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Demographics of study participants (N = 88) grouped by age (A), gender (B), ethnicity (C), or average household income (D). Bold numbers denote the number of participants within each category, and numbers within parentheses denote the percent of total study participants.
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Organophosphate esters (OPEs) are a class of semi-volatile organic compounds (SVOCs) used as flame retardants, plasticizers, and anti-foaming agents. Due to stringent flammability standards in vehicles and the ability of OPEs to migrate out of end-use products, elevated concentrations of OPEs have been found in car dust samples around the world. As...
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... data for all study participants are included within Table S3. A summary of demographic data demonstrates that, for the most part, study participants ( Fig. 1) represented demographics of UCR's entire undergraduate population (Fig. S1). While our study did not recruit participants younger than 18 years old, 89% of participants were between 18 and 21 years old (Fig. 1A) -a characteristic that was similar to the age distribution within UCR's undergraduate population (Fig. S1). On the other ...
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... data for all study participants are included within Table S3. A summary of demographic data demonstrates that, for the most part, study participants ( Fig. 1) represented demographics of UCR's entire undergraduate population (Fig. S1). While our study did not recruit participants younger than 18 years old, 89% of participants were between 18 and 21 years old (Fig. 1A) -a characteristic that was similar to the age distribution within UCR's undergraduate population (Fig. S1). On the other hand, the gender of our study population was skewed towards a higher proportion ...
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... study participants are included within Table S3. A summary of demographic data demonstrates that, for the most part, study participants ( Fig. 1) represented demographics of UCR's entire undergraduate population (Fig. S1). While our study did not recruit participants younger than 18 years old, 89% of participants were between 18 and 21 years old (Fig. 1A) -a characteristic that was similar to the age distribution within UCR's undergraduate population (Fig. S1). On the other hand, the gender of our study population was skewed towards a higher proportion of females compared to males (Fig. 1B) -a characteristic that was not reflective of UCR's undergraduate population (Fig. S1) -since ...
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... most part, study participants ( Fig. 1) represented demographics of UCR's entire undergraduate population (Fig. S1). While our study did not recruit participants younger than 18 years old, 89% of participants were between 18 and 21 years old (Fig. 1A) -a characteristic that was similar to the age distribution within UCR's undergraduate population (Fig. S1). On the other hand, the gender of our study population was skewed towards a higher proportion of females compared to males (Fig. 1B) -a characteristic that was not reflective of UCR's undergraduate population (Fig. S1) -since there were fewer male participants who had an initial interest in our study despite our diverse recruitment ...
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... did not recruit participants younger than 18 years old, 89% of participants were between 18 and 21 years old (Fig. 1A) -a characteristic that was similar to the age distribution within UCR's undergraduate population (Fig. S1). On the other hand, the gender of our study population was skewed towards a higher proportion of females compared to males (Fig. 1B) -a characteristic that was not reflective of UCR's undergraduate population (Fig. S1) -since there were fewer male participants who had an initial interest in our study despite our diverse recruitment methods. Similar to age, the distribution of study participant ethnicity (Fig. 1C) was similar to UCR's undergraduate population (Fig. ...
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... 18 and 21 years old (Fig. 1A) -a characteristic that was similar to the age distribution within UCR's undergraduate population (Fig. S1). On the other hand, the gender of our study population was skewed towards a higher proportion of females compared to males (Fig. 1B) -a characteristic that was not reflective of UCR's undergraduate population (Fig. S1) -since there were fewer male participants who had an initial interest in our study despite our diverse recruitment methods. Similar to age, the distribution of study participant ethnicity (Fig. 1C) was similar to UCR's undergraduate population (Fig. S1), where the top four ethnicities were Hispanic, Asian, White, and Multi-Racial. The ...
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... skewed towards a higher proportion of females compared to males (Fig. 1B) -a characteristic that was not reflective of UCR's undergraduate population (Fig. S1) -since there were fewer male participants who had an initial interest in our study despite our diverse recruitment methods. Similar to age, the distribution of study participant ethnicity (Fig. 1C) was similar to UCR's undergraduate population (Fig. S1), where the top four ethnicities were Hispanic, Asian, White, and Multi-Racial. The "other" ethnicity category within the undergraduate population (Fig. S1) includes ethnicities that, despite various attempts to recruit campus-wide, were not represented within our final study ...
