Scientific Opinion on Emerging and Novel Brominated Flame Retardants (BFRs) in Food

Chemical and genotoxic characterization of bioaccessible fractions as a comprehensive in vitro tool in assessing the health risk due to dust-bound contaminant ingestion

In the last two decades, awareness grew on the matter of the impact of environment on human health. Contaminants sorbed onto soil and settled dust can be ingested and thus represent a hazard, particularly to young children, who play on the ground and bring their hands and objects to their mouth. Metal(loid)s and polycyclic aromatic hydrocarbons (PAHs) are of concern as they are both carcinogenic to humans and ubiquitous in outdoor environments. The present study aims to assess the total and bioaccessible fractions of PAHs and metal(loid)s present in settled dust of four preschools located in industrial, urban, and suburban areas. On the one hand, children's incremental life cancer risks (ILCR) were calculated according to ingestion pathway. On the other hand, the genotoxicities of the bioaccessible dust-bonded contaminants were determined on gastric cells. PAH concentrations ranged from 50.9 to 2267.3 ng/g, and the bioaccessible fraction represented 10.7% of the total in average. Metal(loid) concentration ranged from 12,430 to 38,941 µg/g, and the mean bioaccessibility was of 40.1%. Cancer risk ranged from 2.8.105 to 8.6.105, indicating that there is a potential cancer risk for children linked to the ingestion of settled dust. The inorganic bioaccessible fraction induced little DNA (< 20%TailDNA) and chromosomal damages (30% increase in micronuclei), whereas the organic bioaccessible fraction induced higher DNA (17-63%TailDNA) and chromosomal damages (88% increase in micronuclei). Such experimental approach needs to be deepen, as a tool complementary to cancer risk calculation, since the latter only lays on a set of targeted contaminants with known toxicity values.

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.

Mechanochemical debromination of allyl 2,4,6-tribromophenyl ether (TBP-AE): optimization of the operational conditions

Allyl 2,4,6-tribromophenyl ether (TBP-AE) is a flame retardant that is added to plastics to improve their fire resistance. This kind of additive is hazardous to both human health and the environment. As any other BFRs, TBP-AE resists photo-degradation in the environment and hence materials laden with TBP-AE are to be dibrominated to avoid environmental pollution. Mechanochemical degradation of TBP-AE is a promising approach with potential industrial applications since it does not require high temperatures nor it generates any secondary pollutants. A planetary ball milling simulation experiment was designed to study TBP-AE's mechanochemical debromination. To report products from the mechanochemical process, a variety of characterization techniques were used. The characterization methods included gas chromatography-mass spectrometry (GC-MS), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDX). The effects of various co-milling reagent types, co-milling reagent concentrations with raw material, time, and revolution speed on mechanochemical debromination efficiency have been thoroughly investigated. The Fe/Al2O3 mixture entails the highest debromination efficiency of 23%. However, when using a Fe/Al2O3 mixture, neither the reagent concentration nor the revolution speed influenced the debromination efficiency. In case of using only Al2O3, the next viable reagent, it was revealed that while increasing the revolution, speed improved debromination efficiency to a certain point, and increasing it any further left the debromination efficiency unchanged. In addition, the results showed that an equal mass ratio of TBP-AE to Al2O3 promoted degradation more than an increase in the ratio of Al2O3 to TBP-AE. The addition of ABS polymer largely inhibits the reaction between Al2O3 and TBP-AE, which hindered alumina's ability to capture organic bromine, causing a significant decrease in the debromination efficiency when model of waste printed circuit board (WPCB) is considered.

Validation and Evaluation of Selected Organic Pollutants in Shrimp and Seawater Samples from the NW Portuguese Coast

The development of coastal regions has contributed to the intensification of environmental contamination, which can accumulate in aquatic biota, such as shrimps. These crustaceans, besides being delicious and being a good source of nutrients, can also accumulate environmental pollutants. Amongst others, these include organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs), brominated flame retardants (BFRs), polychlorinated biphenyls (PCBs) and synthetic musks (SMs). These pollutants, classified as endocrine disruptors, are related to adverse effects in humans and since one of the major routes of exposition is ingestion, this is a cause for concern regarding their presence in food. The aim of the present study was to quantify the presence of environmental pollutants in shrimp samples and in the water from their habitat along the northwest Portuguese coast. In seawater samples, only two OCPs (lindane and DDD) and one BFR (BTBPE) were detected, and in shrimp samples, one OCP (DDD) and three SMs (HHCB, AHTN and ketone) were found. Bioaccumulation and the risk assessment of dietary exposure of SMs in shrimp samples were investigated. It was observed that all shrimp samples analyzed significantly presented bioaccumulation of the three SMs found. Concentrations of SMs detected in shrimp samples do not present a health risk for the adult Portuguese population.

Emerging Brominated Flame Retardants 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB) and Bis(2-ethylhexyl)-tetrabromophthalate (BEH-TEBP) in Chinese Food and Their Health Implications

2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (EHTBB) and bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP) have been frequently detected in the environment, whereas studies in food are scare. The European Food Safety Authority has requested data for their risk assessment. Herein, dietary exposure and hazard quotient (HQ) were studied based on the 5th (2009-2012) and 6th (2015-2018) Chinese total diet studies (TDSs). EHTBB was found in 61.1 and 75.9% of the two TDS sample sets, respectively. The concentrations of EHTBB in animal-derived food were higher than those in plant-derived food. The estimated daily intakes (EDIs) were 1.33 and 0.97 ng/kg bw/day, and vegetables contributed to 48.5 and 39.2% of the EDIs based on the 5th and 6th TDS, respectively. The dietary exposure to EHTBB was similar to that to hexabromocyclododecane, brominated diphenyl ether-209, and tetrabromobisphenol A (TBBPA). The HQ for EHTBB was similar to that for decabromodiphenyl ethane and surpassed that for TBBPA. Therefore, EHTBB warrants further study in food.

Recycling Potential for Non-Valorized Plastic Fractions from Electrical and Electronic Waste

This paper describes a study for waste of electrical and electronic equipment (WEEE) to characterise the plastic composition of different mixed plastic fractions. Most of the samples studied are currently excluded from material recycling and arise as side streams in state-of-the-art plastics recycling plants. These samples contain brominated flame retardants (BFR) or other substances of concern listed as persistent organic pollutants or in the RoHS directive. Seventeen samples, including cathode ray tube (CRT) monitors, CRT televisions, flat screens such as liquid crystal displays, small domestic appliances, and information and communication technology, were investigated using density- and dissolution-based separation processes. The total bromine and chlorine contents of the samples were determined by X-ray fluorescence spectroscopy, indicating a substantial concentration of both elements in density fractions above 1.1 g/cm3, most significantly in specific solubility classes referring to ABS and PS. This was further supported by specific flame retardant analysis. It was shown that BFR levels of both polymers can be reduced to levels below 1000 ppm by dissolution and precipitation processes enabling material recycling in compliance with current legislation. As additional target polymers PC and PC-ABS were also recycled by dissolution but did not require an elimination of BFR. Finally, physicochemical investigations of recycled materials as gel permeation chromatography, melt flow rate, and differential scanning calorimetry suggest a high purity and indicate no degradation of the technical properties of the recycled polymers.

Update of the risk assessment of hexabromocyclododecanes (HBCDDs) in food

The European Commission asked EFSA to update its 2011 risk assessment on hexabromocyclododecanes (HBCDDs) in food. HBCDDs, predominantly mixtures of the stereoisomers α-, β- and γ-HBCDD, were widely used additive flame retardants. Concern has been raised because of the occurrence of HBCDDs in the environment, food and in humans. Main targets for toxicity are neurodevelopment, the liver, thyroid hormone homeostasis and the reproductive and immune systems. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour in mice can be considered the critical effects. Based on effects on spontaneous behaviour in mice, the Panel identified a lowest observed adverse effect level (LOAEL) of 0.9 mg/kg body weight (bw) as the Reference Point, corresponding to a body burden of 0.75 mg/kg bw. The chronic intake that would lead to the same body burden in humans was calculated to be 2.35 μg/kg bw per day. The derivation of a health-based guidance value (HBGV) was not considered appropriate. Instead, the margin of exposure (MOE) approach was applied to assess possible health concerns. Over 6,000 analytical results for HBCDDs in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary LB exposure to HBCDDs were fish meat, eggs, livestock meat and poultry. The CONTAM Panel concluded that the resulting MOE values support the conclusion that current dietary exposure to HBCDDs across European countries does not raise a health concern. An exception is breastfed infants with high milk consumption, for which the lowest MOE values may raise a health concern.

