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The emerging environmental pollutant hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been of particular concern in recent years due to their ubiquitous distribution in environmental matrices and adverse health effects. Since there is no industrial-scale manufacturing of OH-PBDEs, their origins are inconclusive and not fully understood, thus triggering extensive discussions among the academic community. Recently, the polymerization of simple bromophenols (BrPs) has been identified as an important origin of OH-PBDEs, which are widely reported in various oxidation processes. This review comprehensively surveyed previous studies about OH-PBDEs formation from BrPs precursors in both natural (e.g., photochemical processes, naturally occurring manganese oxides, enzymes-mediated oxidation) and engineered processes (e.g., ozonation, chlorination, permanganate/ferrate associated oxidation, radicals based oxidation, nonradically activated persulfates). Generally, oxidative coupling reactions of bromophenoxyl radicals resulting from BrPs were recognized as the main mechanism for OH-PBDEs formation, which were discussed emphatically by combining theoretical calculations with the experimental evidence. Some discrepancies were found in interpreting the preferential coupling pathway of bromophenoxyl radicals according to different calculation methods. So, further efforts are needed to use advanced analytical methods for sensitive identification of OH-PBDEs to better evaluate the formation potentials of diverse OH-PBDEs from BrPs. Carbon materials associated oxidation technologies (e.g., carbon nanotube activated ferrate or persulfates) may be applied as a promising method for controlling OH-PBDEs during treatment of BrPs-containing waters. Overall, this review reveals a prevalent phenomenon of BrPs transformation to OH-PBDEs and meanwhile advances the mechanistic understanding. Moreover, the knowledge gaps are identified and some recommendations are proposed for future studies. [ABSTRACT FROM AUTHOR]

Quantifying the root uptake of hydrophobic organic contaminants (HOCs) by plants remains challenging due to the lack of data on the freely available fractions of HOCs in soil porewater. We therefore hypothesized that a passive sampler could act as a useful tool to evaluate the root uptake potential and pathways of HOCs by plants in soil. We tested this hypothesis by exploring the uptake of polybrominated diphenyl ethers (PBDEs) and organophosphate esters (OPEs) by carrot and lettuce with the codeployment of passive samplers in a contaminated soil system. The results showed that the amounts of PBDEs enriched in carrot and lettuce were positively correlated with those in a passive sampler (r2 = 0.46–0.88). No concentration correlation was observed for OPEs between lettuce and passive samplers, due to possible degradation of OPEs in lettuce. The root‐to‐porewater ratios of PBDEs and OPEs, respectively, were 6.2 to 11 and 0.05 to 0.88 L g−1 for carrot, and 8.8 to 130 and less than reporting limits to 1.2 L g−1 for lettuce. The ratios were negatively correlated with log KOW values for carrot, but increased with increasing log KOW values over a range of 1.97 to 6.80, and then decreased with log KOW values greater than 6.80 for lettuce. This finding indicated that passive transport and partition were the accumulation pathways of PBDEs and OPEs in carrot and lettuce, respectively. Overall, passive samplers performed adequately in assessing the available fractions of persistent HOCs in plants, and can serve as a viable tool for exploring the pathways for plant root uptake of HOCs. Environ Toxicol Chem 2024;43:2338–2349. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Background: With the high influx of low-cost plastic toys on the market, there is growing concern about the safety of such toys. Some of these plastic toys contains hazardous chemicals like polybrominated diphenyl ethers (PBDEs) due to the use of recycled plastics in new toy manufacturing. Here, we investigated if toys marketed in Europe are compliant with EU directives to assess the safety of currently used children's toys and identify implications of PBDE content in toys. Results: Eighty-four toys purchased from international toy retailers were screened for bromine using X-ray fluorescence (XRF), and 11 of those with bromine content higher than 500 µg/g were analyzed for ten PBDEs using GC–HRMS. PBDEs were detected in all 11 toys. Ʃ10PBDE concentrations ranged up to 23.5 mg/g (with a median concentration of 8.61 mg/g), with BDE-209 being the most abundant compound (4.40 mg/g). Eight samples exceeded the EU's Low POP Content Limit (LPCL) of 500 µg/g for the Ʃ10PBDEs by 6–47 times and the Unintentional Trace Contaminant (UTC) limits of 10 µg/g for Deca-BDE by 12–800 times. Conclusions: PBDEs were up to percent levels, suggesting direct recycling of flame retarded plastic, e.g., e-waste plastics, into toy components. This is a call for concern and requires intervention from all stakeholders involved in the toy market. Overall, the occurrence of non-compliant toys in the EU market, as indicated in this study is primarily attributed to gaps in regulations, inadequate legislation for recycled plastics, the rise of online sales, complexities in global and national supply chains, and economic challenges. Failure to address these issues will hinder the efforts of the plastics industry to transition into a circular economy. This suggests that more actions are needed to address gaps in cross-border enforcement, and stricter sanctions are required for toy manufacturers who fail to adhere to regulations and safety standards. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the associations of plasma polybrominated diphenyl ether (PBDE) concentrations in early pregnancy with gestational weight gain (GWG). Design: Prospective cohort study. Setting: US‐based, multicentre cohort of pregnant women. Population: We used data from 2052 women without obesity and 397 women with obesity participating in the NICHD Fetal Growth Studies – Singleton Cohort, with first‐trimester plasma PBDE concentrations and weight measurements throughout pregnancy. Methods: We applied generalised linear models and Bayesian kernel machine regression (BKMR) to evaluate both the individual and joint associations of PBDEs with measures of GWG, adjusting for potential confounders. Main outcome measures: Total GWG (kg), total and trimester‐specific GWG velocities (kg/week), and GWG categories and trajectory groups. Results: Mean pre‐pregnancy BMIs were 23.6 and 34.5 kg/m2 for women without and with obesity, respectively. Among women without obesity, there were no associations of PBDEs with any GWG measure. Among women with obesity, one standard deviation increase in log‐transformed PBDE 47 was associated with a 1.87 kg higher total GWG (95% CI 0.39–3.35) and a 0.05 kg/week higher total GWG velocity (95% CI 0.01–0.09). Similar associations were found for PBDE 47 in BKMR among women with obesity, and PBDE 47, 99 and 100 were associated with lower odds of being in the low GWG trajectory group. Conclusions: PBDEs were not associated with GWG among individuals without obesity. Among those with obesity, only PBDE 47 showed consistent positive associations with GWG measures across multiple statistical methods. Further research is needed to validate this association and explore potential mechanisms. [ABSTRACT FROM AUTHOR]

Legacy brominated flame retardants, including polybrominated diphenyl ethers (PBDEs), have been classified as persistent organic pollutants and replaced with novel brominated flame retardants (NBFRs). The octanol–water partition coefficients (log KOW) of NBFRs have been computationally estimated, but the log KOW values provided by these methods can differ by 1 to 3 orders of magnitude. Given the importance of this parameter in fate and toxicity models, we indirectly measured the log KOW values of eight NBFRs by their capacity factor (k′) on a reversed‐phase high‐performance liquid chromatography (HPLC) C18 column by isocratic elution and compared these measured values with those estimated by nine computational models. Log KOW values were obtained for the NBFRs 1,2‐bis(2,4,6‐tribromophenoxy) ethane, pentabromobenzene, pentabromoethylbenzene, pentabromotoluene, 2‐ethylhexyl 2,3,4,5‐tetrabromobenzoate, allyl 2,4,6‐tribromophenylether, 2,3‐dibromopropyl‐2,4,6‐tribromophenyl ether, and bis(2‐ethylhexyl) tetrabromophthalate. A training set of phthalates, polychlorinated biphenyls, PBDEs, and halogenated benzenes were chosen to obtain the log k′–log KOW calibration for the NBFRs. The computational models KowWIN, XLogP3, EAS‐E Suite, COSMOtherm, DirectML, and Abraham polyparameter linear free energy relationships all predicted the log KOW values of the calibration compounds to within 1 order of magnitude without significant bias. The median of these models predicted log KOW values for the calibration compounds that were close to those known in the literature with root mean square error (RMSE) = 0.224 and for the NBFRs that were close to those measured by HPLC (RMSE = 0.334). Environ Toxicol Chem 2024;43:2105–2114. © 2024 SETAC [ABSTRACT FROM AUTHOR]

