Mercury Poisoning
What is it?
How can you limit your exposure to mercury?
Mercury poisoning is the ill
effect, primarily on the human nervous system, due to over-exposure of
mercury. Survivors of acute poisoning or persons chronically exposed to
inorganic mercury might develop neurologic, dermatologic, and renal
manifestations that include tremor and neuropsychiatric disturbances
such as memory loss, irritability or depression. These personality
changes were noted in the 19th century “mad hatters” who suffered from
mercury poisoning after exposure to mercury in the felting process, when
mercury was rubbed into cloth to preserve it.
Sources of exposure:
Mercury is a naturally occurring
metallic element that is extremely toxic to the brain, kidneys, and
developing fetus. Mercury is released into the environment from mining
ore deposits, emissions from coal-burning power plants, automobile
emissions and disposal of industrial wastes. Once it enters water
supplies, mercury is converted to an organic toxin called methylmercury
that accumulates in the tissues of larger fish.
Other sources of exposure to mercury include:
- Breathing vapors in the air from spills,
incinerators, and industries that burn mercury-containing fuels.
- Release of mercury from dental work and medical
treatments.
- Breathing contaminated workplace air or skin
contact during use in the workplace (dental, health services,
chemical, and other industries that use mercury).
- Practicing rituals that include mercury.
Three chemical forms of mercury:
Mercury exists in three chemical forms, each with specific effects
on human health.
- Methylmercury
Methylmercury can cause impaired neurological development in
fetuses, infants, and children. Methylmercury exposure in the womb
can occur from a mother’s consumption of fish and shellfish that
contain methylmercury which can affect a baby’s growing brain and
nervous system. Cognitive thinking, memory, attention, language, and
fine motor and visual spatial skills have been adversely affected in
children exposed to methylmercury in the womb. The vulnerable fetus
may be born with severe disabilities to mothers who may or may not
have exhibited symptoms of nervous system damage.
- Elemental mercury
Elemental (metallic) mercury primarily causes health effects when it
is breathed as a vapor and absorbed through the lungs. These
exposures can occur when elemental mercury is spilled or products
that contain elemental mercury break and expose mercury to the air
especially in poorly-ventilated indoor spaces. Inhalation problems
usually result from a large one-time exposure or through long-time
exposure (usually work-related). Symptoms include tremors, emotional
changes (e.g., mood swings, irritability, and nervousness),
insomnia, neuromuscular changes (such as weakness, muscle atrophy,
twitching), headaches, and changes in cognitive function. High
levels of elemental mercury exposure my result in kidney damage,
respiratory failure and death.
Sources of elemental mercury in the home include broken
thermometers, broken fluorescent light bulbs, dental amalgam
fillings, and mercury containing latex paint. A small one-time
exposure is not likely to cause problems.
- Other mercury compounds (inorganic and organic)
Inorganic mercury compounds are known as “mercuric salts” such as
mercuric chloride, mercuric iodide or mercuric sulfide. High
exposures to inorganic mercury may result in damage to the
gastrointestinal (GI) tract, the nervous system, and the kidneys.
Some folk medicines from outside the United States such as calomel
contain high amounts of mercury.
Organic mercury compounds are found in a variety of products used
medically as fungicides and antibacterials. The most common organic
mercury compound in the home is mercurochrome and merthiolate, two
common antiseptics.
Both inorganic and organic mercury compounds are absorbed through
the GI tract, but organic mercury compounds are more readily
absorbed via ingestion than inorganic mercury compounds. Symptoms of
high exposure to inorganic mercury include skin rash and dermatitis,
mood swings, memory loss, mental disturbances, and muscle weakness.
Health wise, the primary concern regarding mercury relates to fish
consumption. This chart provides some guidelines to follow:
How is mercury poisoning diagnosed and treated?
Mercury poisoning can be diagnosed by special blood and urine tests.
It is important not to eat any seafood for at least 30 hours before
testing as this will cause misleading high levels. If, after proper
testing, mercury levels are high, there is treatment. Medication is
available that will help bind the mercury and increase elimination.
Contact your physician to determine if testing is right for you.
Websites with information on mercury:
From the Palm Beach County Health Dept.
Epidemiology & Disease Control.
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