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

MERCURY
2. HEALTH EFFECTS
ischemic heart and cerebrovascular disease (Barregard et al. 1990). These studies are limited, however,
because exposure to other chemicals may have contributed to the effects observed, exposure levels may
have been estimated from only a few actual determinations, and other risk factors were not consistently
considered.
Significant increases in systolic blood pressure and diastolic blood pressure were found in volunteers with
dental amalgam containing mercury when compared to a control group (matched for age and sex) that had
no amalgam fillings (Siblerud 1990). However, the length of time that the individuals had the dental
amalgams was not reported. Furthermore, the blood pressure levels of the amalgam group were closer than
those of the nonamalgam group to "normal" blood pressure levels reported for the general population. The
authors suggested that the populations from which such normal values are drawn are likely to include many
people with amalgam dental fillings, but without additional data to determine which control group would
best represent “normal,” these results have limited use.
In animals, cardiovascular effects were noted following inhalation exposure to mercury vapor. Marked
cellular degeneration with some necrosis of heart tissue was observed in rabbits following acute intermittent
exposure to 28.8 mg/m 3 metallic mercury vapor for periods ranging from 4 to 30 hours (Ashe et al. 1953).
Mild-to-moderate pathological changes (unspecified) were seen for 1–4-hour exposures. Exposures to
lower concentrations (0.86–6 mg/m3 ) of mercury vapor for periods ranging from 2 to 12 weeks also resulted
in mild-to-moderate pathological changes (unspecified) in the hearts of rabbits. The usefulness of these
results is limited because the study did not specify the pathological changes nor distinguish between
primary and secondary effects (i.e., pathological changes secondary to induced shock).
Organic Mercury. Only two case histories were located regarding cardiovascular effects in persons
exposed by inhalation to organic mercury compounds. No cardiovascular effects were reported in four men
hospitalized for neurological symptoms after inhaling an unspecified concentration of methylmercury dust
for at least several months (Hunter et al. 1940). Elevated blood pressure was reported in two men exposed
occupationally to methylmercury compounds (dose not known) (Hook et al. 1954).
No studies were located regarding cardiovascular effects in animals after inhalation exposure to organic
mercury.
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