Polycyclic aromatic hydrocarbon residues in human milk, placenta, and umbilical cord blood in Beijing, China

Salt assisted liquid-liquid extraction combined with dispersive liquid-liquid microextraction for the determination of 24 regulated polycyclic aromatic hydrocarbons in human serum

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants of great concern due to their carcinogenicity and mutagenicity. Their determination in human serum, particularly in at-risk populations, is necessary but difficult because they are distributed over a wide range of polarity and are present at trace level. A new method combining salting-out assisted liquid-liquid extraction (SALLE) and dispersive liquid-liquid microextraction with solidification of floating organic drop (DLLME-SFO) adapted to a reduced volume of sample (100 µl) was developed to determine 24 PAHs in human serum. Some key parameters of DLLME-SFO (volume of extraction solvent, ratio of extraction/dispersive solvent volumes, and salt addition) were first studied by applying it to spiked pure water. For its application to serum, a sample treatment step involving SALLE was optimized in terms of nature and content of salts and applied upstream of DLLME-SFO. It was applied to the extraction of 24 regulated PAHs from spiked serum followed by an analysis by liquid chromatography coupled with UV and fluorescence detection. The extraction recoveries ranged from 48.2 and 116.0 % (relative standard deviations: 2.0-14.6 %, n=5-9), leading to limits of quantification of PAHs in human serum from 0.04 to 1.03 µg/L using fluorescence detection and from 10 to 40 µg/L using UV detection. This final method combining SALLE and DLLME-SFO showed numerous advantages such as no evaporation step, high efficiency and low solvent-consumption and will be useful for monitoring PAHs in low volumes of serum.

Screening for compounds with bioaccumulation potential in breast milk using their retention behavior in two-dimensional gas chromatography

Discovery of emerging pollutants in breast milk will be helpful for understanding the hazards to human health. However, it is difficult to identify key compounds among thousands present in complex samples. In this study, a method for screening compounds with bioaccumulation potential was developed. The method can decrease the number of compounds needing structural identification because the partitioning properties of bioaccumulative compounds can be mapped onto GC×GC chromatograms through their retention behaviors. Twenty pooled samples from seven provinces in China were analyzed. 1,286 compounds with bioaccumulation potential were selected from over 3,000 compounds. Sixty-two compounds, including aromatic compounds, phthalates, and phenolics etc., were identified with a high level of confidence and then quantified. Among them, twenty-seven compounds were found for the first time in breast milk. Three phthalate plasticizers and two phenolic antioxidants were found in significantly higher concentrations than other compounds. A toxicological priority index approach was applied to prioritize the compounds considering their concentrations, detection frequencies and eight toxic effects. The prioritization indicated that 13 compounds, including bis(2-ethylhexyl) phthalate, dibutyl phthalate, 1,3-di-tert-butylbenzene, phenanthrene, 2,6-di-tert-butyl-1,4-benzoquinone, 2,4-di-tert-butylphenol, and others, showed higher health risks. Meanwhile, some compounds with high risk for a particular toxic effect, such as benzothiazole and geranylacetone, were still noteworthy. This study is important for assessing the risks of human exposure to organic compounds.

Phenanthrene-induced hyperuricemia with intestinal barrier damage and the protective role of theabrownin: Modulation by gut microbiota-mediated bile acid metabolism

Hyperuricemia is prevalent globally and potentially linked to environmental pollution. As a typical persistent organic pollutant, phenanthrene (Phe) poses threats to human health through biomagnification. Although studies have reported Phe-induced toxicities to multiple organs, its impact on uric acid (UA) metabolism remains unclear. In this study, data mining on NHANES 2001-2016 indicated a positive correlation between Phe exposure and the occurrence of hyperuricemia in population. Subsequently, adolescent Balb/c male mice were orally exposed to Phe at a dosage of 10 mg/kg bw every second day for 7 weeks, resulting in dysfunction of intestinal UA excretion and disruption of the intestinal barrier. Utilizing intestinal organoids, 16S rRNA sequencing of gut microbiota, and targeted metabolomic analysis, we further revealed that an imbalance in bile acid metabolism derived from gut microbiota might mediate the intestinal barrier damage. Additionally, the tea extract theabrownin (TB) effectively improved Phe-induced hyperuricemia and intestinal dysfunction at a dose of 320 mg/kg bw per day. In conclusion, this study demonstrates that Phe exposure is positively associated with hyperuricemia and intestinal damage, which provides new insights into the toxic effects induced by Phe. Furthermore, the present study proposes that supplementation with TB would be a healthy and effective improvement strategy for patients with hyperuricemia and intestinal injury caused by environmental factors.

Induction of insulin resistance in female mice due to prolonged phenanthrene exposure: unveiling the low-dose effect and potential mechanisms

Phenanthrene (Phe) is a commonly occurring polycyclic aromatic hydrocarbon (PAH) found in various food sources and drinking water. Previous studies have shown that long-term exposure to Phe in male mice leads to insulin resistance in a dose-dependent manner. However, the effect of Phe on glucose homeostasis in female mice remains unknown. To address this knowledge gap, female Kunming mice were exposed to Phe through their drinking water at concentrations of 0.05, 0.5, and 5 ng/mL. After 270 d of exposure, we surprisingly discovered a low-dose effect of Phe on insulin resistance in female mice, which differed from the effect observed in male mice and showed sexual dimorphism. Specifically, insulin resistance was only observed in the 0.05 ng/mL treatment, and this low-dose effect was also reflected in the concentration of Phe in white adipose tissue (WAT). Differences in metabolic enzyme activities in the liver may potentially explain this effect. The observed sexual dimorphism in Phe exposure could be attributed to variations in estrogen (E2) level and estrogen receptor beta (ERβ) expression in WAT. These findings highlight the association between environmental factors and the development of insulin resistance, emphasizing the pathogenic effect of even low doses of Phe. Moreover, sex dependent-effect should be given more attention when studying the toxic effects of environmental pollutants.

Maternal exposure to polycyclic aromatic hydrocarbons during pregnancy and timing of pubertal onset in a longitudinal mother-child cohort in rural Bangladesh

BACKGROUND

In experimental studies, several polycyclic aromatic hydrocarbons (PAHs) have shown endocrine disrupting properties, but very few epidemiological studies have examined their impact on pubertal development and results have been heterogenous.

OBJECTIVE

To explore if maternal PAH exposure during pregnancy was associated with the offspring's timing of pubertal onset.

METHODS

We studied 582 mother-daughter dyads originating from a population-based cohort in a rural setting in Bangladesh. Maternal urinary samples, collected in early pregnancy (on average, gestational week 8), were analyzed for monohydroxylated metabolites of phenanthrene (1-OH-Phe, Σ2-,3-OH-Phe, and 4-OH-Phe), fluorene (Σ2-,3-OH-Flu), and pyrene (1-OH-Pyr) using liquid chromatography with tandem mass spectrometry (LC-MS/MS). The girls were interviewed on two separate occasions concerning date of menarche, as well as breast and pubic hair development according to Tanner. Associations were assessed using Kaplan-Meier analysis and multivariable-adjusted Cox proportional hazards regression or ordered logistic regression.

RESULTS

In early pregnancy, the mothers' median urinary concentrations of Σ1-,2-,3-,4-OH-Phe, Σ2-,3-OH-Flu, and 1-OH-Pyr were 3.25 ng/mL, 2.0 ng/mL, and 2.3 ng/mL respectively. At the second follow-up, 78 % of the girls had reached menarche, and the median age of menarche was 12.7 ± 0.81 years. Girls whose mothers belonged to the second and third quintiles of ΣOH-Phe metabolites had a higher rate of menarche, indicating a younger menarcheal age (HR 1.39; 95 % CI 1.04, 1.86, and HR 1.41; 95 % CI 1.05, 1.88, respectively), than girls of mothers in the lowest quintile. This trend was not observed in relation to either breast or pubic hair development. None of the other maternal urinary PAH metabolites or the sum of all thereof in early pregnancy were associated with age at menarche or pubertal stage.

CONCLUSIONS

Indications of non-monotonic associations of prenatal phenanthrene exposure with the daughters' age of menarche were found, warranting further investigation.

