Concentrations Of Brominated Flame Retardants Research Articles

Associations between exposure to brominated flame retardants and periodontitis in U.S. adults

BackgroundIncreasing evidence has shown that environmental factors play a crucial role in the pathogenesis of periodontitis. Humans are simultaneously exposed to a variety of environmental brominated flame retardants (BFRs). However, the relationship between BFRs in periodontitis remains unclear. This study aimed to investigate the overall association between BFRs and periodontitis in a nationally representative US population and to further identify important chemicals. MethodsData from 3322 NHANES participants from 2009 to 2016 were used. Serum BFRs were registered, including PBDE-28, PBDE-47, PBDE-85, PBDE-99, PBDE100, PBDE-153, PBDE-154, PBDE-183, PBDE-209 and PBB-153. Survey weighted generalized logistic regression models, restricted cubic splines (RCS) were conducted to assess single BFRs exposure with periodontitis. Meanwhile, weighted quantile sum (WQS) regression and Bayesian kernel machine regression (BKMR) were used to evaluate the overall association of BFRs mixtures with periodontitis and to identify significant chemicals. ResultsA total of 3322 participants were included in the study, of whom 1795 had periodontitis. After adjusting for potential confounders, multiple logistic regression analysis revealed significant positive associations between serum levels of PBDE-28, PBDE-47, PBDE-85, PBDE-99, PBDE-100, PBDE-154, PBDE-183, and PBB-153 and the risk of periodontitis (all P < 0.05). A dose-response relationship was observed for many of these BFRs, with higher quantiles associated with an increased risk of periodontitis. WQS regression identified PBDE-183 (38.60%), PBDE-153 (21.20%), PBDE-209 (14.40%), and PBDE-99 (11.90%) as the BFRs with the largest weights contributing to the overall mixture effect on periodontitis risk. BKMR analysis further supported the positive association between serum BFRs and periodontitis, with most individual BFRs showing a positive trend, except for PBDE-153. Restricted cubic spline analysis revealed a generally increasing probability of periodontitis with increasing concentrations of BFRs, albeit with some nonlinear patterns for certain compounds. ConclusionIn conclusion, this study provides compelling evidence of a significant association between exposure to brominated flame retardants (BFRs) and an increased risk of periodontitis in a nationally representative sample of U.S. adults. Elevated serum levels of several BFRs, including PBDE-28, PBDE-47, PBDE-85, PBDE-99, PBDE-100, PBDE-154, PBDE-183, and PBB-153, were found to be positively associated with periodontitis, exhibiting a dose-response relationship.

Brominated Flame Retardants (BFRs) in China Over the Past Half-Century: Stocks, Flows, Fates, and Ecological Risks.

China is a significant producer and consumer of various brominated flame retardants (BFRs), raising environmental concerns due to their widespread presence and potential threats to ecosystems and organisms. This study adopts a life cycle perspective, combining material flow analysis, multimedia environmental modeling, and ecological risk assessment to systematically analyze the substance metabolism and ecological risks of six BFR types in China from 1970 to 2021. The findings reveal that China's cumulative BFR consumption reached 3.3 Mt, with the electronics sector being the predominant contributor at 52.1%. Consequently, 1.5 kt of BFRs were released into the environment, with 24.9%, 31.5%, and 43.6% being discharged into the air, water, and soil, respectively. Notably, the proportion of novel BFRs in emissions has steadily increased over the years, exemplified by the increase in decabromodiphenyl ethane (DBDPE) from 21.3% in 2010 to 30.1% in 2021. Geographically, BFR concentrations are higher in the eastern and southwestern regions compared to those in the northwest. Presently, certain BFRs like tetrabromobisphenol A (TBBPA) and DBDPE exhibit moderate to high ecological risks, primarily concentrated in the Shandong and Sichuan provinces. A combination of efficient recycling, emission control, and substitution with novel flame-retardant can minimize the exposure of BFRs to the environment and organisms.

