RESUMEN
Hexabromocyclododecanes (HBCDs) are legacy additive brominated flame retardant. In present study, the distribution, biomagnification and potential human health risk associated with HBCDs were investigated in six edible marine fish species collected from three bays in the Beibu Gulf, China, between March and October 2021. The concentration of HBCDs ranged from 0.05 to 200 ng/g lipid weight (lw), with Scoliodon laticaudus and Trichiurus nanhaiensis having the highest and lowest concentration, respectively. The α-HBCD was dominant in most studied fish, expect for Scoliodon laticaudus. Dietary source was the primary factor for the diastereomeric profiles of HBCDs in fish. Only γ-HBCD demonstrated trophic magnification in the studied fish species. Finally, the estimated daily intake (EDI) was 0.18 ng/kg/day for adults, 0.17 ng/kg/day for teenager and children, and all corresponding margin of exposure (MOE) values were lager than 8 indicating relatively low human exposure risks from fish consumption.
Asunto(s)
Peces , Hidrocarburos Bromados , Alimentos Marinos , Contaminantes Químicos del Agua , Animales , Hidrocarburos Bromados/análisis , China , Contaminantes Químicos del Agua/análisis , Humanos , Exposición Dietética , Retardadores de Llama , Contaminación de Alimentos/análisis , Monitoreo del Ambiente , Medición de RiesgoRESUMEN
Sediment is the ultimate sink of environmental pollutants. A total of 128 surface sediment samples were collected from 8 rivers and 3 reservoirs in Maoming City, Guangdong Province. This study assessed the content and distribution of brominated flame retardants in sediments. The acute toxicity effects of tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDs) in sediments were evaluated using Caenorhabditis elegans as model organisms. The concentration of TBBPA in sediments ranged from not detected (ND) to 12.59 µg/kg and was mainly distributed in the central area, which was affected by the emission of TBBPA from residential and factory. The concentration of HBCDs ranged from ND to 6.31 µg/kg, and the diastereoisomer distribution was consistent, showing a trend close to the South China Sea. The composition pattern of HBCDs in the surface sediments from rivers were 41.73%-62.33%, 7.89%-25.54%, and 18.76%-40.65% for α-, ß-, and γ-HBCD, respectively, and in the sediments from reservoirs were 26.15%-45.52%, 7.44%-19.23%, and 47.04%-61.89% for α-, ß-, and γ-HBCD, respectively. When the sum of concentrations of TBBPA and HBCD in sediments were above high levels, reactive oxygen species in nematodes significantly increased, resulting in an oxidative stress response. Intestinal permeability was also enhanced, causing intestinal damage. In addition, in terms of this study, TBBPA had a greater impact on biotoxicity compared to HBCDs, and more attention should be paid to the toxic effects of the river ecosystem organisms in Maoming City, Guangdong Province. This study can complement the pollution database in the study area and provide basic data for pollution control.
Asunto(s)
Caenorhabditis elegans , Monitoreo del Ambiente , Retardadores de Llama , Sedimentos Geológicos , Hidrocarburos Bromados , Contaminantes Químicos del Agua , Animales , Retardadores de Llama/toxicidad , Retardadores de Llama/análisis , China , Caenorhabditis elegans/efectos de los fármacos , Sedimentos Geológicos/química , Contaminantes Químicos del Agua/toxicidad , Contaminantes Químicos del Agua/análisis , Hidrocarburos Bromados/análisis , Hidrocarburos Bromados/toxicidad , Bifenilos Polibrominados/toxicidad , Bifenilos Polibrominados/análisisRESUMEN
Brominated flame retardants (BFRs) exhibit excellent flame retardant properties and are widely used in various industries. Among the common BFRs, tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDs) pose substantial ecological and human health risks due to their extensive application and long-range transport. This study established 131 sample collection sites along the coast of the South China Sea (SCS) in Guangdong Province to assess the concentration, distribution, inventory, and ecological risk of TBBPA and HBCDs in surface sediments. The concentrations of TBBPA in SCS sediments ranged from < limit of detection (LOD) to 80 µg/kg dry weight (dw), and those of HBCDs from < LOD to 18 µg/kg dw. The diastereoisomers of HBCDs (α-, ß-, and γ-HBCD) in the sediment samples accounted for 36 %, 13 %, and 51 %, respectively. Human activities, particularly those associated with nearby electronic waste disassembly and textile and garment industries, considerably influenced the dispersion of TBBPA and HBCDs. The inventories of TBBPA and HBCDs in Guangdong Province's SCS were estimated to be 3.2 × 105 kg and 7.2 × 104 kg, respectively. The average risk quotient values ranged from <0.01 to 0.016, indicating a low to negligible environmental risk. This study provides deeper insights into the distribution and scientific significance of HBCDs and TBBPA in SCS sediment samples, elucidates the current state of BFR contamination, and offers recommendations for future research on environmental safety and human health in the region.
