J. T. A. Ely Ph.D.
Radiation Studies 351650
University of Washington, Seattle, Washington 98195 USA
Bulletin of Environmental Contamination and Toxicology
(2001). Vol. 67, pages 800-806
Micromercurialism (MM) is a term coined by the German
chemist Professor A. Stock in the 1920's and widely used
to denote chronic intoxication from long term exposure to
low levels of Hg vapor. He also demonstrated (in
himself) that MM can be caused by dental amalgams.
Stock stimulated a wave of scientific interest in MM in
Germany and Russia. These two countries adopted the
lowest tolerable work place Hg vapor levels in the world,
1 and 10 µg/m3, respectively (Patterson et
al., 1985; Gerstner and Huff 1977). MM differs in
many respects from generally recognized acute form of Hg
intoxication. These differences which were recently
elucidated in the Bulletin (Ely et al., 1999) are
responsible for almost universal failure of physicians to
diagnose MM. As explained there, in order to make
this diagnosis, urine Hg must be measured in µg/day
instead of µg/L because of a highly variable polyuria
common in MM. More importantly, "retention
toxicity" must be understood. This latter
effect, first reported by Public Health Service
investigators (Neal and Jones 1938) is an inverse
relationship in MM between degree of intoxication and
urine Hg content; i.e., the most intoxicated subjects
excrete the least Hg. This, of course, is the reason
their intoxication continues to worsen until the exposure
is terminated. Because of Hg's extreme toxicity as
an enzyme activator (Web 1963), it appears plausible that
in subjects with long-term chronic exposure, Hg has
diabled the enzymes involved in Hg excretion. This
not only results in undetectable or extremely low (<5
µg/day) urine Hg, but also causes blood levels to rise
resulting in diffusion of Hg to bone storage.
It has long been known from x-ray fluorescence studies
that persons with chronic exposure such as dentists, have
elevated skeletal Hg stores (Bloch and Shapiro 1981), and
low urine Hg (Neal and Jones 1938). This is
mistakenly interpreted today almost universally as
evidence of low intoxication attributed to adequacy of
dental clinic precautionary measures. Also, in old
age, osteoporosis may accelerate Hg release to a rate much
above that corresponding to the 20 year excretion
half-time estimated by Sugita (1978). As a result of
these complexities, there is almost no awareness of the
degree of Hg intoxication in the US today or its possible
impact on the incidence of Alzheimer's disease (AD).
Two different types of radiation techniques, neutron
activation analysis and photolabelling, were used by two
different groups of investigators to compare Hg in brains
of AD and control cadavers (Thompson et al. 1988;
Pendergrass and Haley 1997). Oliveri et al. (2000)
used an in vitro model system (neuroblastoma cells) to
investigate the effects of inorganic mercury (HgCl2) on
several central nervous system variables including tubulin
This paper seeks to focus attention on widely ignored
features of micromercurialism from amalgam. These
features already make Hg one of the two leading causes of
Alzheimer's disease incidence and threaten to greatly
increase this tragic toll.
Research Papers from the Laboratory of Dr. J. T. A. Ely
Method for measuring mercury release
from dental amalgam.
Krone CA, Ely JT, Thoreson J.
Applied Research Institute, Post Office Box 1925,
Palmerston North, New Zealand.
Bull Environ Contam Toxicol 2002 Feb;68(2):180-6
Risk factors for parenteral
intoxication by mercury from dental amalgam.
Radiation Studies 351650, University of Washington,
Seattle, WA 98195, USA.
Bull Environ Contam Toxicol 2001 Sep;67(3):309-16
Urine mercury in micromercurialism:
bimodal distribution and diagnostic implications.
Ely JT, Fudenberg HH, Muirhead RJ, LaMarche MG,
Krone CA, Buscher D, Stern EA.
Radiation Studies, Box 351650, University of
Washington, Seattle, WA 98195, USA.
Bull Environ Contam Toxicol 1999 Nov;63(5):553-9