Organophosphate flame retardants in dust collected from United States fire stations

Association of co-exposure to organophosphate esters and per- and polyfluoroalkyl substances and mixture with cardiovascular-kidney-liver-metabolic biomarkers among Chinese adults

BACKGROUND

Organophosphate esters (OPEs) and Per- and polyfluoroalkyl substances (PFAS) are ubiquitous environmental contaminants with common exposure sources, leading to their widespread presence in human body. However, evidence on co-exposure to OPEs and PFAS and its impact on cardiovascular-kidney-liver-metabolic biomarkers remains limited.

METHODS

In this cross-sectional study, 467 adults were enrolled from January to May 2022 during physical visits in Shijiazhuang, Hebei province. Eleven types of OPEs and twelves types of PFAS were detected, among which eight OPEs and six PFAS contaminants were detected in more than 60% of plasma samples. Seventeen biomarkers were assessed to comprehensively evaluate the cardiovascular-kidney-liver-metabolic function. Multiple linear regression, multipollutant models with sparse partial least squares, and Bayesian kernel machine regression (BKMR) models were applied to examine the associations of individual OPEs and PFAS and their mixtures with organ function and metabolism, respectively.

RESULTS

Of the over 400 exposure-outcome associations tested when modelling, we observed robust results across three models that perfluorohexanoic acid (PFHxS) was significantly positively associated with alanine aminotransferase (ALT), aspartate aminotransferase (AST), total bilirubin (TBIL), and indirect bilirubin (IBIL). Perfluorononanoic acid was significantly associated with decreased AST/ALT and increased very-low-density lipoprotein cholesterol levels. Besides, perfluorodecanoic acid was correlated with increased high lipoprotein cholesterol and perfluoroundecanoic acid was consistently associated with lower glucose level. BKMR analysis showed that OPEs and PFAS mixtures were positively associated with IBIL and TBIL, among which PFHxS was the main toxic chemicals.

CONCLUSIONS

Our findings suggest that exposure to OPEs and PFAS, especially PFHxS and PFNA, may disrupt organ function and metabolism in the general population, providing insight into the potential pathophysiological mechanisms of OPEs and PFAS co-exposure and chronic diseases.

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.

Trends in flame retardant levels in upholstered furniture and children's consumer products after regulatory action in California

In 2013, California revised its upholstered furniture flammability standard TB 117-2013 to improve fire safety without the need for flame retardant (FR) chemicals. Subsequent legislation (SB 1019) required disclosure of FR content. In 2020 California expanded restriction on FR chemicals to include juvenile products and upholstered furniture (AB 2998). To monitor trends in FR use, and assess the effectiveness of the new regulations, we analyzed 346 samples from upholstered furniture (n = 270) and children's consumer products (n = 76), collected pre- and post-regulatory intervention for added FR chemicals (i.e., ∑FR > 1000 mg/kg). Upholstered furniture samples, collected from products before enactment of the new regulations, had a median FR concentration of 41,600 mg/kg (range: 1360-92,900 mg/kg), with 100% of the foam samples and 13.7% of the textile samples containing ∑FR > 1000 mg/kg. Firemaster formulations (FM 550 and FM 600), a mixture of triphenyl phosphate (TPHP), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (BEH-TEBP) and a mixture of isopropyl- or tert-butyl-triphenyl phosphates (ITPs or TBPPs), were the most frequently detected FR (34%), followed by tris(1,3-dichloroisopropyl) phosphate (TDCIPP; 25%), TPHP with a mixture of polybrominated diphenyl ethers (BDE-47, 99, 100, 153 and 154; 20%) and tris(2-chloroethyl) phosphate (TCEP; 11%). Upholstered furniture components collected after enactment of the new legislation had a median FR concentration of 2600 mg/kg (range: 1160-49,800 mg/kg, outlier sample 282,200 mg/kg), with 11.9% of the foam samples and no textile samples containing ∑FR > 1000 mg/kg. Of these samples, tris(1-chloro-2-propyl) phosphate (TCIPP) was the most frequently detected FR (55%), followed by TDCIPP (30%) and Firemaster (FM 550, 15%). No PBDEs were detected in the post-regulatory intervention products. Our initial work on children's products showed 15% of the samples contained ∑FR > 1000 mg/kg. In our post- AB 2998 work, no regulated children's product components failed compliance (i.e., ∑FR > 1000 mg/kg). The data confirm successful adoption of the new regulations with most samples in compliance, demonstrating the efficacy of regulatory intervention. Given these results, environmental FR exposure is expected to decrease as older FR treated consumer products are replaced with FR free products.