Asunto(s)
Monitoreo del Ambiente , Retardadores de Llama , Sedimentos Geológicos , Hidrocarburos Bromados , Bifenilos Polibrominados , Contaminantes Químicos del Agua , Bifenilos Polibrominados/análisis , Hidrocarburos Bromados/análisis , China , Sedimentos Geológicos/química , Medición de Riesgo , Monitoreo del Ambiente/métodos , Retardadores de Llama/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Novel brominated flame retardants (NBFRs) have been developed as replacements for legacy brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). The prevalence of NBFRs in aquatic environments has initiated intense concerns that they resemble to BFRs. To comprehensively elucidate the fate of NBFRs in aquatic environments, this review summarizes the physico-chemical properties, distribution, bioaccumulation, and fates in aquatic environments. 1,2-bis(2,3,4,5,6-pentabromophenyl) ethane (DBDPE) as the major substitute for PBDEs is the primary NBFR. The release from industrial point sources such as e-waste recycling stations is the dominant way for NBFRs to enter the environment, which results in significant differences in the regional distribution of NBFRs. Sediment is the major sink of NBFRs attributed to the high hydrophobicity. Significantly, there is no decreasing trend of NBFRs concentrations, while PBDEs achieved the peak value in 1970-2000 and decreased gradually. The bioaccumulation of NBFRs is reported in both field studies and laboratory studies, which is regulated by the active area, lipid contents, trophic level of aquatic organisms, and the log KOW of NBFRs. The biotransformation of NBFRs showed similar metabolism patterns to that of BFRs, including debromination, hydroxylation, methoxylation, hydrolysis, and glycosylation. In addition, NBFRs show great potential in trophic magnification along the aquatic food chain, which could pose a higher risk to high trophic-level species. The passive uptake by roots dominates the plant uptake of NBFRs, followed by acropetal and basipetal bidirectional transportation between roots and leaves in plants. This review will provide the support to understand the current pollution characteristics of NBFRs and highlight perspectives for future research.
Asunto(s)
Monitoreo del Ambiente , Retardadores de Llama , Éteres Difenilos Halogenados , Hidrocarburos Bromados , Contaminantes Químicos del Agua , Retardadores de Llama/metabolismo , Retardadores de Llama/análisis , Contaminantes Químicos del Agua/análisis , Contaminantes Químicos del Agua/metabolismo , Éteres Difenilos Halogenados/metabolismo , Éteres Difenilos Halogenados/análisis , Hidrocarburos Bromados/metabolismo , Hidrocarburos Bromados/análisis , BioacumulaciónRESUMEN
Brominated flame retardants (BFRs) are bromine-bearing additives added to the polymeric fraction in various applications to impede fire ignition. The Stockholm Convention and various other legislations abolished legacy BFRs usage and hence, the so-called novel BFRs (NBFRs) were introduced into the market. Recent studies spotlighted their existence in household dust, aquifers and aquatic/aerial species. Co-pyrolysis of BFRs with metal oxides has emerged as a potent chemical recycling approach that produces a bromine-free stream of hydrocarbon. Herein, we investigate the debromination of two prominent two NBFRs; namely tetrabromobisphenol A 2,3-dibromopropyl ether (TD) and tetrabromobisphenol A diallyl ether (TAE) through their co-pyrolysis with zinc oxide (ZnO) and franklinite (ZnFe2O4). Most of the zinc content in electrical arc furnace dust (EAFD) exists in the form of these two metal oxides. Conversion of these metal oxides into their respective bromides could also assist in the selective extraction of the valuable zinc content in EAFD. The debromination potential of both oxides was unveiled via a multitude of characterization studies to analyze products (char, gas and condensates). The thermogravimetric analysis suggested a pyrolytic run up to 500 °C and the TAE treatment with ZnO produced only a trivial amount of brominated compounds (relative area, 0.83%). Phenol was the sole common compound in condensable products; potentially formed by the ß-scission debromination reaction from the parental molecular skeleton. Inorganic compounds and methane were the major constituents in the gaseous products. The pyrochar analyses confirmed the presence of metal bromides retained in the residue, averting the bromine release into the atmosphere. The ion chromatography analysis portrayed <8% of HBr gas release into the atmosphere upon pyrolysis with ZnO. The ZnO dominance herein envisaged further probes into other spinel ferrites in combating brominated polymers.
