Exposure to polycyclic aromatic hydrocarbons in coal liquefaction workers: impact of a workwear policy on excretion of urinary 1-hydroxypyrene.

OBJECTIVE

This study was undertaken to assess whether contaminated personal clothing worn beneath a coverall (normal workwear) is a source of potentially significant dermal exposure to polycyclic aromatic hydrocarbons (PAHs) in coal liquefaction workers.

METHODS

An intervention study was conducted over a two week period involving 10 workers that reflected the range of activities performed at the factory. A cross over design was used to examine the influence of normal workwear (personal clothing worn beneath a coverall) and intervention workwear (new coverall, shirt, trousers, underwear, socks, and boots) upon excretion of urinary 1-hydroxypyrene (1-OHP) and skin pad deposition of pyrene.

RESULTS

The impact of intervention was noted in three ways: (1) A notable reduction (55%) in the mass of 1-OHP excreted on the first day of the intervention phase was found. The median reduction in mass excreted (22.7 nmol) was significant from zero at the 5% level; (95% confidence interval (95% CI) 9.5-40.8 nmol). (2) A notable reduction (82%) in skin pad deposition of pyrene on the first day of the intervention phase was found. The median reduction of 13.20 ng.cm-2 was significant from zero at the 5% level; (95% CI 7.3-26.4 ng.cm-2). (3) About a 50% reduction in 1-OHP concentration over the working week occurred during the intervention phase; an increase of 2.07 mumol/mol creatinine was found from the start to the end of the work period during the intervention phase compared with an increase of 4.06 mumol/mol creatinine during the normal phase. This reduction was not significant at the 5% level.

CONCLUSION

The results indicate that on the first day of the working week investigated, significant reductions in absorbtion (as measured by excretion of urinary 1-OHP) and deposition of PAHs (as measured by skin pad deposition of pyrene) can be effected by improvements in workwear policy. The impact of the improved workwear regimen was also detected by reduction in spot urinary 1-OHP concentrations, although this effect was less pronounced. One implication of the findings is that exposure to PAHs may arise from workers' own contaminated personal clothing. As a consequence of this study an improved workwear policy has been implemented at the factory.