Air pollution inside fire stations: State-of-the-art and future challenges

Firefighters are frequently exposed to products of combustion and pyrolysis. Exposure to these substances occurs not only during fires but also at fire stations, particularly where fire equipment and fire uniforms are stored after firefighting operations. The aims of this study were to review the research on the concentrations of various air pollutants in fire stations, identify the limitations and strengths of such research, identify research gaps and related future challenges, and highlight potential solutions for reducing firefighter exposure to air pollution at fire stations. A total of 32 articles published in international journals during 1987-2023 were selected for analysis. The most frequently studied pollutants in fire stations were polycyclic aromatic hydrocarbons, particulate matter, and diesel particulate matter. Research was most often conducted on changing rooms and garages. Firefighting equipment, personal protective equipment, fire trucks, and combustion tools were identified as the main sources of pollution at fire stations. Recommendations aimed at reducing the concentration of pollutants in fire stations were mainly concerned with the systematic decontamination of equipment and the introduction of ventilation solutions that would remove exhaust fumes from garages. This in-depth literature review indicates a lack of comprehensive research on the state and quality of air at fire stations. It also highlights the emerging need for more knowledge on the concentrations of air pollutants in fire stations, health exposure related to these substances, and an analysis of the effectiveness of the proposed solutions.

Urinary concentrations of organophosphate esters and associated health outcomes in Korean firefighters

Although firefighters are at an increased risk of occupational exposure to chemicals, such as flame retardants, research on the exposure of Korean firefighters to organophosphate esters (OPEs)-a group of emerging flame retardants-remains limited. Therefore, in the present study, OPE metabolite concentrations in the urine samples of 149 former and current Korean firefighters were measured. Based on the data obtained, the estimated daily intakes (EDIs) of OPEs were calculated. Subsequently, the association between the urinary concentrations of OPE metabolites and the potential determinants of OPE exposure and health outcomes (e.g., obesity and serum lipids) was investigated. We found that bis(1-chloro-2-propyl) phosphate (BCIPP) and bis(2-chloroethyl) phosphate (BCEP) were the most prevalent urinary OPE metabolites, with median concentrations of 2.33 and 1.80 ng/mL, respectively; these concentrations were higher than those reported previously in other countries, such as the USA and China. Moreover, their parent compounds-tris(1-chloro-2-propyl) phosphate (TCIPP) and tris(2-chloroethyl) phosphate (TCEP)-exhibited EDIs of 126 and 94.8 ng/kg bw/day, respectively. Unlike the high detection rate of bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) in other populations, its detection rate in this study was low (6.7%), suggesting regional differences in the exposure pattern of OPEs among countries. Furthermore, occupational characteristics, such as recent participation in firefighting activity, were identified as determinants of the urinary concentrations of OPE metabolites. Total OPE metabolites were inversely associated with body mass index and positively associated with high-density lipoprotein cholesterol. Overall, our findings demonstrate that Korean firefighters are highly exposed to several occupation-related OPEs. Further prospective studies will help elucidate the potential health implications of occupational exposure to OPEs among firefighters.

Translating community-based participatory research into broadscale sociopolitical change: insights from a coalition of women firefighters, scientists, and environmental health advocates

BACKGROUND

We report on community-based participatory research (CBPR) initiated by women firefighters in order to share successful elements that can be instructive for other community-engaged research. This CBPR initiative, known as the Women Worker Biomonitoring Collaborative (WWBC) is the first we are aware of to investigate links between occupational exposures and health outcomes, including breast cancer, for a cohort of exclusively women firefighters.

METHODS

In order to be reflective of the experiences and knowledge of those most intimately involved, this article is co-authored by leaders of the research initiative. We collected leaders' input via recorded meeting sessions, emails, and a shared online document. We also conducted interviews (N = 10) with key research participants and community leaders to include additional perspectives.

RESULTS

Factors contributing to the initiative's success in enacting broadscale social change and advancing scientific knowledge include (1) forming a diverse coalition of impacted community leaders, labor unions, scientists, and advocacy organizations, (2) focusing on impacts at multiple scales of action and nurturing different, yet mutually supportive, goals among partners, (3) adopting innovative communication strategies for study participants, research partners, and the broader community, (4) cultivating a prevention-based ethos in the scientific research, including taking early action to reduce community exposures based on existing evidence of harm, and (5) emphasizing co-learning through all the study stages. Furthermore, we discuss external factors that contribute to success, including funding programs that elevate scientist-community-advocacy partnerships and allow flexibility to respond to emerging science-policy opportunities, as well as institutional structures responsive to worker concerns.

CONCLUSIONS

While WWBC shares characteristics with other successful CBPR partnerships, it also advances approaches that increase the ability for CBPR to translate into change at multiple levels. This includes incorporating partners with particular skills and resources beyond the traditional researcher-community partnerships that are the focus of much CBPR practice and scholarly attention, and designing studies so they support community action in the initial stages of research. Moreover, we emphasize external structural factors that can be critical for CBPR success. This demonstrates the importance of critically examining and advocating for institutional factors that better support this research.

