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Firefighters’ Occupational Exposure in Preparation for Wildfire Season: Addressing Biological Impact

Publication . Esteves, Filipa; Slezakova, Klara; Madureira, Joana; Vaz, Josiana A.; Fernandes, Adília; Morais, Simone; Pereira, Maria do Carmo; Teixeira, João Paulo Fernandes; Costa, Solange

The characterization of wildland firefighters' occupational exposure must consider different exposures, including those at the fire station. The present study aimed to characterize the occupational exposure of 172 Northern Portuguese wildland firefighters in fire stations during the pre-wildfire season of 2021. The biological impact of estimated inhaled doses of PM10 and PM2.5 (indoor/outdoor) was accessed through a buccal micronucleus cytome (BMCyt) assay in exfoliated buccal cells of a subgroup of 80 firefighters. No significant association was found between estimated inhaled doses of PM10 and PM2.5 (mean 1.73 +/- 0.43 mu g kg-1 and 0.53 +/- 0.21 mu g kg-1, respectively) and biological endpoints. However, increased frequencies of cell death parameters were found among subjects of the Permanent Intervention Teams (full-time firefighters). The intake of nutritional supplements was associated with a significant decrease in micronucleus frequencies (i.e., DNA damage or chromosome breakage). In addition, our findings showed a significantly increased frequency of cell death endpoints (i.e., nuclear fragmentation) with coffee consumption, while daily consumption of vegetables significantly decreased it (i.e., nuclear shrinkage). Our results provide data on the occupational exposure of wildland firefighters while working in fire stations during the pre-wildfire season, providing the essential baseline for further studies throughout the wildfire season.

2024Journal article

Open access

Occupational exposure to wildland firefighting and its effects on systemic DNA damage

Publication . Esteves, Filipa; Madureira, Joana; Costa, Carla Sofia; Pires, Joana; Barros, Bela; Alves, Sara; Vaz, Josiana A.; Oliveira, Marta; Slezakova, Klara; Fernandes, Adília; Pereira, Maria do Carmo; Morais, Simone; Valdiglesias, Vanessa; Bonassi, Stefano; Teixeira, João Paulo; Costa, Solange

Portugal is among the European Union countries more devastated by forest fires. Wildland fire- fighters are at the forefront of this battle, facing exposure to a wide range of harmful pollutants. Epidemiological studies have highlighted a potential link between occupational firefighting exposure and several diseases, including cancer. To date, very few studies have explored the biological mechanisms associated with such exposure. The present longitudinal study aims to assess changes in early effect biomarkers following wildland firefighters’ occupational exposure to a real wildfire event. Paired blood samples from 59 healthy Portuguese wildland firefighters were collected at two different time points: before wildfire season and after a fire event during wildfire season. Sociodemographic variables (e. g., age, sex) and work-related factors (e.g., years of service) were assessed via a self-reported questionnaire. Levels of early effect biomarkers, such as primary DNA damage and oxidative DNA damage (oxidised purines) were assessed via comet assay. DNA double-strand breaks (DSBs) were evaluated by phosphorylated H2AX (γH2AX). Moreover, hydroxylated polycyclic aromatic hydrocarbon metabolites (OHPAHs) and metal(loid)s were quantified in urine samples. The influence of urinary OHPAHs, urinary metal(loid)s, and other exposure- related factors (e.g., firefighting duration) on changes (Δ) in early effect biomarkers (post-vs. baseline levels) was investigated. Firefighting activities led to a significant increase in both primary DNA damage and oxidative DNA damage by 22 % (95 % CI: 1.11–1.35; p < 0.05) and 23 % (95 % CI: 1.04–1.45; p < 0.05), respectively. Results from linear regression revealed that per each unit increase of urinary 2-hydroxyfluorene (2-OHFlu) (μmol/mol creatinine), the risk of ⧍ oxidative DNA damage increased by 20 % [FR: 1.20 (1.09–1.32); p < 0.01]. Addi- tionally, each unit increase in urinary cesium (Cs) (μg/L) resulted in a significant 4 % increase in Δ primary DNA damage [FR: 1.04 (1.01–1.06); p < 0.05] and a 3 % increase in Δ oxidative DNA damage [FR: 1.03 (1.01–1.05); p < 0.05]. Post-exposure levels of γH2AX were significantly correlated with urinary 2-OHFlu levels assessed after firefighting (r = 0.30; p < 0.05). Furthermore, exposure duration and reported breathing difficulties during firefighting were significantly associated with increased levels of primary DNA damage. Results obtained provide insights into the potential human health effects of wildland firefighting occupational exposure at the genetic and molecular levels, offering new and important mechanistic data. These findings are crucial for implementing health and safety measures, recommendations, and best practices to mitigate occupational risks and protect the health of wildland firefighters.

2025Journal article

Open access