Tris 2-ethylhexyl Phosphate Research Articles

Occurrence of emerging brominated flame retardants and organophosphate esters in marine wildlife from the Norwegian Arctic

To understand the exposure and potential sources of emerging brominated flame retardants (EBFR) and organophosphate esters (OPEs) in marine wildlife from the Norwegian Arctic, we investigated concentrations of EBFRs in 157 tissue samples from nine species of marine vertebrates and OPEs in 34 samples from three whale species. The samples, collected from a wide range of species with contrasting areal use and diets, included blubber of blue whales, fin whales, humpback whales, white whales, killer whales, walruses and ringed seals and adipose tissue and plasma from polar bears, as well as adipose tissue from glaucous gulls. Tris(2-ethylhexyl) phosphate (TEHP) and tris(2-chloroisopropyl) phosphate (TCIPP) ranged from <0.61 to 164 and < 0.8–41 ng/g lipid weight, respectively, in blue whales and fin whales. All other EBRFs and OPEs were below the detection limit or detected only at low concentration. In addition to the baseline information on the occurrence of EBFRs and OPEs in marine wildlife from the Arctic, we provide an in-depth discussion regarding potential sources of the detected compounds. This information is important for future monitoring and management of EBFRs and OPEs.

Occurrence, correlation, and partitioning of organophosphate esters in soil and tree bark from a megacity, Western China.

Concern over the influences of constant addition of emerging anthropogenic chemicals to the environment has become a public issue during the rapid urbanization. Here, we investigated the occurrence of organophosphate esters (OPEs) in soil and corresponding tree bark in a megacity, Western China. Our results showed levels of OPEs in tree bark (1250 ± 573ng/g dry weight (dw)) were 1-2 orders of magnitude higher than those in soil (40.4 ± 30.8ng/g dw). Rooster Mountain is a background mountain area, exhibiting significantly lower concentrations of OPEs in soil and tree bark than those in other sites with relatively high population density. This result highlights the effect of human activities on the distribution of OPEs in environmental matrices. Alkyl-OPEs were predominant compounds in soil, whereas halogenated- (Cl-) OPEs were characterized in tree bark. Furthermore, tris(2-chloroethyl) phosphate (TCEP) positively correlated with tris(2-chloroisopropyl) phosphate (TCIPP) in soil (r2 = 0.43, P < 0.05) while negatively correlated with TCIPP in tree bark (r2 = 0.31, P < 0.05). The ratios of logarithm concentrations of OPEs in tree bark to those in soil correlated well with logKOA values of OPEs from 6 to 10, indicating the equilibrium status was achieved between OPE partitioning in soil and in tree bark. Nevertheless, tris (2-butoxyethyl) phosphate (TBEP) and tris(2-ethylhexyl) phosphate (TEHP) with high values of logKOA deviated from this linear tendency, which was possibly due to the fact that they were subjected to the particle-bound deposition process, leading to partition into the soil.

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.

Organophosphate flame retardants induce oxidative stress and Chop/Caspase 3-related apoptosis via Sod1/p53/Map3k6/Fkbp5 in NCI-1975 cells

Organophosphate flame retardants (OPFRs) have been ubiquitously detected in dust and air which could cause damage to human health through inhalation. Currently the understanding of their adverse effects and potential mechanisms on the lung are still limited. In this study, human non-small cell lung cancer cell line NCI-H1975 was used to investigate the cytotoxicity, oxidative stress, cellular apoptosis of 9 typical OPFRs with concentrations varied from 0 to 200 μM, and their toxic mechanism associated with molecular structure was compared. After 72 h, tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) displayed the highest cytotoxicity, followed by 2-ethylhexyl diphenyl phosphate (EHDPP), tris(2-butoxyethyl) phosphate (TBOEP) and tris(2-chloroisopropyl) phosphate (TCIPP), while tris(2-chloroethyl) phosphate (TCEP) and tris(2-ethylhexyl) phosphate (TEHP) exhibited the least suppression on cell viability. These results indicated that the variation of cytotoxicity on OPFRs could only be partially explained by their ester linkage. Moreover, the overexpression of intracellular reactive oxygen species (ROS), free Ca2+ and cellular apoptosis suggested that exposure to OPFRs can lead to apoptosis related to oxidative stress. Six genes associated with oxidative stress and apoptosis were upregulated dramatically compared with the control, demonstrating OPFRs induced Chop/Caspase 3-related apoptosis by activating Sod1/p53/Map3k6/Fkbp5 expression in NCI-H1975 cells. This is the first study to investigate cytotoxicity and related mechanism on commonly-used OPFRs in NCI-H1975 cells.

