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

MERCURY 331
2. HEALTH EFFECTS
groups) have been used to decrease the absorption rate of methylmercury (Clarkson et al. 1973). The oral
administration of activated charcoal has also been suggested (Gossel and Bricker 1984; Stutz and Janusz
1988). Rapid removal of mercury from the gastrointestinal tract may be indicated in some acute, highdose
situations. In such situations, immediate emesis or gastric lavage has been suggested (Goldfrank et
al. 1990; Haddad and Winchester 1990). Inclusion of salt-poor albumin or sodium formaldehyde
sulfoxylate in the lavage fluid to convert the mercuric ion into the less soluble mercurous ion in the
stomach has also been recommended (Haddad and Winchester 1990). Emesis is contraindicated
following the ingestion of mercuric oxide, presumably because of the risk of damage to the esophagus as
the potentially caustic compound is ejected. A saline cathartic, such as magnesium sulfate, to speed
removal from the gastrointestinal tract has also been recommended unless diarrhea has already begun
(Haddad and Winchester 1990; Stutz and Janusz 1988). Giving CaNa2-EDTA is contraindicated because
it binds poorly to mercury, may be toxic to the kidneys, chelates other essential minerals, and may cause
redistribution of mercury in the body (Gossel and Bricker 1984).
2.10.2 Reducing Body Burden
Since the main source of mercury exposure for the general public is organic mercury in the diet,
minimizing the consumption of mercury-laden fish and shellfish is an effective means of reducing the
body burden. The amount of inhaled mercury vapor from accidental spills of metallic mercury (e.g., from
broken thermometers or electrical switches) can be minimized by informing the general public of the
potential dangers and volatility of liquid mercury, and by prompt and thorough clean-up of liquid mercury
spills.
Following exposure and absorption, metallic mercury is distributed primarily to the kidneys. Elemental
mercury is highly soluble in lipids and easily crosses cell membranes (Gossel and Bricker 1984),
particularly those of the alveoli (Florentine and Sanfilippo 1991). Once in the blood, this form of
mercury can distribute throughout the body, as well as penetrate the blood-brain barrier, thus
accumulating in the brain (Berlin et al. 1969). The body burden half-life of metallic mercury is about
1–2 months (Clarkson 1989). The kidney is also the primary organ of accumulation for compounds of
inorganic mercury, but the liver, spleen, bone marrow, red blood cells, intestine, and respiratory mucosa
are target tissues as well (Haddad and Winchester 1990; Rothstein and Hayes 1964). Inorganic mercury
is excreted primarily through the kidneys; its half-life ranges from 42–60 days (Hursh et al. 1976; Rahola
et al. 1973). As with elemental mercury, organic mercury compounds accumulate throughout the body
(Aberg et al. 1969; Miettinen 1973). Accumulation of organic mercury also occurs in the liver, where it