Urinary levoglucosan as a biomarker for woodsmoke exposure in wildland firefighters

Background: Levoglucosan, a sugar anhydride and a combustion breakdown product of cellulose is a dominant organic constituent of particles in woodsmoke. After exposure, levoglucosan is excreted unmetabolized in urine. Objective: Urinary levoglucosan was assessed as a biomarker of occupational woodsmoke exposure among wildland firefighters. Methods: Urine samples were collected from wildland firefighters before and after their work-shifts on days when they worked at prescribed burns. A total of 97 pairs of pre- and post-shift urine samples were collected from 19 firefighters over 10 prescribed burn shifts. The urine samples were analyzed to determine whether there was an increase in the concentration of levoglucosan from pre-to post-shift after the firefighters had worked at the prescribed burns. Results: Overall, there was an increase in both the urinary volume-based and creatinine corrected levoglucosan concentrations from pre- to post-shift (P < 0.05). However, the direction of change in the concentrations was not consistent. There were increases in urinary levoglucosan concentration from pre-to post-shift in 63% of the person-day samples, and in only 58% of the person-day samples for the creatinine corrected concentrations. Conclusion: Although there was an overall increase in urinary concentrations of levoglucosan, results suggest that other sources apart from woodsmoke affected the urinary levels of this biomarker in wildland firefighters. Therefore, urinary levoglucosan may not be effective as a biomarker of woodsmoke exposure in this setting.