Inflammatory Effects of Woodsmoke Exposure Among Wildland Firefighters Working at Prescribed Burns at the Savannah River Site, SC

Abstract

Wildland firefighters in the United States are occupationally exposed to high levels of woodsmoke. Results from experimental studies show that exposure to woodsmoke induces inflammation. A study was conducted to investigate the effect of occupational woodsmoke exposure on inflammatory biomarkers in firefighters working at prescribed burns. Twelve U.S. Forest Service wildland firefighters at the Savannah River Site, South Carolina, volunteered to give blood samples during four prescribed burns between February and March 2011. Twenty-four paired (pre- and post-work shift) blood samples were collected using dried blood spot method to facilitate repeated sample collection. Inflammatory biomarker concentrations in blood samples were measured using the Meso Scale Discovery multi-spot assay system. Concurrent personal PM_2.5 and CO monitoring of firefighters was conducted. Linear mixed models were used to test whether cross-work shift differences occurred in the following inflammatory biomarkers: IL-1β, IL-8, CRP, SAA, ICAM-1, and VCAM-1. IL-8 showed a significant cross-work shift difference as indicated by a post/pre-work shift ratio of 1.70 (95% CL: 1.35, 2.13; p = 0.0012). Concentrations of IL-8, CRP, and ICAM-1 increased in >50% of samples across work shift. Firefighters who lighted fires as opposed to other work tasks had the largest cross-work shift increase in IL-8. A significant cross-work shift increase in IL-8 in blood samples was observed in healthy wildland firefighters working at prescribed burns. Further research is needed to understand the physiological responses underlying the adverse effects of woodsmoke exposure, and the dose-response relationship between woodsmoke exposure and inflammatory responses.

Keywords:

• dried blood spot
• inflammation
• interleukin-8
• prescribed burns
• wildland firefighters
• woodsmoke

ACKNOWLEDGMENTS

Funding and support was by the U.S. Forest Service (USFS) Savannah River - Interagency Agreement DE-AI09–00SR 22188 (project number H2001–10311-5) and the National Institute of Occupational Safety and Health Education Research Center (NIOSH/ERC) Small Project/Pilot Study Grants via the University of Alabama at Birmingham (UAB) (grant numbers 2T42OH008436 and 2T42OH008436-03 awarded in 2010 and 2011, respectively).

Sincere appreciation goes to Paul Varnedoe, Chris Hobson, John Blake, and the USFS-SR crew who participated in the study. The research described in this article has been reviewed by the National Health and Environmental Effects Research Laboratory, U.S. EPA, and approved for publication.  The contents of this article should not be construed to represent Agency policy nor does mention of trade names or commercial products constitute endorsement or recommendation for use.