PM2.5-Bound Organophosphate Flame Retardants in Hong Kong: Occurrence, Origins, and Source-Specific Health Risks.

Organophosphate flame retardants (OPFRs) are emerging organic pollutants in PM2.5, which have caused significant public health concerns in recent years, given their potential carcinogenic and neurotoxic effects. However, studies on the sources, occurrence, and health risk assessment of PM2.5-bound OPFRs in Hong Kong are lacking. To address this knowledge gap, we characterized 13 OPFRs in one-year PM2.5 samples using gas chromatography-atmospheric pressure chemical ionization tandem mass spectrometry. Our findings showed that OPFRs were present at a median concentration of 4978 pg m-3 (ranging from 1924 to 8481 pg m-3), with chlorinated OPFRs dominating and accounting for 82.7% of the total OPFRs. Using characteristic source markers and positive matrix factorization, we identified one secondary formation and five primary sources of OPFRs. Over 94.0% of PM2.5-bound OPFRs in Hong Kong were primarily emitted, with plastic processing and waste disposal being the leading source (61.0%), followed by marine vessels (14.1%). The contributions of these two sources to OPFRs were more pronounced on days influenced by local pollution emissions (91.9%) than on days affected by regional pollution (44.2%). Our assessment of health risks associated with human exposure to PM2.5-bound OPFRs indicated a low-risk level. However, further source-specific health risk assessment revealed relatively high noncarcinogenic and carcinogenic risks from chlorinated OPFRs emitted from plastic processing and waste disposal, suggesting a need for more stringent emission control of OPFRs from these sources in Hong Kong.

Temporal Trends of Legacy and Current-Use Halogenated Flame Retardants in Lake Ontario in Relation to Atmospheric Loadings, Sources, and Environmental Fate.

Since the phase-out of polybrominated diphenyl ethers (PBDEs), large amounts of alternative halogenated flame retardants (AHFRs) have been introduced to the market. Due to their persistence and toxicity, halogenated flame retardants (HFRs) have become a concern for the ecosystem and human health. However, there remains limited assessment of the atmospheric loadings, sources, and environmental fate of HFRs in Lake Ontario, which receives urban-related inputs and cumulative chemical inputs from the upstream Great Lakes from Canada and the United States. We combined long-term measurements with a modified multimedia model based on site-specific environmental parameters from Lake Ontario to understand the trends and fate of HFRs. All HFRs were detected in the air, precipitation, lake trout, and herring gull egg samples throughout the sampling periods. General decreasing trends were found for PBDEs, while the temporal trends for AHFRs were not clear. Physical-chemical properties and emissions significantly influence the levels, profiles, and trends. Using the probabilistic modeling, HFR concentrations in lake water and sediment were predicted to be close to the measurement, suggesting a good performance for the modified model. The loadings from tributaries and wastewater effluent were the primary input pathways. Transformations in the water and sedimentation were estimated to be the dominant output pathway for the three HFRs.

Multifunctional Textiles with Flame Retardant and Antibacterial Properties: A Review.

It is well known that bacterial infections and fire-hazards are potentially injurious in daily life. With the increased security awareness of life and properties as well as the improvement of living standards, there has been an increasing demand for multifunctional textiles with flame retardant and antibacterial properties, especially in the fields of home furnishing and medical protection. So far, various treatment methods, including the spray method, the dip-coating method, and the pad-dry-cure method, have been used to apply functional finishing agents onto fabrics to achieve the functionalization in the past exploration stage. Moreover, in addition to the traditional finishing technology, a number of novel technologies have emerged, such as layer-by-layer (LBL) deposition, the sol-gel process, and chemical grafting modification. In addition, some natural biomasses, including chitin, chitosan (CS), and several synthetic functional compounds that possess both flame-retardant and bacteriostatic properties, have also received extensive attention. Hence, this review focuses on introducing some commonly used finishing technologies and flame retardant/antibacterial agents. At the same time, the advantages and disadvantages of different methods and materials were summarized, which will contribute to future research and promote the development and progress of the industry.

