Biomonitoring Study of Dry Cleaning Workers Using Cytogenetic Tests and the Comet Assay

Abstract

Perchloroethylene (PCE) is the main solvent used in the dry cleaning industry worldwide. The aim of the present work was to evaluate the genotoxic potential of occupational exposure to PCE in dry cleaning workers. The study was carried out in 59 volunteers (30 workers, 29 controls). The genotoxic effect was evaluated by analyzing chromosome aberrations (CAs), and micronuclei (MN) and DNA damage (assessed by the comet assay) in peripheral blood lymphocytes. Environmental monitoring of exposure was carried out on personal breathing zone air samples collected during two consecutive working days by measuring the concentration of PCE air levels. The mean PCE concentration in workplace air of dry cleaning workers was 31.40 mg/m(3). There were no significant differences in CA frequency between dry cleaning workers and the controls, but analysis showed a significant association of CA frequency with employment duration and frequency of exposure to PCE. The MN frequency and DNA damage detected by alkaline comet assay were significantly increased in dry cleaning workers compared to the controls. The results suggest that (a) chronic occupational exposure to dry cleaning solvents below permissible occupational exposure limit of 70 mg/m(3) (i.e., ~10.3 ppm) may lead to an increased risk of genetic damage among dry cleaning workers, and (b) CA, MN tests, and comet assay are useful to monitor populations exposed to low doses of PCE.

Primary DNA Damage in Dry Cleaners with Perchlorethylene Exposure

“…While the genotoxic effects of exposure to PERC have been investigated previously based on chromosomal aberration and micronucleus test, 12 to the best of our knowledge, there is only another human study that used comet assay to evaluate genotoxicity in dry cleaners and found significant early DNA damage in dry cleaners. 8 Despite several animal and in vitro studies on genotoxicity of PERC based on comet assay, there are no conclusive remarks about this issue based on cytogenetic tests. Cederberg, et al , found a weak but significant increase in early DNA damage in rats exposed to PERC.…”

“…Informed verbal and written consents were obtained from all participants. Sample size calculation was conducted for tail length effect size based on what reported in Everatt study, 8 where the mean of tail length for exposed and non-exposed groups was 10.45 (SD 6.52) and 5.77 (2.31), respectively. The minimum sample size in each group for a power of 80% and a two-sided significance level of 0.05 was 31.…”

“…The comet assay was performed according to the protocol developed by Singh, et al , 6 with slight modifications. 8 Briefly, a frosted microscopic slide was cleaned with ethanol and then dipped into 1% normal melting point agarose (NMA). Twenty μL of blood cell suspensions were mixed with 80 μL of 0.7% (w/v) low-melt agarose (LMA) at 37 °C.…”

“…7 Available literature about DNA damage in dry cleaners exposed to PERC is limited and to the best of our knowledge, there is only another study based on comet assay on dry cleaners exposed to the PERC. 8 The objective of this study was to evaluate the extent of primary DNA damage in dry cleaners who were exposed to PERC in their work environment. The effect of exposure modifying factors such as use of personal protective equipment, perceived risk, and reported safe behaviors on observed DNA damage were also studied.…”

Comet assay as a sensitive technique in occupational health studies; A literature review

“…The DNA damage detected by alkaline comet assay was significantly higher in dry-cleaning workers than the controls. Comet assay was found to be a useful method for monitoring populations exposed to the low doses of PCE (22). Toluene is widely used in many industries.…”