DNA damage from polycyclic aromatic hydrocarbons measured by benzo[a]pyrene-DNA adducts in mothers and newborns from Northern Manhattan, the World Trade Center Area, Poland, and China

Polycyclic Aromatic Hydrocarbons (PAHs) in the Environment: Occupational Exposure, Health Risks and Fertility Implications

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds with fused aromatic rings, primarily derived from combustion processes and environmental pollutants. This narrative review discusses the most relevant studies on PAHs, focusing on their sources, environmental and occupational exposure, and effects on human health, emphasizing their roles as carcinogenic, mutagenic, and teratogenic agents. The primary pathways for human exposure to PAHs are through the ingestion of contaminated food (mainly due to some food processing methods, such as smoking and high-temperature cooking techniques), the inhalation of ambient air, and the smoking of cigarettes. Coke oven workers are recognized as a high-risk occupational group for PAH exposure, highlighting the need for appropriate strategies to mitigate these risks and safeguard worker health. PAHs are metabolized into reactive intermediates in the body, which can lead to DNA damage and promote the development of various health conditions, particularly in environments with high exposure levels. Chronic PAH exposure has been linked to respiratory diseases, as well as cardiovascular problems and immune system suppression. Furthermore, this review underscores the significant impact of PAHs on reproductive health. The results of the reported studies suggest that both male and female fertility can be compromised due to oxidative stress, DNA damage, and endocrine disruption caused by PAH exposure. In males, PAHs impair sperm quality, while, in females, they disrupt ovarian function, potentially leading to infertility, miscarriage, and birth defects. Fetal exposure to PAHs is also associated with neurodevelopmental disorders. Given the extensive and detrimental health risks posed by PAHs, this review stresses the importance of stringent environmental regulations, occupational safety measures, and public health initiatives to mitigate exposure and safeguard reproductive and overall health.

Periconceptional polycyclic aromatic hydrocarbon levels in maternal hair and fetal risk for congenital heart defects

BACKGROUND

Congenital heart defects (CHDs) have a complex etiology, and environmental factors play an important role in their occurrence. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous chemicals, and some have teratogenic potential. However, few studies have examined PAHs exposure and CHD risk. We investigated the association between PAHs in maternal scalp hair and CHD risk.

METHODS

A case-control study involving 170 severe CHD cases and 170 healthy controls was conducted, and the concentrations of 11 PAHs in maternal hair grown during the periconceptional period were quantified. A generalized linear mixed model (GLMM) was used to determine the effects of each PAHs on the risk for CHDs. Weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to assess the overall effects of the 11-PAHs mixture on the risk for CHDs.

RESULTS

The median concentration of chrysene (CHR) was higher in CHD cases (9.75 ng/g) than in controls (6.50 ng/g). In GLMM, higher levels of CHR were associated with a 4.88-fold greater risk for CHDs (95 % confidence interval [CI]: 2.69-8.89). In WQS regression, higher levels of PAHs mixture were associated with a 2.03-fold greater CHD risk (95 % CI: 1.75-2.31), and CHR had the highest weighting (weighted 0.9346). In BKMR, CHD risks increased steadily with the levels of the PAHs mixture. CHR showed a toxic effect when the other PAHs were fixed at their 25th, 50th, or 75th percentile. No interactions among PAHs were found.

CONCLUSIONS

When examined individually, a high concentration of CHR in periconceptional maternal hair was associated with an increased risk for CHDs. When considering the 11 PAHs together, higher levels of the PAHs mixture were associated with increased odds of CHD occurrence.

DNA Methylation as a Molecular Mechanism of Carcinogenesis in World Trade Center Dust Exposure: Insights from a Structured Literature Review

The collapse of the World Trade Center (WTC) buildings in New York City generated a large plume of dust and smoke. WTC dust contained human carcinogens including metals, asbestos, polycyclic aromatic hydrocarbons (PAHs), persistent organic pollutants (POPs, including polychlorinated biphenyls (PCBs) and dioxins), and benzene. Excess levels of many of these carcinogens have been detected in biological samples of WTC-exposed persons, for whom cancer risk is elevated. As confirmed in this structured literature review (n studies = 80), all carcinogens present in the settled WTC dust (metals, asbestos, benzene, PAHs, POPs) have previously been shown to be associated with DNA methylation dysregulation of key cancer-related genes and pathways. DNA methylation is, therefore, a likely molecular mechanism through which WTC exposures may influence the process of carcinogenesis.

Childhood exposure to polycyclic aromatic hydrocarbons is associated with emotional and behavioral problems in adolescence: a longitudinal study in China

PURPOSE

The aim of this study was to investigate the relationship between childhood polycyclic aromatic hydrocarbon (PAH) exposure and emotional and behavioral problems in adolescence.

METHODS

Participants included 998 school-age children aged 7-12 years (514 girls and 484 boys). Metabolite concentrations of four PAHs (1-hydroxypyrene [1-OHPyr], 2-hydroxynaphthalene [2-OHNap], 2-hydroxyfluorine [2-OHFlu], and 9-hydroxyphenanthrene [9-OHPhe]) were measured in urine samples at baseline (Dec 2014-Dec 2015). During adolescence, we measured emotional and behavioral problems in study participants. We used logistic regression models to assess the effects of different levels of PAH metabolite concentrations on emotional and behavioral problems for boys and girls, separately.

RESULTS

Boys exposed to 1-OHPyr and 2-OHFlu had a significantly higher risk of externalizing problems (OR: 2.62, 95% CI: 1.09 ~ 6.29; OR: 2.92, 95% CI: 1.15 ~ 7.42). 2-OHNap exposure faced a higher risk of internalizing problems (OR: 3.85, 95% CI: 1.28 ~ 11.58; OR: 3.63, 95% CI: 1.13 ~ 11.63) and externalizing problems (OR: 4.27, 95% CI: 1.44 ~ 12.70; OR: 4.68, 95% CI: 1.49 ~ 14.73). Moreover, boys exposed to 9-OHPhe exhibited a significant risk of anxiety (OR: 2.84, 95% CI: 1.01 ~ 7.97; OR: 3.00, 95% CI: 1.04 ~ 8.68). Similarly, girls exposed to 9-OHPhe had a significant risk of anxiety (OR: 2.41, 95% CI: 1.25 ~ 4.64).

CONCLUSION

Childhood PAH exposures are associated with emotional and behavioral problems in adolescence, and boys seem more susceptible than girls.

Geographical approach analysis of the impact of air pollution on newborn intrauterine growth and cord blood DNA damage in Mexico City

BACKGROUND

Few epidemiologic studies have focused on the specific source of ambient air pollution and adverse health effects in early life. Here, we investigated whether air pollutants from different emission sources were associated with decreased birth anthropometry parameters and increased DNA adduct formation in mother-child pairs residing in the Mexico City Metropolitan Area (MCMA).

METHODS

This cross-sectional study included 190 pregnant women recruited during their last trimester of pregnancy from two hospitals at MCMA, and a Modeling Emissions Inventory (MEI) to calculate exposure to ambient air pollutants from different emissions sources (area, point, mobile, and natural) for two geographical buffers 250 and 750 m radii around the participants households.

RESULTS

Contaminants were positively correlated with umbilical cord blood (UCB) adducts, but not with maternal blood (MB) adducts. PM10 emissions (area and point sources, overall emissions), PM2.5 (point sources), volatile organic compounds (VOC), total organic compounds (TOC) from point sources were positively correlated with UCB adducts. Air pollutants emitted from natural sources were correlated with a decrease in MB and UCB adducts. PM10 and PM2.5 were correlated (p < 0.05) with a decrease in birth weight (BW), birth length (BL) and gestational age at term (GA). In multivariate analyses adjusted for potential confounders, PM10 was associated with an increase in UCB adducts. PM10 and PM2.5 from overall emissions were associated with a decrease in BW, BL and GA at term.

IMPACT

Results suggested higher susceptibility of newborns compared to mothers to damage related to ambient air pollution. PMs are associated with birth anthropometry parameters and DNA damage in adjusted models, highlighting the need for more strict regulation of PM emissions.

Using bioactive compounds to mitigate the formation of typical chemical contaminants generated during the thermal processing of different food matrices

With rising consumer awareness of health and wellness, the demand for enhanced food safety is rapidly increasing. The generation of chemical contaminants during the thermal processing of food materials, including polycyclic aromatic hydrocarbons, heterocyclic aromatic amines, and acrylamide happens every day in every kitchen all around the world. Unlike extraneous chemical contaminants (e.g., pesticides, herbicides, and chemical fertilizers), these endogenic chemical contaminants occur during the cooking process and cannot be removed before consumption. Therefore, much effort has been invested in searching for ways to reduce such thermally induced chemical contaminants. Recently, the addition of bioactive compounds has been found to be effective and promising. However, no systematic review of this practical science has been made yet. This review aims to summarize the latest applications of bioactive compounds for the control of chemical contaminants during food thermal processing. The underlying generation mechanisms and the toxic effects of these chemical contaminants are discussed in depth to reveal how and why they are suppressed by the addition of certain bioactive ingredients. Examples of specific bioactive compounds, such as phenolic compounds and organic acids, as well as their application scenarios, are outlined. In the end, outlooks and expectations for future development are provided based on a comprehensive summary and reflection of references.

