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

MERCURY 451
5. POTENTIAL FOR HUMAN EXPOSURE
to chronic exposure to mercury, but the relative contribution of recent exposures to mercury levels in these
media, in comparison to releases of mercury stored in tissues as a result of earlier exposures, is not well
understood (EPA 1984b) (see Section 2.5).
Mercury exposure also may result from the transport of mercury to a workers' home on contaminated
clothing and shoes (ATSDR 1990; Hudson et al. 1987; Zirschky 1990). Increased exposure to mercury has
been reported in children of workers who are occupationally exposed (Hudson et al. 1987). The population
of children at highest risk are those whose parents work in facilities that use mercury, but where no
protective uniforms or footgear are used. The mercury is thought to be transferred to the workers' homes in
their clothing and shoes. While prevention of employee-transported contamination to their homes is
preferred, cleaning the homes of workers occupationally exposed to mercury is also effective in reducing
exposure for family members (Zirschky 1990). In an exposure study of families of workers at a chloralkali
plant in Charleston, Tennessee, mercury levels in the air of the workers' homes averaged 0.92 µg/m 3
(ATSDR 1990).
The use of fluorescent tube compactors by industrial facilities may also expose those operating the
compactors and workers in adjacent areas to increased levels of mercury vapor if proper filters, scrubbing
devices, and ventilation are not used (Kirschner et al. 1988).
Dentists and other dental professionals may have greater exposure to mercury as a result of preparing and
applying dental amalgams (Ayyadurai and Krishnashamy 1988; Skare et al. 1990). Nylander et al. (1989)
sampled pituitary gland tissue from autopsies of 8 dental staff and 27 control individuals in Sweden. These
authors reported median mercury concentrations of 815 µg/kg (ppb) wet weight (range, 135–4,040 µg/kg) in
pituitary tissue of dental staff (7 dentists and 1 dental assistant), as compared to a median of 23 µg/kg (wet
weight) in 27 individuals from the general population. None of the dental staff had been working
immediately prior to their deaths, and in several cases, more than a decade had passed since the cessation of
their clinical work. The number of amalgams did not correlate to pituitary gland concentrations in the
controls. However, if two of the controls with the highest mercury concentrations were excluded (there was
some evidence that these individuals had received occupational exposures), then the correlation was
significant (p