A Critical Review about Human Exposure to Polychlorinated Dibenzo-p-Dioxins (PCDDs), Polychlorinated Dibenzofurans (PCDFs) and Polychlorinated Biphenyls (PCBs) through Foods

Efficient biostimulation of microbial dechlorination of polychlorinated biphenyls by acetate and lactate under nitrate reducing conditions: Insights into dechlorination pathways and functional genes

Microbial-catalyzed reductive dechlorination of polychlorinated biphenyls (PCBs) is largely affected by the indigenous sediment geochemical properties. In this study, the effects of nitrate on PCB dechlorination and microbial community structures were first investigated in Taihu Lake sediment microcosms. And biostimulation study was attempted supplementing acetate/lactate. PCB dechlorination was apparently inhibited under nitrate-reducing conditions. Lower PCB dechlorination rate and less PCB dechlorination extent were observed in nitrate amended sediment microcosms (T-N) than those in non-nitrate amended microcosms (T-1) during 66 weeks of incubation. The total PCB mass reduction in T-N was 17.6% lower than that in T-1. The flanked-para dechlorination was completely inhibited, while the ortho-flanked meta dechlorination was only partially inhibited in T-N. The 7.5 mM of acetate/lactate supplementation recovered PCB dechlorination by resuming ortho-flanked meta dechlorination. Repeated additions of lactate showed more effective biostimulation than acetate. Phylum Chloroflexi, containing most known PCB dechlorinators, was found to play a vital role on stability of the network structures. In T-N, putative dechlorinating Chloroflexi, Dehalococcoides and RDase genes rdh12, pcbA4, pcbA5 all declined. With acetate/lactate supplementation, Dehalococcoides grew by 1-2 orders of magnitude and rdh12, pcbA4, pcbA5 increased by 1-3 orders of magnitude. At Week 66, parent PCBs declined by 86.4% and 80.9% respectively in T-N-LA and T-N-AC compared to 69.9% in T-N. These findings provide insights into acetate/lactate biostimulation as a cost-effective approach for treating PCB contaminated sediments undergoing nitrate inhibition.

Identification of estrogen receptor agonists among hydroxylated polychlorinated biphenyls using classification-based quantitative structure-activity relationship models

Identification of estrogen receptor (ER) agonists among environmental toxicants is essential for assessing the potential impact of toxicants on human health. Using 2D autocorrelation descriptors as predictor variables, two binary logistic regression models were developed to identify active ER agonists among hydroxylated polychlorinated biphenyls (OH-PCBs). The classifications made by the two models on the training set compounds resulted in accuracy, sensitivity and specificity of 95.9 %, 93.9 % and 97.6 % for ERα dataset and 91.9 %, 90.9 % and 92.7 % for ERβ dataset. The areas under the ROC curves, constructed with the training set data, were found to be 0.985 and 0.987 for the two models. Predictions made by models I and II correctly classified 84.0 % and 88.0 % of the test set compounds and 89.8 % and 85.8% of the cross-validation set compounds respectively. The two classification-based QSAR models proposed in this paper are considered robust and reliable for rapid identification of ERα and ERβ agonists among OH-PCB congeners.

Polychlorinated biphenyl (PCB) half-lives in humans: A systematic review

This manuscript presents a systematic review of PCB half-lives reported in the scientific literature. The review was completed in accordance with PRISMA guidelines and included a review of almost 1000 peer-reviewed publications. In total, 26 articles were found to report half-lives in humans, with the majority of data coming from studies performed in North America on individuals suspected to have been exposed to PCBs. Terminology for reporting PCB half-lives was inconsistent, so we have attempted to consolidate this and recommend using either "apparent half-life" or "intrinsic half-life" in future studies. Within the literature, values for reported half-lives varied considerably for different PCBs. Less chlorinated PCBs generally have shorter half-lives than more chlorinated PCBs. It was interesting to note the large variability of half-lives reported for the same PCB. For example, the reported half-life for PCB 180 varied by nearly 3 orders of magnitude (0.34 years-300 years). Our review identified that the half-lives estimated were largely dependent on the studied cohort. We discuss the importance of PCB body burden, degree of chlorination and PCB structure, gender, age, breastfeeding, BMI, and smoking status on half-life estimations. We also identified significantly shorter half-lives for some PCBs in occupationally exposed individuals compared to results reported from the general population. PCB half-lives are not the same for every PCB or every individual. Therefore, careful consideration is needed when these values are used in human exposure studies.

Resveratrol ameliorates ortho- polychlorinated biphenyls' induced toxicity in ovary cells

Polychlorinated biphenyls (PCBs) can induce chronic oxidative stress, inflammation, and cell death, leading to coronary heart disease, endothelial dysfunction, neurotoxicity, cancer, obesity, type 2 diabetes, reproductive dysfunction, etc. The aim of this study was to investigate possible protective effect of resveratrol (2.5-20 μM) in ovarian cells exposed to PCBs. An emphasis was on identifying mechanisms of resveratrol action upon distinct structure of the individual PCB congener-planar dioxin-like PCB 77 and non-planar di-ortho-substituted PCB 153. Multiple toxicity endpoint analysis was performed. Cell viability/proliferation was assessed by Trypan Blue exclusion method, Neutral Red, Kenacid Blue, and MTT bioassays. The level of oxidative stress was measured by fluorescent probes, and flow cytometry was applied to evaluate the mode of cell death. Resveratrol applied alone did not affect cell proliferation and viability in doses up to 20 µM, although significant antioxidative activity was observed. Toxic effects of ortho-PCB 153 (cytotoxicity, oxidative stress, and cell death) were mitigated by resveratrol. On the contrary pre-incubation with resveratrol did not result in cell viability protection when planar PCB 77 was applied. This indicates that resveratrol efficacy may be linked to specific structure of the individual congener, suggesting nutritional modulation of environmental insults caused by ortho-PCBs. We point out the importance of resveratrol dosage considering that synergistic cytotoxic effect with both PCB congeners is observed at concentrations ≥ 10 μM.

Methoxylated Modification of Glutathione-Mediated Metabolism of Halobenzoquinones In Vivo and In Vitro

Xenobiotics were generally detoxified in organisms through interaction with endogenous molecules, which may also generate metabolites of increased toxicity. Halobenzoquinones (HBQs), a group of highly toxic emerging disinfection byproducts (DBPs), can be metabolized by reacting with glutathione (GSH) to form various glutathionylated conjugates (SG-HBQs). In this study, the cytotoxicity of HBQs in CHO-K1 cells showed a wavy curve as a function of increased GSH dosage, which was inconsistent with the commonly recognized progressive detoxification curve. We hypothesized that the formation and cytotoxicity of GSH-mediated HBQ metabolites contribute to the unusual wave-shaped cytotoxicity curve. Results showed that glutathionyl-methoxyl HBQs (SG-MeO-HBQs) were identified to be the primary metabolites significantly correlated with the unusual cytotoxicity variation of HBQs. The formation pathway was initiated by stepwise metabolism via hydroxylation and glutathionylation to produce detoxified hydroxyl HBQs (OH-HBQs) and SG-HBQs, followed by methylation to generate SG-MeO-HBQs of potentiated toxicity. To further verify the occurrence of the aforementioned metabolism in vivo, SG-HBQs and SG-MeO-HBQs were detected in the liver, kidney, spleen, testis, bladder, and feces of HBQ-exposed mice, with the highest concentration quantified in the liver. The present study supported that the co-occurrence of metabolism can be antagonistic, which enhanced our understanding of the toxicity and metabolic mechanism of HBQs.

Adverse health effects of emerging contaminants on inflammatory bowel disease

Inflammatory bowel disease (IBD) is becoming increasingly prevalent with the improvement of people's living standards in recent years, especially in urban areas. The emerging environmental contaminant is a newly-proposed concept in the progress of industrialization and modernization, referring to synthetic chemicals that were not noticed or researched before, which may lead to many chronic diseases, including IBD. The emerging contaminants mainly include microplastics, endocrine-disrupting chemicals, chemical herbicides, heavy metals, and persisting organic pollutants. In this review, we summarize the adverse health effect of these emerging contaminants on humans and their relationships with IBD. Therefore, we can better understand the impact of these new emerging contaminants on IBD, minimize their exposures, and lower the future incidence of IBD.