Emission of Dioxin-like Compounds and Flame Retardants from Commercial Facilities Handling Deca-BDE and Their Downstream Sewage Treatment Plants

Commercial mixtures of decabromodiphenyl ether (deca-BDE), a brominated flame retardant, contain not only polybrominated diphenyl ethers (PBDEs, mainly BDE-209) as the main component but also dioxin-like compounds (DLCs) such as polybrominated dibenzofurans (PBDFs). Deca-BDE handling facilities (DHFs) and sewage treatment plants receiving effluent from DHFs are point sources of DLC and flame retardant (FR) pollution. Here, we examined their emission in Japan. For DHF effluents, DLCs detected by the dioxin-responsive chemically activated luciferase expression (DR-CALUX) assay were 1.3-890 pg TCDD-EQ/L (median 46 pg TCDD-EQ/L), while PBDEs and other FRs were <2.0-110,000 ng/L (610 ng/L) and 150-4,800,000 ng/L (41,000 ng/L). Risk quotients based on predicted no-effect concentrations suggested that DLCs, decabromodiphenyl ethane (DBDPE), tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO), and bisphenol A bis(diphenyl phosphate) (BPA-BDPP) present significant risks for aquatic organisms. The concentrations of PBDFs, which are impurities in deca-BDE, were expected to decrease with the inclusion of deca-BDE in the Stockholm Convention list of persistent organic pollutants (May 2017). However, DLCs other than PBDFs and alternative FRs such as DBDPE, TDBP-TAZTO, and BPA-BDPP are likely still discharged. Additional findings indicate that strong (e.g., DLCs, DBDPE, and BPA-BDPP), but not weak (e.g., TDBP-TAZTO), hydrophobic compounds are sufficiently removed by current wastewater treatment processes in Japan.

Polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDD), dechlorane-related compounds (DRCs), and emerging brominated flame retardants (EBFRs) in foods: The levels, profiles, and dietary intake in Latvia

This study was performed to assess the Latvian population exposure to polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDD), dechlorane-related compounds (DRCs), and emerging brominated flame retardants (EBFRs). Food items including fish, fish products, meat, dairy products, cereals and bread, eggs, vegetable oils, and sweets were analyzed for the content of these contaminants, followed by per capita intake calculations and risk assessment. The highest dietary exposure for general population was observed in the case of HBCDD, .reaching an estimated daily intake (EDI) value of 2.92 ng kg^-1 b.w. (or 3.35 ng kg^-1 b.w. if an outlying data point is included), followed by PBDEs with EDI of 1.24 ng kg^-1 b.w., including ~25% contribution of PBDE-209 to the overall EDI from PBDEs. DRCs and EBFRs were secondary contributors to the total intake of selected flame retardants (FRs), with the observed EDIs of 0.46 and 0.47 ng kg^-1 b.w, respectively. The obtained occurrence data and risk characterization according to the European Food Safety Authority (EFSA) approach showed the calculated margin of exposure (MOE) values higher than the critical values for PBDE-47, -99 and -153as well as for HBCDD, indicating that the estimated dietary exposures are unlikely to be of significant health concern for the Latvian population. At the same time, it should be pointed out that the risk assessment was performed only for five out of the twenty-five selected halogenated flame retardants (HFRs), while cumulative effects due to the potential presence of other HFRs and their biodegradation products were not considered.

Does arsenic pose a health concern after consumption of clay products?

Clay products for oral use form a particular group of food supplements in relation to potential arsenic (As) toxicity, because - certainly in case of pure clay- all arsenic in these supplements is expected to be present in the most toxic inorganic form (As_i). In terms of risk, the most important questions to answer relate to the bioaccessibility and bioavailability of the inorganic arsenic present, rather than to the As species distribution, which often receives most attention in standard foodstuffs. In the present study, clay products for oral use were bought on the Belgian market and analysed for total arsenic (As_tot), arsenic species (As_i, arsenobetaine, dimethylarsenate and monomethylarsenate)) and bioaccessible arsenic, in order to perform an exposure assessment and risk characterisation. Total As concentrations differed considerably between the samples and ranged from 0.20 to 6.4 mg As_tot/kg. Bioaccessibility of As_i, determined via the Unified Barge Method (extraction making use of digestive enzymes) varied between 8% and 51%. The As_i concentration determined via HPLC-ICP-MS after extraction with diluted HNO₃ + H₂O₂ (as in the CEN method for foodstuffs) was only a poor predictor of the bioaccessible As_i fraction, despite the significant relationship (R² = 0.36; p < .05). The risk characterisation did not reveal acute risks related to As_i exposure. However, a potential concern with regard to chronic As_i intake was identified for the general population in 42% of the analysed food supplements, and for sensitive population groups in 67% of the samples, even after taking into account the bioaccessible fraction. The data presented illustrate that consumption of some of these clay products may contribute significantly to dietary As_i intake and that these should not be taken chronically.

Development and validation of a liquid chromatography-mass spectrometry method for simultaneous analysis of triazine-based brominated flame retardants in environmental samples

In the present study, a novel and reliable analytical method was developed and validated for the simultaneous determination of 1,3,5-tris(2,3-dibromopropyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TDBP-TAZTO) and 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) in environmental samples using high-performance liquid chromatography coupled to a tandem mass spectrometer. Firstly, for optimization of the liquid chromatography separation, mobile phases, oven temperatures, modifiers, and buffers were varied. Afterwards, the extraction efficiency of sediment and fish samples was tested with different techniques (pressurized liquid, solid-liquid, ultrasound-assisted, and Soxhlet extraction). Additionally, cleanup using modified multilayer silica gel (sediment) and gel permeation chromatography as well as Florisil® columns (fish) with several solvent mixtures were performed. The best results were obtained with the pressurized liquid extraction (optimal conditions: extraction solvent 100% toluene, extraction time 20 min, cycles two, extraction temperature 100 °C, and flushing volume 60%) compared to other solvent extraction methods. On the basis of this optimized analytical procedure, the method was validated with satisfactory values of correlation coefficient (R²) between 0.998 and 0.999 for both matrices in the calibration range of 2.0-502.0 μg kg^-1 for TDBP-TAZTO and 16.6-770.6 μg kg^-1 for TTBP-TAZ in sediment samples as well as 4.8-303.5 μg kg^-1 and 47.4-742.5 μg kg^-1 in fish samples (bream), respectively. Mean recoveries (n = 5) were calculated for both analytes with spiked matrices at one concentration level (100 μg kg^-1) between 98 and 114% with intra-day relative standard deviations less than 11%. The inter-day precision (n = 15) was also acceptable for both compounds < 11%. It was found that the limit of detection and limit of quantification were in the range of 0.4-1.3 μg kg^-1 for TDBP-TAZTO and 10-28 μg kg^-1 for TTBP-TAZ in surface sediment samples and 7-25 μg kg^-1 and 22-80 μg kg^-1 in fish samples (bream), respectively. The results indicated that these analytical methods could provide reliable and efficient approaches for quantification of TDBP-TAZTO and TTBP-TAZ in sediment and fish samples. Graphical abstract.

A ranking method of chemical substances in foods for prioritisation of monitoring, based on health risk and knowledge gaps

Chemical contaminants are present in all foods. Data on the occurrence of contaminants in foods that are often consumed or contain high contaminant concentrations are critical for the estimation of exposure and evaluation of potential negative health effects. Due to limited resources for the monitoring of contaminants and other chemical substances in foods, methods for prioritisation are needed. We have developed a straightforward semi-quantitative method to rank chemical substances in foods for monitoring as part of a risk-based food control. The method is based on considerations of toxicity, level of exposure including both occurrence in food and dietary intake, vulnerability of one or more population groups due to high exposure because of special food habits or resulting from specific genetic variants, diseases, drug use or age/life stages, and the adequacy of both toxicity and exposure data. The chemical substances ranked for monitoring were contaminants occurring naturally, unintentionally or incidentally in foods or formed during food processing, and the inclusion criteria were high toxicity, high exposure and/or lack of toxicity or exposure data. In principle, this method can be used for all classes of chemical substances that occur in foods, both unintended contaminants and deliberately added chemical substances. Foods considered relevant for monitoring of the different chemical substances were also identified. The outcomes of ranking exercises using the new method including considerations of vulnerable groups and adequacy of data and a shortened version based on risk considerations only were compared. The results showed that the resolution between the contaminants was notably increased with the extended method, which we considered as advantageous for the ranking of chemical substances for monitoring in foods.

Bioaccumulation characteristics of PBDEs and alternative brominated flame retardants in a wild frog-eating snake

While a large body of studies have examined polybrominated diphenyl ethers (PBDEs) and alternative brominated flame retardants (ABFRs) in wildlife, information on the bioaccumulation of these contaminants in reptiles in general, and snakes in particular, are scarce. We investigated the bioaccumulation characteristics of PBDEs and several ABFRs including decabromodiphenyl ethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB) and pentabromotoluene (PBT) in a frog-eating snake, the striped keelback snake (Amphiesma stolata), from an e-waste recycling site in South China. The concentrations of ∑PBDEs and ∑ABFRs in the snakes ranged 53-5200 and 3.1-87 ng/g lipid weight, respectively; with higher levels in males than females. Additionally, the concentrations of BDE-28, -47, and -66 were positively correlated with snake size (snout-vent length and body mass), while negative correlations were found for most of the higher brominated PBDE congeners and HBB, PBT and BTBPE. The biomagnification factors (BMFs) estimated in the snake/frog relationship indicated a mild to moderate biomagnification of BDE-28, -47, -66, -100, -153 and -154 (with mean BMFs of 1.1-5.3), while a lack of magnification for the other PBDE congeners and all the ABFRs. This is the first report on the sex- and size-related accumulation and biomagnification potentials of PBDEs and ABFRs in snakes.

