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A Prussian blue (PB)-based sodium-ion battery (SIB) is a promising candidate in large-scale electric energy storage. However, its development is hindered by the poor cyclability of the PB cathode a...

This study investigated the occurrence of 19 aryl phosphates and mixed alkyl-aryl phosphates in dust samples (n = 144) collected under the Canadian House Dust Study (CHDS). The predominant target analytes, detected in 100 % of the samples, were isodecyl diphenyl phosphate (IDDPP), cresyl diphenyl phosphate (CDPP), and isopropylated triaryl phosphates (ITPs), with median concentrations of 1225 (248–17850) ng/g, 91 (14–57700) ng/g, and 805 (203–152000) ng/g, respectively. ITPs included isopropylphenyl diphenyl phosphate (IPPDPP), bis(isopropylphenyl) phenyl phosphate (BIPPPP), and tris(isopropylphenyl) phosphate (TIPPP). Strong correlations were found among IPPDPP, BIPPPP, and TIPPP, suggesting that there might be various consumer and building products containing mixtures of these substances. Bisphenol A bis(diphenyl phosphate) (BPA-DP) and resorcinol bis(diphenyl phosphate) (RBDP) were detected in 69 % and 78 % of samples, with relatively low median concentrations of 30 (max: 818) ng/g and 14 (max: 307) ng/g, respectively. Since the usage of OPEs as flame retardants has increased over the past decade, the current levels of OPEs in Canadian house dust could be higher than those reported in this study, where the samples were collected in 2007–2010. Further monitoring of OPEs in various environmental and biological matrices is recommended.

There is growing interest in the identification of novel aryl organophosphate triester (OPTE) congeners that may exist in the environment. In this study, we discovered 11 novel aryl OPTEs in north China house dust using a characteristic aryl phosphate fragment-guided high-resolution mass spectrometry method with data-independent acquisition. Tripentylated triphenyl phosphate (TPeTPhP), dicresyl phenyl phosphate (DCrPP), diisodecylphenyl phosphate (DIDPP), butoxyethoxyethyl octyl phenyl phosphate (BEEOPP), dioctyl nonylphenyl phosphate (DONPP), propoxypropyl bis(diphenyl phosphate) (PPBDPhP), octyl nonylphenyl phenyl phosphate (ONPPP), and (saturated mono-oxygen butoxybutyl) butoxyethoxyethyl phenyl phosphate (MBBPP) were detected in 84-100% of 45 samples. ONPPP was present in the highest median concentration of 69.0 ng/g, followed by DONPP (68.7 ng/g), DIDPP (50.3 ng/g), BEEOPP (42.5 ng/g), DCrPP (33.7 ng/g), PPBDPhP (25.0 ng/g), TPeTPhP (9.28 ng/g), and MBBPP (4.80 ng/g). Seven novel aryl OPTEs were also detected in standard house dust SRM2585, and the concentration of DIDPP (4375 ± 660 ng/g) was 4-fold higher than that (1048 ± 44.5 ng/g) of triphenyl phosphate, a typical aryl OPTE. The discovery of these novel OPTEs has significantly enriched our understanding of the aryl OPTEs present in house dust.

The possibility of controlling the composition of a mixture of triphenyl phosphate, p-tert-butylphenyl diphenyl phosphate, di(p-tert-butylphenyl)phenyl phosphate, and tri(p-tert-butylphenyl) phosphate, formed by transesterification of triphenyl phosphate with p-tert-butylphenol, was demonstrated. The amount of p-tert-butylphenol necessary for transesterification of triphenyl phosphate to yield a mixture of phosphates of required composition was determined. If necessary, the composition of the phosphates can be adjusted by selective distillation of triphenyl phosphate in a vacuum.

This paper presents the findings of an international online survey designed to better understand current practices and knowledge surrounding cellulose-based films showing signs of vinegar syndrome ...

Lewis base/Brønsted acid cocatalysis for electrophilic thiocyanation of olefins is reported. Using a combination of triphenylphosphine selenide and diphenyl phosphate as a catalyst, a wide range of unsaturated amides and thioamides underwent thiocyanation to furnish thiocyanated thiazoline and oxazoline derivatives in high yields (up to 97%).