Distribution of organophosphate esters influenced by human activities and fluvial-tidal interactions in the Dong Nai River System, Vietnam

Limited information is known about organophosphate esters (OPEs) in sediments of the Dong Nai River System (DNRS) in Vietnam and the influences of complex hydro-sedimentary dynamics on their fate. In this study, 48 surface sediment samples were collected from the Dong Nai-Soai Rap River and its tributary Vam Co River for the determination of 11 target OPEs, together with grain size and total organic carbon (TOC). The total concentrations of OPEs were in the range of 39.4 ng/g dw–373 ng/g dw (mean: 128 ng/g dw), and tris(1-chloro-2-propyl) phosphate (TCPP) was the predominant one with an average contribution of 81%, followed by tri-n-butyl phosphate (TNBP), tris(2-ethylhexyl) phosphate (TEHP). The composition profiles of OPEs at different locations of the DNRS showed no significant differences (p > 0.05). In addition, the distribution of OPEs had been influenced by both human activities and the fluvial-tidal interactions. The highly frequent and various human activities in Ho Chi Minh City (HCMC) leaded to the highest total concentration of OPEs in the midstream site. Based on our dataset, TOC content and grain size of sediments had significant correlation with certain OPEs (p < 0.05), and sediments with higher TOC content and finer grain size in the DNRS were more likely to be deposited in the downstream reach, contributing to the estuary of the DNRS was identified as another hotspot with the second highest concentration of OPEs. Furthermore, the distribution of OPEs in the transects had distinct characteristics, which reflected the joint influence of the human activities and fluvial-tidal interaction as well. However, the mechanism of their influence needed further investigation.

Exposure to organophosphate esters in elderly people: Relationships of OPE body burdens with indoor air and dust concentrations and food consumption.

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

Discovery of contaminants with antagonistic activity against retinoic acid receptor in house dust

Retinoic acid receptors (RARs) control reproduction and development in vertebrates, but little attention has been paid to anthropogenic chemicals exhibiting RAR agoniztic/antagonistic activity. Here we applied a His-RARα pull-down assay combined with high-resolution mass spectrometry to identify chemicals with RARα activity in house dust. After screening, a total of 540 peaks were retained as potential RARα ligands. The mass spectra of 14 chemicals matched with those in the database, of which triphenyl phosphate, galaxolidone, di(2-ethylhexyl) phthalate (DEHP), tris(2-ethylhexyl) phosphate (TEHP), and tris(2-butoxyethyl) phosphate were confirmed by their standards. While one chemical in the sample matched with monophenyl phosphate in the MS/MS database, its retention time was much higher than that of monophenyl phosphate standard, suggesting that it may be an in-source fragment. Its parent ion was finally identified to be m/z 399.2663 using a similarity analysis among chromatographic peaks of hundreds of ions at the same retention time in MS1 spectrum, and bis(2-ethylhexyl) phenyl phosphate (BEHPP) was identified. BEHPP, DEHP, and TEHP were for the first time identified to be RARα antagonists with IC50 values of 6556, 6600, and 2538 nM, respectively. This study improved structural annotation and filled the knowledge gap regarding widespread environmental contaminants with RAR antagonistic activity.

Levels and Distribution of Organophosphate Esters (OPEs) in Typical Megacity Wetland Park Landscape Water Bodies in Southwest China.

