Organophosphorus flame retardants and plasticizers: sources, occurrence, toxicity and human exposure

Organophosphate Triesters and Their Transformation Products in Sediments of Mangrove Wetlands in the Beibu Gulf, South China Sea

As emerging pollutants, organophosphate esters (OPEs) have been reported in coastal environments worldwide. Nevertheless, information on the occurrence and ecological risks of OPEs, especially the related transformation products, in mangrove wetlands is scarce. For the first time, the coexistence and distribution of OP triesters and their transformation products in three mangrove wetlands in the Beibu Gulf were investigated using ultrasonication and solid-phase extraction, followed by UHPLC-MS/MS detection. The studied OPEs widely existed in all the sampling sites, with the total concentrations ranging from 6.43 ng/g dry weight (dw) to 39.96 ng/g dw and from 3.33 ng/g dw to 22.50 ng/g dw for the OP triesters and transformation products, respectively. Mangrove wetlands tend to retain more OPEs than the surrounding coastal environment. Pearson correlation analysis revealed that the TOC was not the sole factor in determining the OPEs' distribution, and degradation was not the main source of the transformation products in mangrove sediments in the Beibu Gulf. The ecological risks of selected OPEs for different organisms were also assessed, revealing a medium to high risk posed by OP diesters to organisms. The levels or coexistence of OPEs and their metabolites in mangroves need constant monitoring, and more toxicity data should be further studied to assess the effect on normal aquatic organisms.

Optimization and verification of selective removal of organophosphate esters from wastewater by molecularly imprinted adsorbent

Tributyl phosphate (TNBP), a new type of flame retardant, is an emerging pollutant and has been frequently detected in various matrices such as wastewater. Efficient removal of TNBP is critical for wastewater treatment. In this study, molecularly imprinted polymer (MIP) was prepared using precipitation polymerization for selective adsorption of TNBP. The results showed that MIP had a porous structure and formed effective imprinting cavities, which was primarily responsible for its superior adsorption ability. The adsorption of TNBP by MIP was carried out following both the pseudo-secondary kinetic model and the Langmuir isothermal adsorption model. MIP adsorbed TNBP rapidly and reached adsorption equilibrium within 30 min with 923 μmol g-1 at 298 K. The adsorption capacity and adsorption rate of MIP were respectively 2 and 5.49 times those of non-molecularly imprinted polymers. In addition, MIP could effectively counter disturbances from external parameters like temperature and pH, exhibiting strong environmental flexibility. MIP can specifically adsorb organophosphate esters, and can selectively adsorb TNBP under the interference of coexisting contaminants such as1,3-diphenylguanidine and isazofos. In actual bodies of water, MIP's highly selective adsorption of TNBP retains its advantage. The selective adsorption of MIP was mainly due to the common phosphate skeleton, and the specific substituent of organophosphate esters played an important role in the imprinting process. Hydrogen bonding might be involved in the polymerization process of TNBP with acrylamide and the adsorption process of TNBP by MIP.MIP exhibited good reuse efficiency, the total adsorption capacity decreased by no more than 25% after 7 reuse cycles. This study provides a simple and efficient method for selective removal of organophosphate from wastewater.

Cytotoxic and genotoxic effects of triphenyl phosphate on root tip cells of Allium cepa L

Triphenyl phosphate (TPhP) is a tri-ester of phosphoric acid and phenol. It is used in products such as polyvinyl chloride, hydraulic fluids, polymers, photographic films and printed circuit cards as a flame retardant. It is also widely used in consumer products like electric and electronic devices, textiles and building necessaries. TPhP can diffuse into its surrounding environment easily, because it does not form a chemical bond with polymeric materials. Therefore, bio-monitoring of such compounds is needed for possible environmental and human health effects. In this study, we evaluated genotoxicity and cytotoxicity of TPhP on Allium cepa on the cells of root tips. A 10 mg/mL stock solution of TPhP was dissolved in DMSO and dilutions of 2, 4, 6, 8 and 10 mg/mL was made in distilled water. Onion bulbs, rooted in test tubes, were exposed to these concentrations of TPhP for 24 h. Distilled water was used as a negative control, 0.7% hydrogen peroxide was used as positive control, and 0.5% DMSO was used as solvent control. Significant inhibition of onion root growth was observed following treatment with the 6, 8 and 10 mg/mL TPhP ranges in comparison with the negative and solvent control groups (p < 0.05). Furthermore, in the TPhP treatment groups, total chromosome aberration ratios were significantly high in comparison with the controls (p < 0.05). These results suggest that TPhP have cytotoxic and genotoxic effects on A. cepa root tips.

Astaxanthin activates the Nrf2/Keap1/HO-1 pathway to inhibit oxidative stress and ferroptosis, reducing triphenyl phosphate (TPhP)-induced neurodevelopmental toxicity

