Uptake, translocation, and metabolism of organophosphate esters (OPEs) in plants and health perspective for human: A review.

Plant uptake, accumulation, and transformation of organophosphate esters (OPEs) play vital roles in their geochemical cycles and exposure risks. Here we reviewed the recent research advances in OPEs in plants. The mean OPE concentrations based on dry/wet/lipid weight varied in 4.80-3,620/0.287-26.8/12,000-315,000 ng g-1 in field plants, and generally showed positive correlations with those in plant habitats. OPEs with short-chain substituents and high hydrophilicity, particularly the commonly used chlorinated OPEs, showed dominance in most plant samples, whereas some tree barks, fruits, seeds, and roots demonstrated dominance of hydrophobic OPEs. Both hydrophilic and hydrophobic OPEs can enter plants via root and foliar uptake, and the former pathway is mainly passively mediated by various membrane proteins. After entry, different OPEs undergo diverse subcellular distributions and acropetal/basipetal/intergenerational translocations, depending on their physicochemical properties. Hydrophilic OPEs mainly exist in cell sap and show strong transferability, hydrophobic OPEs demonstrate dominant distributions in cell wall and limited migrations owing to the interception of Casparian strips and cell wall. Additionally, plant species, transpiration capacity, growth stages, commensal microorganisms, and habitats also affect OPE uptake and transfer in plants. OPE metabolites derived from various Phase I transformations and Phase II conjugations are increasingly identified in plants, and hydrolysis and hydroxylation are the most common metabolic processes. The metabolisms and products of OPEs are closely associated with their structures and degradation resistance and plant species. In contrast, plant-derived food consumption contributes considerably to the total dietary intakes of OPEs by human, particularly the cereals, and merits specifical attention. Based on the current research limitations, we proposed the research perspectives regarding OPEs in plants, with the emphases on their behavior and fate in field plants, interactions with plant-related microorganisms, multiple uptake pathways and mechanisms, and comprehensive screening analysis and risk evaluation.

Do the same chlorinated organophosphorus flame retardants that cause cytotoxicity and DNA damage share the same pathway?

Organophosphorus flame retardants (OPFRs) have been frequently detected with relatively high concentrations in various environmental media and are considered emerging environmental pollutants. However, their biological effect and underlying mechanism is still unclear, and whether chlorinated OPFRs (Cl-OPFRs) cause adverse outcomes with the same molecular initial events or share the same key events (KEs) remains unknown. In this study, in vitro bioassays were conducted to analyze the cytotoxicity, mitochondrial impairment, DNA damage and molecular mechanisms of two Cl-OPFRs. The results showed that these two Cl-OPFRs, which have similar structures, induced severe cellular and molecular damages via different underlying mechanisms. Both tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propyl) (TCPP) induced oxidative stress-mediated mitochondrial impairment and DNA damage, as shown by the overproduction of intracellular reactive oxygen species (ROS) and mitochondrial superoxide. Furthermore, the DNA damage caused by TCPP resulted in p53/p21-mediated cell cycle arrest, as evidenced by flow cytometry and real-time PCR. At the cellular and molecular levels, TCPP increased the sub-G1 apoptotic peak and upregulated the p53/Bax apoptosis pathway, possibly resulted in apoptosis associated with its stronger cytotoxicity. Although structurally similar to TCPP, TCEP did not induce mitochondrial impairment and DNA damage by the same KEs. These results provide insight into the toxicity of Cl-OPFRs with similar structures but different mechanisms, which is of great significance for constructing adverse outcome pathways or determining intermediate KEs.

Computational Insights into Cyclodextrin Inclusion Complexes with the Organophosphorus Flame Retardant DOPO.

