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The penetration of organophosphate triesters (tri-OPEs) and diesters (di-OPEs) across the blood-brain barrier and their influencing factors remain unclear in humans. In this study, 21 tri-OPEs and 8 di-OPEs were measured in 288 paired serum and cerebrospinal fluid (CSF) samples collected in Jinan, China. Six tri-OPEs were frequently detected in both serum and CSF, with median concentrations ranging from 0.062 to 1.62 and 0.042-1.11 ng/mL, respectively. Their penetration efficiencies across the blood-CSF barrier (BCSFB) (

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The production and application of organophosphate esters (OPEs) have dramatically increased in recent years due to their use as a replacement for brominated flame retardants. In this study, 13 OPEs (Σ13OPEs) were analyzed in indoor air samples from kitchens and living rooms in 14 residential homes in Beijing, China. The concentrations of Σ13OPEs in kitchen air samples (mean: 13 ng/m3) were significantly (p

Human exposure to OPEs is pervasive and should be of great concern due to associations with adverse health effects, especially in susceptible populations. In this study, body burdens and exposure pathways of OPEs were investigated for 76 healthy elderly people in Jinan, China based on the measured OPE and metabolite concentrations in human bio-samples (whole blood and urine) and paired environmental matrices (air and dust), as well as food frequency questionnaire. Eight of 16 OPEs and 5 of 11 metabolites were detected in > 50% of whole blood and urine samples, respectively. Tri(1-chloro-2-propyl) phosphate (TCIPP), tris(2-chloroethyl) phosphate (TCEP), tri-phenyl phosphate (TPHP), and 2-ethylhexyl di-phenyl phosphate (EHDPP) were frequently detected and abundant in whole blood, while their corresponding metabolites were detected at low frequencies or levels in urine. The reduced metabolic and/or excretory capacity of elderly people may be an important reason, implying a higher health risk to them. Fourteen OPEs had over 50% detection frequencies in indoor air and dust, while 6 di-esters in indoor dust. Tris(2-ethylhexyl) phosphate (TEHP) in indoor dust and tri-n-butyl phosphate (TnBP) in indoor air were positively correlated with paired levels in blood but not with their metabolites (BEHP and DnBP) in urine. Combined with the direct intakes of BEHP and DBP from dust, blood is indicated as more suitable biomarker for TEHP and TnBP exposure. High consumption frequencies of several foods were associated with higher blood concentrations of three OPEs and urinary levels of four di-OPEs, indicating the importance of dietary exposure pathway. Estimated daily total intakes of OPEs via inhalation, dust ingestion, and dermal absorption ranged from 2.78 to 42.0 ng/kg bw/day, which were far less than the reference dosage values. Further studies were warranted to explore the potential health effects of OPE exposure in the elderly populations.

The ubiquity of organophosphate esters (OPEs) in various environmental matrices inevitably pose human exposure risks. Numerous studies have investigated human exposure pathways to OPEs, including air inhalation, dust ingestion, dermal contact, and dietary and drinking water intake, and have indicated that indoor dust and indoor air routes are frequently the two main human exposure pathways. This article reviews the literature on OPE contamination in indoor air and dust from various microenvironments and on OPE particle size distributions and bioavailability in dust conducted over the past 10 years. Ways in which sampling strategies are related to the uncertainty of exposure assessment results and comparability among different studies in terms of sampling tools, sampling sites, and sample types are addressed. Also, the associations of OPEs in indoor dust/air with human biological samples were summarized. Studies on two emerging matrices, hand wipes and silicone wristbands, are demonstrated to be more comprehensive and accurate in reflecting personal human exposure to OPEs in microenvironments and are summarized. Given the direct application of some diester OPEs (di-OPEs) in numerous products, research on their existence in indoor dust and food and on their effects on human urine are also discussed. Finally, related research trends and avenues for future research are prospected.