Asunto(s)
Residuos Electrónicos , Retardadores de Llama , Hidrocarburos Bromados , Bifenilos Polibrominados , Óxido de Zinc , Retardadores de Llama/análisis , Residuos Electrónicos/análisis , Bromo , Bromuros , Reciclaje/métodos , Polímeros , Zinc/análisis , Polvo , Éteres , Hidrocarburos Bromados/análisisRESUMEN
Persistent pollutants, namely brominated flame retardants (BFRs) and heavy metals, are compounds that are added to a wide range of products and materials for preventing ignition, increasing the functionality of materials or improving their performance, e.g. electric conductivity. The exposure of children might consequently be inferred, through indoor dust and hand-to-mouth or toy-chewing behaviors. The current study is aimed at assessing the exposure of Moroccan children to BFRs and heavy metal elements, and evaluating their associations with global DNA methylation. First, parents responded to a questionnaire pertaining to children's lifestyle, then blood and urine samples were collected from (n = 93) children aged between 5 and 11 years for biomonitoring and DNA methylation analysis. BFRs were detected in 54.84% of samples with a median concentration of 0.01 nmol/mL (range: 0.004-0.051 nmol/mL) while metal elements were detected in more than 90% of samples. BFRs showed no variations with global DNA methylation, unlike metal elements, which revealed significant associations with global DNA methylation markers, namely 5-mC, 5-hmC and N6-mA levels. Moroccan children may be exposed to flame retardants and heavy metals through several routes. Further research is required to assess the exposure and the health impacts of environmental pollutants and ultimately protect the Moroccan population by the prevention of adverse health effects.
Asunto(s)
Contaminación del Aire Interior , Contaminantes Ambientales , Retardadores de Llama , Hidrocarburos Bromados , Metales Pesados , Niño , Humanos , Preescolar , Retardadores de Llama/análisis , Marruecos , Contaminación del Aire Interior/análisis , Éteres Difenilos Halogenados/análisis , Contaminantes Ambientales/análisis , Polvo/análisis , Metales Pesados/análisis , Adenina/análisis , Monitoreo del Ambiente , Exposición a Riesgos Ambientales/análisis , Hidrocarburos Bromados/análisisRESUMEN
The brominated flame retardant tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) (TBBPA-DBMPE) is a recommended substitute for hexabromocyclododecane (HBCD), a banned persistent organic pollutant, yet its potential toxicities remains largely unexplored. Here, we investigated the effects of a long-term exposure to TBBPA-DBMPE at nominal doses of 50 and 1000 µg/kg/d on lipid homeostasis in CD-1 mice, in comparison with 50 µg/kg/d HBCD as a positive control. Male pups received chemical treatments through maternal administration via drinking water from postnatal day 0-21, followed by direct administration through drinking water after weaning. On the 23rd week after treatment, the oral lipid tolerance test revealed that low-dose TBBPA-DBMPE as well as HBCD affected lipid tolerance, although the fasting serum triglyceride (TG) levels were not altered. When chemical treatment was extended to the 32nd week, TBBPA-DBMPE-treated animals displayed adipocyte hypertrophy in both white adipose tissue (eWAT) and brown adipose tissue (BAT) and hepatic steatosis, which was largely consistent with the effects of HBCD. These findings indicate that like HBCD, TBBPA-DBMPE led to increased lipid load in mice. Interestingly, we also observed intestinal histological changes, coupled with increased expression of lipid absorption-related genes in both HBCD and TBBPA-DBMPE treatments, suggesting increased lipid absorption. This was supported by in vitro findings that both HBCD and TBBPA-DBMPE promoted lipid accumulation in IEC-6 cells under the stress of oleic acid for 6 h, implying that altered lipid absorption by the intestine may partly contributed to increased lipid load in mice. Overall, the effects of 50 µg/kg/d TBBPA-DBMPE in terms of some parameters were comparable with 50 µg/kg/d HBCD, suggesting that TBBPA-DBMPE may not be an ideal substitute of HBCD.
