Sources Of Organophosphate Esters Research Articles

Nationwide Profiling and Source Identification of Organophosphate Esters in Korean Surface Waters Using Target, Suspect, and Non-Target HRMS Analysis

Organophosphate esters (OPEs) are emerging contaminants that serve as alternatives to regulated substances in aquatic environments. A nationwide large-scale assessment for OPEs, including point sources, remains insufficient. To address this issue, we aimed to investigate OPEs occurrence and novel OPEs via comprehensive target, suspect and non-target analysis. Among the 11 target OPEs, 10 were detected at sampling sites distributed evenly nationwide. The highest mean concentrations were measured for tris-(2-butoxyethyl) phosphate (TBOEP) and tris(2-chloroisopropyl) phosphate (TCIPP). The multivariate statistical analysis revealed that TBOEP and TCIPP are essential components for assessing total OPEs pollution. The systematic risk assessment results evaluated the overall risk contribution of TBOEP and the significant risk impact of 2-ethylhexyl diphenyl phosphate. Promising suspect and non-target analysis enabled frequent detection and identification of 6 antioxidant transformation products (TPs), as well as the tentative identification of 14 OPEs and TPs, including 3 di-OPEs. Based on sampling site classification, we confirmed that major OPEs are significantly discharged near point sources. We believe that this is the first attempt to assess the nationwide risk and potential sources of OPEs in Korean surface waters, providing insights that could support further prioritization and regulation efforts.

Characterizing organophosphate esters and chlorinated paraffins in surface soils affected by diverse e-waste disassembling process in South China: Occurrence, distinct emission, and risk assessment

E-waste recycling activities are a crucial emission source of organic pollutants, posing potential risks to the surrounding environment and human health. To understand the potential impact related to diverse e-waste dismantling activities, we investigated two categories of popular flame retardants (i.e., organophosphate esters (OPEs) and chlorinated paraffins (CPs) and their resultant possible ecological risk in 53 surface soil samples from Qingyuan, a well-known e-waste recycling region in South China. Varied concentrations of ΣOPEs (20.5–8720 ng/g) and ΣCPs (920–16800 ng/g) were observed at diverse dismantling sites, while relatively low levels of ΣOPEs (6.13–1240 ng/g) and ΣCPs (14.8–2870 ng/g) were found in surrounding soils. These results indicated that primitive e-waste dismantling processes were the primary emission source of OPEs and CPs in the studied area, with e-waste dumping and manual dismantling being the most important emission sources for OPEs and CPs. More importantly, CPs could be degraded/transformed into more toxic intermediates via dechlorination and decarbonization during the burning of e-waste. Furthermore, our results indicated the potential ecological risks posed by OPEs and CPs related to e-waste recycling.

Unveiling the occurrence and ecological risks of organophosphate esters in seawater of the northern South China Sea

As a class of emerging contaminants in marine environments, organophosphate esters (OPEs) have attracted increasing attention of environmental scientists and policymakers due to their ubiquity and ecotoxicity. However, little is known about the environmental geochemical behaviors of OPEs in seawater of the South China Sea (SCS). In this study, the concentration, composition, pollution source, and ecological risk of twelve typical OPEs were analyzed in the surface seawater of the northern SCS between August and September 2021. The results showed that five out of twelve OPEs were detectable with the total concentration of five OPEs (Σ5OPEs) ranging from 7.17 to 67.6 ng/L in seawater. Chlorinated OPEs (Cl-OPEs) were the predominant OPEs, with a mean concentration of 18.4 ng/L, accounting for more than 69.8 % of Σ5OPEs. Among the detected congeners, tris(2-chloroethyl) phosphate (TCEP) was the most abundant OPE (mean: 14.8 ng/L, 56.2 %), followed by triethyl phosphate (TEP) (mean: 7.75 ng/L, 29.5 %) and tris(1-chloro-2-propyl) phosphate (TCIPP) (mean: 2.07 ng/L, 7.87 %). Principal component analysis and Spearman correlation analysis indicated that terrestrial inputs, atmospheric deposition, and shipping activities were the potential sources of OPEs in the northern SCS. The ecological risk assessment revealed that TCEP posed low threats to algae and low ecological risks were predominantly observed from the mixture of OPEs. This work provides a basis for further investigation into the environmental behavior, toxicity, and risk of OPEs in the SCS and facilitates a better implementation of effective management actions.