Cyclodextrins (CDs) were used as green char promoters in the formulation of organophosphorus flame retardants (OPFRs) for polymeric materials, and they could reduce the amount of usage of OPFRs and their release into the environment by forming [host:guest] inclusion complexes with them. Here, we report a systematic study on the inclusion complexes of natural CDs (α-, ß-, and γ-CD) with a representative OPFR of DOPO using computational methods of molecular docking, molecular dynamics (MD) simulations, and quantum mechanical (QM) calculations. The binding modes and energetics of [host:guest] inclusion complexes were analyzed in details. α-CD was not able to form a complete inclusion complex with DOPO, and the center of mass distance [host:guest] distance amounted to 4-5 Å. ß-CD and γ-CD allowed for a deep insertion of DOPO into their hydrophobic cavities, and DOPO was able to frequently change its orientation within the γ-CD cavity. The energy decomposition analysis based on the dispersion-corrected density functional theory (sobEDAw) indicated that electrostatic, orbital, and dispersion contributions favored [host:guest] complexation, while the exchange-repulsion term showed the opposite. This work provides an in-depth understanding of using CD inclusion complexes in OPFRs formulations.

The investigation of the toxicity of organophosphorus flame retardants (OPFRs) by using in silico toxicity prediction platform ProTox- 3.0.

From the past to the present, many chemicals have been used for the purpose of flame retardant. Due to PBDEs' (Polybrominated diphenyl ether) lipophilic and accumulative properties, some of them are banned from the market. As an alternative to these chemicals, OPFRs (organophosphorus flame retardants) have started to be used as flame retardants. In this article, acute toxicity profiles, mutagenicity, carcinogenicity, blood-brain barrier permeability, ecotoxicity and nutritional toxicity as also AHR, ER affinity and MMP, aromatase affinity, CYP2C9, CYP3A4 interaction of the of 16 different compounds of the OPFRs were investigated using a computational toxicology method; ProTox- 3.0. According to our results, eight compounds were found to be active in terms of carcinogenic effect, whereas two compounds were found to be active for mutagenicity. On the other hand, all compounds were found to be active in terms of blood-barrier permeability. Fourteen compounds and four compounds are found to have ecotoxic and nutritional toxic potency, respectively. Eight compounds were determined as active to AhR, and four chemicals were found to be active in Estrogen Receptor alpha. Eight chemicals were found to be active in terms of mitochondrial membrane potency. Lastly, three chemicals were found to be active in aromatase enzymes. In terms of CYP interaction potencies, eight compounds were found to be active in both CYP2C9 and CYP3A4. This research provided novel insights into the potential toxic effects of OPFRs. However, further studies are needed to evaluate their toxicity. Moreover, these findings lay the groundwork for in vitro and in vivo toxicity research.

Biotransformation of Organophosphate Esters by Rice and Rhizosphere Microbiome: Multiple Metabolic Pathways, Mechanism, and Toxicity Assessment.

The biotransformation behavior and toxicity of organophosphate esters (OPEs) in rice and rhizosphere microbiomes were comprehensively studied by hydroponic experiments. OPEs with lower hydrophobicity were liable to be translocated acropetally, and rhizosphere microbiome could reduce the uptake and translocation of OPEs in rice tissues. New metabolites were successfully identified in rice and rhizosphere microbiome, including hydrolysis, hydroxylated, methylated, and glutathione-, glucuronide-, and sulfate-conjugated products. Rhizobacteria and plants could cooperate to form a complex ecological interaction web for OPE elimination. Furthermore, active members of the rhizosphere microbiome during OPE degradation were revealed and the metagenomic analysis indicated that most of these active populations contained OPE-degrading genes. The results of metabolomics analyses for phytotoxicity assessment implied that several key function metabolic pathways of the rice plant were found perturbed by metabolites, such as diphenyl phosphate and monophenyl phosphate. In addition, the involved metabolism mechanisms, such as the carbohydrate metabolism, amino acid metabolism and synthesis, and nucleotide metabolism in Escherichia coli, were significantly altered after exposure to the products mixture of OPEs generated by rhizosphere microbiome. This work for the first time gives a comprehensive understanding of the entire metabolism of OPEs in plants and associated microbiome, and provides support for the ongoing risk assessment of emerging contaminants and, most critically, their transformation products.

Regional Distribution of Atmospheric Organophosphate Tri-/Diesters in the Pearl River Delta: Possible Emission, Photo-degradation, and Atmospheric Transportation.