Serum levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in a sample of Lebanese pregnant women: The role of dietary, anthropometric, and environmental factors

Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are unintentionally produced, toxic environmental chemicals that persist for long years and bioaccumulate along the food chain, contaminating humans through diet. A particularly critical population subgroup is pregnant women given the adverse health effects on fetuses and newborns. Several anthropogenic sources of exposure to PCDD/Fs exist in Lebanon. Therefore, the aim of the present cross-sectional study is to measure the levels of PCDD/Fs in a sample of pregnant women in Lebanon and to explore potential associated factors. In this study, we measured serum concentrations of seven dioxins and ten furans, among 423 pregnant women recruited at delivery, using gas chromatography MS/MS. Among 269 participants, maternal sociodemographic information was collected including vicinity to landfills, incineration, pesticide use, industrial activity, and smoking. Anthropometric data were registered regarding pre-pregnancy body mass index (BMI), pre-pregnancy weight loss from restrictive diet, and gestational weight gain. Intake of major food groups generally related to PCDD/Fs was reported (fish, red meat, poultry, and dairy). Bivariate and multivariate analyses were performed to identify associations. PCDD/Fs were detected in 0 to 56.1% of the sample. Geometric mean concentrations were 75.5 (2.35) pg/g lipid and 2.25 (1.39) TEQ₂₀₀₅ pg/g lipid for total dioxins, and 2.66 (1.76) pg/g lipid and 0.34 (1.78) TEQ₂₀₀₅ pg/g lipid for total furans. Levels were relatively lower than levels previously observed in France, Germany, Mexico, Ghana, and Japan. Red meat consumption was the most consistently associated factor with a 2.38-2.57 fold increase in PCDD/F levels. Pre-pregnancy weight loss showed inverse associations with PCDD/F congeners. Vicinity to illegal incineration was also associated with a 2.32-2.43 fold increase in PCDD/F levels. In conclusion, results showed the importance of dietary, anthropometric, and environmental factors in the present sample's exposure to PCDD/Fs, in a region that contains anthropogenic sources of contamination.

The Relationship between Typical Environmental Endocrine Disruptors and Kidney Disease

Endocrine disrupting chemicals (EDCs) are exogenous substances that alter the endocrine function of an organism, to result in adverse effects on growth and development, metabolism, and reproductive function. The kidney is one of the most important organs in the urinary system and an accumulation point. Studies have shown that EDCs can cause proteinuria, affect glomeruli and renal tubules, and even lead to diabetes and renal fibrosis in animal and human studies. In this review, we discuss renal accumulation of select EDCs such as dioxins, per- and polyfluoroalkyl substances (PFAS), bisphenol A (BPA), and phthalates, and delineate how exposures to such EDCs cause renal lesions and diseases, including cancer. The regulation of typical EDCs with specific target genes and the activation of related pathways are summarized.

Endocrine disrupting chemicals impact on ovarian aging: Evidence from epidemiological and experimental evidence

Endocrine-disrupting chemicals (EDCs) are ubiquitous in daily life, but their harmful effects on the human body have not been fully explored. Recent studies have shown that EDCs exposure could lead to infertility, menstrual disorder and menopause, resulting in subsequent effects on female health. Therefore, it is of great significance to clarify and summarize the impacts of EDCs on ovarian aging for explaining the etiology of ovarian aging and maintaining female reproductive health. Here in this review, we focused on the impacts of ten typical environmental contaminants on the progression of ovarian aging during adult exposure, including epidemiological data in humans and experimental models in rodents, with their clinical phenotypes and underlying mechanisms. We found that both persistent (polychlorinated biphenyls, perfluoroalkyl and polyfluoroalkyl substances) and non-persistent (phthalates) EDCs exposure could increase an overall risk of ovarian aging, leading to the diminish of ovarian reserve, decline of fertility or fecundity, irregularity of the menstrual cycle and an earlier age at menopause, and/or premature ovarian insufficiency/failure in epidemiological studies. Among these, the loss of follicles can also be validated in experimental studies of some EDCs, such as BPA, phthalates, parabens and PCBs. The underlying mechanisms may involve the impaired ovarian follicular development by altering receptor-mediated pro-apoptotic pathways, inducing signal transduction and cell cycle arrest and epigenetic modification. However, there were inconsistent results in the impacts on fertility/fecundity, menstrual/estrous cycle and hormone changes response to different EDCs, and differences between human and animal studies. Our review summarizes the current state of knowledge on ovarian disrupters, highlights their risks to ovarian aging and identifies knowledge gaps in humans and animals. We therefore propose that females adopt healthy lifestyle changes to minimize their exposure to both persistent and non-persistent chemicals, that have the potential damage to their reproductive function.

Exposure to the Dioxin-like Pollutant PCB 126 Afflicts Coronary Endothelial Cells via Increasing 4-Hydroxy-2 Nonenal: A Role for Aldehyde Dehydrogenase 2

Exposure to environmental pollutants, including dioxin-like polychlorinated biphenyls (PCBs), play an important role in vascular inflammation and cardiometabolic diseases (CMDs) by inducing oxidative stress. Earlier, we demonstrated that oxidative stress-mediated lipid peroxidation derived 4-hydroxy-2-nonenal (4HNE) contributes to CMDs by decreasing the angiogenesis of coronary endothelial cells (CECs). By detoxifying 4HNE, aldehyde dehydrogenase 2 (ALDH2), a mitochondrial enzyme, enhances CEC angiogenesis. Therefore, we hypothesize that ALDH2 activation attenuates a PCB 126-mediated 4HNE-induced decrease in CEC angiogenesis. To test our hypothesis, we treated cultured mouse CECs with 4.4 µM PCB 126 and performed spheroid and aortic ring sprouting assays, the ALDH2 activity assay, and Western blotting for the 4HNE adduct levels and real-time qPCR to determine the expression levels of Cyp1b1 and oxidative stress-related genes. PCB 126 increased the gene expression and 4HNE adduct levels, whereas it decreased the ALDH2 activity and angiogenesis significantly in MCECs. However, pretreatment with 2.5 µM disulfiram (DSF), an ALDH2 inhibitor, or 10 µM Alda 1, an ALDH2 activator, before the PCB 126 challenge exacerbated and rescued the PCB 126-mediated decrease in coronary angiogenesis by modulating the 4HNE adduct levels respectively. Finally, we conclude that ALDH2 can be a therapeutic target to alleviate environmental pollutant-induced CMDs.

Insights into the toxicokinetic, tissue distribution and maternal transfer of polychlorinated dibenzo-p-dioxins/dibenzofurans in laying hens fed with dioxin-associated dietary

A controlled feeding experiment was conducted to investigate the toxicokinetic of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) in laying hens. The laying hens were fed with fly ash contaminated diets to replicate the typical environment-feed-chicken transfer chain in China. Levels of PCDD/Fs rapidly increased in the pectoralis, adipose tissue, liver and blood of laying hens with daily ingestion of dioxin-associated diets during the 14-days exposure period, and then a gradual decrease was observed in the 28-days depletion period. The depletion rates (k_d) of the toxic equivalent of PCDD/Fs (TEQ_PCDD/Fs) were 0.043, 0.031 and 0.030 day^-1 for pectoralis, liver and adipose tissue in the high-exposure group, respectively. The k_d of individual PCDD/Fs in liver increased with the numbers of chlorine and n-octanol/water partition coefficient (logK_OW), indicating that lower chlorinated congeners had higher half-lives in liver. Decreasing ratios of liver to adipose tissue for PCDD/Fs (L/AT) throughout the experiment suggested a tendency of equilibrium partitioning between liver and adipose tissue. Congener-specific sequestration of PCDD/Fs in liver was revealed by the positive correlation between L/AT ratios and logK_OW. Physiological bioconcentration factors of PCDD/Fs were estimated at the end of exposure, indicating the preferential accumulation of hexachlorinated congeners in most tissues. Furthermore, maternal transfer of PCDD/Fs was positively correlated with logK_OW, implying that more lipophilic congeners were transferred to egg along with the lipid circulation.

Maternal Exposure to Polychlorinated Biphenyls and Asthma, Allergic Rhinitis and Atopic Dermatitis in the Offspring: The Environmental Health Fund Birth Cohort

Background: Polychlorinated biphenyls (PCBs) are persistent organic pollutants banned for use worldwide. Due to their biodegradation resistance, they accumulate along the food chain and in the environment. Maternal exposure to PCBs may affect the fetus and the infant. PCBs are immunotoxic and may damage the developing immune system. PCBs are associated with elevated IgE antibodies in cord blood and are considered to be predictive of atopic reactions. Several studies on the association between prenatal exposure to PCBs and atopic reactions were previously published, albeit with conflicting results.