The impact of brominated flame retardants (BFRs) on pulmonary function in US adults: a cross-sectional study based on NHANES (2007–2012)

Brominated flame retardants (BFRs) are a group of chemicals widely used in various applications to prevent or slow down the spread of fire. However, they have adverse effects on human health. There is a relative scarcity of population-based studies regarding BFRs, particularly their impact on the respiratory system. This study aimed to investigate the influence of BFRs on pulmonary function using data from the National Health and Nutrition Examination Survey. The study found that elevated serum concentrations of certain BFRs were associated with pulmonary ventilatory dysfunction. Adjusted analyses revealed positive correlations between PBDE47, PBDE183, and PBDE209 concentrations and ventilatory dysfunction. The analysis of mixed BFRs showed a positive relationship with pulmonary ventilation dysfunction, with PBDE47 making the most significant contribution. Our study demonstrates that both individual and combined BFRs exposure can lead to impaired pulmonary ventilation function. These findings provide evidence of the adverse effects of BFRs on lung function, emphasizing the importance of further investigating the potential health consequences of these compounds. Further large-scale longitudinal studies are needed to investigate this relationship in the future.

Impact of Legislation on Brominated Flame Retardant Concentrations in UK Indoor and Outdoor Environments: Evidence for Declining Indoor Emissions of Some Legacy BFRs.

Concentrations of polybrominated diphenyl ethers, hexabromocyclododecane (HBCDD), and novel brominated flame retardants (NBFRs) were measured in indoor dust, indoor air, and outdoor air in Birmingham, UK. Concentrations of ΣBFRs ranged from 490 to 89,000 ng/g, 46-14,000 pg/m3, and 22-11,000 pg/m3, respectively, in UK indoor dust, indoor air, and outdoor air. BDE-209 and decabromodiphenyl ethane (DBDPE) were the main contributors. The maximum concentration of DBDPE (10,000 pg/m3) in outdoor air is the highest reported anywhere to date. In contrast with previous studies of outdoor air in Birmingham, we observed significant correlations between concentrations of tri- to hepta-BDEs and HBCDD and temperature. This may suggest that primary emissions from ongoing use of these BFRs have diminished and that secondary emissions (e.g., evaporation from soil) are now a potentially major source of these BFRs in outdoor air. Conversely, the lack of significant correlations between temperature and concentrations of BDE-209 and DBDPE may indicate that ongoing primary emissions from indoor sources remain important for these BFRs. Further research to clarify the relative importance of primary and secondary sources of BFRs to outdoor air is required. Comparison with earlier studies in Birmingham reveals significant (p < 0.05) declines in concentrations of legacy BFRs, but significant increases for NBFRs over the past decade. While there appear minimal health burdens from BFR exposure for UK adults, dust ingestion of BDE-209 may pose a significant risk for UK toddlers.

Risk of Brominated Flame Retardants for Aquatic Organisms

Nowadays, many experiments have detected the residues of halogenated flame retardants in organisms and even human bodies, among which the amount and type of brominated flame retardants (BFRs) are the most. Therefore, research on biological toxicity and possible harms of BFRs need to be studied to adjust the use and disposal of these chemicals to prevent irreversible consequences on the human body. This article mainly introduced the harm of BFRs to aquatic organisms and the solutions to reduce the concentration of BFRs in water. The harm of BFRs to aquatic organisms is mainly reflected in reproductive toxicity and thyroid hormone toxicity. BFRs, as toxic substances, are bio enriched and can enter the human body along the food chain, causing hormonal disorders and other problems. There are three main ways to reduce the concentration of BFRs in the environment including by using simple and easily degradable BFRs at the source, adjusting the light source conditions to enhance the photochemical degradation rate, and developing new adsorption materials.