Dissecting the long-term neurobehavioral impact of embryonic benz[a]anthracene exposure on zebrafish: Social dysfunction and molecular pathway activation

Benz[a]anthracene (BaA), a prevalent environmental contaminant within the polycyclic aromatic hydrocarbon class, poses risks to both human health and aquatic ecosystems. The impact of BaA on neural development and subsequent social behavior patterns remains inadequately explored. In this investigation, we employed the zebrafish as a model to examine the persisting effects of BaA exposure on social behaviors across various developmental stages, from larvae, juveniles to adults, following embryonic exposure. Our findings indicate that BaA exposure during embryogenesis yields lasting neurobehavioral deficits into adulthood. Proteomic analysis highlights that BaA may impair neuro-immune crosstalk in zebrafish larvae. Remarkably, our proteomic data also hint at the activation of the aryl hydrocarbon receptor (AHR) and cytochrome P450 1A (CYP1A) pathway by BaA, leading to the hypothesis that this pathway may be implicated in the disruption of neuro-immune interactions, contributing to observable behavioral disruptions. In summary, our findings suggest that early exposure to BaA disrupts social behaviors, such as social ability and shoaling behaviors, from the larval stage through to maturity in zebrafish, potentially through the detrimental effects on neuro-immune processes mediated by the AHR-CYP1A pathway.

Case-Control Study of the Association between Single Nucleotide Polymorphisms of Genes Involved in Xenobiotic Detoxification and Antioxidant Protection with the Long-Term Influence of Organochlorine Pesticides on the Population of the Almaty Region

The association of genetic polymorphisms with the individual sensitivity of humans to the action of pesticide pollution is being actively studied in the world. The aim of this study was a molecular epidemiological analysis of candidate polymorphisms of genes involved in pesticide metabolism, detoxification, and antioxidant protection. Some of the selected polymorphisms also relate to susceptibility to cancer and cardiovascular, respiratory, and immune system diseases in individuals exposed to pesticides for a long time. For a case-control study of a unique cohort of people exposed to organochlorine pesticides for 10 years or more were chosen, a control cohort was selected that matched with the experimental group by the main population characteristics. PCR-PRLF and genome-wide microarray genotyping (GWAS) methods were used. We identified 17 polymorphisms of xenobiotic detoxification genes and 27 polymorphisms of antioxidant defense genes, which had a significantly high statistical association with the negative impact of chronic pesticide intoxication on human health. We also found 17 polymorphisms of xenobiotic detoxification genes and 12 polymorphisms of antioxidant defense genes that have a protective effect. Data obtained added to the list of potential polymorphisms that define a group at high risk or resistant to the negative effects of pesticides.

Interactions between Benzo(a)pyrene exposure and genetic polymorphisms of AhR signaling pathway on missed abortion

Benzo(a)pyrene (BaP) is an environmental pollutant widely exposed to human beings. While the relationship between BaP and missed abortion is few understood. To explore the association between missed abortion and BaP, genetic polymorphisms of AhR pathway, we recruited 112 cases women with missed abortion and 137 controls women with normal pregnancy from Shanxi, China. The BPDE-DNA adducts level in the case group was higher than that in the control group (P < 0.001). The subjects were categorized according to the tertiles of BPDE-DNA adduct concentrations: T1 ( Collapse

Key Words

• AhR signaling pathway
• BaP
• genetic polymorphisms
• missed abortion

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MESH Headings

• Pregnancy
• Humans
• Female
• DNA Adducts
• Benzo(a)pyrene/toxicity
• 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/metabolism
• Abortion, Missed
• Signal Transduction
• Polymorphism, Genetic

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Affiliation(s)

Sha Liu Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
Mei Han Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
Jiayu Zhang Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
Jingru Ji Department of Obstetrics, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi, China
Yanfei Wu Department of Obstetrics, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi, China Department of Chinese Medicine, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi, China
Junni Wei Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China

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Prenatal airborne polycyclic aromatic hydrocarbon exposure, altered regulation of peroxisome proliferator-activated receptor gamma (Ppar)γ, and links with mammary cancer

Environmental exposure to polycyclic aromatic hydrocarbons (PAH) has been shown to be associated with chronic disease outcomes through multiple mechanisms including altered regulation of the transcription factor peroxisome proliferator-activated receptor gamma (Ppar) γ. Because PAH exposure and Pparγ each have been associated with mammary cancer, we asked whether PAH would induce altered regulation of Pparγ in mammary tissue, and whether this association may underlie the association between PAH and mammary cancer. Pregnant mice were exposed to aerosolized PAH at proportions that mimic equivalent human exposures in New York City air. We hypothesized that prenatal PAH exposure would alter Pparγ DNA methylation and gene expression and induce the epithelial to mesenchymal transition (EMT) in mammary tissue of offspring (F1) and grandoffspring (F2) mice. We also hypothesized that altered regulation of Pparγ in mammary tissue would associate with biomarkers of EMT, and examined associations with whole body weight. We found that prenatal PAH exposure lowered Pparγ mammary tissue methylation among grandoffspring mice at postnatal day (PND) 28. However, PAH exposure did not associate with altered Pparγ gene expression or consistently with biomarkers of EMT. Finally, lower Pparγ methylation, but not gene expression, was associated with higher body weight among offspring and grandoffspring mice at PND28 and PND60. Findings suggest additional evidence of multi-generational adverse epigenetic effects of prenatal PAH exposure among grandoffspring mice.

Developmental exposure to polycyclic aromatic hydrocarbons (PAHs): Focus on benzo[a]pyrene neurotoxicity

Polycyclic Aromatic Hydrocarbons (PAHs) are a class of ubiquitous organic compounds produced during the incomplete combustion or pyrolysis of organic material. Dietary source is the main route for PAH human exposure by environmental contamination, food industrial processing or domestic cooking methods. The most studied PAH is benzo[a]pyrene (B[a]P), due to its harmful and multiple effects on human health: in addition to its well-known carcinogenic effects, emerging evidence indicates that B[a]P also induces neurotoxicity earlier and at lower doses than B[a]P-induced carcinogenicity making B[a]P neurotoxicity relevant to human health risk assessment. Developmental neurotoxicity of B[a]P has indeed received increasing attention: both human and experimental studies provide evidence of detrimental effects of prenatal or early postnatal B[a]P exposure, even at low doses. Indeed, in some of the multi-dose animal studies, maximal adverse effects were observed at lower B[a]P doses, according to a non-monotonic dose-response curve typical of endocrine-disrupting compounds. In substantial agreement with epidemiological studies, both rodents and zebrafish developmentally exposed to B[a]P exhibit long-term changes in multiple behavioural domains, in the absence of overt toxicological effects at birth (e.g. body weight and morphologic abnormalities). Notably, most targeted behavioural responses converge on locomotor activity and emotional profile, often, but not always, leading to a disinhibitory/hyperactive profile.

Associations between prenatal exposure to polycyclic aromatic hydrocarbons and thyroid hormones in umbilical cord blood

We explored the association between maternal urinary polycyclic aromatic hydrocarbon (PAH) metabolites and thyroid hormones in umbilical cord blood in 120 pairs of pregnant women and newborns. Maternal urinary PAH metabolites were measured using high-performance liquid chromatography with tandem mass spectrometry. Thyroid hormones were measured using a flow fluorescence assay. The dose-response relationship between PAH metabolites and thyroid hormones was analyzed using the generalized linear model and restricted cubic spline model. Results showed that ƩOH PAHs in maternal urine had a negative effect on triiodothyronine (T3). Associations between maternal urinary PAH metabolites and thyroid hormones in umbilical cord blood plasma were observed. Prenatal exposure to PAHs could affect neonatal thyroid hormones, thereby disrupting neonatal thyroid function.

Bioinorganic Nanoparticles for the Remediation of Environmental Pollution: Critical Appraisal and Potential Avenues

Nowadays, environmental pollution has become a critical issue for both developed and developing countries. Because of excessive industrialization, burning of fossil fuels, mining and exploration, extensive agricultural activities, and plastics, the environment is being contaminated rapidly through soil, air, and water. There are a variety of approaches for treating environmental toxins, but each has its own set of restrictions. As a result, various therapies are accessible, and approaches that are effective, long-lasting, less harmful, and have a superior outcome are extensively demanded. Modern research advances focus more on polymer-based nanoparticles, which are frequently used in drug design, drug delivery systems, environmental remediation, power storage, transformations, and other fields. Bioinorganic nanomaterials could be a better candidate to control contaminants in the environment. In this article, we focused on their synthesis, characterization, photocatalytic process, and contributions to environmental remediation against numerous ecological hazards. In this review article, we also tried to explore their recent advancements and futuristic contributions to control and prevent various pollutants in the environment.

Polycyclic aromatic hydrocarbons in aquatic media of Turkey: A systematic review of cancer and ecological risk

Polycyclic aromatic hydrocarbons (PAHs) have gathered worldwide attention due to their carcinogenicity and toxicity. This paper aims to review and extend current knowledge on PAHs in aquatic environments in Turkey, where expansion of the marine industry has caused contamination concerns. To assess cancer and ecological risks associated with PAHs, we systematically reviewed 39 research articles. Mean measured concentrations of total PAHs ranged from 61 to 249,900 ng L^-1 in surface waters, 1 to 209,400 ng g^-1 in sediments, and 4 to 55,000 ng g^-1 in organisms. Estimated cancer risks from concentrations in organisms were higher than those from surface waters and sediments. Negative ecosystem impacts of petrogenic PAHs were estimated to be larger than those of pyrogenic origin, despite the predominance of the latter. Overall, the Marmara, Aegean, and Black seas are highly-polluted and need remedial action, while further study is needed to confirm the status of other water bodies.

