revised final - Agency for Toxic Substances and Disease Registry ...

MERCURY
1. PUBLIC HEALTH STATEMENT
banned. Up until 1991, phenylmercuric compounds were used as antifungal agents in both interior
and exterior paints, but this use was also banned because mercury vapors were released from these
paints.
Chapter 3 contains more information on the physical and chemical properties of mercury.
Chapter 4 contains more information on the production and use of mercury.
1.2 WHAT HAPPENS TO MERCURY WHEN IT ENTERS THE ENVIRONMENT?
Mercury is a naturally occurring metal found throughout the environment. Mercury enters the
environment as the result of the normal breakdown of minerals in rocks and soil from exposure to
wind and water, and from volcanic activity. Mercury releases from natural sources have remained
relatively constant in recent history, resulting in a steady rise in environmental mercury. Human
activities since the start of the industrial age (e.g., mining, burning of fossil fuels) have resulted in
additional release of mercury to the environment. Estimates of the total annual mercury releases
that result from human activities range from one-third to two-thirds of the total mercury releases.
A major uncertainty in these estimates is the amount of mercury that is released from water and
soils that were previously contaminated by human activities as opposed to new natural releases.
The levels of mercury in the atmosphere (i.e., the air you breathe in the general environment) are
very, very low and do not pose a health risk; however, the steady release of mercury has resulted
in current levels that are three to six times higher than the estimated levels in the preindustrial era
atmosphere.
Approximately 80% of the mercury released from human activities is elemental mercury released
to the air, primarily from fossil fuel combustion, mining, and smelting, and from solid waste
incineration. About 15% of the total is released to the soil from fertilizers, fungicides, and
municipal solid waste (for example, from waste that contains discarded batteries, electrical
switches, or thermometers). An additional 5% is released from industrial wastewater to water in
the environment.
4