Inhal Toxicol

Background: Wildland firefighters conducting prescribed burns are exposed to a complex mixture of pollutants, requiring an integrated measure of exposure. Objective: We used urinary mutagenicity to assess if systemic exposure to mutagens are higher in firefighters after working at prescribed burns versus after non-burn work days. Other biomarkers of exposure and oxidative stress markers were also measured. Methods: Using a repeated measures study design, we collected urine before, immediately after, and the morning after a work shift on prescribed burn and non-burn work days from 12 healthy subjects. Urines were analyzed for malondialdehyde (MDA), 8-isoprostane, 1-hydroxypyrene (OH-Pyrene), and mutagenicity in Salmonella YG1041 +S9. Particulate matter (PM2.5) and carbon monoxide (CO) measurements were collected by personal monitoring. Light-absorbing carbon (LAC) of PM2.5 was measured as a surrogate for black carbon exposure. Linear mixed-effect models were used to assess cross-work shift (pre- to post-work shift) changes in urinary biomarkers. Results: No significant differences occurred in creatinine-adjusted urinary mutagenicity across the work shift between burn days (48 samples) and non-burn day (21 samples). Firefighters lighting fires had a non-significant, 1.6-fold increase in urinary mutagenicity for burn- versus non-burn day exposures. Positive associations were found between cross-work shift (pre- to post-) changes in creatinine-adjusted urinary mutagenicity and MDA (p = 0.0010), OH-Pyrene (p = 0.0001), and mass absorption efficiency, which is the LAC/PM2.5 ratio (p = 0.2245), respectively. No significant effect of day type or work task on cross-work shift (pre- to post-) changes in MDA or 8-isoprostane was observed. Conclusion: Urinary mutagenicity may serve as a suitable measure of occupational smoke exposures among wildland firefighters, especially among those lighting fires for prescribed burns.

30985217

PMC6624838

Journal Article

CDC Public Access