Asunto(s)
Agua Potable , Retardadores de Llama , Hidrocarburos Bromados , Bifenilos Polibrominados , Masculino , Ratones , Animales , Retardadores de Llama/toxicidad , Retardadores de Llama/análisis , Éter , Hidrocarburos Bromados/toxicidad , Hidrocarburos Bromados/análisis , Bifenilos Polibrominados/toxicidad , Bifenilos Polibrominados/análisis , Éteres , Éteres de Etila , LípidosRESUMEN
Hexabromocyclododecanes (HBCDs) have become a global pollution problem, particularly in China-a major producer and user of HBCDs. However, little is known about the HBCD pollution status in urban rivers nationwide in China. In this study, we comprehensively investigated the pollution characteristics of HBCDs in 173 sediment samples from black-odorous urban rivers across China. Total HBCD concentrations ranged from not-detected to 848 ng/g dw, showing significant differences among the various sampling cities, but generally increasing from west to east China. This distribution pattern of HBCDs was strongly associated with the local industrial output, gross domestic product, and daily wastewater treatment capacity. α-HBCD was the predominant diastereoisomer in most sediments, with an average proportion of 63.8 ± 18.8 %, followed by γ-HBCD (23.8 ± 19.5 %) and ß-HBCD (12.4 ± 6.49 %), showing a significant increase of the α-HBCD proportions relative to those in HBCD commercial mixtures and an opposite trend for that of γ-HBCD. These results suggested that HBCDs might undergo isomerization from γ- to α-HBCD and biotic/abiotic degradation with preference for γ-HBCD. Of these conversions, the microbial degradation of HBCDs was further verified by the preferential transformation of (-)-α-, (+)-ß-, and (-)-γ-HBCDs and the detection of HBCD-degrading bacteria, including Dehalococcoides, Bacillus, Sphingobium, and Pseudomonas. A risk assessment indicated that HBCDs pose low to moderate risks to aquatic organisms in most black-odorous urban river sediments.
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Ríos , Monitoreo del Ambiente/métodos , Sedimentos Geológicos , Hidrocarburos Bromados/análisis , China , Medición de Riesgo , Retardadores de Llama/análisisRESUMEN
Hexabromobenzene (HBB), pentabromotoluene (PBT), and pentabromoethylbenzene (PBEB) are current-use brominated flame retardants (cuBFRs) which have been repeatedly detected in environmental samples. Since information on hydroxylated transformation products (OH-TPs) was scarcely available, the three polybrominated compounds were UV irradiated for 10 min in benzotrifluoride. Fractionation on silica gel enabled the separate collection and identification of OH-TPs. For more insights, aliquots of the separated OH-TPs were UV irradiated for another 50 min (60 min total UV irradiation time). The present investigation of polar UV irradiation products of HBB, PBT, and PBEB was successful in each case. Altogether, eight bromophenols were detected in the case of HBB (three Br3-, four Br4-, and one Br5-isomer), and nine OH-TPs were observed in the case of PBT/PBEB (six Br3- and three Br4-congeners). In either case, BrâOH exchange was more relevant than HâOH exchange. Also, such exchange was most relevant in meta- and ortho-positions. As a further point, and in agreement with other studies, the transformation rate decreased with decreasing degree of bromination. UV irradiation of HBB additionally resulted in the formation of tri- and tetrabrominated dihydroxylated compounds (brominated diphenols) that were subsequently identified. These dihydroxylated transformation products were found to be more stable than OH-TPs.