Neural network for evaluation of the impact of the UK COVID-19 national lockdown on atmospheric concentrations of PAHs and PBDEs

The impact of measures to restrict population mobility during the COVID-19 pandemic on atmospheric concentrations of polycyclic aromatic hydrocarbons (PAH) and brominated flame retardants (BFRs) is poorly understood. This study analyses the effects of meteorological parameters and mobility restrictions during the COVID-19 pandemic on concentrations of PAH and BFRs at the University of Birmingham in the UK utilising a neural network (self-organising maps, SOM). Air sampling was performed using Polyurethane Foam (PUF) disk passive samplers between October 2019 and January 2021. Data on concentrations of PAH and BFRs were analysed using SOM and Spearman's rank correlation. Data on meteorological parameters (air temperature, wind, and relative humidity) and mobility restrictions during the pandemic were included in the analysis. Decabromodiphenyl ether (BDE-209) was the most abundant polybrominated diphenyl ether (PBDE) (23–91% Σ7PBDEs) but was detected at lower absolute concentrations (4.2–35.0 pg m−3) than in previous investigations in Birmingham. Air samples were clustered in five groups based on SOM analysis and the effects of meteorology and pandemic-related restrictions on population mobility could be visualised. Concentrations of most PAH decreased during the early stages of the pandemic when mobility was most restricted. SOM analysis also helped to identify the important influence of wind speed on contaminant concentrations, contributing to reduce the concentration of all analysed pollutants. In contrast, concentrations of most PBDEs remained similar or increased during the first COVID-19 lockdown which was attributed to their primarily indoor sources that were either unaffected or increased during lockdown.

Analysis and Pollution Assessment of Brominated Flame Retardants (PBDEs, DBDPE, and BTPBE) in Settled Dust from E-waste and Vehicle Processing Areas in Northern Vietnam

Polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) are typical brominated flame retardants (BFRs), which were widely added to polymeric and textile materials to meet fire safety requirements. PBDEs (including commercial penta-, octa-, and deca-BDE mixtures) have been classified as persistent organic pollutants (POPs) under the Stockholm Convention, while DBDPE and BTBPE are considered as PBDE replacements. In the present study, concentrations of PBDEs (major congeners of technical PBDE mixtures such as BDE-28, 47, 99, 100, 153, 154, 183, 197, 207, and 209), DBDPE, and BTBPE were simultaneously analyzed in settled dust samples collected from e-waste and end-of-life vehicle (ELV) processing areas in northern Vietnam. The dust samples were extracted by using an ultrasonic processor subsequently by acetone and acetone/hexane (1:1) mixture for 10 min each time. The dust extract was treated with concentrated sulfuric acid and activated silica gel to remove interferences. BFRs were analyzed by using gas chromatography/mass spectrometry (GC/MS) equipped with a DB-5ht column. The mass spectrometer was operated at electron capture negative ionization (ECNI) and selected ion monitoring (SIM) mode. Concentrations of total PBDEs, DBDPE, and BTBPE ranged from 77 to 240,000 (median 6000), from &lt;20 to 240,000 (median 5500), and from &lt;10 to 9200 (median 160) ng/g, respectively. Concentrations of BFRs in the e-waste dust were significantly higher than those measured in the ELV dust, suggesting e-waste processing activities as potential sources of BFRs in dust. Among BFRs analyzed, BDE-209 and DBDPE were the most predominant compounds, implying intensive application of deca-BDE mixtures and alternative formulations.

Factors affecting the levels and pathways of atmospheric brominated flame retardant uptake by humans in different weather conditions

The health risks posed by atmospheric brominated flame retardants (BFRs) have been widely studied, but there remains a lack of clarity about exposure differences between clear days and haze days. We sampled the total suspended particle (TSP) and gaseous BFRs on clear days in summer, clear days in winter, and haze days in winter in Harbin, China, to investigate the variations in the concentrations and intakes (dermal and inhalation) in the different weather conditions. The concentrations of atmospheric BFRs were highest on haze days in winter (185 pg/m3), followed by clear days in summer (158 pg/m3), and clear days in winter (79.2 pg/m3), and these concentrations were significantly correlated with the concentrations of TSP. The human intake in the different weather conditions followed the pattern of the BFR concentrations, and the human intake of atmospheric BFRs was dominated by inhalation. A comparison of the BFR levels showed that the human intake of gaseous and particulate BFRs varied in the three weather conditions and that the inhalation intake, but not the dermal intake, was influenced under high concentrations of gaseous BFRs with low molecular weight.