Organophosphorus flame retardants (OPFRs) have been detected ubiquitously in the air and water worldwide, but no study has focused on their air-water exchange process. Here, we investigated the concentrations, distributions, and seasonal variations of OPFRs in the coastal air and water of Dalian, China. The total concentrations of 10 OPFRs in the air based on passive air sampling ranged from 0.50 to 20.0 ng/m3, while the concentrations of OPFRs in the water dissolved phase ranged from 48.3 to 681 ng/L. Relatively high concentrations were mainly discovered near the industry areas or river estuaries, suggesting that point sources along the coastline may significantly influence the local OPFR concentrations. Tris(2-chloroisopropyl) phosphate (TCIPP) was the most dominant congener followed by tris(2-chloroethyl) phosphate (TCEP), which was consistent with their high production and persistence. The air-water gaseous exchanges of OPFRs were estimated for the first time according to their concentrations in gaseous and dissolved phases. Generally, the gaseous exchange fluxes varied with sampling site and period. TCIPP showed the highest gaseous deposition flux of −395 ± 1211 ng/(m2 d), while TCEP showed the highest emission flux of 1414 ± 2093 ng/(m2 d). The dry deposition fluxes of OPFRs (0.05–822 ng/(m2 d)) were also calculated based on their particle fractions in the air. The result suggested that both gaseous exchange and particle deposition processes significantly influenced the air-water transport of OPFRs in this area.

In this study, polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and dechlorane plus (DPs) were analyzed in seven categories of building and decoration materials. The total concentrations of analyzed FRs ranged from 1.19 ng/g (diatomite powder) to 9532 ng/g (expanded polystyrene panel). Relatively high concentrations were detected in foam samples and PVC materials, followed by sealing materials, boards, wallpaper, paints, and wall decoration powders. BDE209 was the most detected compound with the highest concentrations in almost all materials, followed by decabromodiphenyl ethane (DBDPE), which was consistent with their productions and consumptions in China. The estimated PBDE concentrations in air and dust based on material concentration and emission rate were comparable with those detected in real samples. Adult and infant exposures via inhalation and dust ingestion were assessed. The estimated exposures to BDE209 via dust ingestion were 1.36 and 0.12 ng/(kg bw d), which were 19- and 4-fold higher than those via inhalation for infants and adults, respectively. This suggested that dust ingestion was a significant pathway of human BDE209 exposure, especially for infants. For the other PBDE congeners (∑7PBDEs), the estimated exposures via inhalation were 2.60 and 1.32 ng/(kg bw d) for infants and adults, respectively. Despite the low estimated human exposures to PBDEs compared to the oral reference doses, the exposure associated with building and decoration materials still requires more attention because of the potential risks from other exposure pathways and undetected FRs in those materials.

Organophosphorus flame retardants (OPFRs) have been increasingly used in various building and decoration materials to fulfill fire safety standards since the phasing out of polybrominated diphenyl ethers. We determined OPFR concentrations in the most commonly used building and decoration materials available in local markets and online in China. The OPFR concentrations varied significantly, from 14.78 ng/g (putty powder) to 9649000 ng/g (expanded polystyrene panel (EPS)). Relatively high concentrations of OPFRs were found in foam samples, followed by nonwoven and polyvinyl chloride (PVC) wallpaper, PVC pipes, sealing materials, boards, and paints. Low concentrations were found mostly in wall decoration powders, suggesting that no OPFRs had been added to these powders. Tris(1-chloro-2-propyl) phosphate and tris(1,3-dichloro-2-propyl) phosphate were the most detected halogenated OPFRs, while tri-n-butyl phosphate and tris(2-butoxyethyl) phosphate were the dominant nonhalogenated OPFRs, implying that they are commonly used in building and decoration materials. The estimated OPFR burden in interior decoration using nonwoven wallpaper was 330- and 2110-fold higher than that using latex paint and diatomite, respectively. The emission periods of OPFRs from nonwoven and PVC wallpaper may be greater than 13 years. We estimated that the total burden of OPFRs for decoration using wallpaper in newly decorated houses in China is ∼63 t/y. Significantly higher concentrations of OPFRs in interior decoration materials, especially nonwoven wallpaper, pose potential health risks to the people using the buildings.

