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

Polybrominated diphenyl ethers in indoor dust from Brazil: assessing demographic differences and human health exposure

Indoor house dust is considered an important human exposure route to polybrominated diphenyl ethers (PBDEs), which has raised concern about their environmental persistence and toxicity properties. In this study, eight PBDEs (BDE-28, -47, -99, -100, -153, -154, -183, and -209) were determined in house dust from two cities with different socio-demographic characteristics from Brazil, examining possible relationships with factors that potentially influence contamination (population density, economic activities, presence of electronic equipment, and so on) and also estimating the risk of human exposure through oral ingestion and dermal contact. The Σ8PBDE concentration in Sorocaba city ranged between 380 and 4269 ng/g dw, while in Itapetininga city ranged from 106 to 1000 ng/g dw. In both regions, BDE-209 was the most abundantly found congener, followed by BDE-99. House dust from Sorocaba presented significantly greater concentrations of BDE-183 and BDE-209 than Itapetininga. Regarding risk exposure assessment, the estimated daily intake (EDI) of PBDEs was much lower than their respective reference doses (RfDs) in all pathways estimated (non-dietary ingestion and dermal contact). This study provided valuable data to improve the knowledge about the presence and exposure to PBDEs in Brazilian house dust in comparison to other developing countries and the need to control environmental pollution and protect human health.

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

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

Update of the risk assessment of polybrominated diphenyl ethers (PBDEs) in food

The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE-28, -47, -49, -99, -100, -138, -153, -154, -183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE-47, -99, -153, -209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint-specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners 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 Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.

Are UK E-waste recycling facilities a source of environmental contamination and occupational exposure to brominated flame retardants?

Investigations into the impacts of regulated electrical and electronic waste (e-waste) recycling activities on urban environments in Europe remain rather scarce. In this study, dust samples taken both inside and outside of five UK e-waste recycling facilities were analysed for concentrations of polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and hexabromocyclododecane (HBCDD). Average concentrations of ∑BFRs in dust inside and outside UK e-waste recycling facilities were 12,000 ng/g and 180 ng/g, with median concentrations of 7500 ng/g and 85 ng/g, respectively. BDE-209 and decabromodiphenyl ethane (DBDPE) were the most abundant BFRs in both indoor and kerb dust, making a combined contribution to ∑BFRs of ~90 % on average. While four out of the five studied e-waste facilities showed a lack of significant impact on BFR contamination in surrounding environment, one of the studied e-waste recycling facilities was identified as a likely source of BFR contamination to UK urban environments, with industrial activities as another potential source of NBFRs. Occupational exposure of UK e-waste recycling workers to BFRs via dust ingestion was generally lower than that estimated for e-waste recyclers from other countries, but was comparable to BFR exposure via dust ingestion of UK office workers. Our estimates suggested that health burdens posed by dust ingestion of BFRs were minimal for UK e-waste recycling workers.

Organophosphate flame retardants and plastics in soil from an abandoned e-waste recycling site: significant ecological risks derived from plastic debris

The distribution of 9 organophosphate flame retardants (OPFRs) was determined in plastic debris and soil samples separated from twenty soil samples collected from an abandoned e-waste recycling area. Tris-(chloroisopropyl) phosphate (TCPP) and triphenyl phosphate (TPhP) were the main chemicals, with median concentrations of 124-1930 ng/g and 143-1170 ng/g in soil, and 712-803 ng/g and 600-953 ng/g in plastics, respectively. Plastics contributed less than 10% of the total OPFR mass in bulk soil samples. No apparent OPFR distribution trend was observed in different sizes of plastics and soil. The ecological risks of plastics and OPFRs were estimated by the species sensitivity distributions (SSDs) method, which resulted in lower predicted no-effect concentrations (PNECs) of TPhP and decabromodiphenyl ether 209 (BDE 209) than the standard values derived from limited toxicity tests. In addition, the PNEC of polyethene (PE) was lower than the plastic concentration in the soil of a previous study. TPhP and BDE 209 had high ecological risks with risk quotients (RQs) > 0.1, and RQ of TPhP was among the highest values in literature.

Silicone wristbands as personal passive sampling devices: Current knowledge, recommendations for use, and future directions

Personal chemical exposure assessment is necessary to determine the frequency and magnitude of individual chemical exposures, especially since chemicals present in everyday environments may lead to adverse health outcomes. In the last decade, silicone wristbands have emerged as a new chemical exposure assessment tool and have since been utilized for assessing personal exposure to a wide range of chemicals in a variety of populations. Silicone wristbands can be powerful tools for quantifying personal exposure to chemical mixtures in a single sample, associating exposure with health outcomes, and potentially overcoming some of the challenges associated with quantifying the chemical exposome. However, as their popularity grows, it is crucial that they are used in the appropriate context and within the limits of the technology. This review serves as a guide for researchers interested in utilizing silicone wristbands as a personal exposure assessment tool. Along with briefly discussing the passive sampling theory behind silicone wristbands, this review performs an in-depth comparison of wristbands to other common exposure assessment tools, including biomarkers of exposure measured in biospecimens, and evaluates their utility in exposure assessments and epidemiological studies. Finally, this review includes recommendations for utilizing silicone wristbands to evaluate personal chemical exposure and provides suggestions on what research is needed to recognize silicone wristbands as a premier chemical exposure assessment tool.