Temporal trends in concentrations of brominated flame retardants in UK foodstuffs suggest active impacts of global phase-out of PBDEs and HBCDD

Global restrictions on use of legacy brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCDD) have generated demand for novel BFRs (NBFRs) as substitutes. Our research group has previously reported decreased concentrations of PBDEs and HBCDD and increased concentrations of NBFRs in UK indoor environments, suggesting that restrictions on PBDEs and HBCDD are exerting an impact. In this study, we analysed UK foodstuffs collected in 2020–21 and compared the BFR concentrations found with those found in similar samples collected in 2015 to investigate whether similar trends in BFR concentrations would be observed. Concentrations of PBDEs and HBCDD isomers detected in our samples had declined by 78–92 % and 59–97 % since the 2015 study, respectively. Moreover, concentrations of NBFRs (dominated by 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE or TBE), and bis(2-ethyl hexyl) tetrabromophthalate (BEH-TEBP or TBPH)) in UK foodstuffs increased significantly (28–1400 %) between 2015 and 2020–21. Combined, these findings suggest that restrictions on use of PBDEs and HBCDD have had a discernible impact on concentrations of these legacy BFRs and their NBFR replacements in UK foodstuffs. Interestingly, given recent reports of a significant increase in concentrations of decabromodiphenyl ethane (DBDPE) in UK house dust between 2014 and 2019, a significant decline (70–84 %) in concentrations of DBDPE was observed in UK foodstuffs.

Sediment contamination with polybrominated diphenyl ethers and alternative brominated flame retardants: case study in urban lakes of Hanoi,Vietnam.

Information regarding the contamination of brominated flame retardants (BFRs) in lake sediments from Vietnam and Southeast Asia is still very limited. To fill such knowledge gaps, surface sediment samples from five urban lakes in Hanoi, Vietnam, were analyzed for polybrominated diphenyl ethers (PBDEs) and some other BFRs. Concentrations of total PBDEs ranged from 1.1 to 26 (median 6.6) ng/g dry weight with the most predominant congeners as BDE-209 (62 ± 17%), BDE-99 (10 ± 8%), and BDE-47 (6 ± 5%). Concentrations of other BFRs decreased in the order: decabromodiphenyl ethane (DBDPE) > 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) > hexabromobiphenyl (BB-153) > pentabromoethylbenzene (PBEB), which were about one to two orders of magnitude lower than PBDEs. BDE-209 and DBDPE were highly correlated (Pearson's r = 0.879; p < 0.01), suggesting their similar applications and/or environmental fate. Potential sources of BFRs in lake sediments are estimated to be wastewater discharge, riverine inflow, and atmospheric deposition.

Brominated flame retardants (PBDEs and HBCDs) and perfluoroalkyl substances (PFASs) in wild boars (Sus scrofa) from Central Italy

Twenty-six samples of wild boar liver and muscle from the Central Apennine Mountain (Italy) were analysed for 19 perfluoro-alkyl substances (PFASs), 10 polybrominated diphenylethers (PBDEs) and 3 hexabromocyclododecanes (HBCDs). All samples were analysed by gas chromatography–tandem mass spectrometry for PBDEs and liquid chromatography–tandem mass spectrometry for PFASs and HBCDs, using an in-house developed analytical procedure. The brominated flame retardants (BFR) levels in livers were negligible: Σ10PBDEs reached a maximum value of 0.079 μg/kg, whereas HBCDs were not quantified in almost all of the samples analysed. BFR concentrations in muscles were higher, but not significantly therefore, for Σ10PBDEs lower bound, a mean value of 0.045 μg/kg (0.005–0.155 μg/kg range) was measured, while α-HBCD was quantified with a maximum of 0.084 μg/kg in 9 of the samples. Only two muscles contained all 3 HBCD isomers at concentrations of approximately 0.200 μg/kg. Σ19PFAS in the 26 wild boar livers was in the range 31.9–228 μg/kg, with a mean value of 87.7 μg/kg, reaching levels significantly higher than in muscles, which exhibited a mean concentration of 3.08 μg/kg (0.59–9.12 μg/kg range). Perfluorooctanesulfonic acid (PFOS) was the most prevalent compound in all liver samples, accounting for more than half of the total PFASs contamination, confirming that the liver is the primary target organ for PFOS exposure Perfluorotridecanoic acid (PFTrDA), which accounts for 25–30-% of the total contamination, was the most abundant compound in the muscle, followed by PFOS.The estimated daily intake (EDIs) of BFRs remained below the estimated chronic human daily dietary intake (Dr,h) defined from European Food Safety Authority (EFSA). Furthermore, the exposure to PFASs in muscle was 7.7 times lower than the EFSA's tolerable daily intake (TDI).In contrast, exposure due to liver consumption was significant: the EDI exceeded the EFSA's 2020 TDI by approximately 7 times.

