Determination of HFRs and OPFRs in PM2.5 by ultrasonic-assisted extraction combined with multi-segment column purification and GC-MS/MS

Triphenyl phosphate induces cardiotoxicity through myocardial fibrosis mediated by apoptosis and mitophagy of cardiomyocyte in mice

Triphenyl phosphate (TPHP) is an organophosphorus flame retardant, but its cardiac toxicity has not been adequately investigated. Therefore, in the current study, the effect of TPHP on the heart and the underlying mechanism involved was evaluated. C57BL/6 J mice were administered TPHP (0, 5, and 50 mg/kg/day) for 30 days. In addition, H9c2 cells were treated with three various concentrations (0, 50, and 150 μM) of TPHP, with and without the reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine or the mitochondrial fusion promoter M1. TPHP caused cardiac fibrosis and increased the levels of CK-MB and LDH in the serum. TPHP increased the levels of ROS, malondialdehyde (MDA), and decreased the level of superoxide dismutase (SOD) and Glutathione peroxidase (GSH-Px). Furthermore, TPHP caused mitochondrial damage, and induced fusion and fission disorders that contributed to mitophagy in both the heart of C57BL/6 J mice and H9c2 cells. Transcriptome analysis showed that TPHP induced up- or down-regulated expression of various genes in myocardial tissue and revealed enriched apoptosis pathways. It was also found that TPHP could remarkably increase the expression levels of Bax, cleaved Caspase-9, cleaved Caspase-3, and decreased Bcl-2, thereby causing apoptosis in H9c2 cells. Taken together, the results suggested that TPHP promoted mitophagy through mitochondria fusion dysfunction resulting from oxidative stress, leading to fibrosis by inducing myocardial apoptosis.

Exposure, bioaccumulation, and risk assessment of organophosphate flame retardants in crayfish in the middle and lower reaches of the Yangtze River

Organophosphate flame retardants (OPFRs), a novel class of persistent pollutants, are widely distributed in the environment, and their potential health risks have garnered significant global attention in recent years. Crayfish is a popular freshwater crustacean product in China primarily sourced from the middle and lower reaches of the Yangtze River. The purpose of this study was to investigate the exposure levels of OPFRs in crayfish, assess the health and safety risks associated with crayfish consumption, and explore the bioaccumulation of OPFRs in environmental water and sediment on crayfish. Ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was employed to analyze 7 common OPFRs in 106 crayfish samples and 76 environmental samples. The results revealed that OPFRs were detected at a high frequency of 100 % in crayfish, with tripropyl phosphate (TPP) being the predominant pollutant found in edible portions while also exhibiting secondary contamination within the crayfish food chain. Monte Carlo modeling combined with @risk risk assessment software demonstrated that TPP present in crayfish muscles had the most substantial impact on health effects, however, overall OPFR exposure did not pose significant risks to human health. Furthermore, analysis of OPFRs bioenrichment ability indicated that crayfish predominantly accumulated these compounds within their edible parts from surrounding environmental water sources, particularly highlighting TPP's potential for bioaccumulation.

An Initial Survey on Occurrence, Fate, and Environmental Risk Assessment of Organophosphate Flame Retardants in Romanian Waterways

Organophosphate ester flame retardants (OPFRs) are ubiquitous organic pollutants in the environment and present an important preoccupation due to their potential toxicity to humans and biota. They can be found in various sources, including consumer products, building materials, transportation industry, electronic devices, textiles and clothing, and recycling and waste management. This paper presents the first survey of its kind in Romania, investigating the composition, distribution, possible sources, and environmental risks of OPFRs in five wastewater treatment plants (WWTPs) and the rivers receiving their effluents. Samples from WWTPs and surface waters were collected and subjected to extraction processes to determine the OPFRs using liquid chromatography with mass spectrometric detection. All the target OPFRs were found in all the matrices, with the average concentrations ranging from 0.6 to 1422 ng/L in wastewater, 0.88 to 1851 ng/g dry weight (d.w.) in sewage sludge, and 0.73 to 1036 ng/L in surface waters. The dominant compound in all the cases was tri(2-chloroisopropyl) phosphate (TCPP). This study observed that the wastewater treatment process was inefficient, with removal efficiencies below 50% for all five WWTPs. The environmental risk assessment indicated that almost all the targeted OPFRs pose a low risk, while TDCPP, TCPP, and TMPP could pose a moderate risk to certain aquatic species. These findings provide valuable information for international pollution research and enable the development of pollution control strategies.