Exposure to polybrominated diphenyl ether (PBDE) flame retardants (FRs) could have adverse effects on neurodevelopment in children. Some organophosphate (OPFRs) are used as alternatives for the phased-out decabromodiphenylether such as resorcinol bis(diphenyl phosphate (PBDPP) and bisphenol A bis(diphenyl phosphate (BPA-BDPP). This study aims to investigate the relationship between indoor OPFR exposure and neurodevelopmental behavior in children. OPFRs were measured in house dust and hand wipes from 42 children, aged 8-16 months, from the LInking maternal Nutrition to Child health (LINC) study. At the median age of 18 months, the children's behavior was assessed with the Child Behavior Checklist, using three composite behavior scales: externalizing problems, internalizing problems, and total problems. Linear regression analysis was performed, adjusting for maternal education and smoking by the partner. Children with higher BPA-BDPP, PBDPP, and tris(chloroethyl) phosphate (TCEP) house dust concentrations were found to have higher scores on the behavioral problems scales. A 10-fold increase in BPA-BDPP and PBDPP concentration was associated with a 4.1 and 2.6 point increase on the internalizing problems scale (respectively p=0.004 and p=0.042). Increased BPA-BDPP concentrations were associated with elevated scores on the externalizing problems scale and total behavioral problems scale (respectively 7.6 and 16 points increase per 10-fold BPA-BDPP concentration increase, p=0.015 and p=0.007). TCEP dust concentrations were associated with the externalizing problems scale (13 point increase per 10-fold TCEP concentration increase, p=0.043). This study showed the importance of investigating the health effects of exposure to organophosphate flame retardants. Further research on neurodevelopmental health effects of OPFR exposure is warranted.

Background Organophosphate esters (OPEs) are a class of flame retardants in common use. OPEs can easily leach from materials, resulting in human exposure. Increasing concentrations have been reported in human populations over the past decade. Recent studies have linked prenatal OPE exposure to hyperactivity and attention problems in children. Such behaviors are often found among children with attention-deficit hyperactivity disorder (ADHD), however, no study has investigated OPEs in relation to clinically assessed ADHD. Objective To evaluate prenatal exposure to OPEs as risk factors for clinically assessed ADHD using a case-cohort study nested within the Norwegian Mother, Father, and Child Cohort Study (MoBa). Methods We included in the case group 295 ADHD cases obtained via linkage with the Norwegian Patient Registry, and the sub-cohort group 555 children sampled at baseline, irrespective of their ADHD case status. Prenatal concentrations of OPE metabolites were measured in maternal urine collected at 17 weeks of gestation, and included diphenyl phosphate (DPHP), di-n-butyl phosphate (DNBP), bis(2-butoxyethyl) hydrogen phosphate (BBOEP), and bis(1,3-dichloro-2-propyl) phosphate (BDCIPP). We estimated risk ratios and the corresponding 95% confidence intervals [95% CI] using logistic regression, adjusting for season of urine collection, child sex, birth year, and maternal depression, education, and sum of urinary di(2-ethylhexyl) phthalate metabolites (∑DEHP) concentration during pregnancy. To assess the overall impact of simultaneously decreasing exposure to all chemical constituents of an OPE-phthalate mixture, quantile based g-computation was implemented. The mixture constituents included OPE and phthalate metabolites commonly detected in our study. In all models, we considered effect measure modification by child sex and polymorphisms in genes encoding paraoxonase 1 (PON1) and cytochrome P450 (P450) enzymes. Mediation analysis was conducted using thyroid function biomarkers estimated from maternal blood collected at 17 weeks of gestation. Results DPHP was detected in nearly all samples (97.2%), with a higher geometric mean among the case group (0.70 µg/L) as compared to the sub-cohort (0.52 µg/L). DNBP was commonly detected as well (93.8%), while BBOEP (52.9%) and BDCIPP (22.9%) were detected less frequently. A higher risk of ADHD was observed in children with greater than median exposure to DPHP during pregnancy (risk ratio: 1.38 [95% CI: 0.96, 1.99]), which was slightly higher among girls (2.04 [1.03, 4.02]) and children of mothers with PON1 Q192R genotype QR (1.69 [0.89, 3.19]) or PON1 Q192R genotype RR (4.59 [1.38, 15.29]). The relationship between DPHP and ADHD (total risk ratio: 1.34 [0.90, 2.02]) was partially mediated through total triiodothyronine to total thyroxine ratio (natural direct effect: 1.29 [0.87, 1.94]; natural indirect effect: 1.04 [1.00, 1.10]; 12.48% mediated). We also observed an elevated risk of ADHD in relation to BDCIPP detection during pregnancy (1.50 [0.98, 2.28]). We did not observe notable differences in ADHD by DNBP (0.88 [0.62, 1.26]) or BBOEP (1.03 [0.73, 1.46]) during pregnancy. Simultaneously decreasing all constituents of common-detect OPE-phthalate mixture, specifically DPHP, DNBP, and 6 phthalate metabolites, by a quartile resulted in an ADHD risk ratio of 0.68 [0.64, 0.72]. Conclusion Prenatal exposure to DPHP and BDCIPP may increase the risk of ADHD. For DPHP, we observed potential modification by child sex and maternal PON1 Q192R genotype and partial mediation through maternal thyroid hormone imbalance at 17 weeks gestation.