Benzo[a]pyrene toxicokinetics in humans following dietary supplementation with 3,3'-diindolylmethane (DIM) or Brussels sprouts

Utilizing the atto-zeptomole sensitivity of UPLC-accelerator mass spectrometry (UPLC-AMS), we previously demonstrated significant first-pass metabolism following escalating (25-250 ng) oral micro-dosing in humans of [14C]-benzo[a]pyrene ([14C]-BaP). The present study examines the potential for supplementation with Brussels sprouts (BS) or 3,3'-diindolylmethane (DIM) to alter plasma levels of [14C]-BaP and metabolites over a 48-h period following micro-dosing with 50 ng (5.4 nCi) [14C]-BaP. Volunteers were dosed with [14C]-BaP following fourteen days on a cruciferous vegetable restricted diet, or the same diet supplemented for seven days with 50 g of BS or 300 mg of BR-DIM® prior to dosing. BS or DIM reduced total [14C] recovered from plasma by 56-67% relative to non-intervention. Dietary supplementation with DIM markedly increased Tmax and reduced Cmax for [14C]-BaP indicative of slower absorption. Both dietary treatments significantly reduced Cmax values of four downstream BaP metabolites, consistent with delaying BaP absorption. Dietary treatments also appeared to reduce the T1/2 and the plasma AUC(0,∞) for Unknown Metabolite C, indicating some effect in accelerating clearance of this metabolite. Toxicokinetic constants for other metabolites followed the pattern for [14C]-BaP (metabolite profiles remained relatively consistent) and non-compartmental analysis did not indicate other significant alterations. Significant amounts of metabolites in plasma were at the bay region of [14C]-BaP irrespective of treatment. Although the number of subjects and large interindividual variation are limitations of this study, it represents the first human trial showing dietary intervention altering toxicokinetics of a defined dose of a known human carcinogen.

Kinetics of Benzo(a)pyrene biodegradation and bacterial growth in sandy soil by Sphingobacterium spiritovorum

Biodegradation is the economically viable solution to restore land contaminated by hazardous pollutants such as benzo(a)pyrene (BaP). The present study focuses on the biodegradation of benzo(a)pyrene by Sphingobacterium spiritovorum in contaminated soil. The biodegradation kinetics and bacterial growth were evaluated while the biokinetic model that described the benzo(a)pyrene biodegradation was established. The Monod, Haldane, Powell and Edward models were used to model the bacterial growth in benzo(a)pyrene contaminated soil. Excel template was developed with Fourth order Runga-Kutta numerical algorithm to find the biokinetic parameters of the complex non-linear regression model. An Excel Solver function was used to obtain reasonable best-fit values of kinetic parameters. The Haldane and Edward models are well fit to describe the growth trend and model the kinetics of benzo(a)pyrene biodegradation. Enzyme substrate inhibition is the critical factor that affects the benzo(a)pyrene degradation by S. spiritovorum, which the model defines physically. The results demonstrated that removing benzo(a)pyrene showed positive interaction between substrate inhibition, the concentration of benzo(a)pyrene and sorption of the contaminants on soil particles.

Polycyclic aromatic hydrocarbon and its effects on human health: An overeview

Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals of considerable environmental significance. PAHs are chemical contaminants of fused carbon and hydrogen aromatic rings, basically white, light-yellow, or solid compounds without color. Natural sources of pollution are marginal or less significant, such as volcanic eruptions, natural forest fires, and moorland fires that trigger lightning bursts. The significant determinants of PAH pollution are anthropogenic pollution sources, classified into four groups, i.e., industrial, mobile, domestic, and agricultural pollution sources. Humans can consume PAHs via different routes, such as inhalation, dermal touch, and ingestion. The Effect of PAHs on human health is primarily based on the duration and route of exposure, the volume or concentration of PAHs to which one is exposed, and the relative toxicity of PAHs. Many PAHs are widely referred to as carcinogens, mutagens, and teratogens and thus pose a significant danger to human health and the well-being of humans. Skin, lung, pancreas, esophagus, bladder, colon, and female breast are numerous organs prone to tumor development due to long-term PAH exposure. PAH exposure may increase the risk of lung cancer as well as cardiovascular disease (CVD), including atherosclerosis, thrombosis, hypertension, and myocardial infarction (MI). Preclinical studies have found a relationship between PAH exposure, oxidative stress, and atherosclerosis. In addition, investigations have discovered a relationship between PAH exposure at work and CVD illness and mortality development. This review aims to explain PAH briefly, its transportation, its effects on human health, and a relationship between environmental exposures to PAHs and CVD risk in humans.

A systematic review of the use of silicone wristbands for environmental exposure assessment, with a focus on polycyclic aromatic hydrocarbons (PAHs)

BACKGROUND

Exposure assessment is critical for connecting environmental pollutants to health outcomes and evaluating impacts of interventions or environmental policies. Silicone wristbands (SWBs) show promise for multi-pollutant exposure assessment, including polycyclic aromatic hydrocarbons (PAHs), a ubiquitous class of toxic environmental pollutants.

OBJECTIVE

To review published studies where SWBs were worn on the wrist for human environmental exposure assessments and evaluate the ability of SWBs to capture personal exposures, identify gaps which need to be addressed to implement this tool, and make recommendations for future studies to advance the field of exposure science through utilization of SWBs.

METHODS

We performed a systematic search and a cited reference search in Scopus and extracted key study descriptions.

RESULTS

Thirty-nine unique studies were identified, with analytes including PAHs, pesticides, flame retardants, and tobacco products. SWBs were shipped under ambient conditions without apparent analyte loss, indicating utility for global exposure and health studies. Nineteen articles detected a total of 60 PAHs in at least one SWB. Correlations with other concurrent biological and air measurements indicate the SWB captures exposure to flame retardants, tobacco products, and PAHs.

SIGNIFICANCE

SWBs show promise as a simple-to-deploy tool to estimate environmental and occupational exposures to chemical mixtures, including PAHs.

Prenatal urinary metabolites of polycyclic aromatic hydrocarbons and toddler cognition, language, and behavior

BACKGROUND

Animal and epidemiological studies suggest that prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) may negatively impact toddler neurodevelopment.

METHODS

We investigated this association in 835 mother-child pairs from CANDLE, a diverse pregnancy cohort in the mid-South region of the U.S. PAH metabolite concentrations were measured in mid-pregnancy maternal urine. Cognitive and Language composite scores at ages 2 and 3 years were derived from the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-3). Behavior Problem and Competence scores at age 2 were derived from the Brief Infant and Toddler Social Emotional Assessment (BITSEA). We used multivariate linear or Poisson regression to estimate associations with continuous scores and relative risks (RR) of neurodevelopment delay or behavior problems per 2-fold increase in PAH, adjusted for maternal health, nutrition, and socioeconomic status. Secondary analyses investigated associations with PAH mixture using Weighted Quantile Sum Regression (WQS) with a permutation test extension.

RESULTS

1- hydroxypyrene was associated with elevated relative risk for Neurodevelopmental Delay at age 2 (RR = 1.20, 95% CI: 1.03,1.39). Contrary to hypotheses, 1-hydroxynaphthalene was associated with lower risk for Behavior Problems at age 2 (RR = 0.90, 95% CI: 0.83,0.98), and combined 1- and 9-hydroxyphenanthrene was associated with 0.52-point higher (95% CI: 0.11,0.93) Cognitive score at age 3. For PAH mixtures, a quintile increase in hydroxy-PAH mixture was associated with lower Language score at age 2 (βwqs = -1.59; 95% CI: -2.84, -0.34; p_permutation = 0.07) and higher Cognitive score at age 3 (βwqs = 0.96; 95% CI: 0.11, 1.82; p_permutation = 0.05). All other estimates were consistent with null associations.

CONCLUSION

In this large southern U.S. population we observed some support for adverse associations between PAHs and neurodevelopment.

Developmental toxicity testing of unsubstituted and methylated 4- and 5-ring polycyclic aromatic hydrocarbons using the zebrafish embryotoxicity test

The present study evaluates the in vitro developmental toxicity of 4- and 5-ring PAHs including benz[a]anthracene and benzo[a]pyrene and six of their monomethylated congeners, and dibenz[a,h]anthracene using the zebrafish embryotoxicity test (ZET). In general, the tested PAHs induced various developmental effects in the zebrafish embryos including unhatched embryos, no movement and circulation, yolk sac and pericardial edemas, deformed body shape, and cumulative mortality at 96 h post fertilization (hpf). The alkyl substituent on different positions of the aromatic ring of the PAHs appeared to change their in vitro developmental toxicity. Comparison to a previously reported molecular docking study showed that the methyl substituents may affect the interaction of the PAHs with the aryl hydrocarbon receptor (AhR) which is known to play a role in the developmental toxicity of some PAHs. Taken together, our results show that methylation can either increase or decrease the developmental toxicity of PAHs and suggest this may relate to effects on the molecular dimensions and resulting consequences for interactions with the AhR.

