Subject trichloroethylene

Dermal Effects. Humans that were experimentally exposed to 200 ppm of trichloroethylene vapor for 7 hours experienced dry throats (40% of the subjects), begiiming after 30 minutes (Stewart et al. 1970). The subjects experiencing these symptoms did not experience them when exposed in the same manner on 5 other consecutive days. These effects are presumed to be due to direct contact with the vapor. Skin irritation and rashes have resulted from occupational exposure to trichloroethylene (Bauer and Rabens 1974 El Ghawabi et al. 1973). The dermal effects are usually the consequence of direct skin contact with concentrated solutions, but occupational exposure also involves vapor contact. Adverse effects have not been reported from exposure to dilute aqueous solutions. 

Experimental exposure studies have attempted to associate various neurological effects in humans with specific trichloroethylene exposure levels. Voluntary exposures of 1 hours resulted in complaints of drowsiness at 27 ppm and headache at 81 ppm (Nomiyama and Nomiyama 1977). These are very low exposure levels, but the results are questionable because of the use of only three test subjects per dose, lack of statistical analysis, sporadic occurrence of the effects, lack of clear dose-response relationships, and discrepancies between the text and summary table in the report. Therefore, this study is not presented in Table 2-1. No effects on visual perception, two-point discrimination, blood pressure, pulse rate, or respiration rate were observed at any vapor concentration in this study. Other neurobehavioral tests were not performed, and the subjects were not evaluated following exposure. 

In studies designed to examine dermal absorption of trichloroethylene, emersion of the hand (Sato and Nakajima 1978) or thumb (Stewart and Dodd 1964) for 30 minutes was reported to be pairrful. The pain was described as excruciating in one study (Sato and Nakajima 1978), and in another study it was described as mild by one subject and moderately severe by two subjects (Stewart and Dodd 1964). Occupational exposure to trichloroethylene that involved both dermal and inhalation exposure has been reported to result in dizziness, headache, insomnia, lethargy, forgetfulness, and loss of feeling in the hands and feet (Bauer and Rabens 1974 Kohlmuller and Kochen 1994). 

Rapid dermal absorption of trichloroethylene is evident from a study in which peak blood and exhaled air concentrations occurred within 5 minutes after a human subject immersed one hand in a solution of unspecified trichloroethylene concentration for 30 minutes (Sato and Nakajima 1978). Studies on dermal absorption of trichloroethylene in humans, as well as animals, are complicated by the fact that exposure in these studies is usually by direct contact of the skin with the undiluted chemical. Trichloroethylene is a lipophilic solvent that defats the skin and disrupts the stratum comeum, thereby enhancing its own absorption. Thus, the rate of absorption probably increases in a nonlinear fashion with greater epidermal disruption. Although the extent of absorption through the skin may be relatively modest with normal industrial use (Sato and Nakajima 1978 Stewart and Dodd 1964), there is insufficient information to evaluate the effects of chronic, low-level exposure in hiunans, especially when multiple routes may be involved. 

Elevated trichloroethylene levels in expired air were measured in subjects who immersed one hand in an unspecified concentration of trichloroethylene for 30 minutes (Sato and Nakajima 1978). Guinea pigs, exposed to dilute concentrations of aqueous trichloroethylene (-0.020 to 0.110 ppm) over a majority of their body surface area for 70 minutes, excreted 59% of the administered dose in the urine and feces 95% of the metabolized dose was excreted in 8.6 days (Bogen et al. 1992). No other studies were located for humans or animals regarding excretion after dermal exposure to trichloroethylene. 

Pain and erythema have been reported by study subjects who stuck their hands (Sato and Nakajima 1978) or thumbs in trichloroethylene (Stewart and Dodd 1964). Application of trichloroethylene to the skin of guinea pigs resulted in erythema and edema. 

Trichloroethylene is on the list of chemicals appearing in "Toxic Chemicals Subject to Section 313 of the Emergency Plaiming and Community Right-to-Know Act of 1986" (EPA 19871, 1988c). 

