Elucidating toxicity mechanisms of hexabromocyclododecane in marine microalga Chlorella salina: An integrated biomacromolecular and transcriptomic analysis.

Untargeted lipidomic profiling reveals the effect of hexabromocyclododecane exposure on a branching coral.

Development of a LC-MS/MS method for the determination of tetrabromobisphenol A-bis(2,3-dibromo-2-methylpropyl ether) and co-occurring brominated flame retardant in building insulation foam and environmental matrices.

Purification technologies that remove contaminants from waste plastics are critical to increasing plastic recyclability. Mechanical recycling cannot remove embedded additives, dissolution methods are limited by additive–polymer compatibility and chemical recycling requires strict control of contamination to prevent undesired reactions. This work introduces a membrane-based size-exclusion process that exploits a key property of plastics: polymer molecules typically have a molecular weight significantly higher than that of common additives. A case study using ceramic tubular ultrafiltration membranes demonstrates removal of over 90% of hexabromocyclododecane (HBCD) from both virgin and post-consumer polystyrene, while also eliminating polymer tailings originating from degraded polymer chains. By targeting the size difference between polymers and additives, this approach opens new opportunities for regeneration of plastics and offers a pathway to broader recyclability. Applied to common plastics such as PE, PP, PS, PVC, and PU, this framework could increase the fraction of recycled plastics from ~9% to over 68.5%.

Exposure to brominated flame retardants during pregnancy and lactation increases the prevalence of breast lesions and cancer-associated pathways in sprague-dawley rats.

Electronic waste releases brominated fire retardants such as hexabromocyclododecane (HBCD) into the environment during the recycling and dismantling process. This study presents the first integrated assessment of the ecological and human health risks associated with HBCD in soils from e-waste dismantling areas. It offers a comprehensive investigation into the concentration, distribution, and diastereomer profiles of HBCD across different land-use types. This study investigated the contamination levels of HBCD in 51 soil samples collected from an e-waste dismantling area in Qingyuan, Guangdong Province, China. The concentrations of ΣHBCD (the sum of α-, β-, and γ-HBCD) ranged from 0.05 to 27.47ng/g dry weight (dw), with a mean value of 2.10ng/g dw. Significant differences were observed in the levels and profiles of HBCD diastereomers across various land-use areas. The levels of HBCD were significantly influenced by e-waste dismantling and industrial activities. The estimated mean mass stock of HBCD in soil is 63ng/cm2, with a total environmental burden of 199kg in Qingyuan City. The risk quotient values of HBCD ranged from 0.01 to 1; however, two sampling points in the industrial area exceeded a value of 1, indicating a potential risk. The total daily intake of HBCD from soil ranged from 5.16 × 10-4 to 1.7ng/kg-bw/day, which is lower than the dietary intake levels of HBCD reported in China. Nevertheless, non-dietary intake as an important pathway for humans to exposure to HBCD in e-waste dismantling areas cannot be ignored. Infants, as a high-exposure group, exhibit significantly higher non-dietary intake levels of HBCD compared to other age groups. These findings not only advance our understanding of HBCD contamination in e-waste areas but also provide crucial scientific evidence for developing targeted environmental management and pollution control strategies.

Mangrove ecosystems are increasingly threatened by halogenated organic contaminants (HOCs), posing a significant threat to resident arthropods, including spiders and insects. Spider webs, due to their distinctive chemical composition and adsorption properties, have emerged as promising tools for monitoring environmental pollutant. This study quantified 58 HOCs in insects, spider tissues, and webs of Nephila pilipes across mangroves with varying pollution levels, using quantitative fatty acid signature analysis (QFASA) to estimate spider diets. Significantly elevated concentrations of dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexanes (HCHs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), alternative halogenated flame retardants (AHFRs), hexabromocyclododecanes (HBCDs), and tetrabromobisphenol A (TBBPA) were observed in all matrixes from heavily polluted areas, driven by habitat contamination and dietary intake. Concentrations of HCHs, PCBs, PBDEs, and AHFRs in spider webs were highly correlated with those in spider tissues (cephalothorax and abdomen; p < 0.05), whereas DDTs and HBCDs exhibited weak correlations (only in the abdomen; p < 0.05), and TBBPA showed no significant correlation, potentially attributed to compound-specific properties and web characteristics. Integration of HOC concentrations in spider webs with chemical properties (log KOW, log KOA, and molecular weight) yielded significant correlations with biomagnification factors (R2 = 0.415-0.539, p < 0.01) and with tissue HOC levels (R2 = 0.511-0.795, p < 0.001), supporting predictive models for biomagnification and tissue partitioning. These findings underscore the potential of spider webs as noninvasive, sustainable bioindicators that integrate pollutant data to enhance ecological risk assessments and pollution monitoring in sensitive ecosystems, providing a viable alternative to destructive sampling.

Stereoisomer-specific bacterial mechanisms for hexabromocyclododecane biotransformation.

