PM2.5 Is Insufficient to Explain Personal PAH 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.

Predicting personal PAH exposure using high dimensional questionnaire and wristband data.

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are a class of pervasive environmental pollutants with a variety of known health effects. While significant work has been completed to estimate personal exposure to PAHs, less has been done to identify sources of these exposures. Comprehensive characterization of reported sources of personal PAH exposure is a critical step to more easily identify individuals at risk of high levels of exposure and for developing targeted interventions based on source of exposure. OBJECTIVE: In this study, we leverage data from a New York (NY)-based birth cohort to identify personal characteristics or behaviors associated with personal PAH exposure and develop models for the prediction of PAH exposure. METHODS: We quantified 61 PAHs measured using silicone wristband samplers in association with 75 questionnaire variables from 177 pregnant individuals. We evaluated univariate associations between each compound and questionnaire variable, conducted regression tree analysis for each PAH compound and completed a principal component analysis of for each participant's entire PAH exposure profile to determine the predictors of PAH levels. RESULTS: Regression tree analyses of individual compounds and exposure mixture identified income, time spent outdoors, maternal age, country of birth, transportation type, and season as the variables most frequently predictive of exposure.

Concurrent assessment of diffusive and advective PAH movement strongly affected by temporal and spatial changes.

Chemical movement influences exposure, remediation and interventions. Understanding chemical movement in addition to chemical concentrations at contaminated sites is critical to informed decision making. Using seepage meters and passive sampling devices we assessed both diffusive and advective flux of bioavailable polycyclic aromatic hydrocarbons (PAHs) at three time points, across two seasons, at a former creosote site in St. Helens, Oregon, United States. To our knowledge, this is the first time both diffusive and advective fluxes have been measured simultaneously at a contaminated site. Concentrations of 39 parent PAHs were determined by gas chromatography triple quadrupole mass spectrometry. Across both seasons and all sites, diffusive flux of PAHs was up to three orders of magnitude larger than advective flux. Release of PAHs from sediments and water were identified, likely from legacy contamination, as well as deposition from the air into the site from contemporary and other sources. The majority of PAH movement was comprised of three and four ring PAHs. Chemical movement on the site was found to be spatially and temporally variable. Volatilization decreased and atmospheric deposition increased from summer to fall. At the locations with higher levels of contamination, sum PAH release from sediments decreased by more than two orders of magnitude from summer to late fall. These data reflect the spatial heterogeneity and temporal variability of this site and demonstrate the importance of seasonality in assessing chemical movement at contaminated sites. Results from this study can inform future legacy site assessments to optimize remediation strategies and assess remediation effectiveness.

Neuroanatomical differences in Latinx children from rural farmworker families and urban non-farmworker families and related associations with pesticide exposure.

Exposure to pesticides in humans may lead to changes in brain structure and function and increase the likelihood of experiencing neurodevelopmental disorders. Despite the potential risks, there is limited neuroimaging research on the effects of pesticide exposure on children, particularly during the critical period of brain development. Here we used voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) from magnetic resonance images (MRI) to investigate neuroanatomical differences between Latinx children (n = 71) from rural, farmworker families (FW; n = 48) and urban, non-farmworker families (NFW; n = 23). Data presented here serves as a baseline for our ongoing study examining the longitudinal effects of living in a rural environment on neurodevelopment and cognition in children. The VBM analysis revealed that NFW children had higher volume in several distinct regions of white matter compared to FW children. Tract-based spatial statistics (TBSS) of DTI data also indicated NFW children had higher fractional anisotropy (FA) in several key white matter tracts. Although the difference was not as pronounced as white matter, the VBM analysis also found higher gray matter volume in selected regions of the frontal lobe in NFW children. Notably, white matter and gray matter findings demonstrated a high degree of overlap in the medial frontal lobe, a brain region predominantly linked to decision-making, error processing, and attention functions. To gain further insights into the underlying causes of the observed differences in brain structure between the two groups, we examined the association of organochlorine (OC) and organophosphate (OP) exposure collected from passive dosimeter wristbands with brain structure. Based on our previous findings within this data set, demonstrating higher OC exposure in children from non-farmworker families, we hypothesized OC might play a critical role in structural differences between NFW and FW children. We discovered a significant positive correlation between the number of types of OC exposure and the structure of white matter. The regions with significant association with OC exposure were in agreement with the findings from the FW-NFW groups comparison analysis. In contrast, OPs did not have a statistically significant association with brain structure. This study is among the first multimodal neuroimaging studies examining the brain structure of children exposed to agricultural pesticides, specifically OC. These findings suggest OC pesticide exposure may disrupt normal brain development in children, highlighting the need for further neuroimaging studies within this vulnerable population.

