An unrecognized source of PCB contamination in schools and other buildings

Selective dopaminergic neurotoxicity modulated by inherent cell-type specific neurobiology

Parkinson's disease (PD) is a debilitating neurodegenerative disease affecting millions of individuals worldwide. Hallmark features of PD pathology are the formation of Lewy bodies in neuromelanin-containing dopaminergic (DAergic) neurons of the substantia nigra pars compacta (SNpc), and the subsequent irreversible death of these neurons. Although genetic risk factors have been identified, around 90 % of PD cases are sporadic and likely caused by environmental exposures and gene-environment interaction. Mechanistic studies have identified a variety of chemical PD risk factors. PD neuropathology occurs throughout the brain and peripheral nervous system, but it is the loss of DAergic neurons in the SNpc that produce many of the cardinal motor symptoms. Toxicology studies have found specifically the DAergic neuron population of the SNpc exhibit heightened sensitivity to highly variable chemical insults (both in terms of chemical structure and mechanism of neurotoxic action). Thus, it has become clear that the inherent neurobiology of nigral DAergic neurons likely underlies much of this neurotoxic response to broad insults. This review focuses on inherent neurobiology of nigral DAergic neurons and how such neurobiology impacts the primary mechanism of neurotoxicity. While interactions with a variety of other cell types are important in disease pathogenesis, understanding how inherent DAergic biology contributes to selective sensitivity and primary mechanisms of neurotoxicity is critical to advancing the field. Specifically, key biological features of DAergic neurons that increase neurotoxicant susceptibility.

Gut toxicity of polystyrene microplastics and polychlorinated biphenyls to Eisenia fetida: Single and co-exposure effects with a focus on links between gut bacteria and bacterial translocation stemming from gut barrier damage

Microplastics' (MPs) ability to sorb and transport polychlorinated biphenyls (PCBs) in soil ecosystems warrants significant attention. Although organisms mainly encounter pollutants through the gut, the combined pollution impact of MPs and PCBs on soil fauna gut toxicity remains incompletely understood. Consequently, this study examined the gut toxicity of polystyrene MPs (PS-MPs) and PCB126 on Eisenia fetida, emphasizing the links between gut bacteria and bacterial translocation instigated by gut barrier impairment. Our findings underscored that E. fetida could ingest PS-MPs, which mitigated the PCB126 accumulation in E. fetida by 9.43 %. Exposure to PCB126 inhibited the expression of gut tight junction (TJ) protein genes. Although the presence of PS-MPs attenuated this suppression, it didn't alleviate gut barrier damage and bacterial translocation in the co-exposure group. This group demonstrated a significantly increased level of gut bacterial load (BLT, ANOVA, p = 0.005 vs control group) and lipopolysaccharide-binding protein (LBP, ANOVA, all p < 0.001 vs control, PCB, and PS groups), both of which displayed significant positive correlations with antibacterial defense. Furthermore, exposure to PS-MPs and PCB126, particularly within the co-exposure group, results in a marked decline in the dispersal ability of gut bacteria. This leads to dysbiosis (Adonis, R2 = 0.294, p = 0.001), with remarkable signature taxa such as Janthinobacterium, Microbacterium and Pseudomonas, being implicated in gut barrier dysfunction. This research illuminates the mechanism of gut toxicity induced by PS-MPs and PCB126 combined pollution in earthworms, providing novel insights for the ecological risk assessment of soil.

Polychlorinated Biphenyls and Semen Quality in Healthy Young Men Living in a Contaminated Area

Polychlorinated biphenyls (PCBs) are persistent organic pollutants and endocrine disruptors that have been implicated in potential damage to human semen. However, the studies conducted so far provide contrasting results. Our study aimed to investigate the associations between PCB serum and semen levels and semen quality in high school and university students living in a highly PCB-polluted area of Italy. Subjects with a normal body mass index who did not make daily use of tobacco, alcohol, drugs, or medication were selected. All participants provided a fasting blood and a semen sample. Gas chromatography-mass spectrometry was used to determine the concentrations of 26 PCB congeners. The concentrations of PCB functional groups and total PCBs were also computed. A total of 143 subjects (median age 20, range 18-22 years) were enrolled. The median total PCB concentrations were 3.85 ng/mL (range 3.43-4.56 ng/mL) and 0.29 ng/mL (range 0.26-0.32 ng/mL) in serum and semen, respectively. The analysis of the associations between sperm PCB concentration and semen parameters showed (a) negative associations between some PCB congeners, functional groups and total PCBs and sperm total motility; (b) negative associations of total PCBs with sperm normal morphology; and (c) no association of PCBs with sperm concentration. Subjects at the highest quartile of semen total PCB concentration had 19% and 23% mean reductions in total motility and normal morphology, respectively, compared to those at the lowest quartile. The analysis of the associations of serum PCB levels with sperm parameters yielded null or mixed (some positive, other negative) results. In conclusion, the present study provides evidence of a negative effect of some PCB congeners and total PCBs in semen on sperm motility and normal morphology. However, the associations between the concentration of serum and semen PCB congeners and functional groups and sperm quality parameters were inconsistent.

Polyurethane Foam Emission Samplers to Identify Sources of Airborne Polychlorinated Biphenyls from Glass-Block Windows and Other Room Surfaces in a Vermont School

We hypothesized that emissions of polychlorinated biphenyls (PCBs) from Aroclor mixtures present in building materials explain their concentrations in school air. Here, we report a study of airborne concentrations and gas-phase emissions in three elementary school rooms constructed in 1958. We collected airborne PCBs using polyurethane foam passive air samplers (PUF-PAS, n = 6) and PCB emissions from building materials using polyurethane foam passive emission samplers (PUF-PES, n = 17) placed over flat surfaces in school rooms, including vinyl tile floors, carpets, painted bricks, painted drywall, and glass-block windows. We analyzed all 209 congeners represented in 173 chromatographic separations and found that the congener distribution in PUF-PES strongly resembled the predicted diffusive release of gas-phase PCBs from a solid material containing Aroclor 1254. Concentrations of airborne total PCBs ranged from 38 to 180 ng m-3, a range confirmed by an independent laboratory in the same school. These levels exceed action levels for all aged children set by the State of Vermont and exceed guidance levels set by the U.S. EPA for children under age 3. Emissions of PCBs from the glass-block windows (30,000 ng m-2 d-1) greatly exceeded those of all other surfaces, which ranged from 35 to 2700 ng m-2 d-1. This study illustrates the benefit of the direct measurement of PCB emissions to identify the most important building remediation needed to reduce airborne PCB concentrations in schools.

Congener-Specific Emissions from Floors and Walls Characterize Indoor Airborne Polychlorinated Biphenyls

To reconcile the federal regulation of material polychlorinated biphenyl (PCB) concentrations with recently implemented state regulations of airborne PCBs, there is a need to characterize the relationship between PCB emissions from surfaces and air concentrations. We hypothesized that the magnitude and congener distribution of emissions from floors and walls fully account for the airborne PCBs measured in rooms constructed during the height of PCB production and sales. We measured emissions of PCB congeners from various wall and floor materials using polyurethane foam passive emission samplers before and after hexane wiping. Our results revealed that PCB emissions from flooring adequately predicted the magnitude and congener distribution of PCBs observed in the room air. Emissions varied by material within a single building (5 × 103 ng m-2 day-1 from wood panel walls to 3 × 104 ng m-2 day-1 from vinyl tile) and within the same room. Yet congener distributions between material emission PCB profiles and room air PCB profiles were statistically similar. Hexane wiping significantly reduced PCB emissions (>60%), indicating the importance of surface films as an ongoing source of airborne PCBs. The magnitude and congener distribution of material bulk concentrations did not explain that of material emissions or air concentrations. Passive measurements of polychlorinated biphenyl emissions from floors in a university building predict the concentrations of PCBs in room air.

Persistent Organic Contaminants in Dust from the International Space Station

Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), "novel" brominated flame retardants (NBFRs), organophosphate esters (OPEs), polycyclic aromatic hydrocarbons (PAH), perfluoroalkyl substances (PFAS), and polychlorinated biphenyls (PCBs) were measured in a composite sample of dust from the International Space Station (ISS). Notwithstanding the unique environment from which the dust originated, while concentrations of all target compound classes frequently exceeded the median values in terrestrial indoor microenvironments in the US and western Europe, ISS dust concentrations were generally within the terrestrial range. The relative abundance of the three HBCDD diastereomers is dominated by γ-HBCDD (96.6% ΣHBCDD). This matches very closely with the commercial mixture added to materials and contrasts with the diastereomer distribution observed in most terrestrial indoor dust samples (in which γ-HBCDD is typically ∼60-70% ΣHBCDD). This suggests conditions inside the ISS do not favor the previously reported photolytically mediated formation in dust of α-HBCDD. Also of note, the concentration of perfluorooctanoic acid (PFOA) in ISS dust (3300 ng/g) exceeds the maximum reported (1960 ng/g) in a 2008 survey of dust from US child daycare centers and homes. This may reflect the widespread use of waterproofing treatments in the ISS to prevent microbial growth. Our findings can inform future material choices for manned spacecraft such as the ISS.