Objectives: To examine the association between maternal PCBs levels and atopic reactions in their offspring.

Methods: During the years 2013–2015, a prospective birth cohort was recruited at the delivery rooms of Shamir Medical Center (Assaf Harofeh) and “Dana Dwek” Children’s Hospital. Four PCBs congeners were investigated: PCBs 118, 138, 153, and 180. In 2019, when children reached the age of 4–6 years, mothers were interviewed using the ISAAC questionnaire to assess symptoms of atopic reactions, including asthma, allergic rhinitis, and atopic dermatitis.

Results: One hundred and fifty mother-child dyads were analyzed. No significant differences were found in the median serum PCBs concentrations of each studied congener or total PCBs for asthma, allergic rhinitis, atopic dermatitis diagnosis, or parent-reported symptoms. No association was found between exposure to total PCBs and the risk for asthma symptoms or diagnosis, adjusted to maternal age and family member with atopic condition: aOR = 0.94, 95%CI: (0.88; 0.99). No association was observed between each studied PCB congener and asthma symptoms or diagnosis. The same results were found also for other studied outcomes—allergic rhinitis and atopic dermatitis.

Conclusion: Our study joins a series of previous studies that attempt to shed light on environmental exposures in utero as influencing factors for atopic conditions in children. Our results reflect the complexity of the pathophysiology of these phenomena. No relationship between maternal serum PCBs levels was demonstrated for asthma, allergic rhinitis, or atopic dermatitis. However, additional multi-participant studies, with longer, spanning into later pediatric age follow up are needed.

The footprint of dioxins in globally traded pork meat

The bioaccumulation of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), known as dioxins, in fatty meat is one of primary pathways of entry into the human body, but levels of human exposure to dioxins in fatty meat subject to global trade are unknown. We show high dioxin estimated dietary intake (EDI) via pork consumption in Europe, the United States, and China, owing to stronger dioxin environmental contamination and high pork consumption in these countries. The dioxin risk transfer embodied in pork trade is mostly significant in high-latitude countries and regions of Canada, Russia, and Greenland because these regions with low dioxin environmental levels import large amounts of pork meat from more severely dioxin-contaminated Europe and the United States. We demonstrate that global pig feed trading decreases the exposure of pork consumers to dioxins via the import of feed from countries with low dioxin environmental contamination by pig breeding countries.

Occurrence and spatial distribution of dioxin and dioxin-like compounds in topsoil of Taranto (Apulia, Italy) by GC-MS analysis and DR-CALUX® bioassay

The aim of the present study was to assess the occurrence and spatial distribution of PCDD/Fs and dioxin-like compounds in topsoils of Taranto (Apulia Region), one of the most heavily industrialized and contaminated area of Southern Italy. A combined approach of chemical analysis by GC-MS/MS and AhR reporter gene bioassay was applied in a subset of topsoil samples (n = 20) collected in 2017-18 from ten sites embracing three levels of risk (from high to low) in the framework of a large survey inside Taranto municipality. TCDD-BEQs and GC-MS/MS TEQ_WHO and TEQ_THEORETICAL revealed a decreasing trend with the distance from main industrial settings and landfill areas. A strong correlation between TCDD-BEQs and TEQ_WHO values (R² = 0.85) and TEQ_THEORETICAL (R² = 0.88) was also found. In 3 out of 10 topsoil investigated, BEQs and TEQ_{WHO/THEORETICAL} resulted above Italian National Regulatory Limits for ∑PCDD/Fs in green, private and recreational used soils (10 ng TEQ/kg d.w. D.Lgs 152/2006) and for ∑PCDD/F/dl-PCBs in agricultural and farming soil (6 ng TEQ/kg d.w. D.M. 46/2019). GC-MS/MS pattern revealed the highest prevalence of dl-PCBs in 6 out of 10 sites, followed by PCDFs and PCDDs. Those sites are all located in proximity of main industrial steel and iron ore sinter plant, steel plant's landfills and illegal dumping sites. An update on occurrence and spatial distribution of PCDD/Fs and dl-PCBs contamination of Taranto urban soils was obtained and the DR-CALUX® bioassay was further recommended as a suitable screening tool for environmental and human risk assessment.

High-throughput PBTK models for in vitro to in vivo extrapolation

INTRODUCTION

Toxicity data are unavailable for many thousands of chemicals in commerce and the environment. Therefore, risk assessors need to rapidly screen these chemicals for potential risk to public health. High-throughput screening (HTS) for in vitro bioactivity, when used with high-throughput toxicokinetic (HTTK) data and models, allows characterization of these thousands of chemicals.

AREAS COVERED

This review covers generic physiologically based toxicokinetic (PBTK) models and high-throughput PBTK modeling for in vitro-in vivo extrapolation (IVIVE) of HTS data. We focus on 'httk', a public, open-source set of computational modeling tools and in vitro toxicokinetic (TK) data.

EXPERT OPINION

HTTK benefits chemical risk assessors with its ability to support rapid chemical screening/prioritization, perform IVIVE, and provide provisional TK modeling for large numbers of chemicals using only limited chemical-specific data. Although generic TK model design can increase prediction uncertainty, these models provide offsetting benefits by increasing model implementation accuracy. Also, public distribution of the models and data enhances reproducibility. For the httk package, the modular and open-source design can enable the tool to be used and continuously improved by a broad user community in support of the critical need for high-throughput chemical prioritization and rapid dose estimation to facilitate rapid hazard assessments.

In silico exploration of hydroxylated polychlorinated biphenyls as estrogen receptor β ligands by 3D-QSAR, molecular docking and molecular dynamics simulations

Hydroxylated polychlorinated biphenyls (HO-PCBs), as the major metabolites of PCBs, have been reported to act as estrogen receptor β (ERβ) agonists. However, the chemical-biological interactions governing their activities toward ERβ have not been elucidated. Therefore, three dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics (MD) simulations, to the best of our knowledge, for the first time were performed to explore the correlation between the structures and activities. The best 3D-QSAR model presented higher predictive ability (R²_cv=0.543, R²_pred=0.5793/R²_cv=0.543, R²_pred=0.6795) based on comparative molecular field analysis (CoMFA) and comparative similarity indices analysis (CoMSIA), respectively. At the same time, the derived contour maps indicated the important structural features required for improving the activity. Furthermore, molecular docking studies and MD simulations predicted the binding mode and the interactions between the ligand and the receptor. All the results would lead to a better understanding of the specific mechanism of HO-PCBs on estrogen receptor β (ERβ).Communicated by Ramaswamy H. Sarma.

Impact of Nonylphenols and Polyhalogenated Compounds in Follicular Fluid on the Outcome of Intracytoplasmic Sperm Injection

Endocrine-disrupting chemicals (EDCs) interfere with the mammalian hormone system and alter its endo- and paracrine regulation. The goal of the present study was to examine the presence of 14 EDCs, including the technical mixture of nonylphenols and Mirex, in human follicular fluid (FF) and to find a potential correlation between endocrine active substances and a possible impact on female fertility. Furthermore, potential sources of EDC exposition regarding patients' lifestyle and socioeconomic factors were investigated. Human FF was collected from a total of 210 women undergoing intracytoplasmic sperm injection-treatment cycles because of male subfertility. The presence of EDCs was analyzed using gas chromatography coupled with mass spectrometry. Thirteen of the 14 investigated EDCs were present in every FF sample; compounds with the highest concentrations in FF were nonylphenol and Mirex. Nearly all kinds of EDCs led to significantly reduced maturation and fertilization rate. No significant influence of EDC concentration on the clinical pregnancy rate was observed for neither of the analyzed EDCs. Patients who obtained their clothes and textiles at fashion discounters displayed a higher amount of EDCs in their FF. In contrast, patients' residential area, source of food products, and nicotine or caffeine consumed were not associated with EDC accumulation. Clinicaltrials.gov NCT01385605 (11 July 2011).