Distribution of flame retardants among indoor dust, airborne particles and vapour phase from Beijing: spatial–temporal variation and human exposure characteristics

The occurrence and distribution of 10 brominated flame retardants (BFRs) and 10 organophosphate flame retardants (OPFRs) were investigated in indoor dust, total suspended particles (TSP), and vapour phase from offices (n = 10), homes (n = 9), and day-care centres (n = 10) in Beijing, China. Three types of samples were collected biweekly from one office and one home over a year to examine temporal trends. BFRs in dust significantly correlated with those in TSP, while OPFRs significantly correlated among all three matrices. In addition, BFRs in dust (ng/g) and TSP (pg/m3) exhibited similar temporal trends with higher levels in the cold season, whereas OPFRs in TSP and vapour phase (pg/m3) showed similar temporal trends with higher levels in the warm season. The geometric mean concentrations of BFRs and OPFRs in the three matrices from the above mentioned three types of indoor microenvironments were used for exposure and health risk estimation, and ∑7OPFRs showed much higher hazard index (HI) values than ∑10BFRs for all subpopulations, and inhalation of OPFRs was a major risk source. With the volatility of flame retardants (FRs) decreasing, the contribution of dust ingestion and dermal absorption showed an increasing trend, and the contribution of inhalation exhibited a gradual decreasing trend, which implied the dominant exposure pathway to FRs is strongly related to the vapour pressure (25 °C, Pa) of these substances. Using a single type of microenvironment or the collection of samples at a single point in time can lead to overestimation or underestimation of overall exposure and risk for people to some extent. The correlations of FRs in dust, TSP, and vapour phase from indoor microenvironments, as well as their temporal trends were first reported in this study, which will provide a basis for more accurate FR exposure assessments in the future.

Distribution characteristics and risks assessment of brominated flame retardants in surface soil from both a legacy and a new e-waste dismantling site

Brominated flame retardants (BFRs) are widely used in diverse industries, resulting in extensive environmental contamination. Although many legacy BFRs have been banned and replaced with novel brominated flame retardants (NBFRs), these NBFRs have also been found to exhibit toxicity and persistence. In this study, 55 soil samples were collected from areas surrounding an abandoned (FJ) and a newly built (TZ) e-waste dismantling zone which represent the traditional and modern e-waste dismantling practice in China, respectively, to examine and compare the occurrence of BFRs and their potential ecological and health risks. The concentrations of novel brominated flame retardants (NBFRs) ranged from 10.0 to 2,390 ng/g dw, and those of polybrominated diphenyl ethers (PBDEs) ranged from 78.0 to 13,300 ng/g dw. Decabromodiphenyl ethane (DBDPE) to BDE-209 ratios were greater than one in 6.8% and 25% of samples in FJ and TZ, respectively. BFRs concentrations in FJ soils significantly decreased with increasing distance to the center of FJ, indicating that the soil in the FJ region was strongly affected by the e-waste dismantling activities in FJ. For TZ, only DBDPE exhibited similar regulation, indicating that the newly built e-waste dismantling zone has already impacted on the surrounding environment. The Mann–Whitney test showed that the concentrations of most PBDE congeners were higher in FJ (P < 0.01/0.05) than those in TZ, while there was no significant difference in the concentrations of most NBFRs between FJ and TZ. A low abundance of BDE-209 in soils suggests that its degradation process and DBDPE was the predominant NBFRs in soils from both FJ and TZ. It was found that low-brominated PBDE congeners posed high ecological risks to terrestrial animals, which the ecological risks may increase in the future due to the debromination process of high PBDE congeners. The health hazard of BFRs via soil exposure in FJ was generally higher than in TZ, although both were acceptable. Despite much greater average daily doses for BDE-209 and DBDPE, the oral hazard quotients of BDE-47 and BDE-99 were much higher. Toddlers were found to face a higher health risk due to soil exposure than teenagers and children. The carcinogenic effect of BDE-209 was also acceptable in FJ and TZ. With the continuous operation of the TZ site, the further accumulation of BFRs in soils and health hazard via BFRs exposure are expected, and the results suggest that ongoing monitoring and further research is necessary. We believe that our work could help researchers investigate and reveal the harmful impacts of NBFRs and PBDEs.