Triphenyl phosphate (TPhP) serves as a major organophosphorus flame retardant, and its induced neurodevelopmental toxicity has attracted widespread attention, but the mechanism remains unclear. In this study, we involved zebrafish to explore the new mechanism of TPhP inducing oxidative stress and ferroptosis to promote neurodevelopmental toxicity. The results suggested that TPhP affected the embryonic development, reduced the number of new neurons, and led to abnormal neural behavior in zebrafish larvae. TPhP also induced ROS accumulation, activated the antioxidant defense signal Nrf2 and Keap1, and significantly changed the activities of Acetylcholinesterase (AChE), Adenosine triphosphatase (ATPase) and glutathione S-transferase (GST). In addition, TPhP induced ferroptosis in zebrafish, which was reflected in the increase of Fe2+ content, the abnormal expression of GPX4 protein and genes related to iron metabolism (gpx4a, slc7a11, acsl4b, tfa, slc40a1, fth1b, tfr2, tfr1a, tfr1b and ncoa4). Astaxanthin intervention specifically inhibited ROS levels, and reversed SLC7A11 and GPX4 expression levels and Fe2+ metabolism thus alleviating ferroptosis induced by TPhP. Astaxanthin also partially reversed the activity of AChE, GST and the expression of neurodevelopmental-related genes (gap43, gfap, neurog1 and syn2a), so as to partially rescue the embryonic developmental abnormalities and motor behavior disorders induced by TPhP. More interestingly, the expression of mitochondrial apoptosis-related protein BAX, anti-apoptotic protein BCL-2, Caspase3 and Caspase9 was significantly altered in the TPhP exposed group, which could be also reversed by Astaxanthin intervention. In summary, our results suggested that TPhP exposure can induce oxidative stress and ferroptosis, thereby causing neurodevelopment toxicity to zebrafish, while Astaxanthin can partially reverse oxidative stress and reduce the neurodevelopmental toxicity of zebrafish larvae by activating Nrf2/Keap1/HO-1 signaling pathway.

Toxicity of TPhP on the gills and intestines of zebrafish from the perspectives of histopathology, oxidative stress and immune response

As an organophosphate ester (OPE), triphenyl phosphate (TPhP) has been frequently detected in aquatic environments, and its environmental risk has been widely studied. The gills and intestines are the most important part of the mucosal immune barrier in fish as the first line of defense against the invasion of harmful substances. TPhP is more abundant in the gill and intestine of fish. However, knowledge of the toxic effects and potential mechanisms of TPhP on the intestine and gill is limited. Herein, the adverse effects of TPhP (0.01, 0.1 and 1 mg/L) on the gills and intestines of zebrafish after 75 days of exposure were investigated from the perspectives of histology, oxidative stress and immune level. The histological results of exposed zebrafish showed that TPhP caused significant damage to gills and intestines. TPhP significantly increased the activities of the antioxidant enzymes catalase (CAT) and glutathione s-transferase (GST), inducing oxidative damage to lipids, proteins, and DNA. Meanwhile, the immune function of the gills and intestines was significantly influenced by TPhP, as evidenced by the upregulation of the expression of interleukin-1β (IL-1β) and interleukin-6 (IL-6), upregulation of the content of complement 3 (C3) and complement 4 (C4), and downregulation of the activity of lysozyme (LZM) and the content of immunoglobulin M (IgM). Oxidative stress and the immune response were more severe in the gills. These findings indicate that TPhP, a typical OPE, caused tissue damage in aquatic organisms by inducing oxidative stress and immune damage and has strong environmental toxicity.

Proposal for priority emerging pollutants in the Nakdong river, Korea: Application of EU watch list mechanisms

The Nakdong River, the longest in Korea, has received numerous pollutants from heavily industrialized and densely populated areas while being used as a drinking water source. A number of research have reported occurrences of emerging pollutants (EPs) in the river. The results requested efficient monitoring and systematic management strategies such as EU watch list under Water Framework Directive. The aim of this study is to propose a watch list through preliminary monitoring of the river and risk-based prioritization approach. As candidates for monitoring target, 632 substances were selected based on literature and database searches. Among them, 175 substances were subjected to target screening method whereas 457 were evaluated via suspect screening. A risk-based prioritization was applied to substances quantified through target screening based on concentrations, and a scoring-based prioritization was applied to substances tentatively identified through suspect screening. Sampling campaigns (n = 12) were conducted from October 2020 to September 2021, at 8 sampling sites along the river. As a result, 130 target substances were quantified above the LOQ. Among the 21 substances whose priority score was assigned through risk-based prioritization, telmisartan and iprobenfos were identified with very high environmental risk while candesartan, TBEP, imidacloprid, azithromycin and clotrimazole were classified with high or intermediate risk. As result of the scoring system for 39 tentatively identified substances, 6 substances (benzophenone, caprolactam, metolachlor oxanilic acid, heptaethylene glycol, octaethylene glycol and pentaethylene glycol), which were then confirmed with reference standards, showed a potential environmental risk. Those substances prioritized through target and suspect screening followed by scoring systems can be a subset for the watch list and potential targets for nationwide water quality monitoring program in the future.

The relationship of organophosphate flame retardants with hyperuricemia and gout via the inflammatory response: An integrated approach

BACKGROUND

Evidence regarding the relationships between organophosphate flame retardants (OPFRs) and hyperuricemia and gout as well as the underlying mechanisms remains scarce, but some evidence indicates that inflammation might play a key role.

OBJECTIVES

Using an integrated approach, we aim to elucidate the associations of urinary metabolite OPFRs (m-OPFRs) with hyperuricemia and gout.

METHODS

Cross-sectional analyses using data from the National Health and Nutrition Examination Survey were performed to reveal the associations. Adults with complete data on five m-OPFRs with high detection frequencies and outcomes were enrolled. We used multivariate logistic regression, restricted cubic spline (RCS), and Bayesian kernel machine regression (BKMR) methods to account for single, nonlinear, and joint effects. The mediating effect of the inflammatory response was also estimated. Moreover, adverse outcome pathways (AOPs) based on network analysis were further constructed to reveal the underlying mechanism.