Extravillous trophoblast migration and invasion: Impact of environmental chemicals and pharmaceuticals

During pregnancy, the migration and invasion of extravillous trophoblasts (EVTs) into the maternal uterus is essential for proper development of the placenta and fetus. During the first trimester, EVTs engraft and remodel maternal spiral arteries allowing for efficient blood flow and the transfer of essential nutrients and oxygen to the fetus. Aberrant migration of EVTs leading to either shallow or deep invasion into the uterus has been implicated in a number of gestational pathologies including preeclampsia, fetal growth restriction, and placenta accreta spectrum. The migration and invasion of EVTs is well-coordinated to ensure proper placentation. However, recent data point to the ability of xenobiotics to disrupt EVT migration. These xenobiotics include heavy metals, endocrine disrupting chemicals, and organic contaminants and have often been associated with adverse pregnancy outcomes. In most instances, xenobiotics appear to reduce EVT migration; however, there are select examples of enhanced motility after chemical exposure. In this review, we provide an overview of the 1) current experimental approaches used to evaluate EVT migration and invasion in vitro, 2) ability of environmental chemicals and pharmaceuticals to enhance or retard EVT motility, and 3) signaling pathways responsible for altered EVT migration that are sensitive to disruption by xenobiotics.

Association between prenatal polycyclic aromatic hydrocarbons and infantile allergic diseases modified by maternal glutathione S-transferase polymorphisms: results from the MOCEH birth cohort

Background

Prenatal exposure to polycyclic aromatic hydrocarbons (PAH) has been linked to allergic disease onset. Variations in the glutathione S-transferase (GST) gene family can impact the progression of allergic diseases. We sought to examine the association between prenatal PAH exposure and infantile allergic diseases in 6-month-old infants, and how maternal glutathione S-transferase M1 (GSTM1) or T1 (GSTT1) polymorphism affects the association between prenatal PAH exposure and allergic diseases in the Mothers and Children's Environmental Health (MOCEH) study.

Methods

The study sample comprised 349 infants and their mothers from the MOCEH study, for whom 1-hydroxypyrene (1-OHP) and 2-naphthol were measured in both the early period of pregnancy and late period of pregnancy. An infant was deemed to be affected by an allergic disease if diagnosed with or if developed at least one of the allergic diseases. A logistic regression analysis was performed to study the association between urinary 1-OHP and 2-naphthol levels during pregnancy and allergic diseases in 6-month-old infants. Furthermore, analyses stratified by maternal GSTM1 or GSTT1 present/null polymorphisms were performed.

Results

The risk of allergic diseases in 6-month-old infants was significantly increased in accordance with an increase in urinary 1-OHP during the early period of pregnancy (odds ratio [OR]: 1.84; 95% confidence interval [CI]: 1.05, 3.23; by one log-transformed unit of 1-OHP μg/g creatinine). The increased risk of infantile allergic diseases associated with urinary 1-OHP during the early period of pregnancy was limited to the maternal GSTT1 null type (OR: 2.69; 95% CI: 1.17, 6.21, by one log-transformed unit of 1-OHP μg/g creatinine); however, the Relative Excess Risk due to Interaction was not statistically significant.

Conclusions

The present study found that infantile allergic diseases could be affected by intrauterine PAH exposure, particularly in the early prenatal period and the risk was limited to the maternal GSTT1 null type.

AHR/ROS-mediated mitochondria apoptosis contributes to benzo[a]pyrene-induced heart defects and the protective effects of resveratrol

Benzo[a]pyrene (BaP), a prototypical polycyclic aromatic hydrocarbon, is widely present in the environment. BaP-induced heart defects have been frequently reported, but the underlying molecular mechanisms remain elusive. Here, we found that BaP increased heart malformations in zebrafish embryos in a concentration-dependent manner, which were attenuated by supplementation with either CH223191 (CH), an aryl hydrocarbon receptor (AHR) inhibitor, or N-acetyl-l-cysteine (NAC), a reactive oxygen species (ROS) scavenger. While CH and NAC both inhibited BaP-induced ROS generation, NAC had no effect on BaP-induced AHR activation. We further demonstrated that BaP increased mitochondrial ROS, decreased mitochondrial membrane potential, and caused endogenous apoptosis, with all these effects being counteracted by supplementation with either CH or NAC. Resveratrol (RSV), a natural AHR antagonist and ROS scavenger, also counteracted the heart malformations caused by BaP. Further experiments showed that RSV attenuated BaP-induced oxidative stress, mitochondrial damage and apoptosis, but had no significant effect on AHR activation. In conclusion, our findings show that BaP induces oxidative stress via AHR activation, which causes mitochondria-mediated intrinsic apoptosis, resulting in heart malformations in zebrafish embryos, and that RSV had a protective effect against BaP-induced heart defects mainly by inhibiting oxidative stress rather than through antagonism of AHR activity.

Circulating microRNAs as biomarkers of environmental exposure to polycyclic aromatic hydrocarbons: potential and prospects

Exposure to polycyclic aromatic hydrocarbons (PAHs) produced from various pyrogenic and petrogenic sources in the environment has been linked to a variety of toxic effects in the human body. Genome-wide analyses have shown that microRNAs (miRNAs) can function as novel and minimally invasive biomarkers of environmental exposure to PAHs. The objective of this study is to explore miRNA signatures associated with early health effects in response to chronic environmental exposure to PAHs. We systematically searched Scopus and PubMed databases for studies related to exposure of PAHs with changes in miRNA expression patterns that represent early health effects in the exposed population. Based on previous studies, we included 15 cell-based and 9 each of animal model and human population-based studies for assessment. A total of 11 differentially expressed PAH-responsive miRNAs were observed each in two or more cell-based studies (miR-181a and miR-30c-1), animal model studies (miR-291a and miR-292), and human population-based studies (miR-126, miR-142-5p, miR-150-5p, miR-24-3p, miR-27a-3p, miR-28-5p, and miR-320b). In addition, miRNAs belonging to family miR-122, miR-199, miR-203, miR-21, miR-26, miR-29, and miR-92 were found to be PAH-responsive in both animal model and cell-based studies; let-7, miR-126, miR-146, miR-30, and miR-320 in both cell-based and human population-based studies; and miR-142, miR-150, and miR-27 were found differentially expressed in both animal model and human population-based studies. The only miRNA whose expression was found to be altered in all the three groups of studies is miR-34c. Association of environmental exposure to PAHs with altered expression of specific miRNAs indicates that selective miRNAs can be used as early warning biomarkers in PAH-exposed population.

Curcumin Suppresses the Lipid Accumulation and Oxidative Stress Induced by Benzo[a]pyrene Toxicity in HepG2 Cells

Benzo[a]pyrene (B[a]P) is a potentially hepatotoxic group-1 carcinogen taken up by the body through ingestion of daily foods. B[a]P is widely known to cause DNA and protein damages, which are closely related to cell transformation. Accordingly, studies on natural bioactive compounds that attenuate such chemical-induced toxicities have significant impacts on public health. This study aimed to uncover the mechanism of curcumin, the major curcuminoid in turmeric (Curcuma longa), in modulating the lipid accumulation and oxidative stress mediated by B[a]P cytotoxicity in HepG2 cells. Curcumin treatment reduced the B[a]P-induced lipid accumulation and reactive oxygen spicies (ROS) upregulation and recovered the cell viability. Cytochrome P450 family 1 subfamily A polypeptide 1 (CYP1A1) and Cytochrome P450 subfamily B polypeptide 1 (CYP1B1) downregulation resulting from decreased aryl hydrocarbon receptor (AhR) translocation into nuclei attenuated the effects of B[a]P-induced lipid accumulation and repressed cell viability, respectively. Moreover, the curcumin-induced reduction in ROS generation decreased the nuclear translocation of Nuclear factor erythroid-2-related factor 2 (Nrf2) and the expression of phase-II detoxifying enzymes. These results indicate that curcumin suppresses B[a]P-induced lipid accumulation and ROS generation which can potentially induce nonalcoholic fatty liver disease (NAFLD) and can shed a light on the detoxifying effect of curcumin.

Net volatilization of PAHs from the North Pacific to the Arctic Ocean observed by passive sampling

The North Pacific-Arctic Oceans are important compartments for semi-volatile organic compounds' (SVOCs) global marine inventory, but whether they act as a "source" or "sink" remains controversial. To study the air-sea exchange and fate of SVOCs during their poleward long-range transport, low-altitude atmosphere and surface seawater were measured for polycyclic aromatic hydrocarbons (PAHs) by passive sampling from July to September in 2014. Gaseous PAH concentrations (0.67-13 ng m^-3) were dominated by phenanthrene (Phe) and fluorene (Flu), which displayed an inverse correlation with latitude, as well as a significant linear relationship with partial pressure and inverse temperature. Concentrations of PAHs in seawater (1.8-16 ng L^-1) showed regional characteristics, with higher levels near the East Asia and lower values in the Bering Strait. The potential impact from the East Asian monsoon was suggested for gaseous PAHs, which - similar to PAHs in surface seawater - were derived from combustion sources. In addition, the data implied net volatilization of PAHs from seawater into the air along the entire cruise; fluxes displayed a similar pattern to regional and monthly distribution of PAHs in seawater. Our results further emphasized that air-sea exchange is an important process for PAHs in the open marine environments.