Recycling e-waste has been recognized as an important emission source of organophosphate triesters (tri-OPEs) and organophosphate diesters (di-OPEs), but the presence of di-OPEs in atmosphere has not been studied. Herein, tri-OPEs and di-OPEs in atmosphere of an e-waste dismantling park and surrounding area in South China were monitored for three consecutive years. Thirteen tri-OPEs and seven di-OPEs were identified. In 2017, 2018, and 2019, tri-OPE concentrations in e-waste dismantling park were 1.30 × 108, 4.60 × 106, and 4.01 × 107 pg/m3, while di-OPE concentrations were 1.14 × 103, 1.10 × 103, and 0.35 × 103 pg/m3, respectively, which were much higher than the surrounding area. Tri-OPEs and di-OPEs generated during e-waste dismantling affected surrounding area through diffusion. Triphenyl phosphate (TPhP) and diphenyl phosphate (DPhP) were the predominant congeners of tri-OPEs and di-OPEs, respectively. Additionally, TPhP concentration was extremely higher than other tri-OPEs, so TPhP could be used as an indicator of e-waste dismantling. Spearman correlation analysis showed significant correlations between DPhP and TPhP (R2 = 0.53, p

A novel nitrogen–phosphorus flame retardant (P–N FR) based on phosphonamidate, dimethyl N,N′-1,3-phenylenebis(P-methylphosphonamidate) (DMPMP), was successfully synthesized and its flame-retarding performances and thermal degradation were compared with those of other P–N FRs and a phosphorus-based FR such as resorcinol bis(diphenyl phosphate) (RDP). DMPMP was applied to acrylonitrile–butadiene–styrene (ABS) and ethylene–vinyl acetate (EVA) to investigate the factors governing the flame-retarding behaviors of P–N FRs which would make them efficient for noncharrable polymers. V-0 ratings were achieved at 20 wt % loading of DMPMP for ABS and at a much lesser amount of DMPMP loading (10 wt %) for EVA. Meanwhile, no rating and V-2 were achieved even at 20–30 wt % loading of other P–N FRs or RDP for ABS and EVA, respectively. The results from thermogravimetric analysis, Fourier transform infrared, and UL-94V indicated that DMPMP is a highly efficient FR and acts mainly in a gas-phase flame-retarding mode of action. The condensed phase of DMPMP also contributed to the flame retardancy property through −NH– groups which tendentiously generate a nitrogen–phosphorus-rich residue because of the intermolecular coupling transesterification reaction. These results demonstrated the assumption that DMPMP has a high P content and good hydrostability, which exhibits good flame retardancy for noncharrable polymers such as ABS and EVA.

In the present study we determined the concentrations and compositions of a suite of isopropylated and tert-butylated triarylphosphate ester (ITP and TBPP) isomers in house dust from the city of Guangzhou located in South China and the city of Carbondale in Midwestern United States. These two groups of organophosphate esters (OPE) are structurally analogous to triphenyl phosphate (TPHP), but have rarely been investigated for environmental occurrences and human exposure risks. The majority of target ITP and TBPP isomers were 100% detected in house dust from the two locations. Median concentrations of ΣITPs (including all ITP isomers) and ΣTBPPs (including all TBPP isomers) were 63.4 ng/g (range: 16.0–500 ng/g) and 35.4 ng/g (8.1–198 ng/g) in South China house dust, respectively, compared with 476 ng/g (140–1610 ng/g) for ΣITPs and 81.3 ng/g (35.2–800 ng/g) for ΣTBPPs in Midwestern U.S. dust. The profiles of ITP or TBPP isomers were similar between the two locations and were dominated by 2-isopropylphenyl diphenyl phosphate (2IPPDPP) and 4-tert-butylphenyl diphenyl phosphate (4tBPDPP), respectively. Although the levels of ΣITPs and ΣTBPPs were generally one order of magnitude lower than those of TPHP in the same dust samples, the broad occurrences of most of these isomers in house dust from the two locations likely suggest their wide applications in household consumer products. Estimated intakes of ΣITPs and ΣTBPPs via dust ingestion were generally three orders of magnitude lower than the reference dose proposed for TPHP. However, these emerging OPE chemicals merit continuous environmental surveillance, given their possible applications as specific commercial mixtures or as components/impurities in other flame retardant/plasticizer mixtures.