Structure-Activity Relationship of Lower Chlorinated Biphenyls and Their Human-Relevant Metabolites for Astrocyte Toxicity

Exposure to polychlorinated biphenyls (PCBs) is associated with developmental neurotoxicity and neurodegenerative disorders; however, the underlying mechanisms of pathogenesis are unknown. Existing literature has focused mainly on using neurons as a model system to study mechanisms of PCB-mediated neurotoxicity, overlooking the role of glial cells, such as astrocytes. As normal brain function is largely astrocyte-dependent, we hypothesize that astrocytes play an important role in PCB-mediated injury to neurons. We assessed the toxicity of two commercial PCB mixtures, Aroclor 1016 and Aroclor 1254, and a non-Aroclor PCB mixture found in residential air called the Cabinet mixture, all of which contain lower chlorinated PCBs (LC-PCBs) found in indoor and outdoor air. We further assessed the toxicity of five abundant airborne LC-PCBs and their corresponding human-relevant metabolites in vitro models of astrocytes, namely, the C6 cell line and primary astrocytes isolated from Sprague-Dawley rats and C57BL/6 mice. PCB52 and its human-relevant hydroxylated and sulfated metabolites were found to be the most toxic compounds. No significant sex-dependent cell viability differences were observed in rat primary astrocytes. Based on the equilibrium partitioning model, it was predicted that the partitioning of LC-PCBs and their corresponding metabolites in biotic and abiotic compartments of the cell culture system is structure-dependent and that the observed toxicity is consistent with this prediction. This study, for the first time, shows that astrocytes are sensitive targets of LC-PCBs and their human-relevant metabolites and that further research to identify mechanistic targets of PCB exposure in glial cells is necessary.

Comparison of pollution status and source apportionment for PCBs and OCPs of indoor dust from an industrial city

In this study, the pollution status of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) was investigated in indoor and outdoor dust from three different functional areas of Hefei, China. The relationship between the concentrations of PCBs and OCPs and different influencing factors in dwellings was studied. The results showed that the concentrations of PCBs and OCPs were higher in samples from dwellings with higher smoking frequency, lower cleaning frequency, higher floors and smaller household size. The results of Spearman's correlation coefficient analysis indicated that PCBs and OCPs were not consistently associated with each other, while sources of low-chlorinated PCBs and high-chlorinated PCBs were different. Scanning electron microscopy (SEM) shows the shape of indoor dust was a mixture of blocky, flocculated, spherical structures, and irregular shapes. The results of principal component analysis (PCA) and positive matrix factorization model (PMF) showed that the PCBs and OCPs of indoor dust came from both indoor and outdoor sources between local and regional transport. Carbon (δ¹³C) and Nitrogen (δ¹⁵N) stable isotope results indicate or show that the indoor dust (δ¹³C: - 24.37‰, δ¹⁵N: 6.88‰) and outdoor dust (δ¹³C: - 12.65‰, δ¹⁵N: 2.558‰) is derived from fossil fuel, coal combustion, road dust, fly ash, C4 biomass and soil. Potential source contribution factor (PSCF) and concentration weighted-trajectory analysis suggest that sources of pollutants were local and regional transport from surrounding provinces and marine emissions. The average daily dose (adult: 8.20E-04, children: 2.37E-03) of pollutants and the carcinogenic risks (adult: 1.23E-02, children: 2.65E-02) were relatively greater for children than adults. This study demonstrates the utility of SEM to characterize indoor dust morphology while combining PMF, PSCF, and stable isotope methods in identifying indoor PCBs and OCPs sources and regions.

Toxicity Impacts on Human Adipose Mesenchymal Stem/Stromal Cells Acutely Exposed to Aroclor and Non-Aroclor Mixtures of Polychlorinated Biphenyl

Polychlorinated biphenyl (PCB) accumulates in adipose where it may impact the growth and function of cells within the tissue. This is particularly concerning during adolescence when adipocytes expand rapidly. Herein, we sought to understand how exposure to PCB mixtures found in U.S. schools affects human adipose mesenchymal stem/stromal cell (MSC) health and function. We investigated how exposure to Aroclor 1016 and Aroclor 1254, as well as a newly characterized non-Aroclor mixture that resembles the PCB profile found in cabinets, Cabinet Mixture, affects adipose MSC growth, viability, and function in vitro. We found that exposure to all three mixtures resulted in two distinct types of toxicity. At PCB concentrations >20 μM, the majority of MSCs die, while at 1-10 μM, MSCs remained viable but display numerous alterations to their phenotype. At these sublethal concentrations, the MSC rate of expansion slowed and morphology changed. Further assessment revealed that PCB-exposed MSCs had impaired adipogenesis and a modest decrease in immunosuppressive capabilities. Thus, exposure to PCB mixtures found in schools negatively impacts the health and function of adipose MSCs. This work has implications for human health due to MSCs' role in supporting the growth and maintenance of adipose tissue.

A Review of Polychlorinated Biphenyls (PCBs) Pollution in the Air: Where and How Much Are We Exposed to?

Polychlorinated biphenyls (PCBs) were widely used in industrial and commercial applications, until they were banned in the late 1970s as a result of their significant environmental pollution. PCBs in the environment gained scientific interest because of their persistence and the potential threats they pose to humans. Traditionally, human exposure to PCBs was linked to dietary ingestion. Inhalational exposure to these contaminants is often overlooked. This review discusses the occurrence and distribution of PCBs in environmental matrices and their associated health impacts. Severe PCB contamination levels have been reported in e-waste recycling areas. The occurrence of high PCB levels, notably in urban and industrial areas, might result from extensive PCB use and intensive human activity. Furthermore, PCB contamination in the indoor environment is ten-fold higher than outdoors, which may present expose risk for humans through the inhalation of contaminated air or through the ingestion of dust. In such settings, the inhalation route may contribute significantly to PCB exposure. The data on human health effects due to PCB inhalation are scarce. More epidemiological studies should be performed to investigate the inhalation dose and response mechanism and to evaluate the health risks. Further studies should also evaluate the health impact of prolonged low-concentration PCB exposure.

The effects of Aroclor 1254 alone and in combination with X-rays on the male mice germ cells quantity and quality

The effects of chemical and physical environmental factors are concerned as the main reason of diminished male fertility. The aim of the study was the investigation of the effects of low doses of Aroclor 1254 or combined exposure to low doses of Aroclor 1254 and low doses of ionizing radiation on the sperm quantity and quality of male germ cells including damage to genetic material of adult male mice. Mice were exposed for 2 weeks, 3 times per week by intraperitoneal injection with Aroclor 1254 diluted in corn oil at doses of 1, 2 and 4 mg/kg bw or to whole body X-rays irradiation at doses 0.05 Gy, 0.10 Gy and 0.15 Gy or to combination of X-rays and Aroclor 1254 at following doses 0.05 Gy + 1 mg/kg bw Aroclor 1254, 0.10 Gy + 2 mg/kg bw Aroclor 1254. The samples for sperm count, motility, morphology and DNA integrity of male germ cells estimation were taken from animals just after the end of exposure and 5 weeks later. Irradiation alone deteriorated sperm count and quality. Aroclor 1254 significantly reduced the sperm motility and increased sperm abnormality and at the highest dose also induced DNA damage of gametes. The combined exposure to 0.10 Gy + 2 mg/kg bw of Aroclor 1254 showed the increase in the sperm concentration and the decrease of percentage of abnormal spermatozoa compared to results after irradiation to 0.10 Gy alone. In conclusion, the low doses of Aroclor 1254 used in this study did not significantly reduce the sperm count, but affected the sperm motility, morphology and sometimes also DNA integrity of gametes. In combination with low doses of irradiation, low doses of Aroclor 1254 may ameliorate the harmful effect of irradiation on the male gametes.

Polychlorinated Biphenyls (PCBs) in the Environment: Occupational and Exposure Events, Effects on Human Health and Fertility

In the last decade or so, polychlorinated biphenyls (PCBs) garnered renewed attention in the scientific community due to new evidence pointing at their continued presence in the environment and workplaces and the potential human risks related to their presence. PCBs move from the environment to humans through different routes; the dominant pathway is the ingestion of contaminated foods (fish, seafood and dairy products), followed by inhalation (both indoor and outdoor air), and, to a lesser extent, dust ingestion and dermal contact. Numerous studies reported the environmental and occupational exposure to these pollutants, deriving from building materials (flame-retardants, plasticizers, paints, caulking compounds, sealants, fluorescent light ballasts, etc.) and electrical equipment. The highest PCBs contaminations were detected in e-waste recycling sites, suggesting the need for the implementation of remediation strategies of such polluted areas to safeguard the health of workers and local populations. Furthermore, a significant correlation between PCB exposure and increased blood PCB concentrations was observed in people working in PCB-contaminated workplaces. Several epidemiological studies suggest that environmental and occupational exposure to high concentrations of PCBs is associated with different health outcomes, such as neuropsychological and neurobehavioral deficits, dementia, immune system dysfunctions, cardiovascular diseases and cancer. In addition, recent studies indicate that PCBs bioaccumulation can reduce fertility, with harmful effects on the reproductive system that can be passed to offspring. In the near future, further studies are needed to assess the real effects of PCBs exposure at low concentrations for prolonged exposure in workplaces and specific indoor environments.