RESULTS

Multivariate logistic models revealed that bis(2-chloroethyl) phosphate (BCEP) significantly increased risk of hyperuricemia (OR [95 % CI]: 1.165 [1.047, 1.296]) in the fully adjusted model. Elevated levels of bis(1-chloro-2-propyl) phosphate were associated with gout (OR [95 % CI]: 1.293 [1.015, 1.647]). No nonlinear relationship was observed in RCS. There was a positive association between mixed m-OPFRs and hyperuricemia risk in BMKR, with bis(1,3-dichloro-2-propyl) phosphate and BCEP being the main contributors (PIP > 0.5). We found that the inflammatory response significantly mediated the association between BCEP and hyperuricemia (P < 0.05). Network topology analysis identified seven genes and six phenotypes related to OPFR exposure and hyperuricemia. The AOP framework suggested that the inflammatory response, especially the activation of the TNF pathway, played a core role in the above relationships.

CONCLUSION

Our results first revealed that individual and mixed OPFRs were associated with hyperuricemia, in which the inflammatory response plays an important role. Further longitudinal studies are warranted to consolidate or refute our main findings.

Organophosphate esters in seawater and sediments from the low-latitude tropical sea

Little is known about the distribution, transport and fate of organophosphate esters (OPEs) in the low-latitude tropic sea. Fourteen OPEs were measured in seawater and sediments from the Pearl River Estuary (PRE) and South China Sea (SCS). The concentrations of OPEs in seawater and sediments ranged from 7.65-270 ng/L and 9.02-44.9 ng/g dw, respectively. The concentrations of OPEs in surface seawater from the PRE (93.4 ± 16.5 ng/L) were significantly higher than those in SCS (23.6 ± 2.17 ng/L, p < 0.001). OPEs in water from the PRE showed a decreasing trend from upstream to downstream. The salinity of water was an important factor to determine the concentrations of OPEs in the PRE. The annual input of OPEs from the PRE to the SCS was about 304 tons. The concentrations of OPEs in seawater column from the SCS decreased during 5-800 m and showed an increasing pattern from 800 m to 3400 m, indicating that OPEs can transport into deep seawater. TCPP was the most abundant OPEs in water and sediments from the PRE and TCEP was the predominant OPEs in the SCS. This work highlights long-range transport of OPEs by seawater to the deep sea environment.

Determinants of organophosphate esters exposure in pregnant women from East China

Organophosphate esters (OPEs) have been broadly used in various industrial and consumer products, resulting in global distribution and human exposure. Gestational exposure to OPEs may adversely affect the health of both pregnant women and their offspring. To better understand OPE exposure in pregnant women, our study determined eight urinary metabolites of major OPEs in pregnant women (n = 733) recruited at 12-16 weeks of gestation from Shanghai, China, and explored the determinants of OPE exposure among various sociodemographic characteristics, lifestyles, and dietary factors. Urinary metabolites of OPEs, including bis (1,3-dichloro-2-propyl) phosphate (BDCPP), bis (2-chloroethyl) phosphate (BCEP), bis (1-chloro-2-propyl) phosphate (BCIPP), dicresyl phosphate (DCP), diphenyl phosphate (DPP), dibutyl phosphate (DBP), bis (2-ethylhexyl) phosphate (BEHP), and bis (2-butoxyethyl) phosphate (BBOEP), exhibited a detection rate ranging from 69.30% to 99.32%. Multivariate linear regression models indicated that pregnant women who were multiparous, had a higher family income per capita, worked in white-collar jobs, and took nutritional supplements such as milk powder and fish oil tended to have higher urinary OPE metabolite concentrations. Besides, independent of sociodemographic characteristics and lifestyle factors, consumption of more aquatic products, soy products, pork, and puffed food, as well as drinking of purified tap water versus tap water, were associated with increased urinary OPEs metabolite concentrations. Our study demonstrated that OPE exposure was ubiquitous in pregnant women from Shanghai, and provided new insights into the potential factors influencing OPE exposure during pregnancy.

Methods for the characterisation of dermal uptake: Progress and perspectives for organophosphate esters

Organophosphate esters (OPEs) are a group of pollutants that are widely detected in the environment at high concentrations. They can adversely affect human health through multiple routes of exposure, including dermal uptake. Although attention has been paid to achieving an accurate and complete quantification of the dermal uptake of OPEs, existing evaluation methods and parameters have obvious weaknesses. This study reviewed two main categories of methodologies, namely the relative absorption (RA) model and the permeability coefficient (PC) model, which are widely used to assess the dermal uptake of OPEs. Although the PC model is more accurate and is increasingly used, the most important parameter in this model, the permeability coefficient (Kp), has been poorly characterised for OPEs, resulting in considerable errors in the estimation of the dermal uptake of OPEs. Thus, the detailed in vitro methods for the determination of Kp are summarised and sorted. Furthermore, the commonly used skin membranes are identified and the factors affecting Kp and corresponding mechanisms are discussed. In addition, the experimental conditions, conclusions, and available data on Kp values of the OPEs are thoroughly summarised. Finally, the corresponding knowledge gaps are proposed, and a more accurate and sophisticated experimental system and unknown Kp values for OPEs are suggested.