Biomonitoring of firefighting forces: a review on biomarkers of exposure to health-relevant pollutants released from fires

Occupational exposure as a firefighter has recently been classified as a carcinogen to humans by International Agency for Research on Cancer (IARC). Biomonitoring has been increasingly used to characterize exposure of firefighting forces to contaminants. However, available data are dispersed and information on the most relevant and promising biomarkers in this context of firefighting is missing. This review presents a comprehensive summary and critical appraisal of existing biomarkers of exposure including volatile organic compounds such as polycyclic aromatic hydrocarbons, several other persistent other organic pollutants as well as heavy metals and metalloids detected in biological fluids of firefighters attending different fire scenarios. Urine was the most characterized matrix, followed by blood. Firefighters exhaled breath and saliva were poorly evaluated. Overall, biological levels of compounds were predominantly increased in firefighters after participation in firefighting activities. Biomonitoring studies combining different biomarkers of exposure and of effect are currently limited but exploratory findings are of high interest. However, biomonitoring still has some unresolved major limitations since reference or recommended values are not yet established for most biomarkers. In addition, half-lives values for most of the biomarkers have thus far not been defined, which significantly hampers the design of studies. These limitations need to be tackled urgently to improve risk assessment and support implementation of better more effective preventive strategies.

Hierarchy of contamination control in the fire service: Review of exposure control options to reduce cancer risk

The international fire service community is actively engaged in a wide range of activities focused on development, testing, and implementation of effective approaches to reduce exposure to contaminants and the related cancer risk. However, these activities are often viewed independent of each other and in the absence of the larger overall effort of occupational health risk mitigation. This narrative review synthesizes the current research on fire service contamination control in the context of the National Institute for Occupational Safety and Health (NIOSH) Hierarchy of Controls, a framework that supports decision making around implementing feasible and effective control solutions in occupational settings. Using this approach, we identify evidence-based measures that have been investigated and that can be implemented to protect firefighters during an emergency response, in the fire apparatus and at the fire station, and identify several knowledge gaps that remain. While a great deal of research and development has been focused on improving personal protective equipment for the various risks faced by the fire service, these measures are considered less effective. Administrative and engineering controls that can be used during and after the firefight have also received increased research interest in recent years. However, less research and development have been focused on higher level control measures such as engineering, substitution, and elimination, which may be the most effective, but are challenging to implement. A comprehensive approach that considers each level of control and how it can be implemented, and that is mindful of the need to balance contamination risk reduction against the fire service mission to save lives and protect property, is likely to be the most effective.

Disposition of Fluorine on New Firefighter Turnout Gear

Firefighter turnout gear is essential for reducing occupational exposure to hazardous chemicals during training and fire events. Per-and polyfluoroalkyl substances (PFASs) are observed in firefighter serum, and possible occupational sources include the air and dust of fires, aqueous film-forming foam, and turnout gear. Limited data exist for nonvolatile and volatile PFASs on firefighter turnout gear and the disposition of fluorine on the individual layers of turnout gear. Further implications for exposure to fluorine on turnout gear are not well understood. Three unused turnout garments purchased in 2019 and one purchased in 2008, were analyzed for 50 nonvolatile and 15 volatile PFASs by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-qTOF-MS) and gas chromatography-mass spectrometry (GC-MS), respectively. Particle-induced gamma ray emission (PIGE), a surface technique, and instrumental neutron activation analysis (INAA), a bulk technique, were used to measure total fluorine. Bulk characterization of the layers by pyrolysis-GC/MS (py-GC/MS) was used to differentiate fluoropolymer (e.g., PTFE) films from textile layers finished with side-chain polymers. The outer layer, moisture barrier, and thermal layers of the turnout gear all yielded measured concentrations of volatile PFASs that exceeded nonvolatile PFAS concentrations, but the summed molar concentrations made up only a small fraction of total fluorine (0.0016-6.7%). Moisture barrier layers comprised a PTFE film, as determined by py-GC-MS, and gave the highest individual nonvolatile (0.159 mg F/kg) and volatile PFAS (20.7 mg F/kg) as well as total fluorine (122,000 mg F/kg) concentrations. Outer and thermal layers comprised aromatic polyamide-based fibers (aramid) treated with side-chain fluoropolymers and had lower levels of individual nonvolatile and volatile PFASs. Equal concentrations of total fluorine by both PIGE and INAA on the outer and thermal layers is consistent with treatment with a side-chain fluoropolymer coating. New turnout gear should be examined as a potential source of firefighter occupational exposure to nonvolatile and volatile PFASs in future assessments.

Organophosphate and Organohalogen Flame-Retardant Exposure and Thyroid Hormone Disruption in a Cross-Sectional Study of Female Firefighters and Office Workers from San Francisco

Occupational exposures to flame retardants (FRs), a class of suspected endocrine-disrupting compounds, are of health concern for firefighters. We sought to characterize exposure to FR compounds and evaluate their association with thyroid hormone levels, a biomarker of early effect, in female firefighters and office workers in San Francisco. In a cross-sectional study, we measured replacement organophosphate and organohalogen FRs in spot urine samples from firefighters (N = 86) and office workers (N = 84), as well as total thyroxine (T4) and thyroid-stimulating hormone in plasma for 84 firefighters and 81 office workers. Median bis(1,3-dichloro-2-propyl)phosphate (BDCPP) levels were 5 times higher in firefighters than office workers. Among firefighters, a doubling of BDCPP was associated with a 2.88% decrease (95% confidence interval -5.28, -0.42) in T4. We did not observe significant associations between FRs and T4 among office workers. In the full group, intermediate body mass index and a college education were associated with higher FR levels. The inverse association observed between FRs and T4 coupled with the lack of studies on women workers and evidence of adverse health effects from FR exposure─including endocrine disruption and breast cancer risk─warrant further research on occupational exposures and identification of opportunities for exposure reduction.