Spatiotemporal distribution and transport flux of organophosphate esters in the sediment of the Yangtze River

The Yangtze River Basin is an important area for organophosphate esters (OPEs) consumption and emission. Studies proved high OPE detection in Yangtze River water, but there is limited information about the spatiotemporal distribution and transport flux of OPEs in sediment. The present study investigated 16 OPEs in sediment from upstream to mid-downstream of the Yangtze River. The mean concentration of OPEs was 84.30 ng/g, and alkyl-OPEs was the primary component. Great specific surface area and high content of organic carbon significantly increased OPE concentration in Three Gorges Reservoir (TGR) by physical adsorption and chemical bonds (p < 0.05), making TGR the most contaminated area in mainstream. No significant differences in OPE constituents were found in seasonal distribution. Four potential sources of OPEs were identified by principal component analysis and self-organizing maps, and traffic emissions were the dominant source for OPEs. The hazard quotient model results indicated that aryl-OPEs showed moderate risks in the mainstream of Yangtze River, alkyl-OPEs and Cl-OPEs showed low risks. TGR was a significant sink of OPEs in Yangtze River and buried 7.41 tons of OPEs in 2020, a total of 14.87 tons of OPE were transported into the sea by sediment.

Organophosphate esters (OPEs) pollution characteristics, bioaccumulation and human consumption implication in wild marine organisms from the Yellow River Estuary, China

As the substitutes of polybrominated diphenyl ethers, organophosphate esters (OPEs) with high concentrations have accumulated in the estuaries, bays, and harbors. However, limited information is available about the OPEs in the estuary organism categories, especially under the multiple industrial pressure. This study investigated the occurrence, bioaccumulation and human consumption implication in wild marine organisms from the Yellow River Estuary, where located many petroleum and chemical manufacturing industries. This study found that concentrations of Σ13OPEs ranged from 547 ng/L to 1164 ng/L in seawater (median: 802 ng/L), from 384 to 1366 ng/g dw in the sediment (median: 601 ng/g dw), and from 419 to 959 ng/g dw (median: 560 ng/g dw) in the marine organisms. The congener compositions in the organisms were dominated by alkyl-OPEs (80.7 %), followed by halogenated-OPEs (18.8 %) and aryl-OPEs (0.5 %). Based on the principal component analysis, petrochemical pollution, and industrial wastewater discharge were distinguished as the main plausible sources of OPEs to the YRE ecosystem. Most OPEs had potential or strong bioaccumulation capacity on the organisms, with a positive correlation between log BAF (Bioaccumulation Factor) and log Kow of OPEs. The highest estimated daily intake value of OPEs was tri-n-propyl phosphate, exceeding 300 ng/kg·bw/day via consuming fish. The highest hazard quotients from OPEs ranged from 0.001 to 0.1, indicating a low risk to human health by consuming marine organisms in the YRE. As the consumption of OPEs increases year by year, the risks of OPEs still cannot be ignored.