Persistent Problem: Global Challenges to Managing PCBs

Polychlorinated biphenyls (PCBs), "famous" as persistent organic pollutants (POPs), have been managed nationally since the 1970s and globally under the Stockholm Convention on POPs since 2004, requiring environmentally sound management (ESM) of PCBs by 2028. At most, 30% of countries are on track to achieve ESM by 2028. Globally over 10 million tonnes of PCB-containing materials remain, mostly in countries lacking the ability to manage PCB waste. Canada (Ontario) and Czechia, both parties to the Stockholm Convention, are close to achieving the 2028 goal, having reduced their stocks of pure PCBs by 99% in the past 10 years. In contrast, the USA, not a party to the Stockholm Convention, continues to have a substantial but poorly inventoried stock of PCBs and only ∼3% decrease in mass of PCBs since 2006. PCB management, which depends on Stockholm Convention support and national compliance, portends major challenges for POP management. The failure to manage global PCB stocks >30 years after the end of production highlights the urgent need to prioritize reducing production and use of newer, more widely distributed POPs such as chlorinated paraffins and per- and polyfluorinated alkyl substances, as these management challenges are unlikely to be resolved in the coming decades.

Occupational exposure to polychlorinated biphenyls (PCBs) in workers at companies in the Colombian electricity sector

Polychlorinated biphenyls (PCBs) comprise a family of 209 congeners that have low electrical conductivity and high thermal resistance due to their physicochemical properties and are thus widely used as dielectric oils, among other applications. Although PCBs are no longer used in dielectric oils in Colombia as of several years ago, electric transformers in Colombia might still contain PCBs, and workers might carry PCBs due to exposure from when they were still used in dielectric fluid. Thus, occupational exposure in Colombia to PCBs was evaluated by determining their concentrations in the blood plasma samples of 115 workers in the electricity sector . The sum of the six PCB indicators was between <LOD and 16.09 µg L^-1 (median: <0.10 µg L^-1, 95^th percentile: 1.30 µg L^-1), and the total concentration of PCBs calculated as PCB 138 + 153 + 180 × 1.7 was between <LOD and 3210.17 ng g^-1 lipids (median: <7.30 ng g^-1 , 95^th percentile: 392.79 ng g^-1). . One worker dedicated to transformer and capacitor maintenance activities presented a PCB value higher than the biological tolerance level of 15 µg L^-1. The findings of the present investigation revealed that workers in the electricity sector face chronic occupational exposure to PCBs; Finally, the results can help to improve health policies related to these contaminants in the country.

Accumulation of polychlorinated biphenyls in fabrics in a contaminated building, and the effect of laundering

This research investigates sorption of PCBs to fabrics in a contaminated indoor environment and the effect of laundering on PCB removal from the fabrics. Eight articles of clothing were exposed to the air in a PCB-contaminated building. The background air concentration was 670 ng/m³ PCB_total with PCB-52 being the main congener. Air and fabric samples were collected for analysis before and periodically throughout the experiment. After 25 weeks, the remaining fabrics were washed and cut into three pieces each. One part was dried in the contaminated building, second in a PCB-free building and third in a mechanical drier. The PCB mass concentration increased during the first 6-10 weeks for all investigated fabrics, after which some fabrics approached equilibrium for more volatile congeners. Mass-normalized cloth-air partition coefficients were quantified for 9 congeners; for PCB-52, these ranged from 10^6.1 to 10^7.0 which were consistent with previously reported values. Partition coefficients of PCBs were observed to increase with their respective octanol-air partition coefficients. Washing and drying clothes resulted in the removal between 22% and 84% of PCBs. There was no difference in removal percentage after air-drying in clean or contaminated air. Drying in a mechanical drier removed significantly more PCBs than air-drying.

Comparative transcriptomic analysis reveals reproductive impairments caused by PCBs and OH-PCBs through the dysregulation of ER and AR signaling

Reports have highlighted the presence of PCBs and their metabolites, OH-PCBs, in human serum as well as their endocrine-disrupting effects on reproductive function through direct interactions with the androgen receptor (AR) and estrogen receptor (ER). However, the molecular mechanisms directly linking the actions of PCBs and OH-PCBs on the AR and ER to induce reproductive impairment remain poorly understood. In this study, we characterized the cellular response to PCBs and OH-PCBs acting on AR and ER transactivation at the transcriptome level coupled with bioinformatics analysis to identify the downstream pathways of androgen and estrogen signaling that leads to reproductive dysfunction. We first confirmed the agonistic and antagonistic effects of several PCBs and OH-PCBs on AR- and ER-mediated reporter gene activity using the androgen-responsive LNCaP and estrogen-responsive MCF-7 cell lines, respectively. Anti-estrogenic activity was not detected among the tested compounds; however, we found that in addition to anti-androgenic and estrogenic activity, PCB 28 and PCB 138 exhibited androgenic activity, while most of the tested OH-PCBs showed a synergistic effect on DHT-mediated transactivation of the AR. Bioinformatics analysis of transcriptome profiles from selected PCBs and OH-PCBs revealed various pathways that were dysregulated depending on their agonistic, antagonistic, or synergistic effects. The OH-PCBs with estrogenic activity affected pathways including vitamin metabolism and calcium transport. Other notable dysregulated pathways include cholesterol transport in response to androgenic PCBs, thyroid hormone metabolism in response to anti-androgenic PCBs, and antioxidant pathways in response to androgen-synergistic OH-PCBs. Our results demonstrate that PCBs and OH-PCBs directly alter specific pathways through androgen- or estrogen-mediated signaling, thereby providing additional insights into the mechanisms by which these compounds cause reproductive dysfunction.

Temporal trend of polychlorinated biphenyls contamination in the northwestern Arabian Gulf - Evidence from sediment records

This study provides an insight into the polychlorinated biphenyls (PCBs) inventories in the sediments of the northwestern Arabian/Persian Gulf. PCBs can be used as chemical markers that correlate with historical events in the region, to estimate the sedimentation rates in the northern Gulf, and to determine the sources of pollutants in the study area. The concentrations of PCBs were generally patchy in sediments. At Station 1 the ΣPCB concentrations generally fluctuated between 0.100 and 0.400 ng g^-1 dw throughout the depositional history measured in a sediment core. There were four peaks in the ΣPCB profile corresponding to 1969, 1979, 1983 and 1991. Station 2 showed a prominent peak at depth of 25 cm. The concentrations of the ΣPCBs and ΣICE congeners at this depth were 28 and 12 ng g^-1 dw respectively. Concentrations then dropped dramatically thereafter by a factor of 4. The ΣPCB concentrations at Station 3 were very low compared to the concentrations measured at Stations 1 and 2. The PCB concentration in Core 4 which was taken from open waters was 2-3 orders of magnitude lower than those in the other coastal cores. However, a 1990-91 peak was omnipresent in these cores. There is no record of PCB production within the Gulf region, and PCB releases into the Kuwait marine environment are likely to originate from their use in products. These maxima in early-1990s can be correlated to inputs from war-related activities, including the reported destruction of PCB-containing transformers and military equipment during the occupation of Kuwait. None of the recent sediment core sections at the four stations had a ΣPCB concentration near the effects range-median (ERM) concentration of 180 ng g^-1, or permissible exposure limits (PEL) of 189 ng g^-1, or were above the effect range-low (ERL) values of 22.7 ng g^-1.

Human hepatic microsomal sulfatase catalyzes the hydrolysis of polychlorinated biphenyl sulfates: A potential mechanism for retention of hydroxylated PCBs

Polychlorinated biphenyls (PCBs) are persistent environmental contaminants that continue to be of concern due to their varied toxicities. Upon human exposure, many PCBs with lower numbers of chlorine atoms are metabolized to hydroxylated derivatives (OH-PCBs), and cytosolic sulfotransferases can subsequently catalyze the formation of PCB sulfates. Recent studies have indicated that PCB sulfates bind reversibly with a high affinity to human serum proteins, and that they are also taken up by cells and tissues. Since PCB sulfates might be hydrolyzed to the more toxic OH-PCBs, we have investigated the ability of human hepatic microsomal sulfatase to catalyze this reaction. Twelve congeners of PCB sulfates were substrates for the microsomal sulfatase with catalytic rates exceeding that of dehydroepiandrosterone sulfate as a comparison substrate for steroid sulfatase (STS). These results are consistent with an intracellular mechanism for sulfation and de-sulfation that may contribute to retention and increased time of exposure to OH-PCBs.