Presence of polycyclic aromatic hydrocarbons and persistent organochlorine pollutants in human Milk: Evaluating their levels, association with Total antioxidant capacity, and risk assessment

Breastfeeding provides numerous health benefits for both infants and mothers, promoting optimal growth and development while offering protection against various illnesses and diseases. This study investigated the levels of polychlorinated biphenyls (PCB), organochlorine pesticides (OCP) and polycyclic aromatic hydrocarbons (PAH) in human milk sampled in Zadar (Croatia). The primary objectives were twofold: firstly, to evaluate the individual impact of each compound on the total antioxidant capacity (TAC) value, and secondly, to assess associated health risks. Notably, this study presents pioneering and preliminary insights into PAH levels in Croatian human milk, contributing to the limited research on PAH in breast milk worldwide. PCB and OCP levels in Croatian human milk were found to be relatively lower compared to worldwide data. Conversely, PAH levels were comparatively higher, albeit with lower detection frequencies. A negative correlation was established between organic contaminant levels and antioxidative capacity, suggesting a potential link between higher antioxidative potential and lower organic contaminant levels. Diagnostic ratio pointed towards traffic emissions as the primary source of the detected PAH. The presence of PAH suggests potential health risk, underscoring the need for further in-depth investigation.

Biological sex differences in hepatic response to in utero dimethylbenz(a)anthracene exposure

Fetal hepatic dimethylbenz(a)anthracene (DMBA) biotransformation is not defined, thus, this study investigated whether the fetal liver metabolizes DMBA and differs with biological sex. KK.Cg-a/a (lean; n = 20) or KK.Cg-Ay/J (obese; n = 20) pregnant mice were exposed to corn oil (CT) or DMBA (1 mg/kg bw/day) by intraperitoneal injection (n = 10/treatment) from gestation day 7-14. Postnatal day 2 male or female offspring livers were collected. Total RNA (n = 6) and protein (n = 6) were analyzed via a PCR-based array or LC-MS/MS, respectively. The level of Mgst3 was lower (P < 0.05) in livers of female compared to male offspring. Furthermore, in utero DMBA exposure increased (P < 0.1) Cyp2c29 and Gpx3 levels (P < 0.05) in female offspring. In male offspring, the abundance of Ahr, Comt (P < 0.1), Alox5, and Asna1 (P < 0.05) decreased due to DMBA exposure. Female and male offspring had 34 and 21 hepatic proteins altered (P < 0.05) by in utero DMBA exposure, respectively. Opposing patterns for hepatic CD81 and KRT78 occurred, being decreased in females but increased in males, while YWHAG was decreased by DMBA exposure in both. Functional KEGG pathway analysis identified enrichment of 26 and 13 hepatic metabolic proteins in male and female offspring, respectively, due to in utero DMBA exposure. In silico transcription factor analysis of differentially expressed proteins predicted involvement of female NRF1 but male AHR. Thus, hepatic biological sex differences and capacity to respond to toxicants in utero are supported.

Chronic exposure to low levels of phenanthrene induces histological damage and carcinogenic risk in the uterus of female mice

Phenanthrene (Phe), a polycyclic aromatic hydrocarbon with low molecular weight, is detected in the environment at high frequency. To study the toxic effects of Phe on the uterine structure and function, female Kunming mice were exposed to Phe (0.05, 0.5, 5 ng/mL) for 270 days by drinking water. Pathological alterations and their action pathways were analyzed using immunohistochemical and biomolecular technology. Phe significantly increased the percentage of blood vessel area, the number of endometrial neutrophils (indicating the occurrence of inflammation), collagen deposition (indicating fibrosis), and the percentage of Ki-67-positive cells (indicating carcinogenesis) in the uterus. Transcriptome sequencing identified differentially expressed genes that were mainly enriched in some signaling pathways, including inflammation and carcinogenesis, suggesting a carcinogenic risk in the Phe-exposed uterus. Elevated serum estrogen levels and decreased progesterone levels exhibited a disturbance of steroid hormone balance, which might be related to uterine damage. Upregulated protein levels of uterine androgen receptor and estrogen receptor α were linked to the pathological effects. Most of the effects exhibited a nonmonotonic dose response, which might be attributed to the corresponding change in the serum levels of Phe. The results suggest that exposure to low levels of Phe could exert adverse effects on the uterus.

Parent and halogenated polycyclic aromatic hydrocarbons exposure in aluminum smelter workers: Serum levels, accumulation trends, and association with health indicators

Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (HPAHs) can be unintentionally formed and released during industrial thermal processes. However, information on internal exposure and health risks of PAHs and HPAHs for thermal industry workers is very limited. In this study, serum samples from 220 aluminum smelter workers in East China were analyzed, and the relationship between the levels of these pollutants and various health indicators was also assessed. The workers had markedly higher serum concentrations of PAHs and HPAHs than the controls. The serum concentrations of ∑13PAHs and ∑9HPAHs increased with increasing age and occupational exposure duration in male workers. A positive correlation was observed between the ∑13PAH and ∑9HPAH serum concentrations, and the concentration of ∑13PAHs was approximately 50 times higher than that of ∑9HPAHs. For benzo[a]pyrene equivalent (BaPeq)-based risk assessment, the contribution of PAHs and HPAHs to the risk was 80 % and 20 % in the workers. PAHs and HPAHs showed a positive association with pulmonary hypofunction, hypertension and abnormal electrocardiogram. This study indicates occupational exposure to these toxic pollutants remains a significant issue and provides evidence that elevated serum levels of ∑13PAHs and ∑9HPAHs may be associated with an increased risk of lung and cardiovascular diseases.

Polycyclic aromatic hydrocarbon (PAH) source identification and a maternal transfer case study in threatened killer whales (Orcinus orca) of British Columbia, Canada

The northeastern Pacific (NEP) Ocean spans the coast of British Columbia (Canada) and is impacted by anthropogenic activities including oil pipeline developments, maritime fossil fuel tanker traffic, industrial chemical effluents, agricultural and urban emissions in tandem with stormwater and wastewater discharges, and forest wildfires. Such events may expose surrounding marine environments to toxic polycyclic aromatic hydrocarbons (PAHs) and impact critical habitats of threatened killer whales (Orcinus orca). We analyzed skeletal muscle and liver samples from stranded Bigg's killer whales and endangered Southern Resident killer whales (SRKWs) for PAH contamination using LRMS. C3-phenanthrenes/anthracenes (mean: 632 ng/g lw), C4-dibenzothiophenes (mean: 334 ng/g lw), and C4-phenanthrenes/anthracenes (mean: 248 ng/g lw) presented the highest concentrations across all tissue samples. Diagnostic ratios indicated petrogenic-sourced contamination for SRKWs and pyrogenic-sourced burdens for Bigg's killer whales; differences between ecotypes may be attributed to habitat range, prey selection, and metabolism. A mother-fetus skeletal muscle pair provided evidence of PAH maternal transfer; low molecular weight compounds C3-fluorenes, dibenzothiophene, and naphthalene showed efficient and preferential exposure to the fetus. This indicates in-utero exposure of PAH-contamination to the fetus. Our results show that hydrocarbon-related anthropogenic activities are negatively impacting these top predators; preliminary data found here can be used to improve oil spill and other PAH pollution management and regulation efforts, and inform policy to conserve killer whale habitats in the NEP.

Gender-specific associations between mixture of polycyclic aromatic hydrocarbons and telomere length

Evidence shows the relationships of individual environmental PAHs by their urinary metabolites with relative telomere length (RTL), which may be affected by biological gender differences. Since plasma parent PAHs are not metabolized, it may reflect human exposure to PAHs more realistically in daily life. Thus, exploring joint associations between plasma parent PAHs and RTL is urgent, which may identify the major contributor to its adverse effect. In this study, 2577 participants were obtained from the Henan Rural Cohort. The level of PAHs in blood samples was detected by gas chromatography coupled with tandem mass spectrometry. RTL in blood samples was detected by quantitative polymerase chain reaction. Generalized linear models or quantile g-computation were performed to evaluate the associations between the individual or a mixture of PAHs and RTL. Results from generalized linear models showed that each unit increment in BghiP value corresponded to a 0.098 (95%CI: 0.067, 0.129) increment in RTL for men; each unit increment in BaP, BghiP and Flu value corresponded to a 0.041 (95%CI: 0.014, 0.068), 0.081 (95%CI: 0.055, 0.107) and 0.016 (95%CI: 0.005, 0.027) increment in RTL for women. Results from quantile-g computation revealed that each one-quantile increment in the mixture of 10 PAHs corresponded to a 0.057 (95%CI: 0.021, 0.094) and 0.047 (95%CI: 0.003, 0.091) increment in RTL values of women and men, but these associations were mainly ascribed to three PAHs for women (BaP, Flu and BghiP) and men (BaP, BghiP and Pyr), respectively. Similar results were found in smoking men and cooking women without smoking. Our study found that exposure to 10 PAHs mixture was positively associated with RTL across gender, mainly attributed to Flu, BaP and BghiP, implicating that gender-specific associations may be ascribed to tobacco and cooking smoke pollution. The findings provided clues for effective measures to control PAHs pollutants-related aging disease.Clinical trial registration The Henan Rural Cohort Study has been registered at the Chinese Clinical Trial Register (Registration number: ChiCTR-OOC-15006699). Date of registration: 06 July 2015. http://www.chictr.org.cn/showproj.aspx?proj=11375 .