The regional characteristics of atmospheric organophosphate triesters (OPEs) and organophosphate diesters (Di-OPs) in the Pearl River Delta (PRD) were investigated by passive air samplers mounting quartz fiber filters. The analytes were found on a regional scale. Atmospheric OPEs, semi-quantified using sampling rates of particulate-bonded PAHs, were in the range of 537-2852 pg/m3 in spring and in the range of 106-2055 pg/m3 in summer, with tris(2-chloroethyl)phosphate (TCEP) and tris(2-chloroisopropyl)phosphate as the main components. While atmospheric Di-OPs were semi-quantified using sampling rates of SO42-, in the range of 22.5-5576 pg/m3 in spring and in the range of 66.9-1019 pg/m3 in summer, with di-n-butyl phosphate and diphenyl phosphate (DPHP) being the main Di-OPs. Our results indicated that OPEs were mainly distributed in the central part of the region, which might be ascribed to the distribution of industry related to OPE-containing products. In contrast, Di-OPs were scattered in the PRD, suggesting local emission from their direct industrial application. Significantly lower levels of TCEP, triphenyl phosphate (TPHP), and DPHP were detected in summer than in spring, implying that these compounds might be partitioned off particles as the temperature increased and due to possible photo-transformation of TPHP and DPHP. The results also suggested the long-distance atmospheric transportation potential of Di-OPs.

Partitioning behavior-oriented health risk assessment on internal organophosphorus flame retardants exposure.

Though the partitioning behavior of organophosphorus flame retardants (OPFRs) has been recognized in vitro incubation assay, health risk assessment on those internal exposure with or without partitioning indexes in human blood is still unclear. In this study, nine commonly used OPFRs were quantified in 96 pairs of plasma and blood cell samples from Chinese volunteers. Non-carcinogenic and carcinogenic risk (CR) assessment building upon two distinct scenarios were conducted and compared. The dominant OPFRs in both plasma and blood cells were TBEP, TBP and TPHP. TCEP was the most enriched compound in plasma with Fplasma nearly to 1.0 (0.92), followed by TCPP, TBEP, TPHP, TBP and TEHP (from 0.61 to 0.76). The partitioning behavior of TCP in plasma was equivalent to blood cells with Fplasma at 0.50. When fully considered the Fplasma, the estimated average daily intake (DI) of ∑OPFRs (638.44 ng/kg BW/day) reached nearly 1.48-fold higher than the conventional calculation (dividing the concentration of plasma (Cplasma) by a factor of 2.0). Accordingly, we found the average hazard quotation (index) of TBP, TPHP and ∑OPFRs was underrated 1.50-fold when neglected the partitioning behaviors. Notably, the average CR of TCEP exceeded 10-6 at the highest concentration (1.19 × 10-6 ng/mL in plasma) only when the Fplasma was introduced. These data conjointly demonstrated that most of the DI levels and the corresponding risk index of OPFRs would be underestimated without factoring Fplasma into calculation, especially for those of low plasma partitioning. To our best knowledge, this study initially uncovered the gap between introducing Fplasma and dividing Cplasma by 2.0 during health risk assessment on internal OPFRs exposure.

Organophosphorus flame retardants and their metabolites in paired human blood and urine.

Organophosphorus flame retardants (OPFRs) have been shown to be carcinogenic, neurotoxic, and endocrine disruptive, so it is important to understand the levels of OPFRs in human body as well as the modes of external exposure. In this study, we investigated the levels of 13 OPFRs and 7 phosphodiester metabolites in paired human blood and urine, as well as the influencing factors (region, age and gender), and studied the relationship between OPFRs and oxidative stress by urinary metabolites. We found that the concentrations of triphenyl phosphate (TPhP) and tris-(2-ethylhexyl) phosphate (TEHP) in the blood of urban populations were higher than those of rural populations, and that younger populations suffered higher TPhP and 2-ethylhexyl diphenyl phosphate (EHDPP) exposures than older populations. In addition, we found that tris-(2-chloroethyl) phosphate (TCEP), tributyl phosphate (TnBP), TPhP and EHDPP exposure induced oxidative stress. The results of the internal load principal component analysis indicated that dust ingestion, skin exposure, respiration and dietary intake may be the most important sources of TCEP, tris(2-butoxyethyl) phosphate (TBOEP), tri(2-chloroisopropyl) phosphate (TCIPP) and TEHP, respectively, and dust ingestion and skin exposure may be the main sources of TPhP for humans.