Levels of organophosphate flame retardants and their metabolites among 391 volunteers in Taiwan: difference between adults and children.

Background: Organophosphate flame retardants (OPFRs) are ubiquitous in the environment. The compositions and concentrations of different OPFRs metabolites vary in different environments depending on different human activities. The objective of the present study was to evaluate the exposure of different age groups to OPFRs in Taiwan. Methods: Volunteers provided urine samples and responded to questionnaires including demographic factors, underlying disease, lifestyle information, and occupation from October 2021 to January 2022. OPFR measurements were performed using a Waters Acquity Ultra-Performance Liquid Chromatography system coupled with a Waters Xevo TQ-XS mass spectrometer. Results: A total of 391 volunteers (74 children and 317 adults) were enrolled in this study. The concentrations (presented as µg/g creatinine) of bis(1,3-dichloro-2-propyl) phosphate (BDCPP, p = 0.029) and tri-n-butyl phosphate (TNBP, p = 0.008) were higher in the adult group, while the concentrations of bis-2-chloroethyl phosphate (BCEP, p = 0.024), diphenyl phosphate (DPHP, p < 0.001), tris(1,3-dichloro-2-propyl) phosphate (TDCPP, p = 0.009), and Tris(2-butoxyethyl) phosphate (TBEP, p = 0.007) were higher in the child group. Compared with school age children (>6 years), the concentration of di(2-n-butoxyethyl) phthalate (DBEP, 1.14 vs. 0.20 µg/g creatinine, p = 0.001), DPHP (1.23 vs. 0.54 µg/g creatinine, p = 0.036), TBEP (1.63 vs. 0.29 µg/g creatinine, p < 0.001), and the sum of OPFR metabolites (ΣOPFRs, 6.58 vs. 2.04 µg/g creatinine, p < 0.001) were statistically higher in preschool-aged children. After adjusting for confounding factors, pre-school age [odds ratio (OR): 4.579, 95% confidence interval (CI): 1.389-13.115] and current smoker (OR: 5.328, 95%CI: 1.858-14.955) were independently associated with the risk of ΣOPFRs higher than 90 percentile. Conclusion: This study revealed the distribution of different OPFRs metabolites in children and adults. DBEP, DPHP, TBEP, and ΣOPFR were higher in preschool-aged children. Pre-school age and current smoking status were independent risk factors for ΣOPFRs higher than 90 percentile.

Insight into Bioaccumulation of Decabromodiphenyl Ethane in Eisenia fetida Increased by Microplastics.

The rise of electronics inevitably induced the co-pollution of novel brominated flame retardants (NBFRs) and microplastics (MPs). However, studies on how they interact to influence their bioavailability are scarce. Here, we explored the influence mechanism of acrylonitrile butadiene styrene (ABS)-MPs on the bioaccumulation of decabromodiphenyl ethane (DBDPE) in soil-earthworm microcosms. The influence exhibited a temporal pattern characterized by short-term inhibition and long-term promotion. After 28 days of exposure, DBDPE bioaccumulation in a co-exposure (10 mg kg-1 DBDPE accompanied by 1000 mg kg-1 ABS-MPs) was 2.61 times higher than that in a separate exposure. The adsorption process in the soil, intestines, and mucus introduced DBDPE-carried MPs, which had a higher concentration of DBDPE than the surrounding soil and directly affected the bioavailability of DBDPE. MP-pre-exposure (100, 1000, and 10000 mg kg-1) reduced epidermal soundness, mucus secretion, and worm cast production. This eventually promoted the contact between earthworm and soil particles and enhanced the DBDPE of earthworm tissue by 6%-61% in the next DBDPE-postexposure period, confirming that MPs increased DBDPE bioaccumulation indirectly by impairing the earthworm health. This study indicates that MPs promoted DBDPE bioaccumulation via adsorption and self-toxicity, providing new insight into the combined risk of MPs and NBFRs.