Determination of 25 polybrominated diphenyl ethers in Chinese mitten crab ecosystems by gas chromatography-mass spectrometry

A sensitive and reliable method for determining 25 polybrominated diphenyl ethers (PBDEs) in Chinese mitten crabs and their ecosystems ranging from the growing environment to edible feed by gas chromatography coupled to triple quadrupole mass spectrometry with advanced electron ionization (GC-AEI-MS/MS) was developed and validated. Accelerated solvent extraction (ASE) and liquid-liquid extraction were used to extract solid and water samples, respectively. On the basis of a traditional acid-base silica column, deactivated silica was added and n-hexane elution was used to increase the effect of separation and purification. Two oven temperature programs were applied to achieve good separation of low brominated congeners and increase the sensitivity of high brominated congeners. The method provided good linearity (>0.9996). The recoveries of four matrices were in the range of 82-115% and the method quantification limits (MQLs) in crabs, feed, sediment and water ranged from 0.36-6 pg per g wet weight, 0.69-22.29 pg per g dry weight, 1.02-25.26 pg per g dry weight, and 2.43-40.14 pg L-1, respectively. The proposed method was used for ten samples from two aquatic sites and PBDEs were detected in Chinese mitten crabs, commercial feed and sediment, with the highest in crabs. This analytical technique can be used to monitor the content and the accumulation behavior of PBDEs in Chinese mitten crab ecosystems or other aquaculture systems.

Occurrence of organophosphorus esters in outdoor air fine particulate matter and comprehensive assessment of human exposure: A global systematic review

Organophosphate esters (OPEs) are widely used in various industrial items, including plastics, textiles, construction materials, electronics, and auto parts. Several studies have investigated the concentration of OPE compounds in the air, where different compounds have been measured. This systematic review aims to investigate and summarize the relationship between exposure concentrations of OPEs in outdoor air and health risk for different OPE compounds, and correlations between OPE compounds in emission sources. PubMed, Scopus, Embase, Web of Science, and Google Scholar were searched from January 2000 to September 2021 to identify relevant research. The quality of the studies was assessed using the OHAT risk of bias tool. Spearman's correlation and principal component analysis (PCA) were used to analyze the results and correlation between OPE compounds. A total of 7669 manuscripts were found from the search in 5 databases. Finally, 46 studies were included in the systematic review. According to the median concentrations in the studies that were included, Tris(1-chloro-2-propyl) phosphate (TCIPP) (25%), trimethylphenyl phosphate(TMPP) (19%), Tri-iso-butyl phosphate (TiBP) (12%), Triphenyl phosphate (TPHP) (9%) and Tris(2-chloroethyl) phosphate (TCEP) (8%) had the greatest concentrations of OPEs overall. The cumulative contribution of the two main factors, F1 and F2, from the principal component analysis (PCA) results is 49.81%. The EDI value for the compounds is TCEP > TCIPP > TiBP > TMPP > 2-Ethylhexyl diphenyl phosphate (EHDPP) > TPHP > Tri(2-Ethylhexyl) phosphate (TEHP) > Tri-m-cresyl phosphate (mTCP) > Tris(1, 3-dichloro-isopropyl) phosphate (TDCPP) > Tri-n-butyl phosphate (TnBP). The total amount of non-carcinogenic risk (HQ) was for children > infants > adults. The highest value of HQ was for TCEP, TCIPP, and TMPP, respectively. The highest carcinogenic risk value was for TCEP and TMPP.

Occurrence and removal of organophosphate esters in municipal wastewater treatment plants in Thessaloniki, Greece

An integrate study regarding the occurrence and fate of eleven organophosphate esters (OPEs) was conducted at two wastewater treatment plants (WWTPs) in the area of Thessaloniki, Greece. Both plants employed conventional activated sludge process whereas as last treatment step the first unit use chlorination and the second one ozonation. OPEs were determined in dissolved fraction, total suspended solids and sludge from various treatment stages of WWTPs. Tris (2-butoxyethyl) phosphate (TBOEP), tris (1-chloro-2-propyl) phosphate (TClPP) and triphenylphosphine oxide (TPPO) were the most abundant compounds in influent and treated effluent. Triphenyl phosphate (TPHP) was also abundant in suspended solids and sludge. Total concentrations of ∑₁₁OPEs ranged from 2144 to 9743 ng L^-1 in influents, 1237-2909 ng L^-1 in effluents and 3332-14294 ng g^-1 dw in sludge. Removal rates from 55% to 80% were observed for most OPEs, whereas chlorinated OPEs, especially for tris(2-chloroethyl) phosphate (TCEP) exhibited low removal efficiency. Mass balance analysis showed that biodegradation was the dominant removal mechanism contributing up to 85%. Sorption onto sludge was also relevant removal pathway for most compounds. Emissions of OPEs through effluents and sludge did not pose considerable risk to the aquatic and terrestrial environment.

