• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.1
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• pp.3-13
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• 1993

This study was conducted at seven degreasing processes in plating plants located in Seoul, Incheon, Ansan, and Taejeon areas from July 21 to august 27, 1992. This study was performed to assess the TWA exposures to trichloroethylene (TCE) and evaluate factors affecting TCE concentrations in degreasing process. Two-Point Eddy Diffusional Model suggested by Wadden et al. was employed to calculalte emission factors according to degreaser type. Results are summarized as follows. 1. The TWA exposures of the degreasing operators ranged from 1.4 ppm to 123 ppm, and those of three plants out of seven were exceeding 50 ppm of both the Korean and U.S. OSHA standards. Degreasing assistant of Plant B, was exposed to 59 ppm. 2. The average concentrations at the distance 0, 1.5, 3.0 m from the degreasers were 1.014, 24, and 18 ppm, respectively, and showed a signifficant difference by distance (p<0.01). 3. The emission of TCE was reduced by installing local exhaust systems, condensers, and refrigeration lines at the degreasers (p<0.01). 4. The major factors related to exposure of operators were workload (r=.9621. p<0.01) and dimensions of degreansing room(r=-.8667, p<0.05). 5. If the air in degreasing room is mixed violently by other factors in addition to diffusion, the emission factors can not be evaluated because the important hypothesis of the Two-Point Eddy Diffusional Model can not be accepted. 6. The ultrasonic degreaser without the local exhaust ststem, condenser, and refrigeration lines emitted TCE three times greater than the ultrasonic degreaser with condenser and refrigeration 1ines only.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.277-280
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• 2004

TCE and PCE, suspected carcinogens, are the most common groundwater pollutant from extensive use as a solvent and degreaser. Escherichia coli TGI pBSKAN TOM Green and E. coli TGI pBSKAN ToMO, which were used DNA shuffling technique, produce Toluene-o-monooxygenase(TOM) and toluene-o-xylene- monooxygenase(ToMO). These cells and enzymes are degrading TCE and PCE, TOM and ToMO are needed to cofactor, such as NADH, NADPH and other cofactors. Used TCE and PCE degrading microorganisms experiment the contaminated material removal efficiency. A shunting test used NAD and Hydrogen peroxide.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.171-174
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• 2005

Suspected carcinogen, TCE and PCE, are the most common groundwater pollutants extensively used as a solvent and degreaser. In this study, oxygenases were immobilized in Ca-alginate and chitosan bead. TCE degradation by the immoblized enzyme beads were measured for various size, enzyme addition volume and TCE contact time. The degradation was decreased as increasing the bead size. For overnight , more than 20% of TCE was degraded. The variation of enzyme activity was tested for the repeated use of enzyme beads.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.17 no.3
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• pp.254-260
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• 2007

Trichloroethylene(TCE) is widely used as a degreasing solvent in workplaces. TCE is primarily toxic to the nervous system, however, systemic disorder like Stevens-Johnson syndrome has been recently reported in small-scale factories, where the government has had limited information of chemical use. A survey was performed to investigate the actual condition of using TCE and to provide practical information to occupational health service agencies and professionals. This survey was carried out on 103 factories out of 430 factories which were conducted periodic work environment measurement for TCE. Degreasing was the most popular reason for using TCE in Korea, which reached to 94%. TCE was also used as a solvent for rubber in the coating or molding process, and adhesives in the bonding process. Metal fabrication was the most common as 23%, followed by assembling automobile parts (17%), and machinery (12%). Workers exposed to TCE during full-shift were 52% while 48% were exposed during short period of the shift or intermittently. Manual or semi-automatic work occupied 87% while automatic work was just 13%. Though automatic work by a closed system was generally lower exposed to TCE, compared to manual work, it can cause a high exposure when the maintenance system is improper. Semi-automatic work especially like open-top degreasing process can cause a high exposure when local exhaust system with condensing and refrigerating coils in the degreaser does not work well. In conclusion, the survey showed nationwide status of TCE exposure in various aspects. It can be used to monitor workplaces and workers exposed to TCE to prevent occupational diseases.