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Bromobencenos/análisis , Monitoreo del Ambiente , Retardadores de Llama/análisis , Éteres Difenilos Halogenados/análisis , Hidrocarburos Bromados/análisis , Tolueno/análisis , Rayos UltravioletaRESUMEN
The widespread use of hexabromocyclododecane (HBCD), a brominated flame retardant, is a major public health concern because of the toxic, persistent, and bioaccumulative nature of HBCD. However, there is limited information available regarding the distribution and transportation of HBCD in sediments across various environmental settings, spanning from riverine to marine environments in the Kaohsiung area of Taiwan. In this study, we comprehensively investigated the level and distribution of and potential ecological risk posed by HBCD in surface sediments in the Kaohsiung area of Taiwan. In sediment samples from stations on the Love River and Kaohsiung Port area, the concentrations of HBCD ranged from 10.6 to 320.1 µg/kg dry weight (dw) and nondetectable (n.d.) to 58.4 µg/kg dw, respectively. The concentrations of HBCD in sediment collected from the M1, M2, and M3 sites, located in the Cijin coastal area, were 896.2 µg/kg dw, 3.2 µg/kg dw (
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Contaminantes Químicos del Agua , Taiwán , Monitoreo del Ambiente , Hidrocarburos Bromados/análisis , Sedimentos Geológicos , Ríos , Retardadores de Llama/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Spatial and temporal trends of tetrabromobisphenol (TBBPA) and hexabromocyclododecane (HBCD) in mangrove sediments from the Pearl River Estuary (PRE) in South China were evaluated. Concentrations of TBBPA and HBCD in mangrove sediments ranged from 0.23 to 13.3 and 0.36 to 54.7 ng g-1 dry weight. The highest TBBPA concentration was seen in Guangzhou mangrove wetland near a dockyard and a ferry terminal where TBBPA is utilized in the coatings for the shipbuilding industry. The rapid development of building might elucidate the higher concentrations of HBCD in Shenzhen mangrove sediments. γ-HBCD and α-HBCD was the two main diastereoisomer of HBCD in mangrove sediments with contributions of 56.1 % and 34.0 %. Sediments from the three PRE mangrove ecosystems were selectively enriched for (-)-γ-HBCD. TBBPA concentrations in mangrove sediments from Guangzhou rose during 2012-2015 and declined from 2015 to 2021. HBCD concentrations in the PRE mangrove sediments exhibited an increasing trend from 2012 to 2021.
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Bifenilos Polibrominados , Ecosistema , Estuarios , Ríos , Monitoreo del Ambiente , Hidrocarburos Bromados/análisis , Bifenilos Polibrominados/análisis , China , Sedimentos Geológicos , Retardadores de Llama/análisisRESUMEN
We aimed to investigate the relationship between oxidative stress indicators and brominated flame retardant (BFR) levels in US adults. Using data from the NHANES (National Health and Nutrition Examination Survey) from 2007 to 2016, 8028 participants aged 18 and over were enrolled in this study. PBDE28, PBDE47, PBDE85, PBDE99, PBDE100, PBDE153, PBDE154, PBDE209, and PBB153, with over 75 % detection rates, were extracted in this study. Survey-weighted linear regression model, weighted quantile sum (WQS) model, and quantile-based g calculation (QGC) model were used to assess the correlation between serum BFRs levels and oxidative stress indicators (serum bilirubin and gamma-glutamyl transferase [GGT]). Besides, the nonlinear association was explored using restricted cubic splines (RCS). Each of the BFRs was confirmed by the survey-weighted linear regression model to be positively associated with GGT after controlling for variables, and BFRs except for PBDE153 were positively associated with serum bilirubin. Except for PBDE153, serum bilirubin in the highest quartile of BFRs was significantly higher than in the lowest high quartile. Additionally, except for PBDE85, serum GGT in the highest quartile of BFRs was higher than in the lowest high quartile. A significant nonlinear association between all BFRs with bilirubin and the PBDE153, PBDE209, and PBB153 with GGT was identified by RCS analysis. By WQS analysis, combined BFR exposure was associated with serum GGT (ß: 0.093; 95 % CI = 0.066-0.121; P < 0.0001) and bilirubin (ß: 0.090; 95 % CI = 0.068-0.113; P < 0.0001). QGC analysis found a similar correlation between BFR mixtures with serum GGT (ß: 0.098; 95 % CI = 0.075-0.120; P < 0.0001) and bilirubin (ß: 0.073; 95 % CI = 0.048-0.097; P < 0.0001). Exposure to BFRs is positively associated with markers of oxidative stress (serum bilirubin and GGT) in US adults, which needs further exploration by a large-scale cohort study.
