Tributoxyethyl Phosphate Research Articles

Identification of Primary Organophosphate Esters Contributing to Enhanced Risk of Gestational Diabetes Mellitus Based on a Case-Control Study.

Epidemiological studies on associations of organophosphate ester (OPE) exposure and gestational diabetes mellitus (GDM) risk, which remain rare and inconclusive, were carried out with a case-control population comprising 287 GDM and 313 non-GDM pregnant women recruited from Tianjin. The GDM group suffered distinctly higher serum concentrations of tri-n-butyl phosphate (TNBP), tri(2-butoxyethyl) phosphate (TBOEP), triphenyl phosphate (TPHP), tri-iso-propyl phosphate (TIPP), and tri(1-chloro-2-propyl) phosphate (TCIPP) than the healthy control group (p < 0.001). Traditional analysis methods employed for either individual or mixture effects found positive correlations (p < 0.05) between the concentrations of five OPEs (i.e., TNBP, TBOEP, TPHP, TIPP, and TCIPP) and the incidence of GDM, while 2-ethylhexyl diphenyl phosphate, tri(1-chloro-2-propyl) phosphate, and bis(2-ethylhexyl) phosphate exhibited opposite effects. Three machine learning methods considering the concurrence of OPE mixture exposure and population characteristics were applied to clarify their relative importance to GDM risk, among which random forest performed the best. Several OPEs, particularly TNBP and TBOEP ranking at the top, made greater contributions than some demographical characteristics, such as prepregnancy body mass index and family history of diabetes, to the occurrence of GDM. This was further validated by another independent case-control population obtained from Hangzhou.

Distribution, traceability, and risk assessment of organophosphate flame retardants in agricultural soils along the Yangtze River Delta in China.

Severe pollution threatens the ecosystem and human health in the Yangtze River Delta (YRD) in China because of the rapid development of industry in this area. This study examines the types, distribution, concentration, and origin of fourteen typical organophosphate flame retardants (OPFRs) in agricultural soils within the YRD region to offer insights for pollutant control and policy-making. The total concentration of OPFRs (ΣOPFRs) varied between 79.19 and 699.58 μg/kg dry weight (dw), averaging at 209.61 μg/kg dw. Among the OPFRs detected, tributoxyethyl phosphate (TBEP) was identified as the main congener, followed by tri-n-butyl phosphate (TnBP), tris(2-chloroisopropyl) phosphate (TCPP), and trimethyl phosphate (TMP). Source analysis, conducted through correlation coefficients and PCA, indicated that OPFRs in agricultural soils within the YRD region mainly originate from emissions related to plastic products and transportation. The health risk exposure to ΣOPFRs in agricultural soil was considered negligible for farmers, with values below 1.24 × 10-2 and 1.76 × 10-9 for noncarcinogenic and carcinogenic risks, respectively. However, the ecological risk of ΣOPFRs in all the samples ranged from 0.08-1.08, indicating a medium to high risk level. The results offer a comprehensive understanding of OPFR pollution in agricultural soils in the YRD region and can be useful for pollution control that mitigates ecological and health risks in this region.

Occurrence, Fate, and Mass Balance Analysis of Organophosphate Flame Retardants in a Municipal Wastewater Treatment Plant in Hunan Province, China

The occurrence, distribution, removal, and mass loadings of common organophosphate flame retardants (OPFRs) in an advanced municipal wastewater treatment plant (WWTP) were comprehensively investigated. The OPFRs were mainly partitioning in the dissolved phase, and the total concentrations ranged from 1364 to 1701 ng/L in influent, 678~1064 in effluent, and 177~470 ng/g dw in residual sludge. Tributoxyethyl phosphate and tris(2-chloroethyl) phosphate were the abundant compounds in both the dissolved phase and adsorbed phase. The removal frequencies and mechanisms of the OPFRs were highly associated with the properties of compounds. According to the mass balance analysis, 14.9%, 13.0%, and 11.2% of the total OPFR loads were removed in the traditional treatment, tertiary treatment, and to the sludge, respectively. The mass loadings and environmental emissions of the OPFRs were 0.67~291 μg/d/person and 0.57~107 μg/d/person, respectively. The effluent discharged from the WWTP posed ecological risks to the receiving river, which requires being paid more attention.