Occurrence, emission sources, and risk assessment of polybrominated diphenyl ethers and current-use brominated flame retardants in settled dust from end-of-life vehicle processing, urban, and rural areas, northern Vietnam.

Settled dust samples from Vietnamese end-of-life vehicle (ELV) processing, urban, and rural areas were analyzed for polybrominated diphenyl ethers (PBDEs) and other current-use brominated flame retardants (BFRs). PBDE levels found in dust samples collected from ELV workshops (median 390; range 120-520ng/g) and nearby living areas (110; 36-650ng/g) were generally higher than those in common house dust (25-170ng/g). BDE-209 was the most predominant congener detected in almost all the samples, indicating extensive application of products containing deca-BDE mixtures. The dust samples from ELV workplaces showed a more abundance of lower brominated congeners (e.g., tetra- to hexa-BDEs) that may originate from car interior materials treated by penta-BDE formulations. Concentrations of other BFRs decreased in the order urban > rural > ELV dust, reflecting the current use of these compounds in new consumer products. Decabromodiphenyl ethane (DBDPE) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were the major alternative BFRs. Daily intake doses and hazard indexes of PBDEs and some other BFRs through dust ingestion were estimated and showed acceptable levels of risk. However, more comprehensive risk assessment considering multiple exposure pathways should be performed, especially for ELV workers and children in the ELV processing and urban areas.

Atmospheric concentrations of polychlorinated biphenyls, brominated flame retardants, and novel flame retardants in Lagos, Nigeria indicate substantial local sources.

Polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs) like polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCDD), and novel flame retardants (NFRs) like decabromodiphenyl ethane (DBDPE) are ubiquitous environmental pollutants. Despite this, little is known about their concentrations in outdoor air in the African continent. To address this knowledge gap, concentrations of BFRs, NFRs, and PCBs were measured in outdoor air at 8 sites located within the metropolitan area of Lagos, Nigeria. Concentrations of ∑8BDEs, ∑HBCDD, ∑7NFRs and ∑8PCBs were: 21-750 (median=100) pg/m3, <12-180 (median =<12) pg/m3, 34-900 (median=300) pg/m3 and 85-460 (median=300) pg/m3, respectively. Decabromodiphenyl ether (BDE-209, range: <16-620pg/m3, median=71pg/m3) and DBDPE (range: <37-890pg/m3, median=280pg/m3) were the dominant BFRs detected, while the non-Arochlor PCB 11 (range: 49-220pg/m3, median=100pg/m3) was the dominant PCB. To the authors' knowledge, these are the first data on the non-Arochlor PCB 11 in outdoor air in Africa. In general, concentrations of all target contaminants in this study were within the range reported elsewhere in Africa and worldwide. Likely due to the tropical climate of Lagos, no seasonal variation in concentrations was discernible for any of the target contaminants. While concentrations of PBDEs and some NFRs were correlated with population density, concentrations of PCBs appear more impacted by leaks from electrical transformers and for PCB 11 to proximity to activities like textile factories that produce and use dyes.

Contamination status, emission sources, and human health risk of brominated flame retardants in urban indoor dust from Hanoi, Vietnam: the replacement of legacy polybrominated diphenyl ether mixtures by alternative formulations.

