One way tetrachloroethylene (perc) may enter
the body is by inhalation of contaminated air into the lungs. Although
this compound is rapidly absorbed by the lungs, the amount that
is absorbed from the lungs into the bloodstream is influenced by
how quickly a person is breathing (inhalation rate), the amount
of chemical in the air, how long the person is exposed, the person's
body mass and degree of physical activity while being exposed (NYS
1996; ATSDR, 1996b).
Studies with human volunteers indicate that
absorption of tetrachloroethylene vapors from the air across the
lungs may be greatest during the first few minutes of exposure.
Perc absorbed into the blood stream is transported throughout the
body and may be temporarily stored (accumulated) in fat tissue and
slowly re-released to the blood stream over a period of several
days. Absorbed perc can cross the blood-brain and placental-fetus
barriers and has been found in fat rich tissues such as the brain,
liver and breast milk (NYS, 1996).
The majority of perc absorbed from the lungs
into the blood stream leaves the body unchanged in air exhaled from
the lungs (EM, 1995). A small percentage of perc that is absorbed
into the blood stream is broken down into other compounds (metabolites)
in the liver (EM, 1995; ATSDR, 1996b). One metabolite in particular,
trichloroacetic acid, is thought to be associated with some of the
adverse health effects noted with prolonged inhalation of elevated
levels of perc (ATSDR, 1996b). These metabolites leave the body
in the urine. Experimental studies indicate that, once exposure
has stopped, total elimination from the body may take a few days
to a few weeks, depending on the amount of perc that has accumulated
in body tissues.
Brief inhalation of large amounts of tetrachloroethylene
can adversely effect the central nervous system and result in dizziness,
headache, sleepiness, confusion, nausea, difficulty in speaking
and walking, unconsciousness and, in extreme instances, death (ATSDR,
1996b). The mucous lining of the eyes, nose and throat may also
become irritated (EM, 1995).
Recovery from the adverse central nervous system
effects associated with inhalation exposure to perc vapors, in some
cases even moderate term exposures, is possible once exposure has
stopped (EM, 1995). However, the potential effects of long-term
inhalation of relatively low levels of perc vapors are not currently
known (ATSDR, 1996b).
Some liver and kidney effects may be associated
with inhalation of elevated levels of perc. One instance of a reversible
adverse cardiac effect associated with inhalation of tetrachloroethylene
vapors is noted in the literature.
Limited studies of women exposed to elevated
levels of perc in the work place, in a mix of other volatile chemicals,
indicate that such exposure may effect the reproductive system and
perhaps be related to an increased risk of spontaneous abortion
(miscarriage) (ATSDR, 1996b). Because exposure was to more than
one chemical at a time, it is not known which chemical or combination
of chemicals may be responsible for the health effects noted.
Repeated or prolonged dermal contact with perc
can cause skin irritation (ATSDR, 1996b). Potential health effects
that may be associated with long term consumption of food and/or
drink containing low levels of tetrachloroethylene are not known
Long term experimental studies with laboratory
animals exposed to very high levels of perc vapors have noted skin,
liver, kidney, cardiac effects and in some cases liver and kidney
cancer. Not all such effects have been noted in people who have
been exposed to tetrachloroethylene at much lower levels.
Tetrachloroethylene has been classified as Group
2A: Probably Carcinogenic to Humans by the International Agency
for Research on Cancer and is generally considered to be an animal
carcinogen and probable human carcinogen by the United States Environmental
to Air Toxics Program Page
Last Updated: 1/31/03