Human activities have led to the release of organophosphate esters (OPEs) into the environment. This study aims to investigate the levels and partitioning of OPEs in surface water, suspended particulate matter (SPM) and sediments of landscape waters across eleven parks in the city of Chengdu, a megacity in Southwest China. The average concentration of Σ6OPEs in the SPM samples (median: 2.94 × 103ng/L, 6.88 × 104ng/g dry weight) was 1-3 orders of magnitude higher than that in the surface water (median: 359ng/L) and sediment (median: 82.8ng/g) samples. Tri-n-butyl phosphate (TnBP), tris-(2-chloroethyl)-phosphate (TCEP) and trichloropropyl phosphate (TCIPP) were the primary OPE pollutants in the surface water and SPM samples, while TnBP, tris-(2-butoxyethyl) phosphate (TBEP) and tris-(2-ethylhexyl) phosphate (TEHP) predominated the sediment samples. The higher log Koc values of OPEs in park landscape water bodies estimated in the present study relative to previous studies could be explained by the environmental conditions, such as the sources of the inputs and the hydraulic retention times in these surface waters.

Atmospheric deposition, seasonal variation, and long-range transport of organophosphate esters on Yongxing Island, South China Sea

The South China Sea (SCS), surrounded by developing countries/regions with a huge consumption of flame retardants, is generally contaminated by organophosphate esters (OPEs). However, studies on the occurrence, deposition and long-range atmospheric transport (LRAT) process over the SCS of OPEs compounds are still limited. In this work, 10 OPEs were measured in 100 atmospheric samples collected from Yongxing Island (YXI) in the SCS. The total OPEs concentrations ranged from 1508 to 1968 pg/m3 with 28.6–1416.9 pg/m3 in gas and 95.2–1066.2 pg/m3 in particle partition. The three chlorinated OPEs are present at higher concentrations than the other seven non-chlorinated OPEs. Most OPEs had clear seasonal variations that followed the order: spring>summer≈winter>autumn except for tri-isobutyl phosphate (TIBP) and tris-(2-ethylhexyl) phosphate (TEHP). The particle-bound fraction of the total OPEs had little seasonal variations with a mean value of 0.35. Comparing J-P model and Koa model, it was found that the gas/particle partition in the study area was in non-equilibrium condition. LRAT, controlled by seasonal wind direction, was the predominated factor that led to the seasonal variations of OPEs on YXI. The average daily deposition flux of total OPEs was 13.0 ng/m2 with an annual total deposition of 15.06 g.

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.

Estimation of Trimethoprim by using a New Selective Electrodes dependent on Molecularly Imprinted Polymers

Trimethoprim-MIPs were prepared by using (TMP) as the template as well as allylchloride (AYC) or allylbromide (AYB) as monomer, used (TMPTA) tri methylol propane tri acrylate or ethylene glycol di methyl acrylate (EGDMA) as cross-linker and initiator used (BP) benzyl peroxide. By using different plasticizers (di butyl Phthalate (DBPH), Nitrobenzene (NB), oleic acid (OA) and paraffin) for TMP-MIP1 and (Di butyl sebecate (DBS), Di methyl acrylate (DMA), Tributylphosphate(TBP) and Tris(ethylhexyl phosphate (TEHP) ) for TMP-MIP2. Membranes of MIPs were prepared in PVC matrix. The characterizations of each electrode were determined The Slope range from (55.591 - 40.509) mV/decade, Limit of Detection (1 X 10 -5 - 5 X 10 -6) and Linearity range of electrodes MIPs from (1 X 10 -5 - 1 X 10 -1). Stable Signe of electrode pH from (3-9) and study the selectivity with additives of drugs synthesis (Glucose, Calcium stearate, sodium benzoate and benzoic acid) demonstrate strong selectivity.

Organophosphate Flame Retardants in Car Dust from Thailand and Implications for Human Exposure