A review on organophosphate flame retardants in the environment: Occurrence, accumulation, metabolism and toxicity

Organophosphate flame retardants (OPFRs), as a substitute for brominated flame retardants (BFRs), are widely used in industrial production and life. The presence of OPFRs in the environment has an adverse effect on the ecological environment system. This review provides comprehensive data for the occurrence of OPFRs and their diester metabolites (OP diesters) in wastewater treatment plants, surface water, drinking water, sediment, soil, air and dust in the environment. In particular, the accumulation and metabolism of OPFRs in organisms and the types of metabolites and metabolic pathways are discussed for animals and plants. In addition, the toxicity of OP triesters and OP diesters in organisms is discussed. Although research on OPFRs has gradually increased in recent years, there are still many gaps to be filled, especially for metabolic and toxicity mechanisms that need in-depth study. This review also highlights the shortcomings of current research and provides suggestions for a basis for future research on OPFRs.

Associations between polyfluoroalkyl substance and organophosphate flame retardant exposures and telomere length in a cohort of women firefighters and office workers in San Francisco

BACKGROUND

Environmental chemical exposures can affect telomere length, which in turn has been associated with adverse health outcomes including cancer. Firefighters are occupationally exposed to many hazardous chemicals and have higher rates of certain cancers. As a potential biomarker of effect, we assessed associations between chemical exposures and telomere length in women firefighters and office workers from San Francisco, CA.

METHODS

We measured serum concentrations of polyfluoroalkyl substances (PFAS), urinary metabolites of flame retardants, including organophosphate flame retardants (OPFRs), and telomere length in peripheral blood leukocytes in women firefighters (N = 84) and office workers (N = 79) who participated in the 2014-15 Women Workers Biomonitoring Collaborative. Multiple linear regression models were used to assess associations between chemical exposures and telomere length.

RESULTS

Regression results revealed significant positive associations between perfluorooctanoic acid (PFOA) and telomere length and perfluorooctanesulfonic acid (PFOS) and telomere length among the whole cohort. Models stratified by occupation showed stronger and more significant associations among firefighters as compared to office workers. Among firefighters in models adjusted for age, we found positive associations between telomere length and log-transformed PFOA (β (95%CI) = 0.57(0.12, 1.02)), PFOS (0.44 (0.05, 0.83)), and perfluorodecanoic acid (PFDA) (0.43 (0.02, 0.84)). Modeling PFAS as categories of exposure showed significant associations between perfluorononanoic acid (PFNA) and telomere length among firefighters. Significant associations between OPFR metabolites and telomere length were seen for bis (1,3-dichloro-2-propyl) phosphate (BDCPP) and telomere length among office workers (0.21(0.03, 0.40)) and bis (2-chloroethyl) phosphate (BCEP) and telomere length among firefighters (- 0.14(- 0.28, - 0.01)). For OPFRs, the difference in the direction of effect by occupational group may be due to the disparate detection frequencies and concentrations of exposure between the two groups and/or potential unmeasured confounding.

CONCLUSION

Our findings suggest positive associations between PFAS and telomere length in women workers, with larger effects seen among firefighters as compared to office workers. The OPFR metabolites BDCPP and BCEP are also associated with telomere length in firefighters and office workers. Associations between chemical exposures and telomere length reported here and by others suggest mechanisms by which these chemicals may affect carcinogenesis and other adverse health outcomes.

Off-Gassing of Semi-Volatile Organic Compounds from Fire-Fighters' Uniforms in Private Vehicles-A Pilot Study

Firefighters' uniforms become contaminated with a wide range of chemicals, including polycyclic aromatic hydrocarbons (PAHs), organophosphate flame retardants (OPFRs), and polybrominated diphenyl ethers (PBDEs). Laundering practices do not completely remove PAHs, OPFRs, and PBDEs from firefighting uniforms. This residual contamination of firefighting ensembles may be an ongoing source of exposure to firefighters. Firefighters are known to occasionally store firefighting ensembles in private vehicles. This study aimed to assess whether a firefighting uniform in a vehicle could act as a source for PAHs, OPFRs, and PBDEs to vehicle users. The shell layers of four laundered firefighting uniforms were sampled non-destructively. Three of these uniforms were heated in a laboratory oven (40, 60, and 80 °C) while the fourth was placed in a private vehicle on a summer day and off-gassing samples were collected from the uniforms. The off-gassing results for PAHs and OPFRs were relatively consistent between laboratory oven and the in-vehicle sample with ∑₁₃ PAHs in off-gas ranging from 7800-23,000 ng uniform^-1 day^-1, while the ∑₆ OPFRs off-gassed was an order of magnitude lower at 620-1600 ng uniform^-1 day^-1. The off-gassing results for PBDEs were much lower and less consistent between the experiments, which may reflect differences in uniform history. Currently, there is limited understanding of how PAHs, OPFRs, and PBDEs off-gassed from firefighting uniforms influence firefighter exposure to these chemicals. These findings suggest that firefighting ensembles off-gassing in private vehicles could be a relevant source of PAHs, OPFRs, and PBDEs that contributes to firefighters' exposure and that this warrants further investigation.