Pesticide Exposure among Latinx Children in Rural Farmworker and Urban Non-Farmworker Communities: Associations with Locality and Season.

This study uses repeated measures to document the pesticide exposure of rural and urban Latinx children (age eight at baseline), and to compare these children in terms of the frequency and concentration of their exposure to a large set of pesticides, accounting for season. We used silicone wristbands worn for one week up to ten times at quarterly intervals from 2018 to 2022 to assess pesticide exposure in children from rural farmworker (n = 75) and urban non-farmworker (n = 61) families. We determined the detection and concentrations (ng/g) of 72 pesticides and pesticide degradation products in the wristbands using gas chromatography electron capture detection and gas chromatography mass spectrometry. The most frequently detected pesticide classes were organochlorines, pyrethroids, and organophosphates. Controlling for season, organochlorine or phenylpyrazole detections were less likely for rural children than for urban children. Detections of organochlorines, pyrethroids, or organophosphates were lower in spring and summer versus winter. Controlling for season, urban children had greater concentrations of organochlorines, while rural children had greater concentrations of pyrethroids and Chlorpyrifos. Pesticide concentrations were lower in winter and spring compared with summer and fall. These results further document that pesticides are ubiquitous in the living environment for children in vulnerable, immigrant communities.

Silicone passive sampling used to identify novel dermal chemical exposures of firefighters and assess PPE innovations.

A plethora of chemicals are released into the air during combustion events, including a class of compounds called polycyclic aromatic hydrocarbons (PAHs). PAHs have been implicated in increased risk of cancer and cardiovascular disease, both of which are disease endpoints of concern in structural firefighters. Current commercially available personal protective equipment (PPE) typically worn by structural firefighters during fire responses have gaps in interfaces between the ensemble elements (e.g., hood and jacket) that allow for ingress of contaminants and dermal exposure. This pilot study aims to use silicone passive sampling to assess improvements in dermal protection afforded by a novel configuration of PPE, which incorporates a one-piece liner to eliminate gaps in two critical interfaces between pieces of gear. The study compared protection against parent and alkylated PAHs between the one-piece liner PPE and the standard configuration of PPE with traditional firefighting jacket and pants. Mannequins (n = 16) dressed in the PPE ensembles were placed in a Fireground Exposure Simulator for 10 min, and exposed to smoke from a combusting couch. Silicone passive samplers were placed underneath PPE at vulnerable locations near interfaces in standard PPE, and in the chamber air, to measure PAHs and calculate the dermal protection provided by both types of PPE. Silicone passive sampling methodology and analyses using gas chromatography with mass-spectrometry proved to be well-suited for this intervention study, allowing for the calculation and comparison of worker protection factors for 51 detected PAHs. Paired comparisons of the two PPE configurations found greater sum 2-3 ring PAH exposure underneath the standard PPE than the intervention PPE at the neck and chest, and at the chest for 4-7 ring PAHs (respective p-values: 0.00113, 0.0145, and 0.0196). Mean worker protection factors of the intervention PPE were also greater than the standard PPE for 98% of PAHs at the neck and chest. Notably, the intervention PPE showed more than 30 times the protection compared to the standard PPE against two highly carcinogenic PAHs, dibenzo[a,l]pyrene and benzo[c]fluorene. Nine of the detected PAHs in this study have not been previously reported in fireground exposure studies, and 26 other chemicals (not PAHs) were detected using a large chemical screening method on a subset of the silicone samplers. Silicone passive sampling appears to be an effective means for measuring dermal exposure reduction to fireground smoke, providing evidence in this study that reducing gaps in PPE interfaces could be further pursued as an intervention to reduce dermal exposure to PAHs, among other chemicals.

Wildfire Impact on Indoor and Outdoor PAH Air Quality.