Metagenomic insights into the mechanisms of triphenyl phosphate degradation by bioaugmentation with Sphingopyxis sp. GY.

Biodegradation of triphenyl phosphate (TPHP) by Sphingopyxis sp. GY was investigated, and results demonstrated that TPHP could be completely degraded in 36 h with intracellular enzymes playing a leading role. This study, for the first time, systematically explores the effects of the typical brominated flame retardants, organophosphorus flame retardants, and heavy metals on TPHP degradation. Our findings reveal that TCPs, BDE-47, HBCD, Cd and Cu exhibit inhibitory effects on TPHP degradation. The hydrolysis-, hydroxylated-, monoglucosylated-, methylated products and glutathione (GSH) conjugated derivative were identified and new degradation pathway of TPHP mediated by microorganism was proposed. Moreover, toxicity evaluation experiments indicate a significant reduction in toxicity following treatment with Sphingopyxis sp. GY. To evaluate its potential for environmental remediation, we conducted bioaugmentation experiments using Sphingopyxis sp. GY in a TPHP contaminated water-sediment system, which resulted in excellent remediation efficacy. Twelve intermediate products were detected in the water-sediment system, including the observation of the glutathione (GSH) conjugated derivative, monoglucosylated product, (OH)2-DPHP and CH3-O-DPHP for the first time in microorganism-mediated TPHP transformation. We further identify the active microbial members involved in TPHP degradation within the water-sediment system using metagenomic analysis. Notably, most of these members were found to possess genes related to TPHP degradation. These findings highlight the significant reduction of TPHP achieved through beneficial interactions and cooperation established between the introduced Sphingopyxis sp. GY and the indigenous microbial populations stimulated by the introduced bacteria. Thus, our study provides valuable insights into the mechanisms, co-existed pollutants, transformation pathways, and remediation potential associated with TPHP biodegradation, paving the way for future research and applications in environmental remediation strategies.

Organophosphate esters in inert landfill soil: A case study.

Organophosphate esters (OPEs) used as flame retardants and plasticizers are additives in building and construction materials, decorations, furniture, electronic equipment, among other applications. The presence of materials containing these substances in construction and demolition waste (CDW) from weak waste management practices can result in environmental contamination. In this study, OPEs' presence in soil samples collected from a CDW landfill in Brazil was evaluated. Soil samples were collected in areas adjacent to CDW from an inert landfill, and the samples were analysed by gas chromatography coupled to mass spectrometry. The OPEs were detected in all soil samples at quantifiable concentrations ranging from 21 to 251 ng g-1, and detected compounds were tris(phenyl) phosphate, tris(2-butoxyethyl) phosphate, tris(1,3-dichloroisopropyl) phosphate, tris(2-chloroisopropyl) phosphate and 2-ethylhexyl diphenyl phosphate. The presence of these compounds in a CDW landfill is probably due to the lack of control of the materials sent to and deposited in the landfill, which, results in part from the lack of sampling and screening systems that can help identify the presence of contaminants in the CDW waste stream. This is partially due to OPEs not being considered controlled compounds under current regulations, thus screening or separation for handling of OPEs at construction and demolition work sites is rare to non-existent. The data generated in this study reveals the need for improving CDW management to minimize, if not eliminate, environmental contamination by OPEs.

A comprehensive analysis-based study of triphenyl phosphate-environmental explanation of glioma progression.

