Most of today’s parents and grandparents remember having their temperatures taken with glass mercury thermometers. This type of “glass bulb” thermometer has been in use since 1866, when it was invented by Sir Thomas Clifford Allbutt, a British physician. This small, clinical thermometer was a great improvement over the previously used 12-inch instrument that required 20 minutes to measure a patient’s temperature. The mercury thermometer, very accurate and the standard for nearly a century, is still found in most medicine cabinets today.
During the past 30 years, however, an increasing awareness of the dangers of mercury has brought about an array of mercury-free alternatives, most of which are comparable or reasonable in price and readily available. These choices include:
· Glass Galinstan thermometers, which are non-toxic and similar to mercury thermometers in appearance. These can be used for taking oral, rectal, or axillary (armpit) temperatures. Maximum temperature is achieved in approximately three minutes, resulting in a very accurate “definitive” reading, similar to mercury thermometers. Galinstan is a recently FDA approved gallium-indium-tin substance that is considered earth-friendly; if the thermometer is broken, cleanup with soap and water is all that is needed.
· Glass alcohol (dyed) thermometers, non-toxic, similar to Galinstan thermometers, although not as readily available at retail outlets.
· Digital oral or underarm/axillary thermometers, and digital rectal thermometers, powered either by button cell batteries or solar power. Safe choice, accurate as long as the batteries are not old, although a “presumptive” reading is given, which is not considered as accurate as a “definitive” reading. Batteries contain mercury, so there is still the problem of environmental pollution upon discard, however, they contain much less mercury and it is less likely to be released or emitted into the atmosphere compared to an intact glass mercury thermometer that breaks in a landfill or is incinerated. Digitals include bendable, 30-second, 5-second, and talking models. Disposable probe covers are needed.
· Digital pacifier thermometers, convenient for taking infant’s temperature if he or she takes a pacifier (some don’t, of course). Also, not considered very accurate; a reading will be lower than an actual core body temperature.
· Forehead thermometer strips, which are liquid crystal strips placed on the forehead. While inexpensive, convenient, and comfortable for the patient, these thermometers are not very durable (although they are supposed to be reusable) nor are they very accurate. Should be used for quick screenings only; readings are usually lower than actual core body temperature.
· Digital infrared ear thermometer, considered by many to be the easiest thermometer to use, especially with small children. They measure the temperature in the ear canal within one to five seconds, depending upon the model. Still fairly expensive, and not necessarily “non-invasive” or comfortable for all children; especially children who have had ear aches or ear pain. If positioned incorrectly, they can miss a fever, or readings can be inaccurate. Some models require disposable probes.
· Temporal artery thermometer, a new instrument that “captures naturally emitted heat from the skin” over the temporal artery as it is stroked gently across the forehead. Considered at least as accurate as a definitive rectal temperature reading, non-invasive, and extremely comfortable, especially for infants and children. The device has a large LED display, and needs no probe (although disposable probes are available).
With the vast number of choices now available, it makes sense for consumers to replace their old glass mercury thermometers with safer mercury-free thermometers. Be sure to dispose of mercury thermometers safely at either a hazardous waste collection facility, or a local thermometer exchange program in your area. Do not throw mercury thermometers in the trash. If they are broken or incinerated, the mercury will make its way into the environment causing increased mercury pollution and poisoning.
