Trichloroethylene - Health Effects of Chronic / Repeated Exposure (Human)

Inhalation

Central nervous system toxicity is the main effect following chronic exposure to trichloroethylene. Occupational studies have consistently reported central nervous system effects, including fatigue, vertigo, dizziness, headaches and impaired ability to concentrate [1, 3]. Other neurological effects include mood swings, trigeminal neuropathy, cranial nerve VII damage, impaired acoustic-motor function and psychotic behaviour with impaired cognitive function [1].

Several occupational studies have reported liver effects, including liver enlargement and increases in serum liver enzyme levels in workers exposed to unspecified concentrations of trichloroethylene. Other studies have not reported any adverse effects on the liver [1, 3]. Altered renal function (increased N-acetyl-β-D-glucosaminidase and urinary proteins) has been noted in workers exposed to trichloroethylene and other chemicals in the workplace [1].

Occupational exposure to trichloroethylene at concentrations that caused neurological effects resulted in  body weight loss in some workers [1].

Ingestion

There are limited data available regarding the health effects of chronic oral exposure to trichloroethylene.

A number of studies have attempted to assess the adverse health effects associated with the consumption of drinking water contaminated with trichloroethylene. Adverse health effects reported include cardiac, gastrointestinal, liver and immunological effects. Limitations of the studies include exposure to other contaminants; therefore the results should be considered inconclusive [1, 3].

Dermal exposure

Repeated contact with trichloroethylene may lead to the development of erythematous, exudative, vesicular, eczematous or exfoliative dermatitis, due to a defatting action on the skin [2].

Genotoxicity

There are limited data available regarding the genotoxic effects of exposure to trichloroethylene in humans. Data from cytogenetic studies using peripheral lymphocytes of workers exposed to trichloroethylene were inconclusive  [1, 3, 8].

Carcinogenicity

The International Agency for Research on Cancer (IARC) considered three cohort studies to be particularly relevant for the evaluation of trichloroethylene. Two of the studies conducted in Sweden and Finland involved individuals who had been monitored for exposure to trichloroethylene by measurement of the metabolite trichloroacetic acid in urine. The third study, conducted in the United States, included workers, some of who were exposed to other solvents. The results from the three studies consistently indicated a significant excess relative risk for cancer of the liver and biliary tract combined. There was also a small non-significant excess in cancer of the liver. Results from the three studies indicated a modest excess relative risk for non-Hodgkin's lymphoma [8].

IARC concluded that there is limited evidence in humans for the carcinogenicity of trichloroethylene but that there is sufficient evidence in experimental animals for the carcinogenicity of trichloroethylene. It is classified as probably carcinogenic to humans (Group 2A) [8].

Reproductive and developmental toxicity

There are very limited data available regarding the reproductive and developmental toxicity of trichloroethylene in humans. Three Finish reproductive occupational studies did not report an increased incidence of spontaneous abortion or congenital malformations in the children of mothers exposed to trichloroethylene in the workplace. However, it is not possible to draw any definite conclusions from these studies, due to the poor characterisation of exposure levels [3].

Acute/Single Exposure (Animal)       Chronic/Repeated Exposure (Animal)

Last reviewed: 8 September 2008