Tetrachloroethylene-contaminated

Existing Information on Health Effects of Tetrachloroethylene 5-1 Frequency ofNPL Sites with Tetrachloroethylene Contamination... 

Developmental Effects. Studies examining the association between drinking water contamination and birth outcome in humans suggest that there may be an association between birth defects, especially oral cleft defects, and tetrachloroethylene contamination (Bove et al. 1995 Lagakos et al. 1986). These studies are confoiuided by more than one contaminant, and the Lagakos et al. (1986) study combined birth defects in the analysis in a manner that has questionable biological relevance. 

FIGURE 5-1 FREQUENCY OF NPL SITES WITH TETRACHLOROETHYLENE CONTAMINATION ... 

No information on analysis of tetrachloroethylene in soil or sediment was located. Several procedures for determination of the chemical in plants and food were located. GC/ECD and GC/HSD are most commonly used to analyze solid samples for tetrachloroethylene contamination. Extraction, purge-and-trap, and headspace analysis have all been used to prepare samples. Analysis of headspace gases by GC coupled with ECD, MS, or HSD has proven relatively sensitive (low- to sub-ppb range) and reproducible for a variety of foods (Boekhold et al. 1989 Entz and Hollifield 1982 EPA 1982c Pocklington 1992 ... 

Aschengrau A, Ozonoff D, Paulu C, et al. 1993. Cancer risk and tetrachloroethylene-contaminated drinking water in Massachusetts. Archives of Environmental Health 48(5) 284-292. 

Wakeham SG, Davis AC, Witt RT, et al. 1980. Tetrachloroethylene contamination of drinking water by vinyl-coated asbestos-cement pipe. Bull Environ Contam Toxicol 25 639-645. 

Nonaqueous phase Hquids (NAPLs) present special problems for soil and ground water cleanup. Contaminant transport through ground water depends in part on the water solubiHty of the compound. Because NAPLs cling to subsurface particles and are slow to dissolve in ground water, they hinder cleanups and prolong cleanup times. Dense nonaqueous phase Hquids (DNAPLs) migrate downward in the aquifer and can coUect in pools or pockets of the substmcture. Examples of DNAPLs are the common solvents tetrachloroethylene (PCE) and trichloroethylene (TCE) which were used extensively at many faciHties before the extent of subsurface contamination problems was realized. 

Groundwater Industrial contamination of ground water reserves Reduction of total organic halogens (TOX) and adsorbable organic halogens (AOX) including chloroform, tetrachloroethylene, and trichloroethylene... 

Respiratory Effects. One study suggested increased respiratory disorders (asthma, bronchitis, pneumonia) in children with chronic exposure to a solvent-contaminated water supply (Byers et al. 1988). Two municipal wells in eastern Woburn, Massachusetts, were found to contain several solvents including trichloroethylene (267 ppb) and tetrachloroethylene (21 ppb). The increased susceptibility to infection may be secondary to effects on the immune system. Accurate chemical-specific exposure levels for individuals could not be determined because the water distribution system was designed to use water from different wells at different rates and times. Other limitations of this study are described in Section 2.2.2.8. 

Release of trichloroethylene also occurs at treatment and disposal sites. Water treatment facilities may release trichloroethylene from contaminated water through volatilization and air-stripping procedures (EPA 1985e). Trichloroethylene is also released to the atmosphere through gaseous emissions from landfills. The compound may occur as either an original contaminant or as a result of the decomposition of tetrachloroethylene. Trichloroethylene has also been detected in stack emissions from the incineration of municipal and hazardous waste (James et al. 1985 Oppelt 1987). 

U.S. EPA. Preliminary study of selected potential environmental contaminants - Optical brighteners, methyl chloroform, trichloroethylene, tetrachloroethylene, ion exchange resins. Office of Toxic Snbstances, Report 560/2-75-002,1975,286 p. U.S. EPA. Report on the problem of halogenated air pollntants and stratigraphic ozone. Office of Research and Development, Report-600/9-75-008, 1975a, 55 p. 

Groundwater contaminated with other halogenated solvents can also be treated in aboveground reactors. Aerobic reactors are useful for those compounds that can support growth. Sequential anaerobic and aerobic reactors are capable of mineralizing tetrachloroethylene. 

The biodegradation of trichloroethylene is the most studied since this is probably the most widespread halogenated solvent contaminant. Several substrates drive ttichlorethylene co-oxidation, including methane, propane, propylene, toluene, isopropylbenzene, and ammonia (25). The enzymes that metabolize these substrates have subtly different selectivities with regard to the halogenated solvents, and to date none are capable of co-oxidizing carbon tetrachloride or tetrachloroethylene. Complete mineralization of these compounds can, however, be achieved by sequential anaerobic and aerobic process. Biorem edia tion. 

DNAPLs examined include chlorobenzene (CB), 1,2-dichlorobenzene (1,2-DCB), trichloroethylene (TCE) and tetrachloroethylene (PCE). These DNAPLs were selected because of their relevance as environmental contaminants, and because they cover a range of polarities and densities. All DNAPLs were purchased from Sigma (St. Louis, MO) and were used as received. 

Pennell, K. D. Jin. M. Abriola, L. M. Pope, G.A. "Surfactant Enhanced Remediation of Soil Columns Contaminated by Residual Tetrachloroethylene." J. Contam. Hydrol. 1994 16, 35-53. 

Pennell, K.D., Jin, M., Abriola, L.M., and Pope, G.A. (1994). Surfactant enhanced remediation of soil columns contaminated by residual tetrachloroethylene. J. Contain. Hydrol., 16,35-53. 

Inorganic Syntheses, 9, 135-136 (1967)] is placed in chamber A of the vessel. This operation is carried out in an inert atmosphere to avoid contamination by oxyhal-ides. The vessel is then evacuated on the vacuum line, and 25 ml. of previously dried and degassed tetrachloroethylene is vacuum distilled onto the tungsten(VI) chloride. The solution is frozen, and the... 

The quantitative synthesis of molybdenum(IV) chloride 1ms been similarly accomplished in a two-day reaction at 150° in the presence of a 100-watt light bulb. However, purification cannot be done by sublimation due to the thermal instability of the product. Thus it is necessary to extract the product with the excess tetrachloroethylene to remove excess molybdc-num(V) chloride and hexachloroethane. The reaction and extraction of the product can be conveniently done in a single vessel as described elsewhere.12 This is not as convenient as the method of Larson and Moore13 but it does avoid contamination by carbonaceous impurities which result in the benzene reduction of molybdenum(V) chloride. 

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