Sources, Emission And Exposure To Trichloroethylene (TCE) And Related Chemicals
This report documents the sources, emission, environmental fate and exposures for TCE, some of its metabolites, and some other chemicals known to produce identical metabolites. The major findings for TCE are:
- The primary sources releasing TCE to the environment are metal cleaning and degreasing operations. Releases occur to all media, but mostly to the air,
- TCE is very volatile, and most TCE released to the environment eventually goes into the air. It is also moderately soluble in water and can leach from soils into the ground water,
- TCE has commonly been found in ambient air, surface water, and ground waters. The 1998 air levels in µg/m3 across 115 monitors can be summarized as follows: range = 0.01 to 3.9, mean = 0.88. A California survey of large water utilities in 1984 found a median concentration of 3.0 µg/L. The literature reports levels in drinking water as trace to 50 µg/L and in food as 1 to 70 µg/kg. Median levels in ambient waters may be about 0.1 µg/L,
- General population exposure occurs primarily by inhalation and water ingestion. Typical average daily intakes have been estimated as 11 to 33 µg/day for inhalation and 2 to 20 µg/day for ingestion. A small portion of the population is expected to have elevated exposures as a result of one or more of these pathways:
- inhalation exposures to workers involved in degreasing operations,
- ingestion and inhalation exposures occurring in homes with private wells located near disposal/contamination sites, and
- inhalation exposures to consumers using TCE products in areas of poor ventilation,
- More current and more extensive data on TCE levels in indoor air, water, and soil are needed to better characterize the distribution of background exposures in the general population and elevated exposures in special subpopulations.
- More data are needed for other TCE related chemicals.