Exposure to polycyclic aromatic hydrocarbons assessed by biomonitoring of firefighters during fire operations in Germany

Impact of occupational exposure to wildfire events on systemic inflammatory biomarkers in Portuguese wildland firefighters

While occupational exposure as a firefighter is considered a dangerous occupation, research on the underlying mechanisms remains limited, particularly in wildland firefighters. Inflammation, a key effect of wildfire exposure, plays a significant role in the development of various diseases. The current study aims to investigate the impact of wildland firefighting exposure on the levels of pro-inflammatory systemic biomarkers. A pre-post study design investigated 59 wildland firefighters comparing data collected after participation in a wildfire event (Phase II) with data obtained before wildfire season (Phase I). Data on demographics, lifestyle, health and occupational-related factors were assessed. Exposure factors, such as fire combat (e.g., exposure duration), were also registered. Inflammatory biomarkers (i.e. interleukin-6 [IL-6], interleukin-8 [IL-8], tumor necrosis factor α [TNF-α] and high-sensitivity C-reactive protein [hs-CRP]) and hydroxylated polycyclic aromatic hydrocarbons metabolites (1-OHNaph+1-OHAce, 2-OHFlu, 1-OHPhen, 1-OHPyr) were analysed in blood and urine samples, respectively. Serum IL-8 and IL-6 levels were significantly increased after wildland fire combat. IL-8 levels were 2.62 times higher (95 % CI: 1.96-3.50; p < 0.01), whereas IL-6 levels were 1.25 times higher (95 % CI: 1.00-1.57; p = 0.04). Furthermore, IL-8 levels were significantly correlated with urinary 2-hydroxyfluorene levels and fire combat duration (>12 h). In addition, the mean hs-CRP level, in both phases, was above 3.0 mg/L, indicating a potential risk for cardiovascular events. Given the long-term health implications of firefighting occupational exposure, biomonitoring and early detection of occupational risks are essential for protecting firefighters' health. Protective measures must be urgently implemented to enhance occupational health and strengthen preventive strategies in this sector.

Cotton undergarments as a tool for polycyclic aromatic hydrocarbons whole body dosimetry of firefighters

Firefighters are exposed to a variety of hazardous substances during firefighting activities. Fire smoke contains polycyclic aromatic hydrocarbons (PAHs) some of which have been shown to cause cancer in humans. To assess dermal exposure of firefighters during real-life firefighting, a whole-body dosimetry method was applied to determine the PAH that settles on the skin despite firefighters wearing personal protective equipment (PPE). In total, 17 firefighters wore cotton undergarments (shirts, trousers, gloves, socks, and balaclavas) under their PPE during firefighting missions. After firefighting, fabric pieces were analyzed for 16 US-EPA PAHs and benzo[e]pyrene. Detailed information about the fire missions was solicited from firefighters via a questionnaire. Seventy percent of firefighters provided their undergarments and PAHs were analyzed in 309 punched-out fabric pieces. PAHs were quantified in 27 out of the 309 fabric pieces (8.7%). Generally, PAH concentrations were higher after firefighting in residential buildings compared to exposure levels after fighting vehicle or outdoor fires. Phenanthrene and pyrene were the predominant compounds and were observed up to 657 and 244 ng/g, respectively. Benzo[a]pyrene (B[a]P) was detected in 10 fabric pieces (3.2%) up to 103 ng/g, but all levels were below 1,000 ng/g, the threshold limit of B[a]P according to European Consumer Goods Regulation (European Commission Regulation (EU) 2018/1513). It was demonstrated that firefighting PPE can be an effective shield against dermal exposure to carcinogenic substances. Thus, all measured PAH concentrations in the fabric pieces were below the threshold limit of 1,000 ng/g of each PAH, which is allowed in consumer goods in the European Union for clothing worn on the skin However, individual dermal exposures cannot be completely avoided during firefighting missions. The use of undergarments, gloves, socks, and balaclavas for whole-body dosimetry, which are worn under the PPE, can be useful in assessing whether hazardous substances penetrate the firefighters' PPE.