OPFR removal by white rot fungi: screening of removers and approach to the removal mechanism.

The persistent presence of organophosphate flame retardants (OPFRs) in wastewater (WW) effluents raises significant environmental and health concerns, highlighting the limitations of conventional treatments for their remotion. Fungi, especially white rot fungi (WRF), offer a promising alternative for OPFR removal. This study sought to identify fungal candidates (from a selection of four WRF and two Ascomycota fungi) capable of effectively removing five frequently detected OPFRs in WW: tributyl phosphate (TnBP), tributoxy ethyl phosphate (TBEP), trichloroethyl phosphate (TCEP), trichloro propyl phosphate (TCPP) and triethyl phosphate (TEP). The objective was to develop a co-culture approach for WW treatment, while also addressing the utilization of less assimilable carbon sources present in WW. Research was conducted on carbon source uptake and OPFR removal by all fungal candidates, while the top degraders were analyzed for biomass sorption contribution. Additionally, the enzymatic systems involved in OPFR degradation were identified, along with toxicity of samples after fungal contact. Acetate (1.4 g·L-1), simulating less assimilable organic matter in the carbon source uptake study, was eliminated by all tested fungi in 4 days. However, during the initial screening where the removal of four OPFRs (excluding TCPP) was tested, WRF outperformed Ascomycota fungi. Ganoderma lucidum and Trametes versicolor removed over 90% of TnBP and TBEP within 4 days, with Pleorotus ostreatus and Pycnoporus sanguineus also displaying effective removal. TCEP removal was challenging, with only G. lucidum achieving partial removal (47%). A subsequent screening with selected WRF and the addition of TCPP revealed TCPP's greater susceptibility to degradation compared to TCEP, with T. versicolor exhibiting the highest removal efficiency (77%). This observation, plus the poor degradation of TEP by all fungal candidates suggests that polarity of an OPFR inversely correlates with its susceptibility to fungal degradation. Sorption studies confirmed the ability of top-performing fungi of each selected OPFR to predominantly degrade them. Enzymatic system tests identified the CYP450 intracellular system responsible for OPFR degradation, so reactions of hydroxylation, dealkylation and dehalogenation are possibly involved in the degradation pathway. Finally, toxicity tests revealed transformation products obtained by fungal degradation to be more toxic than the parent compounds, emphasizing the need to identify them and their toxicity contributions. Overall, this study provides valuable insights into OPFR degradation by WRF, with implications for future WW treatment using mixed consortia, emphasizing the importance of reducing generated toxicity.

Occurrence of organophosphorus flame retardants in Xiangjiang River: Spatiotemporal variations, potential affecting factors, and source apportionment

The environmental occurrence of organophosphorus flame retardants (OPFRs) is receiving increasing attention. However, their distribution in the Xiangjiang River, an important tributary in the middle reaches of the Yangtze River, is still uncharacterized, and the potential factors influencing their distribution have not been adequately surveyed. In this study, the occurrence of OPFRs in the Xiangjiang River was comprehensively investigated from upstream to downstream seasonally. Fourteen OPFRs were detected in the sampling area, with a total concentration (∑OPFRs) ranging from 3.16 to 462 ng/L, among which tris(1-chloro-2-propyl) phosphate was identified as the primary pollutant (ND – 379 ng/L). Specifically, ∑OPFRs were significantly lower in the wet season than in the dry season, which may be due to the dilution effect of river flow and enhanced volatilization caused by higher water temperatures. Additionally, Changsha (during the dry season) and Zhuzhou (during the wet season) exhibited higher pollution levels than other cities. According to the Redundancy analysis, water quality parameters accounted for 35.7% of the variation in the occurrence of OPFRs, in which temperature, ammonia nitrogen content, dissolved oxygen, and chemical oxygen demand were identified as the potential influencing factors, accounting for 28.1%, 27.2%, 24.1%, and 11.5% of the total variation, respectively. The results of the Positive Matrix Factorization analysis revealed that transport and industrial emissions were the major sources of OPFRs in Xiangjiang River. In addition, there were no high-ecological risk cases for any individual OPFRs, although tris(2-ethylhexyl) phosphate and tributoxyethyl phosphate presented a low-to-medium risk level. And the results of mixture risk quotients indicated that medium-risk sites were concentrated in the Chang-Zhu-Tan region. This study enriches the global data of OPFRs pollution and contributes to the scientific management and control of pollution.

