Document ID: chunk:federal_register_of_legislation:F2013C00288:reg:1:p1
Version: federal_register_of_legislation:F2013C00288
Segment Type: reg
Provision Reference: reg 1 (pt 1/10)
Character Range: 2737065–2739926

1                   Trichloroethene (TCE)

1.1              General
Several comprehensive reviews of trichloroethene (TCE) in the environment and its toxicity to humans are available and should be consulted for more detailed information not presented in this summary (ATSDR 1997; WHO 1985; EU 2004; CCME 2007; NICNAS 2009; US EPA 2011). The following provides a summary of the key aspects of TCE that are relevant to the derivation of interim HILs.

TCE is a colourless, non-flammable, volatile liquid, with a characteristic slightly sweet odour. Most people can begin to smell TCE in air at a concentration of 100 ppm (ATSDR 1997).

TCE was not thought to occur naturally in the environment until the recent discovery in 1995 that several species of marine macro-algae and at least one species of micro-algae produce the compound. The importance of this release and potential exposure route is not currently known. TCE is mainly used as an industrial solvent in a variety of industries, primarily metal degreasing and cleaning operations. TCE can also be found in some household products, including correction fluid, paint removers, adhesives, and spot removers. TCE has also been used as a carrier solvent for the active ingredients of insecticides and fungicides; as a solvent for waxes, fats, resins, and oils; and as an anaesthetic for medical and dental use. It has also been used to extract spice oleoresins and caffeine from coffee (ATSDR 1997; WHO 1985).

TCE was manufactured in Australia for approximately 30 years from the early 1950s to the early 1980s. At present, the Australian market demand for TCE is entirely met by imports of the chemical. TCE is used widely in both large and small industries, mainly as a degreasing agent (NICNAS 2009).

If released into the environment, the following can be noted with respect to TCE (WHO 1985):
    * Air  TCE is expected to remain in the vapour phase. Removal is primarily through reaction with hydroxyl radicals to produce low levels of phosgene, dichloroacetyl chloride, formyl chloride and other degradation products. The half-life of TCE varies from 1 day to months.
    * Soil and Water  TCE is expected to volatilise from surface soils and water. TCE may leach through soil into groundwater where it may persist for years, depending on conditions.
    * Water  Depending on conditions, reductive dehalogenation to vinyl chloride may occur. Under anaerobic conditions TCE can be intrinsically biodegraded to form dichloroethene (1,1-DCE and isomers of 1,2-DCE) and vinyl chloride.

1.2              Previous HIL
No previous HIL is available for TCE (NEPC 1999).

1.3              Proposed Interim HIL
Review of available information in relation to the presence of TCE in soil indicates that the vapour inhalation pathway is the most significant/important. This pathway should be assessed on the