Organophosphorus flame retardants (PFRs) are a group of compounds frequently detected in indoor dust that pose high health risks to exposure subjects. The present study reports on the investigation of the levels and profiles of seven target PFRs in car dust samples from Thailand. The samples were collected from the discarded air conditioning (AC) filter of 14 private cars (called AC dust samples) and from the bag filter installed in vacuum cleaners of 10 car washing services (called settled dust samples) in 2019. The concentrations of 7PFRs in AC dust samples were approximately 3,800-91,000 ng/g, whereas those from settled dust samples were about 11,000 to 15,000 ng/g. Tris (2-butoxyethyl) phosphate (TBEP) was found to be the most prominent of PFRs detected in both types of car dust with the highest concentration of 39,000 ng/g for AC filter dust and 10,000 ng/g for settled dust. The main PFR contributors in both dust types were TBEP (80%, 75%), followed by Tris (2-ethylhexyl) phosphate (TEHP) (9%, 5%) and tris(1-chloro-2-propyl)phosphate (TCPP) (7%, 4%), respectively. Tris(2-chloroethyl)phosphate (TCEP) and tri cresyl phosphate (TCP) were not detected in both types of car dust and tris(1,3-dichloro-2-propyl) phosphate (TDCPP) was found only in settled dust samples. According to the results of exposure assessment to PFRs in car dust, the human exposures via ingestion for adults and toddlers ranged from 1.69×10-2 to 2.67 and 10.6 to 2,360 ng/kg/day. The human exposures via inhalation for adults and toddlers ranged from 3.27×10-4 to 5.17x10-2 and 2.58×10-1 to 40.9 ng/kg/day. The highest exposure among PFRs corresponded to TBEP for both adults and toddlers and the risk through ingestion was higher than inhalation intake. Toddlers were more exposed to PFR contaminants in comparison to adults. When comparing the estimated average daily intake (ADI) values with the reference doses (RfDs) for PFRs, it was found that exposure to PFRs in car cabins via inhalation and dust ingestion is unlikely to have adverse human health effects.

Selective Palladium(II) Recovery Using a Polymer Inclusion Membrane with Tris(2-ethylhexyl) Phosphate (TEHP). Experimental and Theoretical Study

Extraction and recovery of palladium continues to be a technologically and economically challenging task, particularly in the recycling process of palladium from scrap automotive catalytic converte...

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.

A reconnaissance study of pharmaceuticals, pesticides, perfluoroalkyl substances and organophosphorus flame retardants in the aquatic environment, wild plants and vegetables of two Saudi Arabia urban areas: Environmental and human health risk assessment

In this study, the occurrence of 12 organophosphorus flame retardants (OPFRs), 64 pesticides, 21 perfluoroalkyl substances (PFASs) and 34 pharmaceuticals and personal care products (PPCPs) in surface water, sediments and vegetation collected from seven locations along the South Riyadh and six locations along the Al-Jubail industrial city (Saudi Arabia) were reported. The median of the concentrations of ƩOPFRs, ƩPesticides, ƩPFASs and ƩPPCPs in water was 297, 231, 29.7 and 3794 ng L−1, respectively, in sediments 56.2, 40.4, 5.66 and 419 ng g−1 d.w., in crops for human consumption of 45.6, 42.0, 0.46 and 42.0 ng g−1, in farm crops of 13.4, 57.5, 3.2 and 637 ng g−1, and in natural vegetation of 51.7, 10.3, 1.88 and 1580 ng g−1. Predominant compounds in all matrices were tris-(1,3-dichloro-2-propyl)phosphate (TClPP), acetamiprid, imidacloprid, caffeine, bisphenol A (BPA), diclofenac and ibuprofen. Tris(2-butoxyethyl) phosphate (TBEP), tris-(2-ethylhexyl)phosphate (TPhP), perfluoroctanoic acid (PFOA), perfluoroalkyl sulfonate (PFOS) and paracetamol were also in many samples but at low concentrations. The contaminants' levels showed similar values in both cities. However, pesticide levels were significantly higher in surface water (p < 0.05) and lower in natural vegetation (p < 0.05) of Riyadh than those of Al-Jubail. The risk assessment for the aquatic biota showed that abamectin, diazinon (pesticides), bisphenol A and caffeine (PPCPs) had the highest risk levels. The cumulative risk assessment showed that the contaminant mixture in all water samples is of concern. As far as the risk to human health is concerned, individual contaminants did not show a significant hazard for the population. However, OPFRs and pesticide requires a closed monitoring since % of admissible daily intakes (ADIs) or reference doses (RfD) are high. This is one of the most comprehensive study covering environmental and human risk assessment of emerging contaminants carried out in Saudi Arabia.

Spatial occurrence and composition profile of organophosphate esters (OPEs) in farmland soils from different regions of China: Implications for human exposure.