The role of personal protective equipment (PPE) in reducing firefighter exposure to chemical hazards: A systematic review

This paper aims to investigate the effectiveness of personal protective equipment (PPE) in reducing firefighter exposure to various hazardous chemicals from the smoke emitted during fires. A systematic review of peer-reviewed articles was undertaken utilizing five databases: Medline, Embase, Web of Science, Scopus, and CINHAL. Studies published between 2013 and 2023 that investigated the effectiveness of PPE in reducing firsthand exposure to at least one chemical were included. Extracted data were grouped into two overarching themes related to PPE: (a) Respiratory Protection and (b) Personal Protective Clothing (PPC). Overall, 21 studies met the inclusion criteria and were considered for further analysis. Respiratory protection, particularly self-contained breathing apparatus (SCBA), offered the most protection in preventing inhalation exposure to chemical hazards. There was limited evidence on the effectiveness of firefighter turnout gear in reducing skin contamination. Combustion contaminants, especially highly volatile compounds like benzene, were found to permeate and penetrate through and around the protective clothing. In conclusion, certain respirators, particularly SCBA, provided the best protection against inhalation exposure to chemicals; however, PPC did not appear to provide complete protection, particularly against the more volatile chemicals like benzene.

Online SPE-LC-MS-MS method for eight hydroxylated metabolites of polycyclic aromatic hydrocarbons in urine and determination of optimal sampling time after firefighter training

Polycyclic aromatic compounds (PAHs) are formed during incomplete combustion and firefighters are inadvertently at risk of being exposed to these and other hazardous compounds. Exposure to PAHs is often estimated by measuring their hydroxylated metabolites (OH-PAH) in urine. Here, an online-SPE LC-MS-MS method was set up for eight OH-PAHs thus increasing sample throughput and minimizing manual handling. The method was validated over a 5-month period and showed good reproducibility with intra- and inter-day variation of 2.4-8.1 % and 1.6-6.5 %, respectively, of low-level samples and accuracy (91.6-104.8 %) for a standard reference material. The method was applied to urine samples from conscripts training to become firefighters to determine the optimal sampling time for this training activity before a large intervention study. In total, six conscripts sampled urine 6-8 times over a 40-hr period during a 3-day training course. All eight metabolites were detected in ≥ 97 % of the samples and showed peak excretion 4-6 hrs after the training corresponding to 8-10 hrs after first exposure. Samples taken the morning after the exercise contained low levels of most metabolites. Consequently, 4-6 hrs post exposure is recommended as the optimal sampling time for quantification of PAH exposure and monitoring of potential differences in exposure.

Review of environmental airborne pyrene/benzo[a]pyrene levels from industrial emissions for the improvement of 1-hydroxypyrene biomonitoring interpretation

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants of significant public health concern, with several that are highly toxic to humans, including some proven or suspected carcinogens. To account for the high variability of PAH mixtures encountered in occupational settings, adjusting urinary 1-hydroxypyrene (1-OHP) levels by the total airborne pyrene (PyrT)/benzo[a]pyrene (BaP) ratio is essential for human biomonitoring (HBM). Given the complexity and cost of systematically monitoring atmospheric levels, alternative approaches to simultaneous airborne and HBM are required. The aim of this review was to catalog airborne PyrT/BaP ratios measured during different industrial activities and recommend 1-OHP-dedicated biological guidance values (BGV). A literature search was conducted. Seventy-one studies were included, with 5619 samples pertaining to 15 industrial sectors, 79 emission processes, and 213 occupational activities. This review summarized more than 40 years of data from almost 20 countries and highlighted the diversity and evolution of PAH emissions. PyrT/BaP ratios were highly variable, ranging from 0.8 in coke production to nearly 40 in tire and rubber production. A single PyrT/BaP value cannot apply to all occupational contexts, raising the question of the relevance of defining a single biological limit value for 1-OHP in industrial sectors where the PyrT/BaP ratio variability is high. Based upon the inventory, a practical approach is proposed for systematic PAH exposure and risk assessment, with a simple frame to follow based upon specific 1-OHP BGVs depending upon the occupational context and setup of a free PAH HBM interactive tool.

Biomonitoring of polycyclic aromatic hydrocarbons exposure and short-time health effects in wildland firefighters during real-life fire events

