Ask A Scientist© Chemistry Archive

2001345

name         mithat
status       student
age          20s
Question -   I know that organic mercury is poisonous and is taken
up easily by body, but how is inorganic mercury taken up by the body?
Is it harmful?
------------------------------------------------
Water soluble compounds of mercury, as a class, are considered highly
toxic and should be handled with respect and care. Particular mercury
compounds, I'm thinking specifically of HgS, the sulfide, is extremely
insoluble in water but I don't know what would happen at the pH of the
stomach which is anywhere from about 2 to 4. It may dissolve, and be toxic.
Remember, when considering toxicity you have to keep in mind not just the
mouth but all possible ports of entry.

Metallic mercury is toxic. It is absorbed through the skin. Breaks up into
fine particles to form a mist that can be inhaled. It also has a vapor
pressure of ~0.001 torr, which while small is large enough to be toxic if
the person is chronically exposed.

It is hard to justify why you can still find mercury thermometers in
pharmacies, but they are.

The short answer: Don't mess with mercury unless you know exactly what you
are doing.

Vince Calder
=======================================================
The Center for Disease Control web site regarding Occupational Health
Guidelines http://www.cdc.gov/niosh/81-123.html? states that inorganic
mercury may enter the body through skin absorption.  I've verified this
with the Hawley's Condensed Chemical Dictionary, 12th edition.  I hope
this documentation puts Mr. Michelsons concern to rest.

Dan Poulos
=========================================================
According to the Fluka Material Safety Data Sheet for mercury, it is toxic
upon skin exposure.  It is hard to imagine how this could be unless it is
absorbed through the skin.  The Merck Index entry on mercury indicates that
it is readily absorbed through intact skin.

Metallic mercury has a low but measurable vapor pressure at room
temperature.  It probably passes through the skin in vapor form.

That said, a single exposure to mercury on the skin will probably not cause
harm.  Ingestion of mercury has even been reported without toxic effects.
However, bear in mind that mercury is a cumulative poison.  Repeated
exposure IS very dangerous.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois
=========================================================