The environmental load of organophosphate ester (OPE) flame retardants has caused a series of problems due to their extensive use. The soil matrix, as an ultimate sink for organic pollution, plays a vital part in the fate of OPEs in the environment. In this study, the spatial occurrence, composition profile and health risk of 13 OPE species in farmland soils from four provinces of China were characterized. Excluding tris(2,3-dibromopropyl) phosphate (TDBPP) and ethylhexyl diphenyl phosphate (EHDPP), the remaining eleven OPEs had a high detection frequency (DF) ranging from 60% to 100%. The range of total OPE (ΣOPE) concentrations were 62.3-394ng/g dry weight (dw), with a median of 228ng/g dw. Among these OPEs, tris(2-ethylhexyl) phosphate (TEHP) with a median of 143ng/g dw) was the predominant species, followed by tricresyl phosphate (TCP; median of 20.1ng/g dw) and tris(2-chloroethyl) phosphate (TCEP; median of 17.9ng/g dw). In terms of geographical distribution, significantly lower OPEs levels were found in samples from Heilongjiang (159±47.0ng/g dw) than in those of Guangxi (264±66.0ng/g dw), Henan (252±74.5ng/g dw) and Hubei (242±52.8ng/g dw) provinces. Principal component analysis and Spearman's correlations were used to reveal potential sources of OPEs in the different provincial regions. Health risk exposure to OPEs in farmland soils was at an acceptable level (<1.20×10-5 for non-carcinogenic risk to children as the most sensitive age group; and <6.47×10-10 for carcinogenic risk to adults as the most sensitive age group) at the present detected concentrations. However, TCEP and TEHP, the predominant risk contributors, should be paid more attention.

Optimization of Ni (II) Facilitated Transport from Aqueous Solutions Using a Polymer Inclusion Membrane.

Efficient Ni (II) transport through a polymer inclusion membrane (PIM) was achieved. A central composite design (DCC) coupled to a Derringer’s desirability function (DF) was used to optimize membrane composition using Kelex 100 (HQ) as carrier, cellulose triacetate (CTA) as polymer support, and tris(2-ethylhexyl) phosphate (TEHP) as plasticizer. The effect of components’ contents in the membrane and the interactions among them on Ni (II) migration was evaluated using two normalized function as response variables (GFeed, GStrip). Using the optimal membrane composition, (96 ± 1.5) % of Ni (II) was detected in the strip solution after 48 h of pertraction. The efficiency factors of the system were determined, i.e., permeability (optimization pH of the aqueous samples and initial metal concentration), selectivity (among Zn (II), Pb (II), Cu (II), Ca (II) and Mg (II)), and stability (reuse capability). Ni (II) transport mechanism was proposed and analyzed as well.

Organophosphorus flame retardants in breast milk from Beijing, China: Occurrence, nursing infant's exposure and risk assessment

Organophosphorus flame retardants (OPFRs) are widely used chemicals, whereas data on OPFRs in human being is limited. In this study, thirteen OPFRs were measured in 105 breast milk samples collected from Beijing mothers in 2018. The ∑13OPFRs ranged from <LOD to 106 ng mL−1 (<LOD-6700 ng g−1 lipid weight (lw)), with a median value 10.6 ng mL−1 (157 ng g−1 lw). The most abundant compound was tris(2-ethylhexyl) phosphate (TEHP), followed by triphenyl phosphate (TPhP) and 2-ethylhexyl diphenyl phosphate (EHDPP). The detecting frequencies and contamination levels of OPFRs in our study were higher than those reported in other studies, which indicated that China is one of the most affected regions by OPFRs. In addition, OPFR levels in our study were found to be higher than levels of brominated flame retardants (BFRs) in human milk from China. Based on regression analyses, mothers' personal characters, including age, pregnancy, residing/working location, and educational level were found to be impact factors of some OPFRs in breast milk. Estimated daily intakes (EDI) of the OPFRs for nursing infants via human milk ingest were calculated, and the mean EDIs of the 13 OPFRs ranged from 2.62 to 1640 ng kg−1 bw d−1. Since the mean and max EDIs of most OPFRs were lower than corresponding reference doses (RfDs), the daily OPFR intake for most nursing infants would not cause significant health concerns. However, the max EDIs of two OPFRs, TPhP and EHDPP, with values of 1.09 × 104 and 2190 ng kg−1 bw d−1, respectively, were higher than their corresponding RfDs. To our knowledge, this is the first report on the occurrence of OPFRs in human milk from China.