Quantitative fatty acid signature analysis (QFASA) in indoor dust: Implication for tracking indoor source accumulation of organic pollutant exposure

Indoor dust has been used as a proxy for estimating human indoor pollutant exposure risks, yet source identification remains challenging. This study tentatively investigated whether quantitative fatty acid signature analysis (QFASA) of dust, could be applied to indicate sources and their respective contributions for a major class of indoor organic pollutants organophosphate flame retardants (OPFRs). We observed significant correlations between OPFR concentrations and lipid content (p < 0.05) in house dusts. Using 15 signature fatty acids (FAs) in various indoor sources and the QFASA model, we found that clothing (39.1% in Australia and 36.5% in China) was the predominant contributing vector of dust OPFR followed by cooking oil and pet hair. Among these sources, clothing materials were proposed to be important vectors introducing organic pollutants to the indoor environment. Our QFASA contribution estimation analyses allowed for accurate prediction of most OPFR concentrations in clothing, validating our findings that clothing materials may serve as important carrier for OPFRs in indoor migration. This is the first study attempting to identify sources of organic pollutants using QFASA in an indoor setting and will provide important insight into the transfer of organic pollutants in indoor environment.

A meta-analysis of factors influencing concentrations of brominated flame retardants and organophosphate esters in indoor dust

Current assessments of human exposure to flame retardants (FRs) via dust ingestion rely on measurements of FR concentrations in dust samples collected at specific points in time and space. Such exposure assessments are rendered further uncertain by the possibility of within-room and within-building spatial and temporal variability, differences in dust particle size fraction analysed, as well as differences in dust sampling approach. A meta-analysis of peer-reviewed data was undertaken to evaluate the impact of these factors on reported concentrations of brominated flame retardants (BFRs) and organophosphate esters (OPEs) in dust and subsequent human exposure estimates. Except for a few cases, concentrations of FRs in elevated surface dust (ESD) exceeded significantly those in floor dust (FD). The implications of this for exposure assessment are not entirely clear. However, they imply that analysing FD only will underestimate exposure for adults who likely rarely ingest floor dust, while analysing ESD only would overestimate exposure for toddlers who likely rarely ingest elevated surface dust. Considerable within-building spatial variability was observed with no specific trend between concentrations of either BFRs or OPEs in living rooms and bedrooms in the same homes, implying that exposure assessments based solely on sampling one room are uncertain. Substantial differences in FR concentrations were observed in different particle size fractions of dust. This is likely partly attributable to the presence of abraded polymer particles/fibres with high FR concentrations in larger particle size fractions. This has implications for exposure assessment as adherence to skin and subsequent FR uptake via ingestion and dermal sorption varies with particle size. Analysing dust samples obtained from a householder vacuum cleaner (HHVC) compared with researcher collected dust (RCD) will underestimate human exposure to the most of studied contaminants. This is likely due to the losses of volatile FRs from HHVC dust over the extended period such dust spends in the dust bag. Temporal variability in FR concentrations is apparent during month-to-month or seasonal monitoring, with such variability likely due more to changes in room contents rather than seasonal temperature variation.

Brominated Flame Retardants in Children's Room: Concentration, Composition, and Health Risk Assessment

Children spend most of their daily time indoors. Many of the items used indoors, such as furniture, electronics, textile, and children toys, are treated with chemicals to provide longevity and fulfil the safety standards. However, many chemicals added to these products are released into the environment during leaching out from the treated products. Many studies have reported brominated flame retardants (BFRs) in indoor environments; however, few have focused on environments specified for young children. In this study, paired air (PM₁₀) and dust samples were collected from the rooms (n = 30) of Saudi children. These samples were analyzed for different congeners of polybrominated diphenyl ethers (PBDEs) and three important alternative flame retardants using gas chromatography-mass spectrometry. Decabromodiphenyl ether (BDE 209) was the most important analyzed BFR in dust and PM₁₀ samples with a median value of 3150 ng/g of dust and 75 pg/m³. This indicates the wider application of BDE 209 has implications for its occurrence, although its use has been regulated for specified uses since 2014. Among alternative BFRs, 2-Ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB), Bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH), and 1,2-Bis(2,4,6-tribromophenoxy)ethane (BTBPE) were found with a median levels of 10, 15 and 8 ng/g of dust, respectively. However, alternative BFRs were present in <50% of the PM₁₀ samples. The calculated long term and daily exposures via indoor dust and PM₁₀ of Saudi children from their rooms were well below the respective reference dose (RfD) values. Nonetheless, the study highlights BDE 209 at higher levels than previously reported from household dust in Saudi Arabia. The study warrants further extensive research to estimate the different classes of chemical exposure to children from their rooms.