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Adulto , Humanos , Adolescente , Retardadores de Llama/análisis , Encuestas Nutricionales , Estudios de Cohortes , Éteres Difenilos Halogenados/análisis , gamma-Glutamiltransferasa , Bilirrubina , Hidrocarburos Bromados/análisisRESUMEN
Brominated flame retardants (BFRs) are a class of compounds with many persistent, toxic, and bioaccumulative members. BFRs have been widely detected in breast milk, posing health risks for breastfeeding infants. Ten years after the phaseout of polybrominated diphenyl ethers (PBDEs) in the United States, we analyzed breast milk from 50 U.S. mothers for a suite of BFRs to assess current exposures to BFRs and the impact of changing use patterns on levels of PBDEs and current-use compounds in breast milk. Compounds analyzed included 37 PBDEs, 18 bromophenols, and 11 other BFRs. A total of 25 BFRs were detected, including 9 PBDEs, 8 bromophenols, and 8 other BFRs. PBDEs were found in every sample but at concentrations considerably lower than in previous North American samples, with a median ∑PBDE concentration (sum of 9 detected PBDEs) of 15.0 ng/g lipid (range 1.46-1170 ng/g lipid). Analysis of time trends in PBDE concentrations in North American breast milk indicated a significant decline since 2002, with a halving time for ∑PBDE concentrations of 12.2 years; comparison with previous samples from the northwest U.S region showed a 70% decline in median levels. Bromophenols were detected in 88% of samples with a median ∑12bromophenol concentration (sum of 12 detected bromophenols) of 0.996 ng/g lipid and reaching up to 71.1 ng/g lipid. Other BFRs were infrequently detected but concentrations reached up to 278 ng/g lipid. These results represent the first measurement of bromophenols and other replacement flame retardants in breast milk from U.S. mothers. In addition, these results provide data on current PBDE contamination in human milk, as PBDEs were last measured in U.S. breast milk ten years ago. The presence of phased-out PBDEs, bromophenols, and other current-use flame retardants in breast milk reflects ongoing prenatal exposure and increased risk for adverse impacts on infant development.
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Lactante , Femenino , Niño , Humanos , Leche Humana/química , Éteres Difenilos Halogenados/análisis , Retardadores de Llama/análisis , Noroeste de Estados Unidos , Lípidos , Monitoreo del Ambiente/métodos , Hidrocarburos Bromados/análisisRESUMEN
The levels and distributions of hexabromocyclododecane diastereoisomers (HBCDs) (including α, ß, and γ-HBCD) and tetrabromobisphenol A (TBBPA) were investigated in indoor dust from bedrooms and offices. HBCDs diastereoisomers were the most abundant compounds in the dust samples, and the concentrations of ∑HBCDs in the bedrooms and offices ranged from 10.6 to 290.1 ng/g and 17.6 to 1521.9 ng/g, respectively. The concentrations of target compounds in the offices were generally higher than those in the bedrooms, probably due to the presence of more electrical equipment in the offices. In this study, highest levels of target compounds were all found in the electronics. In the bedrooms, the highest mean level of ∑HBCDs was found in air conditioning filter dust (118.57 ng/g), while the personal computer table surface dust showed the peak mean concentrations of ∑HBCDs (290.74 ng/g) and TBBPA (539.69 ng/g) in the offices. Interestingly, a significantly positive correlation was observed between the concentrations of ∑HBCDs in windowsills and beddings dust in the bedrooms, suggesting beddings was one of the crucial sources of ∑HBCDs in the bedrooms. The high dust ingestion values of ∑HBCDs and TBBPA were 0.046 and 0.086 ng/kg bw/day for adults, while 0.811 and 0.04 ng/kg bw/day for toddlers, respectively. The high dermal exposure values of ∑HBCDs were 0.026 and 0.226 ng/kg bw/day for adults and toddlers, respectively. Except for dust ingestion, other human exposure pathways (such as the dermal contact with beddings and furniture) should be paid attention.