Seasonal variations of organophosphate esters (OPEs) in atmospheric deposition, and their contribution to soil loading

Organophosphate esters (OPEs) are ubiquitous in surface soil, and atmospheric deposition is considered to be the major pollution source. However, the research on the environmental transport behaviors of OPEs between atmospheric deposition and soil is very limited. In this study, we investigated the contamination levels and seasonal variations of OPEs in atmospheric deposition samples (n = 33) collected from an area of South China every month between February 2021 and January 2022, and evaluated the contribution of OPEs in atmospheric deposition to soil. The concentrations of ∑21target-OPEs ranged from 3670 to 18,600 ng/g dry weight (dw), with a mean of 8200 ng/g dw (median: 7600 ng/g dw). ∑21target-OPEs concentrations in all atmospheric deposition samples exhibited significant seasonal differences (p < 0.05) with higher concentrations observed in winter and lower concentrations in summer. Tris(2,4-di-tert-butylphenyl) phosphate (TDTBPP) was the most dominant target OPE in atmospheric deposition (4870 ng/g dw), and its seasonal variation trend was consistent with ∑21OPEs (p < 0.05). Simultaneously, in order to further explore the effect of atmospheric deposition on the levels of OPEs in soil of the study region, input fluxes and accumulation increments were estimated. Ten OPEs (including seven target OPEs and three suspect OPEs) exhibited high input flux means and accumulation increments, indicating that these compounds are prone to accumulate in soil via atmospheric deposition. It is noteworthy that the non-target phosphonate analyte bis(2,4-di-tert-butylphenyl) dibutyl ethane-1,2-diylbis(phosphonate) (BDTBPDEDBP) was detected at highest median concentration (8960 ng/g dw) in atmospheric deposition. Correspondingly, the average input flux and accumulation increment of BDTBPDEDBP were higher than those of all target and suspect OPEs. Collectively, this study quantifies the environmental transport behavior of OPEs between atmospheric deposition and soil, and provides new evidences for the fact that atmospheric deposition is the important pollution source of OPEs in soil.

Pollution characteristics and risk assessment of organophosphate esters (OPEs) in typical industrial parks in Southwest China.

As alternative substances of PBDEs, organophosphate esters (OPEs), an emerging organic pollutant, were increasingly produced and used in many kinds of industries and consumer products. However, OPEs also have various adverse toxic effects. Information on the pollution levels and exposure to OPEs in related industries is still limited. This study presented data on OPE contamination in the soil, leaf, and river water samples from seven typical industrial parks in Southwest China. Total concentration of seven OPEs (Σ7OPE) including tri-n-butyl phosphate (TnBP), tris-(2-ethylhexyl) phosphate (TEHP), tris-(2-butoxyethyl) phosphate (TBEP), tris-(2-carboxyethyl) phosphine (TCEP), triphenyl phosphate (TPhP), tris-(1,3-dichloro-2-propyl) ester (TDCPP), and tris-(chlorisopropyl) phosphate (TCPP) in the soil samples (36.2 ~ 219.7 ng/g) and the surrounding river water samples (118.9 ~ 287.7 ng/L) were mostly lower than those in other studies, while the Σ7OPE level in the leaves (2053.3 ~ 8152.7 ng/g) was relatively high. There were significant differences in the concentration and distribution of OPEs in the surrounding environment of different industrial parks. TDCPP, TnBP, and TCPP could be used as the characteristic compound in soil samples from auto industrial park, river samples from shoe making industrial park, and leaf samples from logistics park, respectively. The parameter m (the content ratio of chlorinated OPEs to alkyl OPEs) was suggested to distinguish the types of industrial park preliminary. When m ≥ 1, it mainly refers to heavy industries sources such as automobiles, electronics, and machinery, etc. When m<1, it mainly for the light industrial sources such as textile industry, transportation services, and resources processing, etc. For logistics park, furniture park and Wuhou comprehensive industrial park, the volatilization of materials was the main sources of OPEs in the surrounding environment, while more effort was required to strengthen the pollution control and management of the waste water and soil in the pharmacy industrial park, shoe making industrial park and auto industrial park. Risk assessment showed that there was a negligible non-cancer and carcinogenic risk in the soil, while high attention should be paid to the non-cancer risk for children.