Human biomonitoring data retrieved from real-life wildland firefighting in Europe and, also, worldwide are scarce. Thus, in this study, 176 Portuguese firefighters were biomonitored pre- and post- unsimulated wildfire combating (average:12-13 h; maximum: 55 h) to evaluate the impact on the levels of urinary polycyclic aromatic hydrocarbons hydroxylated metabolites (OHPAH; quantified by high-performance liquid chromatography with fluorescence detection) and the associated short-term health effects (symptoms, and total and differentiated white blood cells). Correlations between these variables and data retrieved from the self-reported questionnaires were also investigated. Firefighters were organized into four groups according to their exposure to wildfire emissions and their smoking habits: non-smoking non-exposed (NSNExp), non-smoking exposed (NSExp), smoking non-exposed (SNExp), and smoking and exposed (SExp). The most abundant metabolites were 1-hydroxynaphthalene and 1-hydroxyacenaphthene (1OHNaph + 1OHAce) (98-99 %), followed by 2-hydroxyfluorene (2OHFlu) (0.2-1.1 %), 1-hydroxyphenanthrene (1OHPhen) (0.2-0.4 %), and 1-hydroxypyrene (1OHPy) (0.1-0.2 %); urinary 3-hydroxybenzo(a)pyrene was not detected. The exposure to wildfire emissions significantly elevated the median concentrations of each individual and total OHPAH compounds in all groups, but this effect was more pronounced in non-smoking (1.7-4.2 times; p ≤ 0.006) than in smoking firefighters (1.3-1.6 times; p ≤ 0.03). The greatest discriminant of exposure to wildfire emissions was 1OHNaph + 1OHAce (increase of 4.2 times), while for tobacco smoke it was 2OHFlu (increase of 10 times). Post-exposure, white blood cells count significantly increased ranging from 1.4 (smokers, p = 0.025) to 3.7-fold (non-smokers, p < 0.001), which was accompanied by stronger significant correlations (0.480 < r < 0.882; p < 0.04) between individual and total OHPAH and total white blood cells (and lymphocytes > monocytes > neutrophils in non-smokers), evidencing the impact of PAH released from wildfire on immune cells. This study identifies Portuguese firefighters with high levels of biomarkers of exposure to PAH and points out the importance of adopting biomonitoring schemes, that include multiple biomarkers of exposure and biomarkers of effect, and implementing mitigations strategies.

Baseline data and associations between urinary biomarkers of polycyclic aromatic hydrocarbons, blood pressure, hemogram, and lifestyle among wildland firefighters

Introduction

Available literature has found an association between firefighting and pathologic pathways leading to cardiorespiratory diseases, which have been linked with exposure to polycyclic aromatic hydrocarbons (PAHs). PAHs are highlighted as priority pollutants by the European Human Biomonitoring Initiative in occupational and non-occupational contexts.

Methods

This cross-sectional study is the first to simultaneously characterize six creatinine-adjusted PAHs metabolites (OHPAHs) in urine, blood pressure, cardiac frequency, and hemogram parameters among wildland firefighters without occupational exposure to fire emissions (> 7 days), while exploring several variables retrieved via questionnaires.

Results

Overall, baseline levels for total OHPAHs levels were 2 to 23-times superior to the general population, whereas individual metabolites remained below the general population median range (except for 1-hydroxynaphthalene+1-hydroxyacenaphtene). Exposure to gaseous pollutants and/or particulate matter during work-shift was associated with a 3.5-fold increase in total OHPAHs levels. Firefighters who smoke presented 3-times higher total concentration of OHPAHs than non-smokers (p < 0.001); non-smoker females presented 2-fold lower total OHPAHs (p = 0.049) than males. 1-hydroxypyrene was below the recommended occupational biological exposure value (2.5 μg/L), and the metabolite of carcinogenic PAH (benzo(a)pyrene) was not detected. Blood pressure was above 120/80 mmHg in 71% of subjects. Firefighters from the permanent intervention team presented significantly increased systolic pressure than those who performed other functions (p = 0.034). Tobacco consumption was significantly associated with higher basophils (p = 0.01-0.02) and hematocrit (p = 0.03). No association between OHPAHs and blood pressure was found. OHPAHs concentrations were positively correlated with monocyte, basophils, large immune cells, atypical lymphocytes, and mean corpuscular volume, which were stronger among smokers. Nevertheless, inverse associations were observed between fluorene and pyrene metabolites with neutrophils and eosinophils, respectively, in non-smokers. Hemogram was negatively affected by overworking and lower physical activity.

Conclusion

This study suggests possible associations between urinary PAHs metabolites and health parameters in firefighters, that should be further assessed in larger groups.

Biomonitoring of polycyclic aromatic hydrocarbons in firefighters at fire training facilities and in employees at respiratory protection and hose workshops

Introduction

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic to humans and are formed by incomplete combustion. PAHs are always present during firefighting operations, and fire department members can be exposed to them in the workplace.