Emerging investigator series: air conditioning filters as a sampler for semi-volatile organic compounds in indoor and near-building air

Organic compounds like flame retardants (FRs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs) are consistently found in both indoor and outdoor environments. There are many possible matrices for measurement of these compounds (e.g. indoor dust, air - passive and active air samples), but all methods have limitations, like the heterogeneous distribution of indoor dust, or noisy active air samplers. We used filters from building-wide heating, ventilation and air conditioning (HVAC) units to evaluate levels of PAHs, PCBs, OCPs and NFRs in indoor and outdoor environments, and to evaluate whether this method is feasible for screening semivolatile organic compounds (SVOCs) in indoor and near-building outdoor environments. Detectable levels of FRs, PCBs, OCPs and PAHs were found, demonstrating that HVAC filters do collect SVOCs, with generally higher levels of PAHs in the incoming air filters and higher levels of PCBs, OCPs and FRs in the outgoing air filters. Levels of FRs, PCBs and OCPs in outgoing air were comparable to those measured using conventional active air sampling in the same building. The advantages of using HVAC filters are (1) integrated and homogeneous samples, as the whole building is sampled over typically a long timescale (months), and (2) samples are easy and cheap to collect and do not require prior deployment of samplers. The key disadvantage is that HVAC filters are not designed for analytical chemistry and thus the filter materials can have variable or unknown gas sorption and particle capture, and can have strong matrix effects during analysis.

Occurrence and partitioning of brominated flame retardants (BFRs) in indoor air and dust: a 15-month case study in a test home

Ten polybrominated diphenyl ethers (PBDEs) and 16 novel brominated flame retardants (NBFRs) were measured in air and dust samples collected in a test home in Harbin, China, from January 2017 to June 2018. The PBDE and NBFR concentrations in indoor air were in the ranges of 0.598-14.5 pg m^-3 and 9.28-686 pg m^-3, respectively. The ranges of the PBDE and NBFR concentrations in indoor dust were 221-1060 ng g^-1 and 71.9-1160 ng g^-1, respectively. Brominated flame retardant (BFR) concentrations in indoor air were affected by the temperature, relative humidity (RH), and ventilation. The BFR concentrations in indoor dust did not show temperature dependence. All dust samples were sieved into 6 size fractions (F1-F6: 1000-2000 μm, 500-1000 μm, 250-500 μm, 125-250 μm, 63-125 μm, and < 63 μm). The mass percentage of BFRs in F6 was the highest. The BFR concentrations did not increase constantly with a particle size decrease, and the concentrations in F2 were higher than those in F3. The partitioning behavior of BFRs illustrates that the dust-air partitioning coefficient approximately approached equilibrium within F5, F6, and the total dust fraction (FA) in the test home when logK_OA was between 9.1 and 11.32. Air-dust fugacity fractions were calculated, and the results suggested that most of the BFRs were mainly transferred from air to dust in the indoor environment for F1-F6.

First insight into human extrahepatic metabolism of flame retardants: Biotransformation of EH-TBB and Firemaster-550 components by human skin subcellular fractions

2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB) and a mixture of EH-TBB, Bis(2-ethylhexyl)tetrabromphthalate (BEH-TEBP) and Triphenyl phosphate (TPhP), prepared in a ratio similar to the Firemaster-550™ (FM550) flame retardant formulation, were exposed to human skin subcellular fractions (S9) to evaluate their dermal in vitro metabolism for the first time. After 60 min of incubation, tetrabromobenzoic acid (TBBA) and diphenyl phosphate (DPhP) were identified as the major metabolites of EH-TBB and TPhP, respectively using UPLC-Q-Exactive Orbitrap™-MS analysis. Dermal biotransformation of EH-TBB and TPhP was catalyzed by skin carboxylesterases rather than CYP450 enzymes, while no stable metabolites could be identified for BEH-TEBP. Metabolite formation rates of EH-TBB as individual compound and as a component of FM550 fitted the Michaelis-Menten model, while no steady state could be reached for TPhP under experimental conditions. Estimated maximum metabolic rate (V_max) for TBBA formation upon exposure to FM550 was lower than V_max for EH-TBB (1.08 and 15.2 pmol min^-1 mg protein^-1, respectively). This indicates dermal metabolism would contribute less to the clearance of EH-TBB body burden than hepatic metabolism (V_max = 644 pmol min^-1 mg protein^-1). Implications for human exposure include EH-TBB accumulation in skin tissue and human exposure to dermal metabolic products, which may have different toxicokinetic and toxicodynamic parameters than parent flame retardants.