Occurrence, distribution, and sources of organophosphate esters (OPEs) in the air of the Indo-China Peninsula Based on a Passive Air Monitoring Network

Organophosphate esters (OPEs) are a class of emerging and ubiquitous contaminants that are attracting increasing attention, and their large-scale use as flame retardants and plasticizers has led to their pervasive presence in the environment, although their broader impacts remain unknown. In this study, 11 OPEs were measured in the atmosphere of Southeast Asia and Southwest China during 2016. The ∑11OPEs were higher in this region (78.0–1670 pg/m3, mean 458 pg/m3) than in many remote areas, lower than in developed regions, and comparable to levels in many developing country cities. Generally, the ∑11OPEs were higher in urban (105–1670 pg/m3, mean 538 pg/m3) than in suburban (78.0–1350 pg/m3, mean 388 pg/m3). Seasonal variations of OPEs in the air were more pronounced in Cambodia and Laos, especially for Triphenyl Phosphate (TPHP). Seasonal variations of ∑11OPEs in most regions correspond to changes in temperature and rainfall. Biomass burning may be also a factor in facilitating OPE emissions from biomass materials or soil into the atmosphere of Southeast Asia. The random forest analysis showed that among these, rainfall had the greatest effect on the seasonal variation of atmospheric OPE concentrations, followed by biomass burning and temperature. The inter-regional variation of ∑11OPEs in Southeast Asia was related to population and economic development in each region. Airflow trajectories indicated that the OPEs in this region were mainly from local sources. The health risk assessment revealed that the inhalation exposure risks of OPEs to the residents in the study areas were very low during the sampling period, but may be increasing.

Organophosphate ester additives and microplastics in benthic compartments from the Loire estuary (French Atlantic coast)

We report the first empirical confirmation of the co-occurrence of organophosphate esters (OPEs) additives and microplastics (MPs) in benthic compartments from the Loire estuary. Higher median concentrations of MPs (3387 items/kg dw), ∑13tri-OPEs (12.0 ng/g dw) and ∑4di-OPEs (0.7 ng/g dw) were measured in intertidal sediments with predominance of fine particles, and under higher anthropogenic pressures, with a general lack of seasonality. Contrarily, Scrobicularia plana showed up to 4-fold higher ∑tri-OPE concentrations in summer (reaching 37.0 ng/g dw), and similar spatial distribution. Polyethylene predominated in both compartments. Tris(2-ethylhexyl) phosphate (TEHP), its degradation metabolite (BEHP) and tris-(2-chloro, 1-methylethyl) phosphate (TCIPP) were the most abundant OPEs in sediments, while TCIPP predominated in S. plana. The biota-sediment accumulation factors suggest bioaccumulation potential for chlorinated-OPEs, with higher exposure in summer. No significant correlations were generally found between OPEs and MPs in sediments suggesting a limited role of MPs as in-situ source of OPEs.

Occurrence and potential risks of organophosphate esters in agricultural soils: A case study of Fuzhou City, Southeast China

Fifty agricultural soil samples collected from Fuzhou, southeast China, were first investigated for the occurrence, distribution, and potential risks of twelve organophosphate esters (OPEs). The total concentration of OPEs (ΣOPEs) in soil ranged from 1.33 to 96.5 ng/g dry weight (dw), with an average value of 17.1 ng/g dw. Especially, halogenated-OPEs were the predominant group with a mean level of 9.75 ng/g dw, and tris(1-chloro-2-propyl) phosphate (TCIPP) was the most abundant OPEs, accounting for 51.1% of ΣOPEs. The concentrations of TCIPP and ∑OPEs were found to be significantly higher (P < 0.05) in soils of urban areas than those in suburban areas. In addition, the use of agricultural plastic films and total organic carbon had a positive effect on the occurrence of OPE in this study. The positive matrix factorization model suggested complex sources of OPEs in agricultural soils from Fuzhou. The ecological risk assessment demonstrated that tricresyl phosphate presented a medium risk to land-based organisms (0.1 ≤ risk quotient < 1.0). Nevertheless, the carcinogenic and non-carcinogenic risks for human exposure to OPEs through soil ingestion and dermal absorption were negligible. These findings would facilitate further investigations into the pollution management and risk control of OPEs.