As the most common endocrine cancer, thyroid cancer (TC) has sharply increased globally over the past three decades. The growing incidence of TC might be counted by genetics, radiation, iodine, autoimmune disease, and exposure to environmental endocrine–disrupting chemicals (EDCs). Polybrominated diphenyl ethers (PBDEs), being typical EDCs, have been widely utilized in plastics, electronics, furniture, and textiles as flame retardants since the 1980s, and research has indicated a significant correlation between their exposure and the risk of TC. Even so, PBDEs exposure impact on the metabolic signature for TC remains unexplored. In this study, eight congeners of PBDEs were determined in serum from 111 patents with papillary thyroid cancer (PTC) and 111 healthy participants based on case–control epidemiology using gas chromatography–atmospheric pressure chemical ionization–tandem mass spectrometry (GC-APCI–MS/MS). Based on the tertile distribution of total PBDEs concentrations in 59 participants, metabolomics analysis was further performed by ultra-high performance liquid chromatography coupled to hybrid quadrupole–Orbitrap MS. In the partial correlation analysis, the 29 identified metabolites were correlated with PBDEs exposure (P < 0.05). In addition, PBDEs disrupted the metabolism of glycerophospholipids, sphingolipids, taurine, and hypotaurine, indicating that neurotransmitters, oxidative stress, and inflammation are the vulnerable pathways affected in PTC. Furthermore, (±)-octopamine and 5-hydroxyindole, both of which modulate the actions of neurotransmitters, emerged as potential disturbed metabolite markers for TC following exposure to PBDEs. This study analyzed the impact of PBDEs on PTC in terms of the metabolic changes and further explored possible biomarkers, which helped us have a deep understanding of the possible mechanism of the effects of PBDEs on TC. [ABSTRACT FROM AUTHOR]

CDK7 and FynB protein kinases have been recognized as relevant targets for cancer and brain diseases treatment due to their pivotal regulatory roles in cellular functions such as cell cycle and neural signal transduction. Several studies demonstrated that the inhibition of these proteins could be useful in altering the onset or progression of these diseases. Based on bioassay-guided approach, the extract of the marine sponge Lendenfeldia chondrodes (Thorectidae), which exhibited interesting kinase inhibitory activities, was fractionated. The investigation led to the isolation of five known 1–5 and one new 6 polybrominated diphenyl ethers (PBDEs). Their structure elucidation was established based on spectroscopic data (NMR and HRMS) and comparison with literature data. [ABSTRACT FROM AUTHOR]

Children on the autism spectrum have been shown to have immune dysregulation that often correlates with behavioral deficits. The role of the post-natal environment in this dysregulation is an area of active investigation. We examined the association between plasma levels of polybrominated diphenyl ether (PBDE) and immune cell function in age-matched autistic children and non-autistic controls. Plasma from children on the autism spectrum (n = 38) and typically developing controls (TD; n = 60) were analyzed for 14 major PBDE congeners. Cytokine/chemokine production was measured in peripheral blood mononuclear cell (PBMC) supernatants with and without ex vivo BDE-49 exposure. Total plasma concentration (∑PBDE14) and individual congener levels were also correlated with T cell function. ∑PBDE14 did not differ between diagnostic groups but correlated with reduced immune function in children on the autism spectrum. In autistic children, IL-2 and IFN-γ production was reduced in association with several individual BDE congeners, especially BDE-49 (p = 0.001). Furthermore, when PBMCs were exposed ex vivo to BDE-49, cells from autistic children produced elevated levels of IL-6, TNF-α, IL-1β, MIP-1α and MCP-1 (p

Polybrominated diphenyl ethers (PBDEs) are synthetic organic compounds that have been used as brominated flame retardants. They are persistent in the environment, can bioaccumulate in fatty tissues, biomagnify through the food chain, and have adverse health effects on humans and wildlife. The main source of human exposure to PBDEs is the ingestion of contaminated food. Therefore, in this study the concentration of BDE-28, BDE-47, BDE-77, BDE-99, BDE-100, BDE-126, BDE-139, BDE-153, BDE-154, and BDE-183 was determined by gas chromatography coupled to mass spectrometry in shrimps and animal origin oils commercialised and consumed in Medellín, Colombia. All samples of shrimps and animal origin oils analysed had values below 0.0050 ng·g−1 for all the PBDEs studied, with the exception of one shrimp sample in which a concentration of 0.012 ± 0.0056 ng·g−1 of BDE-100 was quantified. The results suggest that shrimps and animal origin oils are not a significant source of exposure to PBDEs of the population of the city. However, it is important to continue analysing PBDEs in foods, including foods other than those evaluated in this investigation, in order to guarantee the innocuity and safety of the food consumed by the population. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs), commonly used as synthetic flame retardants, are present in a variety of consumer products, including electronics, polyurethane foams, textiles, and building materials. Initial evidence from epidemiological and experimental studies suggests that maternal PBDE exposure may be associated with a higher BMI in children, with disturbance of energy metabolism and an increased risk of Type 2 diabetes. However, the causality between early exposure to real-life PBDE concentrations and increased weight as well as mechanisms underlying impaired metabolic pathways in the offspring remain elusive. Here, using a mouse model we examined the effect of maternal exposure to 2,2′,4,4′-tetrabrominated diphenyl ether (BDE-47), the most abundant congener in human samples, on offspring weight gain and energy homeostasis using a mouse model. Maternal exposure to BDE-47 at low dose resulted in weight gain in female offspring together with an impaired glucose and insulin tolerance in both female and male mice. In vitro and in vivo data suggest increased adipogenesis induced by BDE-47, possibly mediated by DNA hypermethylation. Furthermore, mRNA data suggest that neuronal dysregulation of energy homeostasis, driven via a disturbed leptin signaling may contribute to the observed weight gain as well as impaired insulin and glucose tolerance. [ABSTRACT FROM AUTHOR]

Many persistent organic pollutants (POPs) are suspected endocrine disruptors and it is important to investigate their effects at low concentrations relevant to human exposure. Here, the OECD test guideline #456 steroidogenesis assay was downscaled to a 96-well microplate format to screen 24 POPs for their effects on viability, and testosterone and estradiol synthesis using the human adrenocortical cell line H295R. The compounds (six polyfluoroalkyl substances, five organochlorine pesticides, ten polychlorinated biphenyls and three polybrominated diphenyl ethers) were tested at human-relevant levels (1 nM to 10 µM). Increased estradiol synthesis, above the OECD guideline threshold of 1.5-fold solvent control, was shown after exposure to 10 µM PCB-156 (153%) and PCB-180 (196%). Interestingly, the base hormone synthesis varied depending on the cell batch. An alternative data analysis using a linear mixed-effects model that include multiple independent experiments and considers batch-dependent variation was therefore applied. This approach revealed small but statistically significant effects on estradiol or testosterone synthesis for 17 compounds. Increased testosterone levels were demonstrated even at 1 nM for PCB-74 (18%), PCB-99 (29%), PCB-118 (16%), PCB-138 (19%), PCB-180 (22%), and PBDE-153 (21%). The MTT assay revealed significant effects on cell viability after exposure to 1 nM of perfluoroundecanoic acid (12%), 3 nM PBDE-153 (9%), and 10 µM of PCB-156 (6%). This shows that some POPs can interfere with endocrine signaling at concentrations found in human blood, highlighting the need for further investigation into the toxicological mechanisms of POPs and their mixtures at low concentrations relevant to human exposure. [ABSTRACT FROM AUTHOR]

Human influence on Antarctic marine ecosystems is a growing concern, despite limited information being available. This study investigated the coastal meiofauna and environmental parameters of 10 locations, 4 of which served as reference points (OB1, OB2, OB3, and McGrady) and 6 which were impacted by different levels of human activity in the past and present (Wharf, Wilkes, BBIN, BBMID, BBOUT, and Shannon) in East Antarctica. Environmental variables such as metals, total petroleum hydrocarbons (TPHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), grain size, organic matter content, and nutrients were measured for analysis. Locations close to human activities showed higher concentrations of pollutants (metals, TPHs, PBDEs, PCBs) and greater variations in meiofauna diversity compared to the reference sites (OB1, OB2, OB3, and McGrady). In the area impacted by the Casey Station waste dump (Brown Bay), the meiofauna community at the location furthest from the pollution (BBOUT) source exhibited greater diversity compared to the closest location (BBIN). In addition to metals and TPHs, particle size was also correlated with community patterns, with finer sediments associated with more impacted sites, facilitating the accumulation of toxic compounds. These results contribute to the understanding of the role and impact of pollutants on meiofauna biodiversity in Antarctic coastal ecosystems. [ABSTRACT FROM AUTHOR]