International Comparison, Risk Assessment, and Prioritisation of 26 Endocrine Disrupting Compounds in Three European River Catchments in the UK, Ireland, and Spain.

Endocrine-disrupting compounds (EDCs) constitute a wide variety of chemistries with diverse properties that may/can pose risks to both humans and the environment. Herein, a total of 26 compounds, including steroids, flame retardants, and plasticizers, were monitored in three major and heavily urbanized river catchments: the R. Liffey (Ireland), the R. Thames (UK), and the R. Ter (Spain), by using a single solid-phase extraction liquid chromatography-mass spectrometry (SPE-LC-MS/MS) method. Occurrence and frequency rates were investigated across all locations over a 10-week period, with the highest concentration obtained for the flame retardant tris(2-chloroethyl) phosphate (TCEP) at 4767 ng∙L-1 in the R. Thames in Central London. Geographical variations were observed between sites and were partially explained using principal component analysis (PCA) and hierarchical cluster analysis (HCA). In particular, discrimination between the R. Ter and the R. Thames was observed based on the presence and concentration of flame retardants, benzotriazole, and steroids. Environmental risk assessment (ERA) across sites showed that caffeine, a chemical marker, and bisphenol A (BPA), a plasticizer, were classified as high-risk for the R. Liffey and R. Thames, based on relative risk quotients (rRQs), and that caffeine was classified as high-risk for the R. Ter, based on RQs. The total risks at each location, namely ΣRQriver, and ΣrRQriver, were: 361, 455, and 723 for the rivers Liffey, Thames, and Ter, respectively. Caffeine, as expected, was ubiquitous in all 3 urban areas, though with the highest RQ observed in the R. Ter. High contributions of BPA were also observed across the three matrices. Therefore, these two compounds should be prioritized independently of location. This study represents a comprehensive EDC monitoring comparison between different European cities based on a single analytical method, which allowed for a geographically independent ERA prioritization to be performed.

Interactions of organophosphate flame retardants with human drug transporters.

Organophosphate flame retardants (OPFRs) are environmental pollutants of increasing interest, widely distributed in the environment and exerting possible deleterious effects towards the human health. The present study investigates in vitro their possible interactions with human drug transporters, which are targets for environmental chemicals and actors of their toxicokinetics. Some OPFRs, i.e., tris(2-butoxyethyl) phosphate (TBOEP), tris(1,3-dichloroisopropyl) phosphate (TDCPP), tri-o-cresyl phosphate (TOCP) and triphenyl phosphate (TPHP), were found to inhibit activities of some transporters, such as organic anion transporter 3 (OAT3), organic anion transporting polypeptide (OATP) 1B1, OATP1B3, organic cation transporter 2 (OCT2) or breast cancer resistance protein (BCRP). These effects were concentration-dependent, with IC50 values ranging from 6.1 µM (for TDCPP-mediated inhibition of OCT2) to 51.4 µM (for TOCP-mediated inhibition of BCRP). OPFRs also blocked the transporter-dependent membrane passage of endogenous substrates, notably that of hormones. OAT3 however failed to transport TBOEP and TPHP. OPFRs additionally repressed mRNA expressions of some transporters in cultured human hepatic HepaRG cells, especially those of OAT2 and OCT1 in response to TOCP, with IC50 values of 2.3 µM and 2.5 µM, respectively. These data therefore add OPFRs to the expanding list of pollutants interacting with drug transporters, even if OPFR concentrations required to impact transporters, in the 2-50 µM range, are rather higher than those observed in humans environmentally or dietarily exposed to these chemicals.

Tributyl phosphate can inhibit the feeding behavior of rotifers by altering the axoneme structure, neuronal coordination and energy supply required for motile cilia.