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... to males (Fig. 1B) -a characteristic that was not reflective of UCR's undergraduate population (Fig. S1) -since there were fewer male participants who had an initial interest in our study despite our diverse recruitment methods. Similar to age, the distribution of study participant ethnicity (Fig. 1C) was similar to UCR's undergraduate population (Fig. S1), where the top four ethnicities were Hispanic, Asian, White, and Multi-Racial. The "other" ethnicity category within the undergraduate population (Fig. S1) includes ethnicities that, despite various attempts to recruit campus-wide, were not represented within our final study population (Black or African American; Native Hawaiian or ...
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... initial interest in our study despite our diverse recruitment methods. Similar to age, the distribution of study participant ethnicity (Fig. 1C) was similar to UCR's undergraduate population (Fig. S1), where the top four ethnicities were Hispanic, Asian, White, and Multi-Racial. The "other" ethnicity category within the undergraduate population (Fig. S1) includes ethnicities that, despite various attempts to recruit campus-wide, were not represented within our final study population (Black or African American; Native Hawaiian or Pacific Islander; or Unknown). Finally, the average household income -either reported as parental or personal income from dependent or independent students, ...
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... American; Native Hawaiian or Pacific Islander; or Unknown). Finally, the average household income -either reported as parental or personal income from dependent or independent students, respectively -for our study population contained a higher proportion of students within the average household income of < $30,000 and $75,001-$110,000 groups (Fig. 1D), a characteristic that was not similar to UCR's undergraduate population (Fig. ...
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... household income -either reported as parental or personal income from dependent or independent students, respectively -for our study population contained a higher proportion of students within the average household income of < $30,000 and $75,001-$110,000 groups (Fig. 1D), a characteristic that was not similar to UCR's undergraduate population (Fig. ...
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... Previous research has suggested that commuting may contribute to FR exposure. Reddam et al. 26 assessed the chemical exposures of commuters in Southern California using silicone wristbands and found that exposure to TDCIPP was correlated with the amount of time spent using vehicular transportation (personal vehicle, public transport, rideshare, etc.). TDCIPP has also been identified in vehicle dust at higher concentrations than other indoor microenvironments, such as bedrooms 27 and offices. ...
... Our data suggest that this listing has resulted in a substitution of TCIPP in place of TDCIPP, which would explain the high detections of TCIPP in vehicles as well as lower TDCIPP detections compared to previous vehicle studies. 26,27,52 This substitution is concerning given the higher vapor pressure of TCIPP (1.35 × 10 −3 mmHg) 53 compared to TDCIPP (7.22 × 10 −6 mmHg), 54 making TCIPP more likely to be released from foams and other sources into vehicle cabin air. Growing evidence on the negative health effects of TCIPP, and the increased potential for airborne exposure to this compound, suggests yet another case of regrettable substitution. ...
Flame retardants (FRs) are added to vehicles to meet flammability standards, such as US Federal Motor Vehicle Safety Standard FMVSS 302. However, an understanding of which FRs are being used, sources in the vehicle, and implications for human exposure is lacking. US participants (n = 101) owning a vehicle of model year 2015 or newer hung a silicone passive sampler on their rearview mirror for 7 days. Fifty-one of 101 participants collected a foam sample from a vehicle seat. Organophosphate esters (OPEs) were the most frequently detected FR class in the passive samplers. Among these, tris(1-chloro-isopropyl) phosphate (TCIPP) had a 99% detection frequency and was measured at levels ranging from 0.2 to 11,600 ng/g of sampler. TCIPP was also the dominant FR detected in the vehicle seat foam. Sampler FR concentrations were significantly correlated with average ambient temperature and were 2–5 times higher in the summer compared to winter. The presence of TCIPP in foam resulted in ∼4 times higher median air sampler concentrations in winter and ∼9 times higher in summer. These results suggest that FRs used in vehicle interiors, such as in seat foam, are a source of OPE exposure, which is increased in warmer temperatures.
... People can be exposed to triphenyl phosphate in a variety of ways; this chemical is used as a plasticizer, a lubricant, and a component of commonly used commercial flame retardant formulations (Phillips et al., 2017;van der Veen and de Boer, 2012). Recent research indicates that flame retardants are found in vehicles and time spent traveling in a vehicle can lead to increased personal exposure to some flame retardants in certain cases (Reddam et al., 2020). Specifically, wristbands were worn during commutes and authors found that triphenyl phosphate was strongly correlated with other flame retardants and that longer commutes were associated with increased exposure to one flame retardant, tris(1,3-dichloro-2-propyl)phosphate (Reddam et al., 2020). ...
