A new class of contaminants of concern? A comprehensive review of liquid crystal monomers.

Liquid crystal monomers (LCMs) are a class of emerging contaminants of concern predicted to be persistent, bioaccumulative and toxic (PBT). Being one of the key components in liquid crystal displays (LCDs), the disposal of LCD containing devices is closely related to the emission of LCMs into the environment. LCMs have been detected in a wide range of environmental matrices including dust, sediment, soil, sewage leachate, and air, with concentration ranges between 17 and 2121 ng/g found in indoor residential dust. Furthermore, they have been detected on human skin at concentrations up to 2,071,000 ng/m2 and in the serum of e-waste dismantling workers, at concentrations ranging from 3.9 to 276 ng/mL. Despite the far-reaching contamination of these compounds, there is limited knowledge of their environmental behaviour, fate, and toxicity. Model predictions show that 297 of 330 LCMs are persistent and bioaccumulative compounds, with many more indicated as being toxic. However, current knowledge of their physicochemical and PBT properties is largely restricted to theoretical predictions and limited to a small number of experimental toxicity studies. As an emerging class of contaminants of concern, a lack of standardisation between studies was identified as a key challenge to advancing the state of knowledge of these compounds. Not only are harmonised analytical methods for their determination and quantification in environmental media yet to be established, but there is also a need for a universal abbreviation system. To further harmonise the reporting of data on LCMs we propose reporting the sum concentration of ten priority LCMs, selected on the basis detection frequency, toxicity and potential for human exposure. Of the ten priority LCMs five are fluorinated biphenyls and analogues, four are biphenyls/bicyclohexyls and analogues and one is a cyanobiphenyl.

A Rapid Screening Method for the Detection of Additives in Electronics and Plastic Consumer Products Using AP-MALDI-qTOF-MS.

A novel method was developed and optimized for the fast-screening analysis of additives in electronics and plastic consumer products using atmospheric pressure matrix-assisted laser desorption ionization (AP-MALDI) coupled with a high-resolution quadrupole time-of-flight (qTOF) mass spectrometer (MS). To simplify sample preparation and increase sample throughput, an innovative 48 well graphene nanoplatelets (GNP) doped AP-MALDI target plate was developed. The GNP incorporated in the target plate fulfilled the role of the MALDI matrix and, therefore, sample extracts could be directly transferred to the AP-MALDI 48 well target plate and analyzed without a subsequent matrix addition. The homogeneously dispersed and immobilized GNP target plates also provided increased signal intensity and reproducibility. Furthermore, analytical standards of various plastic additives and plastic products with known concentrations of additives were studied to assess the AP-MALDI ionization mechanisms and method capability. The analysis time was 15 s per measurement using an automated sequence. The GNP-doped target plates exhibited high desorption/ionization of low molecular weight molecules (<1000 Da) and can be used in both positive and negative ionization modes. The AP-MALDI-qTOF-MS method was applied to screen for additives in various electronics and plastic consumer products. Suspect screening was performed using a database containing 1366 compounds. A total of 56 additives including antioxidants, flame retardants, plasticizers, UV-stabilizers, and UV-filters were identified (confidence level 4). Identification of certain plastic additives in plastic children's toys may indicate that they are recycled from waste electronic and electronic equipment (WEEE).

Discovery and quantification of plastic particle pollution in human blood.

Plastic particles are ubiquitous pollutants in the living environment and food chain but no study to date has reported on the internal exposure of plastic particles in human blood. This study's goal was to develop a robust and sensitive sampling and analytical method with double shot pyrolysis - gas chromatography/mass spectrometry and apply it to measure plastic particles ≥700 nm in human whole blood from 22 healthy volunteers. Four high production volume polymers applied in plastic were identified and quantified for the first time in blood. Polyethylene terephthalate, polyethylene and polymers of styrene (a sum parameter of polystyrene, expanded polystyrene, acetonitrile butadiene styrene etc.) were the most widely encountered, followed by poly(methyl methacrylate). Polypropylene was analysed but values were under the limits of quantification. In this study of a small set of donors, the mean of the sum quantifiable concentration of plastic particles in blood was 1.6 µg/ml, showing a first measurement of the mass concentration of the polymeric component of plastic in human blood. This pioneering human biomonitoring study demonstrated that plastic particles are bioavailable for uptake into the human bloodstream. An understanding of the exposure of these substances in humans and the associated hazard of such exposure is needed to determine whether or not plastic particle exposure is a public health risk.