There is growing evidence that aryl organophosphate flame retardants (aryl-OPFRs) can disrupt lipid metabolism in animals. However, epidemiologic studies of this possible phenomenon are lacking. In...

Substitution of diethyl and diphenyl benzylic phosphates, Alk-CH(Ar1)OP(O)(OR)2 (R = Et, Ph; Alk = Me, Et, i-Pr; Ar1 = aryl), with the anions derived from Ar2CH2 (Ph2CH2,9H-xanthene and fluorene) and n-BuLi at –15 °C was studied. For phosphates with Me as an Alk, diethyl phosphates produced Me-CH(Ar1)CH(Ar2)2 (Ar1 = 4-halo-, 4-CN, 4-Me-, 2-Me, 2-Br-, 3-MeO-phenyl and 2-naphthyl). However, an unwanted substitution at the Et group competed with phosphates of Alk = Et- and i-Pr. Fortunately, the corresponding diphenyl phosphates cleanly underwent the desired substitution. Two enantioenriched phosphates, MeCH(Ph)OP(O)(OEt)2 and EtCH(Ph)OP(O)(OPh)2, proceeded with complete inversion of the stereochemistry.

Despite numerous studies on the contamination of organophosphate triesters (tri-OPEs) in indoor environments, organophosphate diesters (di-OPEs) have rarely been investigated. The present study aimed to investigate whether di-OPEs coexist with tri-OPEs in house dust collected from Guangzhou ( n = 30), South China and the city of Carbondale ( n = 17) located in the Midwestern United States (U.S.). Median concentrations of bis(2-butoxyethyl) phosphate (BBOEP), bis(1-chloro-2-propyl) phosphate (BCIPP), bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), bis(2-ethylhexyl) phosphate (BEHP), bis(2-methylphenyl phosphate) (BMPP), and diphenyl phosphate (DPHP) were determined to be 15.9, < LOQ, 33.6, 654, 9.5, and 605 ng/g in South China house dust, and 1580, 90.6, 234, 867, 4.0, and 6500 ng/g in Midwestern U.S. dust, respectively. The total concentrations of di-OPEs (referred to ΣdiOPEs) constituted an average of 22.9% and 21.3% of the total concentrations of tri-OPEs in dust from these two locations, respectively. Median concentration ratios of DPHP and BEHP to their respective tri-OPEs (i.e., TPHP and TEHP) were determined to be 1.1 and 1.0 in South China dust and 3.7 and 1.4 in Midwestern U.S. dust, respectively, indicating possible commercial applications for these two di-OPEs. Correlative analyses reveal chemical- and region-specific relationships between di-OPEs and their respective tri-OPEs, suggesting that the relative importance of different sources (e.g., direct commercial use, impurity in tri-OPE formulas, and tri-OPE degradation) could vary for different di-OPEs. Our findings demonstrate wide occurrences of di-OPEs in an indoor environment from the studied locations and raise concerns on human exposure to dust associated di-OPEs. Future studies are needed to explore more possible di-OPEs in indoor environments and elucidate their sources, human exposure pathways, and toxicokinetics.

The synergistic effect of mixed Cyanex 572 and n-octyl diphenyl phosphate for Th(IV) extraction from nitric acid solution has been investigated in this paper. The effect of acidity together with mole fraction of extractant on the synergistic effect was studied. Based on the obtained results, the maximal synergistic enhancement coefficient reaches 12.40 at a ratio of 1:2 of Cyanex 572 and n-octyl diphenyl phosphate. Under the experimental conditions, the phase separation performance, stripping property and selectivity of Th and REE in the mixed extraction system are better than those from individual Cyanex 572 or n-octyl diphenyl phosphate system. The synergistic extraction mechanism for Th(IV) in nitric acid medium is proposed as Th aq 4 + + HA 2 org + 2.5 B org + 3 NO 3 − aq ↔ K ex Th NO 3 3 HA 2 B 2.5 org + H aq + . The mixed extraction system is successfully used for the separation of Th(IV) and REE(III) from the industrial feed solution leached from ion-absorbed type rare earth mineral waste residue. Lower stripping acid, stronger extraction ability, better phase separation performance and selectivity provide the synergistic extraction system with good application prospects.