Chemical contaminant exposures assessed using silicone wristbands among occupants in office buildings in the USA, UK, China, and India

Little is known about chemical contaminant exposures of office workers in buildings globally. Complex mixtures of harmful chemicals accumulate indoors from building materials, building maintenance, personal products, and outdoor pollution. We evaluated exposures to 99 chemicals in urban office buildings in the USA, UK, China, and India using silicone wristbands worn by 251 participants while they were at work. Here, we report concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and other brominated flame retardants (BFRs), organophosphate esters (OPEs), phthalates and phthalate alternatives, pesticides, and polycyclic aromatic hydrocarbons (PAHs). First, we found major differences in office worker chemical exposures by country, some of which can be explained by regulations and use patterns. For example, exposures to several pesticides were substantially higher in India where there were fewer restrictions and unique malaria challenges, and exposures to flame retardants tended to be higher in the USA and UK where there were historic, stringent furniture flammability standards. Higher exposures to PAHs in China and India could be due to high levels of outdoor air pollution that penetrates indoors. Second, some office workers were still exposed to legacy PCBs, PBDEs, and pesticides, even decades after bans or phase-outs. Third, we identified exposure to a contemporary PCB that is not covered under legacy PCB bans due to its presence as an unintentional byproduct in materials. Fourth, exposures to novel BFRs, OPEs, and other chemicals commonly used as substitutes to previously phased-out chemicals were ubiquitous. Fifth, some exposures were influenced by individual factors, not just countries and buildings. Phthalate exposures, for example, were related to personal care product use, country restrictions, and building materials. Overall, we found substantial country differences in chemical exposures and continued exposures to legacy phased-out chemicals and their substitutes in buildings. These findings warrant further research on the role of chemicals in office buildings on worker health.

Maternal exposure to airborne polychlorinated biphenyls (PCBs) and risk of adverse birth outcomes

Human health effects of airborne lower-chlorinated polychlorinated biphenyls (LC-PCBs) are largely unexplored. Since PCBs may cross the placenta, maternal exposure could potentially have negative consequences for fetal development. We aimed to determine if exposure to airborne PCB during pregnancy was associated with adverse birth outcomes. In this cohort study, exposed women had lived in PCB contaminated apartments at least one year during the 3.6 years before conception or the entire first trimester of pregnancy. The women and their children were followed for birth outcomes in Danish health registers. Logistic regression was performed to estimate odds ratios (OR) for changes in secondary sex ratio, preterm birth, major congenital malformations, cryptorchidism, and being born small for gestational age. We performed linear regression to estimate difference in birth weight among children of exposed and unexposed mothers. All models were adjusted for maternal age, educational level, ethnicity, and calendar time. We identified 885 exposed pregnancies and 3327 unexposed pregnancies. Relative to unexposed women, exposed women had OR 0.97 (95% CI 0.82, 1.15) for secondary sex ratio, OR 1.13 (95% CI 0.76, 1.67) for preterm birth, OR 1.28 (95% CI 0.81, 2.01) for having a child with major malformations, OR 1.73 (95% CI 1.01, 2.95) for cryptorchidism and OR 1.23 (95% CI 0.88, 1.72) for giving birth to a child born small for gestational age. The difference in birth weight for children of exposed compared to unexposed women was − 32 g (95% CI—79, 14). We observed an increased risk of cryptorchidism among boys after maternal airborne LC-PCB exposure, but due to the proxy measure of exposure, inability to perform dose–response analyses, and the lack of comparable literature, larger cohort studies with direct measures of exposure are needed to investigate the safety of airborne LC-PCB exposure during pregnancy

The impact of endocrine-disrupting chemical exposure in the mammalian hypothalamic-pituitary axis

The hypothalamic-pituitary axis (HP axis) plays a critical and integrative role in the endocrine system control to maintain homeostasis. The HP axis is responsible for the hormonal events necessary to regulate the thyroid, adrenal glands, gonads, somatic growth, among other functions. Endocrine-disrupting chemicals (EDCs) are a worldwide public health concern. There is growing evidence that exposure to EDCs such as bisphenol A (BPA), some phthalates, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and biphenyls (PBBs), dichlorodiphenyltrichloroethane (DDT), tributyltin (TBT), and atrazine (ATR), is associated with HP axis abnormalities. EDCs act on hormone receptors and their downstream signaling pathways and can interfere with hormone synthesis, metabolism, and actions. Because the HP axis function is particularly sensitive to endogenous hormonal changes, disruptions by EDCs can alter HP axis proper function, leading to important endocrine irregularities. Here, we review the evidence that EDCs could directly affect the mammalian HP axis function.

Bioaccumulation of persistent organic pollutants in the gonads of Barbus barbus (Linnaeus, 1758)

Maps with grey or even white spaces are still present in spite of the fact that persistent organic pollutants (POPs) are at the forefront of research in aquatic toxicology and environmental safety. This is also the case for the Mureș River basin. The intensive use of industrial substances such as polychlorinated biphenyls (PCBs) and pesticides such as organochlorine compounds (OCPs) has caused global contamination of the aquatic environment. In our study we have found very high concentrations of both PCBs (2110-169,000 ng/g lipid weight ΣPCB, 1950-166,000 ng/g lipid weight ΣPCB₇) and OCPs (1130-7830 ng/g lipid weight ΣDDT, 47.6-2790 ng/g lipid weight ΣHCH, 5.53-35.6 ng/g lipid weight ΣChlordane, and 6.74-158 ng/g lipid weight HCB) in the gonad tissue of Barbus barbus (Linnaeus, 1758) males and females. Contrary to most studies where the weight, length, and lipid percentage are positively correlated with the concentration of POPs from different tissue types, we observed a downward trend for the lipid normalized concentrations of some pollutants in gonads while these indices were actually increasing. The decrease of lipid normalized POPs with the increase of CF and lipid percentage may be due to the fact that individuals are eliminating hard and soft roes every year during reproduction which could mean that some quantities of pollutants are also eliminated along with the hard and soft roes. The high POPs concentrations found in our study should be a needed wakeup call for environmentalists and a starting point in developing monitoring and management measures for these pollutants.

Polychlorinated biphenyls and organochlorines pesticides in indoor dust: An exploration of sources and health exposure risk in a rural area (Kopawa) of Nepal

While contamination of indoor environment with organochlorine compounds (OCs) is well documented worldwide, only a few studies highlighted the problem of indoor pollution in Indian sub-continent, including Nepal. This study insight the contamination level, distribution pattern, and sources of OCs in indoor dust from a rural area of Nepal. Additionally, daily exposure risk through different intake pathways was estimated in order to mark the potential risk of OCs to local residents. Results indicated the predominance of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in dust. Ʃ₂₆OCPs (median 87 ng/g) in dust was about 7-8 times greater than Ʃ₃₀PCBs (median 10.5 ng/g). DDT was the most abundant chemical among Ʃ₂₆OCPs, followed by HCHs and endosulfan, and accounted for 73%, 7%, and 4% of Ʃ₂₆OCPs, respectively. A relatively high level of ƩDDT than other OCPs suggests the existence of DDT source in the Nepalese environment. Among PCB, tetra-CBs were most prevalent, trailed by penta-CBs, hexa-CBs, and hepta-CBs, and comprised 28%, 21%, 17% and 17% of Ʃ₃₀PCBs, respectively. Dioxin like-PCBs (median 3.48 ng/g) was about two times higher than the total indicator-PCB (median 1.63 ng/g). High p,p-DDT/p,p-DDE ratio (median 2.89) suggested fresh application and minimal degradation of DDT in the local environment of Kopawa. While lower α-/γ-HCH ratio (median 0.75) indicated lindane contamination as the primary sources of HCH. Moreover, the low α-/β-endosulfan ratio (median 0.86) specified the fresh use of commercial endosulfan. Among OCPs, only DDT positively related to total organic carbon (TOC) (Rho = 0.55, p < 0.05) but not black carbon (BC), proposing minimal or zero impact of TOC and BC. For PCBs, PCB-126 was moderately and negatively correlated with TOC (Rho = -0.49, p < 0.05), but not BC. The daily risk exposure (DRE) assessment showed that children are more vulnerable to OCs than the adult. The DRE of OCs in this study were 2-4 order of magnitude lower than their corresponding reference dose (RfD), proposing insignificant risk.