AbstractFrom the past to the present, many chemicals have been used for the purpose of flame retardant. Due to PBDEs’ (Polybrominated diphenyl ether) lipophilic and accumulative properties, some of them are banned from the market. As an alternative to these chemicals, OPFRs (organophosphorus flame retardants) have started to be used as flame retardants. In this article, acute toxicity profiles, mutagenicity, carcinogenicity, blood-brain barrier permeability, ecotoxicity and nutritional toxicity as also AHR, ER affinity and MMP, aromatase affinity, CYP2C9, CYP3A4 interaction of the of 16 different compounds of the OPFRs were investigated using a computational toxicology method; ProTox- 3.0. According to our results, eight compounds were found to be active in terms of carcinogenic effect, whereas two compounds were found to be active for mutagenicity. On the other hand, all compounds were found to be active in terms of blood-barrier permeability. Fourteen compounds and four compounds are found to have ecotoxic and nutritional toxic potency, respectively. Eight compounds were determined as active to AhR, and four chemicals were found to be active in Estrogen Receptor alpha. Eight chemicals were found to be active in terms of mitochondrial membrane potency. Lastly, three chemicals were found to be active in aromatase enzymes. In terms of CYP interaction potencies, eight compounds were found to be active in both CYP2C9 and CYP3A4. This research provided novel insights into the potential toxic effects of OPFRs. However, further studies are needed to evaluate their toxicity. Moreover, these findings lay the groundwork for in vitro and in vivo toxicity research. [ABSTRACT FROM AUTHOR]

Indoor house dust is considered an important human exposure route to polybrominated diphenyl ethers (PBDEs), which has raised concern about their environmental persistence and toxicity properties. In this study, eight PBDEs (BDE-28, -47, -99, -100, -153, -154, -183, and -209) were determined in house dust from two cities with different socio-demographic characteristics from Brazil, examining possible relationships with factors that potentially influence contamination (population density, economic activities, presence of electronic equipment, and so on) and also estimating the risk of human exposure through oral ingestion and dermal contact. The Σ8PBDE concentration in Sorocaba city ranged between 380 and 4269 ng/g dw, while in Itapetininga city ranged from 106 to 1000 ng/g dw. In both regions, BDE-209 was the most abundantly found congener, followed by BDE-99. House dust from Sorocaba presented significantly greater concentrations of BDE-183 and BDE-209 than Itapetininga. Regarding risk exposure assessment, the estimated daily intake (EDI) of PBDEs was much lower than their respective reference doses (RfDs) in all pathways estimated (non-dietary ingestion and dermal contact). This study provided valuable data to improve the knowledge about the presence and exposure to PBDEs in Brazilian house dust in comparison to other developing countries and the need to control environmental pollution and protect human health. [ABSTRACT FROM AUTHOR]

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Milk can be contaminated with organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs), which are known as endocrine disruptors (EDCs). However, the relationship between the lactation period of cows and the residues of EDCs is unknown. The aim of this study was to determine the relationship between the lactation period in cows and EDCs residues such as OCPs, PCBs, PBDEs, and PAHs. Milk collected from cows during each lactation period was analyzed in terms of fat content and EDC residues. One or more contaminants were detected in almost all (98%) of the milk taken in three lactation periods. Three PCBs and 11 PAHs were found together in 1st lactation period, and one more PAH was added to them in other periods. However, the sample rate exceeded the maximum residue limit of 48%, 10%, and 16% in the first, second and third lactation periods, respectively. Also, it was seen that the riskiest period was the first lactation period, followed by the third and second periods. The same ranking is valid for the fat content in milk. Thus, it was concluded that the excretion of lipophilic EDCs in milk is related to the fat content in milk, and the higher the fat content in milk, the more lipophilic EDCs are excreted in milk. [ABSTRACT FROM AUTHOR]

Persistent organic pollutants pose a great threat to amphibian populations, but information on the bioaccumulation of contaminants in amphibians remains scarce. To examine the tissue distribution and maternal transfer of organic halogenated pollutants (OHPs) in frogs, seven types of tissues from black‐spotted frog (muscle, liver, kidney, stomach, intestine, heart, and egg) were collected from an e‐waste–polluted area in South China. Among the seven frog tissues, median total OHP concentrations of 2.3 to 9.7 μg/g lipid weight were found (in 31 polychlorinated biphenyl [PCB] individuals and 15 polybrominated diphenyl ether [PBDE], dechlorane plus [syn‐DP and anti‐DP], bexabromobenzene [HBB], polybrominated biphenyl] PBB153 and ‐209], and decabromodiphenyl ethane [DBDPE] individuals). Sex‐specific differences in contaminant concentration and compound compositions were observed among the frog tissues, and eggs had a significantly higher contaminant burden on the whole body of female frogs. In addition, a significant sex difference in the concentration ratios of other tissues to the liver was observed in most tissues except for muscle. These results suggest that egg production may involve the mobilization of other maternal tissues besides muscle, which resulted in the sex‐specific distribution. Different parental tissues had similar maternal transfer mechanisms; factors other than lipophilicity (e.g., molecular size and proteinophilic characteristics) could influence the maternal transfer of OHPs in frogs. Environ Toxicol Chem 2024;43:1557–1568. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Flame retardants, widely used in industry as chemicals in additives for consumer products such as electronics, automobiles, polyurethane foams, and textiles, are used to reduce the likelihood of fire in flammable materials. Traditional flame retardants such as polybrominated diphenyl ethers have been proved to have environmental pollution and toxicity problems in several studies, and in order to solve these problems, a series of new flame retardants (NBFRs), represented by decabromodiphenyl ethane (DBDPE), have emerged. As a kind of new pollutant, NBFRs have been reported in industrially developed regions such as the Bohai Rim and Beijing-Tianjin-Hebei regions, as well as in remote regions such as the bipolar regions. As the third pole of the world, the Tibetan Plateau, with low industrialization and sparsely populated, is an important region to study the atmospheric long-range transport and environmental impacts of NBFRs, as is the case for the bipolar regions. In this paper, we summarize the NBFRs studies conducted in the Tibetan Plateau region in recent years, including soil, moss, atmosphere, and water media, and the study area covers a number of typical regions in the Tibetan Plateau. The concentration and detection rate of DBDPE have been reported to be the highest in all matrices on the Tibetan Plateau. However, few studies have been conducted on the Tibetan Plateau and further research is needed to fill the gap of new contaminants in the region. [ABSTRACT FROM AUTHOR]