Legacy PBDEs and NBFRs in sediments of the tidal River Thames using liquid chromatography coupled to a high resolution accurate mass Orbitrap mass spectrometer

Surface sediment samples (n = 45) were collected along a 110 km transect of the river Thames in October 2011, starting from Teddington Lock out through the industrial area of London to the southern North Sea. Several legacy and novel brominated flame retardants (NBFRs) were analysed, including 13 polybrominated diphenyl ethers (PBDEs) (congeners 17, 28, 47, 99, 100, 153, 154, 183, 196, 197, 206, 207 and 209), hexabromocyclododecane (HBCDDs), tetrabromobisphenol A (TBBPA), hexabromobenzene (HBB), 2,4,6-tribromophenol (TBP), 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (EH-TBB or TBB), bis(2-ethylhexyl) tetrabromophthalate (BEH-TEBP or TBPH), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), pentabromoethylbenzene (PBEB), anti/syn-dechlorane plus (a/s-DP), 2,2',4,4',5,5'-hexabromobiphenyl (BB153) and α-,β-1,2-dibromo-4-(1,2-dibromoethyl) cyclohexane (α-,β-DBE-DBCH or TBECH). A novel analysis method based on liquid chromatographic separation, followed by high resolution accurate mass detection using the Orbitrap platform was used for quantification. Results revealed that BDE-209 had the highest concentrations (<0.1 to 540 μg kg^-1 dw) and detection frequency, accounting for 95% of all PBDE congeners measured. Indicative evidence of debromination of the PentaBDE technical mixture was observed through elevated relative abundance of BDE-28 in sediment compared to the Penta-BDE formulation. NBFRs were detected at comparable levels to PBDEs (excluding BDE-209), which indicates increasing use of the former. Spatial trend analysis showed that samples from industrial areas had significantly higher concentrations of Σ₁₂PBDEs, ΣHBCDDs, TBBPA, BEH-TEBP, BTBPE and TBP. Three locations showed high concentrations of HBCDDs with diastereomer patterns comparable to the technical mixture, which indicate recent input sources to the sediment.

Distributions of organophosphate flame retardants (OPFRs) in three dust size fractions from homes and building material markets

The distributions of organophosphate flame retardants (OPFRs) in various size fractions of indoor dust samples from homes (H; n = 18) and building material markets (B; n = 7) in the Rhine/Main region of Germany were investigated. Three particle size fractions (F1: 150-200 μm, F2: 63-150 μm, and F3: <63 μm) and bulk dust (BD) subsamples (<200 μm) of each sample were analyzed for 10 OPFRs. On average, the total OPFR concentrations (∑₁₀OPFR) in bulk dust and all three size fractions from building material markets were 133, 153, 196, and 88.0 μg/g in subsamples B-BD, B-F1, B-F2, and B-F3. These concentrations were at least five times higher than those in bulk dust and all three size fractions from homes, with values of 19.3, 17.2, 19.5, and 18.7 μg/g for subsamples H-BD, H-F1, H-F2, and H-F3, respectively. Tris(2-chloroisopropyl)phosphate (TCIPP) was the dominant congener in dust from building material markets, contributing over 91% to the ∑₁₀OPFR of B-BD and all particle size fractions. Meanwhile, both tris(2-butoxyethyl)phosphate (TBOEP) and TCIPP were abundant in dust from homes, respectively contributing 28%-41% and 31%-43% to the ∑₁₀OPFR of H-BD and all particle size fractions. Most of the OPFR concentrations showed no consistent trend with particle size. However, TCIPP was more likely to be enriched in F2. Microscopic examination indicated that TCIPP in indoor dust mainly originated from abraded fragments of commercial products. In contrast, TBOEP accumulated in F3, related to direct transfer of floor-care products to fine dust particles. The concentrations of OPFRs were not significantly correlated with total organic carbon contents in any particle size fraction. However, evaluation of their mass contributions showed that more than 85% of OPFRs accumulated in particles smaller than 150 μm, indicating that this particle size fraction is most suitable for monitoring of OPFRs.

Phthalates and organophosphates in settled dust and HVAC filter dust of U.S. low-income homes: Association with season, building characteristics, and childhood asthma

Phthalates and organophosphates are ubiquitous indoor semi-volatile organic contaminants (SVOCs) that have been widely used as plasticizers and flame retardants in consumer products. Although many studies have assessed their levels in house dust, only a few used dust samples captured by filters of building heating, ventilation, and air conditioning (HVAC) systems. HVAC filters collect particles from large volumes of air over a long period of time (potentially known) and thus provide a spatially and temporally integrated concentration. This study measured concentrations of phthalates and organophosphates in HVAC filter dust and settled floor dust collected from low-income homes in Texas, United States, in both the summer and winter seasons. The most frequently detected compounds were benzyl butyl phthalate (BBzP), di-(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DnOP), tris (1-chloro-2-propyl) phosphate (TCIPP), triphenyl phosphate (TPHP), and tris (1,3-dichloroisopropyl) phosphate (TDCIPP). The median level of TCIPP in settled dust was 3- to 180-times higher than levels reported in other studies of residential homes. Significantly higher concentrations were observed in HVAC filter dust as compared to settled dust for most of the frequently detected compounds in both seasons, except for several phthalates in the winter. SVOC concentrations in settled dust in winter were generally higher than in summer, while different seasonality patterns were found for HVAC filter dust. Settled dust samples from homes with vinyl flooring contained significantly higher levels of BBzP and DEHP as compared to homes with other types of floor material. The concentration of DEHP and TDCIPP in settled dust also significantly associated with the presence of carpet in homes. Cleaning activities to remove dust from furniture actually increased the levels of certain compounds in HVAC filter dust, while frequent vacuuming of carpet helped to decrease the concentrations of some compounds in settled dust. Additionally, the size and age of a given house also correlated with the levels of some pollutants in dust. A statistically significant association between DEHP concentration in HVAC filter dust in summer and the severity of asthma in children was observed. These results suggest that HVAC filter dust represents a useful sampling medium to monitor indoor SVOC concentrations with high sensitivity; in contrast, when using settled dust, in addition to consideration of seasonal influences, it is critical to know the sampling location because the type and level of SVOCs may be related to local materials used there.