Effects of polycyclic aromatic hydrocarbons (PAHs) on pregnancy, placenta, and placental trophoblasts

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants that are carcinogenic, mutagenic, endocrine-toxic, and immunotoxic. PAHs can be found in maternal and fetal blood and in the placenta during pregnancy. They may thus affect placental and fetal development. Therefore, the exposure levels and toxic effects of PAHs in the placenta deserve further study and discussion. This review aims to summarize current knowledge on the effects of PAHs and their metabolites on pregnancy and birth outcomes and on placental trophoblast cells. A growing number of epidemiological studies detected PAH-DNA adducts as well as the 16 high-priority PAHs in the human placenta and showed that placental PAH exposure is associated with adverse fetal outcomes. Trophoblasts are important cells in the placenta and are involved in placental development and function. In vitro studies have shown that exposure to either PAH mixtures, benzo(a)pyrene (BaP) or BaP metabolite benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) affected trophoblast cell viability, differentiation, migration, and invasion through various signaling pathways. Furthermore, similar effects of BPDE on trophoblast cells could also be observed in BaP-treated mouse models and were related to miscarriage. Although the current data show that PAHs may affect placental trophoblast cells and pregnancy outcomes, further studies (population studies, in vitro studies, and animal studies) are necessary to show the specific effects of different PAHs on placental trophoblasts and pregnancy outcomes.

Evaluation of polycyclic aromatic hydrocarbons in sediments of Balsas River Mouth, Pacific Coast, Mexico: Sources, risks, and genotoxicity

Polycyclic aromatic hydrocarbons (PAHs) were assessed in sediments (n = 7) collected from the mouth of the Balsas River, Pacific Coast, Mexico. The total PAH levels ranged between 142.1 and 3944.07 μg kg^-1 in the summer and 137.65-3967.38 μg kg^-1 in the winter, probably reflecting the anthropogenic activities of the region. Calculation of the four analytical ratios of [Anthracene/(Anthracene + Phenanthrene)]: [Fluoranthene/(Fluoranthene + Pyrene)], [Fluoranthene/Pyrene: Fluoranthene/(Fluoranthene + Pyrene)], [Indeno [123-cd]Pyrene/(Indeno [123-cd]Pyrene + Benzo [ghi]Perylene)]: [Benzo [a]anthracene/(Benzo [a]Anthracene + Chrysene)], and [Anthracene/Phenanthrene]: [Fluoranthene/(Fluoranthene + Pyrene)] revealed a mixed PAH source, from petroleum and biomass combustion. Significant statistical correlations (r² = 0.90) between the 4 and 5 ringed PAHs denote that adsorption is the principal mechanism for accumulation in sedimentary archives. Ecotoxicological indices (Mean Effect Range Medium Quotient and Mean Probable Effect Level Quotient) indicated moderate pollution with adverse biological impacts on ambient benthonic organisms. The calculations of Toxicity Equivalent Quotient and Mutagen Equivalent Quotient values proposed that the region is highly polluted by mutagenic and carcinogenic PAH compounds. The genotoxic evaluation of Lutjanus guttatus (Spotted rose snapper) presented significant DNA damage and discrepancies in Ethoxyresorufin-O-Deethylase activity. Based on the toxicological and genotoxicological evaluation of PAHs in sediments, the region was observed to be largely impacted from biological damage.

Research progress in human biological monitoring of aromatic hydrocarbon with emphasis on the analytical technology of biomarkers

Aromatic hydrocarbons are unsaturated compounds containing carbon and hydrogen that form single aromatic ring, or double, triple, or multiple fused rings. This review focuses on the research progress of aromatic hydrocarbons represented by polycyclic aromatic hydrocarbons (including halogenated polycyclic aromatic hydrocarbons), benzene and its derivatives including toluene, ethylbenzene, xylenes (o-, m- and p-), styrene, nitrobenzene, and aniline. Due to the toxicity, widespread coexistence, and persistence of aromatic hydrocarbons in the environment, accurate assessment of exposure to aromatic hydrocarbons is essential to protect human health. The effects of aromatic hydrocarbons on human health are mainly derived from three aspects: different routes of exposure, the duration and relative toxicity of aromatic hydrocarbons, and the concentration of aromatic hydrocarbons which should be below the biological exposure limit. Therefore, this review discusses the primary exposure routes, toxic effects on humans, and key populations, in particular. This review briefly summarizes the different biomarker indicators of main aromatic hydrocarbons in urine, since most aromatic hydrocarbon metabolites are excreted via urine, which is more feasible, convenient, and non-invasive. In this review, the pretreatment and analytical techniques are compiled systematically for the qualitative and quantitative assessments of aromatic hydrocarbons metabolites such as gas chromatography and high-performance liquid chromatography with multiple detectors. This review aims to identify and monitor the co-exposure of aromatic hydrocarbons that provides a basis for the formulation of corresponding health risk control measures and guide the adjustment of the exposure dose of pollutants to the population.

Benzo(a)pyrene and Cerium Dioxide Nanoparticles in Co-Exposure Impair Human Trophoblast Cell Stress Signaling

Human placenta is a multifunctional interface between maternal and fetal blood. Studying the impact of pollutants on this organ is crucial because many xenobiotics in maternal blood can accumulate in placental cells or pass into the fetal circulation. Benzo(a)pyrene (BaP) and cerium dioxide nanoparticles (CeO2 NP), which share the same emission sources, are found in ambient air pollution and also in maternal blood. The aim of the study was to depict the main signaling pathways modulated after exposure to BaP or CeO2 NP vs. co-exposure on both chorionic villi explants and villous cytotrophoblasts isolated from human term placenta. At nontoxic doses of pollutants, BaP is bioactivated by AhR xenobiotic metabolizing enzymes, leading to DNA damage with an increase in γ-H2AX, the stabilization of stress transcription factor p53, and the induction of its target p21. These effects are reproduced in co-exposure with CeO2 NP, except for the increase in γ-H2AX, which suggests a modulation of the genotoxic effect of BaP by CeO2 NP. Moreover, CeO2 NP in individual and co-exposure lead to a decrease in Prx-SO3, suggesting an antioxidant effect. This study is the first to identify the signaling pathways modulated after co-exposure to these two pollutants, which are common in the environment.

Microbead-Beating Extraction of Polycyclic Aromatic Compounds from Seabird Plasma and Whole Blood

Seabirds are widely regarded as an invaluable bioindicator of environmental health. Matrices including eggs and feathers have been used as non-lethal means to assess contaminant burdens. We have developed a new approach for extraction of polycyclic aromatic compounds (PACs) from seabird plasma and serum based on automated microbead-beating homogenization and extraction. Commercially available bovine serum and plasma were purposely fortified with a suite of PACs separately at three dosing levels, placed inside a custom-made stainless-steel tube containing ceramic microbeads, and subjected to an extraction process using a Precellys tissue homogenizer. Tubes were shaken forcefully in three-dimensions, facilitating high mass-transfer of PACs from the matrix into the hexane extraction solvent. The accuracy of the method ranged from 55 to 120% and limits of detection and quantitation ranged from 0.1 to 8 and 0.2 to 27 pg/μL, respectively. The method exhibited good repeatability with both inter- and intra-day repeatability < 30%. The developed method represents an effective and efficient approach to extraction of PACs from important biological matrices.

Prenatal exposure to polycyclic aromatic hydrocarbons is not associated with behavior problems in preschool and early school-aged children: A prospective multi-cohort study

BACKGROUND

Epidemiological study findings are inconsistent regarding associations between prenatal polycyclic aromatic hydrocarbon (PAH) exposures and childhood behavior. This study examined associations of prenatal PAH exposure with behavior at age 4-6 years in a large, diverse, multi-region prospective cohort. Secondary aims included examination of PAH mixtures and effect modification by child sex, breastfeeding, and child neighborhood opportunity.