As BFRs have gradually been banned recently, organophosphorus flame retardants (OPFRs) have been manufactured and used in their place. Although OPFRs are considered the better alternatives to BFRs, many studies have discovered that OPFRs may be associated with various cancers, including prostate cancer, bladder cancer, hepatocellular carcinoma, and colorectal cancer. However, few studies have examined the relationship between OPFRs and gliomas. This study investigated the relationship between triphenyl phosphate (TPP) and glioma using bioinformatics analysis approaches. The comparative toxicogenomics database (CTD) and The Cancer Genome Atlas (TCGA) databases were accessed for TPP-related genes and gene expression data from glioma patients. The Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses show that TPP might be closely related to many pathways. Further, the analysis of protein-protein interactions revealed strong intrinsic relationships between TPP-related genes. In addition, the TPP-based prognostic prediction model demonstrated promising results in predicting the prognosis of patients with gliomas. Several TPP-related genes were closely related to glioma patients' overall survival rates. The proliferation and migration abilities of glioma cells were further demonstrated to be significantly enhanced by TPP. In a bioinformatics analysis, we also discovered that melatonin is highly correlated with the presence of TPP and gliomas. According to the cell proliferation and migration assays, exposure to melatonin and TPP inhibited the ability of glioma cells to invade compared with the TPP group.

Biphasic effects of typical chlorinated organophosphorus flame retardants on Microcystis aeruginosa.

The potential accumulation of chlorinated organophosphorus flame retardants (Cl-OPFRs) in aquatic environments sparked interest in studying the effects of Cl-OPFRs on cyanobacterial blooms. In this work, two common Cl-OPFRs, tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and tris(2-chloroethyl) phosphate (TCEP), induced dose-dependent biphasic effect on bloom-forming M. aeruginosa. The hormetic response to low-dose Cl-OPFRs was associated with the upregulation of the type I NADH dehydrogenase (NDH-1) complex and its mediated cyclic electron transfer (CET) pathway, as reflected by a transient post-illumination increase in chlorophyll fluorescence, the dark reduction of P700+ and the change of NDH-1-related gene expression. The increased CET activity and carotenoid content jointly reduced the intracellular ROS production, facilitating cyanobacterial growth. Conversely, a higher concentration of both Cl-OPFRs induced severe inhibition of growth and photosynthetic oxygen-evolving activity through an imbalance between PSII and PSI. Toxic-dose Cl-OPFRs inhibited state transition and fixed cells into the State I with a higher PSII/PSI ratio, as indicated by chlorophyll fluorescence induction, 77 K fluorescence emission spectra and photosystem stoichiometry. The elevated PSII/PSI ratio created an imbalance between the two photosystems and eventually lead to ROS overproduction, which generate adverse effects on cell growth. This work provides important insights into the hormetic mechanism of Cl-OPFRs on Microcystis aeruginosa and their potential roles in harmful cyanobacteria blooms.

Toxicity of triphenyl phosphate toward the marine rotifer Brachionus plicatilis: Changes in key life-history traits, rotifer-algae population dynamics and the metabolomic response.

Triphenyl phosphate (TPhP) is used as a flame retardant that gradually leaks from products into the marine environment and thus may threaten low-trophic-level marine organisms, such as zooplankton. To assess the effect of TPhP on these taxa, we treated the marine rotifer Brachionus plicatilis as a target and examined the changes in key life history parameters and the metabolome after exposure to TPhP at 0.02, 1 and 5 mg/L. Additionally, the rotifer-Phaeocystis population dynamics (a simulation of the prey-predator relationship) were studied under TPhP stress. Our results showed that TPhP at 1 and 5 mg/L reduced the average lifespan and the total offspring number and prolonged the prereproductive time, suggesting damage to survival and fecundity. In the 0.02 mg/L group, no obvious damage occurred in the overall condition of rotifers, but the volume of parental rotifers after the first brood decreased. This implied that rotifers sacrificed somatic growth to reproduction in the initial period of TPhP exposure at the low concentration. All the tested TPhP concentrations altered the rotifer-Phaeocystis population dynamic changes, especially that 1 mg/L TPhP reduced the ability of rotifers to remove this harmful alga, as evidenced by the decrease in the maximum population density of rotifers and the extended time to P. globosa extinction. At the molecular level, metabolomics identified 84 and 206 differentially expressed metabolites, most of which were enriched in glycerophospholipid metabolism, steroid biosynthesis and sphingolipid metabolism. Nile red staining showed a decrease in neutral lipids in rotifers, further indicating a disorder of lipid metabolism induced by TPhP. Moreover, the balance between ROS production and the defense system was disrupted by TPhP, which contributed to its toxicity. This finding will promote the understanding of the ecological risk and mode of action of TPhP in aquatic environments.

