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

MERCURY 322
2. HEALTH EFFECTS
mercury was expressed by the equation 10 log (acceleration)=G0.888 + 0.0059 (urine mercury) (r=0.39,
p50 µg/g creatinine can cause a dose-related loss of color vision.
An association between urine mercury levels and performance on memory tests and verbal intelligence
tests has been established. Abnormal results on memory tests were reported for 9 workers exposed to
mercury in the production of thermometers; urinary mercury excretion levels were 7–1,101 µg/24 hours
(Vroom and Greer 1972). The short-term memory span of 26 workers was examined by Smith et al.
(1983) and found to decrease with increasing urine mercury levels. The range of mercury found in the
urine of these workers was 0–510 µg/L. A significant linear relationship was reported between subjects'
50% memory threshold spans and 12-month urinary mercury concentrations. Disturbances on tests of
verbal intelligence and memory were more frequent among individuals with mercury blood levels above
1.5 µg/100 mL and mercury urine levels above 56 µg/L in 36 male chloralkali workers (Piikivi et al.
1984).
Potential biomarkers for the autoimmune effects of mercury include measurement of antiglomerular
basement membrane antibodies, anti-DNA antibodies, serum IgE complexes, and total IgE (Cardenas et al.
1993). Elevated IgE, antiglomerular basement membrane antibodies, and anti-DNA antibodies have been
observed in a few persons with exposure to mercury from dental amalgams (Anneroth et al. 1992). Other
individuals have also been shown to have elevated anti-DNA or antiglomerular basement membrane
antibodies (Cardenas et al. 1993; Langworth et al. 1992b).
Recent data regarding the action of low-level mercury exposure on receptors and signal transduction
pathways in peripheral lymphocytes suggest potential applications of certain surrogate markers in
mechanistic studies of neurotoxicity and, possibly, in assessing early biochemical effects of neurotoxicants
in humans (Manzo et al. 1995). Additional biomarkers for effects on the immune, renal, hepatic, and
neurological systems are presented in the CDC/ATSDR (1990) and OTA (1990) reports. See Section 2.2
for a more detailed discussion of the effects caused by mercury.