Trichloroethylene experiment

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. 

Experiments were conducted in which purified trichloroethylene (1 mg in acetone) was applied to the shaved backs of female ICR/Ha Swiss mice (Van Duuren et al. 1979). In an initiation-promotion study, a single application of trichloroethylene was followed by repeated application of phorbol myristate acetate (PMA) promoter. In a second study, mice were treated with trichloroethylene three times per week without a promoter. No significant tumor incidences were observed in these studies. Doses used in these studies were well below the maximum tolerated dose, which is often not reached in dermal studies. 

Experiments demonstrate that oral absorption of trichloroethylene in animals is extensive and metabolism is rapid. A study of F344 rats which were fasted for 8 hours prior to oral dosing by gavage found a rapid appearance of trichloroethylene in the blood which peaked after 0.75 hours, while the peak concentrations of the metabolites trichloroethanol and TCA occurred at 2.5 and 12 hours, respectively (Templin et al. 1995). The same investigators also dosed beagle dogs and found that blood concentrations of trichloroethylene, trichloroethanol, and TCA peaked after 1, 2.5, and 24 hours, respectively. In both species, TCA concentration did not peak until well after the trichloroethylene concentration in blood was below detectable levels (Templin et al. 1995). 

In the past, trichloroethylene was used as a human anesthetic. Trichloroethylene has also been used by individuals who intentionally inhale it for its narcotic properties. Therefore, most of the information regarding the effects of trichloroethylene in humans comes from case studies and experiments describing effects of trichloroethylene after inhalation exposure. These studies indicate that the primary effect of exposure to trichloroethylene is on the central nervous system. Effects include headache, vertigo, fatigue, short-term memory loss, decreased word associations, central nervous system depression, and anesthesia. 

The use of the methods for monitoring metabolites of trichloroethylene in blood and urine is, however, rather limited since the levels of TCA in urine have been found to vary widely, even among individuals with equal exposure (Vesterberg and Astrand 1976). Moreover, exposure to other chlorinated hydrocarbons such as tetrachloroethane, tetrachloroethylene, and 1,1,1-trichloroethane would also be reflected in an increase in urinary excretion of TCA. In addition, there may be sex differences regarding the excretion of trichloroethylene metabolites in urine since one experiment shows that men secrete more trichloroethanol than women (Inoue et al. 1989). The use of the level of trichloroethylene adduction to blood proteins as a quantitative measure of exposure is also possible, although obtaining accurate results may be complicated by the fact that several metabolites of trichloroethylene may also form adducts (Stevens et al. 1992). 

Studies of workers and volunteers in experiments have provided most of the data on health effects of inhaled trichloroethylene in humans. Most of the information on reported effects in humans following oral exposure... 

Adams EM, Spencer HC, Rowe VK, et al. 1951. Vapor toxicity of trichloroethylene determined by experiments on laboratory animals. Arch Ind Hyg Occup Med 4 469-481. 

Experimental design Six humans (sex unspecified) were exposed to 200 ppm trichloroethylene for 5 days, 7 hours/day in a confined chamber. Previous experiments had shown no effects at lower concentrations. No controls were used in this study. 

Practical experience from the application of SVE at sites contaminated with a single type of contaminant (e.g., trichloroethylene, TCE) indicates that the removal of contaminants follows a trend in two distinct phases. During the initial phase, which covers the period from the project startup to the exhaustion of NAPL in the subsurface, the removal rate is almost linear. The second phase is characterized by a constant decrease in removal rates. 

The interaction of /2-hexane with toluene and trichloroethylene has also been examined in volunteers (Baelum et al. 1998). Exposure in these experiments was via a gastric feeding tube at controlled rates equivalent to what the authors stated would be delivered to the liver by inhalation exposure at Danish occupational exposure limits (50 ppm /7-hexane. 50 ppm toluene, and 30 ppm trichloroethylene). Coexposure to toluene and trichloroethylene slightly increased the area under the curve (AUC) representing concentration versus time for end exhaled /2-hexane air concentration, but urinary excretion of 2,5-hexanedione was unchanged. The only statistically significant interaction observed with /2-hexane was an 18% decrease in the urinary excretion of hippuric acid, a toluene metabolite. 

