Geoscience Reference
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phosphatizing systems. TCE is used in the textile industry as a carrier solvent for
spotting fluids and as a solvent in waterless preparation dying and finishing
operations (Mertens 2000 ; Doherty 2000a ).
TCE is now a common contaminant at hazardous waste sites and many federal
facilities in the USA. TCE has been identified in at least 1,500 hazardous waste
sites regulated under Superfund or the Resource Conservation and Recovery Act
(EPA 2005 ). TCE can enter surface waters via direct discharges and groundwater
through leaching from disposal operations and Superfund sites; the maximum
contaminant level for TCE in drinking water is 5 ppb. TCE can be released to
indoor air from use of consumer products that contain it, vapor intrusion through
underground walls and floors, and volatilization from the water supply.
On acute exposure, TCE is considered toxic, primarily because of its anesthetic
effect on the central nervous system. Exposure to high vapor concentrations is
likely to cause headache, vertigo, tremors, nausea and vomiting, fatigue, intoxi-
cation, unconsciousness, and even death. Ingestion of large amounts of TCE may
cause liver damage, kidney malfunction, cardiac arrhythmia, and coma (Mertens
2000 ; EPA 2000b ). TCE is anticipated to be a human carcinogen, based on limited
studies on humans and evidence from studies of animals (NTP 2002 ). Studies have
found that occupational exposures to TCE are associated with excess in liver
cancer, non-Hodgkin's lymphoma, prostate cancer, and multiple myeloma, with
the strongest evidence for the first three cancers (Wartenberg et al. 2000 ).
PCE was first prepared in 1821, but industrial production of PCE reportedly
began in the first decade of the twentieth century (Gerhartz 1986 ); significant use
began only about 100 years after its discovery (Doherty 2000b ). The main use of
PCE is in the dry-cleaning industry. It is also used as a feedstock for chloro-
fluorocarbon production, for metal cleaning, as a transformer insulating fluid, in
chemical masking formulations, and as a process solvent for desulfurizing coal
(Hickman 2000 ).
Overexposure to tetrachloroethylene by inhalation affects the CNS and the
liver. Dizziness, headache, confusion, nausea, and eye and mucous tissue irritation
occur during prolonged exposure to vapor concentrations of 200 ppm (Rowe et al.
1952 ). These effects are intensified and include lack of coordination and drunk-
enness at concentrations in excess of 600 ppm. At concentrations in excess of
1,000 ppm, anesthetic and respiratory depression effects can cause unconscious-
ness and death (Hickman 2000 ).
PCE inhalation may affect the CNS and the liver. At higher concentrations, the
effects become more pronounced, and at high concentrations, PCE was used as an
anesthetic substance, which also can cause depression, difficulty in speaking and
walking, respiratory system damage, unconsciousness, and death (Hickman 2000 ).
The International Agency for Research on Cancer determined that PCE probably is
carcinogenic to humans. Results of animal studies, conducted with amounts much
higher than those to which most people are exposed, show that tetrachloroethylene
can cause liver and kidney damage and liver and kidney cancers, even though the
relevance to people is unclear (ATSDR 2006a ).
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