METHODS

The ECHO PATHWAYS Consortium pooled 1118 mother-child dyads from three prospective pregnancy cohorts in six U.S. cities. Seven PAH metabolites were measured in prenatal urine. Child behavior was assessed at age 4-6 using the Total Problems score from the Child Behavior Checklist (CBCL). Neighborhood opportunity was assessed using the socioeconomic and educational scales of the Child Opportunity Index. Multivariable linear regression was used to estimate associations per 2-fold increase in each PAH metabolite, adjusted for demographic, prenatal, and maternal factors and using interaction terms for effect modifiers. Associations with PAH mixtures were estimated using Weighted Quantile Sum Regression (WQSR).

RESULTS

The sample was racially and sociodemographically diverse (38% Black, 49% White, 7% Other; household-adjusted income range $2651-$221,102). In fully adjusted models, each 2-fold increase in 2-hydroxynaphthalene was associated with a lower Total Problems score, contrary to hypotheses (b = -0.80, 95% CI = -1.51, -0.08). Associations were notable in boys (b = -1.10, 95% CI = -2.11, -0.08) and among children breastfed 6+ months (b = -1.31, 95% CI = -2.25, -0.37), although there was no statistically significant evidence for interaction by child sex, breastfeeding, or neighborhood child opportunity. Associations were null for other PAH metabolites; there was no evidence of associations with PAH mixtures from WQSR.

CONCLUSION

In this large, well-characterized, prospective study of mother-child pairs, prenatal PAH exposure was not associated with child behavior problems. Future studies characterizing the magnitude of prenatal PAH exposure and studies in older childhood are needed.

Association between fetal exposure to polycyclic aromatic hydrocarbons and low birth weight: a case-control study in Shenzhen, China

The potential hazards of polycyclic aromatic hydrocarbons (PAHs) on fetus development have raised widespread concerns in recent years, although current epidemiological findings are conflicting. The aim of this case-control study was to investigate the relationship between PAH concentrations in maternal serum and low birth weight (LBW). A questionnaire survey was conducted among 144 (72 pairs) neonates with normal or LBW and their mothers at four different hospitals in Shenzhen, China. Peripheral blood from primiparas and umbilical cord blood from neonates were collected. Concentrations of PAHs were determined by gas chromatography-mass spectrometry. The detection frequencies of PAHs were relatively higher in the peripheral blood samples, while levels of low molecular weight PAHs were greater than high molecular weight PAHs in both peripheral and umbilical cord blood samples. Phenanthrene was frequently detected in blood samples from the case and control groups. Logistic regression analysis showed that acenaphthene in peripheral blood was positively associated with LBW (p < 0.05). This study found a relationship between exposure to certain PAHs and LBW, although future studies are needed to confirm these results.

Long-term exposure to environmental levels of phenanthrene induces emaciation-thirst disease-like syndromes in female mice

Phenanthrene (Phe) is a polycyclic aromatic hydrocarbon widely present in foods and drinking water. To explore the detrimental effects of Phe on body metabolism, female Kunming mice were treated with Phe in drinking water at concentrations of 0.05, 0.5 and 5 ng/mL. After exposure for 270 d, the animals exhibited dose-dependent reduced body weight and increased water consumption. The dose-dependent accumulation of Phe in the brain decreased hypothalamic neuron numbers, upregulated hypothalamic expression of anaplastic lymphoma kinase, elevated norepinephrine levels in white adipose tissue (WAT) and further activated lipolysis in WAT, leading to a reduction in fat mass. Brown adipose tissue formation was reduced, accompanied by the inhibition of the bone morphogenetic protein signaling pathway. A simultaneous reduced serum levels of antidiuretic hormone (arginine vasopressin) might be one of the reasons for increased water consumption. The present results indicate an environmental etiology and prevention way for the development of emaciation-thirst disease.

Polycyclic aromatic hydrocarbons in breast milk of nursing mothers: Correlates with household fuel and cooking methods used in Uganda, East Africa

Maternal breast milk, which is a complete food for the infant's growth, development, and health, contains fats and lipids making it susceptible to accumulation of lipophilic compounds like polycyclic aromatic hydrocarbons (PAHs). This study aimed at analyzing correlates of measured levels of PAHs in breast milk of nursing mothers to frequently used household fuels and cooking methods in Uganda, and estimate the potential health risks of PAHs to infants through breastfeeding. Sixty breast milk samples were collected from healthy and non-smoking mothers who had lived in Kampala capital city (urban area) and Nakaseke district (rural area) for at least five years. Sample extracts were analyzed for PAHs using a gas chromatograph coupled with a triple quadrupole mass spectrometer. ∑₁₃PAHs in samples from Kampala ranged from 3.44 to 696 ng/g lw while those from Nakaseke ranged from 0.84 to 87.9 ng/g lw. PAHs with 2-3 rings were more abundant in the samples than PAHs with 4-6 rings. At least 33 % of the variance in the levels of ∑₁₃PAHs in the breast milk samples was attributable to the fuel type and cooking methods used. Nursing mothers who used charcoal for cooking accumulated higher levels of ∑₁₃PAHs in their breast milk samples compared to those who used firewood. Levels of ∑₁₃PAHs in breast milk of mothers increased depending on the cooking methods used in the order; boiling< grilling< deep-frying. In all samples, hazard quotients for PAHs were <1 and estimated incremental cancer risks were all between 10^-6 and 10^-4, indicating that the health risks to infants due to the ingestion of PAHs in breast milk was tolerable. Further studies with large datasets on PAHs and their derivatives and, larger samples sizes are needed to confirm these findings.

Metagenomic Analysis of Microbial Alliances for Efficient Degradation of PHE: Microbial Community Structure and Reconstruction of Metabolic Network

Polycyclic aromatic hydrocarbons are a widespread organic pollutant worldwide. In this study, a highly efficient phenanthrene (PHE)-degrading microbial community was enriched from oil extraction soil, which could degrade 500 mg/L PHE within 4 days. Using 16S rRNA sequencing, the dominant bacteria in this community at the phylum level were found to be Proteobacteria, Actinobacteria, and Firmicutes. Metagenomic annotation of genes revealed the metabolic pathways and the contribution of different bacteria to the degradation process. Pseudomonadaceae contributed multiple functional genes in the degradation process. This study revealed the functional genes, metabolic pathways, and microbial interactions of the microbial community, which are expected to provide guidance for practical management.

Exposure to phenanthrene affects oocyte meiosis by inducing mitochondrial dysfunction and endoplasmic reticulum stress

OBJECTIVES

Phenanthrene (PHE) is one of the most abundant polycyclic aromatic hydrocarbons (PAHs), which is a widespread environmental contaminant. Various studies showed that PHE has adverse impacts on animals and human health. It has been shown that PHE exposure induced follicular atresia and endocrine dyscrasia in female mice. However, the potential mechanism regarding how PHE affects female reproductive system especially the oocyte quality has not been elucidated.

METHODS AND RESULTS

In this study, we set up PHE exposure model and found that PHE exposure compromised oocytes maturation competence by inhibiting spindle assembly and chromosomes alignment. Moreover, PHE exposure induced mitochondrial dysfunction and endoplasmic reticulum (ER) stress, leading to increased reactive oxygen species (ROS) and aberrant calcium levels in cytoplasm, eventually induced oxidative stress and DNA damage in oocytes. Furthermore, we found that oral administration of PHE caused the occurrence of oxidative stress and apoptosis in female ovary. In addition, the oocyte exhibited aberrant spindle morphology and failure of actin cap formation in metaphase II oocytes.

CONCLUSIONS

Taken together, our study demonstrated that mitochondrial dysfunction and ER stress-induced oxidative stress and DNA damage are the major cause of poor oocyte quality after PHE exposure.