Asunto(s)
Contaminación del Aire Interior , Retardadores de Llama , Hidrocarburos Bromados , Adulto , Humanos , Exposición a Riesgos Ambientales/análisis , Polvo , Contaminación del Aire Interior/análisis , Hidrocarburos Bromados/análisis , Retardadores de Llama/análisisRESUMEN
The principal objective in the treatment of e-waste is to capture the bromine released from the brominated flame retardants (BFRs) added to the polymeric constituents of printed circuits boards (PCBs) and to produce pure bromine-free hydrocarbons. Metal oxides such as calcium hydroxide (Ca(OH)2) have been shown to exhibit high debromination capacity when added to BFRs in e-waste and capturing the released HBr. Tetrabromobisphenol A (TBBA) is the most commonly utilized model compound as a representative for BFRs. Our coauthors had previously studied the pyrolytic and oxidative decomposition of the TBBA:Ca(OH)2 mixture at four different heating rates, 5, 10, 15, and 20 °C/min, using a thermogravimetric (TGA) analyzer and reported the mass loss data between room temperature and 800 °C. However, in the current work, we applied different machine learning (ML) and chemometric techniques involving regression models to predict the TGA data at different heating rates. The motivation of this work was to reproduce the TGA data with high accuracy in order to eliminate the physical need of the instrument itself, so that this could save significant experimental time involving sample preparation and subsequently minimizing human errors. The novelty of our work lies in the application of ML techniques to predict the TGA data from e-waste pyrolysis since this has not been conducted previously. The significance of our work lies in the fact that e-waste is ever increasing, and predicting the mass loss curves faster will enable better compositional analysis of the e-waste samples in the industry. Three ML models were employed in our work, namely Linear, random forest (RF), and support vector regression (SVR), out of which the RF method exhibited the highest coefficient of determination (R2) of 0.999 and least error of prediction as estimated by the root mean squared error (RMSEP) at all 4 heating rates for both pyrolysis and oxidation conditions. An 80:20 split was used for calibration and validation data sets. Furthermore, for showing versatility and robustness of the best-predicting RF model, it was also trained using all the data points in the lower heating rates of 5 and 10 °C/min and predicted on all the data points for the higher heating rates of 15 and 20 °C/min to again obtain a high R2 of 0.999. The excellent performance of the RF model showed that ML techniques can be used to eliminate the physical use of TGA equipment, thus saving experimental time and potential human errors, and can further be applied in other real-time e-waste recycling scenarios.
Asunto(s)
Residuos Electrónicos , Retardadores de Llama , Hidrocarburos Bromados , Bifenilos Polibrominados , Humanos , Bromo , Residuos Electrónicos/análisis , Retardadores de Llama/análisis , Hidrocarburos Bromados/análisis , Bifenilos Polibrominados/análisis , Aprendizaje AutomáticoRESUMEN
This study investigated the occurrence of hexabromocyclododecanes (HBCDs) in soil-maize system around Baiyangdian Lake. The total concentration of ΣHBCDs was in the order of industrial area > residential area > marginal area > Fuhe River estuary in soil. γ-HBCD was predominated in soils, roots and stems, while α-HBCD was the main diastereoisomer in leaves and kernels. Concentration of ΣHBCDs and three diastereoisomer concentrations in soils were significantly reduced and remained low level from 2018 to 2019. Selectivity enrichment of (+)α- and (-)γ-HBCD was found in soils, roots, stems and leaves, whereas only (+)ß-HBCD dominated in stems. Most of the total root bioaccumulation factors (ΣRCFs) were less than 1.0, but no significant correlation was showed between translocation factors (TFs) and log Kow. RCFs and TFs of enantiomers suggested (-)ß- and (-)γ-HBCD were easily translocated from soil to roots, while (+)α-, (-)ß- and (-)γ-HBCD tended to translocate from stems to leaves. Estimated daily intake (EDI) and of ΣHBCDs, diastereoisomers and enantiomers were all lower than the threshold value, while the Calculated margins of exposure (MOE) were well above the threshold value, which demonstrate the safe consumption of Maize around Baiyangdian Lake.
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Zea mays , Suelo , Lagos , Retardadores de Llama/análisis , Hidrocarburos Bromados/análisis , Estereoisomerismo , China , Monitoreo del AmbienteRESUMEN
The adaptation of microbial community to the long-term contamination of hexabromocyclododecanes (HBCDs) has not been well studied. Our previous study found that the HBCDs contamination in the microcosms constructed of sediments from two different mangrove forests in 8 months resulted in serious acidification (pH2-3). This study reanalyzed previous sequencing data and compared them with data after 20 months to investigate the adaptive properties of microbial communities in the stress of HBCDs and acidification. It hypothesized that the reassembly was based on the fitness of taxa. The results indicated that eukaryotes and fungi might have better adaptive capacity to these deteriorated habitats. Eukaryotic taxa Eufallia and Syncystis, and fungal taxa Wickerhamomyces were only detected after 20 months of contamination. Moreover, eukaryotic taxa Caloneis and Nitzschia, and fungal taxa Talaromyces were dominant in most of microbial communities (14.467-95.941%). The functional compositions were sediment-dependent and more divergent than community reassemblies. Network and co-occurrence analysis suggested that acidophiles such as Acidisoma and Acidiphilium were gaining more positive relations in the long-term stress. The acidophilic taxa and genes involved in resistance to the acidification and toxicity of HBCDs were enriched, for example, bacteria Acidisoma and Acidiphilium, archaea Thermogymnomonas, and eukaryotes Nitzschia, and genes kdpC, odc1, polA, gst, and sod-2. These genes involved in oxidative stress response, energy metabolism, DNA damage repair, potassium transportation, and decarboxylation. It suggested that the microbial communities might cope with the stress from HBCDs and acidification via multiple pathways. The present research shed light on the evolution of microbial communities under the long-term stress of HBCDs contamination and acidification.
