Toxic effects of decabromodiphenyl ether (BDE-209) on human embryonic kidney cells

Nano‑selenium alleviates the pyroptosis of cardiovascular endothelial cells in chicken induced by decabromodiphenyl ether through ERS-TXNIP-NLRP3 pathway

Decabromodiphenyl ether (BDE-209) is one of the most widely used flame retardants that can infect domestic and wildlife through contaminated feed. Nano‑selenium (Nano-Se) has the advantage of enhancing the anti-oxidation of cells. Nonetheless, it remains uncertain whether Nano-Se can alleviate vascular Endothelial cells damage caused by BDE-209 exposure in chickens. Therefore, we established a model with 60 1-day-old chickens, and administered BDE-209 intragastric at a ratio of 400 mg/kg bw/d, and mixed Nano-Se intervention at a ratio of 1 mg/kg in the feed. The results showed that BDE-209 could induce histopathological and ultrastructural changes. Additionally, exposure to BDE-209 led to cardiovascular endoplasmic reticulum stress (ERS), oxidative stress and thioredoxin-interacting protein (TXNIP)-pyrin domain-containing protein 3 (NLRP3) pathway activation, ultimately resulting in pyroptosis. Using the ERS inhibitor 4-PBA in Chicken arterial endothelial cells (PAECs) can significantly reverse these changes. The addition of Nano-Se can enhance the body's antioxidant capacity, inhibit the activation of NLRP3 inflammasome, and reduce cellular pyroptosis. These results suggest that Nano-Se can alleviate the pyroptosis of cardiovascular endothelial cells induced by BDE-209 through ERS-TXNIP-NLRP3 pathway. This study provides new insights into the toxicity of BDE-209 in the cardiovascular system and the therapeutic effects of Nano-Se.

A critical review on BDE-209: Source, distribution, influencing factors, toxicity, and degradation

As the most widely used polybrominated diphenyl ether, BDE-209 is commonly used in polymer-based commercial and household products. Due to its unique physicochemical properties, BDE-209 is ubiquitous in a variety of environmental compartments and can be exposed to organisms in various ways and cause toxic effects. The present review outlines the current state of knowledge on the occurrence of BDE-209 in the environment, influencing factors, toxicity, and degradation. BDE-209 has been detected in various environmental matrices including air, soil, water, and sediment. Additionally, environmental factors such as organic matter, total suspended particulate, hydrodynamic, wind, and temperature affecting BDE-209 are specifically discussed. Toxicity studies suggest BDE-209 may cause systemic toxic effects on living organisms, reproductive toxicity, embryo-fetal toxicity, genetic toxicity, endocrine toxicity, neurotoxicity, immunotoxicity, and developmental toxicity, or even be carcinogenic. BDE-209 has toxic effects on organisms mainly through epigenetic regulation and induction of oxidative stress. Evidence regarding the degradation of BDE-209, including biodegradation, photodegradation, Fenton degradation, zero-valent iron degradation, chemical oxidative degradation, and microwave radiation degradation is summarized. This review may contribute to assessing the environmental risks of BDE-209 to help develop rational management plans.

Cellular and physiological mechanisms of halogenated and organophosphorus flame retardant toxicity

Flame retardants (FRs) are chemical substances used to inhibit the spread of fire in numerous industrial applications, and their abundance in modern manufactured products in the indoor and outdoor environment leads to extensive direct and food chain exposure of humans. Although once considered relatively non-toxic, FRs are demonstrated by recent literature to have disruptive effects on many biological processes, including signaling pathways, genome stability, reproduction, and immune system function. This review provides a summary of research investigating the impact of major groups of FRs, including halogenated and organophosphorus FRs, on animals and humans in vitro and/or in vivo. We put in focus those studies that explained or referenced the modes of FR action at the level of cells, tissues and organs. Since FRs are highly hydrophobic chemicals, their biophysical and biochemical modes of action usually involve lipophilic interactions, e.g. with biological membranes or elements of signaling pathways. We present selected toxicological information about these molecular actions to show how they can lead to damaging membrane integrity, damaging DNA and compromising its repair, changing gene expression, and cell cycle as well as accelerating cell death. Moreover, we indicate how this translates to deleterious bioactivity of FRs at the physiological level, with disruption of hormonal action, dysregulation of metabolism, adverse effects on male and female reproduction as well as alteration of normal pattern of immunity. Concentrating on these subjects, we make clear both the advances in knowledge in recent years and the remaining gaps in our understanding, especially at the mechanistic level.

