Objective Wildland firefighters (WLFFs) experience repeated exposures to wildland fire smoke (WFS). However, studies about WLFFs remain regionally limited. The objective of this study was to assess the effect of WFS exposure on urinary mutagenicity and cell oxidation among WLFFs who work at prescribed burns in the Midwestern USA.
Methods A total of 120 spot urine samples was collected from 19 firefighters right before (pre-shift), immediately after (post-shift), and the morning (next-morning) following work shifts on prescribed burn days (burn days) and regular workdays (non-burn days). The levels of urinary mutagenicity, 8-isoprostane, malondialdehyde and oxidised guanine species (Ox-GS) were measured. Linear mixed-effect models were used to determine the difference of cross-shift changes in the concentrations of urinary biomarkers.
Results Post-shift levels of creatinine-corrected urinary mutagenicity and 8-isoprostane were non-significantly higher than pre-shift levels (1.16× and 1.64×; p=0.09 and 0.07) on burn days. Creatinine-corrected Ox-GS levels increased significantly in next-morning samples following WFS exposure (1.62×, p=0.03). A significant difference in cross-shift changes between burn and non-burn days was observed in 8-isoprostane (2.64×, p=0.03) and Ox-GS (3.00×, p=0.02). WLFFs who contained the fire (performed holding tasks) had a higher pre-morning to next-morning change in urinary mutagenicity compared with those who were lighting fires during the prescribed burns (1.56×, p=0.03).
Conclusions Compared with the other regions, WLFFs who worked in Midwestern forests had an elevated urinary mutagenicity and systemic oxidative changes associated with WFS exposure at prescribed burns.
- biological monitoring
- occupational health
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Contributors OA and C-MW obtained research funding, designed the study, recruited wildland firefighters and collected spot urine samples. C-MW also performed biochemical and statistical analyses with the advice from OA and CS. DMD and SHW performed urinary mutagenicity using the Salmonella (Ames) mutagenicity assay. The final manuscript was prepared by C-MW and critically revised by the coauthors.
Funding This study was supported by: (1) the Grant or Cooperative Agreement Number, T42-OH008455, funded by the Centers for Disease Control and Prevention. (2) Alumni Grants for Graduate Research and Scholarship (AGGRS) at The Ohio State University. The organic extractions and urinary mutagenicity experiments were performed at the US Environmental Protection Agency, Research Triangle Park, North Carolina, and supported by the intramural research program of the Office of Research and Development of the US EPA, Research Triangle Park, North Carolina.
Disclaimer The paper contents are solely the responsibility of the authors and do not necessarily represent the official views of the Centers for Disease Control and Prevention or the Department of Health and Human Services. This paper has been reviewed and approved for publication by the Center for Computational Toxicology and Exposure, Office of Research and Development, US Environmental Protection Agency. Approval does not signify that the contents necessarily reflect the views and policies of the US EPA, nor does mention of trade names or commercial products constitute endorsement or recommendation of use.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The protocol was reviewed and approved by The Ohio State University Institutional Review Board (2017H0075). Informed consent was obtained from each participant prior to their enrolment.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request. De-identified data are available upon request to the corresponding author (firstname.lastname@example.org).
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