Diet, exposure to polycyclic aromatic hydrocarbons during pregnancy, and fetal growth: A comparative study of mothers and their fetuses in industrial and urban areas in Southwest Iran

The presence of polycyclic aromatic hydrocarbons (PAHs) in the fetal environment is a high-priority concern due to the fetus being more sensitive than adults to these ubiquitous xenobiotics. The aim of the present study was to compare the maternal and fetal serum levels of ΣPAHs and their effects on fetal growth in an industrial and an urban area in Southwest Iran. The industrial area was the petrochemical and gas area (PGA) of the Central District of Asaluyeh County and the urban area (UA) was the Central District of Bushehr County, Ninety-nine maternal serum (MS) and 99 cord serum (CS) samples from the PGA and 100 MS and 100 CS samples from the UA were collected during May 2018 to February 2019. The mean concentrations of ΣPAHs were significantly (p < 0.05) higher in the PGA than the UA in both MS (157.71 vs. 93.56 μg/L) and CS (155.28 vs. 93.19 μg/L) samples. Naphthalene (NAP) was the predominant PAH detected in all the studied samples. Significant negative associations were found between birth weight and anthracene (ANT) level in MS (β = -22.917, p = 0.032; weight decrement = 22.917 g for a 1 μg/L increase in ANT); head circumference and chrysene (CHR) level in MS (β = -0.206, p = 0.023; head circumference decrement = 0.206 cm for a 1 μg/L increase in CHR); and birth height and NAP level in CS (β = -0.20, p = 0.005; height decrement = 0.20 cm for a 1 μg/L increase in NAP). Maternal diet had a significant effect on the serum levels of PAHs. The results of this study showed that transmission of PAHs from mother to fetus through the cord blood is an important issue and mothers who live in industrial areas and consume PAH-containing foodstuffs, and their fetuses, are more at risk than those living in a non-industrial urban area.

Associations of prenatal exposure to polycyclic aromatic hydrocarbons with pubertal timing and body composition in adolescent girls: Implications for breast cancer risk

BACKGROUND

While animal data support an association between prenatal exposure to endocrine disrupting chemicals (EDCs) and altered mammary gland development and tumorigenesis, epidemiologic studies have only considered a few classes of EDCs in association with pubertal growth and development in girls. Polycyclic aromatic hydrocarbons (PAH) are a class of EDCs that have not been rigorously evaluated in terms of prenatal exposure and pubertal growth and development in girls.

OBJECTIVE

In a New York City birth cohort of Black and Hispanic girls (n = 196; recruited 1998-2006), we examined associations of prenatal PAH exposure with self-reported age at growth spurt onset, breast development onset and menarche, and clinical measures of adolescent body composition including body mass index, waist-to-hip ratio, and body fat measured at ages 11-20 years.

METHODS

We measured prenatal exposure to PAH using personal air monitoring data collected from backpacks worn by mothers during the third trimester of pregnancy (data available for all 196 girls) and biomarkers of benzo[α]pyrene-DNA adducts in umbilical cord blood (data available for 106 girls). We examined associations of prenatal PAH with the timing of pubertal milestones and adolescent body composition (11-20 years) using multivariable linear regression models adjusted for race/ethnicity, household public assistance status at birth, and age at outcome assessment. We also fit models further adjusted for potential mediators, including birthweight and childhood body size (BMI-for-age z-score measured at 6-8 years).

RESULTS

Girls in the highest versus lowest tertile of ambient exposure to PAH, based on a summary measure of eight carcinogenic higher-molecular weight non-volatile PAH compounds (Σ8 PAH), had a 0.90 year delay in growth spurt onset (95% confidence interval (CI) = 0.25, 1.55; n = 196), a 0.35 year delay in breast development onset (95% CI = -0.26, 0.95; n = 193), and a 0.59 year delay in menarche (95% CI = 0.06, 1.11; n = 191) in models adjusted for race/ethnicity and household public assistance at birth. The statistically significant associations for age at growth spurt onset and menarche were not impacted by adjustment for birthweight or childhood body size. No differences in BMI-for-age z-score, waist-to-hip ratio, or percent body fat were found between girls in the highest versus lowest tertile of ambient Σ8 PAH. Results were similar when we evaluated benzo[α]pyrene-DNA adduct levels.

DISCUSSION

Our results suggest that prenatal exposure to PAH might delay pubertal milestones in girls, but findings need to be replicated in other cohorts using prospectively collected data on pubertal outcomes.

Industrial polycyclic aromatic hydrocarbons (PAHs) emissions embodied in domestic trade in China in 2012

Atmospheric Polycyclic Aromatic Hydrocarbons (PAHs) emissions cause non-negligible damage to human health and well-being. Effective regional cooperation is urgently required to mitigate PAHs emissions to maintain satisfactory air quality. This study quantified and tracked China's PAHs emissions flows embodied in interprovincial trade. A production-based emissions inventory of 16 U.S. EPA priority PAHs based on commercial energy consumption in China in 2012 was compiled using the emissions factor approach. Then, a multiregional input-output model was constructed to reveal consumption-based emissions and to track the PAHs emissions embodied in the trade of 27 major sectors across 30 regions in China. Key structural paths were also identified using structural path analysis (SPA). In 2012, the total industrial energy-derived PAHs emissions were estimated to be 47.7 tons of BaP-toxic equivalents (8032.7 tons of mass). Shandong, Hebei, and Hubei accounted for more than 24.0% of the production-side PAHs emissions in the whole country. Approximately 30.8% of China's PAHs emissions were embodied in goods consumed outside of the province in which they were produced. PAHs flow tended to start in the western regions and ended in the eastern regions along the coast. The results of the SPA showed that critical paths, such as from the Metallurgy sector to the Construction sector, embodied a large amount of emissions and had the potential to affect the performance of the entire system. By paying attention to the consumption-based accounting as well as the production-based accounting of emissions and by focusing on vital transfer paths, policymakers can devise effective and targeted environmental protection and sustainable development policies in China.

DNA-SIP identification of phenanthrene-degrading bacteria undergoing bioaugmentation and natural attenuation in petroleum-contaminated soil

DNA-stable isotope probing (SIP) with ¹³C labeled phenanthrene (PHE) as substrate was used to identify specific bacterial degraders during natural attenuation (NA) and bioaugmentation (BA) in petroleum contaminated soil. BA, with the addition of a bacterial suspension mixture named GZ, played a significant role in PHE degradation with a higher PHE removal rate (∼90%) than that of NA (∼80%) during the first 3 days, and remarkably altered microbial communities. Of the five strains introduced in BA, only two genera, particularly, Ochrobactrum, Rhodococcus were extensively responsible for PHE-degradation. Six (Bacillus sp., Acinetobacter sp., Xanthomonas sp., Conexibacter sp., Acinetobacter sp. and Staphylococcus sp.) and seven (Ochrobactrum sp., Rhodococcus sp., Alkanindiges sp., Williamsia sp., Sphingobium sp., Gillisia sp. and Massilia sp.) bacteria responsible for PHE degradation were identified in NA and BA treatments, respectively. This study reports for the first time the association of Xanthomonas sp., Williamsia sp., and Gillisia sp. to PHE degradation.

Analysis of Single Nucleotide Variants (SNVs) Induced by Exposure to PM10 in Lung Epithelial Cells Using Whole Genome Sequencing

There are many epidemiological studies asserting that fine dust causes lung cancer, but the biological mechanism is not clear. This study was conducted to investigate the effect of PM₁₀ (particulate matter less than 10 μm) on single nucleotide variants through whole genome sequencing in lung epithelial cancer cell lines (HCC-827, NCI-H358) that have been exposed to PM₁₀. The two cell lines were exposed to PM₁₀ for 15 days. We performed experimental and next generation sequencing analyses on experimental group that had been exposed to PM₁₀ as well as an unexposed control group. After exposure to PM₁₀, 3005 single nucleotide variants were newly identified in the NCI-H358 group, and 4402 mutations were identified in the HCC-827 group. We analyzed these single nucleotide variants with the Mutalisk program. We observed kataegis in chromosome 1 in NCI-H358 and chromosome 7 in HCC-827. In mutational signatures analysis, the COSMIC mutational signature 5 was highest in both HCC-827 and NCI-H358 groups, and each cosine similarity was 0.964 in HCC-827 and 0.979 in the NCI-H358 group. The etiology of COSMIC mutational signature 5 is unknown at present. Well-designed studies are needed to determine whether environmental factors, such as PM₁₀, cause COSMIC mutational signature 5.