Fabrication and verification of a glass-silicon-glass micro-/nanofluidic model for investigating multi-phase flow in shale-like unconventional dual-porosity tight porous media

Unconventional shale or tight oil/gas reservoirs that have micro-/nano-sized dual-scale matrix pore throats with micro-fractures may result in different fluid flow mechanisms compared with conventional oil/gas reservoirs. Microfluidic models, as a potential powerful tool, have been used for decades for investigating fluid flow at the pore-scale in the energy field. However, almost all microfluidic models were fabricated by using etching methods and very few had dual-scale micro-/nanofluidic channels. Herein, we developed a lab-based, quick-processing and cost-effective fabrication method using a lift-off process combined with the anodic bonding method, which avoids the use of any etching methods. A dual-porosity matrix/micro-fracture pattern, which can mimic the topology of shale with random irregular grain shapes, was designed with the Voronoi algorithm. The pore channel width range is 3 μm to 10 μm for matrices and 100-200 μm for micro-fractures. Silicon is used as the material evaporated and deposited onto a glass wafer and then bonded with another glass wafer. The channel depth is the same (250 nm) as the deposited silicon thickness. By using an advanced confocal laser scanning microscopy (CLSM) system, we directly visualized the pore level flow within micro/nano dual-scale channels with fluorescent-dyed water and oil phases. We found a serious fingering phenomenon when water displaced oil in the conduits even if water has higher viscosity and the residual oil was distributed as different forms in the matrices, micro-fractures and conduits. We demonstrated that different matrix/micro-fracture/macro-fracture geometries would cause different flow patterns that affect the oil recovery consequently. Taking advantage of such a micro/nano dual-scale 'shale-like' microfluidic model fabricated by a much simpler and lower-cost method, studies on complex fluid flow behavior within shale or other tight heterogeneous porous media would be significantly beneficial.

Developmental exposure to polychlorinated biphenyls (PCBs) in the maternal diet causes host-microbe defects in weanling offspring mice

The gut microbiota is important for maintaining homeostasis of the host. Gut microbes represent the initial site for toxicant processing following dietary exposures to environmental contaminants. The diet is the primary route of exposure to polychlorinated biphenyls (PCBs), which are absorbed via the gut, and subsequently interfere with neurodevelopment and behavior. Developmental exposures to PCBs have been linked to increased risk of neurodevelopmental disorders (NDD), including autism spectrum disorder (ASD), which are also associated with a high prevalence of gastrointestinal (GI) distress and intestinal dysbiosis. We hypothesized that developmental PCB exposure impacts colonization of the gut microbiota, resulting in GI pathophysiology, in a genetically susceptible host. Mouse dams expressing two heritable human mutations (double mutants [DM]) that result in abnormal Ca2+ dynamics and produce behavioral deficits (gain of function mutation in the ryanodine receptor 1 [T4826I-RYR1] and a human CGG repeat expansion [170-200 CGG repeats] in the fragile X mental retardation gene 1 [FMR1 premutation]). DM and congenic wild type (WT) controls were exposed to PCBs (0-6 mg/kg/d) in the diet starting 2 weeks before gestation and continuing through postnatal day 21 (P21). Intestinal physiology (Ussing chambers), inflammation (qPCR) and gut microbiome (16S sequencing) studies were performed in offspring mice (P28-P30). Developmental exposure to PCBs in the maternal diet caused significant mucosal barrier defects in ileum and colon (increased secretory state and tight junction permeability) of juvenile DM mice. Furthermore, PCB exposure increased the intestinal inflammatory profile (Il6, Il1β, and Il22), and resulted in dysbiosis of the gut microbiota, including altered β-diversity, in juvenile DM mice developmentally exposed to 1 mg/kg/d PCBs when compared to WT controls. Collectively, these findings demonstrate a novel interaction between PCB exposure and the gut microbiota in a genetically susceptible host that provide novel insight into environmental risk factors for neurodevelopmental disorders.

Binding and activity of sulfated metabolites of lower-chlorinated polychlorinated biphenyls towards thyroid hormone receptor alpha

There has been long-standing evidence that the lower-chlorinated polychlorinated biphenyls (LC-PCBs) can be metabolized to hydroxylated metabolites (OH-PCBs), which play important roles in the LC-PCBs induced toxicity. Recently, multiple studies have demonstrated the further metabolic transformation of OH-PCBs to LC-PCB sulfates in vitro and in vivo. Several studies found LC-PCB sulfates could bind with thyroid hormone (TH) transport proteins in the serum, indicating the potential relevance of these metabolites in the TH system disruption effects. However, the interaction of LC-PCB sulfates with the TH nuclear receptor (TR), another kind of important functional protein in the TH system, has not been explored. Here, by using a fluorescence competitive binding assay, we demonstrated that LC-PCB sulfates could bind with TRα. Moreover, the LC-PCB sulfates had higher binding potency than their corresponding OH-PCB precursors. By using a luciferase reporter gene assay, we found the LC-PCB sulfates showed agonistic activity towards the TRα signaling pathway. Molecular docking simulation showed all the tested LC-PCB sulfates could fit into the ligand binding pocket of the TRα. The LC-PCB sulfates formed hydrogen bond interaction with arginine 228 residue of TRα by their sulfate groups, which might facilitate the TR binding and agonistic activity. The present study suggests that interaction with the TR might be another possible mechanism by which LC-PCB sulfate induce TH system disruption effects.

PCBs in Older Buildings: Measuring PCB Levels in Caulk and Window Glazing Materials in Older Buildings

A method for the determination of polychlorinated biphenyls (PCBs) in caulk and glazing materials was developed and evaluated by application to a combination of 36 samples of caulk and glazing materials, from four schools in the northeastern area of the United States. Quality control analysis showed a range of 45 to 170% for spike recovery from the various samples and a range of 10.9 to 20.1% difference in precision among replicates. The result for the samples analyzed showed that three of the four schools sampled contained caulking and glazing materials with levels of PCBs >50 μg/g (range 54.6 μg/g to 445,000 μg/g). Across the four schools, 24% of collected caulk and glazing samples contained elevated PCB levels relative to the U.S. Environmental Protection Agency’s (EPA) bulk product waste criterion of 50 μg/g under “The Frank R. Lautenberg Chemical Safety for the 21st Century Act.” The PCBs determined in the samples, exhibited characteristic chromatographic patterns similar to those of Aroclors 1242, 1248, 1254, 1260, 1262, and a 1016/1254 mix.

The role of the gut microbiome in mediating neurotoxic outcomes to PCB exposure

A series of complex physiological processes underlie the development of the microbiota, gut, and brain in early life, which together communicate via the microbiota-gut-brain axis to maintain health and homeostasis. Disruption of these processes can lead to dysbiosis of the microbiota, pathophysiology of the gut and behavioral deficits including depression, anxiety and cognitive deficits. Environmental exposures, particularly in early life, can interfere with development and impact these pathways. This review will focus on the role of the microbiome and the gut in neurodevelopment and neurodegeneration as well as the impacts of environmental exposures, particularly to the neurotoxicant polychlorinated biphenyls (PCBs), given that the gut serves as the primary exposure route. There exists extensive research on the importance of the microbiome in the developing brain and connections with autism spectrum disorder (ASD) and increasing links being established between the microbiome and development of Alzheimer's disease (AD) in the elderly. Finally, we will speculate on the mechanisms through which PCBs can induce dysbiosis and dysregulate physiology of the gut and brain.

Resource quality of wood waste: The importance of physical and chemical impurities in wood waste for recycling

Recycling of post-consumer wood waste into particleboard may be hindered by the presence of physical and chemical impurities in the waste stream, therefore calling for increased attention on the quality of wood waste. However, wood waste comprises several uses/types of wood, along with different levels of contamination. This study provides the detailed sampling and characterisation of wood waste according to its source, type and resource quality grade. Eight tonnes of wood waste, intended for recycling and collected at three Danish recycling centres, were subdivided into 34 individual material fractions and characterised with respect to the presence of three classes of physical impurities (misplacements, interfering materials and low-quality wood waste) as well as chemical concentrations of more than hundred chemical elements and persistent organic pollutants (POPs). The results demonstrated that contaminant and concentration levels vary significantly according to wood waste type and source, thus emphasising that wood waste should not be viewed as a single material flow but rather be understood and managed according to the presence of individual fractions. Including only clean wood waste fractions at the three recycling centres, 41-87% of the collected wood waste per weight could be recycled - the rest being physical impurities. The results showed that chemical contamination was significantly higher for low-quality wood waste, thus clearly indicating that improvements in separate collection, sorting and handling of wood waste may improve the resource quality of wood waste and potentially achieve cleaner recycling practices.