Brominated and phosphorus-based flame retardants (PFRs) were measured in foam and fabric samples from 18 newly marketed children’s car seats. The concentrations of two cyclic phosphonates {PMMMPs, 5-ethyl-2-methyl-2-oxido-1,3,2-dioxaphosphinan-5-yl)methyl methyl methylphosphonate and bis[(5-ethyl-2-methyl-1,3,2-dioxaphosphorinan-5-yl)methyl] methyl phosphonate p,p′-dioxide} were quantitatively measured for the first time in the North American environment and were much higher than those of other flame retardants. Median PMMMP concentrations were 73.6 μg/g, accounting on average for 52% of the total FR concentrations, indicating an intentional addition of PMMMPs during the manufacturing process of these car seats. Two other emerging PFRs [tris(2,4-di-Hi Katie,t-butylphenyl) phosphate (TDTBPP) and resorcinol bis(diphenyl phosphate) (RDP)] were detected for the first time in baby products at median levels of 1.11 and 6.15 μg/g, respectively. Other frequently detected PFRs included triethyl phosphate (TEP), tr...

Current environmental monitoring studies are generally confined to several target organophosphate esters (OPEs), and there is a lack of strategies for comprehensively screening all potential OPEs in environmental samples. Here, an effective and accurate strategy was developed for the target, suspect, and functional group-dependent screening of OPEs by the use of ultrahigh-performance liquid chromatography-Q Exactive hybrid quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS), and this strategy was applied for the analysis of n = 74 sediment samples (including 23 surface sediment samples and 51 sediment core samples) collected from Taihu Lake (eastern China) in 2019. In these analyzed samples, we successfully identified n = 35 OPEs, and 23 of them were reported in this region for the first time. In addition, this strategy also presented other interesting findings, i.e., (1) OPE concentrations decreased with increasing distance from the coast of the lake; (2) the newly identified 3-hydroxyphenyl diphenyl phosphate (meta-OH-TPHP) was not statistically significantly correlated with triphenyl phosphate (TPHP; r = 0.02494, p = 0.9101) but with resorcinol bis(diphenyl phosphate) (RDP) (r = 0.9271, p < 0.0001) and three other OPEs; and (3) the summed concentrations of aryl OPEs (∑arylOPEs) in sediment core samples exhibited significantly increasing trends as the depth decreased. Collectively, this study provided an effective strategy that was successfully applied for comprehensive screening of OPEs in the sediments of Taihu Lake, and this strategy could have promising potential to be extended to other environmental matrices or samples.

Over the course of the continual phase-outs of toxic halogenated flame retardants (HFRs), there has been an increasing demand for organophosphate esters (OPEs) in global FR markets. OPE-FRs have largely been identified as OP triesters, which have a basic chemical structure of O = P(OR)3. In addition to OP triesters, OPEs can refer to another class of related substances, namely, OP diesters that have a typical chemical structure of O = P(OR)2(OH)). OP diesters are known as biotic or abiotic degradation products of OP triesters. In recent years, environmental scientists have proven that OP diesters widely exist in a variety of environmental matrices and biotic samples around the world, implying the potential risks from OP diester exposure to biota and humans in the environment. Here, we have reviewed the scientific literature for studies involving OP diesters and up to the end of 2020. The aim of the present review is to assess the present understanding of the physicochemical properties, sources (industrial production and degradation), environmental occurrence of OP diesters, and adverse effects to exposed organisms. Based on the literature in the Web of Science core collection, we found that at least 23 OP diesters have been reported as contaminants in various environments or as degradation products of OP triesters. The physicochemical properties of OP diesters vary depending on their specific chemical structures. OP diesters containing halogen atoms and aryl groups seem to be more persistent (with greater estimated half-life (t1/2) values) in environmental matrices. There were multiple sources of OP diesters, including industrial production and biotic or abiotic degradation from OP triesters. Specifically, we found that ten OP diesters are produced somewhere in the world, and the total annual output was estimated to be 17,050 metric tons (this number is underestimated due to the limitation of the available information). In addition, the wide application of OP triesters worldwide makes the degradation of OP triesters another critical source of OP diesters to the environment and to organisms. Current monitoring studies have demonstrated that some OP diesters were detectable in the human body (via both blood and urine samples), indoor dust, wastewater, or sewage sludge worldwide. The highest concentrations of diphenyl phosphate (DPHP) in human urine have been reported as high as 727 ng/mL (children (aged 0–5 years) urine samples from Australia). In addition, adverse effects following direct or indirect exposure to 11 OP diesters in organisms (including animals, bacteria, and algae) have been reported, and the recorded adverse outcomes following exposure to OP diesters included developmental toxicity, alteration of gene expression, and disturbance of nuclear receptor activity. Biomonitoring studies regarding human samples have frequently reported statistically significant associations between the concentrations of OP diesters and markers of human health (mainly related to reproductive toxicity). Finally, on the basis of current knowledge on OP diesters, we propose prospects for related research directions in future studies.

