Biological exposure assessment to tetrachloroethylene for workers in the dry cleaning industry

Lauralynn T McKernan¹ , Avima M Ruder¹ , Martin R Petersen¹ , Misty J Hein¹ , Christy L Forrester¹ , Wayne T Sanderson² , David L Ashley³ and Mary A Butler¹

¹Centers for Disease Control and Prevention (CDC) National Institute for Occupational Safety and Health, 4676 Columbia Parkway, R-15, Cincinnati, OH 45226, USA

²University of Iowa Department of Occupational & Environmental Health, 100 Oakdale Campus, Iowa City, Iowa 52242, USA

³CDC National Center for Environmental Health, 4770 Buford Highway, F-47, Atlanta, GA 30341-3724, USA

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Environmental Health 2008, 7:12doi:10.1186/1476-069X-7-12


Published:	15 April 2008

Abstract

Background

The purpose of this study was to assess the feasibility of conducting biological tetrachloroethylene (perchloroethylene, PCE) exposure assessments of dry cleaning employees in conjunction with evaluation of possible PCE health effects.

Methods

Eighteen women from four dry cleaning facilities in southwestern Ohio were monitored in a pilot study of workers with PCE exposure. Personal breathing zone samples were collected from each employee on two consecutive work days. Biological monitoring included a single measurement of PCE in blood and multiple measurements of pre- and post-shift PCE in exhaled breath and trichloroacetic acid (TCA) in urine.

Results

Post-shift PCE in exhaled breath gradually increased throughout the work week. Statistically significant correlations were observed among the exposure indices. Decreases in PCE in exhaled breath and TCA in urine were observed after two days without exposure to PCE. A mixed-effects model identified statistically significant associations between PCE in exhaled breath and airborne PCE time weighted average (TWA) after adjusting for a random participant effect and fixed effects of time and body mass index.

Conclusion

Although comprehensive, our sampling strategy was challenging to implement due to fluctuating work schedules and the number (pre- and post-shift on three consecutive days) and multiplicity (air, blood, exhaled breath, and urine) of samples collected. PCE in blood is the preferred biological index to monitor exposures, but may make recruitment difficult. PCE TWA sampling is an appropriate surrogate, although more field intensive. Repeated measures of exposure and mixed-effects modeling may be required for future studies due to high within-subject variability. Workers should be monitored over a long enough period of time to allow the use of a lag term.