Degradation of organophosphate flame retardants by a consortium of bacterial strains isolated from the To Lich river, Hanoi

Organophosphate flame retardants (OPFRs) are degraded by a consortium of 10 bacterial strains isolated from the To Lich river, contaminated with OPFRs. The bacterial consortium is cultured in an A-Cl medium supplemented individually with OPFRs (10 mg/l), resulting in optical density at 600 nm ranging from 1 to 1.5. The consortium of 10 bacterial strains exhibits the ability to degrade tris(2-ethylhexyl) phosphate (TEHP) by 98.5 and 100% after two and three days of cultivation, respectively. Triethyl phosphate (TEP) is also degraded by 76.1 and 100% after two and five days of cultivation, respectively. The degradation efficiency of trimethyl phosphate (TMP), tris(2-chloroethyl) phosphate (TCEP), tris(1,3-dichloro-2-propyl) phosphate (TCDPP), and tributoxy ethyl phosphate (TBEP) is also in the range of 97 to 100% after four days of cultivation. In the experiment adding a mixture of 7 substances in OPFRs at a concentration of 10 mg/l for each compound, only TEHP is completely degraded after six days of cultivation. The degradation efficiency of other OPFRs increases from 93.2 to 100% after six days of cultivation. Comparing the degradation rates of OPFRs in both experiments, the results indicate that the cultures supplemented with each compound individually exhibit a faster degradation rate than when a mixture of OPFRs compounds is added.

Metabolic Stability of Eight Airborne OrganoPhosphate Flame Retardants (OPFRs) in Human Liver, Skin Microsomes and Human Hepatocytes

The waste of electrical and electronic equipment (WEEE) is generally considered a secondary raw material for the recovery of valuable components. However, emerging issues regarding the impact of suspended particles arising from WEEE recycling operations are a concern. It was recently demonstrated that samples from three different WEEE plants were rich in organophosphate flame retardants (OPFRs). Since exposure to a xenobiotic can lead to its biotransformation through human metabolism routes, in the present study, the metabolism of eight OPFRs of interest in our sampling campaign (triphenyl phosphate (TPhP), tri-m-tolyl phosphate (TMTP), ethylhexyl diphenyl phosphate (EHDPhP), tributoxyethyl phosphate (TBOEP), diphenyl phosphate (DPhP), trichloroethyl phosphate (TCEP), tris(1,3-dichloropropan-2-yl) phosphate (TDClPP) and bisphenol A bis(diphenyl phosphate) (BDP)) was investigated. Their metabolism was studied at different time points in three matrices: human liver microsomes, human hepatocytes and human skin microsomes. This study, which was run using a common experimental setting, allowed easy comparison of results for each OPFR of interest, and a comparison with other data in the literature was performed. In particular, a number of metabolites not previously described were detected, and for the first time, it was shown that TPhP could be metabolized in human skin microsomes.

Organophosphate Esters Disrupt Steroidogenesis in KGN Human Ovarian Granulosa Cells.

Organophosphate esters (OPEs) are used extensively as flame retardants and plasticizers and are found ubiquitously in the environment and human matrices. Previous studies suggested that exposure to some of these chemicals may disrupt the homeostasis of female sex hormones and have detrimental effects on female fertility. Here, we determined the effects of OPEs on the function of KGN ovarian granulosa cells. We hypothesized that OPEs alter the steroidogenic ability of these cells by dysregulating the expression of transcripts involved in steroid and cholesterol biosynthesis. KGN cells were exposed for 48 hours to 1 of 5 OPEs (1-50μM): triphenyl phosphate (TPHP), tris(methylphenyl) phosphate (TMPP), isopropylated triphenyl phosphate (IPPP), tert-butylphenyl diphenyl phosphate (BPDP), and tributoxyethyl phosphate (TBOEP), or to a polybrominated diphenyl ether flame retardant, 2,2',4,4' tetrabromodiphenyl ether (BDE-47), in the presence or absence of Bu2cAMP. OPEs increased the basal production of progesterone (P4) and 17β-estradiol (E2) and had either no effect or inhibited Bu2cAMP-stimulated P4 and E2 synthesis; exposure to BDE-47 had no effect. Quantitative real-time polymerase chain reaction (qRT-PCR) analyses revealed that OPEs (≥5μM) increased the basal expression of critical genes (STAR, CYP11A1, CYP19A1, HSD3B2, and NR5A1) involved in steroidogenesis; upon stimulation, the expression of all genes tested was downregulated. An overall inhibition in cholesterol biosynthesis was induced by OPEs, characterized by a downregulation in HMGCR and SREBF2 expression. TBOEP consistently showed the least effect. Therefore, OPEs perturbed steroidogenesis in KGN granulosa cells by targeting the expression of steroidogenic enzymes and cholesterol transporters; these effects may have an adverse impact on female reproduction.