Polycyclic aromatic hydrocarbon exposure results in altered CRH, reproductive, and thyroid hormone concentrations during human pregnancy

Polycyclic aromatic hydrocarbons (PAHs) are byproducts of incomplete combustion reactions and are ubiquitous in the environment, leading to widespread human exposure via inhalation and ingestion pathways. PAHs have been implicated as endocrine disrupting compounds in previous animal and in vitro studies, but human studies are currently lacking. Pregnant women and their developing fetuses are particularly susceptible populations to environmental contaminants, in part because alterations in hormone physiology during gestation can have adverse consequences on the health of the pregnancy. We utilized data on 659 pregnant women from the PROTECT longitudinal birth cohort in Puerto Rico to assess associations between repeated measures of 8 urinary hydroxylated PAH (OH-PAH) metabolites and 9 serum hormones during gestation. Urine samples were collected at 3 study visits (median gestational ages of 18, 22, and 26 weeks at each visit, respectively) and serum samples were collected at the first and third study visits. Linear mixed effects models were used to ascertain longitudinal associations between OH-PAHs and hormones, and sensitivity analyses were employed to assess potential nonlinearity and differences in associations on the basis of fetal sex and timing of biomarker measurement. Among the multiple positive associations we observed between OH-PAHs and CRH, estriol, progesterone, T3, and the ratio of T3 to T4, and inverse associations with testosterone, the most notable are a 24.3% increase (95% CI: 13.0, 36.7) in CRH with an interquartile range (IQR) increase in 1-hydroxyphenanthrene and a 17.2% decrease (95% CI: 8.13, 25.4) in testosterone with an IQR increase in 1-hydroxynapthalene. Many associations observed were dependent on fetal sex, and some relationships showed evidence of nonlinearity. These findings demonstrate the importance of studying PAH exposures during pregnancy and highlight the potential complexity of their impacts on the physiology of human pregnancy.

Neural Tube Defects and ZIC4 Hypomethylation in Relation to Polycyclic Aromatic Hydrocarbon Exposure

Background

Epigenetic dysregulation is one of the postulated underlying mechanisms of neural tube defects (NTDs). Polycyclic aromatic hydrocarbons (PAHs), a group of environmental pollutants that are reported as a risk factor of NTDs, may cause decreased genome-wide DNA methylation. With DNA extracted from neural tissues, this study identified gene(s) whose hypomethylation was related to elevated risk for NTDs and examined whether its hypomethylation is related to PAH exposure.

Results

Using data profiled by Infinium HumanMethylation450 BeadChip array from 10 NTD cases and eight controls, ZIC4, CASP8, RAB32, RARA, and TRAF6 were identified to be the top five genes in NTD-related hypomethylated gene families. Among all identified genes, ZIC4 had the largest number of differently methylated CpG sites (n = 13) in the promoter region and 5′ UTR. Significantly decreased methylation in the ZIC4 promoter region and 5′ UTR was verified in an independent cohort of 80 cases and 32 controls (p < 0.001) utilizing the Sequenom EpiTYPER platform. Hypomethylation of ZIC4 was associated with a higher risk of NTDs [adjusted OR = 1.08; 95% confidence interval (CI): 1.03, 1.13] in a logistic regression model. Mean methylation levels in the promoter region and 5′ UTR of ZIC4 tended to be inversely associated with levels of high-molecular-weight PAHs in fetal liver among NTD fetuses (β [95% CI]: −0.045 [−0.091, 0.001], p = 0.054). Six and three CpG sites in the ZIC4 promoter region and 5′ UTR were inversely correlated with antioxidant indicators and protein oxidation markers (ρ: −0.45 to −0.75, p < 0.05) in fetal neural tissues, respectively. In a whole-embryo cultured mouse model, hypomethylation of the Zic4 promoter region and 5′ UTR and upregulation of Zic4 were observed, coupled with increased NTD rates after BaP exposure. The antioxidant N-acetyl-L-cysteine normalized the changes observed in the BaP exposure group.

Conclusion

Hypomethylation of the ZIC4 promoter region and 5′ UTR may increase the risk for NTDs; oxidative stress is likely to play a role in the methylation change of Zic4 in response to PAH exposure in NTD formation.

The Relationship Between Air Pollution and Cognitive Functions in Children and Adolescents: A Systematic Review

Air pollution has a negative impact on one's health and on the central nervous system. We decided to assess studies that evaluated the relationship between air pollution and cognitive functions in children and adolescents by reviewing studies that had been published between January 2009 and May 2019. We searched three major databases for original works (26 studies) and for studies using brain imaging methods based on MRI (six studies). Adverse effects of air pollutants on selected cognitive or psychomotor functions were found in all of the studies. Exposure to nitrogen dioxide, for example, was linked to impaired working memory, general cognitive functions, and psychomotor functions; particulate matter 2.5 was linked to difficulties in working memory, short-term memory, attention, processing speed, and fine motor function; black carbon was linked to poor verbal intelligence, nonverbal intelligence, and working memory; airborne copper was linked to impaired attentiveness and fine motor skills; isophorone was linked to lower mathematical skills; and polycyclic aromatic hydrocarbons in fetal life were linked to lower intelligence scores. The studies using MRI showed that high concentrations of air pollutants were linked to changes in the brain's white matter or lower functional integration and segregation in children's brain networks. In view of the global increase in air pollution, there is a need for further research to elucidate the relationship between air pollution and cognitive and motor development in children. According to some studies, neuroinflammation, the e4 allele of the apolipoprotein E gene, and gutathione-S-transferase gene polymorphism processes may play a role.

Exposure of nursing mothers to polycyclic aromatic hydrocarbons: Levels of un-metabolized and metabolized compounds in breast milk, major sources of exposure and infants' health risks

In this study, biomonitoring of nursing Portuguese mothers to polycyclic aromatic hydrocarbons (PAHs) exposure and assessment of potential health risks of their infants were performed through determination of 18 PAHs and 6 major metabolites (OH-PAHs) in breast milk. Concentrations of total PAHs ranged between 55.2 and 1119 ng/g fat, being naphthalene, dibenz(a,h)anthracene, benzo(g,h,i)perylene, and phenanthrene the most abundant compounds (68.4% of ∑PAHs). Benzo(a)pyrene, known carcinogenic, was not detected. Total levels of OH-PAHs ranged from 6.66 to 455 ng/g fat with 1-hydroxyphenanthrene, 1-hydroxynaphthalene and 1-hydroxyacenaphthene as major compounds (96% of ∑OH-PAHs). Concentrations of ∑PAHs and ∑OH-PAHs were strongly correlated between each other (r = 0.692; p ≤ 0.001) and moderately-to-strongly associated with individual compounds (0.203 < r < 0.841; p ≤ 0.001). The attained data suggest increased levels of PAHs in older nursing mothers (>30 years) and in those whose child had lower weight (up to 3.0 kg). Breast-fed infant presented a median PAHs daily intake of 1.41 μg/kg body weight (total benzo(a)pyrene equivalents of 0.0679 μg/kg) and were exposed to 0.024 μg/kg body weight of ∑PAH4 [benz(a)anthracene, benzo(b)fluoranthene, benzo(j)fluoranthene, and chrysene]. Although breast milk is a secure food for newborns, un-metabolized and metabolized PAHs should be included in biomonitoring surveillance studies during breastfeeding to prevent potential health risks for infants.

Distribution, sources, risks, and vitro DNA oxidative damage of PM2.5-bound atmospheric polycyclic aromatic hydrocarbons in Urumqi, NW China

Research has focused on the impacts of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere due to their potential carcinogenicity. In this study, we investigated the seasonal variation, sources, incremental lifetime cancer risks (ILCR_S), and vitro DNA oxidative damage of PAHs in Urumqi in NW China. A total of 72 atmospheric samples from Urumqi were collected over a year (September 2017-September 2018) and were analyzed for 16 PAHs that are specifically prioritized by the U.S Environmental Protection Agency (U·S EPA). The highest PAHs concentrations were in winter (1032.66 ng m^-3) and lowest in spring (146.00 ng m^-3). Middle molecular weight PAHs with four rings were the most abundant species (45.28-61.19% of the total). The results of the diagnostic ratio and positive matrix factorization inferred that the major sources of atmospheric PAHs in Urumqi were biomass burning, coking, and petrogenic sources (52.9%), traffic (30.1%), coal combustion (8.9%), and the plastics recycling industry (8.1%). ILCR_S assessment and Monte Carlo simulations suggested that for all age groups PAHs cancer risks were mainly associated with ingestion and dermal contact and inhalation was negligible. The plasmid scission assay results showed a positive dose-response relationship between PAHs concentrations and DNA damage rates, demonstrating that toxic PAHs was the primary cause for PM_2.5-induced DNA damage in the air of Urumqi.

World Trade Center Health Program: First Decade of Research

The terrorist attacks on 11 September 2001 placed nearly a half million people at increased risk of adverse health. Health effects research began shortly after and continues today, now mostly as a coordinated effort under the federally mandated World Trade Center (WTC) Health Program (WTCHP). Established in 2011, the WTCHP provides medical monitoring and treatment of covered health conditions for responders and survivors and maintains a research program aimed to improve the care and well-being of the affected population. By 2020, funds in excess of USD 127 M had been awarded for health effects research. This review describes research findings and provides an overview of the WTCHP and its future directions. The literature was systematically searched for relevant articles published from 11 September 2001 through 30 June 2020. Synthesis was limited to broad categories of mental health, cancer, respiratory disease, vulnerable populations, and emerging conditions. In total, 944 WTC articles were published, including peer-reviewed articles funded by the WTCHP (n = 291) and other sources. Research has focused on characterizing the burden and etiology of WTC-related health conditions. As the program moves forward, translational research that directly enhances the care of individuals with chronic mental and physical health conditions is needed.

The association between prenatal exposure to polycyclic aromatic hydrocarbons and birth weight: A meta-analysis

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are a kind of endocrine disruptors, which can enter human body by the inhalation of PAH-containing matter and the ingestion of PAH-containing foodstuffs. Studies showed that PAHs can cross the placental barrier and might cause adverse effects on the fetus.