Multi-analyte method for the analysis of legacy and alternative brominated and chlorinated flame retardants in food products of animal origin using gas chromatography - magnetic sector high resolution mass spectrometry

An analytical method was developed and validated for the analysis of 32 halogenated flame retardants (HFRs), including 13 polybrominated diphenyl ethers (PBDEs), 9 dechlorane-related compounds (DRCs) and 10 of the so-called alternative BFRs in food samples of animal origin. Gas chromatography (GC) coupled with magnetic sector high resolution mass spectrometry (HRMS) was used for the instrumental analysis. Intralaboratory validation of the developed method was performed in terms of recovery, repeatability, linear calibration ranges, instrumental and method limits of quantitation (i-LOQ and m-LOQ). Where possible, trueness was verified by the analysis of reference materials (RMs). For analytes with available isotopically labeled surrogates, recoveries in the range of 70-120% and repeatability rates below 20% were observed, while for compounds quantitated using absolute calibration the values of recovery ranged from 59 to 153% and the repeatability in terms of RSDs was in the range of 1-26%. The values measured for the four analyzed RMs agreed with the provided consensus values, revealing that the recovery of reference concentrations for compounds with assigned consensus values was in 72-119% range. The elaborated method met the sensitivity criteria according to the Commission Recommendation, 2014/118/EU on the monitoring of BFRs in food products. The developed method was successfully applied for the analysis of numerous food samples. The analyses revealed ubiquitous presence of PBDEs and the majority of DRCs in the analyzed samples, while alternative BFRs were detected only occasionally.

Photodegradation of the novel brominated flame retardant 2,4,6-Tris-(2,4,6-tribromophenoxy)-1,3,5-triazine in solvent system: Kinetics, photolysis products and pathway

In this study the direct and indirect photolysis of the novel brominated flame retardant 2,4,6-Tris-(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ) in an organic solvent mixture (60:30:10, ACN:MeOH:THF) under UV-(C) and simulated sunlight irradiation was investigated, and the formed photo-transformation products were identified for the first time. TTBP-TAZ was almost completely degraded within 10 min under UV-(C) irradiation. Due to the fast degradation no specific kinetic order could be observed. In comparison, the reaction under simulated sunlight irradiation was much slower and thus, the kinetic first-order could be determined. The observed photolysis rate constant k as well as the half-life time t_1/2 were estimated to be k = (0.0163 ± 0.0002) h^-1 and t_1/2 = 42.3 h, respectively. The addition of 2-propanol and hydrogen peroxide to investigate the influence of indirect photolysis under UV-(C) irradiation causes no influence on the degradation of TTBP-TAZ. Nevertheless, the removal of TTBP-TAZ under UV-(C) and simulated sunlight without additional chemicals (except solvent) indicates that the direct photolysis plays a significant role in the degradation mechanism of TTBP-TAZ. In both irradiation experiments, TTBP-TAZ was quantitatively degraded that involve the formation of previously unknown PTPs. Overall, two main PTPs were determined when irradiated with UV-(C) and eight sequential debromination products were observed when irradiated by simulated sunlight. These were determined by HPLC-DAD and - MS/(MS), respectively. Based on the chosen experimental conditions the consecutive debromination as well as photo-Fries rearrangement was confirmed as the main degradation pathway by high resolution mass spectrometry and X-ray diffraction.

Occurrence of hexabromocyclododecanes and tetrabromobisphenol A in fish and seafood from the sea of Sardinia - FAO 37.1.3 area: Their impact on human health within the European Union marine framework strategy directive

Levels of hexabromocyclododecane isomers α, β, γ, (HBCDDs) and tetrabromobisphenol A (TBBP-A) were determined in 24 representative samples of different wild fish and seafood species (benthic: N = 16; pelagic: N = 8) and 16 samples of farmed bivalve molluscs from the West Mediterranean Sea (FAO 37, 1.3 sub-area). An LC-MS/MS-based method with limits of quantification (LOQS) in the range of 0.01-0.05 ng g^-1 fresh weight (fw) was utilized. While α HBCDD was found in 80% of the 24 wild species samples, β and γ congeners were found in 33% and 25%, respectively. ΣHBCDD content ranged from 0.03 (Aristeus antennatus) to 0.68 (Sardina pilchardus) ng g^-1 fw as Upper Bound values across 2.00-4.46 trophic levels. In farmed molluscs, HBCDD congeners were always present and ranged from 0.22-0.52 ng g^-1 fw, with the exception of one farm (1.23-2.06 ng g^-1 fw), whose values suggest the presence of a regular emission source. TBBP-A levels always fell below the LOQ of 0.05 ng g^-1 fw in all samples. The results are in good agreement with results of previous studies from the Mediterranean Sea. The Environmental Quality Standard for human health from fish and seafood local consumption was set at 165 μg g^-1 fw. The Margin of Exposure of 490,020 as the ratio between the considered Health Based Guidance Level of 0.79 mg kg^-1 body weight and the geo-referenced HBCDD intake (P95 fish and seafood intake; mean ΣHBCDD contamination) indicates no threat to food safety.

Halogenated flame retardants and organophosphate esters in the air of electronic waste recycling facilities: Evidence of high concentrations and multiple exposures

BACKGROUND

In response to a worldwide increase in production of electronic waste, the e-recycling industry is rapidly rowing. E-recycling workers are exposed to many potentially toxic contaminants, among which flame retardants (FRs), mainly suspected of being endocrine disruptors, are thought to be the most prevalent.

OBJECTIVE

To conduct an exposure assessment of four chemical groups of FRs in Canadian e-recycling facilities, and to identify the main cofactors of exposure.

METHODS

Personal air samples were collected over a workday for 85 workers in six e-recycling facilities, grouped into three facility sizes, and for 15 workers in control commercial waste facilities. Total particulate matter was measured by gravimetry with stationary air samples. FRs were collected on OSHA versatile samplers, which allow particulate and vapor phases collection. Fifteen polybrominated diphenyl ether congeners (PBDEs), nine novel brominated (NBFRs), two chlorinated (ClFRs), and fourteen organophosphate ester (OPEs) flame retardants were analysed by gas chromatography-mass spectrometry. Sociodemographic data, tasks performed and materials processed by participating workers were recorded. Tobit regressions were used to identify cofactors of exposure, and their conclusions were corroborated using semi-parametric reverse Cox regressions.

RESULTS

Thirty-nine of the 40 FRs analysed were detected in at least one air sample in e-recycling, and workers in this industry were exposed on average to 26 (range 12 to 39) different substances. The most detected chemical group of FRs in e-recycling was PBDEs with geometric mean sums of all congeners ranging from 120 to 5100 ng/m³, followed by OPEs with 740 to 1000 ng/m³, NBFRs with 7.6 to 100 ng/m³, and finally ClFRs with 3.9 to 32 mg/m³. The most important cofactor of exposure was the size of the e-recycling facility, with the largest one presenting on average 12 times the concentrations found in the control facility. Among tasks as potential cofactors of exposure, manual dismantling and baler operation exposed workers to some of the highest concentrations of PBDEs and ClFRs. There was a reduction of up to 27% in exposure to FRs associated with a 3-year increase in seniority. Finally, particulate matter concentrations in e-recycling facilities were highly correlated with all chemical classes except OPEs, and were higher in the large facility.

CONCLUSIONS

Among the FRs analysed, PBDE exposure was particularly high in e-recycling. Dust and particulate matter reduction strategies in these workplaces, together with training on proper working practices would certainly be important first steps to lower occupational exposures and prevent potential health effects.

1,3,5-Tris-(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione: kinetic studies and phototransformation products

1,3,5-Tris-(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione (TDBP-TAZTO) is an emerging brominated flame retardant which is widely used in several plastic materials (electric and electronic equipment, musical instruments, automotive components). However, until today, no photochemical studies as well as the identification of possible phototransformation products (PTPs) were described in literature. Therefore, in this study, UV-(C) and simulated sunlight irradiation experiments were performed to investigate the photolytic degradation of TDBP-TAZTO and to identify relevant PTPs for the first time. The UV-(C) irradiation experiments show that the photolysis reaction follows a first-order kinetic model. Based on this, the photolysis rate constant k as well as the half-life time t_1/2 were calculated to be k = (41 ± 5 × 10^-3) min^-1 and t_1/2 = (17 ± 2) min. In comparison, a minor degradation of TDBP-TAZTO and no formed phototransformation products were obtained under simulated sunlight. In order to clarify the photochemical behavior, different chemicals were added to investigate the influence on indirect photolysis: (i) H₂O₂ for generation of hydroxyl radicals and (ii) two quenchers (2-propanol, sodium azide) for scavenging oxygen species which were formed during the irradiation experiments. Herein, nine previously unknown PTPs of TDBP-TAZTO were detected under UV-(C) irradiation and identified by HPLC-(HR)MS. As a result, debromination, hydroxylation, and dehydrobromination reactions could be presumed as the main degradation pathways by high-resolution mass spectrometry. The direct as well as the OH radical-induced indirect photolysis were observed. Graphical abstract .