Challenges in the Analysis of Novel Flame Retardants in Indoor Dust: Results of the INTERFLAB 2 Interlaboratory Evaluation

The Interlaboratory Study of Novel Flame Retardants (INTERFLAB 2) was conducted by 20 laboratories in 12 countries to test the precision and accuracy of the analysis of 24 "novel" flame retardants (NFRs). Laboratories analyzed NFRs in injection-ready test mixtures, in extracts of residential dust, and in residential dust to evaluate the influence of dust handling and extraction. For test mixtures, mean reported concentrations of PBT, PBEB, EH-TBB, TBBPA, TBDP-TAZTO, TBOEP, α-TBCO, β-DBE-DBCH, and total HBCDD differed by >25% relative to reference values. Coefficients of variation were higher in dusts/dust extracts than in test mixtures. Concentrations among laboratories ranged over 3-4 orders of magnitude for HBB, TBP-DBPE, TBP-AE, and TDCIPP in dust extracts and dusts. Most laboratories produced repeatable dust concentrations, but differences reported in the literature among laboratories of <70% could be due to analytical variability, and the attribution of such differences to other causes should be made with caution. Most variations in accuracy and precision were introduced by matrix effects and/or sample processing, rather than instrumental analysis. We recommend recovery correction to improve accuracy. There is a need to improve analytical methods and to validate methods on complex matrices such as standard reference materials for dust or spiked matrices.

Levels, occurrence and human exposure to novel brominated flame retardants (NBFRs) and Dechlorane Plus (DP) in dust from different indoor environments in Hangzhou, China

In this work, sixteen novel brominated flame retardants (NBFRs) and Dechlorane Plus (DP) were investigated in dust samples collected from different indoor environments (home, office, laboratory, classroom and dormitory) in Hangzhou, China. High detection frequencies for most of the congeners were observed, suggesting the widespread use of NBFRs and DP. The mean concentrations of ∑₁₆NBFRs were 389ngg^-1 in the home dust, 1125ngg^-1 in the office dust, 204ngg^-1 in the laboratory dust, 259ngg^-1 in the classroom dust, and 825ngg^-1 in the dormitory dust. Regarding DP, the mean concentrations of DP were 106ngg^-1 in the office dust, 59ngg^-1 in the dormitory dust, 56ngg^-1 in the classroom dust, 52ngg^-1 in the home dust, and 40ngg^-1 in the laboratory dust. The concentrations of NBFRs and DP in the indoor dust were positively related to the number of indoor electric appliances and negatively related to the air ventilation rate. The age of the interior decoration has a profound effect on the concentration of NBFRs in indoor dust. The daily exposure doses (DED) of NBFRs and DP were estimated to be 4595pg (kgbw)^-1d^-1 for toddlers and 1099pg (kgbw)^-1d^-1 for adults. Thus, toddlers have a higher risk for NBFRs exposure than adults. The DED of young adults in college in different indoor microenvironments decreased in the following order: dormitory (657pg (kg bw)^-1d^-1)>laboratory (145pg (kgbw)^-1d^-1)>classroom (140pg (kgbw)^-1d^-1). More attention should be paid to the exposure of young adults to indoor pollutants, which has not previously been the subject of great concern.

Occurrence of polybrominated diphenyl ethers in floor and elevated surface house dust from Shanghai, China

House dust is the main source of human exposure to flame retardants by ingestion. This study investigated the occurrence of polybrominated diphenyl ethers (PBDEs) in indoor dust from 22 houses in Shanghai, China. House dust was separately collected from the floor and elevated furnishings surface (mostly between 0.5 and 2 m height) for comparison. The concentrations of ∑₂₂ PBDEs ranged from 19.4 to 3280 ng/g (with a geometric mean of 203 ng/g) and from 55.1 to 792 ng/g (with a geometric mean of 166 ng/g) in floor dust (FD) and elevated surface dust (ESD), respectively. BDE-209 was the predominant congener, accounting for about 73.1% of total PBDE burdens. In terms of congener profiles, the comparison of FD and ESD revealed no significant differences except for the ratio of BDE-47/BDE-99. ESD samples displayed a ratio of BDE-47/BDE-99 very similar to commercial penta-BDE products DE-71 while the ratio in FD was exceptionally higher. Significant correlation was found between concentrations of commercial penta-BDE compositions in FD and ESD (p < 0.05). Except for some occasional values, PBDE levels in house dust exhibited temporal stability. Human exposure to PBDEs via dust ingestion was estimated. The highest daily intake of PBDEs was for toddlers by using 95th percentile concentrations of PBDEs via high dust ingestion in FD (23.07 ng/kg bw/day). About 20-fold difference in exposure estimates between toddlers and adults supports that toddlers are facing greater risk from indoor floor dust. Expectedly, this study highlighted the point that residents in Shanghai were exposed to low doses of PBDEs in house dust.