Air quality impacts from wildfires are poorly understood, particularly indoors. As frequencies increase, it is important to optimize methodologies to understand and reduce chemical exposures from wildfires. Public health recommendations use air quality estimates from outdoor stationary air monitors, discounting indoor air conditions, and do not consider chemicals in the vapor phase, known to elicit adverse effects. We investigated vapor-phase polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor air before, during, and after wildfires using a community-engaged research approach. Paired passive air samplers were deployed at 15 locations across four states. Twelve unique PAHs were detected only in outdoor air during wildfires, highlighting a PAH exposure mixture for future study. Heavy-molecular-weight (HMW) outdoor PAH concentrations and average Air Quality Index (AQI) values were positively correlated (p < 0.001). Indoor PAH concentrations were higher in 77% of samples across all sampling events. Even during wildfires, 58% of sampled locations still had higher indoor PAH air concentrations. When AQI values exceeded 140 (unhealthy for sensitive groups), outdoor PAH concentrations became similar to or higher than indoors. Cancer and noncancer inhalation risk estimates from vapor-phase PAHs were higher indoors than outdoors, regardless of the wildfire impact. Consideration of indoor air quality and vapor-phase PAHs could inform public health recommendations regarding wildfires.

Evaluating predictive relationships between wristbands and urine for assessment of personal PAH exposure.

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.

Preschool-Age Children's Pesticide Exposures in Child Care Centers and at Home in Northern California.

INTRODUCTION: Young children may be exposed to pesticides used in child care centers and their family homes. We examined pesticide use and environmental and behavioral factors potentially associated with child exposures in these settings. METHOD: Preschool-age children (n = 125) wore silicone wristbands to assess pesticide exposures in their child care centers and home environments. Information about environmental and behavioral exposure determinants was collected using parent surveys, child care director interviews, and observations. RESULTS: Commonly detected pesticides were bifenthrin, chlorpyrifos, cypermethrin, fipronil, and cis- and trans-permethrin. Pesticide chemical storage onsite, cracks in the walls, using doormats, observed pests, or evidence of pests were associated with child exposures. Exposures were higher in counties with higher agricultural or commercial pesticide use or when children lived in homes near agricultural fields. DISCUSSION: Young children are being exposed to harmful pesticides, and interventions are needed to lower their risk of health problems later in life.

Pesticide exposure among Latinx child farmworkers in North Carolina.

BACKGROUND: Although pesticides have adverse effects on child health and development, little research has examined pesticide exposure among child farmworkers. This analysis addresses two specific aims: (1) describes pesticide exposure among Latinx child farmworkers in North Carolina, and (2) delineates factors associated with this pesticide exposure. METHODS: In 2018 (n = 173) and 2019 (n = 156) Latinx child farmworkers completed interviews and wore silicone wristbands for a single day to measure pesticide exposure. Wristbands were analyzed for 70 pesticides. RESULTS: Most Latinx child farmworkers were exposed to multiple pesticides; the most frequent were pyrethroids (69.9% in 2018, 67.9% in 2019), organochlorines (51.4% in 2018, 55.1% in 2019), and organophosphates (51.4% in 2018, 34.0% in 2019). Children were exposed to a mean of 2.15 pesticide classes in 2018 and 1.91 in 2019, and to a mean of 4.06 pesticides in 2018 and 3.34 in 2019. Younger children (≤15 years) had more detections than older children; children not currently engaged in farm work had more detections than children currently engaged in farm work. Migrant child farmworkers had more detections than nonmigrants. For specific pesticides with at least 20 detections, detections and concentrations were generally greater among children not currently engaged in farm work than children currently engaged. CONCLUSIONS: Children who live in farmworker communities are exposed to a plethora of pesticides. Although further research is needed to document the extent of pesticide exposure and its health consequences, sufficient information is available to inform the policy needed to eliminate this pesticide exposure in agricultural communities.

Pesticide exposure among Latinx children: Comparison of children in rural, farmworker and urban, non-farmworker communities.