3,3'-Dichlorobiphenyl (PCB 11) promotes dendritic arborization in primary rat cortical neurons via a CREB-dependent mechanism

PCB 11 (3,3'-dichlorobiphenyl), a contemporary congener produced as a byproduct of current pigment production processes, has recently emerged as a prevalent worldwide pollutant. We recently demonstrated that exposure to PCB 11 increases dendritic arborization in vitro, but the mechanism(s) mediating this effect remain unknown. To address this data gap, primary cortical neuron-glia co-cultures derived from neonatal Sprague-Dawley rats were exposed for 48 h to either vehicle (0.1% DMSO) or PCB 11 at concentrations ranging from 1 fM to 1 nM in the absence or presence of pharmacologic antagonists of established molecular targets of higher chlorinated PCBs. Reporter cell lines were used to test activity of PCB 11 at the aryl hydrocarbon receptor (AhR) and thyroid hormone receptor (THR). PCB 11 lacked activity at the AhR and THR, and antagonism of these receptors had no effect on the dendrite-promoting activity of PCB 11. Pharmacologic antagonism of various calcium channels or treatment with antioxidants also did not alter PCB 11-induced dendritic arborization. In contrast, pharmacologic blockade or shRNA knockdown of cAMP response element-binding protein (CREB) significantly decreased dendritic growth in PCB 11-exposed cultures, suggesting PCB 11 promotes dendritic growth via CREB-mediated mechanisms. Since CREB signaling is crucial for normal neurodevelopment, and perturbations of CREB signaling have been associated with neurodevelopmental disorders, our findings suggest that this contemporary pollutant poses a threat to the developing brain, particularly in individuals with heritable mutations that promote CREB signaling.

Revisiting the Contributions of Far- and Near-Field Routes to Aggregate Human Exposure to Polychlorinated Biphenyls (PCBs)

The general population is exposed to polychlorinated biphenyls (PCBs) by consuming food from far-field contaminated agricultural and aquatic environments, and inhalation and nondietary ingestion in near-field indoor or residential environments. Here, we seek to evaluate the relative importance of far- and near-field routes by simulating the time-variant aggregate exposure of Swedish females to PCB congeners from 1930 to 2030. We rely on a mechanistic model, which integrates a food-chain bioaccumulation module and a human toxicokinetic module with dynamic substance flow analysis and nested indoor-urban-rural environmental fate modeling. Confidence in the model is established by successfully reproducing the observed PCB concentrations in Swedish human milk between 1972 and 2016. In general, far-field routes contribute most to total PCB uptake. However, near-field exposure is notable for (i) children and teenagers, who have frequent hand-to-mouth contact, (ii) cohorts born in earlier years, e.g., in 1956, when indoor environments were severely contaminated, and (iii) lighter chlorinated congeners. The relative importance of far- and near-field exposure in a cross-section of individuals of different age sampled at the same time is shown to depend on the time of sampling. The transition from the dominance of near- to far-field exposure that has happened for PCBs may also occur for other chemicals used indoors.

Community reporting of ambient air polychlorinated biphenyl concentrations near a Superfund site

In this manuscript, we describe the process of establishing partnerships for community-based environmental exposure research, the tools and methods implemented for data report-back to community members, and the results of evaluations of these efforts. Data discovery and report-back materials developed by Statistics for Action (SFA) were employed as the framework to communicate the environmental data to community members and workshops. These data communication and research translation efforts are described in detail and evaluated for effectiveness based on feedback provided from community members who attended the workshops. Overall, the methods were mostly effective for the intended data communication.

In vitro profiling of toxic effects of prominent environmental lower-chlorinated PCB congeners linked with endocrine disruption and tumor promotion

The mechanisms contributing to toxic effects of airborne lower-chlorinated PCB congeners (LC-PCBs) remain poorly characterized. We evaluated in vitro toxicities of environmental LC-PCBs found in both indoor and outdoor air (PCB 4, 8, 11, 18, 28 and 31), and selected hydroxylated metabolites of PCB 8, 11 and 18, using reporter gene assays, as well as other functional cellular bioassays. We focused on processes linked with endocrine disruption, tumor promotion and/or regulation of transcription factors controlling metabolism of both endogenous compounds and xenobiotics. The tested LC-PCBs were found to be mostly efficient anti-androgenic (within nanomolar - micromolar range) and estrogenic (at micromolar concentrations) compounds, as well as inhibitors of gap junctional intercellular communication (GJIC) at micromolar concentrations. PCB 8, 28 and 31 were found to partially inhibit the aryl hydrocarbon receptor (AhR)-mediated activity. The tested LC-PCBs were also partial constitutive androstane receptor (CAR) and pregnane X receptor (PXR) agonists, with PCB 4, 8 and 18 being the most active compounds. They were inactive towards other nuclear receptors, such as vitamin D receptor, thyroid receptor α, glucocorticoid receptor or peroxisome proliferator-activated receptor γ. We found that only PCB 8 contributed to generation of oxidative stress, while all tested LC-PCBs induced arachidonic acid release (albeit without further modulations of arachidonic acid metabolism) in human lung epithelial cells. Importantly, estrogenic effects of hydroxylated (OH-PCB) metabolites of LC-PCBs (4-OH-PCB 8, 4-OH-PCB 11 and 4'-OH-PCB 18) were higher than those of the parent PCBs, while their other toxic effects were only slightly altered or suppressed. This suggested that metabolism may alter toxicity profiles of LC-PCBs in a receptor-specific manner. In summary, anti-androgenic and estrogenic activities, acute inhibition of GJIC and suppression of the AhR-mediated activity were found to be the most relevant modes of action of airborne LC-PCBs, although they partially affected also additional cellular targets.

Effects of room airflow on accurate determination of PUF-PAS sampling rates in the indoor environment

Accurate and precise interpretation of concentrations from polyurethane passive samplers (PUF-PAS) is important as more studies show elevated concentrations of PCBs and other semivolatile air toxics in indoor air of schools and homes. If sufficiently reliable, these samplers may be used to identify local sources and human health risks. Here we report indoor air sampling rates (Rs) for polychlorinated biphenyl congeners (PCBs) predicted for a frequently used double-dome and a half-dome PUF-PAS design. Both our experimentally calibrated (1.10 ± 0.23 m3 d-1) and modeled (1.08 ± 0.04 m3 d-1) Rs for the double-dome samplers compare well with literature reports for similar rooms. We determined that variability of wind speeds throughout the room significantly (P < 0.001) effected uptake rates. We examined this effect using computational fluid dynamics modeling and 3-D sonic anemometer measurements and found the airflow dynamics to have a significant but small impact on the precision of calculated airborne concentrations. The PUF-PAS concentration measurements were within 27% and 10% of the active sampling concentration measurements for the double-dome and half-dome designs, respectively. While the half-dome samplers produced more consistent concentration measurements, we find both designs to perform well indoors.

Emissions of Tetrachlorobiphenyls (PCBs 47, 51, and 68) from Polymer Resin on Kitchen Cabinets as a Non-Aroclor Source to Residential Air

Both Aroclor and non-Aroclor sources of airborne polychlorinated biphenyls (PCBs) were found in residential homes. We deployed passive air samplers at 16 residences and found PCB-47, PCB-51, and PCB-68 to account for up to 50% of measured indoor ΣPCBs (2700 pg m-3). Although PCB-47 and PCB-51 are neurotoxins present in Aroclor mixtures (<2.5 and <0.3 wt %, respectively), we found them at much higher levels than expected for any Aroclor source. PCB-68 is not present in Aroclor mixtures. Another non-Aroclor congener, PCB-11, a byproduct of pigment manufacturing, was found inside and outside of every household and was frequently the predominate congener. We conducted direct measurements of surface emissions and identified finished cabinetry to be a major source of PCB-47, PCB-51, and PCB-68. We hypothesize that these congeners are inadvertent byproducts of polymer sealant manufacturing and produced from the decomposition of 2,4-dichlorobenzoyl peroxide used as an initiator in free-radical polymerization of polyester resins. The presence of these three compounds in polymer products, such as silicone, has been widely noted, but to our knowledge they have never been shown to be a significant environmental source of PCBs.

Effects of exposure to polychlorinated biphenyls during different periods of development on ethanol consumption by male and female rats

In two experiments, male and female Sprague-Dawley rats were exposed to Polychlorinated Biphenyls (PCBs) to assess the effect PCBs, an estrogenic endocrine disrupting chemical (EEDC), would have on the voluntary consumption of alcohol. There are several EEDCs in our food that are known to increase estrogen in adolescent females. Our objective was to assess the effect that increasing estrogen, by adding the EEDC PCBs would have on volitional intake of alcohol. In Experiment 1, pregnant dams were exposed from gestational days 5-19 to a 1:1 mixture of Aroclor 1254/1260. In Experiment 2, lactating females were exposed to the same dose of 1254:1260 from postnatal days 1-21. In both experiments, a fade-in procedure was used to gradually introduce the rats to the taste of alcohol. At the end of the fade-in series all animals were given limited access (1 h/day) to a water/alcohol solution. We found that females exposed to PCBs, at two developmental periods, consumed significantly more alcohol than unexposed females and exposed and unexposed males. Results of the experiments are discussed in terms of how PCB exposure can disrupt endocrine processes (e.g., estrogenic endocrine disrupting chemicals, EEDC) that increase estrogen in females, thereby leading to increased alcohol consumption. Thus, the present findings suggest that EEDCs, such as PCBs, could contribute to the increase abuse of alcohol in adolescent females.