Organophosphorus flame retardants (OPFRs) are frequently detected in aquatic environments and can potentially amplify the food chain, posing a potential risk to organisms. Marine invertebrates have primitive nervous systems to regulate behavior, but how they respond to OPFRs that are potentially neurotoxic substances is unclear. This study assessed changes in the feeding behavior of rotifer Brachionus plicatilis exposed to alkyl OPFRs tributyl phosphate (TnBP) (0.376 nM, 3.76 and 22.53 µM) to elucidate the mechanism of behavioral toxicity. TnBP at 22.53 µM reduced the ingestion and filtration rates of rotifers for Chlorella vulgaris and Phaeocystis globosa in a 24-h test and altered rotifer-P. globosa population dynamics in 15-d coculture. Ciliary beat frequency was also reduced, and the expression of genes encoding the cilia axoneme was downregulated. TnBP could inhibit rotifer acetylcholinesterase activity by binding this protein and reduce the expression of the exocytotic membrane protein syntaxin-4, suggesting a disorder in nervous regulation of cilia beat. Moreover, TnBP induced abnormal shape and dysfunction of mitochondria, which caused insufficient energy required for ciliary movement. This study revealed diverse neurotoxicity mechanisms of TnBP, particularly as a potentially competing acetylcholinesterase ligand for aquatic invertebrates. Our research also provides a meaningful reference for OPFR-induced behavioral toxicity assessments.

Effects of nitrogen stress on uptake and translocation of organophosphate esters by watermifoil (Myriophyllum aquaticum L.) in an aquatic ecosystem.

Although organophosphate esters (OPEs) and nitrogen (N) are normally present in aquatic environments, the effects of the plant uptake, accumulation, and translocation of OPEs in different levels of N remain ambiguous. To better understand these processes, watermifoil (Myriophyllum aquaticum L.) as tested plant was chosen to investigate the effects of different N levels on the uptake and translocation of OPEs by plants in matched water-sediment-plant samples. After two months, we found the root-water concentration factors, root-sediment concentration factors, and translocation factors (TFs) were significantly changed with the levels of N (p < 0.05), implying that the presence of N could alter uptake, accumulation, and translocation of OPEs in M. aquaticum, particularly the process of root absorption. Low concentrations of N could remarkably promote the uptake of OPEs by M. aquaticum. However, when the concentrations of N in water were higher than 200 mg/L, the plants' growth and OPE accumulation by M. aquaticum were obviously inhibited with the elevated N contents. Moreover, the enrichment and environmental transport of OPEs in M. aquaticum seemed to be closely associated with physicochemical parameters; the octanol-water partition coefficient had significant relationships with measured organic carbon-normalized sediment-water partition coefficients and TFs in the present study. Additionally, the substituents and structures of OPEs could also affect the accumulation and translocation of OPEs in M. aquaticum, including the chlorination degree and alkyl chain length. This study could improve our understanding of uptake and translocation of OPEs in aquatic plants under different levels of N.

Health Risk Assessment of Organophosphate Flame Retardants in Soil Across China Based on Monte Carlo Simulation.

Health risks from exposure to contaminants are generally estimated by evaluating concentrations of the contaminants in environmental matrixes. However, accurate health risk assessment is difficult because of uncertainties regarding exposures. This study aims to utilize data on the concentrations of organophosphate flame retardants (OPFRs) in surface soil across China coupled with Monte Carlo simulations to compensate for uncertainties in exposure to evaluate the health risks associated with contamination of soil with this class of flame retardants. Results revealed that concentrations of ∑OPFRs were 0.793-406 ng/g dry weight (dw) with an average of 23.2 ng/g dw. In terms of spatial distribution, higher OPFRs concentrations were found in economically developed regions. Although the values of health risk of OPFRs in soil across China were below the threshold, the high concentrations of OPFRs in soil in some regions should attract more attentions in future. Sensitivity analysis revealed that concentrations of OPFRs in soil, skin adherence factor, and exposure duration were the most sensitive parameters in health risk assessment. In summary, the study indicated that the national scale soil measurement could provide unique information on OPFRs exposure and health risk assessment, which was useful for the management of soil in China and for better understanding of the environmental fate of OPFRs in the global perspective.