Objective To analyse the relationship between the occurrence of type 2 diabetes mellitus (T2DM) and exposure to polybrominated diphenyl ethers (PBDEs), and to construct and evaluate the predictive model for the occurrence of T2DM by machine learning methods. Methods Totally 1 425 study subjects were screened in the NHANES database, including 1132 non-T2DM patients and 293 T2DM patients. The clinical data of non-T2DM patients and T2DM patients were compared, and those with statistically significant differences were taken for further screening of boruta features to clarify the relationship between T2DM occurrence and PBDEs and their influencing factors. The screened influencing factors for the occurrence of T2DM were input into R software, and the data were randomly partitioned according to 80% training set and 20% validation set using the R software create Data Partition function. Seven algorithms, including logistic regression (Logistcs), extreme gradient boosting (XGBoost), light gradient boosting (LightGBM), adaptive boosting (Ad aBoost), K-nearest neighbours (KNN), plain Bayesian (CNB), and support vector machine (SVM) were used to con⁃ struct the machine learning model, and the training set was input into the model for training, and the validation set was in⁃ put into the model. The model was internally validated using ten-fold cross-validation pairs. The models were evaluated by combining the ROC curve and AUC, and the model with the best prediction performance was selected for external validation. The best predictive model was externally validated by selecting 71 cases of adult T2DM patients and 100 cases of health check-ups from the Department of Endocrinology of the First Affiliated Hospital of Xinjiang Medical University. The SHAP tool was used to analyse the interpretability of the high-performance prediction models and to judge the importance of each feature of the models in the decision-making process. Results BMI, waist circumference, education level, the proportion with family history of diabetes, serum HDL and serum BDE-28, BDE-47, BDE-99, BDE-183, BDE-209 concentrations were higher in T2DM patients than in non-T2DM patients (all P<0. 05). Boruta characteristics screening determined waist circumference, BMI, family history of diabetes and serum BDE- 47, BDE-99, BDE-28, BDE-209, and BDE183 as influencing factors for the occurrence of T2DM, which were incorporated into the machine learning algorithm to construct the predictive model of T2DM occurrence. The XGBoost model had the highest AUC value in both the training set and the internal validation of the validation set, and was in the top rank in terms of accuracy, Kappa value, sensitivity, and specificity, so it was chosen as a high-efficiency prediction model. The results of external validation showed that the XGBoost model had an accuracy of 0. 702, a sensitivity of 0. 549, a specificity of 0. 787, and an AUC (95% CI) of 0. 674 (0. 575-0. 773). Interpretive analyses of the predictions of the XGBoost model by the SHAP tool showed that waist circum⁃ ference and serum BDE-47 were the most important predictive features, while serum BDE-99, BDE-209 and BMI, family history of diabetes had high importance in the model, while serum BDE-28, BDE-183 had relatively low importance in the model. Conclusions Serum BDE-47, BDE-99, BDE-28, BDE-209, and BDE-183 are influential factors for the occurrence of T2DM, and the XGBoost model based on serum PBDEs, waist circumference, BMI, family history of diabetes mellitus has a high predictive efficacy for the occurrence of T2DM, which is of value in the prediction of the occurrence of T2DM. [ABSTRACT FROM AUTHOR]

Flame retardants have been shown to cause widespread physiological effects, in particular on endocrine organs such as the thyroid. This review aims to provide an overview of the literature on the association between flame retardants and thyroid function within humans. A search in the National Library of Medicine and National Institutes of Health PubMed database through January 2024 yielded 61 studies that met the inclusion criteria. The most frequently analyzed flame retardants across all thyroid hormones were polybrominated diphenyl ethers (PBDEs), in particular BDE-47 and BDE-99. Ten studies demonstrated exclusively positive associations between flame retardants and thyroid stimulating hormone (TSH). Six studies demonstrated exclusively negative associations between flame retardants and TSH. Twelve studies demonstrated exclusively positive associations for total triiodothyronine (tT3) and total thyroxine (tT4). Five and eight studies demonstrated exclusively negative associations between flame retardants and these same thyroid hormones, respectively. The effect of flame retardants on thyroid hormones is heterogeneous; however, the long-term impact warrants further investigation. Vulnerable populations, including indigenous people, individuals working at e-waste sites, firefighters, and individuals within certain age groups, such as children and elderly, are especially critical to be informed of risk of exposure. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) have been used for many years as flame retardants. Due to their physicochemical and toxicological properties, they are considered to be persistent organic pollutants (POPs). BDE-209 is the main component of deca-BDE, the one PBDE commercial mixture currently approved for use in the European Union. The aim of this study was to analyse BDE-209 in surface soil samples from Warsaw and surrounding areas (Poland) as an indicator of environmental pollution with PBDEs, and to characterise the associated health risk. A total of 40 samples were analysed using gas chromatography with electron capture detection (GC-µECD). Concentrations of BDE-209 in soil ranged from 0.4 ng g−1 d.w. (limit of quantification) to 158 ng g−1 d.w. Overall, 52.5% of results were above the method's limit of quantification. The highest levels were found at several locations with heavy traffic and in the vicinity of a CHP plant in the city. The lowest concentrations were observed in most of the samples collected from low industrialized or green areas (<0.4 to 1.68 ng g−1 d.w.). Exposure to BDE-209 was estimated for one of the most sensitive populations, i.e., young children. The following exposure routes were selected: oral and dermal. No risk was found to young children's health. [ABSTRACT FROM AUTHOR]

This study systematically investigated the pollution levels and migration trends of PBDEs in soils and plants around engineering plastics factory, and identified the ecological risks of PBDEs in the environment around typical pollution sources.The results showed that 13 kinds of PBDEs were widely detected in the surrounding areas, and the concentration level was higher than the general environmental pollution level. The total PBDE concentrations (∑13PBDEs) in soils ranged from 14.6 to 278.4 ng/g dry weight (dw), and in plants ranged from 11.5 to 176 ng/g dw. Both soil and plant samples showed that BDE-209 was the most important congener, the pollution level in soil and plant was similar, and the composition of PBDEs congener was similar. In the soil column (50 cm), the radial migration of PBDEs was mainly concentrated in the 0–30 cm section. Except for BDE-66, which was mainly located in the 20–30 cm soil layer, the concentration of PBDEs was the highest in the 0–10 cm region. Furthermore, the environmental risks of PBDEs in soil and plants were evaluated by hazard quotient method, and the HQ values were all < 1, which did not exhibit any ecological risk. The evaluation results also showed that the ecological risk of PBDEs in soil was higher than that of plants, especially penta-BDE, which should be paid more attention. [ABSTRACT FROM AUTHOR]

[Display omitted] • Electronic products sorted by black, white or other color are called chromoproducts. • Chromoproducts were categorized according to their likelihood of POP-BFRs content. • Chromoproduct approach used to sort polluted/clean plastic at e-waste facilities. • Bromine and antimony contents by weight might be indicators of POP-BFRs pollution. • Chromoproducts composition and plastics separated by polymer type allowed upcycling. Research to prevent releases of brominated flame retardants listed as persistent organic pollutants by the Stockholm Convention (POP-BFRs) was conducted through an international cooperation project in Colombia. Six waste electrical and electronic equipment (WEEE) management facilities implemented: 1) sorting e-waste by product type and color (black, white, and other; henceforth called chromoproducts), 2) sampling test products and their plastic fraction (called sets, separated by polymer type), 3) monitoring mass, bromine and antimony contents by hand-held X-ray fluorescence (XRF) and POP-BFRs such as polybrominated diphenyl ethers (PBDEs) by gas chromatography and mass spectrometry (GC–MS), and 4) differentiated treatment according to categories that used the Restriction of Hazardous Substances in Electrical and Electronic Equipment Directive (RoHS) hazardousness threshold of 1000 mg ∑PBDEs/kg. This scheme led to the proposal of a methodology for WEEE management called the "chromoproduct approach". 994,230 products were managed and grouped into 222 chromoproducts, from which 77 were analyzed: 50 below RoHS hazardousness (BRH), 16 above RoHS hazardousness (ARH), and 11 unknown RoHS hazardousness (URH). XRF indicators using bromine and antimony contents could rule out pollution in BRH chromoproducts; however, categorization still required GC–MS. One ARH plastics sample had 3620 mg ∑PBDEs/kg, while no POP-BFRs were found in the BRH plastics sample. The implementation of the chromoproduct approach traced 153.6 tonnes of ARH plastics. BRH plastics composition was estimated and used in a pilot-scale closed-loop economic activity. The chromoproduct approach seems promising for avoiding POP-BFR releases and promoting the upcycling of recyclable e-waste plastics. [ABSTRACT FROM AUTHOR]

Legacy contaminants and contaminants of emerging concern (CECs) were assessed in tree swallow (Tachycineta bicolor) tissue and diet samples from three drainages in the Milwaukee estuary, Wisconsin, USA, to understand exposures and possible biomarker responses. Two remote Wisconsin lakes were assessed for comparative purposes. Bioaccumulative classes of contaminants, such as polybrominated diphenyl ethers and per‐ and polyfluoroalkyl substances, while at higher concentrations than the reference lakes, did not vary significantly among sites or among the three drainages. Polycyclic aromatic hydrocarbons were assessed in diet and sediment and were from primarily pyrogenic sources. Ten biomarkers were assessed relative to contaminant exposure. Polychlorinated biphenyls (PCBs) were elevated above reference conditions at all Milwaukee sites but did not correlate with any measured biomarker responses. Only one site, Cedarburg, just downstream from a Superfund site, had elevated PCBs compared to other sites in the Milwaukee estuary. Few non‐organochlorine insecticides or herbicides were detected in tree swallow liver tissue, except for the atrazine metabolite desethylatrazine. Few pharmaceuticals and personal care products were detected in liver tissue except for N,N‐diethyl‐meta‐toluamide, iopamidol, and two antibiotics. The present study is one of the most comprehensive assessments to date, along with the previously published Maumee River data, on the exposure and effects of a wide variety of CECs in birds. Environ Toxicol Chem 2024;43:856–877. © 2024 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA. [ABSTRACT FROM AUTHOR]