Occurrence, distribution, sources, and risk assessment of organophosphate esters in typical coastal aquaculture waters of China

This study monitored 20 organophosphate esters (OPEs) in water and sediment from three typical mariculture bases (Yunxi Marine Ranching (YX), Hangzhou Bay (HZB), and Zhelin Bay (ZLB)) and Meiliang Bay (MLB) of Taihu Lake in China, focusing on the spatial distribution and sources of OPEs. Moreover, the occurrence and risk of OPEs in fishes from ZLB were evaluated. The ∑OPE concentrations in waters followed the order MLB (591 ng/L) > YX (102 ng/L) > HZB (70.0 ng/L) > ZLB (37.4 ng/L), with tri(1-chloro-2-propyl) phosphate (TCIPP), triethyl phosphate (TEP), and tri(2-chloroethyl) phosphate (TCEP) being the dominant OPEs. Significantly higher ∑OPE concentrations were found in sediment in MLB compared to the other three areas with similar levels. The decreasing concentrations of OPEs from nearshore to offshore areas in HZB and MLB indicated that terrigenous input is the main source of OPEs. The even distribution of OPEs in YX and ZLB combined with PCA analysis suggested ship traffic or aquaculture activities are also potential sources. The ∑OPE concentrations in fishes ranged from 0.551–2.45 ng/g wet weight, with TCIPP, tri-phenyl phosphate (TPHP), and TCEP being the main OPEs. Hydrophobicity was a key factor affecting the sediment-water distribution coefficients and the bioaccumulation factors of OPEs. The human exposure to OPEs through consumption of fishes from ZLB had a low health risk.

Study of the Spatiotemporal Variations, Source Determination, and Potential Ecological Risk of Organophosphate Esters in Typical Coastal Tourist Resorts in China

Investigation of the environmental occurrence and behavior of organophosphate esters (OPEs) is very important and is becoming a hot topic in the academic community. In this study, 12 targeted OPEs in the water and sediment from 19 coastal tourist resorts in the Shandong Peninsula in China were analyzed to show their concentrations, spatial variations, and potential ecological risks. The results showed that the total concentrations of OPEs (ΣOPEs) were in the range of 18.52–3069.43 ng/L in the water and 3.20–568.76 ng/g in the sediment. The dominant OPEs in the water and sediment were tris (2-chloroisopropyl) phosphate (TCIPP), tris (2-chloroethyl) phosphate (TCEP), and triethyl phosphate (TEP). The OPE concentrations in the water were ranked as dry season &gt; normal season &gt; wet season. The sewage treatment plants near tourist resorts were important contributors to the level of OPEs in the water. Triphenyl phosphate (TPHP), tri-n-butyl phosphate (TNBP), and resorcinol-bis(diphenyl)phosphate (RDP) had a relatively higher ecological risk than other OPEs in the water samples. Industrial emissions might be the main source of OPEs in the coastal tourist resorts of Shandong Peninsula in China. The results of this study verified that OPEs occur in the water and sediment of coastal tourist resorts, and more attention should be given to the existence of OPEs and the safety of aquatic environments near coastal tourist resorts.