... Recent research indicates that flame retardants are found in vehicles and time spent traveling in a vehicle can lead to increased personal exposure to some flame retardants in certain cases (Reddam et al., 2020). Specifically, wristbands were worn during commutes and authors found that triphenyl phosphate was strongly correlated with other flame retardants and that longer commutes were associated with increased exposure to one flame retardant, tris(1,3-dichloro-2-propyl)phosphate (Reddam et al., 2020). More research is needed to better understand how vehicle conditions, such as vehicle age, air temperature, and time spent in a vehicle, influences personal chemical exposure. ...
To understand how chemical exposure can impact health, researchers need tools that capture the complexities of personal chemical exposure. In practice, fine particulate matter (PM2.5) air quality index (AQI) data from outdoor stationary monitors and Hazard Mapping System (HMS) smoke density data from satellites are often used as proxies for personal chemical exposure, but do not capture total chemical exposure. Silicone wristbands can quantify more individualized exposure data than stationary air monitors or smoke satellites. However, it is not understood how these proxy measurements compare to chemical data measured from wristbands. In this study, participants wore daily wristbands, carried a phone that recorded locations, and answered daily questionnaires for a 7‐day period in multiple seasons. We gathered publicly available daily PM2.5 AQI data and HMS data. We analyzed wristbands for 94 organic chemicals, including 53 polycyclic aromatic hydrocarbons. Wristband chemical detections and concentrations, behavioral variables (e.g., time spent indoors), and environmental conditions (e.g., PM2.5 AQI) significantly differed between seasons. Machine learning models were fit to predict personal chemical exposure using PM2.5 AQI only, HMS only, and a multivariate feature set including PM2.5 AQI, HMS, and other environmental and behavioral information. On average, the multivariate models increased predictive accuracy by approximately 70% compared to either the AQI model or the HMS model for all chemicals modeled. This study provides evidence that PM2.5 AQI data alone or HMS data alone is insufficient to explain personal chemical exposures. Our results identify additional key predictors of personal chemical exposure.
... Log transformation is a common technique to stabilize variances and transform skewed data distributions to approximately normal distributions and is commonly used in wristband study analyses (e.g. [13,25]). On a log-transformed scale, chemical concentrations above LOD can be reasonably approximated by a normal distribution ( Fig. 3B-D). ...
Wearable silicone wristbands are a rapidly growing exposure assessment technology that offer researchers the ability to study previously inaccessible cohorts and have the potential to provide a more comprehensive picture of chemical exposure within diverse communities. However, there are no established best practices for analyzing the data within a study or across multiple studies, thereby limiting impact and access of these data for larger meta-analyses. We utilize data from three studies, from over 600 wristbands worn by participants in New York City and Eugene, Oregon, to present a first-of-its-kind manuscript detailing wristband data properties. We further discuss and provide concrete examples of key areas and considerations in common statistical modeling methods where best practices must be established to enable meta-analyses and integration of data from multiple studies. Finally, we detail important and challenging aspects of machine learning, meta-analysis, and data integration that researchers will face in order to extend beyond the limited scope of individual studies focused on specific populations.
... ; https://doi.org/10.1101/2023.09.29.560217 doi: bioRxiv preprint transformation is a common technique to stabilize variances and transform skewed data distributions to approximately normal distributions and is commonly used in wristband study analyses (e.g. [13,25]). On a log-transformed scale, chemical concentrations above LOD can be reasonably approximated by a normal distribution (Fig. 3B-D). ...
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... TDCIPP, the parent compound of BDCIPP, is known to be present in car upholstery, where elevated temperatures can lead to an increase in volatilization (Phillips et al., 2018). There is evidence from the USA that longer commutes lead to increased TDCIPP exposure (Reddam et al., 2020). ...
