Wu Chieh-Ming, Warren Sarah H, DeMarini David M, Song Chi Chuck, Adetona Olorunfemi
College of Public Health, Division of Environmental Health Sciences, The Ohio State University, Columbus, Ohio, USA.
Biomolecular and Computational Toxicology Division, United States Environmental Protection Agency, Research Triangle Park, North Carolina, USA.
Occup Environ Med. 2020 Nov 2. doi: 10.1136/oemed-2020-106612.
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.
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.
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).
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.
野外消防员（WLFFs）会反复接触野外火灾烟雾（WFS）。然而，关于野外消防员的研究在地域上仍有局限性。本研究的目的是评估在美国中西部进行规定火烧作业的野外消防员接触WFS对尿液致突变性和细胞氧化的影响。
在规定火烧日（火烧日）和正常工作日（非火烧日）的工作班次前（班前）、工作班次后立即（班后）以及工作班次后的早晨（次晨），从19名消防员中总共收集了120份即时尿样。测量了尿液致突变性、8-异前列腺素、丙二醛和氧化鸟嘌呤物种（Ox-GS）的水平。使用线性混合效应模型来确定尿液生物标志物浓度跨班次变化的差异。
在火烧日，班后经肌酐校正的尿液致突变性和8-异前列腺素水平比班前水平略高（分别为1.16倍和1.64倍；p = 0.09和0.07），差异无统计学意义。经肌酐校正的Ox-GS水平在接触WFS后的次晨样本中显著升高（1.62倍，p = 0.03）。在8-异前列腺素（2.64倍，p = 0.03）和Ox-GS（3.00倍，p = 0.02）方面，观察到火烧日和非火烧日的跨班次变化存在显著差异。与在规定火烧期间点火的消防员相比，控制火势（执行控制任务）的野外消防员尿液致突变性从班前到次晨的变化更高（1.56倍，p = 0.03）。
与其他地区相比，在美国中西部森林工作的野外消防员在规定火烧时接触WFS会导致尿液致突变性升高和全身氧化变化。