Biomagnification of PBDEs and alternative brominated flame retardants in a predatory fish: Using fatty acid signature as a primer

Information on biomagnification of alternative brominated flame retardants (ABFRs) is limited and results are inconclusive, due in part to uncertainty in the understanding of predator/prey relationships. In the present study, a predatory fish, Channa argus, and several forage fish species were obtained from an ABFR contaminated site. The predator/prey relationships were identified based on fatty acid (FA) signatures in the predator and prey. Biomagnification factors (BMFs) for several ABFRs including decabromodiphenyl ethane (DBDPE), 1,2‑bis(2,4,6‑tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), pentabromotoluene (PBT), and pentabromoethylbenzene (PBEB) were estimated based on the identified predator/prey relationships. The results showed that crucian carp was the main prey of C. argus, contributing to 71%-100% to its total diet. The mean BMFs for DBDPE, BTBPE, and HBB were 0.06, 0.40, and 0.91, respectively, indicating trophic dilution of these ABFRs. However, biomagnification of PBT and PBEB, with BMFs of 2.09 and 2.13, respectively, was observed. The BMFs for PBT, PBEB and HBB were comparable to or even higher than those for some polybrominated diphenyl ether (PBDE) congeners estimated in the same individual predator, indicating that these emerging pollutants may pose significant environmental risks. The BMFs for ABFRs and PBDEs were significantly and negatively correlated to the log K_OWs of these chemicals, suggesting that the biomagnification of these chemicals was depressed due to their superhydrophobic nature.

Towards a dietary-exposome assessment of chemicals in food: An update on the chronic health risks for the European consumer

An informed opinion to a hugely important question, whether the food on the Europeans' plate is safe to eat, is provided. Today, the Europeans face food-borne health risks from non-communicable diseases induced by excess body weight, outbreaks caused by pathogens, antimicrobial resistance and exposures to chemical contaminants. In this review, these risks are first put in an order of importance. Then, not only potentially injurious dietary chemicals are discussed but also beneficial factors of the food. This review can be regarded as an attempt towards a dietary-exposome evaluation of the chemicals, the average European adult consumers could chronically expose to during their life-times. Risk ranking reveals that currently the European adults are chronically exposed to a mixture of potentially genotoxic-carcinogenic contaminants, particularly food process contaminants, at the potential risk levels. Furthermore, several of the contaminants whose dietary exposures pose risks appear to be carcinogens operating with a genotoxic mode of action targeting the liver. This suggests that combined health risks from the exposure to a mixture of the chemical contaminants poses a greater potential risk than the risks assessed for single compounds. Over 100 European-level risk assessments are examined. Finally, the importance of a diversified and balanced diet is emphasized.

Novel brominated flame retardant (NBFR) concentrations and spatial distributions in global fishmeal

Novel brominated flame retardants (NBFRs), which are lipophilic compounds that have been widely applied after the phasing-out of legacy BFRs, can bioaccumulate through the food chain. However, information on NBFRs in animal feeds, the beginning of farm-to-fork pathway, is very limited. Fishmeal is one of the most widely applied feedstuff worldwide. The present study identified eleven NBFRs from ninety-two globally collected fishmeal samples with levels in the range of 0.13-822 (mean: 15.1 ± 85.5) ng/g lipid weight (lw). Hexabromobenzene (HBB) and pentabromotoluene (PBT) were the most prevalent contributors (detection frequencies: 95.7% and 73.9%, respectively), and decabromodiphenylethane (DBDPE) was the weightiest contributor (accounted for 67.1% of the ΣNBFRs, mean: 12.1 ± 84.8 ng/g lw). From a geographical view, the highest NBFR level was found in Chinese fishmeal. The NBFRs fell within an order of magnitude in South America, Southeast Asia, Europe and United States. DBDPE was predominant in the fishmeal collected from China, South America and United States, but it was not detected in European fishmeal. The NBFR levels are significantly lower compared to the polybrominated diphenyl ethers (PBDEs) (p < 0.01), indicating that the distribution of NBFRs was not as wide as PBDEs in fishmeal. DBDPE was significantly correlated with BDE209 (r = 0.557, p < 0.01), which implies that the two chemicals might have similar sources. Quantitative structure-activity relationship (QSAR)results imply that the NBFRs might have similar persistence and biomagnification potential as legacy lipophilic POPs.

Environmental ototoxicants, a potential new class of chemical stressors

Hearing loss is an injury that can develop over time, and people may not even be aware of it until it becomes a severe disability. Ototoxicants are substances that may damage the inner ear by either affecting the structures in the ear itself or by affecting the nervous system. We have examined the possibility that ototoxicants may present a health hazard in association with environmental exposures, adding to existing knowledge of their proven hazards under medical therapeutic conditions or occupational activities. In addition to the already described human environmental ototoxicants, mainly organochlorines such as polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), hexachlorocyclohexane (HCH) and hexachlorobenzene (HCB), we have examined the ubiquitous chemical stressors phthalates, bisphenol A/S/F/, PFCs, flame retardants (FRs) and cadmium for potential ototoxic properties, both as single substances or as chemical mixtures. Our literature review confirmed that these chemicals may disturb thyroid hormones homeostasis, activate aryl hydrocarbon receptor (AhR), and induce oxidative stress, which in turn may initiate a chain of events resulting in impairment of cochlea and hearing loss. With regard to auditory plasticity, diagnostics of a mixture of effects of ototoxicants, potential interactions of chemical and physical agents with effects on hearing, parallel deterioration of hearing due to chemical exposures and ageing, metabolic diseases or obesity, even using specific methods as brainstem auditory evoked potentials (BAEP) or otoacoustic emissions (OAEs) registration, may be difficult, and establishment of concentration-response relationships problematic. This paper suggests the establishment of a class of environmental oxotoxicants next to the established classes of occupational and drug ototoxicants. This will help to properly manage risks associated with human exposure to chemical stressors with ototoxic properties and adequate regulatory measures.

Transformation Products of Organic Contaminants and Residues-Overview of Current Simulation Methods

The formation of transformation products (TPs) from contaminants and residues is becoming an increasing focus of scientific community. All organic compounds can form different TPs, thus demonstrating the complexity and interdisciplinarity of this topic. The properties of TPs could stand in relation to the unchanged substance or be more harmful and persistent. To get important information about the generated TPs, methods are needed to simulate natural and manmade transformation processes. Current tools are based on metabolism studies, photochemical methods, electrochemical methods, and Fenton’s reagent. Finally, most transformation processes are based on redox reactions. This review aims to compare these methods for structurally different compounds. The groups of pesticides, pharmaceuticals, brominated flame retardants, and mycotoxins were selected as important residues/contaminants relating to their worldwide occurrence and impact to health, food, and environmental safety issues. Thus, there is an increasing need for investigation of transformation processes and identification of TPs by fast and reliable methods.

Occurence of legacy and novel brominated flame retardants in food and feed in France for the period 2014 to 2016

Determination of the occurrence levels of legacy and novel BFRs is today required to better understand the trends of BFRs contamination in food consecutive to the EU PBDEs restrictions and to proceed to a recent human food exposure in parallel. Therefore, concentrations of a large set of brominated flame retardants (BFRs) (n = 27) including PBDEs, HBCDDs, TBBPA and novel flame retardants (nBFRs) have been determined in more than 600 food and feed samples collected between 2014 and 2016 in the context of French monitoring plans. Although legacy BFRs had already been studied in France, such a survey constituted the very first determination of nBFRs occurrence in foodstuffs at the national level. The concentration levels measured in fish and fish products were in general higher than in the other food categories. PBDEs were detected in 70% of the samples and were observed as the most abundant congeners (representing 80% of the sum of the monitored BFRs), while α-HBCDD could also be considered as a predominant congener (up to 26% of the sum of the monitored BFRs in fishes). nBFRs concentration levels were most of the time below the LOQ, except PBT, PBBz and HBBz which were more frequently detected at low levels. Also investigated in the study, BRPs exhibited high concentration levels in crustaceous (maximum value > 2700 pg/g ww).

Brominated Flame Retardants and Organophosphate Esters in Preschool Dust and Children's Hand Wipes

Children spend a considerable part of their day in preschool, where they may be exposed to hazardous chemicals in indoor dust. In this study, brominated flame retardants (BFRs) and organophosphate esters (OPEs) were analyzed in preschool dust ( n = 100) and children's hand wipe samples ( n = 100), and diphenyl phosphate (DPHP) was analyzed in urine ( n = 113). Here we assessed children's exposure via dust, identified predictors for chemicals in dust, and studied correlations between different exposure measures. The most abundant BFRs in dust were decabromodiphenyl ether (BDE-209) and decabromodiphenyl ethane (DBDPE) found at median levels of 270 and 110 ng/g dust, respectively. Tris(2-butoxyethyl) phosphate (TBOEP) was the most abundant OPE, found at a median level of 79 000 ng/g dust. For all OPEs and some BFRs, there were significant correlations between the levels in dust and hand wipes. In addition, triphenyl phosphate (TPHP) in preschool dust was significantly correlated with the corresponding metabolite DPHP in children's urine. The levels of pentaBDEs in dust were higher in older preschools compared with newer, whereas levels of DBDPE were higher in newer preschools. Children's estimated intakes of individual BFRs and OPEs via preschool dust were below available health-based reference values. However, there are uncertainties about the potential health effects of some emerging BFRs and OPEs.