Ultrasonic Imaging of Cardiovascular Disease Based on Image Processor Analysis of Hard Plaque Characteristics

Cardiovascular disease detection and analysis using ultrasonic imaging expels errors in manual clinical trials with precise outcomes. It requires a combination of smart computing systems and intelligent image processors. The disease characteristics are analyzed based on the configuration and precise tuning of the processing device. In this article, a characteristic extraction technique (CET) using knowledge learning (KL) is introduced to improve the analysis precision. The proposed method requires optimal selection of disease features and trained similar datasets for improving the characteristic extraction. The disease attributes and accuracy are identified using the standard knowledge update. The image and data features are segmented using the variable processor configuration to prevent false rates. The false rates due to unidentifiable plaque characteristics result in weak knowledge updates. Therefore, the segmentation and data extraction are unanimously performed to prevent feature misleads. The knowledge base is updated using the extracted and identified plaque characteristics for consecutive image analysis. The processor configurations are manageable using the updated knowledge and characteristics to improve precision. The proposed method is verified using precision, characteristic update, training rate, extraction ratio, and time factor.

Triphenyl phosphate (TPP) promotes hepatocyte toxicity via induction of endoplasmic reticulum stress and inhibition of autophagy flux

Triphenyl phosphate (TPP), a commonly used organophosphate flame retardant, is frequently found in environmental and biota samples, indicating widespread human exposure. Recent studies have shown that TPP causes hepatotoxicity, but the underlying cellular mechanisms are not fully elucidated. Here, by using normal hepatocyte AML12 cells as a model, we showed that TPP induced apoptotic cell death. RNA sequencing analyses revealed that differentially expressed genes induced by TPP were related to endoplasmic reticulum (ER) stress and autophagy. Immunostaining and western blot results further confirmed that TPP activated ER stress. Interestingly, though TPP increased LC3-II, a canonical marker for autophagy, TPP inhibited autophagy flux rather than induced autophagy. Interestingly, TPP-induced ER stress facilitated autophagy flux inhibition and apoptosis. Furthermore, inhibition of autophagy aggravated, and activation of autophagy attenuated apoptosis induced by TPP. Collectively, these results uncovered that ER stress and autophagy flux inhibition were responsible for TPP-induced apoptosis in mouse hepatocytes. Thus, our foundlings provided novel insight into the potential mechanisms of TPP-induced hepatocyte toxicity.

Spatiotemporal distribution and mass loading of organophosphate flame retardants (OPFRs) in the Yellow River of China (Henan segment)

During three sampling periods in 2014, systematic investigations were conducted into contamination profiles of ten organophosphate flame retardants (OPFRs) in both suspended particulate phase and water phase in the Yellow River (Henan Area). This research shows that OPFRs exist at lower concentrations in the suspended phase than in the water phase. The median concentration of 10 OPFRs (∑₁₀OPFRs) in the suspended particulate phase was 62.5 ng/g (fluctuating from ND to 6.17 × 10³ ng/g, dw), while their median concentration in the water phase was 109 ng/L (fluctuating from 35.6 to 469 ng/L). Among the selected 10 OPFRs, triethylphosphate (TEP), tris(1-chloro-2-propyl) phosphate (TCPP), and tris(2-chloroethyl) phosphate (TCEP) were the predominant compounds in the water phase (occupying 91.6% of the ∑₁₀OPFRs), while TCPP, TCEP, and tri-o-tolyl phosphate (o-TCP) were the most common in the suspended particulate phase, accounting for 90.1% of the ∑₁₀OPFRs. Across the three sampling periods, there was no significant seasonable variation for OPFRs either in the water phase or in the suspended particulate phase, except for TCEP and TCPP in the water phase. Compared with research findings relating to concentrations of OPFRs around China and abroad, the OPFRs of the Yellow River (Henan Area) in the water phase were at a moderate level. Suspended particles (SS) had a very important impact on the transportation of OPFRs in the studied area, with about 83.9% of ∑₁₀OPFRs inflow attributed to SS inflow and about 81.7% of ∑₁₀OPFRs outflow attributed to SS outflow. The total annual inflow and outflow of OPFRs were 7.72 × 10⁴ kg and 6.62 × 10⁴ kg in the studied area, respectively.

