title: Biological exposure assessment to tetrachloroethylene for workers in the dry cleaning industry.
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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Centers for Disease Control and Prevention (CDC) National Institute for Occupational Safety and Health, 4676 Columbia Parkway, R-15, Cincinnati, OH 45226, USA. LTaylor@cdc.gov
authors.forename: Lauralynn T
authors.initials: LT
authors.lastname: McKernan
authors.forename: Avima M
authors.initials: AM
authors.lastname: Ruder
authors.forename: Martin R
authors.initials: MR
authors.lastname: Petersen
authors.forename: Misty J
authors.initials: MJ
authors.lastname: Hein
authors.forename: Christy L
authors.initials: CL
authors.lastname: Forrester
authors.forename: Wayne T
authors.initials: WT
authors.lastname: Sanderson
authors.forename: David L
authors.initials: DL
authors.lastname: Ashley
authors.forename: Mary A
authors.initials: MA
authors.lastname: Butler
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D001944:Breath Tests; D004784:Environmental Monitoring / Q000379:methods; D005260:Female; D006801:Humans; D007846:Laundering; D008875:Middle Aged; D016273:Occupational Exposure / Q000032:analysis*; D010865:Pilot Projects; D012044:Regression Analysis; D012997:Solvents / Q000032:analysis; D013750:Tetrachloroethylene / Q000032:analysis* / Q000097:blood / Q000652:urine
chemical_list: D012997:Solvents; D013750:Tetrachloroethylene