Occurrence of polybrominated diphenylethers, hexabromocyclododecanes, bromophenols and tetrabromobisphenols A and S in Irish foods

The occurrence of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), tetrabromobisphenol A (TBBPA) and other phenolic brominated flame retardants (BFRs) in Irish foodstuffs has been assessed. A total of 53 food samples including eggs, milk, fish, fat and offal were tested. Eighty-one percent of the samples contained at least one measurable PBDE congener. The most abundant and frequently occurring congeners were BDE-47, BDE-49, BDE-99, BDE-100 and BDE-209 with the highest concentrations found in fish, fat and eggs. Summed concentrations for the measured PBDEs ranged from 0.02 μg/kg to 1.37 μg/kg whole weight. At least one HBCD stereoisomer was found in twenty-six percent of the samples with α-HBCD being the most frequently detected. The highest concentrations were found in fat and oily fish samples. TBBPA was only detected in one farmed salmon sample at 0.01 μg/kg. Bromophenol residues were found in fourteen out of the 53 samples, specifically in eggs and fish, with concentrations ranging from 0.28 to 0.98 μg/kg whole weight. These data contribute to the EU-wide EFSA risk assessment on these contaminants that is currently underway.

Emerging brominated flame retardants and dechlorane-related compounds in European eels (Anguilla anguilla) from Latvian lakes

Fifteen halogenated flame retardants (HFRs) including seven emerging brominated flame retardants (EBFRs) and eight dechlorane-related compounds (DRCs) were analyzed in eels (Anguilla anguilla) sampled from five Latvian lakes. Out of the seven EBFRs, hexabromocyclododecane (HBCD) and decabromodiphenyl ethane (DBDPE) were found in eels in quantifiable concentrations, up to 6.58 and 33.0 ng g^-1 lipid weight (l.w.), respectively. The mean total concentration of DRCs (∑_DRC) in the samples was 0.62 ng g^-1 l.w. and the geographical distribution of DRC contamination was nearly uniform among the selected lakes. Dechlorane 602 (Dec 602) was the predominant component, whereas the composition of mixture containing syn- and anti-Dechlorane Plus (DP) stereoisomers showed a pronounced enrichment of the anti-DP isomer and was close to the composition of OxyChem^® DP commercial product. The determined concentrations of HFRs were lower than in other studies of aquatic biota from Europe and Asia, and the obtained results reflect the acceptable environmental status of Latvian lakes with regard to the total content of HBCD (∑_HBCD), considering the environmental quality standards (EQS) stated in the Directive 2013/39/EU. The highest ∑_HBCD levels were observed in eels from lakes corresponding to the industrialization of those areas, while the results of principal component analysis (PCA) showed that the concentration of HBCD depended on the particular sampling lake, reflecting non-uniform contamination of the Latvian environment with this EBFR.

Alternative Flame Retardant, 2,4,6-Tris(2,4,6-tribromophenoxy)-1,3,5-triazine, in an E-waste Recycling Facility and House Dust in North America

A high molecular weight compound, 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ), was detected during the analysis of brominated flame retardants in dust samples collected from an electrical and electronic waste (e-waste) recycling facility in Ontario, Canada. Gas chromatography coupled with both high-resolution and low-resolution mass spectrometry (MS) was used to determine TTBP-TAZ's chemical structure and concentrations. To date, TTBP-TAZ has only been detected in plastic casings of electrical and electronic equipment and house dust from The Netherlands. Here we report on the concentrations of TTBP-TAZ in selected samples from North America: e-waste dust ( n = 7) and air ( n = 4), residential dust ( n = 30), and selected outdoor air ( n = 146), precipitation ( n = 19), sediment ( n = 11) and water ( n = 2) samples from the Great Lakes environment. TTBP-TAZ was detected in all the e-waste dust and air samples, and in 70% of residential dust samples. The median concentrations of TTBP-TAZ in these three types of samples were 5540 ng/g, 5.75 ng/m³ and 6.76 ng/g, respectively. The flame retardants 2,4,6-tribromophenol, tris(2,3-dibromopropyl) isocyanurate, and 3,3',5,5'-tetrabromobisphenol A bis(2,3-dibromopropyl) ether, BDE-47 and BDE-209 were also measured for comparison. None of these other flame retardants concentrations was significantly correlated with those of TTBP-TAZ in any of the sample types suggesting different sources. TTBP-TAZ was not detected in any of the outdoor environmental samples, which may relate to its application history and physicochemical properties. This is the first report of TTBP-TAZ in North America.

Assessing the effects of seawater temperature and pH on the bioaccumulation of emerging chemical contaminants in marine bivalves

Emerging chemical contaminants [e.g. toxic metals speciation, flame retardants (FRs) and perfluorinated compounds (PFCs), among others], that have not been historically recognized as pollutants nor their toxicological hazards, are increasingly more present in the marine environment. Furthermore, the effects of environmental conditions (e.g. temperature and pH) on bioaccumulation and elimination mechanisms of these emerging contaminants in marine biota have been poorly studied until now. In this context, the aim of this study was to assess, for the first time, the effect of warmer seawater temperatures (Δ = + 4°C) and lower pH levels (Δ = - 0.4 pH units), acting alone or combined, on the bioaccumulation and elimination of emerging FRs (dechloranes 602, 603 and 604, and TBBPA), inorganic arsenic (iAs), and PFCs (PFOA and PFOS) in two estuarine bivalve species (Mytilus galloprovincialis and Ruditapes philippinarum). Overall, results showed that warming alone or combined with acidification promoted the bioaccumulation of some compounds (i.e. dechloranes 602, 604, TBBPA), but also facilitated the elimination of others (i.e. iAs, TBBPA). Similarly, lower pH also resulted in higher levels of dechloranes, as well as enhanced iAs, PFOA and PFOS elimination. Data also suggests that, when both abiotic stressors are combined, bivalves' capacity to accumulate contaminants may be time-dependent, considering significantly drastic increase observed with Dec 602 and TBBPA, during the last 10 days of exposure, when compared to reference conditions. Such changes in contaminants' bioaccumulation/elimination patterns also suggest a potential increase of human health risks of some compounds, if the climate continues changing as forecasted. Therefore, this first study pointed out the urgent need for further research on the effects of abiotic conditions on emerging contaminants kinetics, to adequately estimate the potential toxicological hazards associated to these compounds and develop recommendations/regulations for their presence in seafood, considering the prevailing environmental conditions expected in tomorrow's ocean.

Bioaccumulation of persistent and emerging pollutants in wild sea urchin Paracentrotus lividus

Marine pollution has been increasing as a consequence of anthropogenic activities. The preservation of marine ecosystems, as well as the safety of harvested seafood, are nowadays a global concern. Here, we report for the first time the contamination levels of a large set of 99 emerging and persistent organic contaminants (butyltins (BTs), polycyclic aromatic hydrocarbons (PAHs), pesticides including pyrethroids, pharmaceuticals and personal care products (PCPs) and flame retardants) in roe/gonads of sea urchin Paracentrotus lividus. Sea urchins are a highly prized worldwide delicacy, and the harvesting of this seafood has increased over the last decades, particularly in South West Atlantic coast, where this organism is harvested mainly for exportation. Sampling was performed in three harvesting sites of the NW Portuguese coast subjected to distinct anthropogenic pressures: Carreço, Praia Norte and Vila Chã, with sea urchins being collected in the north and south areas of each site. Butyltins and pharmaceuticals were not found at measurable levels. Several PAHs, four pyrethroids insecticides, four PCPs and eleven flame retardants were found in roe/gonads of sea urchins, though in general at low levels. Differences among harvesting sites and between areas within each site were found, the lowest levels of contaminants being registered in Carreço. The accumulation of contaminants in sea urchins' roe/gonads seemed to reflect the low anthropogenic pressure felt in the sampling sites. Nevertheless, taking into account the low accumulated levels of chemicals, results indicate that sea urchins collected in South West Atlantic coast are safe for human consumption.