Kinsella, J. V. and Nelson, M. J. K., 1993, In Situ Bioremediation Site Characterization, System Design, and Full Scale Field Remediation of Petroleum Hydrocarbon and Trichloroethylene Contaminated Groundwater In Bioremediation Field Experience (edited by P. E. Flathman and D. E. Jerger), CRC Press, Boca Raton, FL. 

Zhang and Wang (1997) studied the reaction of zero-valent iron powder and palladium-coated iron particles with trichloroethylene and PCBs. In the batch scale experiments, 50 pL of 200 pg/mL PCB-1254 in methanol was mixed with 1 ml ethanol/water solution (volume ratio = 1/9) and 0.1 g of wet iron or palladium/iron powder in a 2-mL vial. The vial was placed on a rotary shaker (30 rpm) at room temperature for 17 h. Trichloroethylene was completely dechlorinated by the nanoscale palladium/iron powders within the 17-h time period. Only partial dechlorination of PCB-1254 was observed when wet iron powder was used. 

An aqueous solution containing 300 ng/ iL trichloroethylene and colloidal platinum catalyst was irradiated with UV light. After 12 h, 7.4 ng/pL trichloroethylene and 223.9 ng/pL ethane were detected. A duplicate experiment was performed but 1 g zinc was added to the system. After 5 h, 259.9 ng/pL ethane was formed and trichloroethylene was nondetectable (Wang and Tan, 1988). Major products identified from the pyrolysis of trichloroethylene between 300-800 °C were carbon tetrachloride, tetrachloroethylene, hexachloroethane, hexachlorobutadiene, and hexachlorobenzene (Yasuhara and Morita, 1990). 

In a laboratory experiment, 5 mL of 6.3 mM of potassium permanganate was injected into a 50-mL vial trichloroethylene of 0.1 mM aqueous solution. Trichloroethylene underwent rapid oxidation. Products identified before oxidizing to carbon dioxide and hydrogen chloride were formic, glycolic, glyoxylic, and oxalic acids. At pH 4, 77% of the trichloroethylene was converted... 

Zhong et al. (2003) studied the apparent solubility of trichloroethylene in aqueous solutions, where the experimental variables were surfactant type and cosolvent concentration. The surfactants used in the experiment were sodium dihexyl sulfo-succinte (MA-80), sodium dodecyl sulfate (SDS), polyoxyethylene 20 (POE 20), sorbitan monooleate (Tween 80), and a mixture of Surfonic- PE2597 and Witconol-NPIOO. Isopropanol was used as the alcohol cosolvent. Eigure 8.20 shows the results of a batch experiment studying the effects of type and concentration of surfactant on solubilization of trichloroethylene in aqueous solutions. A correlation between surfactant chain length and solubilization rate may explain this behavior. However, the solubilization rate constants decrease with surfactant concentration. Addition of the cosolvent isopropanol to MA-80 increased the solubility of isopropanol at each surfactant concentration but did not demonstrate any particular trend in solubilization rate of isopropanol for the other surfactants tested. In the case of anionic surfactants (MA-80 and SDS), the solubility and solubilization rate increase with increasing electrolyte concentration for all surfactant concentrations. 

In a combined-exposure experiment oral administration of trichloroethylene containing 1,2-epoxybutane induced squamous cell carcinomas of the forestomach in mice, whereas administration of the trichloroethylene alone did not. ... 

This technology is currently the focus of pilot-scale experiments by Battelle Pacific Northwest Laboratories (PNL), which has shown GPCR has the potential to destroy trichloroethylene and naphthalene with greater than 99.9% efficiency. Tests with other pollutants, including biological and chemical warfare agents, have been undertaken. Capital costs are projected to be lower than many baseline technologies. 