Many legacy and emerging flame retardants (FRs) have adverse human and environmental health effects. This study reports legacy and emerging FRs in children from nine European countries from the HBM4EU aligned studies. Studies from Belgium, Czech Republic, Germany, Denmark, France, Greece, Slovenia, Slovakia, and Norway conducted between 2014 and 2021 provided data on FRs in blood and urine from 2136 children. All samples were collected and analyzed in alignment with the HBM4EU protocols. Ten halogenated FRs were quantified in blood, and four organophosphate flame retardants (OPFR) metabolites quantified in urine. Hexabromocyclododecane (HBCDD) and decabromodiphenyl ethane (DBDPE) were infrequently detected (<16% of samples). BDE-47 was quantified in blood from Greece, France, and Norway, with France (0.36 ng/g lipid) having the highest concentrations. BDE-153 and -209 were detected in <40% of samples. Dechlorane Plus (DP) was quantified in blood from four countries, with notably high median concentrations of 16 ng/g lipid in Slovenian children. OPFR metabolites had a higher detection frequency than other halogenated FRs. Diphenyl phosphate (DPHP) was quantified in 99% of samples across 8 countries at levels ∼5 times higher than other OPFR metabolites (highest median in Slovenia of 2.43 ng/g lipid). FR concentrations were associated with lifestyle factors such as cleaning frequency, employment status of the father of the household, and renovation status of the house, among others. The concentrations of BDE-47 in children from this study were similar to or lower than FRs found in adult matrices in previous studies, suggesting lower recent exposure and effectiveness of PBDE restrictions.
... Our protocols for the preparation and analysis of the wristband samples followed previous publications (Hammel et al., 2016(Hammel et al., , 2018Reddam et al., 2020;Wise et al., 2020). Before sending sample kits to participants, we cleaned the red silicone wristbands using solvent extraction and wrapped the wristbands in pre-cleaned aluminum foil and Ziploc bags. ...
Humans are exposed to increasingly complex mixtures of hormone-disrupting chemicals from a variety of sources, yet, traditional research methods only evaluate a small number of chemicals at a time. We aimed to advance novel methods to investigate exposures to complex chemical mixtures. Silicone wristbands were worn by 243 office workers in the USA, UK, China, and India during four work shifts. We analyzed extracts of the wristbands for: 1) 99 known (targeted) chemicals; 2) 1000+ unknown chemical features, tentatively identified through suspect screening; and 3) total hormonal activities towards estrogen (ER), androgen (AR), and thyroid hormone (TR) receptors in human cell assays. We evaluated associations of chemicals with hormonal activities using Bayesian kernel machine regression models, separately for targeted versus suspect chemicals (with detection ≥50%). Every wristband exhibited hormonal activity towards at least one receptor: 99% antagonized TR, 96% antagonized AR, and 58% agonized ER. Compared to men, women were exposed to mixtures that were more estrogenic (180% higher, adjusted for country, age, and skin oil abundance in wristband), anti-androgenic (110% higher), and complex (median 836 detected chemical features versus 780). Adjusted models showed strong associations of jointly increasing chemical concentrations with higher hormonal activities. Several targeted and suspect chemicals were important co-drivers of overall mixture effects, including chemicals used as plasticizers, fragrance, sunscreen, pesticides, and from other or unknown sources. This study highlights the role of personal care products and building microenvironments in hormone-disrupting exposures, and the substantial contribution of chemicals not often identifiable or well-understood to those exposures.
... Numerous studies in the US have used these wearable tools to characterise personal exposures of organophosphate ester flame retardants (OPFRs) (Hammel et al., 2016;Reddam et al., 2020), polycyclic aromatic hydrocarbons (PAHs) (Dixon et al., 2018;Hendryx et al., 2020;Paulik et al., 2018;Rohlman et al., 2019a;Rohlman et al., 2019b), polybrominated diphenyl ethers (PBDEs) (Hammel et al., 2018), pesticides (Aerts et al., 2018), and a variety of pollutants Bergmann et al., 2018;Craig et al., 2019;Donald et al., 2019;Nicole, 2018;Romanak et al., 2019;Wang et al., 2019;Shaorui Wang et al., 2020;Zuy et al., 2020). Other studies in the US have examined children's exposures to PBDEs (Kile et al., 2016;Lipscomb et al., 2017), OPFRs (Gibson et al., 2019;Hammel et al., 2020;Kile et al., 2016;Lipscomb et al., 2017), phthalates , PAHs (Lin et al., 2020), pesticides (Harley et al., 2019;Vidi et al., 2017), and nicotine (Quintana et al., 2019). ...