Assessment of five typical environmental endocrine disruptors and thyroid cancer risk: a meta-analysis

Introduction

There are conflicting reports on the association between environmental endocrine disruptors (EEDs) and thyroid cancer. This meta-analysis aimed to elucidate the relationship between EEDs and thyroid cancer.

Methods

We searched for epidemiological studies on EEDs and thyroid cancer published in PubMed and Web of Science up to December 2022. We then screened the articles that could extract data on EEDs concentration levels in both thyroid cancer patients and healthy controls. We excluded articles that could not calculate effect sizes, focused on other thyroid diseases, or lacked controls. Standardized mean difference (SMD) was calculated to analyze the association between EEDs and thyroid cancer. We measured the heterogeneity among the included studies using I2, assessed publication bias by Egger's and Begg's test, and evaluated article quality using the Newcastle-Ottawa Quality Score (NOS). In the end, fifteen eligible case-control studies were included.

Results

Our comprehensive analysis revealed that polychlorinated biphenyls (PCBs) were negatively associated with thyroid cancer{ SMD = -0.03, 95% confidence interval (CI) = (-0.05, -0.00), P = 0.03}, while polybrominated diphenyl ethers (PBDEs), phthalates (PAEs), and heavy metals were positively associated with thyroid cancer{PBDEs: SMD = 0.14, 95%CI = (0.04, 0.23), P = 0.007; PAEs: SMD = 0.30, 95%CI = (0.02, 0.58), P = 0.04; heavy metals: SMD = 0.21, 95%CI = (0.11, 0.32), P < 0.001}. We did not find a statistically significant relationship between bisphenol A (BPA) and thyroid cancer. Most of the included studies did not show publication bias, except for those on PCBs.

Discussion

Our results indicate that exposure to certain EEDs, such as PBDEs, PAEs, and heavy metals, increases the risk of thyroid cancer. However, further large-scale epidemiological studies and mechanism studies are needed to verify these potential relationships and understand the underlying biological mechanisms.

The thermal degradation and soil recovery of thermal treatment of field-weathered decabrominated diphenyl ether-contaminated soil

A farm at Taoyuan in Taiwan was highly contaminated with decabrominated diphenyl ether (BDE-209), a widely used commercial brominated flame retardant and persistent in the environment, more than 10 years. Since crops are able to absorb and accumulate BDE-209 from soils in our previous research, posing a hazardous risk for humans, it is essential to develop a practical method of soil treatment. Thermal treatment was studied among different approaches. In our previous study (Ko et al., 2022), we found that heating to 450 °C for 30 min achieved a complete removal of BDE-209 in soil. However, the high temperature significantly decreased the original soil organic matter (SOM) from 2.47% to 0.27%, altering the soil texture, damaging microbial biomass, and thus affecting the revegetation after the thermal treatment. Sugarcane bagasse, a common agricultural residue, served as an amendment to restore soil fertility. Current results indicate that 2.5% bagasse can improve the SOM in soil by up to 2.73% and restore its bacterial composition, making the plant growth conditions similar to those of the untreated contaminated soil. In light of the high removal efficiency provided by the 450°C-thermal treatment and the high recovery efficiency of sugarcane bagasse, the strategy presented in this study serves to be a promising method for sustainable remediation.

Associations between serum polychlorinated biphenyls, halogen flame retardants, and renal function indexes in residents of an e-waste recycling area

E-waste handling activities release large quantities of polychlorinated biphenyls (PCBs) and halogen flame retardants (HFRs) into the surrounding area, creating a high exposure risk for local residents. However, the possibility of PCBs and HFRs exposure contributing to renal injury has not been extensively studied. To fill this knowledge gap, we conducted an epidemiological analysis of adolescents and adults recruited from an e-waste recycling area and a control area. Some PCBs and HFRs compounds were statistically significantly associated with the levels of β₂-microglobulin (β₂-MG), blood urea nitrogen (BUN), serum creatinine (SCr), and uric acid, with thyroid hormone-related genes found to partly mediate these associations. The interactions of PCBs and HFRs with metals also influenced renal function indexes. Exposure to high concentrations of PCBs and HFRs resulted in higher levels of β₂-MG and lower levels of BUN and SCr in the exposed group. As indicated by the elevated β₂-MG levels, high exposure to PCBs and HFRs may increase the risk of early renal injury for adolescents. These findings help to clarify the impacts of PCBs and HFRs on renal function and highlight the need to protect the health of residents in regions impacted by e-waste handling activities.