OBJECTIVES

This meta-analysis aimed to estimate the associations between prenatal exposure to PAHs and birth weight.

METHODS

Articles published in English until May 8, 2020 and reported the effects of prenatal exposure to PAHs on birth weight were searched in multiple electronic databases including PubMed, the Web of Science, EMBASE and the Cochrane Library. The included studies were divided into three groups in accordance with the measurement of PAHs exposure. Then coefficient was extracted, conversed and synthesized by random-effects meta-analysis. And risk of bias was assessed for each study.

RESULTS

A total of 3488 citations were searched and only 11 studies were included finally after double assessment. We found that there were no association between PAH-DNA adducts in cord blood (low/high) (OR: 1.0, 95%CI: 0.97, 1.03), 1-hydroxy pyrene (1-HP) concentration in maternal urine (OR: 1.0, 95%CI: 0.97, 1.03) and prenatal maternal airborne PAHs exposure (OR: 0.97, 95%CI: 0.93, 1.01) and birth weight. However, we observed ethnicity may change the effects of PAHs exposure on birth weight.

CONCLUSIONS

There is no significant relationship between prenatal exposure to PAHs and birth weight in our meta-analysis. Further studies are still needed for determining the effects of prenatal PAHs exposure on birth weight.

Maternal air pollution exposure and congenital heart defects in offspring: A systematic review and meta-analysis

BACKGROUND

Congenital heart defects (CHDs) has a multifactorial causation with a strong genetic component and many environmental triggers. Emerging body of empirical studies suggest that air pollution is an important contributor to the development of CHDs, however, there still remains some controversy over the current evidence, and to the authors' knowledge, no studies have reviewed the most recent evidence.

OBJECTIVES

We performed a systematic review and meta-analysis of epidemiological literature to investigate the relationship between maternal air pollution exposure and CHDs risk in offspring. The presence of heterogeneity and publication bias across available studies were also examined.

METHODS

An extensive literature search of epidemiological studies pertaining to air pollution and CHDs, published in English language, until August 1, 2019 was conducted. Summary risk estimates of pollution-outcome combinations were calculated for i) risk per specific increment of concentration and ii) risk at high versus low exposure level in each study using fixed-effect model or random-effects model.

RESULTS

A total of 26 studies were finally included. In the meta-analyses, high versus low carbon monoxide (CO) exposure was associated with an increased risk of tetralogy of Fallot [odds ratio (OR) = 1.21, 95% confidence interval (CI): 1.04-1.41], yet particulate matter ≤ 5 μm (PM_2.5) exposure was marginally associated with it. Increased risk of atrial septal defects (ASDs) was found for each 10 μg/m³ and 10 ppb increment in particulate matter ≤ 10 μm (PM₁₀) and ozone (O₃) exposure, respectively (OR = 1.04, 95% CI: 1.00-1.09; OR = 1.09, 95% CI: 1.02-1.17). Categorical nitrogen dioxide (NO₂) exposure was associated with an increased risk of coarctation of the aorta (OR for high versus low = 1.14, 95% CI: 1.02-1.26). Analyses for other combinations yielded none statistically significant associations. Sensitive analyses showed similar findings.

CONCLUSIONS

The summary effect estimates from this study suggest statistically significant associations between increased risk of specific CHDs subtypes and PM_2.5, PM₁₀, NO₂, CO, and O₃ exposures. Further studies, especially conducted in developing countries, with improvements in exposure assessing, outcome harmonizing, and mechanistic understanding are needed to elaborate the suggestive associations.

Polycyclic Aromatic Hydrocarbons in Foods: A Critical Review

Objective:

Polycyclic aromatic hydrocarbons (PAHs) are well researched chemicals in foods that have been found to exhibit mutagenic and carcinogenic potentials. This study examined available literature on polycyclic aromatic hydrocarbons in foods, sources, effects and remediation.

Methods:

Available literature on polycyclic aromatic hydrocarbons in foods, sources, effects and remediation was critically reviewed.

Results:

The review showed that carcinogenicity of PAHs varies from the potent to moderately carcinogenic PAHs which include 3-methylcholanthrene, Benzo[a]pyrene, dibenz[a,h]anthracene, 5-methylchrysene, and dibenz[a,j]anthracene, whereas benzo[e]pyrene, dibenz[a,c]anthracene, chrysene, benzo[c]phenanthrene and fluoranthene are relatively weak or inactive carcinogens. Cooking processes have been found to be a major source of PAHs in foods. Although, PAHs can also be formed during curing and processing of raw food prior to cooking, several researchers in recent years have shown that the major dietary sources of PAHs are fish and meat especially where there is high consumption of meat cooked over an open flame. Several procedures and methods have been developed recently to assess and detect PAHs in foods and more recently, bio-monitoring procedures have also been developed to assess human exposure to PAHs. Numerous organizations such as the United States Environmental Protection Agency (U.S. EPA), the International Agency for Research on Cancer (IACR), the Scientific Committee on Food (SCF), the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the International Programme on Chemical Safety (IPCS), and the European Food Safety Authority (EFSA) have been involved in evaluating the occurrence and toxicity of PAHs.

Conclusion:

Conclusively, taking into consideration the sources of PAHs generation, adequate process and quality control of the processed foods could be a veritable mean to reduce PAHs ingestion in foods.

Railway-Associated Attractants as Potential Contaminants for Wildlife

Grizzly bears (Ursus arctos) appear to be attracted to natural and anthropogenic forage along railways, which may increase collision vulnerability, but also potentially causes exposure to contaminants associated with railway infrastructure. We assessed contaminant exposure for a vulnerable population of grizzly bears in the Canadian Rocky Mountains by determining if (1) dandelions (Taraxacum officinale) growing adjacent to a railway and grain spilled from hopper cars contain heavy metals, polycyclic aromatic hydrocarbons (PAHs), and mycotoxins and (2) metal concentrations from hair samples of individual bears correlates with use of the railway or other anthropogenic features. We used principle components analysis to represent 10 heavy metals and 16 PAHs and then compared their concentrations in railway-associated sources of grain and dandelions to reference samples that we purchased (grain) or sampled from nearby sites (dandelions). We also measured metal concentrations in the hair of bears that were captured and fitted with GPS collars. We found significantly higher concentrations in railway-associated samples of dandelion and grain for both metals (particularly lead, iron, and chromium), and the sum of 16 PAHs. Several metals and PAHs in railway-associated samples exceeded regulatory standards for soil or animal feed. Mycotoxins were detectable in grain samples, but occurred well below permissible standards. Metal concentrations in bear hair were not predicted by railway use, but higher metal concentrations occurred in male bears and two individuals that used ski hills during fall. As mitigation to reduce wildlife exposure to contaminants, particularly in protected areas, we encourage removal of railway grain deposits, regular maintenance of railway infrastructure, such as lubricating stations, and investigation of contaminants associated with other human infrastructures, such as ski hills.

Urinary monohydroxylated polycyclic aromatic hydrocarbons in primiparas from Shenzhen, South China: Levels, risk factors, and oxidative stress

The main objectives of the present study were to investigate urinary monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) in 77 primiparas who live in Shenzhen, Guangdong Province, China, and their association with 8-hydroxy-2'-deoxyguanosine (8-OHdG) and human health risks. High detection frequencies of OH-PAHs demonstrated the wide occurrence of chemicals in the human exposure to PAHs. The urinary concentrations of Σ₇OH-PAHs ranged from 1.37 to 45.5 ng/mL, and the median concentrations of 1-hydroxynaphthalene (1-OHN), 2-hydroxynaphthalene (2-OHN), 2-hydoxyfluorene (2-OHF), ΣOHPhe (the sum of 1-, 2+ 3-hydroxyphenanthrene), and 1-hydroxypyrene (1-OHP) were 3.00, 2.58, 0.31, 0.44, and 0.51 ng/mL, respectively. In the sum concentration of seven OH-PAHs, 1-OHN accounted for the largest proportion (43.7% of Σ₇OH-PAHs), followed by 2-OHN (37.1%), 2-OHF (4.94%), 1-OHP (8.01%), 1-OHPhe (4.79%), and 2+3-OHPhe (1.46%). The present results showed that vehicle exhaust and petrochemical emission are the main sources of PAHs in primiparas in Shenzhen, and inhalation is the most important exposure route. The living conditions have a significant influence on human exposure to PAHs. The concentrations of 8-OHdG were positively correlated with OH-PAH concentrations in urine because evidence suggested that urinary 8-OHdG levels can be considered as a biomarker of oxidative DNA damage. Hazard quotient was used to assess the human health risks from exposure to single compound, and hazard index was used to assess the cumulative risks of the compounds, which demonstrated that the exposure risks from PAHs in primiparas were relatively low.