The burden of disease associated with environmental exposures disproportionately impacts low- and middle-income countries. Children living in rural regions of these countries may experience higher exposure to insecticides from indoor residual spraying used for malaria control and household air pollution. This study evaluated environmental exposures of children living in rural regions of South Africa. Quantifying exposure levels and identifying characteristics that are associated with exposure in this geographic region has been challenging due to limitations with available monitoring techniques. Wearable passive samplers have recently been shown to be a convenient and reliable tool for assessing personal exposures. In this study, a passive sampler wristband, known as Fresh Air wristband, was worn by 49 children (five-years of age) residing in the Limpopo province of South Africa. The study leveraged ongoing research within the Venda Health Examination of Mothers, Babies, and their Environment (VHEMBE) birth cohort. A wide range of chemicals (35 in total) were detected using the wristbands, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides, phthalates, and organophosphate esters (OPEs) flame retardants. Higher concentrations of PAHs were observed among children from households that fell below the food poverty threshold, did not have access to electric cookstoves/burners, or reported longer times of cooking or burning materials during the sampling period. Concentrations of p,p’-DDD and p,p’-DDT were also found to be elevated for children from households falling below the food poverty threshold as well as for children whose households were sprayed for malaria control within the previous 1.5 years. This study demonstrates the feasibility of using passive sampler wristbands as a non-invasive method for personal exposure assessment of children in rural regions of South Africa to complex mixtures environmental contaminants derived from a combination of sources. Future studies are needed to further identify and understand the effects of airborne environmental contaminants on childhood development and strategies to mitigate exposures.
... As an SVOC, TDCIPP migrates from end-use products (e.g., polyurethane foam) into the air and partitions into environmental media such as indoor dust. For example, longer commutes are associated with increased human exposure to TDCIPP (Brandsma et al., 2014;Reddam et al., 2020), a finding that may be due to migration of TDCIPP from interior parts of vehicles such as car seats. In a cross-sectional European human biomonitoring study, TDCIPP and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP, the primary metabolite of TDCIPP) were detected within 93% of hair follicle samples from mother-child pairs (Kucharska et al., 2015), suggesting that human exposure to TDCIPP is ubiquitous. ...
Tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) is an organophosphate ester-based flame retardant widely used within the United States. Within zebrafish, initiation of TDCIPP exposure at 0.75 h post-fertilization (hpf) reliably disrupts cytosine methylation from cleavage (2 hpf) through early-gastrulation (6 hpf). Therefore, the objective of this study was to determine whether TDCIPP-induced effects on cytosine methylation persist beyond 6 hpf. First, we exposed embryos to vehicle or TDCIPP from 0.75 hpf to 6, 24, or 48 hpf, and then conducted bisulfite amplicon sequencing of a target locus (lmo7b) using genomic DNA derived from whole embryos. Within both vehicle- and TDCIPP-treated embryos, CpG methylation was similar at 6 hpf and CHG/CHH methylation were similar at 24 and 48 hpf (relative to 6 hpf). However, relative to 6 hpf within the same treatment, CpG methylation was lower within vehicle-treated embryos at 48 hpf and TDCIPP-treated embryos at 24 and 48 hpf – an effect that was driven by acceleration of CpG hypomethylation. Similar to our previous findings with DNA methyltransferase, we found that, even at high μM concentrations, TDCIPP had no effect on zebrafish and human thymine DNA glycosylase activity (a key enzyme that decreases CpG methylation), suggesting that TDCIPP-induced effects on CpG methylation are not driven by direct interaction with thymine DNA glycosylase. Finally, using 5-methylcytosine (5-mC)-specific whole-mount immunochemistry and automated imaging, we found that exposure to TDCIPP increased 5-mC abundance within the yolk of blastula-stage embryos, suggesting that TDCIPP may impact cytosine methylation of maternally loaded mRNAs during the maternal-to-zygotic transition. Overall, our findings suggest that TDCIPP disrupts the trajectory of cytosine methylation during zebrafish embryogenesis, effects which do not appear to be driven by direct interaction of TDCIPP with key enzymes that regulate cytosine methylation.