Bartonicek V. 1962. Metabolism and excretion of trichloroethylene after inhalation by human subjects. Br J Ind Med 19 134-141. 

Kohlmueller D, Kochen W. 1994. Exhalation air analyzed in long-term postexposure investigations of acetonitrile and trichloroethylene exposures in two subjects. Clin Chem 40 1462-1464. 

Liu YT, Jin C, Chen Z, et al. 1988. [Increased subjective symptom prevalence among workers exposed to trichloroethylene at sub-OEL levels.] Tohoku J Exp Med 155 183-195. (Japanese)... 

Malek B, Kremarova B, Rodova A. 1979. [An epidemiological study of hepatic tumor incidence in subjects working with trichloroethylene. II. Negative result of retrospective investigations in dry cleaners.] Prac Lek 31 124-126. (Czech)... 

Mixtures of the tetraoxide with dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, trichloroethylene and tetrachloroethylene are explosive when subjected to shock of 25 g TNT equivalent or less [1], Mixtures with trichloroethylene react violently on heating to 150°C [2], Partially fluorinated chloroalkanes were more stable to shock. Theoretical aspects are discussed in the later reference [2,3], The effect of pressure on flammability limits has been studied [4],... 

National legislation which lay down a general prohibition on the use of Trichloroethylene for industrial purposes and establishes a system of individual exemptions, granted subject to conditions, is justified under Article 36 of the EC Treaty (now, after amendment. Article 30 EC, on the grounds of protection of health of humans. ... 

Trichloroethylene in aqueous solutions at concentrations ranging from 1 to 10% of the solubility limit were subjected to y rays. At a given radiation dose, as the concentration of the solution decreased, the rate of decomposition increased. As the radiation dose and solute concentration were increased, the concentrations of the following degradation products also increased methane, ethane, carbon dioxide, hydrogen, and chloride ions. Conversely, the concentration of oxygen decreased with increased radiation dose and solute concentration (Wu et al., 2002). 

Many groundwaters are contaminated with the cleaning solvents trichloroethylene (TCE) and perchloroethylene (PCE). They are two of the most common organochlorine compounds found in Superfund sites. Radiation-induced decomposition of TCE in aqueous solutions has been the subject of several recent studies [15-20]. In most of the referenced studies, the complete destruction of TCE was observed. Dechlorination by a combination of oxidative and reductive radiolysis was stoichiometric. Gehringer et al. [15] and Proksch et al. [18] have characterized the kinetics and mechanism of OH radical attack on TCE and PCE in y-ray-irradiated aqueous solution. Trichloroethylene was readily decomposed in exponential fashion, with a reported G value of 0.54 pmol J-1. A 10 ppm (76 pM) solution was decontaminated with an absorbed dose of less than 600 Gy. For each OH captured, one C02 molecule, one formic acid molecule and three Cl- ions were generated. These products were created by a series of reactions initiated by OH addition to the unsaturated TCE carbon, which is shown in Eq. (45) ... 

Preparatory to painting, the polypropylene components are subjected to trichloroethylene or 1,1,1 -trichloroethane which (especially if fillers or other materials are present in the composition) will remove grease and permeate the surface. However, it should be remembered that for environmental and health reasons the use of solvents like these is regulated strictly. 

Certain adhesive materials are hazardous when mixed together. Epoxy and polyester catalysts, especially, must be well understood, and the user should not depart from the manufacturers recommended procedure for handling and mixing. Certain unstabilized solvents, such as trichloroethylene and perchloroethylene, are subject to chemical reaction on contact with oxygen or moisture. Only stabilized grades of solvents should be used. 

Exposure of 5 subjects to a concentration of 100 ppm of trichloroethylene for 6 hours produced mean peak blood concentrations of about 1 pg/ml of trichloroethylene 2 hours after the start of exposure, and about 6 pg/ml of trichloroethanol at the end of the exposure period (G. Muller et al., Arch. Tox., 1974,32, 283-295). 

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