Personal pesticide exposure is not well characterized among children in vulnerable, immigrant communities. We used silicone wristbands in 2018-2019 to assess pesticide exposure in 8 year old Latinx boys and girls in rural, farmworker families (n = 73) and urban, non-farmworker families (n = 60) living in North Carolina who were enrolled in the PACE5 Study, a community-based participatory research study. We determined the detection and concentrations (ng/g) of 75 pesticides and pesticide degradation products in the silicone wristbands worn for one week using gas chromatography electron capture detection and employed gas chromatography mass spectrometry. Differences by personal and family characteristics were tested using analysis of variance or Wilcoxon Rank Sum tests when necessary. Pesticide concentrations above the limit of detection were analyzed, and reported as geometric means and 95% confidence intervals (CI). The most frequently detected pesticide classes were organochlorines (85.7%), pyrethroids (65.4%), and organophosphates (59.4%), with the most frequently detected specific pesticides being alpha-chlordane (69.2%), trans-nonachlor (67.7%), gamma-chlordane (66.2%), chlorpyrifos (54.9%), cypermethrin (49.6%), and trans-permethrin (39.1%). More of those children in urban, non-farmworker families had detections of organochlorines (93.3% vs. 79.5, p = 0.0228) and pyrethroids (75.0% vs. 57.5%, p = 0.0351) than did those in rural, farmworker families; more children in rural, farmworker families had detections for organophosphates (71.2% vs. 45.0%, p= 0.0022). Children in urban, non-farmworker families had greater concentrations of alpha-chlordane (geometric mean (GM) 18.98, 95% CI 14.14, 25.47 vs. 10.25, 95% CI 7.49, 14.03; p= 0.0055) and dieldrin (GM 17.38, 95% CI 12.78 23.62 vs. 8.10, 95% CI 5.47, 12.00; p= 0.0034) than did children in rural, farmworker families. These results support the position that pesticides are ubiquitous in the living environment for children in vulnerable, immigrant communities, and argue for greater effort in documenting the widespread nature of pesticide exposure among children, with greater effort to reduce pesticide exposure.

Improvements in identification and quantitation of alkylated PAHs and forensic ratio sourcing.

Parent and alkylated polycyclic aromatic hydrocarbons (PAHs) are present in a number of different sources in varying proportions depending on the source material and weathering. This range of PAH sources can make it difficult to determine the origin of exposure(s). Ratios of alkylated and parent PAHs have been applied as a forensic tool to distinguish between different sources. However, few studies have examined PAH ratios comprehensively as indicators for sourcing beyond a single study area or matrix type. In this paper, we introduce an expanded analytical method based on ASTM D7363-13a which we adapted for a gas chromatography triple quadrupole mass spectrometry instrument. The modifications increase selectivity and sensitivity compared to the ASTM method. We added five alkylated series to the method. This method has then been applied to 22 independent forensic ratios. We evaluated the method and the forensic ratios with certified reference materials and known environmental samples. This analytical method and thirteen PAH ratios were found to accurately predict sources of PAHs.

A passive sampling model to predict PAHs in butter clams (Saxidomus giganteus), a traditional food source for Native American tribes of the Salish Sea Region.

Native Americans face disproportionate exposures to environmental pollution through traditional subsistence practices including shellfish harvesting. In this study, the collection of butter clams (Saxidomus giganteus) was spatially and temporally paired with deployment of sediment pore water passive samplers at 20 locations in the Puget Sound region of the Salish Sea in the Pacific Northwest, USA, within adjudicated usual and accustomed tribal fishing grounds and stations. Clams and passive samplers were analyzed for 62 individual PAHs. A linear regression model was constructed to predict PAH concentrations in the edible fraction of butter clams from the freely dissolved fraction (Cfree) in porewater. PAH concentrations can be predicted within a factor of 1.9 ±â€¯0.2 on average from the freely dissolved PAH concentration in porewater using the following equation: PAHClam=4.1±0.1×PAHporewater This model offers a simplified, cost effective, and low impact approach to assess contaminant levels in butter clams which are an important traditional food.

Discovery of common chemical exposures across three continents using silicone wristbands.

To assess differences and trends in personal chemical exposure, volunteers from 14 communities in Africa (Senegal, South Africa), North America (United States (U.S.)) and South America (Peru) wore 262 silicone wristbands. We analysed wristband extracts for 1530 unique chemicals, resulting in 400 860 chemical data points. The number of chemical detections ranged from 4 to 43 per wristband, with 191 different chemicals detected, and 1339 chemicals were not detected in any wristband. No two wristbands had identical chemical detections. We detected 13 potential endocrine disrupting chemicals in over 50% of all wristbands and found 36 chemicals in common between chemicals detected in three geographical wristband groups (Africa, North America and South America). U.S. children (less than or equal to 11 years) had the highest percentage of flame retardant detections compared with all other participants. Wristbands worn in Texas post-Hurricane Harvey had the highest mean number of chemical detections (28) compared with other study locations (10-25). Consumer product-related chemicals and phthalates were a high percentage of chemical detections across all study locations (36-53% and 18-42%, respectively). Chemical exposures varied among individuals; however, many individuals were exposed to similar chemical mixtures. Our exploratory investigation uncovered personal chemical exposure trends that can help prioritize certain mixtures and chemical classes for future studies.