Migration of hazardous contaminants from WEEE contaminated polymeric toy material by mouthing.

This study evaluated the migration of brominated flame retardants (BFRs), phosphate flame retardants (PFRs), bisphenols (BPA, BPF), and phthalate ester-based plasticizers from recycled polymeric toy material, containing waste electrical and electronic equipment (WEEE), in artificial saliva simulating 1 h of mouthing. In total 12 parts of 9 different toys were tested in triplicate after confirming WEEE specific contamination. Up to 11 contaminants were detected in saliva from one toy sample. The highest migration rate up to 128 ng/(cm2 x h) was found for BPA followed by bis(2-ethylhexyl) phthalate (DEHP) and diisobutyl phthalate (DIBP) with migration rates up to 25.5 and 8.27 ng/(cm2 x h), respectively. In addition to DecaBDE, which was detected in 3 saliva samples at migration rates between 0.09 and 0.31 ng/(cm2 x h), the decaBDE replacements 2,4,6-tris(2,4,6-tribromophenoxy)-1,3,5-triazine (TTBP-TAZ), decabromodiphenyl ethane (DBDPE), resorcinol bis(diphenyl phosphate) (RDP), and hexabromocyclododecane (HBCDD) were detected as well with comparable migration rates. 2,4,6-tribromphenol (246-TBP) reached migration rates up to 1.15 ng/(cm2 x h) in correspondence to the presence of TTBP-TAZ. Tetrabromobisphenol A (TBBPA), BPA, 246-TBP, DEHP, DIBP and triphenyl phosphate (TPHP) were predominantly observed in saliva with a detection frequency between 50 and 75%. Daily intake (DI) values were calculated for relevant analytes and compared to tolerable daily intake (TDI) values. The highest DI values of 72.4, 14.3, 5.74, 2.28 and 2.09 ng/(kg BW x day), were obtained for BPA, DEHP, DIBP, TBBPA, and TPHP, respectively. None of them exceed the TDI value or respective reference dose (RfD).

Chlorinated paraffins and tris (1-chloro-2-propyl) phosphate in spray polyurethane foams - A source for indoor exposure?

In this study, we investigated chemical additives present in new and used spray polyurethane foams (SPFs) and assessed the dermal transfer through direct contact. This first study shows that cured do-it-yourself spray one-component SPFs (OCFs) often contain chlorinated paraffins (C14-C37), and tris (1-chloro-2-propyl) phosphate (TCIPP), ranging 0.2-50%, and 0.9-30% w/w, respectively. Six OCFs contained CP levels ranging 22-50% w/w, whereas nine OCFs used for similar applications only contained CP levels ranging 2-17% w/w. It is unclear if the combination CPs/TCIPP is meant to improve the flame retardancy of products, and could suggest an unnecessary use of high CPs/TCIPP concentrations in OCFs. The two-component SPFs (TCFs) contained only TCIPP with levels ranging from 7.0% to 9.0%. The CPs and TCIPP were easily transferred from cured OCFs to the hands. Levels up to 590 µg per hand for CPs and up to 2.7 µg per hand for TCIPP were found. After end-of-life, it is challenging to recycle used SPFs. They may, therefore, end up at landfills where the TCIPP/CPs may leach into the environment. Therefore, further investigation is needed to assess potential exposure risks associated with general and occupational use, and the impact of landfill leaching on the environment.

Optimization of a low flow sampler for improved assessment of gas and particle bound exposure to chlorinated paraffins.