Organophosphate esters in rural wastewater along the Yangtze river Basin: Occurrence, removal efficiency and environmental implications

Organophosphate esters (OPEs) discharged from rural domestic wastewater were one of the important sources of OPEs in receiving water bodies, which has posed a potential threat to the ecological environment. However, very little information on the characteristics of OPEs in the rural domestic wastewater is available. Herein, the occurrence, removal efficiency and environmental implication of OPEs in rural domestic wastewater treatment facilities (RD-WWTFs) along the Yangtze River Basin were investigated. Results indicated that the median concentrations of ΣAlkyl-OPEs, ΣHalogenated-OPEs, ΣAryl-OPEs and the total OPE (ΣOPEs) in influents were 28.28, 99.25, 10.22 and 136.84 ng/L, while the median concentrations of them in effluents were 25.80, 141.86, 7.98 and 173.31 ng/L, respectively. Undoubtedly, halogenated OPEs were the most abundant in both influent and effluent, followed by alkyl and aryl OPEs, and they accounted for average proportions of 69.50%, 19.96%and 10.54% for influents, and 78.16%, 16.14%and 5.71% for effluents, respectively. Specifically, tris(2-chloroisopropyl) phosphate (TCPP, median: 55.17 ng/L in influents and 85.75 ng/L in effluents) was the dominant contributor to the ΣOPEs concentrations with average proportions of 37.75% and 47.33% for influents and effluents, respectively. Moreover, the concentration ranks for most OPEs except for aryl OPEs from high to low were upper reaches > lower reaches > middle reaches. However, negative values of tris(2-chloroethyl)phosphate (TCEP, −32.4%), TCPP (−55.4%) and tris(1,3-dichloroisopropyl) phosphate (TDCPP, −26.3%) were observed. The removal rates of alkyl OPEs (10–20%) and aryl OPEs (20–30%) were also not sufficient. Ecological risk values of ΣOPEs showed that there were 2.44% of high risk, 31.7% of moderate risk and 41.5% of low risk for effluents; while 0.00%, 48.8% and 46.3% were exhibited in high, moderate and low risk for influents, indicating that very slight reduction in risk was achieved by the RD-WWTFs.

Organophosphate esters (OPEs) in plastic food packaging: non-target recognition, and migration behavior assessment

Organophosphate esters (OPEs) are widely used as plasticizers in plastic food packaging; however, the migration of OPEs from plastic to food is largely unstudied. We do not even know the specific number of OPEs that exist in the plastic food packaging. Herein, an integrated target, suspect, and nontarget strategy for screening OPEs was optimized using ultrahigh-performance liquid chromatography–high-resolution mass spectrometry (UHPLC–HRMS). The strategy was used to analyze 106 samples of plastic food packaging collected in Nanjing city, China, in 2020. HRMS allowed full or tentative identification of 42 OPEs, of which seven were reported for the first time. Further, oxidation products of bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (AO626) in plastics were identified, implying that the oxidation of organophosphite antioxidants (OPAs) could be an important indirect source of OPEs in plastics. The migration of OPEs was examined with four simulated foods. Twenty-six out of 42 OPEs were detected in at least one of the four simulants, particularly isooctane, in which diverse OPEs were detected at elevated concentrations. Overall, the study supplements the list of OPEs that humans could ingest as well as provides essential information regarding the migration of OPEs from plastic food packaging to food.

Organophosphate esters in the seawater of the Bohai Sea: Environmental occurrence, sources and ecological risks

Organophosphate esters (OPEs) are widely distributed in surface water systems, but limited information was available on the spatial occurrence and ecological risks of OPEs in the Bohai Sea. In this study, 89 water samples in the Bohai Sea and the five surrounding rivers were investigated for the determination of 15 OPEs. The concentration of ∑15OPEs ranged from 373.20 to 2931.27 ng·L−1 in the river water and 137.81 to 2641.30 ng·L−1 in the seawater, with high levels of OPEs in Liaodong Bay. Tris(2-chloroethyl) phosphate (TCEP, 10– 92 %) and triethyl phosphate (TEP, 5– 64 %) were dominant for OPEs. The correlation analysis, principal component analysis and hierarchical cluster analysis suggested the conjunction of municipal wastewater via river input and maritime shipping was the main source of OPEs in the Bohai Sea. The ecological risk assessment indicated that the individual OPEs arise low ecological risks in the Bohai Sea, while medium ecological risks of ∑15OPEs are in minority river samples.