Exposure to Polybrominated Diphenyl Ether Flame Retardants Causes Deoxyribonucleic Acid Damage in Human Thyroid Cells In Vitro

INTRODUCTION

The incidence of papillary thyroid cancer (PTC) in the United States has tripled in the past 30 y. Polybrominated diphenyl ethers (PBDEs) are flame retardants that were ubiquitously used over that time period, and exposure to PBDEs has been associated with PTC prevalence. They are potential carcinogens via their induction of reactive oxygen species (ROS) formation and resultant deoxyribonucleic acid (DNA) damage. We sought to determine the effects of PBDE and tris(2-chloroethyl) phosphate (TCEP), another flame retardant implicated in PTC incidence, on thyrocytes in vitro and measure PBDE levels in human thyroid tissue to determine their carcinogenic potential.

METHODS

Nthy-Ori, an immortalized benign human thyroid follicular cell line was used as a model of normal human thyroid. MTT assays were used to measure cell viability after exposure to PBDEs and TCEP. ROS levels and double-stranded and single-stranded DNA breaks were measured to determine genotoxicity. DNA damage response protein levels were measured with immunoblotting.

RESULTS

Exposure to 20μM PBDE or TCEP for 48 h had minimal effects on thyrocyte viability. There was no significant increase in intracellular ROS up to 6 h following PBDE or TCEP exposure in thyrocytes; however, cells exposed to PBDE 47 showed evidence of DNA single-stranded and double-stranded breaks. There was a dose-dependent increase in γH2AX levels following exposure to PBDEs 47 and 209 in Nthy-Ori cells but not with TCEP treatment.

CONCLUSIONS

PBDE 47 and 209 demonstrated genotoxicity but not cytotoxicity in follicular thyrocytes in vitro. Therefore, PBDE 47 and 209 may be carcinogenic in human thyroid cells.

Modulating the Ubiquitin–Proteasome System: A Therapeutic Strategy for Autoimmune Diseases

Multiple sclerosis (MS) is an autoimmune, neurodegenerative disease associated with the central nervous system (CNS). Autoimmunity is caused by an abnormal immune response to self-antigens, which results in chronic inflammation and tissue death. Ubiquitination is a post-translational modification in which ubiquitin molecules are attached to proteins by ubiquitinating enzymes, and then the modified proteins are degraded by the proteasome system. In addition to regulating proteasomal degradation of proteins, ubiquitination also regulates other cellular functions that are independent of proteasomal degradation. It plays a vital role in intracellular protein turnover and immune signaling and responses. The ubiquitin–proteasome system (UPS) is primarily responsible for the nonlysosomal proteolysis of intracellular proteins. The 26S proteasome is a multicatalytic adenosine-triphosphate-dependent protease that recognizes ubiquitin covalently attached to particular proteins and targets them for degradation. Damaged, oxidized, or misfolded proteins, as well as regulatory proteins that govern many essential cellular functions, are removed by this degradation pathway. When this system is affected, cellular homeostasis is altered, resulting in the induction of a range of diseases. This review discusses the biochemistry and molecular biology of the UPS, including its role in the development of MS and proteinopathies. Potential therapies and targets involving the UPS are also addressed.