Understanding arbuscular mycorrhizal fungi's contribution to hexabromocyclododecane metabolism: Pathways and ecological implications in contaminated environments.

Intersecting circular economy and child health: A scoping review of legacy brominated flame retardants in plastic childcare products and toys.

Enhanced microbial degradation of hexabromocyclododecane in riparian sediments through regulating flooding regimes.

Brominated flame retardants (BFRs) are persistent organicpollutantscommonly encountered in plastics. Herein, we report on the quantificationof BFRs directly from plastic samples via direct insertion probe massspectrometry (DIP-MS). The study was conducted using model polymersamples comprising either acrylonitrile butadiene styrene copolymer(ABS) or high impact polystyrene (HIPS) and a BFR, namely decabromodiphenylether (decaBDE), hexabromocyclododecane (HBCD), or tetrabromobisphenolA (TBBPA). DIP-MS enabled direct quantification of decaBDE and TBBPAfrom both ABS and HIPS matrices. A linear correlation between BFRsignal intensity and bromine (Br) content of the samples, as determinedby X-ray fluorescence, was established over a Br concentration rangeof 0–7 wt %, or even higher. While DIP-MS showed potentialfor HBCD analysis as well, its effectiveness for quantitative HBCDdetermination remains partly uncertain due to the observed reactivityof HBCD during sample preparation. The detection limits for all studiedBFRs were below 500 mg Br/kg. Additionally, the study shed light onmatrix effects related to additive analysis by DIP-MS, revealing thatthe polymer and other additives can affect BFR volatilization andreactivity. Overall, DIP-MS demonstrated significant potential forthe rapid quantification of BFRs from plastic samples with minimalsample preparation, which is imperative for promoting more efficientplastic recycling.

China used to be the major producer and consumer of hexabromocyclododecanes (HBCDs). Although HBCDs are restricted under the Stockholm Convention, emissions from the flame-retarded materials will continue for several decades and be potentially long-term sources of HBCDs leaching to the environment, and their adverse effects on human health and the environment will continue to raise concerns globally. The levels and distribution of HBCDs in soils of different land use types in the prosperous and densely populated Yangtze River Delta region, China were investigated. The total HBCD concentrations (ΣHBCDs) ranged between 0.17 and 6.28ngg-1dw (dry weight) with a mean value of 1.20ngg-1dw, which was at a low level worldwide. The three HBCD stereoisomers, α-HBCD, β-HBCD and γ-HBCD contributed 37%, 11% and 52% on average, respectively. The spatial distribution of HBCDs showed that northern and southern Jiangsu regions had higher HBCD levels than those in central region. HBCD contamination differed considerably among three type of lands, industrial land > urban and commercial land > agricultural and suburban land, suggesting that anthropogenic activities such as industrial production, urbanization and commercial activities etc. are the major sources of HBCDs, especially the influence of industries. No relationships were found between HBCD concentrations and per capita GDP (gross domestic product) in northern Jiangsu, while they were significantly positively correlated in southern Jiangsu. Mass inventory of HBCDs in the surface soils of Jiangsu was 38.6 tons. The estimated daily intakes (EDIs) of HBCDs for human via soil ingestion were 0.75, 1.68-3.77, 7.83-12.9pgkg-1bwd-1 for ages > 21, 6 to 21years and under 6years, respectively. The mean EDIs for children under 6years old was approximately 13 times greater than that of adult.

Transcriptome analysis reveals the different toxic mechanism of three HBCD diastereoisomers to Brachionus plicatilis based on chemical defensome.

The limitation of legacy hexabromocyclododecanes (HBCDs) and increasing usage of emerging brominated flame retardant (BFR) tetrabromobisphenol A (TBBPA) resulted in their co-exposure to organisms. In this study, domestic chicken and environmental samples collected near a BFR manufacturing zone were analyzed to determine the bioaccumulation and transfer of HBCDs and TBBPA. The mean concentrations of ∑3HBCDs, TBBPA, ∑4TBBPA-related derivatives, ∑9TBBPA-related byproducts, and ∑16TBBPA-related transformation products in chicken tissues were 1207, 0.20, 15087, 0.96, and 6384 ng/g lipid weight, respectively. Exposure to sources of BFR contamination (soil, feed, and water) could be the main cause of high BFR levels in chickens. α-HBCD and bis-substituted TBBPA analogues have higher bioaccumulation factor levels than TBBPA and other compounds, indicating greater bioconcentration potential for substances with higher logK ow. HBCDs, TBBPA, and TBBPA analogues tend to be enriched in the chicken comb and spleen and can cross the blood-brain barrier into the brain. However, while these compounds accumulate in the mother, they are also subject to metabolic processes that lead to their eventual excretion. Low-persistence BFRs were more favorable to maternal transfer, while compounds with high persistence tended to be retained in the mother. Although dietary intake of BFRs through chicken consumption poses a low risk to the general population, concerns remain regarding the synergistic risk of BFRs.