The Role of Suspension Array Technology in Rapid Detection of Foodborne Pollutants: Applications and Future Challenges

Food safety is an important livelihood issue, which has always been focused attention by countries and governments all over the world. As food supply chains are becoming global, food quality control is essential for consumer protection as well as for the food industry. In recent years, a great part of food analysis is carried out using new techniques for rapid detection. As the first biochip technology that has been approved by the Food and Drug Administration (FDA), there is an increasing interest in suspension array technology (SAT) for food and environmental analysis with advantages of rapidity, high accuracy, sensitivity, and throughput. Therefore, it is important for researchers to understand the development and application of this technology in food industry. Herein, we summarized the principle and composition of SAT and its application in food safety monitoring. The utility of SAT in detection of foodborne microorganisms, residues of agricultural and veterinary drugs, genetically modified food and allergens in recent years is elaborated, and the further development direction of SAT is envisaged.

Maternal and Newborn Thyroid Hormone, and the Association With Polychlorinated Biphenyls (PCBs) Burden: The EHF (Environmental Health Fund) Birth Cohort

Background: Polychlorinated biphenyls (PCBs) are ubiquitous environmental contaminants found in human tissues. PCBs can be transferred through the placenta and may disrupt the maternal thyroid homeostasis, and affect fetal thyroid hormone production. Several studies have shown that intrauterine exposure to PCBs might be associated with abnormal levels of thyroid hormones in mothers and their offspring. Objectives: To examine the associations between environmental exposure to PCBs and thyroid hormone levels in mothers and newborns. Methods: The EHF-Assaf-Harofeh-Ichilov cohort includes 263 mothers-newborns dyads. A total of 157 mother-newborn dyads had both PCBs and thyroid function measures. Regression models were used to estimate associations between maternal PCB exposure and maternal and newborn thyroid function, controlling for possible confounders. Results: Four PCBs congeners were analyzed: PCBs 118, 138, 153, and 180. ∑PCBs median (IQR) level was 14.65 (2.83-68.14) ng/g lipids. The median maternal thyroid-stimulating hormone (TSH) level was 2.66 (0.70-8.23) μIU/ml, the median maternal free thyroxine (FT4) level was 12.44 (11.27-13.53) μg/dL, the median maternal thyroid peroxidase antibodies (TPO Ab) level was 9.6 (7.36-12.51) IU/mL. Newborns' median total thyroxine (T4) level was 14.8 (7.6-24.9) μg/dL. No association was found between exposure to different congeners or to ∑PCBs and maternal TSH, FT4, thyroglobulin autoantibodies (Tg Ab), TPO Ab and newborn total T4 levels. In multivariable analysis a 1% change in ∑PCBs level was significantly associated with a 0.57% change in maternal TSH levels in women with body mass index (BMI) < 19. The same association was observed for each of the studied PCB congeners. Maternal TPO Ab levels statistically significantly increased by 0.53 and 0.46% for 1% increase in PCB 118 and 153 congeners, respectively. In women with BMI > 25, the association between the PCBs levels and maternal TSH levels was in the opposite direction. No association was found in women with normal BMI (19-24.9). Conclusions: Background exposure to environmentally relevant concentrations of some PCBs can alter thyroid hormone homeostasis in pregnant women and might be associated with abnormal TSH levels and TPO-Ab in women with low BMI. However, these findings require further investigation.

Effects of endocrine disrupting chemicals on myelin development and diseases

In the central and peripheral nervous systems, myelin is essential for efficient conduction of action potentials. During development, oligodendrocytes and Schwann cells differentiate and ensure axon myelination, and disruption of these processes can contribute to neurodevelopmental disorders. In adults, demyelination can lead to important disabilities, and recovery capacities by remyelination often decrease with disease progression. Among environmental chemical pollutants, endocrine disrupting chemicals (EDCs) are of major concern for human health and are notably suspected to participate in neurodevelopmental and neurodegenerative diseases. In this review, we have combined the current knowledge on EDCs impacts on myelin including several persistent organic pollutants, bisphenol A, triclosan, heavy metals, pesticides, and nicotine. Besides, we presented several other endocrine modulators, including pharmaceuticals and the phytoestrogen genistein, some of which are candidates for treating demyelinating conditions but could also be deleterious as contaminants. The direct impacts of EDCs on myelinating cells were considered as well as their indirect consequences on myelin, particularly on immune mechanisms associated with demyelinating conditions. More studies are needed to describe the effects of these compounds and to further understand the underlying mechanisms in relation to the potential for endocrine disruption.

Serum level of PCBs and OCPs and leukocyte telomere length among adults in Tehran, Iran

Exposure to polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) may change leukocyte telomere length (TL) at the end of the DNA sequence. The purpose of this study was to investigate the association between PCBs and OCPs exposure with TL in Tehran adult males. Whole-blood samples were randomly taken from three hundred adult males in population-based cross-section study from October 2016 to November 2017. We studied the serum levels of PCBs, OCPs as well as socio-demographic characteristics of individuals. The quantitative PCR was used to investigate the number of the telomere (T) repeats to the number of a single copy gene. We measured the effect of each PCBs and OCPs congeners on TL using linear regressions adjusted for age, BMI, smoking, and dietary patterns. The median level of the six non-dioxin-likes, five dioxin-likes PCBs three OCPs and TL in the study population were 344.5, 306.0, 45.0 ng/g lipid and 5377.7 ± 573.4 base pairs, respectively. In the adjusted model, the percent difference in the TLs with exposure to Σnon-dioxin-like PCBs, Σdioxin-like PCBs, and OCPs were 1.93 (-0.70 to 5.4), 3.4 (1.8-8.3) and -2.4 (-0.80 to -6.2), respectively. In the fourth quartile compared to the first quartile, the percent difference in the TLs due to Σnon-dioxin-like PCBs, Σdioxin-like PCBs, and OCP exposure were 0.01 (-0.01 to 0.05), 10.3 (2.9-18.1) and -0.20 (-0.10 to -4.5), respectively. Exposures to ndl-PCBs and dl-PCBs (except for PCB28) were related to longer TLs, but OCPs exposure can be related to telomere shortening.

Undernutrition combined with dietary mineral oil hastens depuration of stored dioxin and polychlorinated biphenyls in ewes. 1. Kinetics in blood, adipose tissue and faeces

Food safety crises involving persistent organic pollutants [POPs, e.g. dioxins, polychlorinated biphenyls (PCBs), organochlorine pesticides] lead to systematic slaughter of livestock to prevent their entry into the food chain. Therefore, there is a need to develop strategies to depurate livestock moderately contaminated with POPs in order to reduce such economic and social damages. This study aimed to test a POPs depuration strategy based on undernutrition (37% of energy requirements) combined with mineral oil (10% in total dry matter intake) in nine non-lactating ewes contaminated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and PCBs 126 and 153. In order to better understand the underlying mechanisms of the depuration process, POPs kinetics and body lipids dynamics were followed concomitantly over 57-day of depuration in POPs storage (adipose tissue, AT), central distribution (blood) and excretion (faeces) compartments. Faecal POPs concentrations in underfed and mineral oil supplemented ewes increased by 2.0 to 2.6-fold, but not proportionally to lipids concentration which increased by 6-fold, compared to the control ewes. Nonetheless, after 57 days of depuration in undernutrition and mineral oil supplementation, AT POPs concentrations were 1.5 to 1.6-fold higher while serum concentrations remained unchanged compared to the control ewes. This was concomitant with a decrease by 2.7-fold of the AT estimated lipids weight along the depuration period. This reduction of the volume of the storage compartment combined with the increase of POPs faecal excretion in underfed and mineral oil supplemented ewes led to a reduction by 1.5-fold of the PCB 126 AT burden, while no changes were observed for TCDD and PCB 153 burdens (vs. no change for PCB 126 and increases for TCDD and PCB 153 AT burdens in control ewes). The original approach of this study combining the fine description at once of POPs kinetic and of body lipids dynamic improved our understanding of POPs fate in the ruminant.