Organophosphate esters concentrations in human serum and their associations with Sjögren syndrome

Organophosphate esters (OPEs) are widely used as flame retardants and plasticizers due to their excellent properties. The interference of OPEs on immune function has been proven, but the epidemiological data on OPEs exposure to related immune function diseases, such as sjögren syndrome (SjS), is limited. In cross-sectional study, 283 serum samples were collected from healthy individuals (n = 145) and patients with SjS (n = 138) in Hangzhou, China. Eight OPEs, triethyl phosphate (TEP), tributyl phosphate (TBP), tris (2-chloroethyl) phosphine (TCEP), triphenyl phosphate (TPHP), tri (1-chloro-2-propyl) phosphate (TCIPP), 2-ethylhexyldi-phenyl phosphate (EHDPP), tris (1,3-dichloro-2-propyl) phosphate (TDCIPP), and tri (2-butoxyethyl) phosphate (TBOEP), were frequently measured in serum samples. In addition, we explored the associations between the serum OPEs concentration and the risk of SjS. Results showed that TEP (mean controls 2.17 and cases 3.63 ng/mL) was the most abundant OPEs in the serum samples of the control and case groups, followed by TCIPP (mean controls 0.54 and cases 0.78 ng/mL). Serum TEP, TPHP, and EHDPP concentrations were positively correlated with SjS [odds ratio (OR): 1.97, 1.96, and 2.42, respectively; 95% confidence interval (CI):1.34–2.89, 1.34–2.87, and 1.34–2.87, respectively] in the adjusted model, and a negative correlation of TBP concentrations with SjS in the adjusted model (OR: 0.35, 95% CI: 0.17–0.70) was observed. Compared with the lowest quartile concentrations, the ORs of SjS at the highest quartile concentrations of TEP (OR: 4.93, 95% CI: 2.24–10.82) and TPHP (OR: 4.75, 95% CI:1.89–11.94) were significantly higher. This study suggests that human exposure to OPEs may increase the risk of SjS.

Reproductive toxicity of emerging plasticizers, flame retardants, and bisphenols, using culture of the rat fetal testis†.

The use of bis (2-ethylhexyl) phthalate (DEHP), 2,2'4,4'-tetrabromodiphenyl ether (BDE47), and bisphenol A (BPA), as plasticizers, flame retardants, and epoxy resins, respectively, has been regulated due to their endocrine disrupting activities. Replacements for these chemicals are found in human matrices, yet the endocrine disrupting potential of these emerging contaminants is poorly characterized. We compared the effects of legacy chemicals with those of their replacements using fetal rat testis organ culture. Fetal testes sampled at gestation day 15 were grown ex vivo, and the impact was evaluated after a 3-day exposure to 10 μM of each legacy chemical; two BPA analogs (bisphenol M and bisphenol TMC); three replacements for DEHP/MEHP (2,2,4-trimethyl-1,3-pentanediol diisobutyrate, diisononyl-phthalate, and diisodecyl adipate); or two replacements for BDE47 (tributoxyethyl phosphate and isopropylated triphenyl phosphate). We showed that only BPA and MEHP significantly decrease testosterone secretions after 24 h, while BPM and BPTMC have the opposite effect. Luteinizing hormone-stimulated testosterone was reduced by BPA and MEHP but was increased by BPTMC. After exposure, testes were used for immunofluorescent staining of germ cells, Sertoli cells, and Leydig cells. Interestingly, exposures to BPM or BPTMC induced a significant increase in the Leydig cell density and surface area. A decrease in germ cell density was observed only after treatment with MEHP or BDE47. MEHP also significantly decreased Sertoli cell proliferation. These studies show that some replacement chemicals can affect testicular function, while others appear to show little toxicity in this model. These findings provide essential information regarding the need for their regulation.