This study aimed to investigate the occurrences of a suite of thirty-one organophosphate tri-esters (tri-OPEs) and six di-esters (di-OPEs) in house dust collected from Adelaide, South Australia. The results demonstrate ubiquitous presence of most OPEs in Adelaide house dust, with median concentration of 40,200 and 5260 ng/g dry weight for ∑tri-OPEs and ∑di-OPEs, respectively. A number of emerging OPEs with chemical structures resembling that of triphenyl phosphate (TPHP), including bisphenol A bis(diphenyl phosphate) (BPA-BDPP), cresyl diphenyl phosphate (CDP), isodecyl diphenyl phosphate (IDDPP), resorcinol-bis(diphenyl)- phosphate (RDP), as well as a suite of isopropylated or tert-butylated triarylphosphate ester isomers (ITPs or TBPPs), were frequently detected with combined levels surpassing that of TPHP. The investigated di-OPEs, predominated by DPHP, consisted of approximately 13% of the ∑tri-OPEs concentrations. Median concentration ratios of diphenyl phosphate (DPHP) and bis(2-ethylhexyl) phosphate (BEHP) to their respective tri-OPEs [i.e., TPHP and tris(2-ethylhexyl) phosphate (TEHP)] were determined to be 1.8 and 2.0, respectively, indicating possible commercial applications for these two di-OPEs. The estimated human intakes of dust-associated OPEs via dust ingestion and dermal contact were much lower than the reference doses. However, the risks of human exposure to OEPs may be complicated by quickly expanding family of OPEs containing various analogues and isomers as well as additional exposure pathways. Therefore, elucidation of human exposure to OPEs and associated risks requires extensive efforts in analytical, environmental, toxicological, and epidemiological investigations.

Levels of eleven organophosphate esters (OPEs) were measured in particle phase atmospheric samples collected at Bohai Sea and northern Yellow Sea in China. The concentration of ∑11OPEs in atmospheric particles ranged from 426 to 3933 pg/m3, with the mean concentration of 1412 pg/m3. Tris(1-chloro-2-propyl) phosphate (TCPP) and triphenyl-phosphine oxide (TPPO) were the most abundant OPE congeners measured, and the individual concentrations of trimethyl phosphate (TMP), tri-iso-butyl phosphate (TiBP), tri-n-butyl phosphate (TnBP), tris(1,3-dichloro-2-propyl) phosphate (TDCP), triphenyl phosphate (TPhP), 2-ethylhexyl diphenyl phosphate (EHDPP), TPPO and tri-m-cresyl phosphate (TMTP) in atmospheric particles above the Bohai Sea were higher than those above the northern Yellow Sea. The estimated atmospheric dry deposition fluxes ranged from 202 to 1869 ng/m2/day. Up to 18.3 ± 12.5 ton/year of OPEs can be loaded to the Bohai Sea.