Annual changes in concentrations and health risks of PCDD/Fs, DL-PCBs and organochlorine pesticides in ambient air based on the Global Monitoring Plan in São Paulo

Ambient air contains a number of persistent organic pollutants (POPs), to which inhalation exposure has drawn worldwide concern. However, information regarding annual changes in the concentrations and health risks of POPs in the ambient air of São Paulo, Brazil, are limited. This study provides comprehensive information on annual changes in polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), and 10 groups of organochlorine pesticides (OCPs) in the ambient air of São Paulo between 2010 and 2015 based on the Global Monitoring Plan. The mass concentrations of the studied POPs (PCDD/Fs, DL-PCBs, and OCPs) showed declining trends from 2010 to 2015 (from 2.65 × 10^-2 to 1.33 × 10^-2 pg m^-3, from 9.89 × 10^-2 to 3.12 × 10^-2 pg m^-3, and from 0.313 to 0.100 ng m^-3, respectively), which might be due to the decrease of non-intentional emissions. The carcinogenic risk (CR) and non-carcinogenic risk (Non-CR) of the studied POPs were 1.48 × 10^-11 to 6.08 × 10^-7 and 3.44 × 10^-8 to 3.34 × 10^-3, respectively, which are lower than the generally accepted threshold values (10^-6/10^-5 and 1 for CR and Non-CR, respectively), suggesting that the health risks posed by the studied POPs were acceptable. PCDD/Fs had the highest CR (6.08 × 10^-8-4.81 × 10^-7), whereas the 95th percentile CR of DL-PCBs and nine of the OCPs were lower than 10^-7, suggesting that among the studied POPs, PCDD/Fs in the ambient air warrant special attention. The 95th percentile CRs of dichlorodiphenyltrichloroethane (2.30 × 10^-8), dieldrin (1.30 × 10^-8), hexachlorocyclohexanes (1.05 × 10^-8), heptachlor (8.97 × 10^-9), hexachlorobenzene (6.47 × 10^-9), chlordane (5.89 × 10^-9), heptachlor epoxide (1.42 × 10^-9), aldrin (1.33 × 10^-9), and mirex (2.71 × 10^-10) in ambient air were relatively low, suggesting that their threats to human health were negligible. In general, PCDD/Fs, DL-PCBs, and OCPs in the ambient air of São Paulo did not pose serious threats to human health during 2010-2015.

A longitudinal study of polychlorinated biphenyls and neuropsychological function among older adults from New York State

BACKGROUND

Cross-sectional studies have linked greater polychlorinated biphenyl (PCB) exposure to adverse neuropsychological effects in older adults, including learning, memory, and depressive symptoms. However, no studies among older adults have evaluated the association over time.

OBJECTIVES

To assess the effect of serum PCB levels on neuropsychological function over a 14-year period in a cohort of older men and women from a PCB-contaminated area of New York State.

METHODS

In 2000-2002, we assessed serum PCB levels and neuropsychological function (including the California Verbal Learning Test Trial 1 (CVLTT1) for verbal memory and learning, and the Beck Depression Index (BDI) for depressive symptoms) in 253 men and women, ages 55-74 years. A total of 116 (46%) persons repeated the PCB and neuropsychological assessment 14 years later. To assess the association over time, we used generalized estimating equations with clustering variables time, total PCB (∑PCB), and ∑PCB × time, and adjusted for baseline age, sex, smoking, and total serum-lipids. For statistically significant ∑PCB × time interactions, we evaluated the association between PCBs and either verbal memory and learning or depressive symptoms while holding ∑PCB constant at the 10th and 90th percentiles to clarify the direction of the interaction.

RESULTS

Over the study period, serum ∑PCB levels (wet-weight) declined by 22%, and were associated with different patterns of change over time for memory (∑PCB × Time β = 0.08 p = 0.009) and depressive symptoms (∑PCB × Time β = -0.16 p = 0.013). Specifically, verbal memory and learning decreased (β = -0.08 p = 0.008) and depressive symptoms increased (β = 0.17 p = 0.008) among persons with low exposure (∑PCB levels at the 10th percentile), while persons with high exposure (90th percentile) showed non-significant improvements.

DISCUSSION

In this cohort, declining ∑PCB levels were likely due at least in part to low rates of local fish consumption in recent decades, given the ban since 1976. The decreased verbal memory and learning and increased depressive symptoms over time among persons with low serum ∑PCB levels is consistent with studies of normative aging. However, the small improvements in those outcomes among those with high serum ∑PCB levels was unexpected. Healthy survivor selection bias or uncontrolled confounding may explain this result. It may also indicate that the neurotoxic impacts of PCBs in older adults are not permanent, but future studies are needed to confirm this possibility.

Exploring the associations of serum concentrations of PCBs, PCDDs, and PCDFs with walking speed in the U.S. general population: Beyond standard linear models

Studies have shown that persistent organic pollutants (POPs) can have various health effects. However, little is known about the effects of multiple chemicals with possible common sources of exposure on walking speed, a proxy index reflecting lower limb neuromuscular function and physical function. We simultaneously applied multiple linear and nonlinear statistical models to explore the complex exposure-response relationship between a mixture of 22 selected POPs and walking speed. A total of 14 polychlorinated biphenyls (PCBs), 3 polychlorinated dibenzo-p-dioxins (PCDDs), and 5 polychlorinated dibenzofurans (PCDFs) were measured in the serum of participants in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2002. Walking speed was measured during a physical examination. Linear regression (LR), least absolute shrinkage and selection operator (LASSO), and group LASSO were used to evaluate the linearity of mixtures, while restricted cubic spline (RCS) regression, random forest (RF), and Bayesian kernel machine regression (BKMR) models were used to evaluate the nonlinearity of mixtures. Potential confounders were adjusted in the above models. A total of 436 subjects were included in our final analysis. The results of the LR model did not identify any POP exposure that was significantly associated with walking speed. The LASSO results revealed an inverse association of one PCDD congener and two PCDF congeners with walking speed, while the group LASSO analysis identified PCDFs at the exposure level and at the group level. In the RCS analysis, two PCB congeners presented significant overall associations with walking speed. The PCB congener PCB194 showed statistically significant effects on the outcome (P = 0.01) when a permutation-based RF was used. The BKMR analysis suggested that PCBs and PCDFs (probabilities = 0.887 and 0.909, respectively) are potentially associated with walking speed. Complex statistical models, such as RCS regression, RF and BKMR models, can detect the nonlinear and nonadditive relationships between PCBs and walking speed, while LASSO and group LASSO can identify only the linear relationships between PCDFs and walking speed. Fully considering the influence of collinearity in each method during modelling can increase the comprehensiveness and reliability of conclusions in studies of multiple chemicals.

First polychlorinated biphenyls (PCBs) monitoring in seawater, surface sediments and marine fish communities of the Persian Gulf: Distribution, levels, congener profile and health risk assessment

Polychlorinated biphenyls (PCBs) are persistent organic pollutants that, due to their high toxicity, lipophilic property and widespread dispersal in the global environment, present a danger for human health and ecological systems. Although the inventory and use of PCBs are extensively reported worldwide, the status of PCBs in Iran is still unknown. In this study, the concentrations of PCBs were determined in the environmental matrices and in five commercially important fish species from Larak coral Island, Persian Gulf, Iran, in winter and summer 2015. A positive correlation was found among PCBs levels and congeners profiles in seawater (0.97-3.10 ng L^-1), surface sediments (2.95-7.95 ng g^-1dw) and fish samples (7.20-90.19 ng g^-1dw), indicating fish as suitable bioindicator of environmental PCBs contamination. In all matrices, a high contribution of light and medium chlorinated congeners was detected in both seasons. In fish, the higher PCBs levels were found for both sexes in both seasons in liver and kidney than other tissues (skin, gonad, muscle) due to their high lipid content and PCBs lipophilicity. More importantly, the risks for human health associated with fish consumption were also evaluated, and it was found that all the toxicity indices measured for PCBs were within the World Health Organization (WHO) permissible limit of food consumption. However, it is highly recommended to inform the local population about potential risks attributable to dietary incorporation of locally caught fish, and establish a surveillance monitoring programme on PCBs in this region.

In silico toxicity evaluation of dioxins using structure-activity relationship (SAR) and two-dimensional quantitative structure-activity relationship (2D-QSAR)

Prediction of pEC₅₀ values of dioxins binding with the aryl hydrocarbon receptor (AhR) is of great significance for exploring how dioxins induce toxicity in human body and evaluating their environmental behaviors and risks. To reveal the factors that influence the toxicity of dioxins, provide more accurate mathematical models for predicting the pEC₅₀ values of dioxins, and supplement the toxicity database of persistent organic pollutants, qualitative structure-activity relationship (SAR) and two-dimensional quantitative structure-activity relationship (2D-QSAR) were used in this study. The research objects in this study were 60 organic compounds with pEC₅₀ values and 162 compounds without pEC₅₀ values, which included polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxins (PCDDs), and polybrominated dibenzo-p-dioxins (PBDDs). The qualitative structure-activity relationship (SAR) was performed first and concluded that halogen substitutions at any of the 2, 3, 7, and 8 sites increased the pEC₅₀ value of the compound. Moreover, two-dimensional quantitative structure-activity relationship (2D-QSAR) models were established by employing multiple linear regression (MLR) method and artificial neural network (ANN) algorithm to investigate the factors affecting the pEC₅₀ values of dioxins molecules. MLR was used to establish the well-understood linear model and ANN was used to establish a more accurate non-linear model. Both models have good fitting, robustness, and predictive ability. Importantly, the ability of dioxins binding to AhR is mainly determined by molecular descriptors including E1m, SM09_AEA (dm), RDF065u, F05 [Cl-Cl], and Neoplastic-80. In addition, the pEC₅₀ values of the 162 dioxins without toxicity data were predicted by MLR and ANN models, respectively.