Occurrence and distribution of organophosphate flame retardants (OPFRs) in soil and outdoor settled dust from a multi-waste recycling area in China

Distribution of 12 organophosphate flame retardants (OPFRs) was determined in soil and outdoor settled dust samples collected from a multi-waste (electronic, plastic, and rubber wastes and abandoned household-appliances and vehicles) recycling area, that encompassed different modes of operation i.e. open (ORS) and semi-closed recycling (SCRS). Among the twelve OPFRs analyzed, eleven were detected at a frequency of 75%-100% in all soil and dust samples. In soil samples, ΣOPFR concentrations were significantly higher at ORS (122-2100ng/g) than at SCRS (58.5-316ng/g) and nearby farmlands (37.7-156ng/g). The ΣOPFR concentrations in dust samples were higher than those in soil samples with spatial distribution similar to that observed for soil, decreasing from ORS (1390-42,700ng/g) to SCRS (914-7940ng/g). Tris(2-chloroisopropyl) phosphate (TCIPP) was the major OPFRs in both soil (<MDL-1370ng/g) and dust (39.9-16,300ng/g) samples. Chlorinated OPFRs [TCIPP, tris(1,3-dichloroisopropyl) phosphate (TDCIPP) and tris(2-chloroethyl) phosphate (TCEP)] and aryl-OPFRs [triphenyl phosphate (TPHP), tris(methylphenyl) phosphate (TMPP)] exhibited spatial difference between ORS and SCRS. Principle component analysis (PCA) of OPFR concentrations revealed that TCIPP, TDCIPP, TPHP, TMPP originated from similar sources. TMPP was assessed to pose eco-toxicological risk (risk quotient values: RQs) in the soil ecosystem. The median estimated daily intake (EDI) of OPFRs via soil and outdoor settled dust ingestion (based on average ingestion rate) was 3.14×10^-1ng/kgbw/day for adults at ORS. Our results suggest that waste recycling is an important source of chlorinated- and aryl-OPFRs in the environment.

Preliminary assessment on exposure of four typical populations to potentially toxic metals by means of skin wipes under the influence of haze pollution

To investigate the exposure risk of human beings to nine potentially toxic metals (PTMs), namely, Cu, Cr, Zn, As, Cd, Pb, Ni, Mn, and Co, skin wipe samples were collected from four types of populations, namely, children, undergraduates, security guards, and professional drivers, under different haze pollution levels in Xinxiang, China by using Ghost wipes. The Ghost wipes were quantitatively analyzed by inductively coupled plasma mass spectrometry (ICP-MS) after microwave digestion. Generally, Zn (ND-1350μg/m² for undergraduates, ND-2660μg/m² for security guards, ND-2460μg/m² for children, and ND-2530μg/m² for professional drivers) showed the highest concentration among the four populations, followed by Cu (0.02-83.4μg/m² for undergraduates, ND-70.2μg/m² for security guards, 23.2-487μg/m² for children, and ND-116μg/m² for professional drivers). As (ND-5.7μg/m² for undergraduates, ND-2.3μg/m² for security guards, ND-21.1μg/m² for children, and ND-11.0μg/m² for professional drivers) and Co (ND-6.0μg/m² for undergraduates, ND-7.9μg/m² for security guards, ND-13.4μg/m² for children, and ND-2.1μg/m² for professional drivers) showed the lowest concentrations in all populations. Remarkable differences were found among the four populations and PTM levels decreased in the following order: children, professional drivers, security guards, and undergraduates. Gender variation was discovered for undergraduates and children. Generally, PTM contamination in skin wipes collected during a light haze pollution level was generally higher than that during a heavy haze pollution level, but PTM contamination was comparable between the two haze pollution levels for children. Non-carcinogenic exposure risks to As, Cd, and Pb for all populations were higher than those for the other six elements but all of them were within the acceptable safety threshold, indicating no apparent non-carcinogenic risk.