Current situation of polycyclic aromatic hydrocarbons (PAH) in PM2.5 in a receptor site in Mexico City and estimation of carcinogenic PAH by combining non-real-time and real-time measurement techniques

Air pollution is a public health concern. Polycyclic aromatic hydrocarbons (PAH) are ubiquitous atmospheric pollutants contained in the atmospheric aerosol. PAH in particulate matter with diameters ≤2.5 µm (PM_2.5) represent a human health risk due to their toxic properties. In this study, PAH in PM_2.5 at a receptor site of Mexico City during the dry cold season were determined. The most abundant PAH (median, 10-90th percentile, pg m^-3) were benzo[ghi]perylene (467, 291-697), followed by pyrene (427, 218-642). A decrease around 40% in the carcinogenic PAH onto PM_2.5 was calculated with respect to the same PAH measured a decade ago, at the same receptor site, despite of increase in vehicle fleet. The PAH decrease trend agrees with the decrease trend of CO, NO and NO₂, released into the air by similar emission sources than PAH. Control emissions strategies implemented by local and federal authorities are discussed. PAH analyses were carried out by non-real-time and real-time methods. The PAH non-real-time method involved PM_2.5 sampling, sample treatment and gas chromatography-mass spectrometry analysis. The PAH real-time method involved the use of a photoelectric aerosol sensor (PAS). The PAH determination by non-real time method was selective and efficient, with recoveries between 75 ± 14% and 98 ± 26%. By combining non-real-time and real-time methodologies, multivariate regression models were obtained based on PAS response, NO₂ and wind speed to estimate PAH in PM_2.5 at low-cost (r² = 0.59 to r² = 0.89). Fossil fuel combustion from vehicles was the major source around the sampling site. Diagnostic ratios (DR) based on retene, chrysene, and triphenylene, suggested biomass burning emission sources. Photo-oxidation in sunny months was observed based on benzo[a]pyrene, benzo[ghi]perylene, benz[a]anthracene, indeno[1,2,3-cd]pyrene and black carbon. The correlation analyses suggested transport of PM_2.5, O₃, BC and SO₂ to the sampling site, and local emissions of PAH, NO and CO.

Comparative study of PM10-bound heavy metals and PAHs during six years in a Chinese megacity: Compositions, sources, and source-specific risks

To comparatively analyze source-specific risks of atmospheric particulate matter (PM), PM₁₀-bound polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) were synchronously detected in a megacity (Chengdu, China) from 2009 to 2016. Non-cancer risk (assessed by hazard quotient, HQ) of PAHs and HMs was within the acceptable level, while cancer risk (assessed by incremental life cancer risk (ILCR), R) of PAHs and HMs were 1.01 × 10^-4 and 9.40 × 10^-5 in DP and WP, which showed low risk. HMs dominated cancer (92.12%) and non-cancer (99.99%) risks. An advanced method named as joint source-specific risk assessment of HMs and PAHs (HP-SRA model) was developed to assess comprehensive source-specific risks. Gasoline combustion (contributed 9.6% of PM₁₀, 0.3% of HQ and 10.0% of R), diesel combustion (6.2% of PM₁₀, 0.2% of HQ and 10.7% of R), coal combustion (17.5% of PM₁₀, 1.8% of HQ and 13.4% of R), industrial source (9.1% of PM₁₀, 80.7% of HQ and 35.0% of R), crustal dust (28.1% of PM₁₀, 9.0% of HQ and 1.6% of R), nitrate (7.5% of PM₁₀, 1.1% of HQ and 6.2% of R) and sulphate & secondary organic carbon & adsorption (SSA, 19.6% of PM₁₀, 6.9% of HQ and 23.1% of R) were identified as main sources. For cancer risk, industrial sources and SSA posed the highest proportion. Higher levels of Co and Ni generated from industrial sources and Cr (Ⅵ), Cd and Ni absorbed in the SSA can result in high-risk contributions. Thus, controlling HMs levels in industrial emissions is essential to protecting human health.

Levels of polycyclic aromatic hydrocarbons in umbilical cord and risk of orofacial clefts

Polycyclic aromatic hydrocarbons (PAHs), which are ubiquitous in the environment, have been found to cause orofacial clefts (OFCs) in mouse model. However, evidence from the human study with markers of intrauterine exposure is absent. We explored the associations between the levels of sixteen PAHs in umbilical cord tissue and risk for OFCs using multivariable logistic models and Bayesian Kernel Machine Regression (BKMR). This case-control study included 89 OFC cases and 129 controls without congenital malformations. Concentrations of PAHs in umbilical cord tissue were detected using gas chromatography coupled to triple quadrupole tandem mass spectrometry. The median levels of ΣPAHs, Σlow molecular weight polycyclic aromatic hydrocarbons, and Σhigh molecular weight polycyclic aromatic hydrocarbons were all higher in cases of total OFCs and its subtypes than in controls, although the differences were not statistically significant. No statistical associations between levels of PAHs in umbilical cord tissue and risk for OFCs were observed in either multivariable logistic models or BKMR models. Maternal using a stove for heating and lower frequency of ventilation in the bedroom/living room, and consumptions of fresh green vegetables were positively correlated with levels of PAHs in umbilical cord. In conclusion, our results did not suggest that in utero exposure to PAHs were associated with the risk for OFCs, in estimating whether single effect of PAHs or joint effects of multiple PAHs.

Catechins Controlled Bioavailability of Benzo[a]pyrene (B[α]P) from the Gastrointestinal Tract to the Brain towards Reducing Brain Toxicity Using the In Vitro Bio-Mimic System Coupled with Sequential Co-Cultures

The aim of the current study was to examine the preventive effect of green tea catechins on the transport of Benzo[a]pyrene (B[α]P) into the brain using an in vitro bio-mimic system coupled with sequential co-cultures. When 72 μM of catechins was pre-treated, cellular cytotoxicity induced by IC₅₀ of B[α]P in human liver hepatocellular carcinoma (HepG2) and human brain microvascular endothelial cells (HBMECs) was reduced by 27% and 26%, respectively. The cellular integrity measured in HBMECs, which was exposed to IC₅₀ of B[α]P, slowly decreased. However, the pre-treatment of catechins retained cellular integrity that was 1.14 times higher than with the absence of catechins. Co-consumption of catechins reduced not only the bio-accessibility of B[α]P in digestive fluid, but it also decreased absorption of B[α]P in human intestinal epithelial cells (Caco-2) with a HepG2 co-culture system. It was found that approximately a two times lower amount of B[α]P was transported via the blood-brain barrier (BBB) compared to only the B[α]P intake. These results are taken in conjunction with each other support that catechins could be able to prevent brain toxicity induced by B[α]P in the human body by limiting the bio-availability of B[α]P.

Maternal Residential Proximity to Major Roadways and the Risk of Childhood Acute Leukemia: A Population-Based Case-Control Study in Texas, 1995-2011

Acute leukemia is the most common pediatric malignancy. Some studies suggest early-life exposures to air pollution increase risk of childhood leukemia. Therefore, we explored the association between maternal residential proximity to major roadways and risk of acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Information on cases with acute leukemia (n = 2030) was obtained for the period 1995-2011 from the Texas Cancer Registry. Birth certificate controls were frequency matched (10:1) on birth year (n = 20,300). Three residential proximity measures were assessed: (1) distance to nearest major roadway, (2) residence within 500 meters of a major roadway, and (3) roadway density. Multivariate logistic regression was used to generate adjusted odds ratios (aOR) and 95% confidence intervals (CI). Mothers who lived ≤500 meters to a major roadway were not more likely to have a child who developed ALL (OR = 1.03; 95% CI: 0.91-1.16) or AML (OR = 0.84; 95% CI: 0.64-1.11). Mothers who lived in areas characterized by high roadway density were not more likely to have children who developed ALL (OR = 1.06, 95% CI: 0.93-1.20) or AML (OR = 0.83, 95% CI: 0.61-1.13). Our results do not support the hypothesis that maternal proximity to major roadways is strongly associated with childhood acute leukemia. Future assessments evaluating the role of early-life exposure to environmental factors on acute leukemia risk should explore novel methods for directly measuring exposures during relevant periods of development.

Prenatal exposure to particulate matter and ozone: Bulky DNA adducts, plasma isoprostanes, allele risk variants, and neonate susceptibility in the Mexico City Metropolitan Area

Mexico City's Metropolitan Area (MCMA) includes Mexico City and 60 municipalities of the neighbor states. Inhabitants are exposed to emissions from over five million vehicles and stationary sources of air pollutants such as particulate matter (PM) and ozone. MCMA PM contains elemental carbon and organic carbon (OC). OCs include polycyclic aromatic hydrocarbons (PAHs), many of which induce mutagenic and carcinogenic DNA adducts. Gestational exposure to air pollution has been associated with increased risk of intrauterine growth restriction, preterm birth or low birth weight risk, and PAH-DNA adducts. These effects also depend on the presence of risk alleles. We investigated the presence of bulky PAH-DNA adducts, plasma 8-iso-PGF_2α (8-iso-prostaglandin F_2α ) and risk allele variants in neonates cord blood and their non-smoking mothers' leucocytes from families that were living in a highly polluted area during 2014-2015. The presence of adducts was significantly associated with both PM_2.5 and PM₁₀ levels, mainly during the last trimester of gestation in both neonates and mothers, while the last month of pregnancy was significant for the association between ozone levels and maternal plasma 8-iso-PGF_2α . Fetal CYP1B1*3 risk allele was associated with increased adduct levels in neonates while the presence of the maternal allele significantly reduced the levels of fetal adducts. Maternal NQO1*2 was associated with lower maternal levels of adducts. Our findings suggest the need to reduce actual PM limits in MCMA. We did not observe a clear association between PM and/or adduct levels and neonate weight, length, body mass index, Apgar or Capurro score. Environ. Mol. Mutagen. 60:428-442, 2019. © 2019 Wiley Periodicals, Inc.