Uncovering the distribution patterns and origins of organophosphate esters (OPEs) in the Yellow River Estuary via high-resolution mass spectrometry

Limited information is available regarding the pollution status of organophosphate esters (OPEs) in the environment of the Yellow River estuary. Here, n = 51 sediment samples were collected from the Yellow River estuary in 2021, and further analyzed by using the integrated target, suspect, and feature fragment-dependent nontarget OPE screening strategy developed in our laboratory. Among the 30 target OPEs, 19 were detectable in at least one of the analyzed samples, with total concentrations (Σ19OPEs) ranging from of 41.4 to 1930 ng/g dry weight (dw). On the basis of an in-house suspect compound database, we further tentatively identified 11 suspect OPEs, and they were semi-quantified. Furthermore, four other interesting findings were observed and described as follows: 1) a statistically significant difference existed in the concentrations of OPEs in sediment samples between the lower reaches of the Yellow River (n = 5 samples), and the Yellow River estuary (n = 46 samples) (unpaired t-test, p < 0.001); 2) tris(2,4-di-tert-butylphenyl)phosphate (TDTBPP) exhibited the greatest concentrations (ranging from 30.7 to 1920 ng/g dw) among all OPEs detected in the sediment samples; 3) samples from the north of the Yellow River estuary had higher OPE concentrations than those from the south; and 4) a suspect screening strategy allowed us to identify a novel OPE structure (tert-butyl)phenyl (ethyne-oxidane) bis(2,4-di-tert-butylphenyl) phosphate (TPBDTP) that exhibited a highly positive correlation relationship with TDTBPP (r = 0.749; p < 0.001). Overall, this study provided evidence that OPEs (especially TDTBPP) were ubiquitous in the sediment environment of the Yellow River estuary; thus, we emphasize that continuous monitoring of OPE pollution should be conducted in this region.

Spatial trends and ecotoxic risk assessment of selected pharmaceuticals in sediments from Lake Victoria, Uganda, East Africa

Pharmaceutical residues in the aquatic environment are an emerging issue of global concern because of their effects on ecosystems including; antibacterial resistance development and endocrine disruption. Lake Victoria is the largest freshwater lake in Africa, and the second largest lake in the world. It is also the main source of the White Nile River, arguably the longest river in the world, flowing through South Sudan, Sudan, Ethiopia and Egypt, discharging into the Mediterranean Sea. However, its ecology is threatened by rapid industrialisation, urbanization, and increased agricultural activities, which have led to increased pollution via polluted runoffs. In this study, the occurrence of twenty-five pharmaceutical compounds (14 antibiotics, four anti-epileptic and antidepressant drugs, three analgesic and anti-inflammatory drugs, three beta-blockers, and one lipid regulator) was studied in 55 sediment samples obtained from the Ugandan sector of Lake Victoria, and their ecotoxic risk assessed. All the target compounds were quantifiable with levofloxacin (2-120 ng g-1 dm; dry mass), ciprofloxacin (3-130 ng g-1 dm) enoxacin (9-75 ng g-1 dm), ibuprofen (6-50 ng g-1 dm), metoprolol (1-92 ng g-1 dm) and propranolol (1-52 ng g-1 dm) being predominant. Murchison Bay, being the chief recipient of sewage effluents, municipal and industrial waste from Kampala city and its suburbs, had the highest levels. Ecotoxic risk assessment revealed that ciprofloxacin, levofloxacin, sulfamethoxazole, sulfamethazine, oxytetracycline, tetracycline, erythromycin, norfloxacin, ibuprofen, diclofenac, carbamazepine, atenolol, and metoprolol posed high toxic risks to sediment-dwelling organisms (risk quotients, RQ >1). This is the first study reporting concentrations and ecotoxic risks of pharmaceuticals in sediments of Lake Victoria, Uganda, and the whole of East Africa. Detection, identification and quantification of pharmaceuticals in Lake Victoria sediments is essential for gaining knowledge on their occurrence and fate which can ultimately be used to assist in constructing relevant policy and management recommendations.

Multi-pathway exposure assessment of organophosphate flame retardants in a southern Chinese population: Main route identification with compound-specificity

In this study, we conducted comprehensive organophosphorus flame retardant (PFR) exposure assessments of both dietary and non-dietary pathways in a rural population in southern China. Skin wipes were collected from 30 volunteers. Indoor and outdoor air (gas and particles), dust in the houses of these volunteers, and foodstuffs consumed by these volunteers were simultaneously collected. The total PFR concentrations in dust, gas, and PM2.5 varied from 53.8 to 5.14 × 105 ng/g, 0.528 to 4.27 ng/m3, and 0.390 to 16.5 ng/m3, respectively. The forehead (median of 1.36 × 103 ng/m2) and hand (median of 920 ng/m2) exhibited relatively high PFR concentrations, followed by the forearm (median of 440 ng/m2) and upper arm (median of 230 ng/m2). The PFR concentrations in the food samples varied from 0.0700 to 10.9 ng/g wet weight in the order of egg > roast duck/goose and vegetable > pork > chicken > fish. Tris(1-chloro-isopropyl) phosphate (TCPP) was the main PFR in the non-diet samples, whereas the profiles of PFR individuals varied by food type. Among the multiple pathways investigated (inhalation, dermal exposure, dust ingestion, and food ingestion), dermal absorption and dust ingestion were the predominant pathways for tris(2-chloroethyl) phosphate (TCEP) and bisphenol A-bis(diphenyl phosphate) (BDP), respectively, whereas dietary exposure was the most important route for other chemicals.