Determinants of pesticide concentrations in silicone wristbands worn by Latina adolescent girls in a California farmworker community: The COSECHA youth participatory action study.

Personal exposure to pesticides has not been well characterized, especially among adolescents. We used silicone wristbands to assess pesticide exposure in 14 to 16 year old Latina girls (N = 97) living in the agricultural Salinas Valley, California, USA and enrolled in the COSECHA (CHAMACOS of Salinas Examining Chemicals in Homes and Agriculture) Study, a youth participatory action study in an agricultural region of California. We determined pesticide concentrations (ng/g/day) in silicone wristbands worn for one week using gas chromatography electron capture detection and employed gas chromatography mass spectrometry to determine the presence or absence of over 1500 chemicals. Predictors of pesticide detections and concentrations were identified using logistic regression, Wilcoxon rank sum tests, and Tobit regression models. The most frequently detected pesticides in wristbands were fipronil sulfide (87%), cypermethrin (56%), dichlorodiphenyldichloroethylene (DDE) (56%), dacthal (53%), and trans-permethrin (52%). Living within 100 m of active agricultural fields, having carpeting in the home, and having an exterminator treat the home in the past six months were associated with higher odds of detecting certain pesticides. Permethrin concentrations were lower for participants who cleaned their homes daily (GM: 1.9 vs. 6.8 ng/g/day, p = 0.01). In multivariable regression models, participants with doormats in the entryway of their home had lower concentrations (p < 0.05) of cypermethrin (87%), permethrin (99%), fipronil sulfide (69%) and DDE (75%). The results suggest that both nearby agricultural pesticide use and individual behaviors are associated with pesticide exposures.

Artificial turf: chemical flux and development of silicone wristband partitioning coefficients.

This work provides the first quantitative measure of in situ flux of semi-volatile contaminants on artificial turf fields. Passive samplers were used to identify gas-phase PAHs and OPAHs not previously reported associated with artificial turf. Utilizing a broad and targeted screen, we assess both artificial turf and from crumb rubber for 1,529 chemicals, including several with known health effects including benzo[c]fluorene. We also report the presence of 25 chemicals that have not yet been reported in artificial turf literature, including some with known effects on human health. This is the first report of bioavailable gas-phase PAH and OPAH concentrations on an outdoor field, to date gas-phase concentrations have only been reported from indoor facilities. Turf air and air were highly correlated at all three sites, and particularly at the recently-installed indoor site. Finally, thermal extraction and silicone passive samplers are highly suitable for larger-scale sampling campaigns that aim for less solvent and sample processing. We demonstrate for the first time that silicone passive samplers can be used to quantify volatile and semi-volatile organic chemicals from artificial turf. Co-deploying silicone passive samplers and conventional low density polyethylene, we develop partitioning coefficients that can be used for silicone passive air sampling environmental assessment.

Environmental and individual PAH exposures near rural natural gas extraction.

Natural gas extraction (NGE) has expanded rapidly in the United States in recent years. Despite concerns, there is little information about the effects of NGE on air quality or personal exposures of people living or working nearby. Recent research suggests NGE emits polycyclic aromatic hydrocarbons (PAHs) into air. This study used low-density polyethylene passive samplers to measure concentrations of PAHs in air near active (n = 3) and proposed (n = 2) NGE sites. At each site, two concentric rings of air samplers were placed around the active or proposed well pad location. Silicone wristbands were used to assess personal PAH exposures of participants (n = 19) living or working near the sampling sites. All samples were analyzed for 62 PAHs using GC-MS/MS, and point sources were estimated using the fluoranthene/pyrene isomer ratio. ∑PAH was significantly higher in air at active NGE sites (Wilcoxon rank sum test, p < 0.01). PAHs in air were also more petrogenic (petroleum-derived) at active NGE sites. This suggests that PAH mixtures at active NGE sites may have been affected by direct emissions from petroleum sources at these sites. ∑PAH was also significantly higher in wristbands from participants who had active NGE wells on their properties than from participants who did not (Wilcoxon rank sum test, p < 0.005). There was a significant positive correlation between ∑PAH in participants' wristbands and ∑PAH in air measured closest to participants' homes or workplaces (simple linear regression, p < 0.0001). These findings suggest that living or working near an active NGE well may increase personal PAH exposure. This work also supports the utility of the silicone wristband to assess personal PAH exposure.