Parent and Halogenated Polycyclic Aromatic Hydrocarbons in the Serum of Coal-Fired Power Plant Workers: Levels, Sex Differences, Accumulation Trends, and Risks

Workers in coal-fired power plants are at a high risk of exposure to polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (HPAHs), yet no studies have investigated such exposure of HPAHs. In this study, 12 PAHs and 8 chlorinated PAHs, but no brominated PAHs, were detected in >80% of serum samples from workers of a coal-fired power plant in eastern China. Serum HPAH concentrations were higher in plant workers (16-273 ng/g lipid) than in people without occupational exposure (12-51 ng/g lipid), and serum PAH and HPAH concentrations both in male and female workers were positively correlated with the occupational exposure duration, with an estimated doubling time of 11-17 years. Correlations were found between concentrations of ∑₈HPAHs and ∑₁₂PAHs but not between 7-chlorobenz[a]anthracene (7-ClBaA) and 1-chloropyrene (1-ClPyr) and their respective parent PAHs. In males, total concentrations of PAHs and HPAHs were positively correlated with pulmonary hypofunction and hypertension but not with abnormal electrocardiogram. The benzo[a]pyrene equivalents ratio of ∑₈HPAHs/∑₁₂PAHs was 0.3 ± 0.1. Among the HPAHs in the serum, 9-chlorophenanthrene, 7-ClBaA, and 1-ClPyr showed high health risks. This study is the first report on HPAH exposure in coal-fired power plant workers and provides new evidence on the health risks of PAHs and HPAHs in humans.

Live in same region, respond differently: Canine and human response to pollutants in placental accumulation

Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) are endocrine-disrupting chemicals (EDCs). Their presence in the environment is particularly concerning in cases of fetal exposure, which is the most vulnerable period of life for both human and animals who share the same environment. Placenta, as a sample collected using noninvasive methods to screen EDCs, is a good indicator for potential fetal exposure. Although recent studies indicate that companion animal may correspond to human exposure, species-specific anatomo-morphological and metabolic differences are controversial. In this study, placenta samples of 60 women and 25 dogs living and giving birth within the same region were evaluated for the presence of PCB, OCP, PBDE, and PAH residues; where, socio-demographic factors were also assessed to identify the possible sources. Gas chromatography-mass spectrometry method was validated for the matrix, and among 45 screened and targeted pollutants, only 18 were found in human placentas. While the most frequently detected pollutants were DDTs, followed by PAHs and PCBs in decreasing order, the pollutants with the highest concentrations were PAHs, followed by PCBs and DDTs. Only five of the target contaminants were detected in the dog placentas. These results indicate that; as dogs have different bioaccumulation capacities and higher excretion rates than humans, the life-long effects of exposure to endocrine compound and possible consequences related to adverse health outcomes are expected to vary and concentrations cannot be directly correlated.

Joint association of polycyclic aromatic hydrocarbons and heavy metal exposure with pulmonary function in children and adolescents aged 6-19 years

Studies have reported associations between polycyclic aromatic hydrocarbon (PAH) or heavy metal (HM) exposure and respiratory diseases. However, evidence of their joint associations with pulmonary function, especially in children and adolescents aged 6-19 years, is lacking. We utilized cross-sectional data from 1,734 children and adolescents aged 6-19 years collected in the National Health and Nutrition Examination Survey 2007-2012 and analysed mixed PAH and mixed HM exposures and their joint association with pulmonary function by applying weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR). Multivariate linear regressions were carried out to determine the relationships between individual urinary PAH metabolites or blood HM levels and pulmonary function indices. We found that mixed PAHs and HMs were negatively related to forced expiratory volume in 1 s (FEV1) in subjects aged 6-12 years (all p values < 0.05). We found synergistic associations of PAH and HM exposure on pulmonary function impairment, mainly in children; lead (Pb) was the most damaging. In the analysis of individual PAH metabolites or HMs, Pb exposure was negatively associated with FEV1 values in all subgroups (all p values < 0.05). Thus, our findings indicate that increased PAH or HM exposure is associated with impairments to pulmonary function and that this association is more pronounced in children.

Insights into the hepatotoxicity of pyrene and 1-chloropyrene using an integrated approach of metabolomics and transcriptomics

The toxicity of pyrene (Pyr) and its chlorinated species have not be comprehensively and clearly elucidated. In this study, an integrated approach of metabolomics and transcriptomics were applied to evaluate the hepatotoxicity of Pyr and 1-chloropyrene (1-Cl-Pyr) at human exposure level, using human L02 hepatocytes. After 24 h exposure to Pyr and 1-Cl-Pyr at 5-500 nM, cell viability was not significantly changed. Transcriptomics results showed that exposure to Pyr and 1-Cl-Pyr at 5 and 50 nM obviously altered the gene expression profiles, but did not significantly induce the expression of genes strongly related to the activation of aryl hydrocarbon receptor (AhR), such as CYP1A1, CYP1B1, AHR, ARNT. Pyr and 1-Cl-Pyr both induced a notable metabolic perturbation to L02 cells. Glycerophospholipid metabolism was found to be the most significantly perturbed pathway after exposure to Pyr and 1-Cl-Pyr, indicating their potential damage to the cell membrane. The other significantly perturbed pathways were identified to be oxidative phosphorylation (OXPHOS), glycolysis, and fatty acid β oxidation, all of which are related to energy production. Exposure to Pyr at 5 and 50 nM induced the up-regulation of fatty acid β oxidation and OXPHOS. The similar result was observed after exposure to 5 nM 1-Cl-Pyr. In contrast, exposure to 50 nM 1-Cl-Pyr induced the down-regulation of OXPHOS by inhibiting the activity of complex I. The obtained results suggested that the modes of action of Pyr and 1-Cl-Pyr on energy production remarkably varied not only with molecular structure change but also with exposure concentration.

Prenatal exposure to a mixture of PAHs causes the dysfunction of islet cells in adult male mice: Association with type 1 diabetes mellitus

Polycyclic aromatic hydrocarbons (PAHs) have been detected throughout the human body. Whether exposure to PAHs is associated with the incidence of type 1 diabetes mellitus should be investigated. To this end, pregnant mice were exposed to mixed PAHs (5, 50, or 500 μg/kg) once every other day during gestation. The adult male offspring displayed impaired glucose tolerance and reduced serum levels of glucagon and insulin. Immunohistochemical staining revealed increased numbers of apoptotic β-cells and a reduced β-cell mass in these males. The downregulated expression of pancreatic estrogen receptor α, androgen receptor, and transcription factor PDX1 was responsible for impacting β-cell development. The relatively reduced α-cell area was associated with downregulated ARX expression. The transcription of Isn2 and Gcg in pancreatic tissue was downregulated, which indicated that the function of β-cells and α-cells was impaired. Methylation levels in the Isn2 promotor were significantly elevated in mice prenatally exposed to 500 µg/kg PAHs, which was consistent with the change in its mRNA levels. The number of macrophages infiltrating islets was significantly increased, indicating that prenatal PAH exposure might reduce islet cell numbers in an autoimmune manner. This study shows that prenatal exposure to PAHs may promote the pathogenesis of type 1 diabetes mellitus.

Gestational exposure to phenanthrene induces follicular atresia and endocrine dyscrasia in F1 adult female

Epidemiological investigations and animal studies demonstrate a significantly positive relationship between polycyclic aromatic hydrocarbons (PAHs) exposure and reproductive disorders. However, few researches are focused on the reproductive toxicity of low-molecular-weight PAHs (number of benzene ring ≤ 3) which occupy a large part of PAHs. Phenanthrene (Phe), a typical low-molecular-weight PAH, is one of the most abundant PAHs detected in foods. In the present study, oral treatment with Phe at a human exposure related level during gestation (60 μg/kg body weight every three days, six times in total) induced reproductive disorders in F1 adult female mice: the number of antral follicles (an immature stage of follicular development) were significantly increased, while the maturation of oocytes was inhibited and aggravated follicular atresia was observed; the serum levels of luteinizing hormone (LH), testosterone and estradiol were significantly reduced; the receptor of follicle-stimulating hormone (FSHR) and aromatase in the ovary were significantly upregulated; transcriptome analysis demonstrated that the phosphatidylinositol 3-kinase and protein kinase B (PI3K/Akt) signal pathway was upregulated, and the calcium signal pathway was disturbed, which probably accounts for the exacerbated atresia of the growing follicles and the excessive consumption of follicles. The reproductive toxicity of low-molecular-weight PAHs could not be neglected.

Recent advances in the development of healthier meat products

Meat products are an excellent source of high biological value proteins, in addition to the high content of minerals, vitamins, and bioactive compounds. However, meat products contain compounds that can cause a variety of adverse health effects and pose a serious health threat to humans. In this sense, this chapter will address recent strategies to assist in the development of healthier meat products. The main advances about the reduction of sodium and animal fat in meat products will be presented. In addition, strategies to make the lipid profile of meat products more nutritionally advantageous for human health will also be discussed. Finally, the reduction of substances of safety concern in meat products will be addressed, including phosphates, nitrites, polycyclic aromatic hydrocarbons, heterocyclic aromatic amines, as well as products from lipid and protein oxidation.