Pollution Characteristics of Organophosphate Esters in Frozen Soil on the Eastern Edge of Qinghai-Tibet Plateau

In this study, soil samples were collected from the eastern edge of the Qinghai Tibet Plateau in December 2019. The level and distribution characteristics of organophosphate esters (OPEs) in seasonal frozen soil were analyzed, and their sources were discussed. The results showed that the target analytes including tri-n-butyl phosphate (TnBP), tris(2-ethylhexyl) phosphate (TEHP), tributoxyethyl phosphate (TBEP), triphenyl phosphate (TPhP), tri(2-chloroethyl) phosphate (TCEP), trichloropropyl phosphate (TCPP), and tris-(2,3-dichloropropyl) phosphate (TDCPP) were detected with 100% frequency. Levels of Σ7OPEs in topsoil (0-10 cm) and sub topsoil (10-20 cm) were 146.7-348.7 ng·g-1 (mean:231.1 ng·g-1) and 206.5-333.2 ng·g-1 (mean:260.2 ng·g-1), respectively. The Σ7OPEs content level is comparable to that of urban soil,which is worthy of attention. TBEP and TDCPP were the most abundant compounds in the plateau soil. Point source emissions have significant influence on the spatial distribution of OPEs, and regional deposition of OPEs contributes to all sampling sites. The migration ability of different OPE compounds in soil was different. Stronger migration ability was observed for aromatic OPEs (TPhP) than chlorinated OPEs. Principal component analysis showed that the main sources of OPEs in plateau soil were atmospheric wet and dry deposition, manufactured consumer materials, and the release of OPEs from automobile interior decoration.

Structural Characterization of the Plasticizers' Role in Polymer Inclusion Membranes Used for Indium (III) Transport Containing IONQUEST® 801 as Carrier.

Polymer inclusion membranes containing cellulose triacetate as support, Ionquest® 801 ((2–ethylhexyl acid) -mono (2–ethylhexyl) phosphonic ester) as extractant, and 2NPOE (o–nitrophenyl octyl ether) or TBEP (tri (2–butoxyethyl phosphate)) as plasticizers were characterized using several instrumental techniques (Fourier Transform Infrared Spectroscopy (FT–IR), Reflection Infrared Mapping Microscopy (RIMM), Electrochemical Impedance Spectroscopy (EIS), Differential Scanning Calorimetry (DSC)) with the aim of determining physical and chemical parameters (structure, electric resistance, dielectric constant, thickness, components’ distributions, glass transition temperature, stability) that allow a better comprehension of the role that the plasticizer plays in PIMs designed for In(III) transport. In comparison to TBEP, 2NPOE presents less dispersion and affinity in the PIMs, a plasticizer effect at higher content, higher membrane resistance and less permittivity, and a pronounced drop in the glass transition temperature. However, the increase in permittivity with In (III) sorption is more noticeable and, in general, PIMs with 2NPOE present higher permeability values. These facts indicate that In (III) transport is favored in membranes with chemical environment of high polarity and efficiently plasticized. A drawback is the decrease in stability because of the minor affinity among the components in 2NPOE–PIMs.

Organophosphate esters in water, suspended particulate matter (SPM) and sediments of the Minjiang River, China