Cyto-Genotoxic and Transcriptomic Alterations in Human Liver Cells by Tris (2-Ethylhexyl) Phosphate (TEHP): A Putative Hepatocarcinogen.

Tris (2-ethylhexyl) phosphate (TEHP) is an organophosphate flame retardant (OPFRs) which is extensively used as a plasticizer and has been detected in human body fluids. Contemporarily, toxicological studies on TEHP in human cells are very limited and there are few studies on its genotoxicity and cell death mechanism in human liver cells (HepG2). Herein, we find that HepG2 cells exposed to TEHP (100, 200, 400 µM) for 72 h reduced cell survival to 19.68%, 49.83%, 58.91% and 29.08%, 47.7% and 57.90%, measured by MTT and NRU assays. TEHP did not induce cytotoxicity at lower concentrations (5, 10, 25, 50 µM) after 24 h and 48 h of exposure. Flow cytometric analysis of TEHP-treated cells elevated intracellular reactive oxygen species (ROS), nitric oxide (NO), Ca++ influx and esterase levels, leading to mitochondrial dysfunction (ΔΨm). DNA damage analysis by comet assay showed 4.67, 9.35, 13.78-fold greater OTM values in TEHP (100, 200, 400 µM)-treated cells. Cell cycle analysis exhibited 23.1%, 29.6%, and 50.8% of cells in SubG1 apoptotic phase after TEHP (100, 200 and 400 µM) treatment. Immunofluorescence data affirmed the activation of P53, caspase 3 and 9 proteins in TEHP-treated cells. In qPCR array of 84 genes, HepG2 cells treated with TEHP (100 µM, 72 h) upregulated 10 genes and downregulated 4 genes belonging to a human cancer pathway. Our novel data categorically indicate that TEHP is an oxidative stressor and carcinogenic entity, which exaggerates mitochondrial functions to induce cyto- and genotoxicity and cell death, implying its hepatotoxic features.

[Analytical method of organophosphorus flame retardants in fish by ultra-high performance liquid chromatography-tandem mass spectrometry based on EMR-Lipid purification].

OBJECTIVE: A method for simultaneous determination of 11 kinds of organophosphorus flame retardants in fish was established by using the EMR-Lipid cleaning agent and ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS). METHODS: The samples were extracted by ultrasonic with 0.5% formic acid acetonitrile solution. The lipid removal product EMR-lipid was used for lipid purification. The co-extracts were further removed by magnesium sulfate, N-propyl ethylene amine(PSA) and graphitized carbon black(GCB) purification agent. The target compounds were separated on an ACQUITY UPLC® BEH C_(18) column(100 mm×2.1 mm, 1.7 µm), detected by electrospray ionization(ESI) and positive ion multiple reaction monitoring mode, the internal standard method and external standard method are quantitatively evaluated, and external standard method was adopted. RESULTS: The 11 kinds of organophosphorus flame retardants had a good linear relationship in the range of 0.5-50 µg/L(tris(2-ethylhexyl) phosphate 0.05-5 µg/L) with r>0.999. The limits of detection were 0.004-1.029 µg/kg and the limits of quantitation were 0.012-3.094 µg/kg. The average recoveries at three spiked levels(low, medium and high) were 80.0%-111.2% with the relative standard deviations all less than 10%(n=6). CONCLUSION: The method could be used for the determination of trace organophosphorus flame retardants in freshwater fish with accurate and reliable result.

Assessing decontamination and laundering processes for the removal of polycyclic aromatic hydrocarbons and flame retardants from firefighting uniforms.