Silicone wristbands compared with traditional polycyclic aromatic hydrocarbon exposure assessment methods.

Currently there is a lack of inexpensive, easy-to-use technology to evaluate human exposure to environmental chemicals, including polycyclic aromatic hydrocarbons (PAHs). This is the first study in which silicone wristbands were deployed alongside two traditional personal PAH exposure assessment methods: active air monitoring with samplers (i.e., polyurethane foam (PUF) and filter) housed in backpacks, and biological sampling with urine. We demonstrate that wristbands worn for 48 h in a non-occupational setting recover semivolatile PAHs, and we compare levels of PAHs in wristbands to PAHs in PUFs-filters and to hydroxy-PAH (OH-PAH) biomarkers in urine. We deployed all samplers simultaneously for 48 h on 22 pregnant women in an established urban birth cohort. Each woman provided one spot urine sample at the end of the 48-h period. Wristbands recovered PAHs with similar detection frequencies to PUFs-filters. Of the 62 PAHs tested for in the 22 wristbands, 51 PAHs were detected in at least one wristband. In this cohort of pregnant women, we found more significant correlations between OH-PAHs and PAHs in wristbands than between OH-PAHs and PAHs in PUFs-filters. Only two comparisons between PAHs in PUFs-filters and OH-PAHs correlated significantly (rs = 0.53 and p = 0.01; rs = 0.44 and p = 0.04), whereas six comparisons between PAHs in wristbands and OH-PAHs correlated significantly (rs = 0.44 to 0.76 and p = 0.04 to <0.0001). These results support the utility of wristbands as a biologically relevant exposure assessment tool which can be easily integrated into environmental health studies. Graphical abstract PAHs detected in samples collected from urban pregnant women.

Development of quantitative screen for 1550 chemicals with GC-MS.

With hundreds of thousands of chemicals in the environment, effective monitoring requires high-throughput analytical techniques. This paper presents a quantitative screening method for 1550 chemicals based on statistical modeling of responses with identification and integration performed using deconvolution reporting software. The method was evaluated with representative environmental samples. We tested biological extracts, low-density polyethylene, and silicone passive sampling devices spiked with known concentrations of 196 representative chemicals. A multiple linear regression (R2 = 0.80) was developed with molecular weight, logP, polar surface area, and fractional ion abundance to predict chemical responses within a factor of 2.5. Linearity beyond the calibration had R2 > 0.97 for three orders of magnitude. Median limits of quantitation were estimated to be 201 pg/µL (1.9× standard deviation). The number of detected chemicals and the accuracy of quantitation were similar for environmental samples and standard solutions. To our knowledge, this is the most precise method for the largest number of semi-volatile organic chemicals lacking authentic standards. Accessible instrumentation and software make this method cost effective in quantifying a large, customizable list of chemicals. When paired with silicone wristband passive samplers, this quantitative screen will be very useful for epidemiology where binning of concentrations is common. Graphical abstract A multiple linear regression of chemical responses measured with GC-MS allowed quantitation of 1550 chemicals in samples such as silicone wristbands.

Preparation and performance features of wristband samplers and considerations for chemical exposure assessment.

Wristbands are increasingly used for assessing personal chemical exposures. Unlike some exposure assessment tools, guidelines for wristbands, such as preparation, applicable chemicals, and transport and storage logistics, are lacking. We tested the wristband's capacity to capture and retain 148 chemicals including polychlorinated biphenyls (PCBs), pesticides, flame retardants, polycyclic aromatic hydrocarbons (PAHs), and volatile organic chemicals (VOCs). The chemicals span a wide range of physical-chemical properties, with log octanol-air partitioning coefficients from 2.1 to 13.7. All chemicals were quantitatively and precisely recovered from initial exposures, averaging 102% recovery with relative SD ≤21%. In simulated transport conditions at +30 °C, SVOCs were stable up to 1 month (average: 104%) and VOC levels were unchanged (average: 99%) for 7 days. During long-term storage at -20 °C up to 3 (VOCs) or 6 months (SVOCs), all chemical levels were stable from chemical degradation or diffusional losses, averaging 110%. Applying a paired wristband/active sampler study with human participants, the first estimates of wristband-air partitioning coefficients for PAHs are presented to aid in environmental air concentration estimates. Extrapolation of these stability results to other chemicals within the same physical-chemical parameters is expected to yield similar results. As we better define wristband characteristics, wristbands can be better integrated in exposure science and epidemiological studies.