Assessing decontamination and laundering processes for the removal of polycyclic aromatic hydrocarbons and flame retardants from firefighting uniforms

Firefighter uniforms protect firefighters from exposure to potentially harmful chemicals including a range of semi-volatile organic compounds (SVOCs). Contaminated uniforms can become a secondary source of firefighters' exposure to these chemicals. There is inconsistency on the removal efficiency of SVOCs during the cleaning, laundering and field decontamination of firefighting uniforms. Therefore, this study aims to assess how effective decontamination and laundering processes are in reducing firefighter uniforms as a vector for transport and exposure to SVOCs. Firefighters who had attended a controlled house fire and simulated container burns had their uniforms sampled pre- and post-laundering. Clean station wear was laundered with contaminated uniforms and after a load of contaminated uniforms to assess inter and intra load contamination. Surface wipes were collected from uniforms across 12 fire stations, after they had returned from a laundering provider. Concentrations of 13 polycyclic aromatic hydrocarbons (PAHs), six organophosphate flame retardants (OPFRs) and seven polybrominated diphenyl ethers (PBDEs) were measured in the collected samples. The concentrations of ∑₁₃ PAHs in firefighters uniforms ranged between 0.063 and 43 μg g^-1, while concentration of ∑₆ OPFRs were between 0.061 and 90 μg g^-1 with ∑₇ PBDEs concentrations being measured between 0.00054 and 0.97 μg g^-1.The highest concentrations of ∑₁₃ PAHs were measured on the outer layers of gloves at an average of 19 μg g^-1, with the highest ∑₆ OPFRs concentrations being measured in the middle layers of gloves at an average of 31 μg g^-1. The highest ∑₇ PBDEs concentrations were measured on the shell layers of turnout jackets at 0.42 μg g^-1. The significant reduction in ∑₁₃ PAHs after laundering or decontamination was only found in 3 of the 16 sampled areas from firefighting uniforms. No significant differences were found in the between pre- and post-laundering concentrations of ∑₆ OPFRs or ∑₇ PBDEs in firefighting uniforms. The current laundering techniques do not appear to effectively remove PAHs, OPFRs and PBDEs at the measured concentrations from firefighters' uniforms. Further research is required to assess if chemical exposure though firefighting uniforms poses a health risk to firefighters and to develop methods for the removal of SVOCs from firefighting uniforms.

Per- and Polyfluoroalkyl Substances in Dust Collected from Residential Homes and Fire Stations in North America

Over the past few years, human exposure to per- and polyfluoroalkyl substances (PFAS) has garnered increased attention. Research has focused on PFAS exposure via drinking water and diet, and fewer studies have focused on exposure in the indoor environment. To support more research on the latter exposure pathway, we conducted a study to evaluate PFAS in indoor dust. Dust samples from 184 homes in North Carolina and 49 fire stations across the United States and Canada were collected and analyzed for a suite of PFAS using liquid and gas chromatography-mass spectrometry. Fluorotelomer alcohols (FTOHs) and di-polyfluoroalkyl phosphoric acid esters (diPAPs) were the most prevalent PFAS in both fire station and house dust samples, with medians of approximately 100 ng/g dust or greater. Notably, perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate, perfluorononanoic acid, and 6:2 diPAP were significantly higher in dust from fire stations than from homes, and 8:2 FTOH was significantly higher in homes than in fire stations. Additionally, when comparing our results to earlier published values, we see that perfluoroalkyl acid levels in residential dust appear to decrease over time, particularly for PFOA and PFOS. These results highlight a need to better understand what factors contribute to PFAS levels in dust and to understand how much dust contributes to overall human PFAS exposure.

Associations between polyfluoroalkyl substance and organophosphate flame retardant exposures and telomere length in a cohort of women firefighters and office workers in San Francisco

BACKGROUND

Environmental chemical exposures can affect telomere length, which in turn has been associated with adverse health outcomes including cancer. Firefighters are occupationally exposed to many hazardous chemicals and have higher rates of certain cancers. As a potential marker of effect, we assessed associations between chemical exposures and telomere length in women firefighters and office workers from San Francisco, CA.

METHODS

We measured serum levels of polyfluoroalkyl substances (PFAS), urinary metabolites of flame retardants, including organophosphate flame retardants (OPFRs), and telomere length in peripheral blood leukocytes in women firefighters and office workers who participated in the 2014-15 Women Workers Biomonitoring Collaborative. Multiple linear regression models were used to assess associations between chemical exposures and telomere length.