An optimized low volume sampler was developed to determine both gas- and particle bound concentrations of short and medium-chain chlorinated paraffins (S/MCCPs). Background contamination was limited by the sampler design, providing method quantification limits (MQLs) at least two orders of magnitude lower than other studies within the gas (MQL: 500 pg (ΣSCCPs), 1.86 ng (ΣMCCPs)) and particle (MQL: 500 pg (ΣSCCPs), 1.72 ng (ΣMCCPs) phases. Good repeatability was observed between parallel indoor measurements (RSD ≤ 9.3% (gas), RSD ≤ 14% (particle)) with no breakthrough/saturation observed after a week of continuous sampling. For indoor air sampling, SCCPs were dominant within the gas phase (17 ± 4.9 ng/m3) compared to MCCPs (2.7 ± 0.8 ng/m3) while the opposite was observed in the particle bound fraction (0.28 ± 0.11 ng/m3 (ΣSCCPs) vs. 2.7 ± 1.0 ng/m3 (ΣMCCPs)). Only SCCPs in the gas phase could be detected reliably during outdoor sampling and were considerably lower compared to indoor concentrations (0.27 ± 0.10 ng/m3). Separation of the gas and particle bound phase was found to be crucial in applying the appropriate response factors for quantification based on the deconvoluted S/MCCP sample profile, thus avoiding over- (gas phase) or underestimation (particle phase) of reported concentrations. Very short chain chlorinated paraffins (vSCCPs, C5-C9) were also detected at equal or higher abundance compared to SCCP congener groups (C10-C13) congener groups, indicating an additional human indoor inhalation risk.

Decabromodiphenylether trends in the European environment: Bird eggs, sewage sludge and surficial sediments.

Concern on relatively high levels and the potential bioaccumulation of decabromodiphenylether (BDE209) has led to a European 8-year monitoring program on trends in BDE209 concentrations in birds, sewage sludge and sediments from seven countries. BDE209 was analysed in four environmental matrices: sparrowhawk eggs (UK), glaucous gull eggs (Bear Island, Norway), sewage sludge (UK, Ireland and the Netherlands) and sediment (France, Germany, the Netherlands, UK and Ireland). BDE209 was detected in most of the glaucous gull and sparrow hawk eggs but neither increasing nor decreasing trends in these BDE209 levels were observed. An indication for debromination of BDE209 in sparrowhawk eggs was found. BDE209 concentrations in sediments ranged from very low ng/g (88 ng/g on an organic carbon (OC) basis) concentrations, in the rivers Elbe, Ems, Seine and the Outer Humber, to high µg/g (120 µg/g OC), in the Western Scheldt, Liverpool Bay and River Mersey. Apart from decreasing values in the Western Scheldt sediment no further decreases in BDE209 concentrations were observed over time, neither in sediment nor in sewage sludge showing that the voluntary emissions control program of the bromine industry only had a local effect. In contrast to the sewage sludge samples from the Netherlands (mean 355 ng/g dry weight (dw) or 1026 ng/g OC), the BDE209 concentrations in the UK increased at all sites from 2006 to 2011 (8092 ng/g dw or 22,367 ng/g OC). The BDE209 levels in several UK sediments and sewage sludge were still very high at the end of the program in 2012, most likely caused by frequent use of BDE209 in the textile industry. This may be indicative of the persistence of BDE209 and the limited degradation into lower brominated congeners in sediment, although it cannot be excluded that ongoing BDE209 emissions have played a role as well.

In vitro biotransformation and evaluation of potential transformation products of chlorinated paraffins by high resolution accurate mass spectrometry.

Chlorinated paraffins (CPs) are high production chemicals, which leads to their ubiquitous presence in the environment. To date, few studies have measured CPs in humans and typically at relatively low concentrations, despite indications that exposure may be high compared to various persistent organic pollutants. The aim of this study is to investigate the in vitro biotransformation of CPs by human liver fractions. We determined the changes of the CP concentrations after the enzymatic transformation with human liver microsomes using a two-tiered in vitro approach. CP concentrations decreased with human liver microsomes, with the decreases of 33-94% after incubating with different groups of enzymes for 2 h. The profiles of CP rapidly shifted after the incubation with human liver microsomes. In addition, the concentrations of CPs and the biotransformation products were tentatively measured using high-resolution mass spectrometric analysis, including very short CP (carbon chain length <10), alcohols, ketones, and carboxylic acids. C‒C bond cleavage is a potential transformation pathway for CPs, and ketones are potential products of CP biotransformation, especially for long-chain CPs (C>17). The ketone products may be investigated as CP exposure biomarker in biomonitoring studies.