Within-room and within-home spatial and temporal variability in concentrations of legacy and "novel" brominated flame retardants in indoor dust

To test the hypothesis that assessments of human exposure to PBDEs and NBFRs (PBEB, EH-TBB, BEH-TEBP, BTBPE and DBDPE) via dust ingestion should take into account spatial and temporal variability in dust contamination; 238 dust samples were collected from nine different rooms within three homes in Birmingham UK. In each room, three different dust samples were taken at monthly intervals for nine months, one sample from elevated surfaces and two samples from two different floor areas. Substantial within-room and within-home spatial variability in BFR concentrations was apparent between two floor areas and between different rooms due to the varying distances of sampled surfaces from potential BFR sources. With the exception of DBDPE, BFR concentrations in elevated surface dust exceeded significantly those in floor dust. Considerable within-room and within-home temporal variability in BFR concentrations was also apparent over a nine month sampling period. This is likely attributable to changes in room contents. Based on observed spatial and temporal variability, exposure estimates based on analysis of a single dust sample taken from one specific floor area at one specific point in time may not be entirely representative of human exposure in that room. Noticeable variability in BFR concentrations was also observed between colder and warmer seasons. In 13 out of 17 floor areas, concentrations of Σ₈tri-deca-BDEs were higher in colder seasons, while those of Σ₅NBFRs were higher in warmer seasons. Significant negative correlation was observed in two rooms between concentrations of BDE-99, Σ₇tri-hepta-BDEs and BEH-TEBP and dust loading (g/m²).

Legacy and novel brominated flame retardants in interior car dust - Implications for human exposure

Brominated flame retardants (BFRs) are organobromine compounds with an inhibitory effect on combustion chemistry tending to reduce the flammability of products. Concerns about health effects and environmental threats have led to phase-out or restrictions in the use of Penta-, Octa- and Deca-BDE technical formulations, increasing the demand for Novel BFRs (NBFRs) as replacements for the banned formulations. This study examined the occurrence of legacy and NBFRs in the dust from the interior of private cars in Thessaloniki, Greece, aged from 1 to 19 years with variable origin and characteristics. The determinants included 20 Polybrominated Diphenyl Ethers (PBDEs) (Di-to Deca-BDEs), four NBFRs such as Decabromodiphenylethane (DBDPE), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (TBB), and bis(2-ethylhexyl)-3,4,5,6-tetrabromophthalate (TBPH), three isomers of hexabromocyclododecane (HBCD), and tetrabromobisphenol A (TBBPA). The concentrations of ∑₂₀PBDE ranged from 132 to 54,666 ng g^-1 being dominated by BDE-209. The concentrations of ∑₄NBFRs ranged from 48 to 7626 ng g^-1 and were dominated by DBDPE, the major substitute of BDE-209. HBCDs ranged between <5 and 1745 ng g^-1, with alpha-HBCD being the most prevalent isomer Finally, the concentrations of TBBPA varied from <10 to 1064 ng g^-1. The concentration levels and composition profiles of BFRs were investigated in relation to the characteristics of cars, such as year of manufacture, country of origin, and interior equipment (type of car seats, electronic and electrical components, ventilation, etc.). The average daily intakes of selected BFRs (BDE-47, BDE-99, BDE-153, BDE-209, TBB, BTBPE, TBPH, DBDPE, HBCDs and TBBPA) via ingestion and dermal absorption were estimated for adults and toddlers. The potential health risk due to BFRs was found to be several orders of magnitude lower than their corresponding reference dose (RfD) values.

Polyhalogenated compounds (chlorinated paraffins, novel and classic flame retardants, POPs) in dishcloths after their regular use in households

Dishcloths are routinely used in the clean-up process following daily kitchen activities and are thus subject to contamination commensurate with their frequent use. Here we analyzed dishcloths for the occurrence of polyhalogenated compounds after 14days of use in household kitchens. Analysis of 19 dishcloths revealed the presence of 29 polyhalogenated contaminants with total mean/median concentrations of 6,900/3,600ng/dishcloth, respectively. The spectrum featured classic and novel halogenated flame-retardants (HFRs) like polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), decabromodiphenyl ethane (DBDPE), pentabromoethylbenzene (PBEB), chlordene plus and dechlorane plus, as well as typical chloropesticides and background contaminants (e.g. hexachlorobenzene (HCB), p,p'-dichlorodiphenyldichloroethene (p,p'-DDE), polychlorinated biphenyls (PCBs) and lindane). The individual dishcloths showed highly variable fingerprints of polyhalogenated compounds. If present, medium-chain chlorinated paraffins (MCCPs) were by far the most prominent compound class with up to 55,400ng/dishcloth. Without consideration of chlorinated paraffins, the mean concentration of other polychlorinated compounds (270ng/dishcloth) was generally one order of magnitude lower than the mean concentration of brominated flame retardants (BFRs) (1,700ng/dishcloth). Our study verified that a wide range of polyhalogenated compounds is readily available in the kitchen environment. Furthermore, dishcloths are ordinarily handled without gloves or hand protection, given the observed concentrations of polyhalogenated compounds in dishcloths, such handling may serve as an additional exposure pathway for human users. Evaluation of this thesis was supported by conduction of a dermal uptake assessment.