Organophosphate ester flame retardants and plasticizers in house dust and mental health outcomes among Canadian mothers: A nested prospective cohort study in CHILD

Organophosphate ester flame retardants and plasticizers (OPEs) are common exposures in modern built environments. Toxicological models report that some OPEs reduce dopamine and serotonin in the brain. Deficiencies in these neurotransmitters are associated with anxiety and depression. We hypothesized that exposure to higher concentrations of OPEs in house dust would be associated with a greater risk of depression and stress in mothers across the prenatal and postpartum periods. We conducted a nested prospective cohort study using data collected on mothers (n = 718) in the CHILD Cohort Study, a longitudinal multi-city Canadian birth cohort (2008-2012). OPEs were measured in house dust sampled at 3-4 months postpartum. Maternal depression and stress were measured at 18 and 36 weeks gestation and 6 months and 1 year postpartum using the Centre for Epidemiologic Studies for Depression Scale (CES-D) and Perceived Stress Scale (PSS). We used linear mixed models to examine the association between a summed Z-Score OPE index and continuous depression and stress scores. In adjusted models, one standard deviation increase in the OPE Z-score index was associated with a 0.07-point (95% CI: 0.01, 0.13) increase in PSS score. OPEs were not associated with log-transformed CES-D (β: 0.63%, 95% CI: -0.18%, 1.46%). The effect of OPEs on PSS score was strongest at 36 weeks gestation and weakest at 1 year postpartum. We observed small increases in maternal perceived stress levels, but not depression, with increasing OPEs measured in house dust during the prenatal and early postpartum period in this cohort of Canadian women. Given the prevalence of prenatal and postpartum anxiety and the ubiquity of OPE exposures, additional research is warranted to understand if these chemicals affect maternal mental health.

Spatial and temporal patterns of organophosphate Esters flame retardants and plasticizers in airborne particles over the Mediterranean sea

We studied the co-occurrence of OPEs and other constituents in atmospheric particles at the two edges of the Mediterranean Sea, under the influence of the transport of polluted air from Europe and dust from the Sahara. The highest OPE concentrations were observed during the summer period in the East Mediterranean and in spring for the NW Mediterranean. The total average atmospheric concentration of Σ6OPEs in the NW Mediterranean was 2103 ± 2020 pg m-3 (n = 23) with EHDPP and TCPP to be the predominant OPEs, accounting on average for 46% and 37% of the total Ʃ6OPEs concentrations, respectively. The average concentration of Σ6OPEs in East Mediterranean was 156.4 ± 170.3 pg m-3 (n = 67) with TCPP showing the highest concentration (116.1 ± 92.8 pg m-3), followed by TCEP (67.5 ± 55.8 pg m-3). In both areas, OPEs were mostly associated with fossil fuel combustion and road traffic, while the air masses from Saharan desert influenced the concentration of EHDPP, TCEP in NW Mediterranean and the TCEP concentration levels in the East Mediterranean. The total annual deposition of reported OPEs to the Mediterranean basin was estimated to be 584 tonnes, accounting for about 8.5% of the total deposited anthropogenic phosphorus.

Spatial and temporal variability and risk assessment of organophosphate esters in seawater and sediments of the Yangtze River estuary

Organophosphate esters (OPEs) as substitutes for PBDEs have been widely detected in the marine environment, while little is known about the pollution characteristics and variation of OPEs in estuarine environments with complex hydrodynamic conditions and land-based input. Yangtze River Estuary (YRE) is a typical highly urbanized and industrialized estuary, with a complex hydrological environment and geochemical behavior. This study found that the concentrations of OPEs in both seawater and sediments in the YRE were higher in spring than in summer. Alkyl OPEs were the first contributor, with TnBP and TiBP as the main components, where the contribution of alkyl OPEs had exceeded 75 % in both seawater and sediments in spring, and 60 % in summer seawater, and even 80 % in sediments. In spring, OPEs peaked in the central to southern region near the YRE. In summer, OPEs were mainly concentrated in the southern branch waterway and southern nearshore area of the YRE and showed a decreasing trend to the northeast. The OPEs in the sediments were mainly concentrated in the Yangtze River Mud Area (YREMA) and the Zhe-Min Coastal Mud Area (ZMCMA). Based on the fugacity model and principal component analysis, sediments could be released into the aquatic environment as an endogenous source, and exogenous sources were mainly municipal and industrial sewage discharge sources, urban and marine traffic discharge sources, and atmospheric deposition sources. The ecological risk analysis showed that the Σ14OPEs had exhibited a low to moderate ecological risk in the southern branch waterway and the south-central region offshore.

Associations of Organophosphate Ester Flame Retardant Exposures during Pregnancy with Gestational Duration and Fetal Growth: The Environmental influences on Child Health Outcomes (ECHO) Program

BACKGROUND

Widespread exposure to organophosphate ester (OPE) flame retardants with potential reproductive toxicity raises concern regarding the impacts of gestational exposure on birth outcomes. Previous studies of prenatal OPE exposure and birth outcomes had limited sample sizes, with inconclusive results.

OBJECTIVES

We conducted a collaborative analysis of associations between gestational OPE exposures and adverse birth outcomes and tested whether associations were modified by sex.

METHODS

We included 6,646 pregnant participants from 16 cohorts in the Environmental influences on Child Health Outcomes (ECHO) Program. Nine OPE biomarkers were quantified in maternal urine samples collected primarily during the second and third trimester and modeled as log 2 -transformed continuous, categorized (high/low/nondetect), or dichotomous (detect/nondetect) variables depending on detection frequency. We used covariate-adjusted linear, logistic, and multinomial regression with generalized estimating equations, accounting for cohort-level clustering, to estimate associations of OPE biomarkers with gestational length and birth weight outcomes. Secondarily, we assessed effect modification by sex.