Short-, medium-, and long-chain chlorinated paraffins in South African indoor dust and cat hair.

Polychlorinated n-alkanes or chlorinated paraffins (CPs) contain a magnitude of structural isomers and are categorized as short-chain (SCCPs), medium-chain (MCCPs), and long-chain (LCCPs) CPs, according to the carbon chain lengths. In this study the Æ©SCCPs, Æ©MCCPs, and Æ©LCCP concentrations are reported for South African indoor dust and pet cat hair. The median concentrations of the Æ©CPs (C9-C37) ranged from 33 to 663 µg/g for freshly collected dust (FD), 36-488 µg/g for dust collected from household vacuum cleaner bags (VD), and 1.2-15 µg/g for cat hair (CH) samples. MCCPs were the dominant CP group, followed by SCCPs and LCCPs. The Æ©MCCP concentration ranged from 13 to 498 µg/g in dust and 0.6-6.5 µg/g in cat hair. SCCPs with shorter carbon chains and lower chlorine substitution were observed in cat hair. LCCPs with carbon chains > C20 were detected in dust and hair samples, possibly indicating the use of wax grade LCCP formulations. Non-traditional Kendrick mass defect plots were used to obtain information on the magnitude of CPs and provide evidence of possible interfering compounds. This is the first report on the occurrence of SCCPs, MCCPs, and LCCPs in the South African indoor environment.

Brominated and organophosphorus flame retardants in South African indoor dust and cat hair.

Flame retardants (FRs), such as brominated flame retardants (BFRs) and organophosphorus flame retardants (OPFRs), are diverse groups of compounds used in various products related to the indoor environment. In this study concentrations of eight polybrominated diphenyl ethers (PBDEs), two alternative BFRs and ten OPFRs were determined in indoor dust (n = 20) and pet cat hair (n = 11) from South Africa. The OPFRs were the major FRs, contributing to more than 97% of the total FR concentration. The median Ʃ10OPFRs concentrations were 44,800 ng/g in freshly collected dust (F-dust), 19,800 ng/g in the dust collected from vacuum cleaner bags (V-dust), and 865 ng/g in cat hair (C-hair). Tris(1-chloro-2-propyl) phosphate (TCIPP) was the dominant OPFR in the dust samples with median concentrations of 7,010 ng/g in F-dust and 3,590 ng/g in V-dust. Tris(2-butoxyethyl) phosphate (TBOEP) was the dominant OPFR in C-hair, with a median concentration of 387 ng/g. The concentrations of Ʃ8PBDEs were higher in F-dust than in V-dust. BDE209 was the dominant BFR in all three matrices. Bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5- tetrabromobenzoate (EH-TBB) showed notable contributions to the BFR profile in cat hair. A worst-case dust exposure estimation was performed for all analytes. The estimated TCIPP daily intake through dust ingestion was up to 1,240 ng/kg bw for toddlers. The results indicate that OPFRs are ubiquitous in South African indoor environment. Indoor dust is a major source of human exposure to environmental contaminants. This can for example occur through hand-to-mouth contact of toddlers, and is an important route of exposure to currently used FRs accumulated on dust particles. The presence of FRs, in particular high concentrations of OPFRs, suggests that children and indoor pet cats may have greater exposure to FRs than adults.

Chlorinated Paraffins in Car Tires Recycled to Rubber Granulates and Playground Tiles.

Chlorinated paraffins (CPs) are used in various products to improve their physicochemical characteristics. Due to recycling, CPs may end up in "new" recycled products. In this study we investigated CPs present in end-of-life car tires that are recycled to rubber granulates used on artificial soccer fields, and playground tiles. The ∑CP(C10-C30) concentrations ranged from 1.5 to 67 µg/g in car tires, 13-67 µg/g in rubber granulates, and 16-74 µg/g in playground tiles. MCCPs were the dominant CP group with an average contribution of 72%. LCCPs up to C30, were detected for the first time in car tires, rubber granulates, and playground tiles. The CPs application in tires is unclear, the low CP concentrations found in this study (<0.007%) could possibly indicate contamination during the manufacturing process. The presence of CPs in the granulates and tiles, in addition to the multiple chemicals already detected, emphasizes the need to further investigate the migration and leaching behavior, in order to assess potential risks of CPs for humans and the environment. The presence of CPs in car tires may be another source of CPs for the environment. The CP volume brought into the environment by tire wear particles (TWP) from car tires in the European Union, is estimated at 2.0-89 tons annually.