There are currently no available cell lines for the ecologically relevant colonial waterbird species, the double-crested cormorant (DCCO). DCCOs are high trophic level aquatic birds that are used for routine contaminant monitoring programs in the Laurentian Great Lakes and marine coasts of Canada. Developing a DCCO cell line for in vitro toxicological screening will ideally provide improved understanding of the effects of environmental chemicals given the large differences in sensitivity between laboratory and wild avian species. In this study, an immortalized DCCO hepatic cell line, DCH22, was established from the liver of a day 22 female embryo as a potential alternative to primary DCCO embryonic hepatocytes (DCEH) for chemical screening. DCH22 cells were cultured for over a year and have hepatocyte-like morphology. Exposure to 3,3',4,4',5-pentachlorobiphenyl (PCB-126), benzo-a-pyrene, ß-napthoflavone and phenacetin induced CYP1A activity and mRNA expression in DCH22 3D spheroids. Induction of CYP3A activity and mRNA expression was observed following exposure to hexabromocyclododecane (HBCD), tris(1,3-dichloroisopropyl)phosphate, carbamazepine, and metyrapone. The phase II metabolism gene, UGT1A1, was upregulated following HBCD exposure and DCH22 spheroids expressed vitellogenin protein after exposure to 17α-ethinylestradiol. Based on these data, the novel DCH22 cell line, cultured as 3D spheroids, has potential use as an alternative to DCEH for chemical screening and will permit the evaluation of avian species differences in sensitivity from an in vitro screening perspective.

Occurrence and distribution of brominated and fluorinated persistent organic pollutants in surface sediments focusing on industrially affected rivers.

Hexabromocyclododecane (HBCD) is a brominated flame retardant, that is added, but not chemically bonded, to consumer products. HBCD is sold as a commercial-grade HBCD mixture containing three major stereoisomers: alpha (α), beta (β), and gamma (γ), with relative amounts of 12% for α-HBCD, 6% for β-HBCD, and 82% for γ-HBCD. HBCDs are widely measured in the environment and in biological matrices. The toxicological effects of its exposure in humans are not clearly understood. A recent reassessment pointed out potential thyroid disruption as a primary effect. This current work aims to update a physiologically based pharmacokinetic (PBPK) model for γ-HBCD in C57BL/6 mice and incorporate equations and codes for α-HBCD and β-HBCD isomers and simulate them as a mixture. Physiological parameters were taken from the literature, calculated based on the log Kow or optimized with the dataset. The elimination of HBCDs in urine and feces was optimized to reflect the percent dose excreted, as published in the literature. Compared with data from the literature for α-HBCD, β-HBCD, and γ-HBCD in multiple tissues, the model simulations accurately described the pharmacokinetics of HBCDs in the mouse. The utility of the model was demonstrated by predicting blood concentrations from three studies in adult mice evaluating dopaminergic changes in the brain. Although this PBPK model for the mixture explicitly describes α-HBCD, β-HBCD, and γ-HBCD as individual exposures, but also as a mixture, more experimental data with commercial HBCD mixtures is still needed to improve the model.

E-waste, a global environmental concern, particularly affects developing nations due to the rise in informal recycling practices. This leads to contamination of environmental matrices, posing threats to both ecosystems and human health. To assess this issue, we monitored brominated flame retardants (BFRs) in 164 samples (soil) from 32 informal e-waste operational locations and 9 background locations across nine mega cities of Pakistan from September 2020 to December 2021. The mean concentrations (ng/g) of ∑27PBDEs (polybrominated diphenyl ethers), ∑2PBB (polybrominated biphenyls), HBB (hexabromobiphenyl), and ∑HBCDD (hexabromocyclododecane) were 176 ( 0.76-11141), 31.0 (0.65-58.0), 1.39 (0.01-42.8), and 12.0 (0.22-461), respectively. These levels were significantly higher (6 to tenfold) than those at background sites. Karachi, Faisalabad, Gujranwala, and Lahore exhibited high levels of all BFRs. Notably, BDE-209 (mean = 45.5ng/g) ranged (0.13-1152ng/g) exhibited higher level in soil samples. Seasonally, total ΣBFR concentrations (ng/g) ranked higher in winter (11,620), followed by spring (3874), autumn (3139), and summer (1207) indicating a seasonal impact of recycling activities. The average daily dose for soil ingestion (ng/kg/day) was estimated for BDE-209 (0.10973) in Faisalabad, followed by BDE-47 (0.08616) and BDE-99 (0.06788) in Karachi. Our findings showed that these values were lower than RfD values, suggesting no ingestion risk from studied BFRs. However, the growing prevalence of such informal e-waste recycling facilities could lead to increased exposure to toxic chemicals in near future.

Occurrence and risk of microplastics and hexabromocyclododecane in urban drinking water systems: From source water to tap water.