Hydroxylated and sulfated metabolites of commonly occurring airborne polychlorinated biphenyls inhibit human steroid sulfotransferases SULT1E1 and SULT2A1

Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants that are associated with varied adverse health effects. Lower chlorinated PCBs are prevalent in indoor and outdoor air and can be metabolized to their hydroxylated derivatives (OH-PCBs) followed by sulfation to form PCB sulfates. Sulfation is also a means of signal termination for steroid hormones. The human estrogen sulfotransferase (SULT1E1) and alcohol/hydroxysteroid sulfotransferase (SULT2A1) catalyze the formation of steroid sulfates that are inactive at steroid hormone receptors. We investigated the inhibition of SULT1E1 (IC50s ranging from 7.2 nM to greater than 10 μM) and SULT2A1 (IC50s from 1.3 μM to over 100 μM) by five lower-chlorinated OH-PCBs and their corresponding PCB sulfates relevant to airborne PCB-exposure. Several congeners of lower chlorinated OH-PCBs relevant to airborne PCB exposures were potent inhibitors of SULT1E1 and SULT2A1 and thus have the potential to disrupt regulation of intracellular concentrations of the receptor-active steroid substrates for these enzymes.

Partitioning of PCBs from air to clothing materials in a Danish apartment

Polychlorinated biphenyl (PCB) contamination of buildings continues to pose an exposure threat, even decades after their application in the form of calks and other building materials. In this research, we investigate the ability of clothing to sorb PCBs from contaminated air and thereby influence exposure. The equilibrium concentration of PCB-28 and PCB-52 was quantified for nine used clothing fabrics exposed for 56 days to air in a Danish apartment contaminated with PCBs. Fabric materials included pure materials such as cotton and polyester, or blends of polyester, cotton, viscose/rayon, and/or elastane. Air concentrations were fairly stable over the experimental period, with PCB-28 ranging from 350 to 430 ng/m³ and PCB-52 ranging from 460 to 550 ng/m³ . Mass accumulated in fabric ranged from below detection limits to 4.5 mg/g of fabric. Cotton or materials containing elastane sorbed more than polyester materials on a mass basis. Mass-normalized partition coefficients above detection limits ranged from 10^5.7 to 10^7.0  L/kg. Clothing acts as a reservoir for PCBs that extends dermal exposure, even when outside or in uncontaminated buildings.

Disparities in Environmental Exposures to Endocrine-Disrupting Chemicals and Diabetes Risk in Vulnerable Populations

Burgeoning epidemiological, animal, and cellular data link environmental endocrine-disrupting chemicals (EDCs) to metabolic dysfunction. Disproportionate exposure to diabetes-associated EDCs may be an underappreciated contributor to disparities in metabolic disease risk. The burden of diabetes is not uniformly borne by American society; rather, this disease disproportionately affects certain populations, including African Americans, Latinos, and low-income individuals. The purpose of this study was to review the evidence linking unequal exposures to EDCs with racial, ethnic, and socioeconomic diabetes disparities in the U.S.; discuss social forces promoting these disparities; and explore potential interventions. Articles examining the links between chemical exposures and metabolic disease were extracted from the U.S. National Library of Medicine for the period of 1966 to 3 December 2016. EDCs associated with diabetes in the literature were then searched for evidence of racial, ethnic, and socioeconomic exposure disparities. Among Latinos, African Americans, and low-income individuals, numerous studies have reported significantly higher exposures to diabetogenic EDCs, including polychlorinated biphenyls, organochlorine pesticides, multiple chemical constituents of air pollution, bisphenol A, and phthalates. This review reveals that unequal exposure to EDCs may be a novel contributor to diabetes disparities. Efforts to reduce the individual and societal burden of diabetes should include educating clinicians on environmental exposures that may increase disease risk, strategies to reduce those exposures, and social policies to address environmental inequality as a novel source of diabetes disparities.

Species and Sex Differences in the Morphogenic Response of Primary Rodent Neurons to 3,3'-Dichlorobiphenyl (PCB 11)

PCB 11 is an emerging global pollutant that we recently showed promotes axonal and dendritic growth in primary rat neuronal cell cultures. Here, we address the influence of sex and species on neuronal responses to PCB 11. Neuronal morphology was quantified in sex-specific primary hippocampal and cortical neuron-glia co-cultures derived from neonatal C57BL/6J mice and Sprague Dawley rats exposed for 48 h to vehicle (0.1% DMSO) or PCB 11 at concentrations ranging from 1 fM to 1 nM. Total axonal length was quantified in tau-1 immunoreactive neurons at day in vitro (DIV) 2; dendritic arborization was assessed by Sholl analysis at DIV 9 in neurons transfected with MAP2B-FusRed. In mouse cultures, PCB 11 enhanced dendritic arborization in female, but not male, hippocampal neurons and male, but not female, cortical neurons. In rat cultures, PCB 11 promoted dendritic arborization in male and female hippocampal and cortical neurons. PCB 11 also increased axonal growth in mouse and rat neurons of both sexes and neuronal cell types. These data demonstrate that PCB 11 exerts sex-specific effects on neuronal morphogenesis that vary depending on species, neurite type, and neuronal cell type. These findings have significant implications for risk assessment of this emerging developmental neurotoxicant.

Polychlorinated biphenyl and polybrominated diphenyl ether profiles in serum from cattle, sheep, and goats across California

It has been previously been shown by our lab and others that persistent organic pollutants, such as polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), are contaminants in milk produced for human consumption. To further this research we determined the concentration of 21 PCB and 14 PBDE congeners in livestock serum, mainly bovine, across California. Congeners were extracted from serum using solid phase extraction (SPE), cleaned up by silica cartridge and quantified using gas chromatography-triple quadruple mass spectrometry. We detected significant differences among species and the production class of cattle (beef or dairy). The sum of all 21 PCB congeners (ΣPCBs) in caprine and ovine sera had a mean value of 9.26 and 9.13 ng/mL, respectively, compared to 3.98 ng/mL in bovine sera. The mean value for the sum of all 14 PBDE congeners (ΣPBDEs) in caprine and ovine sera was 2.82 and 2.39 ng/mL, respectively, compared to 0.91 ng/mL in bovine sera. Mean ΣPCBs in dairy cattle was 5.92 ng/mL compared to 2.70 ng/mL in beef cattle. Mean ΣPBDEs in dairy cattle was 1.33 ng/mL compared to 0.70 ng/mL in beef cattle. There were no regional differences in the ΣPCBs or ΣPBDEs in cattle distributed across California. These results highlight the fact that livestock are still being exposed to these pollutants yet little is known about where this exposure may be coming from.

The Relationship between the Blood Level of Persistent Organic Pollutants and Common Gastrointestinal Symptoms

Background

Persistent organic pollutants (POPs) are toxic materials that cannot be broken down naturally and that easily accumulate in the body. Although several studies have attempted to uncover the effects of POPs on the endocrine and nervous systems and on cancer, few focus on the relationship between low-dose POPs and public health. Here, we attempt to determine the relationship between the level of POPs and common gastrointestinal symptoms, including abdominal discomfort, diarrhea, and constipation.

Methods

We recruited 121 subjects who visited Kyungpook National University Medical Center for health screening. Plasma concentrations were evaluated for 40 kinds of POPs including 17 types of polychlorinated biphenyls (PCBs) and 23 types of organochlorine pesticides (OCP). Furthermore, the Korean version of the Rome III criteria was used to identify gastrointestinal symptoms.

Results

Based on our results, abdominal discomfort showed an inverse relationship with several PCBs and an inverted U-shaped relationship with several other OCPs including pp-DDD and pp-DDT. The effects of pp-DDD and pp-DDT on abdominal discomfort were similar to those of OCPs on obesity and metabolic syndrome.

Conclusion

Our results suggest that mild and unspecified gastrointestinal symptoms with no clear causes could be related to POP levels.

Airborne PCBs and OH-PCBs Inside and Outside Urban and Rural U.S. Schools

PCBs appear in school air because many school buildings were built when PCBs were still intentionally added to building materials and because PCBs are also present through inadvertent production in modern pigment. This is of concern because children are especially vulnerable to the toxic effects of PCBs. Here we report indoor and outdoor air concentrations of PCBs and OH-PCBs from two rural schools and four urban schools, the latter near a PCB-contaminated waterway of Lake Michigan in the United States. Samples (n = 108) were collected as in/out pairs using polyurethane foam passive air samplers (PUF-PAS) from January 2012 to November 2015. Samples were analyzed using GC/MS-MS for all 209 PCBs and 72 OH-PCBs. Concentrations inside schools were 1-2 orders of magnitude higher than outdoors and ranged from 0.5 to 194 ng/m³ (PCBs) and from 4 to 665 pg/m³ (OH-PCBs). Congener profiles were similar within each sampling location across season but different between schools and indicated the sources as Aroclors from building materials and individual PCBs associated with modern pigment. This study is the first cohort-specific analysis to show that some children's PCB inhalation exposure may be equal to or higher than their exposure through diet.

