patient’s cooperation. Research has reported no
clinically significant difference in readings from oral digital thermometers
and ear canal thermometers (Gilbert, Barton, & Counsell, 2002). When
purchasing a thermometer, consider the cost, ease of use, and environmental
impact. The effects of mercury on the public and the environment may result
in the mercury thermometer ultimately becoming a nostalgic image of a bygone
era, perhaps not unlike that of the hatter.
The US Environmental Protection Agency has many resources on mercury at
www.epa.gov.
Other Resources:
Gilbert, M., Barton, A.J., & Counsell, C.M. (2002) Comparison of oral
and tympanic temperatures in adult surgical patients. Applications in Nursing
Research, 15 (1), 42-47.
Michigan State University Office of Radiation, Chemical and Biological Safety.
Mercury:
A Fact Sheet for Health Professionals.
*Welch Allyn offers free mercury disposal that will safely dispose of your
existing mercury sphygmomanometers as part of a facility-wide conversion
program. For more information, contact Welch Allyn at (888) 359-2394 or
visit the EPA website at http://www.epa.gov/seahome/mercury/src/outmerc.htm
Mercury Elimination
– a Healthcare White Paper*
States Mercury
Products Legislation*
*Adobe
Acrobat is required to view or print the above documents. Click the icon
below to download a free copy.
School Health Corporation offers many non-mercury thermometer alternatives:
Tempa-Dot
Single-Use Thermometers
SureTemp
Thermometer Model 679
NexTemp
Single-Use Thermometers
Electronic
Digital Thermometer
ThermoScan
Pro 3000 Thermometer
Stefanie J. Kelley, ND, RN, CS has been in
the nursing field for over 10 years. She has clinical expertise in general
pediatrics and pediatric hematology, oncology, and bone marrow transplantation.
As a family nurse practitioner she has advanced practice expertise in internal
medicine, urban health care, and general pediatrics. As a faculty member
at Texas A&M University and Case Western Reserve University, she has
taught in the undergraduate and graduate didactic and clinical portions
of nursing. Dr. Kelley's interest in web-based instruction and health care
has been a part of her academic, clinical, and research practice.
Dr. Kelley welcomes your comments about her article or suggestons for future
topics. She can be emailed at sjkelley6@yahoo.com.
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