As organic pollutants of emerging concern, organophosphate esters (OPEs) have shown toxicity to organisms after entering the water environment. However, research on OPEs in freshwater in Southwest China is very limited. The levels, distribution and partitioning behavior of OPEs in the Minjiang River and their influencing factors is still unknown. In this study, six OPEs, tri-n-butyl phosphate (TnBP), tri(2-chloroethyl)-phosphate (TCEP), trichloropropyl phosphate (TCPP), triphenyl phosphate (TPhP), tributoxyethyl phosphate (TBEP), and tris(2-ethylhexyl)-phosphate (TEHP), were determined in surface water, suspended particle matter (SPM) and sediments of the Minjiang River. The results showed that the average concentrations of Σ6OPEs in surface water, SPM and sediments of the Minjiang River were 199.32 ± 124.95 ng/L, 38463.79 ± 45641.89 ng/g dry weight (dw) and 76.45 ± 28.00 ng/g dw, respectively. High concentrations of OPEs were detected in SPM samples, indicating that more attention should be paid to pollution in SPM. It is worth noting that the variation trend of OPEs in SPM was almost opposite to that in water but basically similar to that in sediment. The proportions of alkyl OPEs in Σ6OPEs increased from surface water to SPM and sediments. Alkyl OPEs were the main pollutants in SPM (10.44%–80.88% of Σ6OPEs, mean of 54.52%) and sediments (59.08%–81.30% of Σ6OPEs, mean of 68.91%), whereas chlorinated OPEs were the most abundant components in surface water (43.16%–75.99% of Σ6OPEs, mean of 55.50%). The water-sediment partition coefficient (logKOC) of OPEs was 4.97–7.58, while the water-SPM partition coefficient was 6.71–10.00. No significant correlations were found between logKOW and logKOC. KOW was not the main factor affecting the distribution of OPEs in the Minjiang River, China.

Distribution, source apportionment and ecological risks of organophosphate esters in surface sediments from the Liao River, Northeast China

A total of 24 surface sediment samples were collected from Liao River, Northeast China. The concentration, spatial distribution, potential source, and ecological risk of 13 organophosphate esters (OPEs) flame retardants and plasticizers were analyzed. The total concentrations of OPEs varied considerably, ranging from 19.7 to 234 ng g−1 dry weight (dw), with the mean concentrations of 64.2 ± 52.2 ng g−1 dw. The OPEs pollution was increasing from upstream to downstream of Liao River. Compared with other sediments of rivers and lakes all over the world, Liao River has been seriously contaminated by OPEs, especially tributyl phosphate (TNBP) and tri-butoxyethyl phosphate (TBOEP). TNBP was the most abundant OPEs, followed by TBOEP and triphenylphosphine oxide. Their mean relative contributions were 26.3%, 12.4% and 11.6%, respectively. Positive matrix factorization indicated that OPEs in sediments from Liao River might be derived from plastic, textile, and polyurethane foam, anti-foam agent, hydraulic fluids, and coatings, indoor release, and chemical process emission. The risk of potential adverse effects of each individually OPEs on aquatic organisms were low (risk quotient less than 0.1). 2-Ethylhexyl diphenyl phosphate was the main substance causing risk.

Distribution and Sources of OPEs in Plants and Snow in Hailuogou

In order to study the effects of atmospheric transport and the wet/dry deposition on the content and distribution of organophosphate esters (OPEs) in remote areas, seven types of OPEs including tri-n-butyl phosphate (TnBP), tri (2-chloroethyl) phosphate (TCEP), trichloropropyl phosphate (TCPP), tridichloropropyl phosphate (TDCPP), triphenyl phosphate (TPhP), tributoxyethyl phosphate (TBEP), and tris (2-ethylhexyl) phosphate (TEHP) were analyzed in plants and snow samples in Hailuogou using gas chromatography-mass spectrometry. The results showed that the pollution levels of the seven OPEs (∑7OPEs) in the plant samples ranged from 43.1 ng·g-1 to 1050.8 ng·g-1. TBEP and TPhP were the main pollutants, accounting for 36%-70% and 24%-80% of the ∑7OPEs, respectively. The main pollutants in the snow in Hailuogou were the same as those in the plants, with TBEP dominating the profile of the ∑7OPEs at 47%, followed by TPhP at 24%. The analysis results of the grid analysis display system (Grads), backward trajectory model, and historical wind data of Hailuogou indicate that the OPEs in this region are affected mainly by atmospheric transmission from Chengdu and the junction of Yunnan Zhaotong and Yibin, Luzhou, and Xichang. The environment of Hailuogou has obviously been disturbed by human activities. It is necessary to conduct thorough investigations of its environmental behavior and to strengthen urban pollution control measures.