RESULTS

Three OPE biomarkers [diphenyl phosphate (DPHP), a composite of dibutyl phosphate and di-isobutyl phosphate (DBUP/DIBP), and bis(1,3-dichloro-2-propyl) phosphate] were detected in > 85 % of participants. In adjusted models, DBUP/DIBP [odds ratio (OR) per doubling = 1.07 ; 95% confidence interval (CI): 1.02, 1.12] and bis(butoxyethyl) phosphate (OR for high vs. nondetect = 1.25 ; 95% CI: 1.06, 1.46), but not other OPE biomarkers, were associated with higher odds of preterm birth. We observed effect modification by sex for associations of DPHP and high bis(2-chloroethyl) phosphate with completed gestational weeks and odds of preterm birth, with adverse associations among females. In addition, newborns of mothers with detectable bis(1-chloro-2-propyl) phosphate, bis(2-methylphenyl) phosphate, and dipropyl phosphate had higher birth weight-for-gestational-age z -scores (β for detect vs. nondetect = 0.04 - 0.07 ); other chemicals showed null associations.

DISCUSSION

In the largest study to date, we find gestational exposures to several OPEs are associated with earlier timing of birth, especially among female neonates, or with greater fetal growth. https://doi.org/10.1289/EHP13182.

Establishment of an Integrated Nontarget and Suspect Screening Workflow for Organophosphate Diesters (Di-OPEs) and Identification of Seven Previously Unknown Di-OPEs in Food Contact Plastics

In this study, an innovative, integrated nontarget and suspect screening workflow was developed for identifying organophosphate diesters (di-OPEs) using high-resolution mass spectrometry. The workflow featured the utilization of 0.02% acetic acid as a mobile-phase additive, differentiated screening methods for alkyl and aryl di-OPEs, and a combination of electrospray negative ionization and positive ionization. Using this workflow, 18 di-OPEs were identified in the extracts of 75 food contact plastic (FCP) samples sourced from South China. Among these, six alkyl and one aryl di-OPEs were previously unknown (one unequivocal identification and six probable structures based on diagnostic evidence). (Semi)quantification revealed that bis(2,4-di-tert-butylphenyl) phosphate was the major di-OPE in FCPs, with a median concentration of 1079 ng/g (range: 23.4-158,414 ng/g). The migration efficiencies of di-OPEs from an FCP sample to four kinds of food simulants were between 2.58 and 54.3%. This study offered a useful workflow for the comprehensive profiling of di-OPEs in FCPs.

High-resolution mass spectrometry-based screening and dietary intake assessment of organophosphate esters in foodstuffs from South China

Organophosphate esters (OPEs) are a group of emerging contaminants with widespread environmental occurrence, yet research on their occurrence in foodstuffs is limited. We collected 100 foodstuff samples in South China using a market basket method, and analyzed food extracts for the presence of OPEs and organophosphite antioxidants (OPAs) by suspect and nontarget screening through high-resolution mass spectrometry. Our analysis resulted in the identification of 30 OPEs, comprised of 25 OPEs with a confidence level (CL) of 1 (unequivocal identification using standards) and five OPEs with CL = 2b (probable structure based on diagnostic evidence). Interestingly, 11 of these identified OPEs had not been previously reported in food. No OPA was identified. The occurrence of identified OPEs within the food samples was further investigated. The highest median concentration of OPEs in all food samples was reached by tris(2-chloroisopropyl) phosphate (TCPP) (1.55 ng/g ww, range < 0.74-12.0 ng/g wet weight (ww)). Cereals demonstrated the highest median concentration of the cumulative 30 OPEs. Tris(2-chloroethyl) phosphate (TCEP), TCPP, and triethyl phosphate (TEP) predominantly contributed to OPEs contamination in most food categories. Eight OPEs, namely TEP, tris(2-ethylhexyl) phosphate (TEHP), TCEP, triphenyl phosphate (TPhP), 2-ethylhexyl diphenyl phosphate (EHDPP), bis(2-ethylhexyl) phenyl phosphate (BEHPP), resorcinol bis(diphenyl phosphate) (RDP), and methyl diphenyl phosphate (MDPP) exhibited significantly higher concentrations in the processed group as compared to non-processed group, suggesting that food processing may result in contamination of these OPEs. The median sum of estimated dietary intake (ΣEDI) of all OPEs was determined to be 161 ng/kg body weight/day. Cereals (38.5 %) and vegetables (23.5 %) were the predominant food categories contributing to ΣEDI, and TEP (29.0 %), TCEP (20.2 %), and TCPP (18.3 %) were three major OPEs contributing to ΣEDI. This study for the first time offered a comprehensive overview of OPE species and revealed their occurrence in foodstuffs from South China.