Oxidation reactivity of 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) by Compound I model of cytochrome P450s

Alternative brominated flame retardants (BFRs) have become prevalent as a consequence of restrictions on the use of polybrominated diphenyl ethers (PBDEs). For risk assessment of these alternatives, knowledge of their metabolism via cytochrome P450 enzymes is needed. We have previously proved that density functional theory (DFT) is able to predict the metabolism of PBDEs by revealing the molecular mechanisms. In the current study, the reactivity of 1,2-bis(2,4,6-tribromophenoxy)ethane and structurally similar chemicals with the Compound I model representing the active site of P450 enzymes was investigated. The DFT calculations delineated reaction pathways which lead to reasonable explanations for products that were detected by wet experiments, meanwhile intermediates which cannot be determined were also proposed. Results showed that alkyl hydrogen abstraction will lead to bis(2,4,6-tribromophenoxy)ethanol, which may undergo hydrolysis yielding 2,4,6-tribromophenol, a neurotoxic compound. In addition, a general pattern of oxidation reactivity regarding the 2,4,6-tribromophenyl moiety was observed among several model compounds. Our study has provided insights for convenient evaluation of the metabolism of other structurally similar BFRs.

Parallel in vivo and in vitro transcriptomics analysis reveals calcium and zinc signalling in the brain as sensitive targets of HBCD neurotoxicity

Hexabromocyclododecane (HBCD) is a brominated flame retardant (BFR) that accumulates in humans and affects the nervous system. To elucidate the mechanisms of HBCD neurotoxicity, we used transcriptomic profiling in brains of female mice exposed through their diet to HBCD (199 mg/kg body weight per day) for 28 days and compared with those of neuronal N2A and NSC-19 cell lines exposed to 1 or 2 µM HBCD. Similar pathways and functions were affected both in vivo and in vitro, including Ca²⁺ and Zn²⁺ signalling, glutamatergic neuron activity, apoptosis, and oxidative stress. Release of cytosolic free Zn²⁺ by HBCD was confirmed in N2A cells. This Zn²⁺ release was partially quenched by the antioxidant N-acetyl cysteine indicating that, in accordance with transcriptomic analysis, free radical formation is involved in HBCD toxicity. To investigate the effects of HBCD in excitable cells, we isolated mouse hippocampal neurons and monitored Ca²⁺ signalling triggered by extracellular glutamate or zinc, which are co-released pre-synaptically to trigger postsynaptic signalling. In control cells application of zinc or glutamate triggered a rapid rise of intracellular [Ca²⁺]. Treatment of the cultures with 1 µM of HBCD was sufficient to reduce the glutamate-dependent Ca²⁺ signal by 50%. The effect of HBCD on zinc-dependent Ca²⁺ signalling was even more pronounced, resulting in the reduction of the Ca²⁺ signal with 86% inhibition at 1 µM HBCD. Our results show that low concentrations of HBCD affect neural signalling in mouse brain acting through dysregulation of Ca²⁺ and Zn²⁺ homeostasis.

Changes in Flame Retardant and Legacy Contaminant Concentrations in Indoor Air during Building Construction, Furnishing, and Use

A newly constructed university building was selected for targeted assessment of changes in the levels of flame retardants and legacy contaminants during the installation of building equipment, furniture, electronics, and first year of building use. Indoor air samples were collected during several periods of intensive equipment installation to determine a relationship between newly introduced equipment and changes in the concentrations and profiles of contaminants in indoor air. Samples were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), and new types of flame retardants: brominated (BFRs) and organophosphate esters (OPEs). Additionally, typical outdoor contaminants such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were also analyzed for comparison. From the set of 90 compounds analyzed here, hexabromobenzene (HBB) and tris(2-chloroisopropyl)phosphate (TCIPP) showed a significant concentration increase in indoor air concentrations during computer installation and operation, suggesting emission by operating computers, while an order of magnitude concentration increase in tris(1,3-dichloro-2-propyl)phosphate (TDCIPP) and tri-m-cresyl phosphate (TMTP) was observed after the furniture and carpet was introduced to the computer room, suggesting furniture or carpet as a source. However, the majority of compounds had no systematic change in concentrations during equipment installation, indicating that no sources of target compounds were introduced or, that source introduction was not reflected in indoor air concentrations. Generally, low levels of legacy flame retardants compared to their novel alternatives were observed.

Atmospheric Pressure Chemical Ionization Gas Chromatography Mass Spectrometry for the Analysis of Selected Emerging Brominated Flame Retardants in Foods

Emerging brominated flame retardants (eBFRs) other than polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and their derivatives in foods have been in focus in recent years due to their increasing production volumes, indefinite information on toxicities and the lack of data on occurrence in environments, foods as well as humans. In this study, gas chromatography was coupled to an atmospheric pressure chemical ionization-tandem mass spectrometry (APGC-MS/MS) for the analysis of six eBFRs in pork, chicken, egg, milk and fish. A short section of unpacked capillary column coupled to the end of the analytical column was applied to improve the chromatographic behaviors of high boiling point compounds. The method was comprehensively validated with method limit of quantification (mLOQ) lower than 8 pg/g wet weight (w.w.). Samples from Chinese Total Diet study were quantified following the validated APGC-MS/MS method. 2,3,4,5-pentabromo-6-ethylbenzene (PBEB), hexabromobenzene (HBB), pentabromotoluene (PBT) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) were most frequently detected in samples. The highest concentration was found in fish with 351.9 pg/g w.w. of PBT. This is the first report on the presence of PBT in food samples with non-ignorable concentrations and detection rate.

Cats' Internal Exposure to Selected Brominated Flame Retardants and Organochlorines Correlated to House Dust and Cat Food

Pet cats may be used as a biomarker for assessing exposures to organohalogen compounds (OHCs) adsorbed to household dust in home environments. This study explores two exposure routes of OHCs, ingestion of OHCs (i) via house dust and (ii) via cat food. House dust from 17 Swedish homes and serum from the participating families' pet cats were collected, and cat food was purchased matching the diet reported. Paired samples of cat serum, house dust, and cat food were analyzed for brominated flame retardants/natural products (polybrominated diphenyl ethers (PBDEs), decabromobiphenyl (BB-209), decabromodiphenyl ethane (DBDPE), 2,4,6-tribromophenol (2,4,6-TBP), OH-PBDEs) and organochlorines (polychlorinated biphenyls (PCBs), 1,1-bis(4,4'-dichlorodiphenyl)-2,2,2-trichloroethane (4,4'-DDT), 1,1-bis(4,4'-dichlorodiphenyl)-2,2-dichloroethene (4,4'-DDE), hexachlorobenzene (HCB), pentachlorophenol (PCP)). Significant correlations were found between serum and dust samples from the living rooms for BDE-47 (p < 0.035), BDE-99 (p < 0.035), and BDE-153 (p < 0.039), from the adult's bedroom for BDE-99 (p < 0.019) and from all rooms for BDE-99 (p < 0.020) and BB-209 (p < 0.048). This is the first time a correlation between cat serum levels and household dust has been established, a finding that supports the hypothesis that dust is a significant exposure route for cats. Serum levels were also significantly correlated with concentrations found in cat food for 6-OH-BDE47 (p < 0.002), 2,4,6-TBP (p < 0.035), and BB-209 (p < 0.007). DBDPE was found in high concentrations in all dust (median 154 pmol/g) and food samples (median 0.7 pmol/g lw) but was below detection in serum samples, suggesting low or no bioavailability for DBDPE in cats.

APCI as an innovative ionization mode compared with EI and CI for the analysis of a large range of organophosphate esters using GC-MS/MS

Organophosphate esters (OPEs) are chemical compounds incorporated into materials as flame-proof and/or plasticizing agents. In this work, 13 non-halogenated and 5 halogenated OPEs were studied. Their mass spectra were interpreted and compared in terms of fragmentation patterns and dominant ions via various ionization techniques [electron ionization (EI) and chemical ionization (CI) under vacuum and corona discharge atmospheric pressure chemical ionization (APCI)] on gas chromatography coupled to mass spectrometry (GC-MS). The novelty of this paper relies on the investigation of APCI technique for the analysis of OPEs via favored protonation mechanism, where the mass spectra were mostly dominated by the quasi-molecular ion [M + H]⁺ . The EI mass spectra were dominated by ions such as [H₄ PO₄ ]⁺ , [M-R]⁺ , [M-Cl]⁺ , and [M-Br]⁺ , and for some non-halogenated aryl OPEs, [M]^+● was also observed. The CI mass spectra in positive mode were dominated by [M + H]⁺ and sometimes by [M-R]⁺ , while in negative mode, [M-R]^- and more particularly [X]^- and [X₂ ]^-● were mainly observed for the halogenated OPEs. Both EI and APCI techniques showed promising results for further development of instrumental method operating in selective reaction monitoring mode. Instrumental detection limits by using APCI mode were 2.5 to 25 times lower than using EI mode for the non-brominated OPEs, while they were determined at 50-100 times lower by the APCI mode than by the EI mode, for the two brominated OPEs. The method was applied to fish samples, and monitored transitions by using APCI mode showed higher specificity but lower stability compared with EI mode. The sensitivity in terms of signal-to-noise ratio varying from one compound to another. Copyright © 2016 John Wiley & Sons, Ltd.

Emerging and Legacy Flame Retardants in UK Indoor Air and Dust: Evidence for Replacement of PBDEs by Emerging Flame Retardants?