Chemical identity and cardiovascular toxicity of hydrophobic organic components in PM2.5

Numerous experimental and epidemiological studies have demonstrated that exposure to PM_2.5 may result in pathogenesis of several major cardiovascular diseases (CVDs), which can be attributed to the combined adverse effects induced by the complicated components of PM_2.5. Organic materials, which are major components of PM_2.5, contain thousands of chemicals, and most of them are environmental hazards. However, the contamination profile and contribution to overall toxicity of PM_2.5-bound organic components (OCs) have not been thoroughly evaluated yet. Herein, we aim to provide an overview of the literature on PM_2.5-bound hydrophobic OCs, with an emphasis on the chemical identity and reported impairments on the cardiovascular system, including the potential exposure routes and mechanisms. We first provide an update on the worldwide mass concentration and composition data of PM_2.5, and then, review the contamination profile of PM_2.5-bound hydrophobic OCs, including constitution, concentration, distribution, formation, source, and identification. In particular, the link between exposure to PM_2.5-bound hydrophobic OCs and CVDs and its possible underlying mechanisms are discussed to evaluate the possible risks of PM_2.5-bound hydrophobic OCs on the cardiovascular system and to provide suggestions for future studies.

Tris(2,4-di-tert-butylphenyl)phosphate: An Unexpected Abundant Toxic Pollutant Found in PM2.5

A novel pollutant, tris(2,4-di-tert-butylphenyl)phosphate (I168O), was identified in urban fine particulate matter (PM_2.5) samples in a nontargeted screening based on mass spectrometry for the first time. I168O was detected in all samples collected from two typical cities far away from each other in China. The concentrations of I168O reached up to 851 (median: 153) ng/m³, indicating that it was a widespread and abundant pollutant in the air. The antioxidant Irgafos 168 [I168, tris(2,4-di-tert-butylphenyl)phosphite] popularly added in plastics was the most suspected source for the detected I168O. Simulation studies indicated that heating, UV radiation, and water contact might significantly (p < 0.05) transform I168 to I168O. In particular, I168O might be magnificently evaporated into the air at high temperatures. The outdoor inhalation exposure of I168O may exert substantial health risks.

Uptake, Accumulation, and Biomarkers of PM2.5-Associated Organophosphate Flame Retardants in C57BL/6 Mice after Chronic Exposure at Real Environmental Concentrations

Although the bioaccumulation of organophosphate flame retardants (OPFRs) in aquatic organisms has been investigated, little information is available about their bioaccumulation in mammals following chronic inhalation exposure. To address this knowledge gap, C57BL/6 mice were exposed to 7 PM_2.5-associated OPFRs via the trachea to study their bioaccumulation, tissue distribution, and urinary metabolites. Low (corresponding to the real PM_2.5 concentrations occurring during winter in Guangzhou), medium, and high dosages were examined. After 72 days' exposure, ∑OPFR concentrations in tissues from mice in the medium dosage group decreased in the order of intestine > heart > stomach > testis > kidney > spleen > brain > liver > lung > muscle. Of the OPFRs detected in all three exposure groups, chlorinated alkyl OPFRs were most heavily accumulated in mice. We found a significant positive correlation between the bioaccumulation ratio and octanol-air partition coefficient (K_OA) in mice tissues for low log K_OW OPFR congeners (log K_OW ≤ 4, p < 0.05). Three urinary metabolites (di-p-cresyl phosphate: DCrP, diphenyl phosphate: DPhP, dibutyl phosphate: DnBP) were detected from the high dosage group. These results provide important insights into the bioaccumulation potential of OPFRs in mammals and emphasize the health risk of chlorinated alkyl OPFRs.

Do pyrene and Kandelia obovata improve removal of BDE-209 in mangrove soils?

Combined pollution caused by polybrominated diphenyl ethers (PBDEs) and polycyclic aromatic hydrocarbons (PAHs) in mangrove wetlands is serious, with their remediation to be been paid more and more attention. However, little is known about the combined impact of PAHs and mangrove species on removal of PBDEs in contaminated soils. In this study, BDE-209 and pyrene were selected and a 9 months experiment was conducted to explore how BDE-209 removal in contaminated soil varied with pyrene addition and Kandelia obovata planting, and to clarify corresponding microbial responses. Results showed that BDE-209 removals in soil induced by pyrene addition or K. obovata planting were significant and stable after 6 months, with the lowest levels of BDE-209 in combined pyrene addition with K. obovata planting. Unexpected, root uptake of BDE-209 in K. obovata was limited for BDE-209 removal in soil, which was verified by lower total amount of BDE-209 bioaccumulated in K. obovata's root. In soil without K. obovata planting, BDE-209 removal caused by pyrene addition coexisted with changed bacterial abundance at phylum Planctomycetes and Chloroflexi, class Planctomycetacia, and genus Blastopirellula. K. obovata-induced removal of BDE-209 in soil may be related to bacterial enrichment in phylum Proteobacteria, class Gammaproteobacteria and genus Ilumatobacter, Gaiella. Thus, in BDE-209 contaminated soil, microbial community responses induced by pyrene addition and K. obovata planting were different at phylum, class and genus levels. This is the first study demonstrating that pyrene addition and K. obovata planting could improve BDE-209 removal, and differently affected the corresponding responses of microbial communities.