Chlorinated paraffins in indoor dust from Australia: Levels, congener patterns and preliminary assessment of human exposure.

Chlorinated paraffins (CPs) are a group of polychlorinated n-alkanes with high production volumes. Until now, there are only limited data on the levels of CPs in the environment, especially in the indoor environment. In this study, dust samples were collected from 44 indoor environments, including 27 private houses, 10 offices, and 7 vehicles. Short-, medium-, and long-chain CPs were detected in all dust samples. The median concentration of ∑CPs (C10-C21) was 57, 160 and 290 µg/g, in houses, offices, and vehicles, respectively. Medium-chain CPs were the dominant group, on average accounting for 86% of ∑CPs. Cl6 and Cl8 groups had the highest contributions to ∑CPs across all the different microenvironments, while C13 and C14 were the predominant groups of SCCPs and MCCPs. Median exposure to ∑CPs via indoor dust were estimated at 80 ng/kg/day and 620 µg/kg/day for Australian adults and toddlers respectively. The daily intake of CPs via dust, in the worse scenario, was still 2-3 orders of magnitudes lower than the reference doses based on neoplastic effects.

Medium-Chain Chlorinated Paraffins (CPs) Dominate in Australian Sewage Sludge.

To simultaneously quantify and profile the complex mixture of short-, median-, and long-chain CPs (SCCPs, MCCPs, and LCCPs) in Australian sewage sludge, we applied and further validated a recently developed novel instrumental technique, using quadrupole time-of-flight high resolution mass spectrometry running in the negative atmospheric pressure chemical ionization mode (APCI-qTOF-HRMS). Without using an analytical column the cleaned extracts were directly injected into the qTOF-HRMS followed by quantification of the CPs by a mathematical algorithm. The recoveries of the four SCCP, MCCP and LCCP-spiked sewage sludge samples ranged from 86 to 123%. This APCI-qTOF-HRMS method is a fast and promising technique for routinely measuring SCCPs, MCCPs, and LCCPs in sewage sludge. Australian sewage sludge was dominated by MCCPs with concentrations ranging from 542 to 3645 ng/g dry weight (dw). Lower SCCPs concentrations (<57-1421 ng/g dw) were detected in the Australian sewage sludge, which were comparable with the LCCPs concentrations (116-960 ng/g dw). This is the first time that CPs were reported in Australian sewage sludge. The results of this study gives a first impression on the distribution of the SCCPs, MCCPs, and LCCPs in Australia wastewater treatment plants (WWTPs).

Children's exposure to polybrominated diphenyl ethers (PBDEs) through mouthing toys.

Polybrominated diphenyl ethers (PBDEs) have previously been detected in children toys, yet the risk of child exposure to these chemicals through the mouthing of toys or other items is still unknown. We aimed to expand on the current knowledge by investigating the impact of infants' mouthing activities on exposure to PBDEs present in toys. This was established by a leaching model for determining the amount PBDEs that can leach from toys into saliva in simulated conditions. The PBDE migration rate was at its highest for the 15 min low-exposure scenario incubations (198 pg/cm(2) × min) with the ERM EC-591 certified reference material (CRM) (0.17% w/w PBDEs). The leaching process was congener-dependent, since the percentage of lower brominated PBDE congeners that leached out was up to 4.5 times higher than for the heavier PBDEs. To study the scenario in which a child would mouth on a toy flame retarded with BDE 209 alone, a plastic item containing 7% BDE 209 (w/w) was also tested. The BDE 209 amounts leached out in only 15 min were higher than the amounts leached from the CRM after the 16 h incubation. For the Belgian population, the exposure scenario from mouthing on toys containing PBDEs in amounts similar to the REACH threshold was found to be lower than the exposure from mother's milk, but higher than the exposure through diet or even dust.

Wastewater analysis of Census day samples to investigate per capita input of organophosphorus flame retardants and plasticizers into wastewater.