This study investigated the occurrence, distribution of several additive brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and some novel brominated flame retardants (NBFRs) in urban indoor dust collected from ten inner districts of Hanoi, Vietnam to assess the contamination status, emission sources, as well as their associated human exposure through indoor dust ingestion and health risks. Total concentrations of PBDEs and NBFRs in indoor dust samples ranged from 43 to 480 ng g-1 (median 170 ng g-1) and from 56 to 2200 ng g-1 (median 180 ng g-1), respectively. The most abundant PBDE congener in these dust samples was BDE-209 with concentrations ranging from 29 to 360 ng g-1, accounting for 62.6-86.5% of total PBDE levels. Among the NBFRs analyzed, decabromodiphenyl ethane (DBDPE) was the predominant compound with a mean contribution of 98.6% total NBFR amounts. Significant concentrations of DBDPE were detected in all dust samples (median 180 ng g-1, range 54-2200 ng g-1), due to DBDPE as a substitute for deca-BDE. Other NBFRs such as 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), pentabromoethylbenzene (PBEB) and 2,2',4,4',5,5'-hexabromobiphenyl (BB-153) were found at very low levels. Based on the measured BFR concentrations, daily intake doses (IDs) of PBDEs and NBFRs via dust ingestion at exposure scenarios using the median and 95th percentile levels for both adults and children were calculated for risk assessment. The results showed that the daily exposure doses via dust ingestion of all compounds, even in the high-exposure scenarios were also lower than their reference dose (RfD) values. The lifetime cancer risks (LTCR) were much lower than the threshold level (10-6), which indicated the acceptable health risks resulting from indoor BFRs exposure for urban residents in Hanoi.

Spatio-temporal variations and input patterns on the legacy and novel brominated flame retardants (BFRs) in coastal rivers of North China

Decabromodiphenyl ether (BDE209) has been subject to restrictions since 2018 in developed countries but is still manufacturing in China. Decabromodiphenyl ethane (DBDPE) is widely used as a replacement for BDE209. To better understand the behaviors and fates of these legacy and novel brominated flame retardants (BFRs), water samples were collected from the estuaries of 36 rivers that drain into the Bohai Sea (BS) and North Yellow Sea (NYS) in 2017 and 2018. The results showed that BDE209 was still the predominant compound with a median concentration of 2470 pg L−1, whereas DBDPE had a median concentration of 129 pg L−1. Spatially, relatively high concentrations were observed in the rivers near Laizhou Bay (LB), which is the manufacturing hub of BFRs. BDE209 concentrations were significantly higher in dry season than in wet season, which indicates a dominant process of dilution by precipitation during the wet season. DBDPE concentration showed no significant seasonal difference. This implies that wet deposition was the major additional source of DBDPE during the wet season, and the concentration increased further during the autumn as a result of a time-lag effect. The BFR concentrations in urban rivers were lower than those reported by a study undertaken in August 2013. An increase in the BFR concentrations in rural rivers since 2013 suggested increases in the use and non-point source emissions of BFRs in some remote aquatic environments. The estimated annual inputs of BDE209 and DBDPE into the BS were ∼95.9 kg yr−1 and ∼26.8 kg yr−1, respectively, whereas those into the NYS were ∼24.1 kg yr−1 and ∼8.38 kg yr−1. The results revealed an ecological risk of BDE209 in winter especially in the Xiaoqing River, thus suggesting the impact of BDE209 on the aquatic environment and human health.

Seasonal rainfall affects occurrence of organohalogen contaminants in tropical marine fishes and prawns from Zanzibar, Tanzania

