Biomonitoring of Wildland Firefighters: Analysis of Methoxyphenols as Viable Urinary Biomarkers of Wood Smoke Exposure

Occupational exposures to wood smoke can lead to a multitude of health effects, making it a pertinent issue of public health. Biomass in the form of wood smoke can lead to adverse health effects including respiratory impairment, asthma, cardiovascular disease, and increased mortality, especially with people who are immune-compromised. Wildland firefighters comprise a group that faces much higher exposures to wood smoke than other groups, making them a candidate for further understanding wood smoke exposure and its potential for health effects. Biomonitoring involves utilizing biomarkers of exposure as a means for quantifying the dose-response exposure relationship with other more harmful compounds. One of the compound groups that is specific to wood smoke are methoxyphenol compounds, which are formed during the pyrolysis of lignin. By measuring biomarkers of wood smoke exposure, the ambient concentration of wood smoke can be determined. This study investigated the dose-response relationship of wood smoke exposure and concentrations of urinary methoxyphenol compounds, specifically guaiacols and syringols in wildland firefighters to determine if methoxyphenol compounds could serve as suitable biomarkers of wood smoke exposure. Full-shift personal exposure monitoring of USFS wildland firefighters at the USDS Savannah River Site in South Carolina occurred during the dormant burn season of spring 2008 and spring 2009. There were a total of 155 person-day samples collected over 32 days during the study. Urine samples were analyzed at the University of Washington for creatinine and 13 methoxyphenol compounds. The results indicated that the eight-hour TWA for CO exposure was the most representative exposure variable based on high Pearson's correlation values with other exposure variables and urinary methoxyphenols. Propylguaiacol was the most representative methoxyphenol compound for this dataset. The regression results indicate an association exists between CO and post-shift concentrations of propylguaiacol. Further, cross-shift concentrations of propylguaiacol also were associated with the eight-hour CO TWA as an exposure variable. Future studies hope to investigate subject-specific differences in urinary methoxyphenol concentrations.