RESULTS

Regression results revealed significant positive associations between perfluorooctanoic acid (PFOA) and telomere length and perfluorooctanesulfonic acid (PFOS) and telomere length among the whole cohort. Models stratified by occupation showed stronger and more significant associations among firefighters as compared to office workers. Among firefighters in models adjusted for age, we found positive associations between telomere length and log-transformed PFOA ( β (95%CI) = 0.57(0.12, 1.02)), PFOS (0.44 (0.05, 0.83)), and perfluorodecanoic acid (PFDA) (0.43 (0.02, 0.84)). Modeling PFAS as categories of exposure showed significant associations between perfluorononanoic acid (PFNA) and telomere length among firefighters. Significant associations between OPFR metabolites and telomere length were seen for bis(1,3-dichloro-2-propyl) phosphate (BDCPP) and telomere length among office workers (0.21(0.03, 0.40)) and bis(2-chloroethyl) phosphate (BCEP) and telomere length among firefighters (-0.14(-0.28, -0.01)). For OPFRs, the difference in the direction of effect by occupational group may be due to the disparate detection frequencies and levels of exposure between the two groups and/or potential unmeasured confounding.

CONCLUSION

Our findings suggest positive associations between PFAS and telomere length in women workers, with larger effects seen among firefighters as compared to office workers. The OPFR metabolites BDCPP and BCEP are also associated with telomere length in firefighters and office workers. Associations between chemical exposures and telomere length reported here and by others suggest mechanisms by which these chemicals may affect carcinogenesis and other adverse health outcomes.

Discovery of firefighter chemical exposures using military-style silicone dog tags

Occupational chemical hazards in the fire service are hypothesized to play a role in increased cancer risk, and reliable sampling technologies are necessary for conducting firefighter chemical exposure assessments. This study presents the military-style dog tag as a new configuration of silicone passive sampling device to sample individual firefighters' exposures at one high and one low fire call volume department in the Kansas City, Missouri metropolitan area. The recruited firefighters (n = 56) wore separate dog tags to assess on- and off-duty exposures (n_dogtags = 110), for a total of 30 24 h shifts. Using a 63 PAH method (GC-MS/MS), the tags detected 45 unique PAHs, of which 18 have not been previously reported as firefighting exposures. PAH concentrations were higher for on- compared to off-duty tags (0.25 < Cohen's d ≤ 0.80) and for the high compared to the low fire call volume department (0.25 ≤ d < 0.70). Using a 1530 analyte screening method (GC-MS), di-n-butyl phthalate, diisobutyl phthalate, guaiacol, and DEET were commonly detected analytes. The number of fire attacks a firefighter participated in was more strongly correlated with PAH concentrations than firefighter rank or years in the fire service. This suggested that quantitative data should be employed for firefighter exposure assessments, rather than surrogate measures. Because several detected analytes are listed as possible carcinogens, future firefighter exposure studies should consider evaluating complex mixtures to assess individual health risks.

Polybrominated Diphenyl Ether and Organophosphate Flame Retardants in Canadian Fire Station Dust

Fire fighters are at a high risk for exposure to toxic chemicals during and subsequent to fire suppression activities. In the Canadian Fire Station Dust Study (CFSDS) we measured 19 polybrominated diphenyl ether (PBDE) and six organophosphate flame retardant (OPFR) chemicals in dust collected in 2017-18 by vacuuming the living quarters of 24 Canadian fire stations from four provinces. The predominant flame retardant (FR) was BDE-209, with a median concentration of 7060 ng/g, which was a magnitude higher than medians of the major congeners of the pentaBDE formulation measured at 620 ng/g (Σ₅ BDE-47, 99, 100, 153 and 154). OPFR median concentrations exceeded those of pentaBDE and were on the same order of magnitude as BDE-209, with TCIPP, TDCIPP and TPHP as the dominant OPFRs with median concentrations ranging from 2350 to 4780 ng/g. Fire station age and carpeting were significantly correlated with select OPFRs and PBDEs. Furthermore, fire stations that also vacuumed equipment bays and fire truck interiors had median concentrations that were a magnitude higher (BDE-209: 81,700 ng/g) and two to three-fold higher (TCIPP, TDCIPP and TPHP) than fire stations that excluded those areas. FR concentrations in CFSDS dust were higher but on the same order of magnitude as Canadian residential dust and significantly lower than dust collected from Canadian WEEE dismantling. CFSDS FR concentrations were also significantly lower than those we reported in our 2015 U.S. fire station dust. Our data reflect the downward trend of PBDEs following their phase out and a shift toward OPFRs as replacements.

Flame retardants, dioxins, and furans in air and on firefighters' protective ensembles during controlled residential firefighting

INTRODUCTION

Structure fires that involve modern furnishings may emit brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs), as well as brominated and chlorinated dioxins and furans, into the environment.

OBJECTIVES

The goal of this study was to quantify the airborne and personal protective equipment (PPE) contamination levels of these compounds during controlled residential fires in the U.S., and to evaluate gross-decontamination measures.