Influence of sampling approach on concentrations of legacy and "novel" brominated flame retardants in indoor dust

The study investigates the impact of sampling method on the concentrations of PBDEs (BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209) and NBFRs (PBEB, EH-TBB, BEH-TEBP, BTBPE and DBDPE) in indoor dust. A total of 36 dust samples were collected from 12 homes in Birmingham, UK (3 samples per home comprising researcher collected dust - both RCD from the living room (RCDL) and bedroom (RCDB), with an additional householder vacuum dust sample - HHVD). BDE-209 was the predominant compound, with average concentrations of 2642, 2336 and 2634 ng/g in RCDL, RCDB and HHVD respectively. The next most abundant BFR was BEH-TEBP, followed by DBDPE, with average concentrations of 306, 339 and 233 ng/g for BEH-TEBP and 155, 91 and 152 ng/g for DBDPE in RCDL, RCDB and HHVD respectively. Average concentrations of Σ₆tri-hexa-BDEs were 47, 41, and 24 ng/g in RCDL, RCDB and HHVD respectively. With the exception of Σ₆tri-hexa-BDEs, BDE-153, BDE-99 and to some extent BEH-TEBP, no significant differences were found between BFR concentrations in RCD and HHVD. Statistically significant correlations were observed between concentrations of Σ₆tri-hexa-BDEs, BEH-TEBP and DBDPE in HHVD and in both RCDL and RCDB. However, comparison of estimates of exposure via dust ingestion based on these two sampling methods revealed that using householder vacuum dust underestimates exposure, particularly for Σ₆tri-hexa-BDEs, and to some extent for BEH-TEBP. In contrast, HHVD could be a viable alternative to RCD as a metric of exposure for higher brominated BFRs.

Effects of food-borne exposure of juvenile rainbow trout (Oncorhynchus mykiss) to emerging brominated flame retardants 1,2-bis(2,4,6-tribromophenoxy)ethane and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate

Brominated flame retardants (BFRs) represent a large group of chemicals used in a variety of household and commercial products to prevent fire propagation. The environmental persistence and toxicity of some of the most widely used BFRs has resulted in a progressive ban worldwide and the development of novel BFRs for which the knowledge on environmental health impacts remains limited. The objectives of this study were to evaluate the effects of two emerging BFRs, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE) and 2-ethylhexyl-2,3,4,5-tetrabromobenzoate (EH-TBB), in diet exposed juvenile rainbow trout (Oncorhynchus mykiss). Both compounds were detected in fish carcasses at 76% and 2% of the daily dosage of BTBPE and EH-TBB, respectively, indicating accumulation of BTBPE and by contrast extensive depuration/metabolism of EH-TBB. Liver gene transcription analysis using RNA-sequencing indicated that the chronic 28-d dietary exposure of trout to EH-TBB down-regulated one single gene related to endocrine-mediated processes, whereas BTBPE impacted the transcription of 33 genes, including genes involved in the immune response, reproduction, and oxidative stress. Additional analysis using qRT-PCR after 48-h and 28-d of exposure confirmed the impact of BTBPE on immune related genes in the liver (apolipoprotein A-I, lysozyme) and the head-kidney (complement c3-4). However, the activity of lysozymes measured at the protein level did not reflect transcriptomic results. Overall, results suggested an impact on immune-related gene transcription in BTBPE exposed fish, as well as oxidative stress and endocrine disruption potentials.

Prevalence of historical and replacement brominated flame retardant chemicals in New York City homes

BACKGROUND

Until their phase-out between 2005 and 2013, polybrominated diphenyl ethers (PBDEs) were added to household products including furniture, rugs, and electronics to meet flammability standards. Replacement brominated flame retardant (BFR) chemicals, including 2-ethylhexyl-2,3,4,5 tetrabromobenzoate (TBB) and bis(2-ethylhexyl) 2,3,4,5-tetrabromophthalate (TBPH), which are components of the Firemaster 550^® commercial mixture, are now being used to meet some flammability standards in furniture. The objective of this analysis was to evaluate the extent to which mothers and their children living in New York City are exposed to PBDEs, TBB, and TBPH.

METHODS

We measured PBDEs, TBB, and TBPH using gas chromatography mass spectrometry in dust (n = 25) and handwipe (n = 11) samples collected between 2012 and 2013 from mothers and children living in New York City. We defined dust as enriched if the proportional distribution for a given BFR exceeded two-thirds of the total BFR content.

RESULTS

We detected PBDEs and TBPH in 100% of dust and handwipe samples and TBB in 100% of dust samples and 95% of handwipe samples. Dust from approximately two-thirds of households was enriched for either PBDEs (n = 9) or for TBB + TBPH (n = 8). Overall, the median house dust concentration of TBB + TBPH (1318 ng/g dust) was higher than that of ΣPentaBDE (802 ng/g dust) and BDE-209 (1171 ng/g dust). Children generally had higher BFR handwipe concentrations compared to mothers (ΣPentaBDE: 73%, BDE-209: 64%, TBB + TBPH: 55%) and within households, BFR concentrations from paired maternal-child handwipes were highly correlated. Among mothers, we found a significant positive relation between house dust and handwipe BDE-209 and TBB + TBPH concentrations.

CONCLUSION

PBDEs, TBB and TBPH are ubiquitous in house dust and handwipes in a sample of mother-child pairs residing in New York City.