Methods

In this study, we analyzed 1-hydroxypyrene (1-OHP) in 36 urine samples from nine firefighters, collected before and after fire training sessions, and 32 urine samples from eight employees at respiratory protection and hose workshops. To assess breakthrough PAH exposure through personal protective equipment and potential dermal uptake, some of the workshop employees wore cotton garments under their regular workwear. Cotton samples were then examined for the presence of 17 semi-volatile and low-volatility PAHs.

Results

After firefighting exercises, we observed approximately a fivefold increase in mean 1-OHP concentrations in samples from firefighters, from 0.24 μg/L to 1.17 μg/L (maximum: 5.31 μg/L). In contrast, 1-OHP levels in workshop employees were found to be low, with the majority of urine samples yielding concentrations below the limit of quantification (LOQ: 0.05 μg/L, maximum: 0.11 μg/L). Similarly, low PAH levels were found on the workshop employees' cotton undergarments, with maximum concentrations of 250 and 205 ng/g for pyrene and benzo[a]pyrene, respectively.

Discussion

In conclusion, significant increases in 1-OHP in urine were observed in firefighters after training sessions, whereas work-related exposure remained low among workshop employees.

Balancing Acute and Chronic Occupational Risks: The Use of Nitrile Butadiene Rubber Undergloves by Firefighters to Reduce Exposure to Toxic Contaminants

Firefighters are exposed via multi-route exposure to a multitude of chemicals (PAHs, VOCs, flame retardants, dioxins, etc.) that may cause acute and long-term health effects. The dermal absorption of contaminants is a major contributor to the overall exposure and can be reduced by wearing appropriate personal protective equipment. As leather firefighters' gloves cannot be decontaminated regularly by wet cleaning, many Belgian firefighters wear supplementary undergloves made of nitrile butadiene rubber (NBR) to protect against the accumulation of toxicants. However, the safety of this practice has been questioned. In this commentary, the current practice and risks are outlined for the first time, assessed by an interdisciplinary working group of the Belgian Superior Health Council. As NBR sticks to the skin more at high temperatures, the contact time on removal will be prolonged, posing an additional risk for deeper burns. However, based on the physicochemical properties of NBR and the existing experience of firefighters and burn centers, it is estimated that such incidents occur relatively rarely in practice. On the other hand, the risk of repeated exposure to contaminated gloves if no undergloves are worn is unacceptable. Despite the slightly increased risk for deeper burns, it is concluded that wearing disposable NBR gloves under regular firefighters' gloves is an appropriate and effective preventive measure against toxic contamination. The nitrile butadiene rubber must always be fully covered to avoid any contact with the heat.

Impact of diesel exhaust exposure on urinary 1-hydroxypyrene in underground salt and potash workers

BACKGROUND

Diesel engine exhaust (DEE) and some of the polycyclic aromatic hydrocarbons (PAH) it contains are carcinogenic to humans (for example benzo(a)pyrene) and can cause lung cancer in workers. The objective of this study was to assess exposures to DEE and its component PAH and the potential associations between these two health hazards in a salt and potash mining population.

METHODS

Between 2017 and 2019, 1003 underground workers (mining n = 801, maintenance n = 202) and 243 above-ground facility workers from two German mines participated. Personal exposure to DEE was assessed in air as elemental carbon for diesel particulate matter (EC-DPM), whereas exposure to PAH was assessed in pre- and post-shift urine samples in terms of 1-hydroxypyrene (1-OHP). Associations between EC-DPM and 1-OHP were studied using linear regression models.

RESULTS

The highest EC-DPM exposures were measured in mining workers (median 0.06 mg/m³) followed by workers in the maintenance (0.03 mg/m³) and facility areas (<0.02 mg/m³). Exposures above the current German occupational threshold level of 0.05 mg/m³ were observed in 56%, 17%, and 5% of mining, maintenance and facility workers, respectively. 1-OHP increased statistically significantly across a work shift in underground workers but not in facility workers. Regression analyses revealed an increase of post-shift 1-OHP by almost 80% in mining and 40% in maintenance compared with facility workers. 1-OHP increased with increasing EC-DPM among underground workers. However, internal exposure of 1-OHP mainly remained at levels similar to those of the German general population in more than 90% of the urine samples.

CONCLUSIONS

While exposures to DEE above the current German OEL for EC-DPM are quite common in the studied population of underground salt and potash miners (39.5% overall), urinary concentrations of 1-OHP did not reflect these findings.