Nov. 10, 2011
Mercury is a naturally occurring element found in trace amounts in rocks, minerals, soils and the atmosphere. It is the only heavy metal that is liquid at room temperature. In the elemental form, mercury can vaporize with increasing temperature.
When mercury is exposed to the air, or heated, it is released into the atmosphere. Rainfall or snowmelt then carries the mercury into lakes and waterways. Once in the water, bacteria convert elemental mercury to methyl mercury. In this form, mercury accumulates in the tissues of some fish. When humans or other animals eat the fish, the mercury becomes a health risk. Mercury poisoning attacks the central nervous system in all humans. Unborn children and children under the age of 12 are at the highest risk, because their nervous system is still developing.
The greatest risk of exposure from elemental mercury in products such as fever thermometers is improper handling and disposal of spilled mercury. Mercury volatiles quickly and is easily inhaled. Improper clean up with a vacuum, paintbrush or household cleaner increases exposure.
Indoor air may be contaminated by mercury vapor from a broken fever thermometer, or other products that have gone unnoticed, or improperly cleaned up. At a high level, mercury can cause damage to the central nervous system, tremors, inability to walk, convulsions and even death.
A small spill is essentially the amount of mercury found in a fever thermometer. Metallic mercury is liquid at room temperature and has no odor, but some of the metal will evaporate into the air and can be carried long distances. Because mercury is toxic when inhaled, you must be careful when handling and disposing of all items that contain metallic mercury. If you break a thermometer, do not panic. The amount of mercury contained in an oral thermometer is small and does not present an immediate threat to human health.
However, if it is not properly cleaned up and disposed of, it may present a health risk over time, particularly to children less than 12 years old and pregnant women.
Source: Missouri Natural Resources www.dnr.mo.gov/env/mercury