Perchloroethylene , case

This paper will summarize briefly some work my colleagues and I at Decision Focus Incorporated have carried out for EPA to show how decision analysis might be used to assist decision making under TSCA ( 5). I will first briefly review the concepts of quantitative risk assessment and cost-benefit analysis to show how decision analysis fits with these concepts and provides a natural way of extending them. Then I will illustrate the approach using a case study on a specific chemical, perchloroethylene. 

Environment and health-related problems are especially determined by health risks due to solvents, which result in damage to skin and the central nervons system (polyneuropathy, encephalopathy) in the case of chronic exposure. Some solvents are also classified as being carcinogenic (e.g. benzene, trichloroethylene) or are suspected of being carcinogenic (e.g. perchloroethylene) or reproduction-toxic (e.g. toluene). 

The coexistence of various pollutants does not have to be deleterious, but, in certain cases, can be quite beneficial. The first evidence for this claim came probably from the work of Lichtin et al. (1994) who found that the edition of 0.03% by volume to an air-stream containing 0.1% iso-octane caused an enhancement in the photocatalytic oxidation of the latter. Likewise, a significant rate enhancement was recorded in the photocatalytic degradation of chloroform and dichloromethane in the presence of TCE. Similar effects were recorded also with other chlorinated olefins, such as perchloroethylene (PCE) and trichloropropene (TCP), which enhanced the photooxidation of toluene in a manner similar to that of TCE (Sauer et al., 1995). 

P. H. Fluckiger, The use of life-cycle assessment and product risk assessment unthin application development of chemicals, a case study of perchloroethylene use in dry cleaning, PhD thesis, Swiss Federal Institute of Technology Zurich, 1999. 

Lockey et al. (1987) described a 47-year-old woman with previously excellent health who developed fatal SSc after a single 2.5-h predominantly dermal exposure to trichloroethylene. During a period of 10 months, the patient developed proximal scleroderma, reflux esophagitis, microangiopathic hemolytic anemia, restrictive pulmonary disease, pericarditis with effusion, and renal insufficiency with severe hypertension. Renal and skin biopsies were consistent with SSc. An additional case of SSc in a 51-year-old female worker has been presented, who developed SSc after 15 years of exposure to perchloroethylene (Szeimies et al. 1992). 

The contamination of equipment such as transformers either to be recycled or simply to be removed empty can also be cause for concern. After the equipment has been cleaned, the solvent used should be monitored. For example, it may be necessary to evaluate the PCB content in perchloroethylene, which, as is the case for any other solvents, poses no problems. 

In the case of water purification, the main problem is waste from industry [2] and agriculture, which turns into potentially dangerous substances as it comes in contact with water. Moreover, volatile organic compounds (VOCs) such as formaldehydes, acetones, chlorobenzenes, xylene, perchloroethylene, and tetra-chloroethylene are responsible for the formation of the chemical cloud [3] that mainly occurs in urban areas, generating ozone-rich atmospheres harmful to health. 

In the case of fish, exposed to solutions in water, some accumulation occurs, especially in the liver, bioconcentration factors reported range from 2 for ethylene dichloride in whole fish to 400 for perchloroethylene in liver, followed by very rapid loss after exposure ceased [6, 43]. No evidence for metabolism has been found but the possibility should certainly not be excluded. 

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