Firefighter uniforms protect firefighters from exposure to potentially harmful chemicals including a range of semi-volatile organic compounds (SVOCs). Contaminated uniforms can become a secondary source of firefighters' exposure to these chemicals. There is inconsistency on the removal efficiency of SVOCs during the cleaning, laundering and field decontamination of firefighting uniforms. Therefore, this study aims to assess how effective decontamination and laundering processes are in reducing firefighter uniforms as a vector for transport and exposure to SVOCs. Firefighters who had attended a controlled house fire and simulated container burns had their uniforms sampled pre- and post-laundering. Clean station wear was laundered with contaminated uniforms and after a load of contaminated uniforms to assess inter and intra load contamination. Surface wipes were collected from uniforms across 12 fire stations, after they had returned from a laundering provider. Concentrations of 13 polycyclic aromatic hydrocarbons (PAHs), six organophosphate flame retardants (OPFRs) and seven polybrominated diphenyl ethers (PBDEs) were measured in the collected samples. The concentrations of ∑13 PAHs in firefighters uniforms ranged between 0.063 and 43 µg g-1, while concentration of ∑6 OPFRs were between 0.061 and 90 µg g-1 with ∑7 PBDEs concentrations being measured between 0.00054 and 0.97 µg g-1.The highest concentrations of ∑13 PAHs were measured on the outer layers of gloves at an average of 19 µg g-1, with the highest ∑6 OPFRs concentrations being measured in the middle layers of gloves at an average of 31 µg g-1. The highest ∑7 PBDEs concentrations were measured on the shell layers of turnout jackets at 0.42 µg g-1. The significant reduction in ∑13 PAHs after laundering or decontamination was only found in 3 of the 16 sampled areas from firefighting uniforms. No significant differences were found in the between pre- and post-laundering concentrations of ∑6 OPFRs or ∑7 PBDEs in firefighting uniforms. The current laundering techniques do not appear to effectively remove PAHs, OPFRs and PBDEs at the measured concentrations from firefighters' uniforms. Further research is required to assess if chemical exposure though firefighting uniforms poses a health risk to firefighters and to develop methods for the removal of SVOCs from firefighting uniforms.

Interlaboratory comparison investigations (ICIs) and external quality assurance schemes (EQUASs) for flame retardant analysis in biological matrices: Results from the HBM4EU project.

The European Human Biomonitoring Initiative (HBM4EU) is coordinating and advancing human biomonitoring (HBM). For this purpose, a network of laboratories delivering reliable analytical data on human exposure is fundamental. The analytical comparability and accuracy of laboratories analysing flame retardants (FRs) in serum and urine were investigated by a quality assurance/quality control (QA/QC) scheme comprising interlaboratory comparison investigations (ICIs) and external quality assurance schemes (EQUASs). This paper presents the evaluation process and discusses the results of four ICI/EQUAS rounds performed from 2018 to 2020 for the determination of ten halogenated flame retardants (HFRs) represented by three congeners of polybrominated diphenyl ethers (BDE-47, BDE-153 and BDE-209), two isomers of hexabromocyclododecane (α-HBCD and γ-HBCD), two dechloranes (anti-DP and syn-DP), tetrabromobisphenol A (TBBPA), decabromodiphenylethane (DBDPE), and 2,4,6-tribromophenol (2,4,6-TBP) in serum, and four metabolites of organophosphorus flame retardants (OPFRs) in urine, at two concentration levels. The number of satisfactory results reported by laboratories increased during the four rounds. In the case of HFRs, the scope of the participating laboratories varied substantially (from two to ten) and in most cases did not cover the entire target spectrum of chemicals. The highest participation rate was reached for BDE-47 and BDE-153. The majority of participants achieved more than 70% satisfactory results for these two compounds over all rounds. For other HFRs, the percentage of successful laboratories varied from 44 to 100%. The evaluation of TBBPA, DBDPE, and 2,4,6-TBP was not possible because the number of participating laboratories was too small. Only seven laboratories participated in the ICI/EQUAS scheme for OPFR metabolites and five of them were successful for at least two biomarkers. Nevertheless, the evaluation of laboratory performance using Z-scores in the first three rounds required an alternative approach compared to HFRs because of the small number of participants and the high variability of experts' results. The obtained results within the ICI/EQUAS programme showed a significant core network of comparable European laboratories for HBM of BDE-47, BDE-153, BDE-209, α-HBCD, γ-HBCD, anti-DP, and syn-DP. On the other hand, the data revealed a critically low analytical capacity in Europe for HBM of TBBPA, DBDPE, and 2,4,6-TBP as well as for the OPFR biomarkers.

