2002 - Volume 1 - JEFF. Journal of Engineered Fibers and Fabrics

RESEARCHER’S
TOOLBOX
Banning of Mercury Thermometers
Being “banned in Boston” may be good
(or bad) for a book or a play. However, the
most recent banning in Bean Town has
been the banning of mercury thermometers,
the fever type as well as others containing
mercury. Several other cities, as
well as some state and local governments,
have taken steps to discourage the sale and
use of these thermometers
The reason for this action, of course, is
the concern with mercury contamination
of the environment. The mercury in just
one thermometer can contaminate an 11acre
lake, and broken thermometers could
add some 17 tons of mercury to the U.S.
waste stream annually.
There is no problem if the mercury stays
inside the glass capillary of a thermometer.
When the thermometer is broken and the
mercury is allowed to escape into the environment,
problems can result. If the
escape is inside a structure, the small globule
of mercury can volatilize slowly, raise
and maintain the level of mercury vapor at
a dangerous level.
If released outdoors, the mercury generally
finds its way into streams, rivers and
lakes. In this aqueous environment, metallic
mercury is converted into methylmercury,
which is particularly troublesome, as
this compound can easily enter into the
fish population and thence into the food
cycle of human beings.
This was the cause of “Minimata
Disease” that struck a small fishing town
on Minimata Bay in Japan several years
ago. Discharge of mercury from a nearby
chemical plant that used a mercury compound
as a catalyst resulted in contamination
of the bay, which surprisingly resulted
in the formation of highly toxic
methylmercury and a subsequently dangerous
mercury level in the fish. Because
fish from the bay was a major part of the
diet of the population, many people were
afflicted with what was eventually recognized
as mercury poisoning. Numerous
deaths and disabilities resulted.
Mercury poisoning was also the cause
of “Mad Hatter’s” disease, which in years
past plagued felt hat manufacturers and
those that used mercury chloride to de-hair
animals.
One of the major concerns with mercury
contamination is the effect on small
children and on a growing fetus. This
stems from the fact that the developing
nervous system is especially vulnerable to
mercury toxicity. This has resulted in advisories
about the potential dangers to pregnant
women and children of consuming
fish from some areas and at some times.
In the metallic form, mercury is not
inherently dangerous. However, the liquid
vaporizes at room temperature, giving rise
to mercury vapor which can enter the
Computer Disposal
INJ DEPARTMENTS
human body very easily. If the mercury is
exposed to heat, of course, vaporization is
greatly accelerated and absorption is
increased. Thus, mercury vapor and in
aquatic environments are of prime concern
to humans.
There are several alternatives to mercury
thermometers, and these are becoming
much more common. The digital electronic
thermometer is probably the best
known alternative, and is an excellent substitute
for the mercury version. The alcohol
thermometer (usually shows as a red
liquid) and the galinstan (gallium-indiumtin
liquid) thermometers are also good
alternatives. . In Boston and elsewhere,
area stores are offering digital and other
safe thermometers in exchange for mercury
models.
The primary environmental concern
arising from use of alternative thermometers
relates to the disposal of button cell
batteries used in digital electronic thermometers.
Button cell batteries used in
such thermometers contain significantly
less mercury than in a mercury thermometer
— about 3.5 to 11 milligrams of mercury
per battery (depending on type) versus
approximately 700 milligrams in a
small thermometer. Such button cell bat-
Along with being concerned with mercury from thermometers, researchers
and others must become more concerned with the disposal of computers and
similar electronics equipment.
What do you do with an old computer? The usual practice is to give it to someone
who doesn’t need the latest high-speed unit with a monstrous memory.
However, a computer is eventually discarded. With millions of them being sold
each year, the number ready for discard is rapidly as well.
In years past, there were enterprising individuals that would dissemble an old
computer to salvage parts and other items. Older units used to have gold in the
connectors, a fair amount of copper and other salvageable materials. Some computer
companies are setting up facilities to take in their own outdated units, by
way of showing some environmental responsibility.
Another feature that must be considered is the high levels of potentially toxic
flame retardants that can be released into the air when old computers, TVs,
microwave ovens the like are dismantled. Researchers at Sweden’s Stockholm
University found airborne levels of flame retardants at two to three orders of
magnitude higher than in other work environments, including a circuit board
assembly plant. Very likely the flame retardant agents arise from the use of these
materials in the cabinet especially, but in other components as well.
INJ Spring 2002 5