Contamination profiles and potential health risks of organophosphate flame retardants in PM2.5 from Guangzhou and Taiyuan, China

Organophosphate flame retardants (OPFRs) are emerging contaminants in recent years. They can be present in the atmospheric fine particle (PM_2.5), leading to potential adverse effects on humans. In this study, the concentrations and in vitro toxicities of OPFRs in PM_2.5 samples were investigated for one year at Guangzhou and Taiyuan in China. Eleven OPFRs, including chloro-, aryl-, and alkyl-substituted OPFRs, were detected at total concentrations ranging from 3.10 to 544 ng m^-3. Chloro-substituted OPFRs were the dominant contaminants. Based on the statistical analysis, the same contamination sources of all OPFRs were found except for tris(butoxyethyl) phosphate (TBOEP) and triethyl phosphate (TEP), which may come from traffic emission. The results of cell viability and dithiothreitol assays indicated that OPFRs and PM_2.5 could induce the death of normal lung epithelial cells and the production of reactive oxygen species (ROS), respectively. According to the redundancy analysis, the distribution of OPFRs was significantly related to the PM_2.5 concentrations and indirectly associated with ROS production induced by PM_2.5 from Taiyuan. Exposure to PM_2.5-bound OPFRs in Guangzhou and Taiyuan only posed minimum health risks to both toddlers and adults. These findings could provide important evidence to better clarify the contamination profiles and human health risks of OPFRs in atmospheric fine particles.

A Review of a Class of Emerging Contaminants: The Classification, Distribution, Intensity of Consumption, Synthesis Routes, Environmental Effects and Expectation of Pollution Abatement to Organophosphate Flame Retardants (OPFRs)

Organophosphate flame retardants (OPFRs) have been detected in various environmental matrices and have been identified as emerging contaminants (EC). Given the adverse influence of OPFRs, many researchers have focused on the absorption, bioaccumulation, metabolism, and internal exposure processes of OPFRs in animals and humans. This paper first reviews the evolution of various types of flame retardants (FRs) and the environmental pollution of OPFRs, the different absorption pathways of OPFRs by animals and humans (such as inhalation, ingestion, skin absorption and absorption), and then summarizes the environmental impacts of OPFRs, including their biological toxicity, bioaccumulation, persistence, migration, endocrine disruption and carcinogenicity. Based on limited available data and results, this study also summarizes the bioaccumulation and biomagnification potential of OPFRs in different types of biological and food nets. In addition, a new governance idea for the replacement of existing OPFRs from the source is proposed, seeking environmentally friendly alternatives to OPFRs in order to provide new ideas and theoretical guidance for the removal of OPFRs.

Acute exposure to triphenyl phosphate inhibits the proliferation and cardiac differentiation of mouse embryonic stem cells and zebrafish embryos

Attention has recently paid to the interaction of triphenyl phosphate (TPHP) and body tissues, particularly within the reproductive and development systems, due to its endocrine-disrupting properties. However, the acute effects of TPHP on early embryonic development remain unclear. Here, we used mouse embryonic stem cells (mESC) and zebrafish embryos to investigate whether TPHP is an embryo toxicant. First, we found that continuous exposure of TPHP decreased the proliferation and increased the apoptotic populations of mESCs in a concentration-dependent manner. Results of mass spectrometry showed that the intracellular concentration of TPHP reached 39.45 ± 7.72 µg/g w/w after 3 hr of acute exposure with TPHP (38.35 μM) but gradually decreased from 3 hr to 48 hr. Additionally, DNA damage was detected in mESCs after a short-term treatment with TPHP, which in turn, activated DNA damage responses, leading to cell cycle arrest by changing the expression levels of p53, proliferating cell nuclear antigen, and Y15-phosphorylated Cdk I. Furthermore, our results revealed that short-term treatment with TPHP disturbed cardiac differentiation by decreasing the expression levels of Oct4, Sox2, and Nanog and transiently reduced the glycolysis capacity in mESCs. In zebrafish embryos, exposure to TPHP resulted in broad, concentration-dependent developmental defects and coupled with heart malformation and reduced heart rate. In conclusion, the two models demonstrate that acute exposure to TPHP affects early embryonic development and disturbs the cardiomyogenic differentiation.