Prenatal exposure to polycyclic aromatic hydrocarbons and effects on neonatal anthropometric indices and thyroid-stimulating hormone in a Middle Eastern population

Prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) evokes extensive concerns regarding public health. Monitoring the pregnant women's exposure can be considered a suitable alternative to assess the fetus's exposure. This study aimed to monitor pregnant women's exposure (n = 126) to PAHs using a biomonitoring approach to evaluate effects on anthropometric indices and neonatal thyroid-stimulating hormone (TSH) in Shiraz, Iran. PAHs priority compounds were measured by gas chromatography-mass spectrometry (GC-MS) after separating blood serum and liquid-liquid extraction (LLE) method. Information on anthropometric indices, neonatal TSH levels, and data from the respondents was obtained from medical records and questionnaires. The mean PAHs concentrations ranged from 0.29 to 327.91 ng/g lipid. There was no significant difference between the measured PAHs in maternal serum at the seventh month and pregnancy termination except for ACY (p-Value<0.05). Regression analysis results showed a significant correlation (p-value<0.05) between exposure to passive smoke and total PAHs concentrations. There was no significant relationship between exposure to PAHs and weight, height, head circumference, and Apgar score of newborns. The results showed TSH decreased by 0.99 units as ACE increased per unit (β = -0.001). This study is the first to evaluate relationships between prenatal exposure to PAHs and effects on newborn health indicators, including TSH levels in a Middle Eastern population. Future studies are suggested to perform detailed assessments of PAHs intake sources, especially in vulnerable populations such as pregnant women and children.

The concentration of polycyclic aromatic hydrocarbons (PAHs) in mother milk: A global systematic review, meta-analysis and health risk assessment of infants

Background

Bio-monitoring of polycyclic aromatic hydrocarbons (PAHs) contaminants in mother milk is essential to keep mothers and infants healthy against potential risks. The current study assesses the concentration of PAHs in mother milk through a meta-analytic and systematic review approach.

Methods

All the published studies up to December 2020 regarding the concentrations of various PAHs in mother milk were searched throughout major international databases such as PubMed, Scopus, and Web of Science. Moreover, the possible carcinogenic and mutagenic risks to infants were evaluated based on the BaP (benzo[a]pyrenee) equivalent dose.

Results

According to the results of 13 articles included among 936 retrieved studies, the lowest and highest concentration of PAHs was (0.125 ng/g) and (76.36 ng/g) related to benz(a)anthracenem and 1-methylnaphthalene, respectively. The highest (9.830 ng/g) and lowest (0.009 ng/g) concentration of PAHs was related to Mexico and Japan, respectively. Besides, carcinogenetic and mutagenic risk assessment of the PAHs indicated that risk pattern was different across countries. It can be concluded that the consumption of mother milk is safe and does not pose a risk due to the ingestion of PAHs to the health of infant consumers.

In utero exposure to mixed PAHs causes heart mass reduction in adult male mice

Polycyclic aromatic hydrocarbons (PAHs) are a risk factor for the occurrence of cardiac diseases. The present study was conducted to investigate the influence of prenatal exposure to a mixed PAHs on heart and the underlying mechanism. Pregnant mice were orally administered with a mixture of 8 kinds of PAHs (0, 5, 50, 500 μg/kg body weight) once every 2 days for a total of 8 dosages. The mixed PAHs contained naphthalene, acenaphthylene, phenanthrene, fluoranthene, pyrene, benzo[a]pyrene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene at a weight ratio of 10: 10: 10: 10: 10: 1: 1: 1. The adult males, not females, showed significantly decreased heart/body weight ratio, which was attributed to the loss of cardiac fiber and the increase of cell apoptosis. The protein expression of transforming growth factor β1 and its downstream transcription factors, Smad3 and Smad4, was significantly downregulated, which caused the loss of cardiac fiber. The downregulated phosphatidylinositol 3-kinase and AKT led to increased expression of caspase3, caspase9, BAX and reduced expression of Bcl-2, which was responsible for the increased cell apoptosis. Different levels of aromatic hydrocarbon receptor and sex hormone receptors between males and females were associated with the distinct effect on heart.

Fetoplacental vasculature as a model to study human cardiovascular endocrine disruption

Increasing evidence has associated the exposure of endocrine-disrupting chemicals (EDCs) with the cardiovascular (CV) system. This exposure is particularly problematic in a sensitive window of development, pregnancy. Pregnancy exposome can affect the overall health of the pregnancy by dramatic changes in vascular physiology and endocrine activity, increasing maternal susceptibility. Moreover, fetoplacental vascular function is generally altered, increasing the risk of developing pregnancy complications (including cardiovascular diseases, CVD) and predisposing the foetus to adverse health risks later in life. Thus, our review summarizes the existing literature on exposures to EDCs during pregnancy and adverse maternal health outcomes, focusing on the human placenta, vein, and umbilical artery associated with pregnancy complications. The purpose of this review is to highlight the role of fetoplacental vasculature as a model for the study of human cardiovascular endocrine disruption. Therefore, we emphasize that the placenta, together with the umbilical arteries and veins, allows a better characterization of the pregnant woman's exposome. Consequently, it contributes to the protection of the mother and foetus against CV disorders in life.

Polycyclic aromatic hydrocarbons in 30 river ecosystems, Taiwan: Sources, and ecological and human health risks

Polycyclic aromatic hydrocarbons (PAHs) are diverse contaminants of global concern because of their ubiquity, toxicity, and carcinogenicity to many organisms, including humans. This study determines the distribution and sources of PAHs in sediments and fish from 30 major rivers in Taiwan, and the risks these PAHs pose to river ecosystems and human health. The total concentrations of 26 PAHs in sediments and fish were 0.016-7.44 mg/kg dw and 0.096-5.51 mg/kg ww, respectively. The PAH composition in sediments differed from that in fish, indicating that sediments may not be the major contributor of PAHs to fish. The accumulation of different PAH compounds in fish was species-specific, depending on the lipid content, living pattern, and trophic level of each fish species, and on the level of environmental contamination. The diagnostic ratios revealed that PAHs in the sediment primarily originated from pyrogenic sources, with some contribution from petrogenic sources. The contribution of each source varied with the sampling site and season. Several water and air quality variables were found to significantly correlate with PAH concentration in sediments and fish, suggesting that PAHs were mainly derived from wastewater discharge and combustion emissions. The 95th percentile risk quotient values suggested that PAHs in sediment from six rivers pose high ecotoxicological risks. The toxic equivalents of benzo[a]pyrene for 16 PAHs in fish were 12-108 μg/kg dw. A human risk assessment using the 95th percentile values of hazard quotient, hazard index, and margin of exposure revealed that the consumption of contaminated fish muscle poses no remarkable risk to human health. However, the 95th percentile carcinogenic risk values indicated that benzo[a]pyrene concentrations in some fish muscles may pose a carcinogenic risk. Benzo[a]pyrene risk management measures are, therefore, necessary.

Long-term exposure to environmental levels of phenanthrene disrupts spermatogenesis in male mice

Phenanthrene (Phe) is a tricyclic polycyclic aromatic hydrocarbon with high bioavailability under natural exposure. However, there are few studies on the reproductive toxicity of Phe in mammals. In this study, male Kunming mice were gavaged once every two days with Phe (5, 50, and 500 ng/kg) for 28 weeks. The accumulation levels of Phe in the testis were dose-dependently increased. Histopathological staining showed that Phe exposure reduced the number of spermatogonia, sperm and Sertoli cells. The percentage of testicular apoptotic cells was significantly increased, which was further verified by the upregulated BAX protein. The expression of the GDNF/PI3K/AKT signaling pathway was downregulated, which might suppress the self-renewal and differentiation of spermatogonial stem cells. Meanwhile, Phe exposure inhibited the expression of Sertoli cell markers (Fshr, WT1, Sox9) and the Leydig cell marker Cyp11a1, indicating damage to the function of Sertoli cells and Leydig cells. Serum estrogen and testicular estrogen receptor alpha were significantly upregulated, while androgen receptor expression was downregulated. These alterations might be responsible for impaired spermatogenesis. This study provides new insights for evaluating the reproductive toxicity and potential mechanisms of Phe in mammals.