A meta-analysis of factors influencing concentrations of brominated flame retardants and organophosphate esters in indoor dust

Current assessments of human exposure to flame retardants (FRs) via dust ingestion rely on measurements of FR concentrations in dust samples collected at specific points in time and space. Such exposure assessments are rendered further uncertain by the possibility of within-room and within-building spatial and temporal variability, differences in dust particle size fraction analysed, as well as differences in dust sampling approach. A meta-analysis of peer-reviewed data was undertaken to evaluate the impact of these factors on reported concentrations of brominated flame retardants (BFRs) and organophosphate esters (OPEs) in dust and subsequent human exposure estimates. Except for a few cases, concentrations of FRs in elevated surface dust (ESD) exceeded significantly those in floor dust (FD). The implications of this for exposure assessment are not entirely clear. However, they imply that analysing FD only will underestimate exposure for adults who likely rarely ingest floor dust, while analysing ESD only would overestimate exposure for toddlers who likely rarely ingest elevated surface dust. Considerable within-building spatial variability was observed with no specific trend between concentrations of either BFRs or OPEs in living rooms and bedrooms in the same homes, implying that exposure assessments based solely on sampling one room are uncertain. Substantial differences in FR concentrations were observed in different particle size fractions of dust. This is likely partly attributable to the presence of abraded polymer particles/fibres with high FR concentrations in larger particle size fractions. This has implications for exposure assessment as adherence to skin and subsequent FR uptake via ingestion and dermal sorption varies with particle size. Analysing dust samples obtained from a householder vacuum cleaner (HHVC) compared with researcher collected dust (RCD) will underestimate human exposure to the most of studied contaminants. This is likely due to the losses of volatile FRs from HHVC dust over the extended period such dust spends in the dust bag. Temporal variability in FR concentrations is apparent during month-to-month or seasonal monitoring, with such variability likely due more to changes in room contents rather than seasonal temperature variation.

Inevitable human exposure to emissions of polybrominated diphenyl ethers: A perspective on potential health risks

Polybrominated diphenyl ethers (PBDEs) serve as flame retardants in many household materials such as electrical and electronic devices, furniture, textiles, plastics, and baby products. Though the use of PBDEs like penta-, octa- and deca-BDE greatly reduces the fire damage, indoor pollution by these toxic emissions is ever-growing. In fact, a boom in the global market projections of PBDEs threatens human health security. Therefore, efforts are made to minimize PBDEs pollution in USA and Europe by encouraging voluntary phasing out of the production or imposing compelled regulations through Stockholm Convention, but >500 kilotons of PBDEs still exist globally. Both 'environmental persistence' and 'bioaccumulation tendencies' are the hallmarks of PBDE toxicities; however, both these issues concerning household emissions of PBDEs have been least addressed theoretically or practically. Critical physiological functions, lipophilicity and toxicity, trophic transfer and tissue specificities are of utmost importance in the benefit/risk assessments of PBDEs. Since indoor debromination of deca-BDE often yields many products, a better understanding on their sorption propensity, environmental fate and human toxicities is critical in taking rigorous measures on the ever-growing global deca-BDE market. The data available in the literature on human toxicities of PBDEs have been validated following meta-analysis. In this direction, the intent of the present review was to provide a critical evaluation of the key aspects like compositional patterns/isomer ratios of PBDEs implicated in bioaccumulation, indoor PBDE emissions versus human exposure, secured technologies to deal with the toxic emissions, and human toxicity of PBDEs in relation to the number of bromine atoms. Finally, an emphasis has been made on the knowledge gaps and future research directions related to endurable flame retardants which could fit well into the benefit/risk strategy.

Characterization of a Sequential UV Photolysis-Biodegradation Process for Treatment of Decabrominated Diphenyl Ethers in Sorbent/Water Systems

Decabrominated diphenyl ether (BDE-209) is a primary component of the brominated flame retardants used in a variety of industrial and domestic applications. BDE-209 bioaccumulates in aquatic organisms and has been identified as an emerging contaminant that threatens human and ecosystem health. Sequential photolysis-microbial biodegradation processes were utilized here to treat BDE-209 in clay- or soil-water slurries. The removal efficiency of BDE-209 in the clay-water slurries was high; i.e., 96.5%, while that in the soil-water slurries was minimal. In the clay-water slurries the first order rate constants for the UV photolysis and biodegradation of BDE-209 were 0.017 1/day and 0.026 1/day, respectively. UV wavelength and intensity strongly influenced the BDE-209 photolysis and the subsequent biodegradation of photolytic products. Facultative chemotrophic bacteria, including Acidovorax spp., Pseudomonas spp., Novosphingobium spp. and Sphingomonas spp., were the dominant members of the bacterial community (about 71%) at the beginning of the biodegradation; many of these organisms have previously been shown to biodegrade BDE-209 and other polybrominated diphenyl ether (PBDE) congeners. The Achromobacter sp. that were isolated (NH-2; NH-4; NH-6) were especially effective during the BDE-209 degradation. These results indicated the effectiveness of the sequential UV photolysis and biodegradation for treating certain BDE-209-contaminated solids; e.g., clays; in bioreactors containing such solids as aqueous slurries. Achieving a similar treatment effectiveness for more heterogeneous solids containing natural organic matter, e.g., surface solids, appears to be significantly more difficult. Further investigations are needed in order to understand the great difference between the clay-water or soil-water slurries.