Organophosphate esters (OPEs) in the marine environment: Spatial distribution and profiles in French coastal bivalves

Organophosphate esters (OPEs), chemicals widely used in industrial production, electronics and domestic products, have become ubiquitous environmental contaminants. In this study, the levels and spatial distribution of 11 OPEs (aryl, alkyl and halogenated) were investigated in over 100 samples of filter-feeding bivalves collected yearly between 2014 and 2021 at sites of contrasted pressure along the French coasts. OPEs were found in virtually all samples, indicating their widespread spatial and temporal occurrence in coastal bivalves and the relevance of their biomonitoring. The median concentrations were between 0.4 (TMPP) and 4.9 ng g−1 dry weight (TCIPP), with TCIPP, TNBP and EHDPP found at the highest median values. TCEP and TBOEP were not frequently detected overall, but each year, the same sites showed repeatedly high concentrations. Structurally-related OPEs generally correlated, but the geographical distributions were not predictable from known anthropogenic pressures (population in the catchment area, industry), with little comparability with other hydrophobic contaminants. If the relation between sources of OPEs and bioaccumulated levels remains uncertain, local hotspots, rather than riverine/atmospheric transportation, could account for their geographical distribution. A systematic review of the levels of OPEs found in filter-feeding bivalves worldwide revealed comparable levels in our study with those reported elsewhere; however, the levels across and within (when available) studies generally spanned several orders of magnitude, indicating high spatial and temporal heterogeneity. In view of the growing concerns regarding OPEs, this study provides essential reference data for future studies of their occurrence on European coasts and supports the need for a more systematic (bio)monitoring of this class of contaminant.

Occurrence Distribution and Risk Assessment of Organophosphate Esters in A Typical Area of the Estuary in the Yellow River Basin

As a type of emerging pollutant, organophosphate esters (OPEs) have the characteristics of toxicity, persistence, and bioaccumulation. Due to their wide use in production and life, OPEs pose potential risks to ecosystems when they enter the environment. In this study, the concentrations of 14 species of OPEs in surface water were determined using UPLC-MS/MS, and the spatial distribution of the OPEs in the surface water of the estuary of the Yellow River basin was further analyzed. The pollution sources were analyzed using correlation analysis and principal component analysis, and the ecological risk was evaluated. The results indicated that the concentration of Σ14OPEs in surface water ranged from 183.81 to 1674.52 ng·L-1, with an average concentration of 638.25 ng·L-1. Tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propanyl) phosphate (TCPP) were the main OPEs. The Xiaoqing River flowing through the urban area differed from the main stream of the Yellow River and other branches in terms of OPEs composition characteristics, which showed a greater impact from human activities. The distribution of Σ14OPEs showed an obvious regional pattern, with a trend of increasing and then decreasing along the direction of the Yellow River inlet. The results of source analysis revealed that human activities such as industrial wastewater discharge from different industries, transportation, and atmospheric deposition were the sources of OPEs in surface water. The ecological risk assessment results indicated that TCEP posed a high risk to aquatic organisms in the main stream of the Yellow River, Xiaoqing River, and Zhimai River, and tri-n-butyl phosphate (TnBP) and triphenyl phosphate (TPhP) posed a low risk at some sites.

Occurrence, spatiotemporal variation, and ecological risks of organophosphate esters in the water and sediment of the middle and lower streams of the Yellow River and its important tributaries