Benzo[a]pyrene aggravates atopic dermatitis-like skin lesions in mice

Background: Benzo[a]pyrene (BaP) affects the immune system and causes mutagenic and carcinogenic effects. Purpose: We aimed to evaluate the effects of systemic exposure to BaP on mite allergen-induced atopic dermatitis (AD)-like skin lesions in mice. Methods: Mite allergen (Dermatophagoides pteronyssinus; Dp) was injected intradermally into the right ears of NC/Nga male mice on eight occasions every 2-3 days. Benzo[a]pyrene was administered intraperitoneally in the equivalent doses of 0, 2, 20, 200, or 2000 μg/kg/day, once a week on four occasions. Results: AD-like skin inflammation related to mite allergen worsened by BaP exposure at 2, 20 µg/kg/day doses; this was in parallel with eosinophil and mast cell infiltration and mast cell degranulation. A trend was also observed toward increased proinflammatory molecule expression, including macrophage inflammatory protein-1 alpha, interleukin (IL)-4, IL-13, and IL-18, in the ear tissue. However, 200 or 2000 µg/kg/day BaP attenuated the enhancing effects. In the regional lymph nodes, 2 µg/kg/day BaP with Dp enhanced antigen-presenting cell and T cell activation compared with Dp alone. Conclusions: This suggests that BaP exposure can aggravate Dp-induced AD-like skin lesions through T_H2-biased responses in the inflamed sites and the activation of regional lymph nodes. Therefore, BaP may be responsible for the recent increase in AD incidence.

Polycyclic Aromatic Hydrocarbons in Foods: Biological Effects, Legislation, Occurrence, Analytical Methods, and Strategies to Reduce Their Formation

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds comprised of carbon and hydrogen molecules in a cyclic arrangement. PAHs are associated with risks to human health, especially carcinogenesis. One form of exposure to these compounds is through ingestion of contaminated food, which can occur during preparation and processing involving high temperatures (e.g., grilling, smoking, toasting, roasting, and frying) as well as through PAHs present in the soil, air, and water (i.e., environmental pollution). Differently from changes caused by microbiological characteristics and lipid oxidation, consumers cannot sensorially perceive PAH contamination in food products, thereby hindering their ability to reject these foods. Herein, the occurrence and biological effects of PAHs were comprehensively explored, as well as analytical methods to monitor their levels, legislations, and strategies to reduce their generation in food products. This review updates the current knowledge and addresses recent regulation changes concerning the widespread PAHs contamination in several types of food, often surpassing the concentration limits deemed acceptable by current legislations. Therefore, effective measures involving different food processing strategies are needed to prevent and reduce PAHs contamination, thereby decreasing human exposure and detrimental health effects. Furthermore, gaps in literature have been addressed to provide a basis for future studies.

In utero exposure to phenanthrene induced islet cell dysfunction in adult mice: Sex differences in the effects and potential causes

Epidemiological studies show that the burden of polycyclic aromatic hydrocarbons in human body is associated with the occurrence of insulin resistance and diabetes. In the present study, pregnant mice were exposed to phenanthrene (Phe) at doses of 0, 60 and 600 μg/kg body weight of by gavage once every 3 days. The female F1 mice at 120 days of age showed no change in their fasting glucose levels (FGLs) but exhibited significantly decreased homeostasis model assessment (HOMA) β-cell (49% and 43%) and significantly downregulated pancreatic proinsulin gene (ins2) transcription. The downregulation of transcription factors, such as PDX1, PAX4 and FGF21, indicated impaired development and function of β-cells. The significantly reduced α-cell mass in 60 and 600 μg/kg groups, and the significantly downregulated expression of proglucagon gene gcg and ARX in the 600 μg/kg group suggested that the development and function of α-cells had been impacted. The males exhibited significantly increased FGLs (1.14- and 1.15-fold) in Phe exposed treatments and significantly elevated HOMA β-cell (3.15-fold) in the 600 μg/kg group. Upregulated ins2 transcription and FGF21 protein in male mice prenatally exposed to 600 μg/kg Phe suggested that these animals appeared compensatory enhancement in β-cell function. The reduced serum estradiol levels and downregulated pancreatic estrogen receptor α and β were responsible for the dysfunction of β-cells in the females. In the males, the significantly elevated androgen levels in the 600 μg/kg group might be related to the upregulated ins2 transcription, and the increased expression of pancreatic FGF21 further demonstrated the enhancement of β-cell potential. The results will be helpful for assessing the risk of developing diabetes in adulthood after prenatal exposure to phenanthrene.

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.

Maternal exposure to phenanthrene during gestation disturbs glucose homeostasis in adult mouse offspring

Epidemiological studies have indicated that polycyclic aromatic hydrocarbons were related to diabetes and insulin resistance. However, studies in mammals on the development of diabetes caused by polycyclic aromatic hydrocarbons are lacking. Pregnant mice were orally exposed to phenanthrene (0, 60 and 600 μg kg^-1 body weight) once every 3 days during gestation. In adult mouse offspring, in-utero phenanthrene exposure caused glucose intolerance and decreased insulin levels in females, while caused elevated fasting blood glucose and insulin levels in males. Serum resistin and interleukin-6 levels were elevated in offspring of both sexes. Serum adiponectin levels were decreased in females but increased in males. The insulin receptor signals were upregulated in the liver and downregulated in the skeletal muscle of F1 females, while they were inhibited in both tissues of F1 males. The visceral fat weight and body weight of the treated mice were not increased, suggesting that phenanthrene is not an obesogen, which is supported by the nonsignificant alteration in pparγ transcription in visceral adipose tissue. The transcription of retn in visceral adipose tissue was upregulated in both sexes, and that of adipoq was downregulated in females but upregulated in males, which were matched with the promoter methylation levels of these genes. The results indicated that phenanthrene exposure during gestation could disturb adipocytokine levels via epigenetic modification in adult offspring, and further influence glucose metabolism. These results might be helpful for understanding nonobesogenic pollutant-induced insulin resistance and preventing against diabetes without obesity.

Effects of benzo(a)pyrene at environmentally relevant doses on embryo-fetal development in rats

Studies have demonstrated that Benzo(a)Pyrene (BaP), a polycyclic aromatic hydrocarbon ubiquituous in the environment, can cause teratogenic effects. Since the majority of studies used in vitro models or high doses of BaP, this study evaluated the teratogenicity, reproductive and developmental performance of low doses of BaP through maternal and fetus examination after daily oral administration of BaP (0; 0.1; 1.0 or 10 μg/kg) to pregnant Wistar rats from Gestational day (GD) 6 to GD 15 (the organogenesis period). Pregnant rats did not exhibit clinical signs of toxicity during the exposure period. However, dams exposed to the lowest dose of BaP showed a reduction in the erythrocytes number and in the creatinine levels. The groups exposed to 0.1 and 1.0 μg/kg presented a decrease in placental efficiency, as well as an increase in placental weight. After fetal examination, the treated group with the lowest dose showed a reduced relative anogenital distance, while the curve of normal distribution of weight was changed in the highest dose group. In addition, anomalies evidenced by changes in the renal size and degree of fetal ossification were observed in treated-fetus. In conclusion, treatment with BaP during organogenesis at this dose level is detrimental to the normal development of fetuses.

Polycyclic aromatic hydrocarbons residues and the carcinogenic risk assessment to pregnant women in Nantong, China using QuEChERS method and HPLC-A pilot case study

A high-performance liquid chromatographic method with a modified QuEChERS extraction for the determination of polycyclic aromatic hydrocarbons (PAHs) in blood serum was developed to investigate the internal exposure level and the carcinogentic toxicity contribution rate of PAHs for pregnant women in Nantong, China. Venous blood (n = 48) was collected in the local hospital and the internal exposure level of 16 PAHs and the contribution rate of carcinogenicity to pregnant women were analyzed. Among all of the detected PAHs, the detection rate of pyrene (77.08%) was the highest, followed by naphthalene (64.58%) and benzo[a]anthracene (BaA, 45.83%). The carcinogenicity contribution rate of BaA (37.37%) was the highest, followed by fluorene (32.96%) and acenaphthylene (22.01%). The results showed that many kinds of carcinogenic PAHs can be detected in the serum of pregnant women in Nantong city, among which BaA should be paid most attention because of its high internal exposure level and carcinogenic risk. Meanwhile, the origins of general PAHs in serum samples were analyzed using the characteristic ratio analysis method. The PAH pollution level of air samples (n = 42) during the collection time of blood samples was also analyzed to compare the possible correlations between the two different results.