Seasonal differences in precipitation may affect contaminant dynamics in tropical coastal regions due to terrestrial runoff of contaminants to the marine environment after the rainy seasons. To assess the effect of seasonal rainfall on occurrence of organohalogen contaminants in a coastal ecosystem, marine fishes and prawns were collected off the coast of Zanzibar, Tanzania in January and August 2018, representing pre- and post-rainy season, respectively. Samples were analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs) and emerging BFRs, as well as the dietary descriptors stable isotopes of carbon (δ13C) and nitrogen (δ15N). Across all species and seasons, mean contaminant concentrations ranged from below limit of detection (LOD) to 129 ng/g lipid weight (lw) ΣPCBs; 5.6–336 ng/g lw ΣOCPs; and < LOD –22.1 ng/g lw ΣPBDEs. Most of the emerging BFRs were below LOD. Contaminant concentrations generally increased with higher pelagic carbon signal (δ13C) and higher relative trophic position (δ15N). The ratio of DDE/ΣDDTs in fishes and prawns was lower in August than in January, suggesting runoff of non-degraded DDT into the marine system during or after the seasonal rainfall. Contaminant patterns of OCPs and PCBs, and concentrations of BFRs, differed between seasons in all species. A higher relative concentration-increase in lower halogenated, more mobile PCB and PBDE congeners, compared to higher halogenated congeners with lower mobility, between January and August aligns with a signal and effect of terrestrial runoff following the rainy season.

Assessment of polybrominated diphenyl ethers and emerging brominated flame retardants in Pheretima (a Traditional Chinese Medicine): Occurrence, residue profiles, and potential health risks.

China produces and consumes large quantities of brominated flame retardants (BFRs) as well as several other unregulated electronic waste recycling activities, causing high BFR concentrations in the natural environment. Thus, Traditional Chinese Medicines (TCMs) may be contaminated by legacy BFRs (e.g. polybrominated diphenyl ethers (PBDEs)) and emerging BFRs (eBFRs, such as decabromodiphenyl ethane (DBDPE)) during growth, processing, packaging, and transportation. Pheretima, which is a typical animal drug recorded in Chinese Pharmacopoeia, was used as an example to evaluate human exposure to BFRs through TCM intake. This study is the first to determine 25 PBDEs and 5 eBFRs in Pheretima and estimate the daily BFR intake via Pheretima-containing TCMs. Twenty-seven Shanghai Pheretima and fifty-one Guang Pheretima samples were collected between March and June 2019 in southeast China. High BFR detection frequencies were found in Pheretima, of which BDE-209 and DBDPE were the most predominant analytes. The total PBDE contents ranged from 73pg/g to 8,725pg/g, while that of the eBFRs varied between 115pg/g and 2,824pg/g. The profiles and abundances were found to be species- and origin-dependent. However, the traditional processing of Pheretima may reduce BFR residues. Based on the usual clinical doses of Pheretima and the available chronic oral reference doses of BDE-47, 99, 153, and 209, the mean (95th percentile) of the total hazard quotient was estimated to be 9.1×10-5 (2.7×10-4). Therefore, there is little risk related to BFR exposure for patients taking formulated Pheretima-containing TCMs. However, it is necessary to establish routine monitoring programs for the co-existence of pollutants in TCMs to perform a systematic and comprehensive risk assessment.

Brominated flame retardants (BFRs) in PM2.5 associated with various source sectors in southern China.

The present study investigates legacy and novel brominated flame retardants (BFRs) in atmospheric PM2.5 associated with various urban source sectors in a city and electronic waste (e-waste) recycling facilities in southern China. The concentrations of polybrominated diphenyl ethers (PBDEs) and novel BFRs (∑2NBFRs) at the urban industrial park (UIP) sites varied greatly from 22.0 to 105 pg m-3 and from to 29.7 to 459 pg m-3, respectively, and higher concentrations were generally found at sites involving industrial sectors of electronics, plastics, and machinery. Their spatial variations at other urban potential source sites were small suggesting a lack of strong point emissions. The levels of PBDEs and ∑2NBFRs at the e-waste facilities (220-2356 pg m-3 and 83.6-569 pg m-3) were significantly higher and did not temporally decline, indicating that improvement in e-waste recycling techniques does not significantly reduce emissions of PBDEs. NBFRs dominated the BFRs at the urban sites (55% on average), while PBDEs were still dominant (78%) at the e-waste sites. PBDE congener profiles in PM2.5 were substantially different from those in commercial mixtures. The congener profiles as well as their correlations suggested frequent formation of lower brominated PBDEs from degradation of highly brominated congeners in this region, which became appreciable due to the reduced emissions. The significant correlations among the lower brominated congeners also reflected similar environmental behaviors due to similar physicochemical properties.