Pollution Characteristics of OPEs in the Surface Water and Sediment of the Jinjiang River in Chengdu City

New GC-MS methods were developed for seven typical organophosphate esters (OPEs) including tri-n-butyl phosphate (TnBP), tris (2-ethylhexyl) phosphate (TEHP), tributoxyethyl phosphate (TBEP), triphenyl phosphate (TPhP), tri (2-chloroethyl) phosphate (TCEP), trichloropropyl phosphate (TCPP) and tridichloropropyl phosphate (TDCPP). These methods were used to quantify their concentrations in the surface water and sediment from the Jinjiang River, Chengdu. The recoveries of the target substances were 76%-119% (surface water)and 83%-126% (sediments). Total OPEs (Σ7OPEs) ranged from 689.09 to 10623.94 ng·L-1, with the mean of 3747.58 ng·L-1 in the surface water. The pollution level of each monomer was in the order TBEP > TCEP > TPhP > TEHP > TCPP > TnBP. TBEP was the predominant pollutant, accounting for 36.50%-95.90% of the Σ7OPEs concentrations. The contents (dw) of the Σ7OPEs ranged from 25.52 to 296.00 ng·g-1 in sediments, and TBEP was also the main pollutant in these samples. No significant correlation existed between the concentrations of OPEs in the surface water and sediments. Alkyl OPEs were the main pollutants in the surface water and sediments. The distribution of OPEs was influenced by the source of emissions and environmental attributes. The pairs TCPP and TnBP, TBEP and TEHP, and TCEP and TPhP might have common sources in the surface water.

Threats of organophosphate esters (OPEs) in surface water to ecological system in Haihe River of China based on species sensitivity distribution model and assessment factor model.

Organophosphate esters (OPEs) are a kind of emerging contaminants, but the information about their pollution profile and ecological risk are still scarce in China. In this study, 31 surface water samples of Haihe River (China) were collected in November 2017, and 11 OPEs were measured, and the ecological risk of OPEs was assessed by means of species sensitivity distribution (SSD) method and assessment factor method. Additionally, Pearson correlation analysis and an international comparison with other rivers in the world were conducted. The results showed that total OPEs ranged from 23.98 to 824.72ngL-1, and the mean value was 228.70ngL-1. The concentration of OPEs decreased as follows: Tri(2-chloroisopropyl) phosphate (TCPP) > Tri(2-chloroethyl) phosphate (TCEP) > Triethyl phosphate (TEP) > Tributoxyethyl phosphate (TBEP) > Triphenyl phosphate (TPhP) > Tripropyl phosphate (TPrP) > Tri(2-ethylhexyl) phosphate (TEHP) > 2-ethylhexyl diphenyl phosphate (EHDPP) > Tri(1,3-dichloro-2-propyl)phosphate (TDCPP) > Tri-n-butyl phosphate (TnBP) > Tri-m-cresyl phosphate (TMPP). TCPP (19.54-160.82ngL-1) and TCEP (N.D.-151.99ngL-1) with the mean value of 76.67 and 53.13ngL-1 respectively were identified as the richest OPEs in Haihe River. The concentration of OPEs slowly increased in the upper reaches of Haihe River, and it tended to be stable in the middle reaches of Haihe River and decreased rapidly from the downstream to the outer sea. Significantly positive correlations occurred among three chlorinated alkyl OPEs (TCEP, TCPP, and TDCPP), suggesting that they might come from the same source. Based on the comparison, the pollution condition of OPEs in Haihe River was low, and TCEP was found to be the most abundant OPEs in China but it was not that in Europe. The ecological risk assessment on the basis of assessment factor method suggested that the risk of OPEs in Haihe River for algae, crustacean, and fish was limited. In addition, the results of SSD method suggested that the combined ecological risk of four OPEs in Haihe River was also low. This study provides information about the pollution status of OPEs in the surface water of China to some extents and a project for the risk estimation based on SSD for prior and emerging flame retardants.

Occurrence, Distribution, and Exposure Risk of Organophosphate Esters in Street Dust from Chengdu, China.