Biomarkers, matrices and analytical methods targeting human exposure to chemicals selected for a European human biomonitoring initiative

The major purpose of human biomonitoring is the mapping and assessment of human exposure to chemicals. The European initiative HBM4EU has prioritized seven substance groups and two metals relevant for human exposure: Phthalates and substitutes (1,2-cyclohexane dicarboxylic acid diisononyl ester, DINCH), bisphenols, per- and polyfluoroalkyl substances (PFASs), halogenated and organophosphorous flame retardants (HFRs and OPFRs), polycyclic aromatic hydrocarbons (PAHs), arylamines, cadmium and chromium. As a first step towards comparable European-wide data, the most suitable biomarkers, human matrices and analytical methods for each substance group or metal were selected from the scientific literature, based on a set of selection criteria. The biomarkers included parent compounds of PFASs and HFRs in serum, of bisphenols and arylamines in urine, metabolites of phthalates, DINCH, OPFRs and PAHs in urine as well as metals in blood and urine, with a preference to measure Cr in erythrocytes representing Cr (VI) exposure. High performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was the method of choice for bisphenols, PFASs, the HFR hexabromocyclododecane (HBCDD), phenolic HFRs as well as the metabolites of phthalates, DINCH, OPFRs and PAHs in urine. Gas chromatographic (GC) methods were selected for the remaining compounds, e.g. GC-low resolution MS with electron capture negative ionization (ECNI) for HFRs. Both GC-MS and LC-MS/MS were suitable for arylamines. New developments towards increased applications of GC-MS/MS may offer alternatives to GC-MS or LC-MS/MS approaches, e.g. for bisphenols. The metals were best determined by inductively coupled plasma (ICP)-MS, with the particular challenge of avoiding interferences in the Cd determination in urine. The evaluation process revealed research needs towards higher sensitivity and non-invasive sampling as well as a need for more stringent quality assurance/quality control applications and assessments.

Chronic Exposure to Environmental Level Phenanthrene Induces Non-Obesity-Dependent Insulin Resistance in Male Mice

Epidemiological evidence shows that the body burden of polycyclic aromatic hydrocarbons (PAHs) is related to the disruption of glucose homeostasis. However, the contribution of PAHs to the development of diabetes remains poorly documented. In the current work, male Kunming mice received phenanthrene (Phe) (5, 50, and 500 ng/kg) by gavage administration once every 2 days for 28 weeks. The significant elevation of homeostasis model assessment-insulin resistance (HOMA-IR) and HOMA-β cell, accompanied by hyperinsulinemia, indicated the occurrence of insulin resistance. The suppression of the insulin receptor signaling pathway in skeletal muscle might be responsible for glucose intolerance. Under the nonobese state, the serum levels of resistin, tumor necrosis factor-α, and interleukin-6 were elevated, whereas the levels of adiponectin were reduced. These changes in adipocytokine levels were consistent with their transcription in white adipose tissue. The promoter methylation levels of Retn (encoding resistin) and Adipoq (encoding adiponectin) were inversely correlated with their mRNA levels, indicating that Phe exposure could cause the disruption of adipocytokine secretion via epigenetic modification. The results would be helpful for understanding the pathogenesis in the development of T2DM caused by nonobesogenic pollutants.

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.

In utero exposure to phenanthrene induces hepatic steatosis in F1 adult female mice

Environmental pollutants are thought to be a risk factor for the prevalence of hepatic steatosis. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous, and human exposure is inevitable. In the present study, phenanthrene (Phe) was used as a representative PAH to investigate the effects of in utero exposure to PAH on hepatic lipid metabolism and the toxicological mechanism involved. Pregnant mice (C57BL/6J) were orally administered Phe (0, 60, 600 and 6000 μg kg-1 body weight) once every 3 days with 6 doses in total. F1 female mice aged 125 days showed significantly elevated hepatic lipid levels in the liver. The protein expression of hepatic peroxisome proliferator-activated receptors (PPARβ and PPARγ) and retinoid X receptors (RXRs) was upregulated; the transcription of genes related to lipogenesis, such as srebp1 (encoding sterol regulatory element binding proteins), acca (acetyl-CoA carboxylase), fasn (fatty acid synthase) and pcsk9 (proprotein convertase subtilisin/kexin type 9), showed an upregulation, while the mRNA levels of the lipolysis gene lcat (encoding lecithin cholesterol acyl transferase) were downregulated. These results could be responsible for lipid accumulation. The promoter methylation levels of pparγ were reduced and were the lowest in the 600 μg kg-1 group, and the promoter methylation levels of lcat were significantly increased in all the Phe treatments. These changes were matched with the alterations in their mRNA levels, suggesting that prenatal Phe exposure could induce abnormal lipid metabolism in later life via epigenetic modification.

Prenatal exposure to organic pollutants in northwestern Spain using non-invasive matrices (placenta and meconium)

Human exposure to environmental organic pollutants (OPs) begins in the uterine life period by trans-placental transfer. Epidemiological studies have consistently demonstrated the vulnerability of human fetuses and infants to the effects of OPs because of their rapid growth and organ development, cell differentiation, and immaturity of metabolism. The aim of the present study was to evaluate the prenatal exposure to OPs characterized by different physicochemical properties using non-invasive biological samples (meconium and placenta). A total of 88 placenta and 53 meconium samples were collected in Ourense, a city located in northwestern Spain, at the delivery and after birth from mothers and their infants from the University Hospital of Ourense, respectively. Selective pressurized liquid extraction (SPLE) methodologies were used to determine the targeted OPs in the selected biological samples. Cleanup of extracts was performed by solid-phase extraction (SPE) using EZ-POP cartridges and detection by gas chromatography (GC) coupled to tandem mass spectrometry (QqQ-MS/MS). The targeted OPs were detected with the following mean level total concentration order polycyclic aromatic hydrocarbons (PAHs) > organophosphorus pesticides (OPPs) > non-dioxin like polychlorinated biphenyls (NDLPCBs) > pyrethroids (PYRs) > polybrominated diphenyl ethers (PBDEs) > dioxin like polychlorinated biphenyls (DLPCBs) > organochlorine pesticides (OCPs) for placenta and ΣNDLPCBs > ΣPAHs > ΣOCPs > ΣPYRs > ΣOPPs > ΣDLPCBs > ΣPBDEs for meconium, respectively. Significant correlations (p < .050) between the socio-demographic characteristics of the selected population (mother's parity, age, weight increase during pregnancy, place of living and smoking habits) and log transformed concentration of some of the targeted OPs (OCPs, PBDEs, PYRs, OPPs and PAHs) were detected. The results obtained shown the complementary information given by both biological samples selected. Nevertheless, additional research will be needed to gain an understanding of the trans-placental transfer of OPs, to choose the best biological matrix to evaluate the prenatal exposure to OPs in a correct way and to know their health implications.

Placental levels of polycyclic aromatic hydrocarbons (PAHs) and their association with birth weight of infants

As an alarming group of pollutants, polycyclic aromatic hydrocarbons (PAHs) gather much public health concern not only because of their carcinogenic or co-carcinogenic risk but also by interfering with hormone systems or by causing oxidative damage, henceforth liable to toxic actions on reproduction. Accordingly, the present study was aimed to explore the association between in-utero exposure to PAHs by evaluating their placental levels and infant birth weight among 110 healthy and nonsmoking pregnant women. Placental tissue samples were collected instantly after delivery and were analyzed for the presence of sixteen Environmental Protection Agency (EPA) listed PAHs with the help of Gas chromatography equipped with flame ionization detector (GC-FID). Chrysene and benzo(k)fluoranthene were the predominant PAHs detected in tissue samples. To assess the source of origin of PAHs in placenta tissue samples, the ratio of low molecular weight PAHs to high molecular weight (∑LMW/∑HMW PAHs) was calculated, showing the predominance of pyrogenic sources of PAHs possibly responsible for the exposure of the studied population. Results of regression analysis demonstrated the inverse although not significant association of naphthalene (Nap), acenaphthylene (Acy), anthracene (Anth), pyrene (Pyr), benzo(b)fluoranthene (BbF), benzo(k)Fluoranthene (BkF), benzo(a)pyrene (BaP), indeno (123 cd pyrene (IcdP), dibenzo(ah)anthracene (DahA) and benzo(ghi)Perylene (BghiP) with birth weight of neonates. Additionally, the regression model lay light upon the significant association of fluoranthene (Fla) (coefficient= -1.41 gram, p < 0.05) to the depletion trend of birth weight after adjusting for potential covariates. These findings suggest the possible role of an environmental contaminants like PAHs on impairment of fetal growth.