Measuring semi-volatile organic compound exposures during pregnancy using silicone wristbands.

Silicone wristbands were utilized as personal passive samplers in a sub-cohort of 92 women, who participated in New York University Children's Health and Environment Study, to assess exposure to semi-volatile organic compounds (SVOCs). Wristbands were analyzed for 77 SVOCs, including halogenated and non-halogenated organophosphate esters (OPEs), polychlorinated biphenyls (PCBs), pesticides, phthalates, and brominated flame retardants (BFRs) (e.g. polybrominated diphenyl ethers (PBDEs)). This study aimed to look for patterns in chemical exposure utilizing participant demographics gathered from a questionnaire, and chemical exposure data across multiple timepoints during pregnancy. Analysis focused on 27 compounds detected in at least 80% of the wristbands examined. The chemicals detected most frequently included two pesticides, eight phthalates, one phthalate alternative, seven BFRs, and nine OPEs, including isopropylated and tert-butylated triarylphosphate esters (ITPs and TBPPs). Co-exposure to different SVOCs was most prominent in compounds that were within the same chemical class or were used in similar consumer applications such as phthalates and OPEs, which are often used as plasticizers. Pre-pregnancy BMI was positively associated with multiple compounds, and there were both positive and negative associations between women's parity and SVOC exposure. Outdoor temperature was not correlated with the wristband concentrations over a five-day sampling period. Lastly, significant and moderately high Intraclass Correlation Coefficient (ICC) (0.66-0.84) values for phthalate measurementsacross pregnancy indicate chronic exposure and suggest that using wristbands during one sampling period may reliably predict exposure. However, multiple sampling periods may be necessary to accurately determine indoor exposure to other SVOCs including OPEs and BFRs.

Spatial and temporal change of tetrabromobisphenol A and hexabromocyclododecane in mangrove sediments from the Pearl River Estuary, South China.

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.

Occurrence and accumulation characteristics of legacy and novel brominated flame retardants in surface soil and river sediments from the downstream of Chuhe River basin, East China.

Surface soil and river sediment samples were collected from the downstream of Chuhe River basin, East China, to investigate the occurrence and accumulation characteristics of legacy and novel brominated flame retardants (NBFRs). The respective concentrations of BDE-209 and nine NBFRs ranged from n.d. to 41.4 ng/g dry weight (dw) and from 0.35 to 362.78 ng/g dw in the collected surface soil samples and ranged from 0.29 to 19.73 ng/g dw and from 0.70 to 66.83 ng/g dw in the collected river sediment samples. Soil samples exhibited a higher potential to accumulate BTBPE while the relative abundance of PBT in the collected sediment samples was significantly higher than that in soils. Even so, BTBPE was the predominant NBFR in both soil and sediment samples. The concentrations and relative abundances of legacy and NBFRs exhibited large spatial variation. The calculated concentration ratios of the total of the nine NBFRs (∑9NBFRs) to BDE-209 (∑9NBFRs/BDE-209) in most of the analyzed samples far exceeded 1, implying a clear shift from legacy brominated flame retardants to NBFRs in the downstream of Chuhe River basin.

Two halogenated flame retardants and cadmium in the soil-rice system: sorption, root uptake, and translocation.