METHODS

Bulk-sampling was done to confirm the presence of flame retardants (FRs) in the furnishings used in 12 controlled residential structure fires. Area air samples were collected during the fires and PPE wipe samples were collected from the firefighters' turnout jackets and gloves after firefighting. For each fire, half of the jackets were decontaminated and the other half were not.

RESULTS

Of the BFRs and OPFRs measured in air during the fire period, decabromodiphenyl ether (BDE-209) and triphenyl phosphate (TPP) were the most abundant, with medians of 15.6 and 408 µg/m³, respectively, and were also detected during overhaul. These and several other BFRs and OPFRs were measured on PPE. Some gloves had contaminant levels exceeding 100 ng/cm² and were generally more contaminated than jackets. Air and surface levels of the brominated furans appeared to be higher than the chlorinated dioxins and furans. Routine gross decontamination appeared to reduce many of the BFR contaminants, but results for the OPFRs were mixed.

CONCLUSIONS

Structure fires are likely to result in a variety of FRs, dioxins, and furans into the environment, leading to PPE contamination for those working on the fireground. Firefighters should wear self-contained breathing apparatus during all phases of the response and launder or decontaminate their PPE (including gloves) after fire events.

Elevated occupational exposure to chlorinated phosphate esters at a construction materials manufacturing plant

BACKGROUND

Numerous studies have documented that the general population is widely exposed to organophosphate esters (OPEs), yet studies on the emissions of OPEs in the industrial application processes and their occupational exposure are scarce. The aim of this study was to assess the exposure to OPEs for workers engaged in OPE-retarded construction material manufacturing plant in China.

METHOD

Paired dust samples (12 samples each time) from an OPEs retarded building materials manufacturing plant during the plant uptime and downtime have been analyzed for tris(2-chloroethyl)-phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCPP), and other commonly used OPEs. Moreover, nine OPEs metabolites (mOPEs) in urine samples (n = 42) from fourteen workers who engaged in this plant were also measured. The daily exposure doses to OPEs were estimated from the measured urinary concentrations of corresponding mOPEs.

RESULTS

Thirteen out of fourteen studied OPEs (except for tri-n-propyl phosphate, TnPP) were determined in all dust samples from the manufacturing plant, and TCEP and TCPP were the predominant compounds in dust collected from the plant uptime and downtime. Overall, the occupationally exposed population had significantly higher (p < 0.01) urinary levels of mOPE, especially for bis (2-chloroethyl) phosphate (BCEP), relative to the reference population. Workshop workers who directly involved in the production of OPEs treated products had higher OPEs exposure. Risk assessment revealed that cancer risk (1.5 × 10^-6-8.5 × 10^-4) for all workers was larger than 1 × 10^-6 when levels of mOPEs in urine from workers were used for estimating OPEs exposure, revealing moderate to high potential cancer risk to workers from OPEs exposure.

CONCLUSION

To our knowledge, this is the first study reporting emissions of OPEs in OPE-treated products manufacturing processes and the potential exposure of the occupationally exposed population. OPEs, especially for TCEP and TCPP, present at elevated levels and pose moderate to high potential health risks to the exposed workers, emphasizing the importance of strengthening occupational exposure prevention in similar industries.

The occurrence of PAHs and flame-retardants in air and dust from Australian fire stations

Firefighters are exposed to a wide range of chemicals whilst on duty, including polycyclic aromatic hydrocarbons (PAHs), organophosphate flame-retardants (OPFRs), and polybrominated diphenyl ethers (PBDEs). These groups of chemicals are related to combustion emissions. PAHs are formed during combustion. OPFRs and PBDEs are flame-retardants and are inadvertently released during combustion. Exposure to these chemicals occurs when attending fire scenes, and firefighters can track these chemicals back into fire stations leading to further exposure. The objective of this study was to understand the concentrations of PAHs, OPFRs, and PBDEs in fire stations, to evaluate factors that affect chemical concentration, and to assess how air and dust could contribute to firefighters' relevant exposure risk. Concentrations of 13 PAHs, 9 OPFRs, and 8 PBDEs were quantified in fire station dust (n = 49) and air (n = 15) samples collected between November 2017 and February 2018. The median ∑₁₃PAH concentration was 15 ng m^-3 and 3.1 µg g^-1 in air and dust, respectively, while the median ∑₉ OPFR concentration was 56 ng m^-3 in air and 84 µg g^-1 in dust, and ∑₈ PBDE had a median concentration of 0.78 ng m^-3 in air and 26 µg g^-1 in dust. The estimated daily intakes through dust and air for ∑₁₃ PAHs, ∑₉ OPFRs, and ∑₈ PBDEs in firefighters were 3.6, 17, and 1.6 ng (kg body weight)^-1day^-1, respectively. The worst-case estimated daily intakes were only 2% of the reference dose for individual chemicals. Pearson's correlations with chemical concentration for several PAHs, OPFRs, and PBDEs were found between the number of years since fire stations were last renovated, as well as the storage locations of firefighting ensembles. These results suggest chemicals are brought back to fire stations from fire scenes and that they are accumulating in fire stations. They also suggest soiled firefighting ensembles are a source of these chemicals in fire stations and that their proximity to the rest of the station determines the extent to which they contribute to chemical concentrations in fire stations.