Persistent Halogenated Organic Pollutants in Surface Water in a Megacity: Distribution Characteristics and Ecological Risks in Wuhan, China

Surface water pollution in megacities is strongly linked to human and environmental health, and surface water quality has deteriorated sharply recently because of increasing persistent halogenated organic pollutant (HOP) concentrations. In the present study, we collected 112 water samples from 14 lakes and 11 drinking water sources in Wuhan, China, and analyzed them for two typical groups of HOPs: polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs). The mean values of the ΣPCB concentrations were 4.34 and 10.05 ng L^-1 in winter and summer, respectively. For ΣPBDE concentrations, the mean values were 0.88 and 1.53 ng L^-1 in winter and summer, respectively. The PCB and PBDE concentrations at most sites in summer were significantly higher than those in winter, probably because of heavy stormwater runoff in summer. The degree of urbanization predicted from the population density was positively correlated with ΣPCB concentrations in the drinking water sources in summer. PBDE and PCB composition analysis suggested the major sources were penta-BDE and Aroclor mixtures. Risk assessments showed the PBDEs in water from the Zhuankou site exceeded the threshold set by the European Union, which could result in adverse effects on aquatic organisms. Negligible noncarcinogenic risks were found for PCBs and PBDEs in the surface water with regard to drinking and bathing. However, the carcinogenic risks of PCBs for bathing in surface water were higher than the safe level of 1.00 × 10^-6, implying that the surface water in Wuhan is not safe for bathing.

The potential of recycled materials used in agriculture to contaminate food through uptake by livestock

The potential for contaminant uptake from recycled materials used in livestock farming, to animal tissues and organs, was investigated in three practical modular studies involving broiler chickens, laying chickens and pigs. Six types of commercially available recycled materials were used either as bedding material for chickens or as fertilizer for cropland that later housed outdoor reared pigs. The contaminants studied included regulated contaminants e.g. polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, dioxins) and polychlorinated biphenyls (PCBs), but related contaminants such as polybrominated diphenylethers (PBDEs), hexabrominated cyclododecane (HBCDD), polychlorinated naphthalenes (PCNs), polybrominated dioxins (PBDD/Fs) and perfluoroalkyl substances (PFAS) were also investigated. Contaminant occurrence in the recycled materials was verified prior to the studies and the relationship to tissue and egg concentrations in market ready animals was investigated using a weights of evidence approach. Contaminant uptake to animal tissues and eggs was observed in all the studies but the extent varied depending on the species and the recycled material. PCBs, PBDEs, PCDD/Fs, PCNs and PFAS showed the highest potential to transfer, with laying chickens showing the most pronounced effects. PBDD/Fs showed low concentrations in the recycled materials, making it difficult to evaluate potential transfer. Higher resulting occurrence levels in laying chickens relative to broilers suggests that period of contact with the materials may influence the extent of uptake in chickens. Bio-transfer factors (BTFs) estimated for PCDD/F and PCBs showed a greater magnitude for chicken muscle tissue relative to pigs with the highest values observed for PCBs in laying chickens. There were no significant differences between BTFs for the different chicken tissues which contrasted with the high BTF values for pigs liver relative to muscle. The study raises further questions which require investigation such as the effects of repeated or yearly application of recycled materials as fertilizers, and the batch homogeneity/consistency of available recycled materials.

Identifying sex differences arising from polychlorinated biphenyl exposures in toxicant-associated liver disease

Exposures to persistent environmental pollutants like polychlorinated biphenyls (PCBs) has been associated with liver diseases such as toxicant-associated steatohepatitis (TASH). However, previously published PCB hepatotoxicity studies evaluated mostly male animal models. Moreover, epidemiologic studies on PCB-exposed cohorts evaluating sex differences are scarce. Therefore, the objective of this study was to examine hepato-toxicological responses of PCB exposures in the context of sex-dependent outcomes. Male and female C57Bl/6 mice were exposed to Aroclor 1260 (20 mg/kg), and PCB126 (20 μg/kg), by gavage for two weeks. Female mice appeared to be more sensitive to PCB-induced hepatotoxic effects as manifested by increased liver injury markers, namely, hepatic Serpine1 expression. Additionally, compared to their male counterparts, PCB-exposed females exhibited dysregulated hepatic gene expression favoring lipid accumulation rather than lipid breakdown; accompanied by dyslipidemia. Sex differences were also observed in the expression and activation of PCB targets such as the epidermal growth factor receptor (EGFR) while PCB-induced pancreatic toxicity was similar in both sexes. Importantly, PCB exposure appeared to cause pro-androgenic, anti-estrogenic along with sex-dependent thyroid hormone effects. The overall findings demonstrated that the observed PCB-mediated hepatotoxicity was sex-dependent; confirming the existence of sex differences in environmental exposure-induced markers of TASH and warrants further investigation.

Evidence for Aryl hydrocarbon Receptor-Mediated Inhibition of Osteoblast Differentiation in Human Mesenchymal Stem Cells

Multipotent mesenchymal stem cells (MSCs) maintain the ability to differentiate into adipogenic, chondrogenic, or osteogenic cell lineages. There is increasing concern that exposure to environmental agents such as aryl hydrocarbon receptor (AhR) ligands, may perturb the osteogenic pathways responsible for normal bone formation. The objective of the current study was to evaluate the potential of the prototypic AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to disrupt osteogenic differentiation of human bone-derived MSCs (hBMSCs) in vitro. Primary hBMSCs from three donors were exposed to 10 nM TCDD and differentiation was interrogated using select histological, biochemical, and transcriptional markers of osteogenesis. Exposure to 10 nM TCDD resulted in an overall consistent attenuation of alkaline phosphatase (ALP) activity and matrix mineralization at terminal stages of differentiation in primary hBMSCs. At the transcriptional level, the transcriptional regulator DLX5 and additional osteogenic markers (ALP, OPN, and IBSP) displayed attenuated expression; conversely, FGF9 and FGF18 were consistently upregulated in each donor. Expression of stem cell potency markers SOX2, NANOG, and SALL4 decreased in the osteogenic controls, whereas expression in TCDD-treated cells resembled that of undifferentiated cells. Coexposure with the AhR antagonist GNF351 blocked TCDD-mediated attenuation of matrix mineralization, and either fully or partially rescued expression of genes associated with osteogenic regulation, extracellular matrix, and/or maintenance of multipotency. Thus, experimental evidence from this study suggests that AhR transactivation likely attenuates osteoblast differentiation in multipotent hBMSCs. This study also underscores the use of primary human MSCs to evaluate osteoinductive or osteotoxic potential of chemical and pharmacologic agents in vitro.

Patterns of PCB exposure among Akwesasne adolescents: The role of dietary and inhalation pathways

AIM

The objective of this study is to determine if consumption of fish and other dietary elements are related to the serum PCB levels of a group of adolescents. A dietary pattern approach is used to provide a more complete dietary exposure profile rather than a single food/group approach. Additionally, dietary patterns are examined in relation to traditional PCB groupings as well as derived PCB congener profiles.

PARTICIPANTS/SETTING AND METHODS

The sample is comprised of 246 Mohawk adolescents between the ages of 10-16.9 years of age residing at the Akwesasne Mohawk Nation. Food frequency data was collected and serum PCB levels were (101 congeners) quantitated during a cross-sectional study investigating adolescent exposure to environmental pollutants.