Concentrations of 27 emerging (EFRs) and legacy flame retardants (LFRs) were measured in samples of indoor air (n = 35) and indoor dust (n = 77) from UK homes and offices. All target compounds were detected in indoor air and dust samples. Relatively volatile EFRs (e.g., tetrabromoethylcyclohexane-DBE-DBCH) were more frequently detected in indoor air (detection frequencies >60%), while less volatile EFRs (e.g., tetrabromobisphenolA-bis(2,3-dibromopropyl ether (TBBPA-BDBPE) and decabromodiphenyl ethane (DBDPE)) were predominant in dust. Concentrations of some EFRs (e.g., DBDPE) exceeded significantly those reported previously in UK dust (p < 0.05), while concentrations of BDE-209 in office dust were significantly lower (p < 0.05) than those reported previously in UK offices, consistent with the application of DBDPE as an alternative to the Deca-BDE formulation, of which BDE-209 is the principal constituent. Moreover, concentrations of BDEs-47 and -99 (both major constituents of the Penta-BDE product) in office air were significantly lower (p < 0.05) than those in previous UK studies. Our results constitute important early evidence that restrictions on PBDEs have increased demand for EFRs in the UK, with the result that human exposure to PBDEs in UK homes and offices has decreased while exposure to EFRs has risen.

Distribution pattern of legacy and "novel" brominated flame retardants in different particle size fractions of indoor dust in Birmingham, United Kingdom

This study investigates the particle size distribution of eight polybrominated diphenyl ethers (PBDEs) and five "novel" brominated flame retardants (NBFRs) in settled house dust. Elevated surface dust (ESD) and floor dust (FD) were collected from 5 homes in Birmingham, UK, yielding a total of 10 samples. Each sample was fractionated into three different particle sizes: 125-250 μm (P1), 63-125 μm (P2) and 25-63 μm (P3). Non-fractionated bulk dust samples (BD) were also analysed. BDE-209 predominated, comprising an average 74.3%, 77.3%, 69.2%, and 62.7% ΣBFRs of BD, P1, P2 and P3 respectively. Σ5NBFRs contributed 24.2%, 21.5%, 29.0% and 35.3% ΣBFRs, while Σ7tri-hepta-BDEs represented 1.5%, 1.2%, 1.7%, and 2.0% ΣBFRs. BEH-TEBP was the predominant NBFR contributing 76.9%, 75.1%, 83.1%, and 83.9% ΣNBFRs in BD, P1, P2 and P3 respectively; followed by DBDPE which contributed 20.1%, 21.9%, 14.1% and 13.9% ΣNBFRs. EH-TBB, BTBPE and PBEB were the least abundant NBFRs. Concentrations of Σ7tri-hepta-BDEs and BEH-TEBP in P3 exceeded significantly (P < 0.05) those in P2, with those in P2 exceeding significantly those in P1. In contrast, no significant differences were found between concentrations of BDE-209, EH-TBB, BTBPE, and DBDPE in different particle size fractions. Concentrations of Σ7tri-hepta-BDEs, BDE-209, and BEH-TEBP in ESD exceeded significantly those in FD (P < 0.05). Normalising BFR concentrations to organic carbon content, did not alter these findings. This suggests that differences in BFR concentrations between different particle size fractions are caused by variations in particle surface area to volume ratio, rather than by variations in organic carbon content.

Bromine content and brominated flame retardants in food and animal feed from the UK

Current occurrence data for polybrominated diphenyl ethers (PBDE) and hexa-bromocyclododecane (HBCD) measured in most commonly consumed foods (n = 156) and animal feeds (n = 51) sampled in the UK, demonstrates an ongoing ubiquity of these contaminants in human and animal diets. PBDE concentrations for the sum of 17 measured congeners ranged from 0.02 ng/g to 8.91 ng/g whole weight for food, and 0.11 ng/g to 9.63 ng/g whole weight for animal feeds. The highest concentration ranges, and mean values were detected in fish, processed foods and fish feeds. HBCD diastereomers (alpha-HBCD was the most commonly detected) generally occurred at lower concentrations (from <0.01 ng/g to 10.1 ng/g for food and <0.01 ng/g to 0.66 ng/g for animal feed) and less frequently than PBDEs, but tetrabromobisphenol A which was also measured, was rarely detected. The total bromine content of the samples was also determined in an attempt to use a mass balance approach to investigate some of these samples for the occurrence of novel and emerging BFRs. Although the approach was further refined by measuring organic bromine content, the concentrations of bromine were too high (in most cases by orders of magnitude) to allow use of the approach. A selected sub-set of samples was screened by GC-MS, for the presence of novel/emerging brominated flame retardants (PBT, TBX, PBEB, DBHCTD, HCTBPH and OBTMPI) but these were not detected at the higher limits of detection that result from full scan (GC-MS) screening. This data will contribute to the EU wide risk assessment on these contaminants.

Sunlight Irradiation of Highly Brominated Polyphenyl Ethers Generates Polybenzofuran Products That Alter Dioxin-responsive mRNA Expression in Chicken Hepatocytes

We report on two highly brominated polyphenyl ether flame retardants, tetradecabromo-1,4- diphenoxybenzene (TeDB-DiPhOBz) and 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether (BDE-209), that formed photolytic degradation products in tetrahydrofuran (THF)/hexane solvent after 21 days of natural sunlight irradiation (SI). These degradation products of SI-TeDB-DiPhOBz and SI-BDE-209 included the numerous polybrominated homologue groups of polybenzofurans and dibenzofurans, respectively. Formation of similar polybenzofuran and dibenzofuran products was also observed following a 3 month exposure of the solid powder forms of TeDB-DiPhOBz and BDE-209 to natural SI. These resulting degradation product mixtures were administered to chicken embryonic hepatocytes (CEH) to determine effects on mRNA expression levels of 27 dioxin-responsive genes. For the solvent-based SI study, equivalent concentrations of 1 or 25 μM of SI-TeDB-DiPhOBz or 1 or 10 μM of SI-BDE-209 resulted in gene expression profiles that were similar to those of the most potent dioxin-like compound, 2,3,7,8-tetrachlorodibenzo-p-dioxin. In addition, a concentration-dependent induction of CYP1A4 and CYP1A5 mRNA was observed following exposure to SI-TeDB-DiPhOBz and SI-BDE-209. Based on ECthreshold values for CYP1A4/5 mRNA expression, relative potency (ReP) values were 1 × 10(-6) and 1 × 10(-5) for SI-TeDB-DiPhOBz and SI-BDE-209, respectively. The SI TeDB-DiPhOBz and BDE-209 powder degradation product mixture also significantly induced CYP1A4 mRNA levels in CEH. Our findings clearly show that the environmental stability of TeDB-DiPhOBz and BDE-209, and possibly other highly brominated polyphenyl ethers, is of great concern from a dioxin-like degradation products and toxicity perspective.

Physical-chemical properties and evaluative fate modelling of 'emerging' and 'novel' brominated and organophosphorus flame retardants in the indoor and outdoor environment

Several groups of flame retardants (FRs) have entered the market in recent years as replacements for polybrominated diphenyl ethers (PBDEs), but little is known about their physical-chemical properties or their environmental transport and fate. Here we make best estimates of the physical-chemical properties and undertake evaluative modelling assessments (indoors and outdoors) for 35 so-called 'novel' and 'emerging' brominated flame retardants (BFRs) and 22 organophosphorus flame retardants (OPFRs). A QSPR (Quantitative Structure-Property Relationship) based technique is used to reduce uncertainty in physical-chemical properties and to aid property selection for modelling, but it is evident that more, high quality property data are required for improving future assessments. Evaluative modelling results show that many of the alternative FRs, mainly alternative BFRs and some of the halogenated OPFRs, behave similarly to the PBDEs both indoors and outdoors. These alternative FRs exhibit high overall persistence (Pov), long-range transport potential (LRTP) and POP-like behaviour and on that basis cannot be regarded as suitable replacements to PBDEs. A group of low molecular weight alternative BFRs and non-halogenated OPFRs show a potentially better environmental performance based on Pov and LRTP metrics. Results must be interpreted with caution though since there are significant uncertainties and limited data to allow for thorough model evaluation. Additional environmental parameters such as toxicity and bioaccumulative potential as well as functionality issues should be considered in an industrial substitution strategy.