Epigenetic Effects of Polybrominated Diphenyl Ethers on Human Health

Disruption of epigenetic regulation by environmental toxins is an emerging area of focus for understanding the latter's impact on human health. Polybrominated diphenyl ethers (PBDEs), one such group of toxins, are an environmentally pervasive class of brominated flame retardants that have been extensively used as coatings on a wide range of consumer products. Their environmental stability, propensity for bioaccumulation, and known links to adverse health effects have evoked extensive research to characterize underlying biological mechanisms of toxicity. Of particular concern is the growing body of evidence correlating human exposure levels to behavioral deficits related to neurodevelopmental disorders. The developing nervous system is particularly sensitive to influence by environmental signals, including dysregulation by toxins. Several major modes of actions have been identified, but a clear understanding of how observed effects relate to negative impacts on human health has not been established. Here, we review the current body of evidence for PBDE-induced epigenetic disruptions, including DNA methylation, chromatin dynamics, and non-coding RNA expression while discussing the potential relationship between PBDEs and neurodevelopmental disorders.

A bibliometric analysis of investigations of polybrominated diphenyl ethers (PBDEs) in biological and environmental matrices from 1992 - 2018

The aim of this bibliometric analysis is to review the status and research evolution on the analysis of polybrominated diphenyl ethers (PBDEs) on biological and environmental matrices from January 1992 to February 2018 in the Web of Science focusing on original articles and reviews. One thousand four hundred and eighty two articles were found in the databases of the Web of Science on the analysis of PBDEs. Quantitative and qualitative parameters (countries, number of articles, frequency, average article citations and total average citations) were used to analyse each article and ranking of countries based on productivity, authors and article citation. Complementary analysis based on keywords was also done. The last decade experienced an increase in the analysis of this pollutant with the year 2012 recording the highest number of published articles (n = 137). High rate of collaboration with a very rich research network exists amongst institutions in Asian, European and America countries. China and USA are ranked 1st and 2nd on countries based on productivity, publishing 30% and 21.7% of the total articles respectively. South Africa was the only African country found in the category of countries based on productivity occupying the 17th position. The spectacular growth of research by researchers domiciled in China suggests the dominance of China in scientific research. This study suggests high research interest on this class of pollutant in developed countries. Additionally, lack of funds and sophisticated analytical tools may be responsible for lack of PBDEs-related studies in developing countries especially in Africa.

Assessing Binary Mixture Effects from Genotoxic and Endocrine Disrupting Environmental Contaminants Using Infrared Spectroscopy

Benzo[a]pyrene (B[a]P), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) are persistent contaminants and concern has arisen over co-exposure of organisms when the chemicals exist in mixtures. Herein, attenuated total reflection Fourier transform infrared spectroscopy was used to identify biochemical alterations induced in cells by single and binary mixtures of these environmental chemicals. It was also investigated as a method to identify if interactions are occurring in mixtures and as a possible tool to predict mixture effects. Mallard fibroblasts were treated with single and binary mixtures of B[a]P, PCB126, PCB153, BDE47, and BDE209. Comparison of observed spectra from cells treated with binary mixtures with expected additive spectra, which were created from individual exposure spectra, indicated that in many areas of the spectrum, less-than-additive binary mixture effects may occur. However, possible greater-than-additive alterations were identified in the 1650-1750 cm^-1 lipid region and may demonstrate a common mechanism of B[a]P and PCBs or PBDEs, which can enhance toxicity in mixtures.