Many of the bisbenzocyclobutene polymers are relatively unaffected by organic solvents and aqueous media. In Table 11 are shown some of the results which were obtained in a solvent pick-up study carried out on the bisbenzocyclobutene polyester 40 [2]. Of all of the solvents, only trichloroethylene and methyl ethyl ketone were absorbed to any significant extent at 70 °C over the four-week course of the experiment. None of the polymer samples dissolved in the solvents that were tested and only a slight swelling was observed with those liquids which were significantly absorbed. The small effect of aqueous sodium hydroxide on the bisbenzocyclobutene polyester is deserving of note since a control sample of a commercial polyimide (Vespel ) dissolved completely in two days under the conditions of this test. 

Figure 9.6 Comparative separation factors for toluene and trichloroethylene from water with various rubbery membranes [28]. These experiments were performed with thick films in laboratory test cells. In practice, separation factors obtained with membrane modules are far less because of concentration polarization effects. Reprinted from Nijhuis et al. [28], p. 248 with permission of Bakish Materials Corporation, Englewood, NJ...

The loss of VOCs from soil during sampling, shipping, storage, and even during analysis itself is a well-documented problem. For example, when exposed to air at room temperature, a soil sample will experience a 100 percent reduction in the trichloroethylene concentration within 1 hour (Flewitt 1996). 

Trichloroethylene and PCE have also been irradiated on a process scale at the EBRF [55]. Unlike in the aromatic solute experiments above, increasing pH necessitated increased radiation requirements. Formic acid and smaller amounts of formaldehyde, acetaldehyde, and trace glyoxal were the detectable products. No detectable chloroacetic acids were reported, indicating that if produced they were decomposed by continued irradiation. 

Casey FXM, Ong SK, Horton R. Degradation and transformation of trichloroethylene in miscible displacement experiments through zerovalent metals. Environ Sci Technol 2000 34 5023-5029. 

U.S. and one industrial waste water treatment in Spain. Engineering scale field experiments have been conducted by the National Renewable Energy Laboratory (NREL) at the Lawrence Livermore National Laboratory (LLNL) treating ground water contaminated with trichloroethylene (TCE) [253]. This field system consisted of 158 m2 of parabolic trough reactors and used De-gussa P25 particles (0.1%) as the photocatalyst in a slurry flow configuration. With this relatively low titanium dioxide content the TCE concentration was reduced from 200 ppb to less than 5 ppb. 

Fig. 3.3 Diffusion method used to prepare surface gradients of methyl groups according to Elwing et al.48,54 Silicon or glass substrates are placed in a container filled with xylene. Trichloroethylene (Tri) with 0.1% (v/v) DDS is bedded under the xylene phase because of its higher density. The methylsilane diffuses together with Tri into the xylene phase and binds simultaneously to the SiOH groups on the silicon surface. The experiment is interrupted by removal of the solutions through the drain...

Chlorinated organic contaminants are found at various sites of interest to the U.S. Air Force. Among these contaminants are compounds such as tetrachloroethylene, dichloroethane, trichloroethylene, chlorobenzene, benzene, toluene, and components of JP-4 jet fuel. These materials have a boiling range of 80° to 232°C, have substantial vapor-pressure at 100°C, and can be steam distilled if present in excess of their solubility limit. To establish the feasibility of thermal recovery of such chemical contaminants, tetrachloroethylene (120.8°C, nbp) was selected as a representative contaminant. Uncontaminated (clean) sandy soil from the vicinity of a waste site was spiked with tetrachloroethylene and used in recovery experiments. 

In addition to the investigation of numerous model compounds, real wastes from chemical, pharmaceutical and food industry, from municipal sewage treatment plants, and from military and nuclear power facilities were tested in bench and pilot scale plants [110]. For a better understanding of supercritical water oxidation, single components like 2,4-dinitrotoluene, acetic acid, ammonia, aniline, cyanide, dichloromethane, ethanol, formic add, hexachlorocydohexane, hydrogen, phenol, PVC, DDT, pyridine, thiophene, toluene, trichloroethylene, and 1,1,1-trichloroethane were studied. From these experiments, kinetic data were obtained. The destruction efficiency, which is the ratio between the residual total organic carbon content (TOC) and the initial TOC achieved for these compounds is up to 99.999 % [83]. Also flames in supercritical water, e.g. by oxidation of methane with oxygen, have been studied [111, 112]. 

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