Research on the environmental occurrence and behavior of organophosphate esters (OPEs) is very imperative. In this study, 12 targeted OPEs in the water and sediment samples collected from the middle and lower streams of the Yellow River (YR) and its tributaries during the dry, normal, and wet season were analyzed, to reveal their concentration, spatiotemporal variations, and ecological risks. The results indicated that the total concentration of OPEs (ΣOPE) ranged from 97.66 to 2433.30ng/L in water, and from 47.33 to 234.08ng/g in sediment. Tris(2-chloroethyl) phosphate (TCEP), tris(2-chloroisopropyl)phosphate (TCIPP), and triethyl phosphate (TEP) were the most abundant OPEs in the surface water and sediment. The OPEs levels in river water were ranked as the order of dry &gt;normal &gt;wet season. The ΣOPE concentrations in water and sediment were relatively high in the central and lower sections of the YR. The resorcinol-bis(diphenyl)phosphate (RDP) effectively transferred from the overlying water to the sediment. TCEP and RDP posed relatively higher ecological risk than other OPEs. Municipal and chemical industrial discharge might be sources of OPEs in the middle and lower streams of the YR.

Direct evidence of the important role of proteins in bioconcentration and biomagnification of PFASs in benthic organisms based on comparison with OPEs

Despite the wide acceptance that bioconcentration and biomagnification of per/polyfluoroalkyl substances (PFASs) is related to proteins in organisms, few direct evidences are available. Here, bioconcentration and biomagnification of 9 organophosphate esters (OPEs) and 16 PFASs, which have similar range of log Kow (octanol-water partitioning coefficient) values, were compared in the benthic food chain of biofilm-snail in Taihu Lake, China. The ∑OPEs level in water (150–23,036 ng/L) was significantly higher than ∑PFASs (57.3–351 ng/L). Although the logarithm of bioconcentration factors of both OPEs and PFASs in biofilm positively correlated with their log Kow, the slope of PFASs was 4 times of that of OPEs, which might be due to the strong interactions of PFASs with biofilm extracellular proteins. Additionally, PFASs exhibited distinctly greater biomagnification factors from biofilm to snails (3.09–17.8) than OPEs (0.39–3.48). Significant correlations between the concentrations and protein contents in snails were observed for most long-chain PFASs, but not for any OPEs. Multiple receptor models identified polyurethane foam (77.9 %) and food packaging/metal plating (56.9 %) were the primary sources of OPEs and PFASs in Taihu Lake, respectively. We provided strong and direct evidences that proteins facilitated bioconcentration and biomagnification of PFASs.

Dynamic variation and inhalation exposure of organophosphates esters and phthalic acid esters in face masks

The coronavirus pandemic (COVID-19) has posed a huge global health threat since December 2019. Wearing face masks is known as an effective measure for controlling the wide spread of COVID-19 and its variants. But on the other hand, face masks could be a potential source of organophosphate esters (OPEs) and phthalic acid esters (PAEs) as they are extensively added in masks. However, knowledge associated with the occurrence as well as inhalation risks of OPEs and PAEs in masks is limited. In this study, OPEs and PAEs were determined in different types of mask samples collected from the local market. OPEs and PAEs were detected in mask samples ranging from 36.7 to 855 ng/g, and from 251 to 3830 ng/g, respectively. Relatively lower OPEs and PAEs concentrations were observed in disposable mask for toddlers. Simulated inhalation experiment indicated that the mass loss of OPEs and PAEs was 136 and 3910 ng/mask in disposable masks, 71.9 and 763 ng/mask in disposable mask for toddlers, 924 and 1020 ng/mask in N95 mask after 12 h, respectively. Significantly negative correlations were exhibited between the decrement of OPEs in masks and the increment of OPEs in corresponding polyurethane foams (PUFs) during the course, elucidating OPEs released from masks could be well captured by PUFs. With regard to the variation over time, predominant OPE and PAE analogues showed semblable release and absorption tendency in mask and corresponding PUF. Inhalation exposure risk of OPEs and PAEs was estimated based on the increment of pollutants in PUF. The estimated daily intakes (EDIs), hazard index (HI) and carcinogenic risk (CR) were also calculated and they were within the threshold levels. This study provides the evidence of OPEs and PAEs releasing from the face masks during wearing and unveiled a potential source of OPEs and PAEs exposure to humans.