... Study participants can wear these samplers as a wristband, lapel, dog tag, or other configuration (Dixon et al. 2020;O'Connell et al., 2014;Poutasse et al. 2020). Since silicone wearables were first reported on in 2014, they have been used in over 30 exposure assessment studies and have been worn by thousands of people on six continents (Bullock et al. 2020;Craig et al. 2019;De Vecchi et al. 2019;Dixon et al. 2020;Hammel et al. 2020;Hendryx et al. 2020;Reche et al. 2020;Reddam et al. 2020;Rohlman et al. 2019;Wang et al., 2020;Wang et al., 2019;Wise et al. 2020;Zuy et al. 2020). Silicone wearables are passive sampling devices, which sequester the fraction of chemicals that are available to transport across cellular membranes (Anderson and Hillwalker 2008;O'Connell et al., 2014). ...
During events like the COVID-19 pandemic or a disaster, researchers may need to switch from collecting biological samples to personal exposure samplers that are easy and safe to transport and wear, such as silicone wristbands. Previous studies have demonstrated significant correlations between urine biomarker concentrations and chemical levels in wristbands. We build upon those studies and use a novel combination of descriptive statistics and supervised statistical learning to evaluate the relationship between polycyclic aromatic hydrocarbon (PAH) concentrations in silicone wristbands and hydroxy-PAH (OH-PAH) concentrations in urine. In New York City, 109 participants in a longitudinal birth cohort wore one wristband for 48 h and provided a spot urine sample at the end of the 48-hour period during their third trimester of pregnancy. We compared four PAHs with the corresponding seven OH-PAHs using descriptive statistics, a linear regression model, and a linear discriminant analysis model. Five of the seven PAH and OH-PAH pairs had significant correlations (Pearson’s r = 0.35–0.64, p ≤ 0.003) and significant chi-square tests of independence for exposure categories (p ≤ 0.009). For these five comparisons, the observed PAH or OH-PAH concentration could predict the other concentration within a factor of 1.47 for 50–80% of the measurements (depending on the pair). Prediction accuracies for high exposure categories were at least 1.5 times higher compared to accuracies based on random chance. These results demonstrate that wristbands and urine provide similar PAH exposure assessment information, which is critical for environmental health researchers looking for the flexibility to switch between biological sample and wristband collection.
... Wristband extraction for SVOCs is described in detail elsewhere, [22][23][24] but briefly, the mass of a small piece (~0.75 g) piece of each wristband was first recorded and then cut into three pieces and transferred to a glass centrifuge tube for extraction. Samples were spiked with isotopically labeled internal standards and extracted using 1:1 hexane:dichloromethane (Supplemental Information (SI) Table S1). ...
Firefighters are occupationally exposed to an array of hazardous chemicals, and these exposures have been linked to the higher rates of some cancer in firefighters. However, additional research that characterizes firefighters' exposure is needed to fully elucidate the impacts on health risks. In a pilot study, we used silicone wristbands to quantify off-duty and on-duty chemical exposures experienced by 20 firefighters in Durham, North Carolina. By using each firefighter's off-duty wristband to represent individual baseline exposures, we assessed occupation-related exposures (i.e. on-duty exposures). We also investigated the influence of responding to a fire event while on-duty. In total, 134 chemicals were quantified using both GC–MS/MS and LC-MS/MS targeted methods. Seventy-one chemicals were detected in at least 50% of all silicone wristbands, including 7 PFAS, which to our knowledge, have not been reported on wristbands previously. Of these, phthalates were generally measured at the highest concentrations, followed by brominated flame retardants (BFRs) and organophosphate esters (OPEs). PFAS were measured at lower concentrations overall, but firefighter PFOS exposures while on-duty and responding to fires were 2.5 times higher than off-duty exposures. Exposure to polycyclic aromatic hydrocarbons (PAH), BFRs, and some OPEs were occupationally associated, with firefighters experiencing 0.5 to 8.5 times higher exposure while on-duty as compared to off-duty. PAH exposures were also higher for firefighters who respond to a fire than those who did not while on-duty. Additional research with a larger population of firefighters that builds upon this pilot investigation may further pinpoint exposure sources that may contribute to firefighters' risk for cancer, such as those from firefighter gear or directly from fires. This research demonstrates the utility of using silicone wristbands to quantify occupational exposure in firefighters and the ability to disentangle exposures that may be specific to fire events as opposed to other sources that firefighters might experience.