Source Apportionment of Atmospheric Polychlorinated Biphenyls in New Jersey 1997-2011

Concentrations of polychlorinated biphenyls (PCBs) in the Delaware River currently exceed the Water Quality Criteria of 16 pg/L for the sum of PCBs due in part to atmospheric deposition. The purpose of this work was to use a source apportionment tool called Positive Matrix Factorization (PMF) to identify the sources of PCBs to the atmosphere in this area and determine whether their concentrations are declining over time. The data set was compiled by the Delaware Atmospheric Deposition Network (DADN) from samples taken in Camden, NJ from 1999 to 2011 and New Brunswick, NJ from 1997 to 2011. The PMF analysis revealed four resolved factors at each site. The factors that dominate the PCB burden in the atmosphere at both Camden and New Brunswick resemble Aroclor 1242. These factors declined in concentration during some portions of the monitoring period, but this decline slowed or stopped during 2003-2011. None of the factors displayed consistent declines in concentration throughout the monitoring periods, and some factors actually increased in concentration during some periods. This suggests natural attenuation alone will not control atmospheric PCB concentrations, and additional efforts are needed to control PCB atmospheric emissions as well as the numerous other sources of PCBs to the estuary.

Identification of a sulfate metabolite of PCB 11 in human serum

Despite increasing evidence for a major role for sulfation in the metabolism of lower-chlorinated polychlorinated biphenyls in vitro and in vivo, and initial evidence for potential bioactivities of the resulting sulfate ester metabolites, the formation of PCB sulfates in PCB exposed human populations had not been explored. The primary goal of this study was to determine if PCB sulfates, and potentially other conjugated PCB derivatives, are relevant classes of PCB metabolites in the serum of humans with known exposures to PCBs. In order to detect and quantify dichlorinated PCB sulfates in serum samples of 46 PCB-exposed individuals from either rural or urban communities, we developed a high-resolution mass spectrometry-based protocol using 4-PCB 11 sulfate as a model compound. The method also allowed the preliminary analysis of these 46 human serum extracts for the presence of other metabolites, such as glucuronic acid conjugates and hydroxylated PCBs. Sulfate ester metabolites derived from dichlorinated PCBs were detectable and quantifiable in more than 20% of analyzed serum samples. Moreover, we were able to utilize this method to detect PCB glucuronides and hydroxylated PCBs, albeit at lower frequencies than PCB sulfates. Altogether, our results provide initial evidence for the presence of PCB sulfates in human serum. Considering the inability of previously employed analytical protocols for PCBs to extract these sulfate ester metabolites and the concentrations of these metabolites observed in our current study, our data support the hypothesis that total serum levels of PCB metabolites in exposed individuals may have been underestimated in the past.

Organohalogenated contaminants in type 2 diabetic serum from Jeddah, Saudi Arabia

Most of the organohalogenated contaminants (OHCs) have high environmental stability and are lipophilic in nature, thus bioaccumulate through the various routes e.g., inhalation, dermal contact and food intake. Human exposure to these OHCs can induce adverse health effects. Studies on the occurrence of OHCs in human samples from Saudi Arabia are scarce. Therefore, this study aimed at providing preliminary insight on the occurrence of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated biphenyl ethers (PBDEs) in diabetic and non-diabetic donors from KSA. Serum samples were collected from type 2 diabetic patients (n = 40) and control donors (n = 20) to study the impact of OHCs on their health. For the first time we studied the difference of ƩOHCs in type 2 diabetic and control participants. The order of obtained results was ƩOCPs (35-650 ng/g lw)> ƩPCBs (15-90 ng/g lw)> ƩPBDEs (1.5-68 ng/g lw). The major contributors were p,p'-DDE (median 44 ng/g lw), PCB 153 (2.3 ng/g lw), PCB 138 (2.1 ng/g lw), BDE 153 (1.2 ng/g lw) and BDE 47 (0.85 ng/g lw). Exposure to different OHCs between male and female donors was not significantly different (p > 0.05). However, ƩPCBs and ƩOHCs were significantly higher (p < 0.05) in diabetic donors than those of control group. We computed significantly positive correlations (p < 0.05) among different OHCs and between OHCs and age factor. The current study highlights the presence of different OHCs in humans from Jeddah, KSA. This is a preliminary study based on small sample size but our results suggested that detailed studies are required to understand the sources of these pollutants and their impact on human health.

Health Effects of PCBs in Residences and Schools (HESPERUS): PCB - health Cohort Profile

Polychlorinated-biphenyls (PCBs) were introduced in the late 1920s and used until the 1970s when they were banned in most countries due to evidence of environmental build-up and possible adverse health effects. However they still persist in the environment, indoors and in humans. Indoor air in contaminated buildings may confer airborne exposure markedly above background regional PCB levels. To date, no epidemiological studies have assessed the health effects from exposure to semi-volatile PCBs in the indoor environment. Indoor air PCBs are generally less chlorinated than PCBs that are absorbed via the diet, or via past occupational exposure; therefore their health effects require separate risk assessment. Two separate cohorts of individuals who have either attended schools (n = 66,769; 26% exposed) or lived in apartment buildings (n = 37,185; 19% exposed), where indoor air PCB concentrations have been measured were created. An individual estimate of long-term airborne PCB exposure was assigned based on measurements. The cohorts will be linked to eight different national data sources on mortality, school records, residential history, socioeconomic status, and chronic disease and reproductive outcomes. The linking of indoor air exposures with health outcomes provides a dataset unprecedented worldwide. We describe a project, called HESPERUS (Health Effects of PCBs in Residences and Schools), which will be the first study of the long term health effects of the lower-chlorinated, semi-volatile PCBs in the indoor environment.

Laboratory study of PCB transport from primary sources to settled dust

Dust is an important sink for indoor air pollutants, such as polychlorinated biphenyls (PCBs) that were used in building materials and products. In this study, two types of dust, house dust and Arizona Test Dust, were tested in a 30-m(3) stainless steel chamber with two types of panels. The PCB-containing panels were aluminum sheets coated with a PCB-spiked primer or caulk. The PCB-free panels were coated with the same materials but without PCBs. The dust evenly spread on each panel was collected at different times to determine its PCB content. The data from the PCB panels were used to evaluate the PCB migration from the source to the dust through direct contact, and the data from the PCB-free panels were used to evaluate the sorption of PCBs through the dust/air partition. Settled dust can adsorb PCBs from air. The sorption concentration was dependent on the congener concentration in the air and favored less volatile congeners. When the house dust was in direct contact with the PCB-containing panel, PCBs migrated into the dust at a much faster rate than the PCB transfer rate due to the dust/air partition. The dust/source partition was not significantly affected by the congener's volatility. For a given congener, the ratio between its concentration in the dust and in the source was used to estimate the dust/source partition coefficient. The estimated values ranged from 0.04 to 0.16. These values are indicative of the sink strength of the tested house dust being in the middle or lower-middle range.

Polybrominated diphenyl ethers and polychlorinated biphenyls in dust from cars, homes, and offices in Lagos, Nigeria

Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) were measured in dust from 16 cars, 12 homes, and 18 offices in Lagos, Nigeria. These represent the first and second reports respectively of contamination of Nigerian indoor dust with these contaminants, and the second report on PCBs in car dust worldwide. Concentrations of BDE-47 and BDE-99 in two car dust samples (9300 and 3700 ng g(-1) for BDE-47 and 4200 and 19,000 ng g(-1) for BDE-99), are amongst the highest ever reported in car dust. ANOVA comparison with Canada, New Zealand, the UK, and the USA; reveals concentrations of BDEs-28, 49, 47, 66, 100, 99, 154, and 153 in Nigerian house dust, to be significantly lower than in Canada and the USA, with those of BDE-49 and 154 significantly lower than in New Zealand and the UK. Concentrations of BDE-209 in Nigeria were significantly lower than concentrations in the UK and the USA; while concentrations of PCB-180 were significantly greater than those in New Zealand, the UK, and the USA. Median concentrations of PCBs in cars were substantially higher than in the only previous study (in Kuwait and Pakistan). While median concentrations of PBDEs in cars generally exceeded those in homes, this was significant only for BDEs-49, 154, and 197, with concentrations in cars significantly greater than those in offices for BDEs-49 and 154. Contrastingly, concentrations of all target PCBs in offices exceeded significantly those in cars. This study underlines the truly global distribution of indoor contamination with PBDEs and PCBs.