What is Mercury?
Mercury is a naturally occurring heavy metal. It is unique because
it is liquid at atmospheric temperatures and it uniformly expands
and contracts in response to changes in temperature and pressure.
Mercury occurs naturally and is found in very small amounts
in oceans, rocks and soil. Mercury naturally cycles through the
environment when rocks break down, volcanoes erupt, and soil
decomposes. It then circulates and is distributed throughout the
environment. In its metallic form, mercury is a silvery white liquid
that reflects light like a mirror.
Mercury’s unique properties make it suitable for measuring
temperature and pressure. It has been used in thermometers,
thermostats, barometers, and blood pressure gauges. Its shine made
it desirable for coating mirrors and making mercury glass. Its affinity
for other precious metals made it important in the mining of gold and
silver and making dental amalgam.
Mercury is toxic. It is a hazardous chemical that can cause
irreversible damage to your brain and nervous system. Its production,
transport, and use is now highly regulated. The western world has
found replacements for many of the standard uses of mercury, but mercury is still
a necessary component of fluorescent, neon, and high-intensity light bulbs, silver
dental amalgam and preservatives in vaccines and cosmetics.
How Does Mercury Affect the Environment?
Although mercury is a natural element, the waste and residual contamination from
past use of the metal and the ongoing burning of fossil fuels for energy continue
to emit mercury into the environment. Mercury can become airborne when coal,
oil, wood, or natural gas is burned as fuel or when mercury-containing garbage
is incinerated. Once in the air, mercury can fall to the ground with rain and snow.
This can then contaminate soil, bodies of water, and the creatures living there.
What Are the Human Health Effects of Mercury?
People are most often exposed to mercury through inhalation. Mercury vaporizes
at room temperature, and is both colorless and odorless. Mercury can also be taken
into the body through the skin, mouth, or by eating mercury-contaminated fish (see
Mercury in Fish section below).
Mercury affects the human brain, spinal cord, kidneys, lungs and liver. Symptoms
of short-term exposure to high levels of mercury include nausea, shortness of
breath, fever, muscle aches, skin rash, sore gums, and an elevated white blood cell
count. Symptoms of long-term exposure include tingling sensations in the fingers
and toes, numbness around the mouth, and tremors. Long-term exposure can result
in symptoms that get progressively worse and lead to personality changes, tunnel
vision, stupor, coma, and death.
This publication is issued by the
Oklahoma Department of Environmental
Quality authorized by Scott A. Thompson,
Executive Director. Copies have been
prepared at a cost of $0.212 each. Copies
have been deposited with the publications
clearinghouse of the Oklahoma
Department of Libraries.
(Fact Sheets\LPD\What is Mercury.indd
8/2021)