Halogenated flame-retardant concentrations in settled dust, respirable and inhalable particulates and polyurethane foam at gymnastic training facilities and residences

Halogenated flame-retardants (FRs) are used in a wide array of polymer-containing products. Animal studies and structure-activity modeling exercises suggest that FR exposure may result in detrimental toxicological effects. Workers with extended contact with such polymers (e.g., electronic dismantlers, carpet installers and aircraft personnel) have previously been observed to exhibit elevated body burdens of FRs, e.g., polybrominated diphenyl ethers (PBDEs). Recently, elevated PBDE blood levels were also reported in a non-occupational exposure group, gymnasts. These levels were hypothesized to be related to the large volumes of FR-treated polyurethane foam in gymnastics facilities. To further our understanding of workers' potential exposure, we analyzed FR concentrations in indoor dust and size-fractionated air particulates (respirable (<4 μm) and inhalable (>4 μm)) from gymnastic studios. Values were compared to samples from the homes of coaches employed at these facilities. Polyurethane foam blocks (i.e., pit foam) were also analyzed to characterize potential FR sources. FRs examined included those used to flame-retard polyurethane foam: 8 PBDE congeners, two brominated components of Firemaster 550 (2-ethylhexyl 2, 3, 4, 5-tetrabromobenzoate (TBB) and bis(2-ethylhexyl) 3, 4, 5, 6-tetrabromophthalate (TBPH)) and three chlorinated organophosphates (tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP) and tris(1,3-dichloro-2-propyl) phosphate (TDCPP)). Several additional FRs not used in polyurethane were also evaluated. These have also been detected in indoor dust and air and may also lead to adverse health effects. These include: BDE-183 and its replacement product (1, 2-bis(2, 4, 6-tribromophenoxy) ethane (BTBPE), two congeners of the deca-BDE formulation (BDE-206, -209) and their replacement decabromodiphenyl ethane (DBDPE) and hexabromocyclododecane (α-, β-, γ-HBCD), and tetrabromobisphenol-A (TBBPA)). Pit foam contained multiple FRs at cumulative concentrations of 12,100 to 25,800 μg g(-1), or 1.2% to 2.6% by weight. TBB and TBPH were the most abundant FRs detected, followed by TDCPP and several PBDEs. The mean total FR burden detected at the gyms was 8.6-fold higher (574 μg g(-1)) than that observed in the house dust samples (66.8 μg g(-1)). However, the polyurethane additives TBB and TDCPP were the only FRs that exhibited significantly greater levels (P<0.05) in gym than house dust. Mean levels of five FRs (BDE-99, -100, -153, -209 and TDCPP) were also higher in respirable particulates from the gyms than the homes and four FRs (BDE-47, TBB, TBPH and DBDPE) were higher at the homes than the gyms; these differences were not significant (P>0.05). Several additional FRs were detected in inhalable particulates; mean levels of BDE-66, -206 and TCPP were higher in the homes and BDE-47, -85, -99, -100, -153, -209, TBB, TBPH, and TDCPP were higher at the gyms. But, only the polyurethane additives i.e., BDE-100, TBB and TDCPP were significantly greater (P<0.05) in inhalable particulates from the gyms than at the homes. In conclusion, polyurethane foam collected from gymnastic studios exhibited a variety of FR compositional signatures; likely reflective of changes in FR usage over time and by different manufacturers. FR concentrations and compositional signatures also differed between settled dust, respirable and inhalable particulates between the gyms and homes. Concentrations of FRs used in polyurethane foam were higher in gym air and dust compared to homes, particularly TBB and TDCPP - which were also the primary FRs detected in the pit foam samples. Although these results should be interpreted with caution, as the sample size was small, these findings do suggest that FR concentrations observed in dust and air particulates from the gymnastic studios are further evidence that individuals frequenting these environments are at greater risk for exposure to these polymer additives.

Methodology and determination of tetradecabromo-1, 4-diphenoxybenzene flame retardant and breakdown by-products in sediments from the Laurentian Great Lakes

Tetradecabromo-1,4-diphenoxybenzene (TeDB-DiPhOBz) is a brominated polyphenyl ether flame retardant (FR) that is known to photolytically degrade to produce lower brominated polybrominated-diphenoxybenzenes (PB-DiPhOBzs), which may be precursors to MeO-PB-DiPhOBzs recently reported in the Great Lakes herring gulls eggs. To our knowledge, there are no reports on TeDB-DiPhOBz or other PB-DiPhOBz by-products in any environmental sample. The present study analyzed for the presence of PB-DiPhOBzs (including TeDB-DiPhOBz) and MeO-PB-DiPhOBzs in surficial sediment from sites in Saginaw Bay in western Lake Huron (n = 7), and in comparison to southern Lake Huron (open water) (n = 5) and Lake Erie (n = 3) sediment collected in the summers of 2012 or 2013. To analyze for possible PB-DiPhOBzs (Br14–Br0), the first known analytical method was developed for extraction and cleanup of sediment samples, and analysis by HPLC–atmospheric pressure photoionization (−)-quadrupole time-of-flight-mass spectrometry. The overall recovery efficiency was optimized to on average 33–104% progressing from Br14- to Br10-PB-DiPhOBzs. Br10- to Br14-PB-DiPhOBz detection and quantification limits ranged from 0.05 to 0.15 ng g(−1) dw and 0.17 to 0.49 ng g(−1) dw, respectively. Although this is the first report, PB-DiPhOBzs (Br14–Br10) and MeO-PB-DiPhOBzs were not detectable in any sediment sample. This included a site near the mouth of the highly FR-contaminated Saginaw River, near the confined disposal facility (CDF) located in Saginaw Bay at Channel-Shelter Island, which receives dredged sediment from the Saginaw River. Our findings suggest sediments from the presently studied sites in the Great Lakes ecosystem are not a sink for TeDB-DiPhOBz and PB-DiPhOBz by-product contaminants.

Thermal decomposition of 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), a novel brominated flame retardant

1,2-Bis(2,4,6-tribromophenoxy)ethane (BTBPE) is currently one of the most commonly applied novel brominated flame retardants. In this contribution, we analyze in detail the mechanisms pertinent to its thermal decomposition in view of analogous experimental findings. We demonstrate that a 1,3-hydrogen shift, leading to 2,4,6-tribromophenol (M9) and 1,3,5-tribromo-2-(vinyloxy)benzene (M10) molecules, dominates direct scission of O-CH2 bonds up to a temperature of ∼ 680 K. H atom abstraction from CH2 sites, followed by a fission of a C-C bond, produce a 2,4,6-tribromophenoxy radical (M2) and a M10 molecule. Bimolecular condensation reactions involving M2, M9, and M10 generate several congeners of brominated diphenyl ethers and their OH/OCHCH2 substituents, which serve as direct precursors for the formation of polybrominated dibenzo-p-dioxins. Reaction of M9 with a model compound of a hydrocarbon chain preferentially yields M2. Strong adsorption energy of the latter on a radical site of a hydrocarbon chain suggests that mechanisms such as Langmuir-Hinshelwood, Eley-Rideal, and Diels-Alder might be operating during the formation of PBDD/Fs from brominated flame retardants (BFRs). Reactions of alkyl primary/secondary radicals and diradical with the BTBPE molecule proceed via H abstraction from a -CH2- moiety.

Brominated flame retardant exposure of aircraft personnel

The use of brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) in aircraft is the result of high fire safety demands. Personnel working in or with aircraft might therefore be exposed to several BFRs. Previous studies have reported PBDE exposure in flight attendants and in passengers. One other group that may be subjected to significant BFR exposure via inhalation, are the aircraft maintenance workers. Personnel exposure both during flights and maintenance of aircraft, are investigated in the present study. Several BFRs were present in air and dust sampled during both the exposure scenarios; PBDEs, hexabromocyclododecane (HBCDD), decabromodiphenyl ethane (DBDPE) and 1,2-bis (2,4,6-tribromophenoxy) ethane. PBDEs were also analyzed in serum from pilots/cabin crew, maintenance workers and from a control group of individuals without any occupational aircraft exposure. Significantly higher concentrations of PBDEs were found in maintenance workers compared to pilots/cabin crew and control subjects with median total PBDE concentrations of 19, 6.8 and 6.6 pmol g(-1) lipids, respectively. Pilots and cabin crew had similar concentrations of most PBDEs as the control group, except for BDE-153 and BDE-154 which were significantly higher. Results indicate higher concentrations among some of the pilots compared to the cabin crew. It is however, evident that the cabin personnel have lower BFR exposures compared to maintenance workers that are exposed to such a degree that their blood levels are significantly different from the control group.

Emissions and fate of brominated flame retardants in the indoor environment: a critical review of modelling approaches

This review explores the existing understanding and the available approaches to estimating the emissions and fate of semi-volatile organic compounds (SVOCs) and in particular focuses on the brominated flame retardants (BFRs). Volatilisation, an important emission mechanism for the more volatile compounds can be well described using current emission models. More research is needed, however, to better characterise alternative release mechanisms such as direct material-particle partitioning and material abrasion. These two particle-mediated emissions are likely to result in an increased chemical release from the source than can be accounted for by volatilisation, especially for low volatile compounds, and emission models need to be updated in order to account for these. Air-surface partitioning is an important fate process for SVOCs such as BFRs however it is still not well characterised indoors. In addition, the assumption of an instantaneous air-particle equilibrium adopted by current indoor fate models might not be valid for high-molecular weight, strongly sorbing compounds. A better description of indoor particle dynamics is required to assess the effect of particle-associated transport as this will control the fate of low volatile BFRs. We suggest further research steps that will improve modelling precision and increase our understanding of the factors that govern the indoor fate of a wide range of SVOCs. It is also considered that the appropriateness of the selected model for a given study relies on the individual characteristics of the study environment and scope of the study.