As the number of chemicals developed and used by industry increases, the inherent limitations of traditional toxicology approaches become an unavoidable issue. To help meet the demand for toxicity evaluation, new methods, such as high-throughput toxicity screening, are currently being developed to permit rapid determination of toxic, molecular, and/or biochemical effects of a wide range of chemicals. In the present study, we demonstrate the utility of an avian in vitro toxicogenomics screening approach to determine the cytotoxic and transcriptomic effects of 10 organic flame retardants (OFRs) currently of international priority for ecological risk evaluation to prioritize and inform future toxicological studies. Hepatocytes from 2 avian species, chicken and double-crested cormorant, were prepared and exposed for 24 h to various concentrations (0-300 μM) of the following 10 OFRs: Chemical Abstracts Service registration numbers 29761-21-5, 56803-37-3 (p-tert-butylphenyl diphenyl phosphate [BPDP]), 65652-41-7, 68937-41-7 (phenol, isopropylated, phosphate [3:1] [IPPP]), 95906-11-9, 19186-97-1, 26040-51-7, 35948-25-5, 21850-44-2, and 25713-60-4. Cell viability, the 7-ethoxyresorufin-O-deethylase assay, and transcriptomic analysis using species-specific ToxChip polymerase chain reaction arrays were performed to evaluate the in vitro effect of these OFRs. Of the 10 OFRs assessed, BPDP and IPPP elicited the strongest cytotoxic and transcriptomic responses in both chicken and double-crested cormorant hepatocytes and are therefore recommended as priority candidates for further wildlife toxicological investigations. Environ Toxicol Chem 2018;37:3134-3144. © 2018 Crown in the right of Canada. Published by Wiley Periodicals Inc. on behalf of SETAC.

The present study investigated the occurrence of 20 organophosphate esters (OPEs) in house dust from 51 South China homes and the risks of human exposure to OPEs via two pathways: dust ingestion and hand-to-mouth contact. In addition to several traditional OPEs, five out of six novel OPEs, including bisphenol A bis(deiphenyl phosphate) (BPA-BDPP), t-butylphenyl diphenyl phosphate (BPDPP), cresyl diphenyl phosphate (CDP), isodecyl diphenyl phosphate (IDDPP), and resorcinol-bis(diphenyl)phosphate (RDP), were frequently detected in house dust (median concentration: 59.7-531 ng/g). Eight of the 20 target OPEs were frequently detected in hand wipes collected from adults and children ( n = 51 and 31, respectively), which in combination (referred to as Σ8OPEs) had a median mass of 76.9 and 58.9 ng, respectively. Increasing dust concentrations of Σ8OPEs or three individual substances among these eight OPEs, including tris(1-chloro-2-propyl) phosphate (TCIPP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP), and triphenyl phosphate (TPHP), were strongly associated with their levels in children's hand wipes ( p < 0.05 in all cases). By contrast, in adults' hand wipes only TPHP exhibited a marginally significant association with dust concentrations ( p = 0.04). Levels of Σ8OPEs in hand wipes from children, but not adults, were inversely influenced by hand washing frequency ( p = 0.002), while indoor temperature was inversely associated with hand wipe levels of Σ8OPEs from both children and adults ( p = 0.01 and 0.002, respectively). Exposure estimation suggests that hand-to-mouth contact represents another important pathway in addition to dust ingestion and that children are subjected to higher OPE exposure than adults.

Indoor environments provide sources of exposure to organophosphate flame retardants (PFRs), which are artificially synthesized fire-protecting agents used as additives in interior products. As public spaces, hotels are required to meet stricter fire-precaution criteria. As such, room attendants may be exposed to higher levels of PFRs. Our goal was to characterize the exposure of hotel room attendants to PFRs by measuring metabolites in their urine and the corresponding parent PFRs in dust and hand-wipes collected from 27 hotels located in Wuhan City, China. The exposure of the attendants was found to be omnipresent: urinary metabolites of PFRs, such as DPHP (diphenyl phosphate), BDCIPP (bis(1,3-dichloro-2-propyl) phosphate), and DoCP (di-o-cresyl phosphate) & DpCP (di-p-cresyl phosphate) were detected with high frequency (87%, 79% and 87%, respectively). We observed that metabolites in post-shift urine were consistently present at higher levels than those in the first morning voids (p < 0.05 for BDCIPP and DPHP). Regarding external exposure, 10 PFRs were determined in both dust samples and hand-wipes, with TCIPP (tris(2-chloroisopropyl) phosphate) being the most abundant compound in both matrices. The levels of PFRs in hand-wipes and dust samples were not correlated. PFRs in dust and their corresponding urinary metabolites were not significantly correlated, while a moderate significant correlation of TDCIPP (tris(1,3-dichloro-2-propyl) phosphate) in hand-wipes and its urinary metabolite, BDCIPP, was observed in both morning void samples (p = 0.01) and post-shift urine (p = 0.002). Moreover, we found that participants from high-rise buildings (defined as > 7 stories) had significantly higher BDCIPP and DPHP concentrations than those from low-rise buildings. A possible reason is that high-rise buildings may use high-grade fireproof building materials to meet stricter fire restrictions. Overall, these results indicate that PFRs exposure in hotels is a contributor to the personal exposure of hotel room attendants. (C) 2018 Elsevier Ltd. All rights reserved.