Within-room and within-home spatial and temporal variability in concentrations of legacy and "novel" brominated flame retardants in indoor dust

To test the hypothesis that assessments of human exposure to PBDEs and NBFRs (PBEB, EH-TBB, BEH-TEBP, BTBPE and DBDPE) via dust ingestion should take into account spatial and temporal variability in dust contamination; 238 dust samples were collected from nine different rooms within three homes in Birmingham UK. In each room, three different dust samples were taken at monthly intervals for nine months, one sample from elevated surfaces and two samples from two different floor areas. Substantial within-room and within-home spatial variability in BFR concentrations was apparent between two floor areas and between different rooms due to the varying distances of sampled surfaces from potential BFR sources. With the exception of DBDPE, BFR concentrations in elevated surface dust exceeded significantly those in floor dust. Considerable within-room and within-home temporal variability in BFR concentrations was also apparent over a nine month sampling period. This is likely attributable to changes in room contents. Based on observed spatial and temporal variability, exposure estimates based on analysis of a single dust sample taken from one specific floor area at one specific point in time may not be entirely representative of human exposure in that room. Noticeable variability in BFR concentrations was also observed between colder and warmer seasons. In 13 out of 17 floor areas, concentrations of Σ₈tri-deca-BDEs were higher in colder seasons, while those of Σ₅NBFRs were higher in warmer seasons. Significant negative correlation was observed in two rooms between concentrations of BDE-99, Σ₇tri-hepta-BDEs and BEH-TEBP and dust loading (g/m²).

Selective extraction of bisphenol A from water by one-monomer molecularly imprinted magnetic nanoparticles

One-monomer molecularly imprinted magnetic nanoparticles were prepared as adsorbents for selective extraction of bisphenol A from water in this study. A single bi-functional monomer was adopted for preparation of the molecularly imprinted polymer, avoiding the tedious trial-and-error optimizations as traditional strategy. Moreover, bisphenol F was used as the dummy template for bisphenol A to avoid the interference from residual template molecules. These nanoparticles showed not only large adsorption capacity and good selectivity to the bisphenol A but also outstanding magnetic response performance. Furthermore, they were successfully used as magnetic solid-phase extraction adsorbents of bisphenol A from various water samples, including tap water, river water, and seawater. The developed method was found to be much more efficient, convenient, and economical for selective extraction of bisphenol A compared with the traditional solid-phase extraction. Separation of these nanoparticles can be easily achieved with an external magnetic field, and the optimized adsorption time was only 15 min. The recoveries of bisphenol A in different water samples ranged from 85.38 to 93.75%, with relative standard deviation lower than 7.47%. These results showed that one-monomer molecularly imprinted magnetic nanoparticles had the potential to be popular adsorbents for selective extraction of pollutants from water.

A flexible plasma-treated silver-nanowire electrode for organic light-emitting devices

Silver nanowires (AgNWs) are a promising candidate to replace indium tin oxide (ITO) as transparent electrode material. However, the loose contact at the junction of the AgNWs and residual surfactant polyvinylpyrrolidone (PVP) increase the sheet resistance of the AgNWs. In this paper, an argon (Ar) plasma treatment method is applied to pristine AgNWs to remove the PVP layer and enhance the contact between AgNWs. By adjusting the processing time, we obtained AgNWs with a sheet resistance of 7.2Ω/□ and a transmittance of 78% at 550 nm. To reduce the surface roughness of the AgNWs, a peel-off process was used to transfer the AgNWs to a flexible NOA63 substrate. Then, an OLED was fabricated with the plasma-treated AgNWs electrode as anode. The highest brightness (27000 cd/m²) and current efficiency (11.8 cd/A) was achieved with a 30 nm thick light emitting layer of tris-(8-hydroxyquinoline) aluminum doped with 1% 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5 H,11H-(1)-benzopyropyrano(6,7-8-I,j)quinolizin-11-one. Compared to thermal annealing, the plasma-treated AgNW film has a lower sheet resistance, a shorter processing time, and a better hole-injection. Our results indicate that plasma treatment is an effective and efficient method to enhance the conductivity of AgNW films, and the plasma-treated AgNW electrode is suitable to manufacture flexible organic optoelectronic devices.