The incidence of endocrine-related cancer, which includes tumors in major endocrine glands such as the breast, thyroid, pituitary, and prostate, has been increasing year by year. Various studies have indicated that brominated flame retardants (BFRs) are neurotoxic, endocrine-toxic, reproductive-toxic, and even carcinogenic. However, the epidemiological relationship between BFR exposure and endocrine-related cancer risk remains unclear. We searched the PubMed, Google Scholar, and Web of Science databases for articles evaluating the association between BFR exposure and endocrine-related cancer risk. The odds ratio (OR) and its corresponding 95% confidence interval (95% CI) were used to assess the association. Statistical heterogeneity among studies was assessed with the Q-test and I 2 statistics. Begg's test was performed to evaluate the publication bias. We collected 15 studies, including 6 nested case-control and 9 case-control studies, with 3468 cases and 4187 controls. These studies assessed the risk of breast cancer, thyroid cancer, and endocrine-related cancers in relation to BFR levels. Our findings indicate a significant association between BFR exposure in adipose tissue and an increased risk of breast cancer. However, this association was not observed for thyroid cancer. Generally, BFR exposure appears to elevate the risk of endocrine-related cancers, with a notable increase in risk linked to higher levels of BDE-28, a specific polybrominated diphenyl ether congener. In conclusion, although this meta-analysis has several limitations, our results suggest that BFR exposure is a significant risk factor for breast cancer, and low-brominated BDE-28 exposure could significantly increase the risk of endocrine-related cancers. Further research is essential to clarify the potential causal relationships between BFRs and endocrine-related cancers, and their carcinogenic mechanisms. • This is the first meta-analysis on BFR exposure and endocrine-related cancer. • BFR exposure appears to elevate the risk of endocrine-related cancers. • BFR exposure in adipose tissue is associated with an increased risk of breast cancer. • BDE-28 increased the risk of endocrine-related cancer. [ABSTRACT FROM AUTHOR]

Context: Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are two families of persistent organic pollutants that are dangerous as they remain in the atmosphere for long periods and are toxic for humans and animals. They are found all over the world, including the penguins of Antarctica. One of the mechanisms that explains the toxicity of these compounds is related to oxidative stress. The main idea of this theoretical research is to use conceptual density functional theory as a theory of chemical reactivity to analyze the oxidative stress that PCBs and PBDEs can produce. The electron transfer properties as well as the interaction with DNA nitrogenous bases of nine PCBs and ten PBDEs found in Antarctic penguins are investigated. From this study, it can be concluded that compounds with more chlorine or bromine atoms are more oxidizing and produce more oxidative stress. These molecules also interact directly with the nitrogenous bases of DNA, forming hydrogen bonds, and this may be an explanation for the toxicity. Since quinone-type metabolites of PCBs and PBDEs can cause neurotoxicity, examples of quinones are also investigated. Condensed Fukui functions are included to analyze local reactivity. These results are important as the reactivity of these compounds helps to explain the toxicity of PCBs and PBDEs. Methods: All DFT computations were performed using Gaussian16 at M06-2x/6–311 + g(2d,p) level of theory without symmetry constraints. Electro-donating (ω-) and electro-accepting (ω +) powers were used as global response functions and condensed Fukui functions as local parameters of reactivity. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) are a group of compounds that, due to their applications, are considered mainly indoor contaminants. To obtain the first information about the presence of PBDEs in Serbia, dust samples (n = 50) were collected in settlements in the northern Serbian province of Vojvodina. The selected/target congeners (BDE-28, 47, 99, 100, 153, 154, and 183) were extracted from house dust by microwave-assisted extraction technique, and purified extracts were analyzed on a dual-column gas chromatograph with micro-electron capture detectors. A wide range of ΣPBDEs was detected (0.295 to 394 ng g−1 dust), which reflects large differences in contamination among the examined homes. For the majority of samples (72%), ΣPBDEs were lower than 5 ng g−1 indicating that people living in Vojvodina province are exposed to low concentrations of PBDEs present in their households. Based on principal component analysis (PCA), balcony areas and age of the house positively correlate with the PBDE congeners with higher detection frequencies (≥ 50%), namely, with BDE-99, BDE-153, and BDE-183. Statistically significant positive correlation (p < 0.01) was obtained for BDE-99 and the number of household's members. Estimated daily intakes (EDItot) were calculated for ingestion and dermal absorption of dust for two age groups—adults and toddlers. These are the first data on PBDE status in the area of the Western Balkan, and the health risk assessment indicates that PBDE levels obtained in household dust do not pose a risk for human health. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) are toxic to organisms with melatonin (MT) providing protection for tissues and cells against these. This study investigates the mechanism of damage of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) and the cellular protection of MT on grass carp hepatocytes. Grass carp hepatocytes were exposed to 25 μmol/L BDE-47 and/or 40 μmol/L MT for 24 h before testing. Acridine orange/ethidium bromide (AO/EB) double fluorescence staining results showed that BDE-47 could induce cell apoptosis. The expression levels of the endoplasmic reticulum (ER) stress-related genes ire1, atf4, grp78, perk, and chop were also significantly up-regulated (P < 0.01). The levels of the apoptosis-related genes caspase3, bax, and caspase9 were significantly up-regulated (P < 0.0001), while the level of bcl-2 was significantly down-regulated (P < 0.01). Compared with the BDE-47 group, the BDE-47 + MT group showed reduced levels of ER and apoptosis of hepatocytes, while the expression of the ER stress-related genes ire1, atf4, grp78, perk, and chop and the apoptosis-related genes caspase3, bax, and caspase9 were down-regulated (P < 0.05), and the level of bcl-2 was up-regulated (P < 0.01). In conclusion, BDE-47 can activate ER and apoptosis in grass carp hepatocytes, while MT can reduce these responses. [ABSTRACT FROM AUTHOR]

Dihydroxylated polybrominated diphenyl ethers (DiOH-PBDEs) could be the metabolites of PBDEs of some organisms or the natural products of certain marine bacteria and algae. OH-PBDEs may demonstrate binding affinity to thyroid hormone receptors (TRs) and can disrupt the functioning of the systems modulated by TRs. However, the thyroid hormone disruption mechanism of diOH-PBDEs remains elusive due to the absence of diOH-PBDEs standards. This investigation explores the potential disruptive effects of OH/diOH-PBDEs on thyroid hormones via competitive binding and coactivator recruitment with TRα and TRβ. At levels of 5000 nM and 25,000 nM, 6-OH-BDE-47 demonstrated significant recruitment of steroid receptor coactivator (SRC), whereas none of the diOH-PBDEs exhibited SRC recruitment within the range of 0.32–25,000 nM. AutoDock CrankPep (ADCP) simulations suggest that the conformation of SRC and TR–ligand complexes, particularly their interaction with Helix 12, rather than binding affinity, plays a pivotal role in ligand agonistic activity. 6,6′-diOH-BDE-47 displayed antagonistic activity towards both TRα and TRβ, while the antagonism of 3,5-diOH-BDE-100 for TRα and TRβ was concentration-dependent. 3,5-diOH-BDE-17 and 3,5-diOH-BDE-51 exhibited no discernible agonistic or antagonistic activities. Molecular docking analysis revealed that the binding energy of 3,3′,5-triiodo-L-thyronine (T3) surpassed that of OH/diOH-PBDEs. 3,5-diOH-BDE-100 exhibited the highest binding energy, whereas 6,6′-diOH-BDE-47 displayed the lowest. These findings suggest that the structural determinants influencing the agonistic and antagonistic activities of halogen phenols may be more intricate than previously proposed, involving factors beyond high-brominated PBDEs or hydroxyl group and bromine substitutions. It is likely that the agonistic or antagonistic propensities of OH/diOH-PBDEs are instigated by protein conformational changes rather than considerations of binding energy. [ABSTRACT FROM AUTHOR]