Organophosphate flame retardants (PFRs) and bisphenol A (BPA) were measured in indoor dust and PM2.5 samples from nine kindergartens and two primary schools in Hong Kong. The average levels of PM2.5 ranged from 4.0E+03 ng/m3 to 1.5E+04 ng/m3. Average levels of PFRs (from 1.5 ng/m3 to 20 ng/m3 in PM2.5; from 8.0E−02 μg/g dw to 2.4 μg/g dw in dust) and BPA (from 6.4E−01 ng/m3 to 1.0 ng/m3 in PM2.5; from 1.0E−02 μg/g dw to 2.0E−01 μg/g dw in dust) were detected in most of the sampling sites. Tri-(2-Chloroethyl) phosphate (TCEP), tris(1,3-Dichloro-2-propyl) phosphate (TDCP), tris-(chloroisopropyl) phosphate (TCPP), and triphenyl phosphate (TPHP) were present in low levels in PM2.5 with medians of 16, 14, 8.7, and 3.2 ng/m3, respectively. In dust, the medians were 1.5E−01, 5.5E−02, 5.9E−01, 8.6E−01, and 8.5E−02 μg/g dw for TCEP, TCPP, TDCPP, TPHP, and 2-ethylhexyl diphenyl phosphate, respectively. The medians of BPA were 6.4E−01 ng/m3 and 7.4E−02 μg/g dw for PM2.5 and dust, respectively. A positive correlation was found between indoor PM2.5 and dust in the levels of TCEP (r = 0.85; p = .05). In the individual classroom in this survey, the predominant PFRs were similar, that is, TDCP and TCEP in indoor PM2.5 while TPHP and TDCP in dust. TPHP and TCEP in primary schools were obviously lower than those in kindergartens. The estimated daily intakes via PM2.5 and dust for all selected PFRs ranged from 1.3E−4 μg/kg/d to 2.0E−02 μg/kg/d, and the value of less than the detection limit at 3.5E−4 μg/kg/d was found for BPA. The EDI values of TPHP in dust non-dietary intake fraction were higher than those in the others. Calculated hazard indices (EDI/RfD) ranged from 4.8E−06 and 5.5E−03, showing that PFRs and BPA in PM2.5 and dust presented no health risks to children.

Organophosphate esters (OPEs) are widely used in household products as flame retardants or plasticizers and have become ubiquitous pollutants in environmental media. However, little is known about OPE metabolites in humans, especially in children. In this study, eight OPE metabolites were measured in 411 urine samples collected from 6 to 14-year-old children in South China. Bis(2-chloroethyl) phosphate (BCEP), bis(1-chloro-2-propyl) phosphate (BCIPP) and diphenyl phosphate (DPHP) were the dominant OPE metabolites, and their median concentrations were 1.04, 0.15 and 0.28 μg/L, respectively. The levels of urinary OPE metabolites in the present study were much lower than those in participants from other countries, with the exception of BCEP, suggesting widespread exposure to tris(2-chlorethyl) phosphate (TCEP, the parent chemical of BCEP) in South China. No significant difference in the concentrations of any of the OPE metabolites was observed between males and females (p > .05). Significant negative correlations were observed between age and BCEP, BCIPP, bis(1,3-dichloro-2-propyl) phosphate (BDCIPP), di-o-cresyl phosphate (DoCP) and di-p-cresyl phosphate (DpCP) (DCP), or DPHP (p

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.

Phosphate flame retardants (PFRs) are ubiquitous chemicals in the indoor environment. Diphenyl phosphate (DPHP) is a major metabolite and a common biomarker of aryl-PFRs. Since it is used as a chemical additive and it is a common impurity of aryl-PFRs as well as a degradation product, its presence in indoor dust as an additional source of exposure should not be easily ruled out. In this study, DPHP (and TPHP) are measured in indoor dust in samples collected in Spain and in the Netherlands (n=80). Additionally, the presence of other emerging aryl-PFRs was monitored by target screening. TPHP and DPHP were present in all samples in the ranges 169–142,459ng/g and 106–79,661ng/g, respectively. DPHP concentrations were strongly correlated to the TPHP levels (r=0.90, p