Rapid determination of 13 organophosphorus flame retardants in milk by using modified quick, easy, cheap, effective, rugged, and safe technique, solid-phase extraction, and HPLC-MS/MS.

Organophosphorus flame retardants are a class of widely used plasticizers and flame retardants. In this study, an analytical methodology for the simultaneous determination of 13 organophosphorus flame retardants in milk was developed by using high-performance liquid chromatography-tandem mass spectrometry in combination with a modified quick, easy, cheap, effective, rugged, and safe technique and solid-phase extraction. The experimental parameters of the sample purification procedure and high-performance liquid chromatography-tandem mass spectrometry were optimized. The developed method was validated in terms of linearity, limits of detection, recovery, and precision. The method showed a linear response in the 1-100 ng/mL concentration range and the limits of detection ranged from 0.001 to 0.3 ng/mL. The mean recoveries for most organophosphorus flame retardants were in the ranges of 75.0-115.8% (spiked at 2.5 ng/mL) and 76.7-124.8% (spiked at 25 ng/mL), with relative standard deviations of <13.09%. The developed methodology was successfully applied to the analysis of nine human milk samples and nine commercial cow milk samples. Eleven organophosphorus flame retardants were detected in the human milk samples, with median concentrations that ranged from lower than the limit of detection to 1.47 ng/mL, and only nine organophosphorus flame retardants were detected in cow milk samples, with median levels of <0.32 ng/mL.

Bone developmental toxicity of organophosphorus flame retardants TDCIPP and TPhP in marine medaka Oryzias melastigma.

The global phase-out has decreased the use of polybrominated diphenyl ethers (PBDEs), thereby, rapidly increasing the production and use of their important surrogates, organophosphorus flame retardants (OPFRs). Currently, OPFRs are often found at higher levels in the environments compared to PBDEs. Although the two typical OPFRs, tris (1,3-dichloroisopropyl) phosphate (TDCIPP) and triphenyl phosphate (TPhP), have been frequently detected in marine environments with significant concentrations, their toxicity to marine organisms remains unknown. We used Oryzias melastigma to investigate and compare their developmental toxicity in marine organisms through two-generational chronic exposure. The results showed that TDCIPP and TPhP exposure shortened the body length and length of the pectoral fin of O. melastigma. Both TDCIPP and TPhP deformed the pectoral fins in the 1st fry and caused spinal curvature in adult fish. Therefore, these two chemicals may pose potential risks to marine fish and marine ecosystems. Further studies suggested that although these two chemicals caused similar developmental bone toxicity, they had different modes of modulating the expression of bone developmental genes such as, bmp4, bmp2 and runx2.

Occurrence and risk evaluation of organophosphorus flame retardants in two urban rivers in Yangtze River Delta.

The occurrence and profiles of organophosphate flame retardants (OPFRs) were investigated in the Huangpu and Shiwuli Rivers, two urban rivers in the Yangtze River Delta, China. The total concentrations of OPEs were found at part-per-trillion ranges, with average concentrations that ranged from 424 to 1.84 × 103 ng L-1 for Huangpu River and 221 to 1.84 × 103 ng L-1 for Shiwuli River. Three chlorinated OPFRs including tris(chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl) phosphate (TCIPP), and tris(1,3-dichloroisopropyl) phosphate (TDCIPP) were the most abundant compounds among the investigated OPFRs, accounting for 90.6-99.8% of total concentrations. In Huangpu River, the OPFR concentrations were significantly higher in the dry season than in the wet season which indicates obvious seasonal variation. Chlorinated OPFR concentrations differed significantly between upstream and downstream reaches of the Shiwuli River, as the result of geographic features and wastewater discharge. Estimated risk was calculated to compare predicted no-effect concentrations (PNEC) to observed concentrations of OPFRs. The results indicated no significant acute adverse effects of OPFRs in the two urban rivers for fish, daphnia, or algae.