Canadian high arctic ice core records of organophosphate flame retardants and plasticizers

Organophosphate esters (OPEs) have been used as flame retardants, plasticizers, and anti-foaming agents over the past several decades. Of particular interest is the long range transport potential of OPEs given their ubiquitous detection in Arctic marine air. Here we report 19 OPE congeners in ice cores drilled on remote icefields and ice caps in the Canadian high Arctic. A multi-decadal temporal profile was constructed in the sectioned ice cores representing a time scale spanning the 1970s to 2014-16. In the Devon Ice Cap record, the annual total OPE (∑OPEs) depositional flux for all of 2014 was 81 μg m-2, with the profile dominated by triphenylphosphate (TPP, 9.4 μg m-2) and tris(2-chloroisopropyl) phosphate (TCPP, 42 μg m-2). Here, many OPEs displayed an exponentially increasing depositional flux including TCPP which had a doubling time of 4.1 ± 0.44 years. At the more northern site on Mt. Oxford icefield, the OPE fluxes were lower. Here, the annual ∑OPEs flux in 2016 was 5.3 μg m-2, dominated by TCPP (1.5 μg m-2) but also tris(2-butoxyethyl) phosphate (1.5 μg m-2 TBOEP). The temporal trend for halogenated OPEs in the Mt. Oxford icefield is bell-shaped, peaking in the mid-2000s. The observation of OPEs in remote Arctic ice cores demonstrates the cryosphere as a repository for these substances, and supports the potential for long-range transport of OPEs, likely associated with aerosol transport.

Toxic trespassers: Uncovering phthalates and organophosphate flame retardants in children's rooms and their health implications

Organophosphate flame retardants (OPEs) and phthalates have garnered significant attention due to their widespread presence in indoor environments. Many recent investigations have reported extensive contamination of indoor dust, air, children's toys, and other environmental compartments with these chemicals. This research aimed to analyze OPEs and phthalates in air (PM10) and dust samples collected from the bedrooms of children (N = 30) residing in various households in Jeddah, Saudi Arabia. High mean levels (ng/g) of phthalates namely DEHP (1438600) and DnBP (159200) were found in indoor dust while TPhP (5620) was the major OPEs in indoor dust. Similarly, DEHP and DnBP were the predominant phthalates in PM10 samples, exhibiting mean levels of 560 and 680 ng/m3, respectively. However, TCPP was the main OPEs with average levels of 72 ng/m3 in PM10 samples. The majority of individual phthalates and OPEs were detected in 90-100 % of the dust samples, whereas in PM10 samples, their presence ranged from 25 % to 100 %. The concentrations of OPEs were notably greater than those of PBDEs and other BFRs previously reported in these samples, suggesting their broader use than alternative BFRs. The estimated long-term non-carcinogenic risk, hazardous index (HI) and daily exposure via dust for children was above threshold levels for DEHP. On the other hand, the cumulative risk of cancer was below the concerning levels. Further research is required to explore diverse groups of chemicals in indoor microenvironments particularly significant for children, such as kindergartens, primary schools, and their rooms at home.

A global meta-analysis of phthalate esters in drinking water sources and associated health risks

Phthalate esters (PAEs) are known as esters of phthalic acid, which are commonly used as plasticizers in the plastic industry. Due to the lack of chemical bonding with the polymer matrix, these compounds are easily separated from plastic products and enter the environment. To investigate the growth of concentration of PAEs like DBP (Dibutyl phthalate), DEP (Diethyl phthalate), DMP (Dimethyl phthalate), DIBP (Diisobutyl phthalate), and TPMBP (tris(2-methylbutyl) phosphate) in different water sources, a study from January 01, 1976, to April 30, 2021, was implemented via a global systematic review plus meta-analysis in which, 109 articles comprising 4061 samples, 4 water types, and 27 countries were included. Between various types of water sources, river water and lake water were the most contaminated resources with PAEs. Among all studies of PAEs, DBP and DEP with the values >15,573 mg L-1 have the highest average concentration and TPMBP with the value 0.002885 mg L-1 has the lowest average concentration in water sources. The most contaminated water sources with PAEs were in Nigeria and the least contaminated was in China. Besides, Monte-Carlo simulation indicated that for DMP and DEP minimum values that are lower than the acceptable limit are generated. However, most of the population (>75 %) is at risk for both adults and child cases. For DIBP and DBP the situation is much worse, the simulations not providing at least one case where the R index is lower than the acceptable limit of 1E-06.

Organophosphate esters (OPEs) and novel brominated flame retardants (NBFRs) in indoor dust: A systematic review on concentration, spatial distribution, sources, and human exposure

In recent years, the indoor exposure of organophosphate esters (OPEs) and novel brominated flame retardants (NBFRs) has received widespread attention worldwide. Using published data on 6 OPEs in 23 countries (n = 1437) and 2 NBFRs in 18 countries (n = 826) in indoor dust, this study systematically reviewed the concentrations, spatial distribution, sources and exposure risk of 8 flame retardants (FRs) worldwide. Tris(chloroisopropyl)phosphate (TCIPP) is the predominant FR with a median concentration of 1050 ng g-1 ΣCl-OPEs are significantly higher than Σnon-Cl-OPEs (p < 0.05). ΣOPEs in indoor dust from industrially-developed countries are higher than those from the countries lacking industrial development. Household appliances, electronics and plastic products are the main sources of non-Cl-OPEs and NBFRs, while interior decorations and materials contribute abundant Cl-OPEs in indoor dust. The mean hazard index (HI) of TCIPP for children is greater than 1, possibly posing non-cancer risk for children in some countries. The median ILCRs for 3 carcinogenic OPEs are all less than 10-6, suggesting no cancer risk induced by these compounds for both adults and children. This review helps to understand the composition, spatial pattern and human exposure risk of OPEs and NBFRs in indoor dust worldwide.