The use of organophosphate esters (PFRs) as flame retardants and plasticizers has increased due to the ban of some brominated flame retardants. There is however some concern regarding the toxicity, particularly carcinogenicity and neurotoxicity, of some of the PFRs. In this study we applied wastewater analysis to assess use of PFRs by the Australian population. Influent samples were collected from eleven wastewater treatment plants (STPs) in Australia on Census day and analysed for PFRs using gas chromatography coupled with mass spectrometry (GC-MS). Per capita mass loads of PFRs were calculated using the accurate Census head counts. The results indicate that tris(2-butoxyethyl) phosphate (TBOEP) has the highest per capita input into wastewater followed by tris(2-chloroisopropyl) phosphate (TCIPP), tris(isobutyl) phosphate (TIBP), tris(2-chloroethyl) phosphate (TCEP) and tris(1,3-dichloroisopropyl) phosphate (TDCIPP). Similar PFR profiles were observed across the Australian STPs and a comparison with European and U.S. STPs indicated similar PFR concentrations. We estimate that approximately 2.1 mg person(-1) day(-1) of PFRs are input into Australian wastewater which equates to 16 tonnes per annum.

Tracing organophosphorus and brominated flame retardants and plasticizers in an estuarine food web.

Nine organophosphorus flame retardants (PFRs) were detected in a pelagic and benthic food web of the Western Scheldt estuary, The Netherlands. Concentrations of several PFRs were an order of magnitude higher than those of the brominated flame retardants (BFRs). However, the detection frequency of the PFRs (6-56%) was lower than that of the BFRs (50-97%). Tris(2-butoxyethyl) phosphate (TBOEP), tris(isobutyl) phosphate (TIBP) and tris(2-chloroisopropyl) phosphate (TCIPP) were the dominant PFRs in sediment with median concentrations of 7.0, 8.1 and 1.8 ng/g dry weight (dw), respectively. PFR levels in the suspended particular matter (SPM) were 2-12 times higher than that in sediment. TBOEP, TCIPP, TIBP, tris(2-chloroethyl) phosphate (TCEP) and tris(phenyl) phosphate (TPHP) were found in organisms higher in the estuarine food web. The highest PFR concentrations in the benthic food web were found in sculpin, goby and lugworm with median concentrations of 17, 7.4, 4.6 and 2.0 ng/g wet weight (ww) for TBOEP, TIBP, TCIPP and TPHP, respectively. Comparable levels were observed in the pelagic food web, BDE209 was the predominant PBDE in sediment and SPM with median concentrations up to 9.7 and 385 ng/g dw, respectively. BDE47 was predominant in the biotic compartment of the food web with highest median levels observed in sculpin and common tern eggs of 79 ng/g lipid weight (lw) (2.5 ng/g ww) and 80 ng/g lw (11 ng/g ww), respectively. Trophic magnification was observed for all PBDEs with the exception of BDE209. Indications of trophic magnification of PFRs were observed in the benthic food web for TBOEP, TCIPP and TCEP with tentative trophic magnification factors of 3.5, 2.2 and 2.6, respectively (p<0.05). Most of the other PFRs showed trophic dilution in both food webs. The relative high PFR levels in several fish species suggest high emissions and substantial exposure of organisms to PFRs in the Western Scheldt.

Organophosphorus flame retardants (PFRs) and plasticizers in house and car dust and the influence of electronic equipment.