RESULTS

Principal component analysis identified four dietary patterns: "well-rounded" "snacks and sweets" "fruits and vegetables" "fish and dairy" and four PCB congener profiles: "1248-like", Persistent/"1260-like", "mono-ortho", and "1254-like". In a multiple regression models, the "fish and dairy" dietary or traditional PCB determinants (age, sex, prior breastfeeding, BMI, pattern) were each predictors of one or more of three of the identified PCB congener profiles. However, the "1248-like" pattern was not related to either dietary pattern or any of the typical PCB determinants, suggesting an alternative source/exposure pathway for this congener profile.

CONCLUSION

Even relatively low levels of fish consumption within the composite dietary matrix of adolescents at Akwesasne remains a pathway of exposure to postnatally acquired PCBs. In addition, there is evidence of an unidentified, perhaps airborne, exposure pathway that warrants further attention as this congener profile accounted for 50% of the total variance within the adolescents' serum PCB levels.

Trust in Whom? Dioxin, Organizations, Risk Perception, and Fish Consumption in Michigan's Saginaw Bay Watershed

Trust is generally recognized as important for risk-relevant behavior but research suggests that trust in different organizations may have varying effects. This research advances the literature by testing two hypotheses which postulate that this variability can be explained by risk perception. We collected data from 351 anglers regarding their trust in nine organizations whose efforts are relevant to dioxin contamination in Michigan's Saginaw Bay Watershed, risk perceptions, and self-reports of risky behavior (i.e., consumption of local fish identified as especially likely to contain contaminants). As hypothesized (H1), the negative effect of trust in two agencies-the Michigan Department of Natural Resources (MDNR) and a Michigan Department of Health and Human Services-sponsored River Walker Program (RWP)-on risky behavior was significantly mediated by risk perception but these effects differed from each other such that trust in the MDNR was associated with increased perceptions of risk while trust in the RWP was associated with decreased perceptions of benefit. Also as hypothesized (H2), the positive effect of trust in Dow Chemical Company on risky behavior was significantly mediated by risk perception such that increased trust in Dow was associated with reduced risk perception. The current results lend credence to arguments regarding the importance of specificity in the target of trust and advance this literature by suggesting that differential effects on risk perception help explain this variability. Thus, organizations whose efforts focus on risk communication appear ideally situated to reduce risky behavior through a negative impact on risk perception. Other organizations, however, may run the risk of increasing risky behavior if their efforts result in reduced perceptions of risk.

Embryonic effects of an environmentally relevant PCB mixture in the domestic chicken

Studies were conducted to develop methods to assess the effects of a complex mixture of polychlorinated biphenyls (PCBs) in the domestic chicken (Gallus domesticus). Treatments were administered by egg injection to compare embryonic effects of an environmentally relevant PCB congener mixture in the domestic chicken over a range of doses. Chicken eggs were injected with the PCB mixture with a profile similar to that found in avian eggs collected on the upper Hudson River, New York, USA, at doses that spanned 0 to 98 μg/g egg. Eggs were hatched in the laboratory to ascertain hatching success. In the domestic chicken, the median lethal dose was 0.3 μg/g. These data demonstrate adverse effects of an environmentally relevant PCB mixture and provide the basis for further work using in vitro and other models to characterize the potential risk to avian populations. Environ Toxicol Chem 2018;37:2513-2522. © 2018 SETAC.

Polychlorinated biphenyls (PCBs) as sentinels for the elucidation of Arctic environmental change processes: a comprehensive review combined with ArcRisk project results

Polychlorinated biphenyls (PCBs) can be used as chemical sentinels for the assessment of anthropogenic influences on Arctic environmental change. We present an overview of studies on PCBs in the Arctic and combine these with the findings from ArcRisk-a major European Union-funded project aimed at examining the effects of climate change on the transport of contaminants to and their behaviour of in the Arctic-to provide a case study on the behaviour and impact of PCBs over time in the Arctic. PCBs in the Arctic have shown declining trends in the environment over the last few decades. Atmospheric long-range transport from secondary and primary sources is the major input of PCBs to the Arctic region. Modelling of the atmospheric PCB composition and behaviour showed some increases in environmental concentrations in a warmer Arctic, but the general decline in PCB levels is still the most prominent feature. 'Within-Arctic' processing of PCBs will be affected by climate change-related processes such as changing wet deposition. These in turn will influence biological exposure and uptake of PCBs. The pan-Arctic rivers draining large Arctic/sub-Arctic catchments provide a significant source of PCBs to the Arctic Ocean, although changes in hydrology/sediment transport combined with a changing marine environment remain areas of uncertainty with regard to PCB fate. Indirect effects of climate change on human exposure, such as a changing diet will influence and possibly reduce PCB exposure for indigenous peoples. Body burdens of PCBs have declined since the 1980s and are predicted to decline further.

Signatures of chlorinated dioxins and furans along the exposure path - The relation between vegetation and soil

Polychlorinated dibenzo-p-dioxins and dibenzo-furans (PCDD/Fs) belong to the most toxic persistent organic environmental pollutants. Therefore, knowledge about their fate along the exposure path is of special concern. In order to comprehend the transfer of PCDD/Fs across different environmental compartments, PCDD/F concentrations in plants and in soil were evaluated. Pairs of soil and plant samples were selected according to the shortest distance between sampling points. At 15 sites PCDD/F concentrations in spruce needles and in forest humus layers where compared. Summer conditions were evaluated on the basis of 8 sites with ryegrass- and grassland topsoil samples. Autumn conditions were addressed using 7 sites with curly kale and topsoil samples under grassland. Correlation analyses of the PCDD/F congener profiles for plant- and soil samples were conducted. The correlations were compared to influencing site (e.g. local temperature) and spatial as well as temporal offset parameters. No governing parameter that decisively influenced the similarity between plant and soil signature became evident. By means of the toxicity factors of TEQ-WHO, tetra- and penta-PCDD/F homologues were assigned to the group of low-chlorinated homologues (lcH), and hexa-, hepta- and octa-PCDD/F homologues to the high-chlorinated homologues (hcH). lcH and hcH are presumed to differ in solubility, volatility and rate of degradation. The ratio of lcH/hcH revealed characteristic fingerprints that enabled the differentiation of the individual PCDD/F-plant and -soil pairs. Spruce-humus pairs showed a close relation during winter exposure times, while the lower summer concentrations were not reflected in the humus layer. Kale was exposed at the beginning of the season with elevated PCDD/F immissions, and showed a closer relation to grassland topsoil than did ryegrass. lcH/hcH proved as a simple criterion that can reveal related PCDD/F fingerprints of different environmental compartments despite signal attenuation due to decomposition, volatilization and particulate transport.

Editor's Highlight: PCB126 Exposure Increases Risk for Peripheral Vascular Diseases in a Liver Injury Mouse Model

The liver is vital for xenobiotic and endobiotic metabolism. Previously, we demonstrated that a compromised liver worsened toxicity associated with exposure to polychlorinated biphenyls (PCBs), through disruption of energy homeostasis. However, the role of a compromised liver in defining dioxin-like PCB126 toxicity on the peripheral vasculature and associated inflammatory diseases is yet to be studied. This study investigated the effects of PCB126 on vascular inflammation linked to hepatic dysfunction utilizing a liver injury mouse model. Male C57Bl/6 mice were fed either an amino acid control diet (CD) or a methionine-choline deficient (MCD) diet in this 14-week study. Mice were exposed to PCB126 (0.5 mg/kg) and analyzed for inflammatory, calorimetric and metabolic parameters. MCD diet-fed mice demonstrated steatosis, indicative of a compromised liver. Mice fed the MCD-diet and subsequently exposed to PCB126 manifested lower body fat mass, increased liver to body weight ratio and alterations in hepatic gene expression related to lipid and carbohydrate metabolism, implicating metabolic disturbances. PCB126-induced steatosis irrespective of the diet type, but only the MCD + PCB126 group exhibited steatohepatitis and fibrosis. Furthermore, PCB126 exposure in MCD-fed mice led to increased plasma inflammatory markers such as Icam-1, plasminogen activator inhibitor-1 and proatherogenic trimethylamine-N-oxide, suggesting inflammation of the peripheral vasculature that is characteristic of atherosclerosis. Taken together, our data provide new evidence of a link between a compromised liver, PCB-mediated hepatic inflammation and vascular inflammatory markers, suggesting that environmental pollutants can promote crosstalk between different organ systems, leading to inflammatory disease pathologies.