2,2′,4,4′-Tetrabrominated biphenyl ether (BDE-47) is a polybrominated diphenyl ether (PBDE) homologue that is ubiquitous in biological samples and highly toxic to humans and other organisms. Prior research has confirmed that BDE-47 can induce oxidative damage in RAW264.7 cells, resulting in apoptosis and impaired immune function. The current study mainly focused on how Isoliquiritigenin (ISL) and Licochalcone B (LCB) might protect against BDE-47's immunotoxic effects on RAW264.7 cells. The results show that ISL and LCB could increase phagocytosis, increase the production of MHC-II, and decrease the production of inflammatory factors (TNF-α, IL-6, and IL-1β) and co-stimulatory factors (CD40, CD80, and CD86), alleviating the immune function impairment caused by BDE-47. Secondly, both ISL and LCB could reduce the expressions of the proteins Bax and Caspase-3, promote the expression of the protein Bcl-2, and reduce the apoptotic rate, alleviating the apoptosis initiated by BDE-47. Additionally, ISL and LCB could increase the levels of antioxidant substances (SOD, CAT, and GSH) and decrease the production of reactive oxygen species (ROS), thereby counteracting the oxidative stress induced by BDE-47. Ultimately, ISL and LCB suppress the NF-κB pathway by down-regulating IKBKB and up-regulating IκB-Alpha in addition to activating the Nrf2 pathway and promoting the production of HO-1 and NQO1. To summarize, BDE-47 causes oxidative damage that can be mitigated by ISL and LCB through the activation of the Nrf2 pathway and inhibition of the NF-κB pathway, which in turn prevents immune function impairment and apoptosis. These findings enrich the current understanding of the toxicological molecular mechanism of BDE-47 and the detoxification mechanism of licorice. [ABSTRACT FROM AUTHOR]

Breast milk holds an immense nutritional value as it contains health-promoting substances in a unique, optimal form. Additionally, breast milk's significance extends to health and environmental protection, as it serves as an indicator of both maternal and infant exposure. In this study, breast milk samples collected in 2013 and in 2014–2016 from mothers in Vienna (Austria) were analysed for polybrominated diphenyl ethers (PBDE) and per- and polyfluoroalkyl substances (PFAS), as well as further substances which have been listed under the Stockholm Convention on Persistent Organic Pollutants (POPs) due to their persistent, bioaccumulative and toxic properties. The total concentration of the PBDE congeners in the samples (n = 18, sampled 2013) ranged from 0.055 to 52 ng/g lipid, and from 0.002 to 2.5 ng/g breast milk. In the pooled sample, the sum of PBDEs was detected at a level of 4.4 ng/g lipid. Based on the 2014–2016 study population, certain PFAS were detected in all samples (n = 40). Exposure to the sum of four specific PFAS including perfluorooctanesulphonate (PFOS), perfluorooctanoic acid (PFOA), perfluoro-n-nonanoic acid (PFNA) and perfluoro-1-hexanesulfonate (PFHxS) ranged between 0.014 and 0.12 ng/L breast milk. In the pooled sample, PFOS and PFOA were found in concentrations of 0.025 ng/g and of 0.045 ng/g, respectively. In addition, the first generation of POPs, mainly organochlorine compounds, was measured in a pooled sample of breast milk from participants sampled in 2014–2016 as part of the WHO/UNEP breast milk monitoring program and compared to the POPs measured in pooled samples collected in 1987/1988 and 1992/1993, respectively. Therefore, this paper demonstrates the effectiveness of the Stockholm Convention on POPs by comparing the Austrian results from the WHO/UNEP global breast milk study from 1987 to 2016. However, the data also show that, despite these reductions, health-relevant levels are still being reached, particularly in terms of children's health when the presence of the new generation of POPs, such as PBDEs and PFAS, in human breast milk is taken into account. [ABSTRACT FROM AUTHOR]

Studies have reported health risks associated with seafood contamination, but few data exist on levels in commercially available seafood in the US. To better understand, the magnitude of foodborne exposure and identify vulnerable populations in the US, we measured concentrations of veterinary drugs, persistent organic pollutants (POPs) (polycyclic aromatic hydrocarbons [PAHs], polybrominated diphenyl ethers [PBDEs] and polychlorinated biphenyls [PCBs]), and legacy and current-use pesticides in 46 seafood samples purchased from retail outlets. Measured levels were used to estimate risk based on available maximum residue limits (MRLs) and toxic equivalence (TEQ) factors for analytes. Only seventeen of the 445 analytes were detected, at low substance frequencies. However, half of the samples tested positive for one or more analyte, with total concentrations ranging from below the limit of detection (LOD) to as high as 156 µg/kg wet weight. Based on the risk assessment for individual pesticides and veterinary drugs, the hazard quotients (HQ) were all <1, indicating no risk. However, for the sum of PCB126 and PCB167, two dioxin-like PCBs detected in our samples, the TEQ was nearly two orders of magnitude higher than the WHO limits in one catfish sample. Moreover, vulnerable groups with higher rates of consumption of specific fish types may face higher risks. [ABSTRACT FROM AUTHOR]

As a replacement for polybrominated diphenyl ethers (PBDEs), organophosphorus flame retardants (OPFRs) have been widely used and detected in different indoor environments all over the world. This paper comprehensively describes the concentration levels and distribution information of 11 kinds of OPFRs from 33 indoor dust and 10 air environments, from which TBOEP, TCIPP, and TDCIPP were observed to have higher concentrations in indoor environments. The ΣOPFRs displayed higher concentrations in indoor dust than in indoor air due to the higher molecular weight and vapor pressure of ΣOPFRs in building decoration materials, specifically for TCIPP and TDCIPP compounds. Considering that it is inevitable that people will be exposed to these chemicals in the indoor environments in which they work and live, we estimated their potential health risks through three human exposure pathways and found that the ingestion exposure to TBOEP for toddlers in Japan may reach up to 1270.80 ng/kg/day, which comprises a significant pathway compared to dermal contact and indoor air inhalation. Specifically, the combined total exposure to OPFRs by air inhalation, dust ingestion, and dermal contact was generally below the RfD values for both adults and toddlers, with a few notable higher exposures of some typical OPFRs. [ABSTRACT FROM AUTHOR]

Participants in biomonitoring studies who receive personal exposure reports seek information to reduce exposures. Many chemical exposures are driven by systems-level policies rather than individual actions; therefore, change requires engagement in collective action. Participants' perceptions of collective action and use of report-back to support engagement remain unclear. We conducted virtual focus groups during summer 2020 in a diverse group of peripartum people from cohorts in the Environmental influences on Child Health Outcomes (ECHO) Program (N = 18). We assessed baseline exposure and collective action experience, and report-back preferences. Participants were motivated to protect the health of their families and communities despite significant time and cognitive burdens. They requested time-conscious tactics and accessible information to enable action to reduce individual and collective exposures. Participant input informed the design of digital report-back in the cohorts. This study highlights opportunities to shift responsibility from individuals to policymakers to reduce chemical exposures at the systems level.

Breast milk holds an immense nutritional value as it contains health-promoting substances in a unique, optimal form. Additionally, breast milk’s significance extends to health and environmental protection, as it serves as an indicator of both maternal and infant exposure. In this study, breast milk samples collected in 2013 and in 2014–2016 from mothers in Vienna (Austria) were analysed for polybrominated diphenyl ethers (PBDE) and per- and polyfluoroalkyl substances (PFAS), as well as further substances which have been listed under the Stockholm Convention on Persistent Organic Pollutants (POPs) due to their persistent, bioaccumulative and toxic properties. The total concentration of the PBDE congeners in the samples (n = 18, sampled 2013) ranged from 0.055 to 52 ng/g lipid, and from 0.002 to 2.5 ng/g breast milk. In the pooled sample, the sum of PBDEs was detected at a level of 4.4 ng/g lipid. Based on the 2014–2016 study population, certain PFAS were detected in all samples (n = 40). Exposure to the sum of four specific PFAS including perfluorooctanesulphonate (PFOS), perfluorooctanoic acid (PFOA), perfluoro-n-nonanoic acid (PFNA) and perfluoro-1-hexanesulfonate (PFHxS) ranged between 0.014 and 0.12 ng/L breast milk. In the pooled sample, PFOS and PFOA were found in concentrations of 0.025 ng/g and of 0.045 ng/g, respectively. In addition, the first generation of POPs, mainly organochlorine compounds, was measured in a pooled sample of breast milk from participants sampled in 2014–2016 as part of the WHO/UNEP breast milk monitoring program and compared to the POPs measured in pooled samples collected in 1987/1988 and 1992/1993, respectively. Therefore, this paper demonstrates the effectiveness of the Stockholm Convention on POPs by comparing the Austrian results from the WHO/UNEP global breast milk study from 1987 to 2016. However, the data also show that, despite these reductions, health-relevant levels are still being reached, particularly in terms of children’s health when the presence of the new generation of POPs, such as PBDEs and PFAS, in human breast milk is taken into account.