Asunto(s)
Hidrocarburos Bromados , Microbiota , Hidrocarburos Bromados/análisis , Eucariontes/metabolismo , Archaea/genética , Archaea/metabolismoRESUMEN
Tetrabromobisphenol A (TBBPA) and hexabromocyclododecane isomers (HBCDs) are widely detected in indoor environments, but the research on the accumulation, contamination, and human exposure of TBBPA and HBCDs in electronic products dust is still limited. It is unclear whether electronic products might pose human health risk via dust ingestion and dermal absorption. In this study, the levels and distributions of TBBPA and HBCDs were investigated in the personal computer (PC) interior dust and PC surface (upper and bottom) wipes. The median concentrations of TBBPA in PC interior dust, upper, and bottom surface wipes were 168.1 ng/g, 13.2 ng/m2, and 15.2 ng/m2, respectively. These levels were generally higher than those of HBCDs, which were 95.2 ng/g, 11.7 ng/m2, and 12.3 ng/m2, respectively. No significant correlations were found among the PC upper and bottom surface wipes, and interior dust, indicating different sources of TBBPA and HBCDs in PC interior and surface dust. The TBBPA and HBCDs in the PC interior dust were mainly released from inner PC materials, while the sources of target compounds on the surface wipes were likely from external environments. The exposure values of two occupational populations (including PC owners and PC repair workers) to TBBPA and HBCDs were measured by PC interior dust and upper surface wipes. The results imply dust ingestion (including hand-to-mouth uptake) is the main contributor of the exposure route to TBBPA and HBCDs for both PC owners and repair workers. Compared to PC owners, PC repair workers showed the greater risk in exposure assessment, which should be paid more attention.
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Humanos , Monitoreo del Ambiente , Polvo/análisis , Retardadores de Llama/análisis , Hidrocarburos Bromados/análisis , MicrocomputadoresRESUMEN
Brominated flame retardants such as polybrominated diphenyl ethers (PBDEs) have been used for decades until evidence of negative health effects led to bans in many countries. PBDEs have since been replaced by alternative legacy compounds or newly developed chemicals. In this study, eight alternative brominated flame retardants were analyzed in blubber and liver of harbor seal pups (≤6 months) from the Northwest Atlantic collected during 2001-2010 to elucidate concentrations, patterns, contamination trends, potential maternal transfer, and tissue partitioning. All compounds were detected in liver and blubber tissues with hexabromocyclododecane (HBCD) isomers and 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB) predominating. Overall, α-HBCD was the dominant HBCD isomer in both tissues although the concentrations of γ-HBCD exceeded those of α-HBCD in seven pups, indicating their mothers may have had alternative dietary patterns or recent exposure to the commercial mixture. Although it was detected in less than half of the samples, to our knowledge, this is the first study to report tetrabromobisphenol A (TBBPA) concentrations in multiple tissues of a top marine predator. For the brominated components of Firemaster® flame retardants, TBB concentrations exceeded bis-(2-ethylhexyl)-tetrabromophthalate (TBPH). This pattern may result from recent exposure to commercial mixtures in which TBB exceeds TBPH 4:1 or from differences in perinatal or lactational transfer efficiency of the two compounds. Between the two tissues, lipid-normalized ß-HBCD, γ-HBCD, TBB and decabromodiphenyl ethane (DBDPE) concentrations were significantly higher in liver than blubber. This indicates that the bioaccumulation of these chemicals is not simply related to lipid dynamics but may be linked to blood proteins. This study demonstrates that harbor seal pups from this region are contaminated with alternative flame retardants passed to them via placental or lactational transfer. Given the evidence for negative health effects of these chemicals, this contamination adds additional pressure on the first year survival of these young, developing animals.
Asunto(s)
Retardadores de Llama , Hidrocarburos Bromados , Phoca , Embarazo , Animales , Femenino , Phoca/metabolismo , Monitoreo del Ambiente , Retardadores de Llama/análisis , Éteres Difenilos Halogenados/análisis , Placenta/metabolismo , Hidrocarburos Bromados/análisis , LípidosRESUMEN
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.