All nine PFRs studied were detected in house and car dust from the Netherlands with the exception of tris(butyl) phosphate (TNBP) and tris(isobutyl) phosphate (TIBP) in car dust. Tris(2-butoxyethyl) phosphate (TBOEP, median 22 µg g(-1)) was dominant in house dust collected around and on electronics followed by tris(2-chloroisopropyl) phosphate (TCIPP, median 1.3 µg g(-1)), tris(2-chloroethyl) phosphate (TCEP, median 1.3 µg g(-1)) and tris(phenyl) phosphate (TPHP, median 0.8 µg g(-1)). Levels of TPHP and tris(methylphenyl) phosphate (TMPP, also known as TCP) in house dust on electronics were significantly higher than in house dust collected around electronics, suggesting that electronic equipment has limited contribution to the PFR levels in house dust, with the exception of TPHP and TMPP. Car dust was dominated by tris(1,3-dichloroisopropyl) phosphate (TDCIPP) with the highest levels found in dust collected from the car seats (1100 µg g(-1)). The mean TDCIPP and TCIPP levels observed in car dust were significantly higher than the levels observed in dust collected around electronics. Significantly higher mean TMPP levels in dust taken from car seats were found compared to dust collected around the equipment (p<0.05). This is probably influenced by the use of TDCIPP, TCIPP in polyurethane foam (car seats) and the use of TMPP as plasticizer in car interiors. Worldwide four PFR patterns were observed in house dust. The PFR pattern in the Netherlands of TDCIPP, TMPP, TCEP, TCIPP and TPHP in house dust is comparable to the pattern found in six other countries, which may point to identical sources of these PFRs in the indoor environment. However, the PFR levels between the countries and within countries showed high variation.

Dust measurement of two organophosphorus flame retardants, resorcinol bis(diphenylphosphate) (RBDPP) and bisphenol A bis(diphenylphosphate) (BPA-BDPP), used as alternatives for BDE-209.

Resorcinol bis(diphenylphosphate) (RBDPP) and bisphenol A bis(diphenylphosphate) (BPA-BDPP) are two halogen-free organophosphorus flame retardant (PFRs) that are used as an alternative for the decabromodiphenyl ether (Deca-BDE) technical mixture in TV/flatscreen housing and other electronic consumer products. In this study, dust samples were collected from various microenvironments in The Netherlands (houses, cars), Greece (houses), and Sweden (apartments, cars, furniture stores, electronics stores) and analyzed for RBDPP and BPA-BDPP. Additionally, the dust samples from The Netherlands were analyzed for decabromodiphenyl ether (BDE-209) for comparison and for TPHP, which is a byproduct in the RBDPP and BPA-BDPP technical products. BPA-BDPP was detected in almost all dust samples from The Netherlands, Greece, and Sweden. Highest concentrations were found in dust samples collected on electronic equipment from all three countries with BPA-BDPP levels ranging from <0.1 to 1300 µg/g and RBDPP levels from <0.04 to 520 µg/g. RBDPP and BPA-BDPP levels in dust collected further away from the electronics (source) were usually lower. BDE-209 levels in The Netherlands dust samples collected on and around the electronics were similar and much lower than the BPA-BDPP/RBDPP levels, indicating that the electronics were not the source of BDE-209. Strong positive correlations were found between TPHP concentrations and those of RBDPP (r = 0.805) and BPA-BDPP (r = 0.924), probably due to TPHP being a byproduct in commercial RBDPP and BPA-BDPP mixtures in electronics. To our knowledge, this is the first time that RBDPP and BPA-BDPP were detected in dust samples from Europe.

Effect-directed analysis to explore the polar bear exposome: identification of thyroid hormone disrupting compounds in plasma.

Compounds with transthyretin (TTR)-binding potency in the blood plasma of polar bear cubs were identified with effect-directed analysis (EDA). This approach contributes to the understanding of the thyroid disrupting exposome of polar bears. The selection of these samples for in-depth EDA was based on the difference between the observed TTR-binding potency on the one hand and the calculated potency (based on known concentrations of TTR-binding compounds and their relative potencies) on the other. A library-based identification was applied to the liquid chromatography-time-of-flight-mass spectrometry (LC-ToF-MS) data by screening for matches between compound lists and the LC-ToF-MS data regarding accurate mass and isotope pattern. Then, isotope cluster analysis (ICA) was applied to the LC-ToF-MS data allowing specific screening for halogen isotope patterns. The presence of linear and branched nonylphenol (NP) was observed for the first time in polar bears. Furthermore, the presence of one di- and two monohydroxylated octachlorinated biphenyls (octaCBs) was revealed in the extracts. Linear and branched NP, 4'-OH-CB201 and 4,4'-OH-CB202 could be successfully confirmed with respect to their retention time in the analytical system. In addition, branched NP, mono- and dihydroxylated-octaCBs showed TTR-binding potencies and could explain another 32 ± 2% of the total measured activities in the extracts.