Groundwater from the communities adjoining Abule Egba (ABE), Epe (EPE), Ikorodu (IKR), Olushosun (OSH) and Solous (SOL) dumpsites in Lagos State, Nigeria, were collected and analyzed for polybrominated diphenyl ethers. Water samples were extracted using liquid-liquid extraction followed by Gas Chromatography/Mass Spectroscopy analysis using the already validated standard method. PBDEs concentrations ranged from 7 ± 10 (IKR) to 78 ± 109 µgL−1 (ABE) for BDE-28; 5.4 ± 0.3 (OSH) to 31.5 ± 27.3 µgL−1 (ABE) for BDE-47; 17 ± 24 (ABE) to 183 ± 226 µgL−1 for BDE-100; 11.7 ± 16.5 (ABE) to 174 ± 217 µgL−1(EPE) for BDE-99; 117 ± 166 (ABE) to 2034 ± 2819 µg L−1 (EPE) for BDE −183; 296 ± 392 (IKR) to 4283 ± 1278 µg L−1 (EPE) for BDE-209. BDE- 153 and BDE- 154 were not detected in all the water samples, while BDE- 28 was only detected in ABE and IKR water samples. The BDE- 209 was the most dominant congener in all the water samples. The cumulative Hazard Index (HI) values for children through ingestion route ranged from 4.95 E + 00 (SOL) to 4.53 E + 01 (EPE), while in adults, it ranged from 4.25 E + 00 (SOL) to 3.88 E + 01 (EPE). This study confirmed the presence of PBDEs at an elevated concentration in groundwater. Since there is no regular supply of pipe-borne water in the study area, residents consume the contaminated groundwater and may be exposed to endocrine-disrupting chemicals. Therefore, the government should provide pipe-borne water for the populace and discourage people from living close to the dumpsites. [ABSTRACT FROM AUTHOR]

Background and Aims: In the global distribution of persistent organic pollutants (POPs) forests play a key role due to the forest canopy effect. In this study, mountain beech forests were selected to identify the level and distribution of selected POPs. Methods: Organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) were analyzed by capillary gas chromatography with an electron capture detector (GC–ECD). Analysis of polychlorinated biphenyls (PCBs) was performed by gas chromatography with a mass spectrometry detector (GC–MS). The polycyclic aromatic hydrocarbons (PAHs) were analyzed by liquid chromatography with a diode array detector (HPLC–DAD). Results: The total ∑20OCP concentrations in the soil from mountain beech forests at a depth of 0 – 40 cm ranged from 24.46 µg kg−1 to 331.11 µg kg−1, and at a depth of 40 – 80 cm from 15.80 µg kg−1 to 247.12 µg kg−1. The mass concentration for ∑6PCB ranges from 9.21 to 95.28 µg kg−1 in the surface soil layer and from 8.07 to 66.56 µg kg−1 in the soil sublayer. The total concentration of ∑7PBDE congeners measured in soil samples from mountain beech forests across Europe was from 1.38 to 29.68 µg kg−1 in the surface soil layer and from 1.01 to 53.31 µg kg−1 in the soil sublayer. The total concentration of ∑16PAH varied from 271.52 to 1154.52 µg kg−1 in the surface soil layer and from 318.95 to 1052.54 µg kg−1 in the soil sublayer. Conclusion: The results of this study can serve as an important basis for international, national, and regional measures of environmental protection of beech forests from POPs pollution. [ABSTRACT FROM AUTHOR]

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The presence of selected polybrominated diphenyl ethers (BDE-28, -47, -99, -100, -153, -154, and -183) was investigated in human milk samples collected from first-time mothers living in Zagreb, capital of Croatia. Samples from 2020 and 2010 were analyzed, and the first temporal comparison between the profiles and levels of these compounds in this area was obtained. A statistically significant difference between mass fractions depending on the sampling year was observed only for BDE-99, with values in 2020 higher than in 2010. BDE-153, whose median value (0.25 and 0.26 ng g−1 lipid weight (l.w.) in 2010 and 2020, respectively) did not decrease in the 10-year period, was the most frequently detected congener in samples from both years. ΣPBDEs ranged from < LOD to 3.53 ng g−1 l.w. (median 0.25 ng g−1 l.w.), and from 0.14 to 6.75 ng g−1 l.w. (median 0.55 ng g−1 l.w.) in 2010 and 2020, respectively. Maternal age and reported fish consumption had no effect on observed PBDE mass fractions, while for BDE-153, positive significant correlation (p > 0.05) was observed of its detected mass fraction with mother's body mass index (BMI) before pregnancy and after childbirth. Infants median estimated daily intake (EDI) via milk ingestion for ΣPBDE was higher in 2020 (3.221 ng kg−1 bw day−1) compared to 2010 (1.429 ng kg−1 bw day−1), but both values were well below threshold value, indicating that human milk consumption in this specific case is unlikely to raise health risks to infants. [ABSTRACT FROM AUTHOR]

Background: Racial and ethnic disparities persist in preterm birth (PTB) and gestational age (GA) at delivery in the United States. It remains unclear whether exposure to environmental chemicals contributes to these disparities. Objectives: We applied recent methodologies incorporating environmental mixtures as mediators in causal mediation analysis to examine whether racial and ethnic disparities in GA at delivery and PTB may be partially explained by exposures to polybrominated diphenyl ethers (PBDEs), a class of chemicals used as flame retardants in the United States. Methods: Data from a multiracial/ethnic US cohort of 2008 individuals with lowrisk singleton pregnancies were utilized, with plasma PBDE concentrations measured during early pregnancy. We performed mediation analyses incorporating three forms of mediators: (1) reducing all PBDEs to a weighted index, (2) selecting a PBDE congener, or (3) including all congeners simultaneously as multiple mediators, to evaluate whether PBDEs may contribute to the racial and ethnic disparities in PTB and GA at delivery, adjusted for potential confounders. Results: Among the 2008 participants, 552 self-identified as non-Hispanic White, 504 self-identified as non-Hispanic Black, 568 self-identified as Hispanic, and 384 self-identified as Asian/Pacific Islander. The non-Hispanic Black individuals had the highest mean ΣPBDEs, the shortest mean GA at delivery, and the highest rate of PTB. Overall, the difference in GA at delivery comparing non-Hispanic Black to non-Hispanic White women was -0.30 (95% CI: -0.54, -0.05) weeks. This disparity reduced to -0.23 (95% CI: -0.49, 0.02) and -0.18 (95% CI: -0.46, 0.10) weeks if fixing everyone's weighted index of PBDEs to the median and the 25th percentile levels, respectively. The proportion of disparity mediated by the weighted index of PBDEs was 11.8%. No statistically significant mediation was found for PTB, other forms of mediator(s), or other racial and ethnic groups. Conclusion: PBDE mixtures may partially mediate the Black vs. White disparity in GA at delivery. While further validations are needed, lowering the PBDEs at the population level might help reduce this disparity. [ABSTRACT FROM AUTHOR]

The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE‐28, ‐47, ‐49, ‐99, ‐100, ‐138, ‐153, ‐154, ‐183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE‐47, ‐99, ‐153, ‐209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint‐specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern. [ABSTRACT FROM AUTHOR]

Here is reported effervescent reaction-enhanced switchable hydrophilic-hydrophobic solvent-based salting-out microextraction (ERSSM) with high-performance liquid chromatography with photodiode array detection (HPLC-PDA) for the preconcentration, extraction, and trace-level determination of polybrominated diphenyl ethers (PBDEs) in milk and water. The important variables were rigorously optimized to be 150 µL of hexanoic acid as the extraction solvent, 400 µL of Na2CO3 as the alkaline source, 350 µL of H2SO4 solution as the acid source, and NaCl as the salting-out agent. The optimized conditions provided a linear range from 0.2 to 50 µg L−1 with limits of detection and quantitation from 0.026 to 0.085 µg L−1 and 0.087 to 0.28 µg L−1 for six PBDEs. The intra-day and inter-day precision values were from 2.48% to 6.75%, and the fortified recoveries for PBDEs were between 78.06% and 103.07% in water and milk samples. The developed procedure avoids the use of a traditional organic disperser and mechanical mixing allowing the determination of PBDEs outdoors by synchronous extraction method and high efficiency for the analytes. These advantages suggest a high potential for the routine monitoring of PBDEs in liquid food and environmental samples. [ABSTRACT FROM AUTHOR]