The migration and transformation of Tetrabromobisphenol A (TBBPA), DechloranePlus (DP), and cadmium in soil-rice system was investigated, and the influence on the quality of two varieties of rice was studied. The degradation half-lives of TBBPA, BBPAs, syn-DP, and anti-DP were 23.18 ~ 26.36 days, 30.14 ~ 36.10 days, 72.96-81.55 days, and 169.06-198.04 days in the soil. TBBPA was gradually degraded to tri-BBPA, di-BBPA, mono-BBPA, and bisphenol A by the debromination. TBBPA and its bromide metabolites could be bioaccumulated in different tissues of rice; mono-BBPA and bisphenol A was easy to accumulate in the stems, and bisphenol A was easy to bioaccumulate in the grain. Comparing with single and compound pollution, there was no significant difference in bioaccumulation factors of two rice species. The grain of NO7 had stronger bioaccumulation ability to mono-BBPA and BPA than NO1, and there is no significant difference in TBBPA. Residual level of DP in the rice: roots > stems > grain; there was no significant difference in bioaccumulation of two varieties of rice. Cadmium was easily bioaccumulated in the roots of rice and translocated to the rice stems and grains. NO7 rice had stronger bioaccumulation and transport capacity than NO1. The effects of the three pollutants on the quality of two varieties of rice varied significantly; cadmium had the greatest effect on the iodine blue value (BV) and amylase activity of the grain. This study proved that selecting rice varieties with low bioaccumulation to polluters can effectively reduce the risk of the food chain harming human health.

Combating toxic emissions from thermal recycling of polymeric fractions laden with novel brominated flame retardants (NBFRs) in e-waste: an in-situ approach using Ca(OH)2.

Legacy brominated flame retardants (BFRs) in printed circuit boards are gradually being replaced by novel BFRs (NBFRs). Safe disposal and recycling of polymeric constituents in the polymeric fractions of e-waste necessitate the removal of their toxic and corrosive bromine content. This is currently acquired through thermal recycling operations involving the pyrolysis of BFRs-containing materials with metal oxides. Nonetheless, the debromination capacity toward NBFRs is yet to be established. Thus, this study aims to address these two crucial gaps in the current knowledge pertaining to the plausible formation of brominated toxicants from the thermal decomposition of NBFRs and their thermal recycling potential. Herein, we investigate the pyrolysis of a mixture of 2,4,6-tribromophenol (TBP), allyl 2,4,6-tribromophenyl ether (ATE) and Tetrabromobisphenol A-bis (2,3-dibromo propyl ether) (TBBPA-DBPE) in the presence of acrylonitrile butadiene styrene (ABS) polymers at various loads. To demonstrate a viable debromination route, pyrolysis of NBFRs-ABS mixture with Ca(OH)2 was also investigated. The latter is a potent debromination agent for legacy BFRs. Upon pyrolysis with Ca(OH)2, the bromine content in the collected oil was reduced up to 80.49% between 25-500 °C. Products of the co-pyrolysis process generally feature non-brominated aromatic and aliphatic compounds; a finding that indicates an effective thermal recycling approach. As evident by IC measurements, no HBr emission could be detected when Ca(OH)2 is added to the mixture. As XRD patterns show, Ca(OH)2 is partially converted into CaBr2. DFT calculations provide pathways for the observed surface debromination characterized by surface-assisted fission of aromatic C-Br bonds and the formation of CaBr sites. Outcomes reported herein are instrumental to designing and operating a thermal recycling facility of polymeric materials contaminated with high loads of bromine, i.e., most notably during scenarios encountered in the thermal recycling of e-waste.

Nontarget Identification of Novel Organophosphorus Flame Retardants and Plasticizers in Rainfall Runoffs and Agricultural Soils around a Plastic Recycling Industrial Park.

Plastic recycling and reprocessing activities may release organophosphate ester (OPE) flame retardants and plasticizers into the surrounding environment. However, the relevant contamination profiles and impacts remain not well studied. This study investigated the occurrence of 28 OPEs and their metabolites (mOPEs) in rainfall runoffs and agricultural soils around one of the largest plastic recycling industrial parks in North China and identified novel organophosphorus compounds (NOPs) using high-resolution mass spectrometry-based nontarget analysis. Twenty and twenty-seven OPEs were detected in runoff water and soil samples, with total concentrations of 86.0-2491 ng/L and 2.53-199 ng/g dw, respectively. Thirteen NOPs were identified, of which eight were reported in the environment for the first time, including a chlorine-containing OPE, an organophosphorus heterocycle, a phosphite, three novel OPE metabolites, and two oligomers. Triphenylphosphine oxide and diphenylphosphinic acid occurred ubiquitously in runoffs and soils, with concentrations up to 390 ng/L and 40.2 ng/g dw, respectively. The downwind areas of the industrial park showed elevated levels of OPEs and NOPs. The contribution of hydroxylated mOPEs was higher in soils than in runoffs. These findings suggest that plastic recycling and reprocessing activities are significant sources of OPEs and NOPs and that biotransformation may further increase the ecological and human exposure risk.