Perinatal exposure to organohalogen pollutants decreases vasopressin content and its mRNA expression in magnocellular neuroendocrine cells activated by osmotic stress in adult rats

Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are environmental pollutants that produce neurotoxicity and neuroendocrine disruption. They affect the vasopressinergic system but their disruptive mechanisms are not well understood. Our group reported that rats perinatally exposed to Aroclor-1254 (A1254) and DE-71 (commercial mixtures of PCBs and PBDEs) decrease somatodendritic vasopressin (AVP) release while increasing plasma AVP responses to osmotic activation, potentially emptying AVP reserves required for body-water balance. The aim of this research was to evaluate the effects of perinatal exposure to A1254 or DE-71 (30mgkg/day) on AVP transcription and protein content in the paraventricular and supraoptic hypothalamic nuclei, of male and female rats, by in situ hybridization and immunohistochemistry. cFOS mRNA expression was evaluated in order to determine neuroendocrine cells activation due to osmotic stimulation. Animal groups were: vehicle (control); exposed to either A1254 or DE-71; both, control and exposed, subjected to osmotic challenge. The results confirmed a physiological increase in AVP-immunoreactivity (AVP-IR) and gene expression in response to osmotic challenge as reported elsewhere. In contrast, the exposed groups did not show this response to osmotic activation, they showed significant reduction in AVP-IR neurons, and AVP mRNA expression as compared to the hyperosmotic controls. cFOS mRNA expression increased in A1254 dehydrated groups, suggesting that the AVP-IR decrease was not due to a lack of the response to the osmotic activation. Therefore, A1254 may interfere with the activation of AVP mRNA transcript levels and protein, causing a central dysfunction of vasopressinergic system.

Influence of sampling approach on concentrations of legacy and "novel" brominated flame retardants in indoor dust

The study investigates the impact of sampling method on the concentrations of PBDEs (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209) and NBFRs (PBEB, EH-TBB, BEH-TEBP, BTBPE and DBDPE) in indoor dust. A total of 36 dust samples were collected from 12 homes in Birmingham, UK (3 samples per home comprising researcher collected dust - both RCD from the living room (RCDL) and bedroom (RCDB), with an additional householder vacuum dust sample - HHVD). BDE-209 was the predominant compound, with average concentrations of 2642, 2336 and 2634 ng/g in RCDL, RCDB and HHVD respectively. The next most abundant BFR was BEH-TEBP, followed by DBDPE, with average concentrations of 306, 339 and 233 ng/g for BEH-TEBP and 155, 91 and 152 ng/g for DBDPE in RCDL, RCDB and HHVD respectively. Average concentrations of Σ₆tri-hexa-BDEs were 47, 41, and 24 ng/g in RCDL, RCDB and HHVD respectively. With the exception of Σ₆tri-hexa-BDEs, BDE-153, BDE-99 and to some extent BEH-TEBP, no significant differences were found between BFR concentrations in RCD and HHVD. Statistically significant correlations were observed between concentrations of Σ₆tri-hexa-BDEs, BEH-TEBP and DBDPE in HHVD and in both RCDL and RCDB. However, comparison of estimates of exposure via dust ingestion based on these two sampling methods revealed that using householder vacuum dust underestimates exposure, particularly for Σ₆tri-hexa-BDEs, and to some extent for BEH-TEBP. In contrast, HHVD could be a viable alternative to RCD as a metric of exposure for higher brominated BFRs.

Biodegradation of Decabromodiphenyl Ether (BDE-209) by Crude Enzyme Extract from Pseudomonas aeruginosa

The biodegradation effect and mechanism of decabromodiphenyl ether (BDE-209) by crude enzyme extract from Pseudomonas aeruginosa were investigated. The results demonstrated that crude enzyme extract exhibited obviously higher degradation efficiency and shorter biodegradation time than Pseudomonas aeruginosa itself. Under the optimum conditions of pH 9.0, 35 °C and protein content of 2000 mg/L, 92.77% of the initial BDE-209 (20 mg/L) was degraded after 5 h. A BDE-209 biodegradation pathway was proposed on the basis of the biodegradation products identified by GC-MS analysis. The biodegradation mechanism showed that crude enzyme extract degraded BDE-209 into lower brominated PBDEs and OH-PBDEs through debromination and hydroxylation of the aromatic rings.