應用呼出氣體濃度檢測四氯乙烯之體內劑量及暴露值

Breath Smpling as an Indicator of Internal Dose after Tetrachloroethylene Exposure

錢葉忠 ； Clifford P. Weisel

《中華職業醫學雜誌》 4卷3期 (1997/07) Pp. 133-140

摘要

Body absorption and elimination kinetics during and after tetrachloroethylene exposures were examined from a field and a controlled exposure study using exhaled breath analysis. Short-term exposure air and alveolar breath samples were collected simultaneously to investigate the body’s response to environmental changes and to estimate absorbed (internal) dose. A single subject was used throughout the study to eliminate inter-individual variability. During the exposure, the changes of breath concentration closely reflect the changes of air concentration. Absorbed (internal) doses are highly (r2=099, P＜.05) correlated with total exposures. Postexposure breath concentrations in general reflect internal dose but are affected by exposure duration, especially during the early elimination phase. Higher percentage of the absorbed Perc was expired shortly following exposure when exposure duration was shorter. The results of controlled exposure study also showed that, for the same total exposures, shorter exposure resulted in statistically significantly higher (p＜.05) internal dose and higher percent dose expired, during the first postexposure hours. These findings suggested that postexposure breath concentrations, though are useful in assessing the internal dose attributed to environmental Perc exposures, are a function of exposure duration or exposure concentration. Therefore, exposure duration should be determined if postexposure breath concentrations are to be used to estimate internal dose or past exposures. The field exposure measurement also suggest a need to shorten the stay in commercial Laundromats with dry-cleaning operation to minimize the Perc exposure at low-ppm levels.

並列摘要

Body absorption and elimination kinetics during and after tetrachloroethylene exposures were examined from a field and a controlled exposure study using exhaled breath analysis. Short-term exposure air and alveolar breath samples were collected simultaneously to investigate the body’s response to environmental changes and to estimate absorbed (internal) dose. A single subject was used throughout the study to eliminate inter-individual variability. During the exposure, the changes of breath concentration closely reflect the changes of air concentration. Absorbed (internal) doses are highly (r2=099, P＜.05) correlated with total exposures. Postexposure breath concentrations in general reflect internal dose but are affected by exposure duration, especially during the early elimination phase. Higher percentage of the absorbed Perc was expired shortly following exposure when exposure duration was shorter. The results of controlled exposure study also showed that, for the same total exposures, shorter exposure resulted in statistically significantly higher (p＜.05) internal dose and higher percent dose expired, during the first postexposure hours. These findings suggested that postexposure breath concentrations, though are useful in assessing the internal dose attributed to environmental Perc exposures, are a function of exposure duration or exposure concentration. Therefore, exposure duration should be determined if postexposure breath concentrations are to be used to estimate internal dose or past exposures. The field exposure measurement also suggest a need to shorten the stay in commercial Laundromats with dry-cleaning operation to minimize the Perc exposure at low-ppm levels.