Although organophosphate diester (di-OPE) metabolites in urine are usually used to assess human exposure to organophosphate esters (OPEs), whether they can reflect human exposure to all OPEs with great differences in chemical structures and properties is still currently unclear. In this study, we detected sixteen OPEs and ten di-OPEs in 52 paired whole blood, serum, and urine samples collected in Beijing, China to investigate the correlations between different compounds and matrices, thus providing proper biomarkers of human exposure to OPEs. The order of the median concentrations of ∑OPEs was whole blood (8.63 ng/mL) > serum (5.71 ng/mL) > urine (0.396 ng/mL), while those of ∑di-OPEs followed the order of urine (16.6 ng/mL) > whole blood (5.97 ng/mL) > serum (3.70 ng/mL). Ethylhexyl diphenyl phosphate (EHDPP) and cresyl diphenyl phosphate (CDPP) were the dominant OPEs in both whole blood and serum samples and were significantly correlated between these two matrices. The distribution of OPEs in human blood was evaluated according to serum-to-whole blood concentration ratios (S:WB ratios). The median S:WB ratios of triethyl phosphate (TEP), tri-n-butyl phosphate (TnBP), bisphenol-A bis(diphenyl phosphate) (BABP), EHDPP, and CDPP were lower than 1, indicating that these OPEs preferred to accumulated in blood cells rather than in serum/plasma. Bis(2-ethylhexyl) phosphate (BEHP) was the major di-OPEs and was detected in almost all whole blood, serum and urine samples. The median whole blood: urine (WB:UR) ratios of di-OPEs were significantly and positively correlated with their logKow values, indicating that di-OPEs with low hydrophobicity were prone to excretion via urine. Based on the relationships between OPEs and di-OPEs in these matrices, the parent OPEs in whole blood can be recommended for use as alternative biomarkers of aryl-OPEs exposure in future human biomonitoring studies, in addition to metabolites in urine.

The atmospheric deposition fluxes of polybrominated diphenyl ethers (PBDEs) and Dechlorane Plus (DPs) in Dongjiang River Basin of the Pearl River Delta in South China were investigated during winter and summer, respectively. The total deposition fluxes varied from 4.74 to 27.0 ng/m2/day for PBDEs and 8.77 to 206 ng/m2/day for DPs, respectively. The fractions of anti-DP to the total DPs (f anti) varied from 0.28 to 0.63 (mean = 0.43 ± 0.06), i.e., generally lower than those in commercial products, which might be attributed to the different environmental fates of the two isomers. Significant seasonal and spatial variations of PBDEs and DPs were observed. The deposition fluxes in summer were generally higher than those in winter, which may be due to the relatively high temperature and rainfall in summer under the influence of prevailing subtropical monsoon climate. Moreover, high deposition fluxes of PBDEs and DPs in urban areas and significant urban/rural gradient implied that local industrial activities in the urban areas were primary sources, which were further confirmed by the results of principal component analysis. The highest deposition of PBDE and DP fluxes was found at different sampling sites, suggesting PBDEs and DPs may be derived from different industries or products.

The diurnal atmospheric concentrations of polychlorinated biphenyls (PCBs) were investigated at an abandoned e-waste recycling site in South China during winter and summer. Total PCB concentrations during winter and summer were 27.6–212 and 368–1704 pg/m 3 in the particulate phase and 270–697 and 3000–15,500 pg/m 3 in the gaseous phase, respectively. Both gaseous and particulate PCB concentrations and compositions exhibited significant difference between winter and summer samples, but no diurnal variations during the measurement period. The correlation analysis between PCB concentrations and meteorological conditions, including atmospheric temperature, humidity, and mixing layer height, suggested that the seasonal variability of atmospheric PCB concentrations was strongly temperature-dependent, while the diurnal variability was probably source-dependent. The temperature-driven variations can also be proved by the significant linear correlation between ln P and 1/T in the Clausius-Clapeyron plot. Although government has implemented controls to reduce e-waste pollution, both the relatively high concentrations of PCBs and the diurnal variation in the air suggested that emissions from occasional e-waste recycling activities may still exist in this recycling area. These results underline the importance of continuing e-waste recycling site management long after abandonment.