Mercury in Medical and Dental Products
Do children's vaccines contain mercury?
All of the routine childhood immunizations are currently available in formulations that do not contain mercury or that contain only trace amounts. In the past, many vaccines contained a preservative called thimerosal, which contains ethyl mercury. But in the late 1990's, NRDC and others successfully pressed for the removal of thimerosal from childhood vaccines. The flu vaccine is the only routine childhood vaccine that still sometimes includes thimerosal. Parents can request the mercury-free version of this vaccine. Some of the combined diphtheria and tetanus vaccines may contain trace residues of thimerosal from the manufacturing process, but the amounts are extremely small.
I have heard that vaccines can cause autism. Is that true?
Medical scientists do not know what causes autism. Some people have speculated that vaccines containing thimerosal may be linked to this disease. Although a few studies have suggested such a link, the best studies so far have not found one. The Institute of Medicine of the National Academies of Science has reviewed the scientific evidence on this topic and concluded that probably no link exists between vaccines and autism. The epidemic of autism in the United States today is extremely serious and more research into possible environmental causes is imperative.
While the causes of autism remain unknown, there is no question that mercury is a neurotoxin which can cause serious harm to the developing nervous system. Children exposed to mercury early in life can develop neurological delays that may appear as subtle learning disabilities. Children's exposure to toxins such as mercury should be limited in every way possible, and the removal of mercury from childhood vaccines was an essential advance. As noted above, flu vaccines may still contain thimerosal but parents can request the mercury-free version.
Do thermometers containing mercury pose a health risk?
Direct exposure to mercury from a broken mercury fever thermometer can be dangerous, particularly for young children. If spills are not cleaned up properly, mercury vapors in the air can cause damage to the lungs, kidneys and brain when inhaled. Also, if a mercury thermometer ends up in a landfill or incinerator, the mercury will enter the environment and can find its way into our food supply through fish. Because of these risks, California and many cities and counties around the country now prohibit the sale of mercury thermometers.
Alternatives such as digital thermometers -- which are inexpensive, accurate, easy to use and less damaging to the environment than mercury thermometers -- are becoming increasingly popular.
What should I do if my mercury thermometer breaks?
Carefully sweep the little silver balls of mercury into a disposable plastic container and seal the container shut. Then take the container to your local household hazardous waste collection facility. Do not flush the mercury down the toilet, vacuum it up or dispose of it in the regular trash. If mercury spills on a carpet or rug, many experts recommend getting rid of these items, since mercury is extremely difficult to remove and will continue to vaporize into the air over time.
How should I dispose of my old mercury thermometer?
Many cities, as well as some hospitals and medical clinics, have programs that allow you to exchange your mercury thermometer for a free, digital replacement. Household hazardous waste collection facilities and many pharmacies also collect and safely dispose of mercury thermometers. For full details, see the blue pages of your phone book and contact your local health department.
Do dental fillings containing mercury pose a health risk?
Recent studies have shown that silver-colored dental fillings, which contain as much as 50 percent mercury by weight, can release mercury vapor -- particularly when they are new or when the wearer chews gum or food. Once inhaled, this vapor can be toxic to the lungs, kidneys, and brain -- particularly of infants and children. Pregnant women, or women planning to become pregnant within the next few months, should avoid getting mercury fillings. Swallowing filling fragments poses less risk of harm because metallic mercury is not as easily absorbed in the stomach and intestines.
Dentists' offices are a major source of mercury pollution in water. To prevent pollution, dentists who use mercury should always install an amalgam separator device in their offices. These devices filter the mercury out of wastewater so that it doesn't contaminate the water supply and eventually accumulate in the fish that we eat.
Should I have my mercury fillings removed?
Most experts agree that it is best to leave existing mercury fillings in place unless they need to be removed for other reasons. During removal, the heat of a dentist's drill can efficiently vaporize the mercury, resulting in significant inhalation of this toxic metal. In addition, the drill can chip out small bits of the filling, which become embedded in cheeks and gums. These chips can then release mercury directly into the body. So removing mercury fillings can actually increase your exposure to mercury.
Are mercury-free fillings available?
Yes. The most popular alternative to mercury fillings is composite fillings (which are often called "porcelain"). But these fillings, which contain a chemical called Bisphenol A, have their own potential health risks. Bisphenol A has been shown to be estrogenic in lab animals and cause disruptions in sexual development in male mice at exposure levels similar to those of people with composite fillings. More scientific research is needed to determine whether these fillings are preferable to mercury fillings. Gold fillings appear to be the safest alternative, but are considerably more expensive. It's best to discuss the benefits and drawbacks of each option with your dentist.
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