Screening of organic pollutants in pet hair samples and the significance of environmental factors

Organic pollutants (OPs) represent a wide range of chemicals that are potentially harmful for human and wildlife health. Many of these pollutants have been identified as endocrine disruptors that can alter hormonal balance producing adverse biological effects such as neurotoxicity, reproductive disorders, carcinogenicity and hepatotoxicity. For years, hair has been selected as a non-invasive source to assess levels of animal contamination. In the present study, a multiclass screening method for determining about 60 organic pollutants in pet hair was designed and validated for qualitative and quantitative purposes. Concentrations from different classes of organochlorine, and organophosphate pesticides (OCPs, and OPPs), polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (NDL-PCBs and DL-PCBs), polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs) were identified in the selected pet hair samples from Ourense (NW, Spain). We detected most of these pollutants in the selected hair pets. The mean concentrations found ranged from 89 to 6556ng/g for OPEs, from 8.6 to 1031ng/g for PAHs, from 8.6 to 256ng/g for PBDEs, from 29 to 184ng/g for OPPs, from 0.29 to 139 for OCPs, from 0.30 to 59ng/g for NDL-PCBs and from 1.2 to 14ng/g for DL-PCBs. To our knowledge, this is the first study to document the presence of OPs in pets from North-West Spain and it could provide baseline information for future monitoring of OPs in the area.

Peripubertal serum dioxin concentrations and subsequent sperm methylome profiles of young Russian adults

BACKGROUND

The association of exposure to endocrine disrupting chemicals in the peripubertal period with subsequent sperm DNA methylation is unknown.

OBJECTIVE

We examined the association of peripubertal serum 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) concentrations with whole-genome bisulfite sequencing (WGBS) of sperm collected in young adulthood.

METHODS

The Russian Children's Study is a prospective cohort of 516 boys who were enrolled at 8-9 years of age and provided semen samples at 18-19 years of age. WGBS of sperm was conducted to identify differentially methylated regions (DMR) between highest (n = 4) and lowest (n = 4) peripubertal TCDD groups.

RESULTS

We found 52 DMRs that distinguished lowest and highest peripubertal serum TCDD concentrations. One of the top scoring networks, "Cellular Assembly and Organization, Cellular Function and Maintenance, Carbohydrate Metabolism", identified estrogen receptor alpha as its central regulator.

CONCLUSION

Findings from our limited sample size suggest that peripubertal environmental exposures are associated with sperm DNA methylation in young adults.

Persistent organic pollutants and mortality in the United States, NHANES 1999-2011

BACKGROUND

Persistent organic pollutants (POPs) are environmentally and biologically persistent chemicals that include polybrominated diphenyl ethers (PBDEs), per- and polyfluoroalkyl substances (PFASs), polychlorinated biphenyls (PCBs), and organochlorine (OC) pesticides. Currently, data on the associations between exposure to POPs and the risk of mortality in the U.S. population is limited. Our objective was to determine if higher exposure to POPs is associated with greater risk of all-cause, cancer, heart/cerebrovascular disease, or other-cause mortality.

METHODS

Analyses included participants aged 60 years and older from the 1999-2006 National Health and Nutrition Examination Surveys (NHANES). We included 483 participants for analyses of PBDEs, 1043 for PFASs, and 461 for PCBs, and 1428 for OC pesticides. Exposures to POPs were estimated using biomarkers measured in serum. Mortality status through December 31, 2011 was obtained from public-use, linked mortality files. We used Cox proportional hazard models to quantify the associations of interest. Where we observed an association, we explored effect modification by sex, body mass index, smoking status, and albuminuria. We also explored the combined effect of PBDEs and OC pesticides in the subsample of participants with measures of both analytes.

RESULTS

Serum measurements of PBDEs, PFASs, and PCBs were not clearly associated with increased all-cause or cause-specific mortality in older Americans. Beta-hexachlorocyclohexane was associated with an increased risk of all-cause mortality [HR per 1 SD increase =1.18, 95% CI = 1.01, 1.38]. Oxychlordane [HR = 1.15 95% CI 1.06, 1.25], p,p'-DDE [HR = 1.12, 95% CI = 1.02, 1.23], trans-nonachlor [HR = 1.11, 95% CI = 1.04, 1.18], and beta-hexachlorocyclohexane [HR = 1.25, 95% CI = 1.03, 1.52] were associated with increased risk of other-cause mortality. Exploratory analyses suggested associations between OC pesticides and other-cause mortality were modified by sex. Exploratory analyses also suggested that the combination of high PBDE and high OC pesticide exposure had a stronger than expected adverse effect on all-cause mortality.

CONCLUSION

Higher exposure to beta-hexachlorocyclohexane, an OC pesticide, is associated with increased all-cause mortality and higher exposure to four OC pesticides is associated with increased non-cancer, non-heart/cerebrovascular disease mortality in U.S. adults 60 years or older. These associations may be modified by sex or exposure to other POPs.

Recent trends in common chemical feed and food contaminants in Israel

In February 2014 a new law was approved by the Israeli parliament, namely the Control of Animal Feed Law. The law intends to regulate the production and marketing of animal feed. In preparation for the law's implementation in 2017, we have assessed the current feed and food safety challenges in Israel in recent years in association with the presence of common undesirable contaminants in various common feed and food commodities. Tight collaboration between regulatory authorities and feed/food industry, enhanced feed and food quality monitoring, transparency of survey results and readily accessible and reliable information for the public about health hazards of chemical contaminants, will guarantee the safety and quality of food and feed.

Source contributions to total concentrations and carcinogenic potencies of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in ambient air: a case study in Suzhou City, China

The potential source categories and source contributions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in ambient air from Suzhou City, China, were performed by principal component analysis-multiple linear regression (PCA-MLR) and positive matrix factorization (PMF). The carcinogenic potencies of PCDD/Fs were quantitatively apportioned based on the positive matrix factorization-toxic equivalent concentration (PMF-TEQ) method. The results of the present study were summarized as follows. (1) The total concentrations and toxic equivalent concentrations of PCDD/Fs (∑PCDD/Fs and TEQ) in ambient air from Suzhou City were 1.34-42.80 pg N m^-3 and 0.081-1.22 pg I-TEQ N m^-3, respectively. (2) PCA-MLR suggested that industrial combustion (IC), electric arc furnaces (EAFs) and secondary aluminum smelters (ALSs), unleaded gas-fueled vehicle sources (UGFVs), ALSs, and hazardous solid waste incinerators (HSWIs) could be the primary PCDD/F contributors, accounting for 13.2, 16.7, 35.5, 19.4, and 15.2% of ∑PCDD/Fs, respectively. (3) PMF and PMF-TEQ indicated that EAFs (carbon steel), UGFVs, IC, ALSs, municipal solid waste incinerators (MSWIs) and hospital waste incinerators (HWIs), and HSWIs contributed 10.9, 10.9, 42.8, 11.3, 10.7, and 13.4% to ∑PCDD/Fs, but contributed 8.3, 12.3, 50.3, 12.7, 6.0, and 10.4% to carcinogenic potencies of PCDD/Fs. This study was the first attempt to quantitatively apportion the source-specific carcinogenic potencies of PCDD/Fs in ambient air.

Exposure to endocrine disruptors during adulthood: consequences for female fertility

Endocrine disrupting chemicals are ubiquitous chemicals that exhibit endocrine disrupting properties in both humans and animals. Female reproduction is an important process, which is regulated by hormones and is susceptible to the effects of exposure to endocrine disrupting chemicals. Disruptions in female reproductive functions by endocrine disrupting chemicals may result in subfertility, infertility, improper hormone production, estrous and menstrual cycle abnormalities, anovulation, and early reproductive senescence. This review summarizes the effects of a variety of synthetic endocrine disrupting chemicals on fertility during adult life. The chemicals covered in this review are pesticides (organochlorines, organophosphates, carbamates, pyrethroids, and triazines), heavy metals (arsenic, lead, and mercury), diethylstilbesterol, plasticizer alternatives (di-(2-ethylhexyl) phthalate and bisphenol A alternatives), 2,3,7,8-tetrachlorodibenzo-p-dioxin, nonylphenol, polychlorinated biphenyls, triclosan, and parabens. This review focuses on the hypothalamus, pituitary, ovary, and uterus because together they regulate normal female fertility and the onset of reproductive senescence. The literature shows that several endocrine disrupting chemicals have endocrine disrupting abilities in females during adult life, causing fertility abnormalities in both humans and animals.