Organophosphate esters in rural wastewater along the Yangtze river Basin: Occurrence, removal efficiency and environmental implications.

Organophosphate esters (OPEs) discharged from rural domestic wastewater were one of the important sources of OPEs in receiving water bodies, which has posed a potential threat to the ecological environment. However, very little information on the characteristics of OPEs in the rural domestic wastewater is available. Herein, the occurrence, removal efficiency and environmental implication of OPEs in rural domestic wastewater treatment facilities (RD-WWTFs) along the Yangtze River Basin were investigated. Results indicated that the median concentrations of ΣAlkyl-OPEs, ΣHalogenated-OPEs, ΣAryl-OPEs and the total OPE (ΣOPEs) in influents were 28.28, 99.25, 10.22 and 136.84 ng/L, while the median concentrations of them in effluents were 25.80, 141.86, 7.98 and 173.31 ng/L, respectively. Undoubtedly, halogenated OPEs were the most abundant in both influent and effluent, followed by alkyl and aryl OPEs, and they accounted for average proportions of 69.50%, 19.96%and 10.54% for influents, and 78.16%, 16.14%and 5.71% for effluents, respectively. Specifically, tris(2-chloroisopropyl) phosphate (TCPP, median: 55.17 ng/L in influents and 85.75 ng/L in effluents) was the dominant contributor to the ΣOPEs concentrations with average proportions of 37.75% and 47.33% for influents and effluents, respectively. Moreover, the concentration ranks for most OPEs except for aryl OPEs from high to low were upper reaches > lower reaches > middle reaches. However, negative values of tris(2-chloroethyl)phosphate (TCEP, -32.4%), TCPP (-55.4%) and tris(1,3-dichloroisopropyl) phosphate (TDCPP, -26.3%) were observed. The removal rates of alkyl OPEs (10-20%) and aryl OPEs (20-30%) were also not sufficient. Ecological risk values of ΣOPEs showed that there were 2.44% of high risk, 31.7% of moderate risk and 41.5% of low risk for effluents; while 0.00%, 48.8% and 46.3% were exhibited in high, moderate and low risk for influents, indicating that very slight reduction in risk was achieved by the RD-WWTFs.

Targeted and non-targeted screening of flame retardants in rural and urban honey.

Flame retardants (FRs) are often added to commercial products to achieve flammability resistance, but they are not chemically bonded to the materials, so, they can be easily released into the environment during the production and disposal processes. When honeybees travel to collect nectar during the pollination process, they are prone to be contaminated by chemicals in the air. Therefore, honey contamination has been proposed as an indicator of the pollution status in a particular region. To date, the occurrence of flame retardants in urban honey has yet to be explored. In this study, a direct injection method was used, coupled with LC-QTOF-MS, to analyze honey samples. This method was applied to urban (n = 100) and rural (n = 100) honey samples from the Quebec province (Canada), and the levels of flame retardants in urban and rural honey samples were not significantly different. In the targeted approach, two of the target FRs, tris(2-butoxyethyl) phosphate (TBOEP) and triphenyl phosphate (TPHP), were detected and confirmed at an average trace concentration (<1 ng mL-1). Additionally, a non-targeted screening workflow with an in-house-built library was developed and validated to screen for flame retardants in honey. Tris (2-chloropropyl) phosphate (TCIPP) was identified in honey using the non-targeted screening workflow and confirmed using a pure analytical standard, but there are other compounds detected in the non-targeted analysis that have yet to be validated. This study was the first to report FR compounds based on a direct injection method, coupled with a non-targeted screening workflow, at a trace level in a honey matrix. It also showed that a non-targeted workflow was effective to detect and identify unknown compounds present in the honey sample; hence, this provided a novel angle for the occurrence of FRs in air, with honey as a bio-indicator.