Quantification of 16 urinary biomarkers of exposure to flame retardants, plasticizers, and organophosphate insecticides for biomonitoring studies

Chlorinated alkyl and non-chlorinated aryl organophosphate flame retardants (OPFRs) and some brominated flame retardants (FR) were introduced as replacements for polybrominated diphenyl ethers (PBDEs) after PBDEs phase-out in 2004 and 2013. Organophosphorous (OP) insecticides are mainly used in agricultural settings since the Food Quality Protection Act of 1996 phased-out most residential uses of OP insecticides in the United States. Urinary metabolites of FRs and OPs are known exposure biomarkers to FRs and OP insecticides, respectively. For large population-based studies, concurrent quantification of these metabolites using a small urine volume is desirable, but until now was not possible. We developed an analytical approach to quantify in 0.2 mL urine 10 FRs and six OP insecticide metabolites: diphenyl phosphate, bis(1,3-dichloro-2-propyl) phosphate, bis(1-chloro-2-propyl) phosphate, bis(2-chloroethyl) phosphate, dicresyl phosphates, dibutyl phosphate, dibenzyl phosphate, 2,3,4,5-tetrabromobenzoic acid, 2-((isopropyl)phenyl)phenyl phosphate, 4-((tert-butyl)phenyl)phenyl phosphate, dimethyl phosphate, diethyl phosphate, dimethyl thiophosphate, dimethyl dithiophosphate, diethyl thiophosphate, and diethyl dithiophosphate. The method relies on enzymatic deconjugation, automated off-line solid phase extraction, high-performance liquid chromatography, and isotope dilution tandem mass spectrometry. Detection limits ranged from 0.05 to 0.5 ng mL-1, accuracy from 89 to 118%, and imprecision was <10%. . This method is the first to quantify simultaneously trace levels of 16 biomarkers of FRs and OP insecticides in only four drops of urine. We confirmed the method suitability for use in large epidemiological studies to assess background and occupational exposures to these classes of environmental pollutants by analyzing 303 samples collected from the general population and a group of firefighters. FR metabolite and DAPs concentrations in the general population group were lower than in the firefighters group, and within the ranges reported in the U.S. general population and other non-occupationally exposed populations.

Comparison of rates of direct and indirect migration of phosphorus flame retardants from flame-retardant-treated polyester curtains to indoor dust

In this study, the pathways for migration of phosphorus flame retardants (PFRs), tris(1,3-dichloroisopropyl) phosphate (TDCPP) and tricresyl phosphate (TCsP) which were detected from curtains often, from flame-retardant-treated polyester curtains to indoor dust were investigated. Two possible migration pathways were compared quantitatively: (1) an indirect pathway in which the PFRs in the curtains first evaporate from the curtains and are then adsorbed onto indoor dust and (2) a direct pathway in which the PFRs are directly transferred to dust placed on the curtains. The contribution of the indirect pathway was evaluated by means of emission cell tests, which showed that the area-specific emission rates from curtains treated with PFRs were 0.044 (TDCPP, Curtain 5), 0.17 (TDCPP, Curtain 8), and 0.060 (TCsP, Curtain 12) μg m^-2 h^-1 at 20 °C (averaged during 24 h). The contribution of the direct pathway was evaluated by measurement of the time dependence of PFR concentrations on the indoor dust placed on the curtains. These measurements indicated that PFR concentrations on the dust increased with time and that the direct migration rates of PFRs from curtains treated with PFRs were 4.4 (TDCPP, Curtain 5), 12 (TDCPP, Curtain 8), and 7.0 (TCsP, Curtain 12) μg m^-2 h^-1 at 20 °C (averaged during 24 h), or 71-120 times the indirect migration rate. This result suggests that the direct pathway can be expected to predominate.

Recent biomonitoring reports on phosphate ester flame retardants: a short review

Organophosphate triesters (PEFRs) are used increasingly as flame retardants and plasticizers in a variety of applications, such as building materials, textiles, and electric and electronic equipment. They have been proposed as alternatives to brominated flame retardants. This updated review shows that biomonitoring has gained incrementally greater importance in evaluating human exposure to PEFRs, and it holds the advantage of taking into account the multiple potential sources and various intake pathways of PEFRs. Simultaneous and extensive internal exposure to a broad range of PEFRs have been reported worldwide. Their metabolites, mainly dialkyl or diaryl diesters, have been used as biomarkers of exposure and have been ubiquitously detected in the urine of adults and children in the general population. Concentrations and profiles of PEFR urinary metabolites are seen to be variable and are highly dependent on individual and environmental factors, including age, country regulation of flame retardants, and types and quantities of emissions in microenvironments, as well as analytical procedures. Additional large biomonitoring studies, using a broad range of urinary diesters and hydroxylated metabolites, would be useful to improve the validity of the biomarkers and to refine assessments of human exposure to PEFRs.