Street dust samples were collected from 31 sampling sites in urban area of Chengdu. The distribution characters of OPEs were analyzed in line with functional districts and industrial layout of the city. The results showed that the detection frequency was tris(2-carboxyethyl) phosphine (TCEP), trichloropropyl phosphate (TCPP), triphenyl phosphate (TPhP), and tributoxyethyl phosphate (TBEP) (100%) > tris(2-ethylhexyl) phosphate (TEHP) (93.5%) > tri-n-butyl phosphate (TnBP) (83.9%) > tridichloropropyl phosphate (TDCPP) (74.2%). The ∑7OPEs concentrations ranged from 94.0 to 1484.6ng/g (mean 512.9 ± 417.5ng/g), and TBEP was the predominant pollutant, accounting for 27.9% of the ∑7OPEs. The highest concentrations were observed in the center, west, and northwest sides of the city. Besides, compared with outer area, the higher concentration in the 1st Ring Road reflected that emissions of OPEs might be associated with the population and consumption of commercial products. The correlations between monomers were statistically significant (p < 0.05) for TnBP/TCPP (p = 0.002), TCEP/TCPP (p = 0.026), and TCEP/TPhP (p = 0.033). The exposure level in adults was 0.11ng/(kg bw day), and in children was 0.20ng/(kg bw day) while hand-to-mouth was the primary mode of transmission. The Risk Quotients (RQs) of OPEs were 5.35 × 10-10-1.46 × 10-5 and 4.99 × 10-10-2.82 × 10-5 for adults and children respectively, with no potential risk.

Organophosphate flame retardants in the indoor and outdoor dust and gas-phase of Alexandria, Egypt

Little is known about the presence of organophosphate flame retardants (OPFRs) as a substitute for polybrominated diphenyl ethers in developing countries. This study investigated - for the first time - concentrations, sources and exposure levels of OPFRs in the indoor and outdoor environments of Alexandria, Egypt, in dust and gas-phase samples. Passive samplers were deployed (n = 78) to determine gaseous concentrations, and various dust samples were collected from apartments (n = 25), working places (n = 14), cars (n = 18), and outdoors (OD, n = 30). Indoor concentrations (air: 7.0–64 pg/m3; dust: 150–1850 ng/g) were significantly higher than outdoor (2.0–16 pg/m3 and 83–475 ng/g) concentrations. Tris-1,3-dichloropropyl phosphate (TDCIPP), tris(1-chloro-2-propyl) phosphate (TCIPP), tri (2-butoxyethyl) phosphate (TBOEP) and triphenyl phosphate (TPHP) dominated in all samples with more indoor variabilities. Profiles of OPFRs in OD and floor dust (collected from carpets and floors) were similar but differed from elevated fine dust (collected 1 m above the floor from all available surfaces), possibly due to the influence of carryover of OD by shoes. Despite the high uncertainty in dust – air partitioning coefficients, log transformed values showed significant linear relationships with log octanol – air-partitioning coefficients in all microenvironments, indicating an equilibrium partitioning between dust and vapor. Exposure assessment indicated the importance of the dermal exposure route for adults and ingestion route for children.

Occurrence of organic phosphates in particulate matter of the vehicle exhausts and outdoor environment – A case study

The occurrence and concentrations of a wide range of organic phosphates (OPEs) in vehicle's exhaust (VPM), ambient air particulate matter (APM), and soil of various urban environments were researched. VPM comes from passenger cars, commercial vehicles, marine and bus engines emitted in New European Driving Cycle tests whereas APM was sampled in several sites of the Upper Silesia region (Poland). APM and VPM collected on filters and soil from the same locations as APM sampling sites were extracted with dichloromethane and extracts analyzed by gas chromatography-mass spectrometry. The OPEs found include aryl phosphates such as triphenyl phosphate (TPhP) and tricresyl phosphate (TCP), alkyl phosphates - triethyl phosphate (TEP), tripropyl phosphate (TPP), tributyl phosphate (TBP) and tri(butoxyethyl)phosphate (TBEP), and alkylchlorinated phosphates including tris-(2-chloroisopropyl) phosphate (TCiPP) and tris(2-chloroethyl) phosphate (TCEP). Occurrence and concentrations of these compounds in the PM investigated are highly variable. It was found that total concentrations in APM are directly related to traffic density in particular sites of the urban environment and a style of a vehicle driving. The highest emission of OPEs was found at a crossroad and city center sites where traffic is the densest and vehicles stops and starts are frequent. Village and residential areas were less exposed to OPEs emission. Since OPEs concentrations show exponential correlations to each other also human exposure to these compounds increases exponentially with increasing traffic density. High TEP and TBP level is tentatively proposed as an indicator of emission from petrol-fueled cars. Concentrations of OPEs in some soil are related to their emission to the air and resistance to degradation of a particular compound since only the most resistant TCiPP and TPhP were identified in soil extracts.