Newly discovered bis-(2-ethylhexyl)-phenyl phosphate (BEHPP) was a ubiquitous contaminant in surface soils from a typical region, South China

The organophosphate ester (OPE), bis-(2-ethylhexyl)-phenyl phosphate (BEHPP), was recently identified as an abundant contaminant in indoor dust samples; however, its pollution status in other matrices remains unknown. Here, n = 95 surface soil samples were collected from a prefecture-level city (hereafter referred to as D city) in South China during 2019, and further analyzed to accurately determine the concentrations of BEHPP and eight other OPEs, including tris(2-chloroethyl) phosphate (TCEP), tris(1,3-dichloro-isopropyl) phosphate (TDCIPP), triphenyl phosphate (TPHP), tris(2-butoxyethyl) phosphatetris (TBOEP), 2-ethylhexyl diphenyl phosphate (EHDPP), tris(2-ethylhexyl) phosphate (TEHP), 4-biphenylol diphenyl phosphate (BPDPP), and tris(2-biphenyl) phosphate (TBPHP). BEHPP was detected in all six functional areas (agricultural, scenic, commercial, industrial, and residential areas) of this region, and exhibited a high detection frequency of 67.4%, with a median concentration of 0.455 ng/g dry weight (DW range: nd-7.05 ng/g dw), regardless of the functional area. Samples from commercial, industrial, and residential areas contained significantly greater BEHPP concentrations than those from agricultural and scenic areas. Furthermore, strong and statistically significant correlations were observed between BEHPP and other OPE congeners, particularly for TEHP (r = 0.764, p < 0.001), TBOEP (r = 0.687, p < 0.001), and TPHP (r = 0.709, p < 0.001), indicating that BEHPP may have similar commercial applications and sources to these compounds in surface soil. Collectively, this study provides the first evidence of the presence of BEHPP in soil samples, and indicates that this emerging contaminant is widely distributed across all five functional areas of a typical region (South China).

Occurrence and human exposure assessment of organophosphate esters in atmospheric PM2.5 in the Beijing-Tianjin-Hebei region, China

Organophosphate esters (OPEs) in atmospheric fine particles (PM2.5) were comprehensively investigated in the Beijing-Tianjin-Hebei (BTH) region from April 2016 to March 2017. The concentrations of Σ8OPEs in all the five sampling sites ranged from 90 to 8291 pg/m3 (mean 1148 ± 1239 pg/m3; median 756 pg/m3). The highest level (median 1067 pg/m3) was found at one of the urban sites in Beijing, followed by Tianjin (746 pg/m3) and Shijiazhuang (724 pg/m3). Tris(2-chloroethyl) phosphate (TCEP) and tri[(2R)-1-chloro-2-propyl] phosphate (TCPP) were the dominant compounds across the five sampling locations. Generally, the concentrations of chlorinated OPEs were relatively higher in summer than in winter (p < 0.05), but no significant seasonal difference was discovered for non-chlorinated individual OPEs. The concentrations of tri-n-butyl phosphate (TBP), TCEP, TCPP and triphenyl phosphate (TPP) were positively correlated with the meteorological parameters (i.e. temperature and relative humidity) (p < 0.05), indicating an evident influence of meteorological condition on OPE distribution. We observed a negative correlation (p < 0.05) between octanol-air partition coefficients (logKoa) and the ratio of PM2.5-bound OPE concentrations to total suspended particulates-bound OPE concentrations, suggesting that physicochemical properties affect the particle-size distribution of OPEs. Furthermore, the median value of cancer hazard quotients (HQs) of TCEP was higher than TBP and tris(2-ethylhexyl) phosphate (TEHP). The health risk assessment showed that HQ values for children were ~1.6 times higher than those for adults. Relatively higher health risk induced by PM2.5-bound OPEs via inhalation was found during severe hazy days than in clear days.