A series of nano-photocatalysts metal-organic frameworks (MOFs)/graphitic carbon nitride (CN) (named MOFCN- x) with high activity have been synthesized by in-situ growth method. Under visible light irradiation, MOFCN- x hybrids show enhanced photocatalytic activity for the debromination of polybromodiphenyl ethers (PBDEs) compared with CN. Among all the hybrids, MOFCN-2 shows the highest reaction rate, which is 3.3 times as high as that in CN. MOFCN- x photocatalysts own stable visible light activity after recycled experiment. It indicates that a moderate amount of MOFs in MOFCN- x can largely enhance the photocatalytic ability by improved visible light absorption, larger specific surface area and better photo-generated charge carriers separation and transfer capabilities. More interestingly, the debromination pathway of PBDEs by MOFCN- x shows obvious selectivity compared with pure CN that bromines at meta -positions are much more susceptible than those at the para - and ortho -positions. The possible photoreductive mechanism has been proposed. This study shows that nanocomposite MOFCN can be an excellent candidate for dealing with halogen pollutants by solar-driven. [Display omitted] [ABSTRACT FROM AUTHOR]

This document provides a summary of a special issue on molecular toxicology research, focusing on its relevance to cancer prevention. It includes 11 research articles covering various topics such as the effects of smoking on cytokine levels, the impact of nicotine on lung cells, the detection of Aspergillus flavus and aflatoxins in grain crops, the toxicity of polybrominated diphenyl ethers (PBDEs) on immune cells, the mechanisms of intestinal toxicity induced by Euphorbia factors, and the use of maltoside transfection agents to improve adenovirus-mediated cancer gene therapy. The authors hope that these articles will inspire further research in the field of molecular toxicology. [Extracted from the article]

Poly-brominated Di-phenyl Ethers (PBDEs) are important chemical flame retardants, added to many consumer products to reduce the spread of fire. This study was aimed at assessing the bio-accumulation of poly)brominated diphenyl ethers (PBDEs), oxidative stress, and histopathological alterations in Malapterurus electricus from Epe Lagoon, Lagos, Nigeria. Water samples were collected from three different stations of the lagoon and the physiochemical parameters were analyzed using Horiba. Also, fish specimens of Malapterurus electricus were randomly selected from vendors at the Epe Lagoon, Lagos Nigeria. These specimens were then dissected to remove intestine, liver and parasite for examination. The excised liver, intestine and parasite (Electrotaenia malopteruri) were then taken to the laboratory to analyze for bioaccumulation of PBDEs, oxidative stress, and histopathological assessment. Results showed that the physico-chemical parameters of water body had their mean values either below or within established permissible limits. BDE-183 had the highest concentration accumulated in the liver meanwhile BDE-209 congener was not detected at all across the intestine, liver and parasite. The oxidative stress response parameters, GPx (glutathione peroxidase) was highest for both intestine and liver, GPx, and SOD (superoxide dismutase) were higher in the uninfected fish than the infected one. Histopathological findings in the uninfected fish showed normal villi structure, normal mucosa, sub)mucosa, and muscularis while the infected fish showed a mild increase in the connective tissue of the sub-mucosa and a focal area of loss of villous structure. The results reflect the biological effects of PBDEs pollution on the aquatic organisms and in combination with oxidative stress markers and histopathology of the guts; the endangered state of the Epe lagoon was unveiled. [ABSTRACT FROM AUTHOR]

The soil-air exchange behavior of persistent organic pollutants (POPs) plays a significant role in the distribution and fate in the two phases. This paper summarizes the selective behaviors of typical POPs contaminants and their homologues and isomers in soil-air exchange from the four aspects: sampling techniques, fugacity models, exchange directions and fluxes, as well as influencing factors. Dichlorodiphenyltrichloroethane (DDTs) and their metabolites o, p'-DDT ... p,p.-DDD show the trend of net deposition from various studies. α-, β- hexachlorocyclohexane (HCHs) prefers to migrate from soil to atmosphere than γ-, δ- HCH. Polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) with lower molecular weight compounds are generally volatilized to the atmosphere. Polybrominated diphenyl ethers (PBDEs) with low bromination degree have higher liquidity. Compared with other organophosphorus flame retardants, tributyl phosphate has a higher volatilization trend. For the novel pollutants, the exchange fluxes of perfluorooctanesulfonate (PFOS) and short-/medium-chain chlorinated paraffins (CPs) have been reported. The direction of soil-air exchange is also affected by temperature and soil organic carbon content. [ABSTRACT FROM AUTHOR]

The present laboratory study (96 hours and 30 days) aimed to provide for the first time the possible adverse effects of different concentrations of PBDEs congers (PBDE 28, PBDE 47, PBDE 99, PBDE 100, PBDE 153, PBDE 154) based on Water Framework Directive 2000/60/EC (WFD) in zebra mussel (Dreissena polymorpha Pallas, 1771). Therefore, we analysed the gill histochemical structure by applying the Periodic acid-Schiff staining method to assess the exposed individuals' physiological status and linked them to the tested PBDEs concentrations in the contaminated water. [ABSTRACT FROM AUTHOR]

POP data are limited in the marine environment; thus, this study aimed to investigate background persistent organic pollutant (POP) levels in oceanic deep-water-deposited particulates in the South China Sea (SCS). Six POPs, including polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (DL-PCBs), polybrominated diphenyl ethers (PBDEs), polybrominated dibenzo-p-dioxins/dibenzofurans (PBDD/Fs), polychlorinated diphenyl ethers (PCDEs), and polybrominated biphenyls (PBBs), were investigated in eight pooled samples from the SCS from 20 September 2013 to 23 March 2014 and 15 April 2014 to 24 October 2014 at depths of 2000 m and 3500 m. PBDEs were the most predominant compounds, with the highest mean Σ14PBDE of 125 ± 114 ng/g dry weight (d.w.), followed by Σ17PCDD/F, Σ12PBDD/F, and Σ12DL-PCB (275 ± 1930, 253 ± 216, and 116 ± 166 pg/g d.w., respectively). Most PBDD/F, PBB, and PCDE congeners were below the detection limits. PCDDs had the highest toxic equivalency (TEQ), followed by PBDDs and DL-PCBs. Among the six POPs, PBDEs were the major components of the marine-deposited particles, regarding both concentrations and mass fluxes. Compared to 3500 m, PBDE levels were higher at a depth of 2000 m. PBDE mass fluxes were 20.9 and 14.2 ng/m2/day or 68.2 and 75.9 ng/m2/year at deep-water 2000 and 3500 m, respectively. This study first investigated POP levels in oceanic deep-water-deposited particles from existing global data. [ABSTRACT FROM AUTHOR]

To overcome ethical and technical challenges impeding the study of human dermal uptake of chemical additives present in microplastics (MPs), we employed 3D human skin equivalent (3D-HSE) models to provide first insights into the dermal bioavailability of polybrominated diphenyl ether (PBDEs) present in MPs; and evaluated different factors influencing human percutaneous absorption of PBDEs under real-life exposure scenario. PBDEs were bioavailable to varying degrees (up to 8 % of the exposure dose) and percutaneous permeation was evident, albeit at low levels (≤0.1 % of the exposure dose). While the polymer type influenced the release of PBDEs from the studied MPs to the skin, the polymer type was less important in driving the percutaneous absorption of PBDEs. The absorbed fraction of PBDEs was strongly correlated (r2 = 0.88) with their water solubility, while the dermal permeation coefficient Papp of PBDEs showed strong association with their molecular weight and logKOW. More sweaty skin resulted in higher bioavailability of PBDEs from dermal contact with MPs than dry skin. Overall, percutaneous absorption of PBDEs upon skin contact with MPs was evident, highlighting, for the first time, the potential significance of the dermal pathway as an important route of human exposure to toxic additive chemicals in MPs.