Anti-androgenic activity of novel flame retardants in mixtures: Newly identified contribution from tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO).

In recent decades, male infertility has been on the rise, largely attributed to exposure to chemicals with endocrine-disrupting properties. The adverse effects of disrupting androgen actions on the development and reproductive health of children and adolescents have been extensively studied. Flame retardants (FRs), used in consumer products to delay flammability, have been identified as antagonists of the androgen receptor (AR), potentially leading to adverse outcomes in male reproductive health later in life. This study examined the interaction of eight novel FRs with the AR, employing an in vitro AR-dependent luciferase reporter gene assay utilizing MDA-kb2 cells. The investigation revealed the anti-androgenic activity of tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO), a frequently detected FR in the environment. Furthermore, TDBP-TAZTO contributed to anti-androgenic activity when combined with six other anti-androgenic FRs. The mixture effects were predicted by three commonly employed models: concentration addition (CA), generalized CA, and independent action, with the CA model showcasing the highest accuracy. This suggests that all FRs act through a similar mechanism, as further confirmed by in silico molecular docking, indicating limited synergy or antagonism. Importantly, in the mixtures, each FR contributed to the induction of anti-androgenic effects at concentrations below their individual effective concentrations in single exposures. This raises concern for public health, especially considering the co-detection of these FRs and their potential co-occurrence with other anti-androgenic chemicals like bisphenols. Therefore, our findings, along with previous research, strongly support the incorporation of combined effects of mixtures in risk assessment to efficiently safeguard population health.

Established and emerging organophosphate esters (OPEs) and the expansion of an environmental contamination issue: A review and future directions.

The list of organophosphate esters (OPEs) reported in the environment continues to expand as evidenced by the increasing number of OPE studies in the literature. However, there remains a general dearth of information on more recently produced and used OPEs that are proving to be emerging environmental contaminants. The present review summarizes the available studies in a systematic framework of the current state of knowledge on the analysis, environmental fate, and behavior of emerging OPEs. This review also details future directions to better understand emerging OPEs in the environment. Firstly, we make recommendations that the current structural/practical abbreviations and naming of OPEs be revised and updated. A chemical database (CDB) containing 114 OPEs is presently established based on the suspect list from the current scientific literature. There are 12 established OPEs and a total of 83 emerging OPEs that have been reported in human and/or biota samples. Of the emerging OPEs more than 80% have nearly 100% detection frequencies in samples of certain environmental media including indoor air, wastewater treatment plants, sediment, and fish. In contrast to OPEs considered established contaminants, most emerging OPEs have been identified more recently due to the more pervasive use of high-resolution mass spectrometry (HRMS) based approaches and especially gas or liquid chromatography coupled with HRMS-based non-target analysis (NTA) of environmental sample fractions. Intentional/unintentional industrial use and non-industrial formation are sources of emerging OPEs in the environment. Predicted physical-chemical properties in silico of newer, molecularly larger and more oligomeric OPEs strongly suggest that some compounds such as bisphenol A diphenyl phosphate (BPA-DPP) are highly persistent, bioaccumulative and/or toxic. Limited information on laboratory-based toxicity data has shown that some emerging OPEs elicit harmful effects such as cytotoxicity, development toxicity, hepatotoxicity, and endocrine disruption in exposed humans and mammals. Established, and to a much lesser degree emerging OPEs, have also been shown to transform and degrade in biota and possibly alter their toxicological effects. Research on emerging OPE contaminants is presently limited and more study is warranted on sample analysis methods, source apportionment, transformation processes, environmental behavior, biomarkers of exposure and toxicity.