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

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

Distribution characteristics, source attribution, and health risk assessment of organophosphate esters in indoor and outdoor dust from various microenvironments in Beijing

The occurrence and profiles of organophosphate esters (OPEs) were studied in indoor and outdoor dusts from various microenvironments, including forty-seven outdoor dusts from green belts, roads, parks and residence areas, seventy-seven indoor dusts from private cars, print shops, taxis, furniture shops, offices, dormitories, shopping malls and residences house in different districts in Beijing. The total concentrations (Σ12OPEs) were eighteen times higher in indoor dusts (7.14 ×102 to 2.24 ×104 ng/g) than in outdoor dusts (36.0-1.56 ×103 ng/g). OPEs concentrations in samples from taxi and private cars were obviously higher than other indoor microenvironments. Both indoor and outdoor microenvironments also showed different compositional profiles of OPEs, indicating that polyurethane foam/building materials and hydraulic fluids/plastics were the greatest contributions in different microenvironments, with chlorinated alkyl phosphates (Cl-OPEs) being the predominant compound in both indoor dust (52.1-86.5%) and outdoor dust samples (42.6-81.3%). The uncertainty was reduced by Monte Carlo simulation, and the pollution levels of 50th and 95th percentiles were employed to calculate the average daily dosage, which was then used to calculate hazard quotient (HQ) for assessing the health risks to adults and children. Results showed that OPEs were safe even at extremely consumed concentration percentile (95th) in all groups.

Emerging and traditional organophosphate esters in office air from Hangzhou, East China: Seasonal variations, influencing factors and human exposure assessment

Eight emerging and six traditional organophosphate esters (OPEs) were investigated in office air from Hangzhou China with all the traditional OPEs and 5 out of 8 emerging OPEs detected. The median concentrations of ∑traditional OPEs and ∑emerging OPEs were 61,200 and 5.81 pg/m3, respectively. Butylphenyl diphenyl phosphate (BPDPP) and trisisopropyltrisphenyl phosphate (TIPPP) were observed for the first time in indoor air and Chinese office, respectively. The levels of ∑traditional OPEs decreased in the following order: summer > autumn > spring > winter. Conversely, no obvious trends were observed for emerging OPEs. ∑traditional OPEs (p < 0.001) and tri(chloroisopropyl) phosphate (TCIPP) (p < 0.01) concentrations were positively correlated with temperature. Interestingly, ∑emerging OPEs and the individual emerging OPEs analytes had no significant correlations with temperature (p > 0.05). ∑traditional OPEs, tris(2-chloroethyl) phosphate (TCEP) and TCIPP levels were significantly positively correlated with relative humidity (p < 0.05), while ∑emerging OPEs levels were negatively correlated with relative humidity (p < 0.05). Median intakes of traditional OPEs were estimated to be several orders of magnitude lower than the corresponding Reference Dose (RfD) values. The distinct environmental behaviors of emerging OPEs compared to traditional OPEs, coupled with the lack of established RfD values for them, underscore the need for their risk evaluations in future.

Occurrence, source apportionment, and ecological risk assessment of organophosphate esters in surface sediment from the Ogun and Osun Rivers, Southwest Nigeria

Organophosphate esters (OPEs) are synthetic chemicals widely used as e.g., flame retardants and plasticisers in various consumer products. Due to the toxicity of OPEs in aquatic ecosystems, exposure of fauna and flora to these compounds is of potential concern. In this study, the concentrations, profiles, sources, and ecological risk of eight OPEs were investigated in the sediments from the two major rivers in southwest Nigeria. Concentrations of ∑OPEs in surface sediments were in the range 13.1 - 2110 ng/g dry weight (dw) (median: 378 ng/g dw) in the Ogun River and 24.7-589 ng/g dw (median: 174 ng/g dw) in the Osun River. These concentrations are broadly within the range of those reported in surface sediment in previous studies conducted in other locations around the world. Tris (2-butoxyethyl) phosphate (TBOEP) was the dominant OPE in the sediment samples with a median concentration of 337 and 126 ng/g dw for the Ogun and Osun Rivers respectively, while tri-n-butyl phosphate (TnBP) was not detected in any sample. Excluding TBOEP, the chlorinated organophosphate esters: tris(2-chloroethyl) phosphate (TCEP), tris(2-chloro-propyl) phosphate (TCIPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) were the dominant OPEs in the Osun River, while the aryl-OPEs: triphenyl phosphate (TPHP), 2-ethylhexyl diphenyl phosphate (EHDPP), and tri-m-tolyl phosphate (TMTP) were dominant in the Ogun River. Under a median exposure scenario, moderate ecological risk was predicted from exposure to TCIPP in the Osun River. In contrast, under a high exposure scenario, concentrations of TDCIPP (risk quotient, RQ = 5.33-5.37) constituted a high ecological risk in both rivers, with moderate risks observed for TBOEP (RQ = 0.022-0.18) and TCIPP (RQ = 0.097 - 0.16). Therefore, the risk to aquatic organisms from concomitant exposure to mixtures of OPEs in freshwater ecosystems requires further investigation.

Hormonal Injustice: Environmental Toxicants as Drivers of Endocrine Health Disparities

The toll of multiple endocrine disorders has increased substantially in recent decades, and marginalized populations bear a disproportionate burden of disease. Because of the significant individual and societal impact of these conditions, it is essential to identify and address all modifiable risk factors contributing to these disparities. Abundant evidence now links endocrine dysfunction with exposure to endocrine-disrupting chemicals (EDCs), with greater exposures to multiple EDCs occurring among vulnerable groups, such as racial/ethnic minorities, those with low incomes, and others with high endocrine disease burdens. Identifying and eliminating EDC exposures is an essential step in achieving endocrine health equity.

Organophosphate ester (OPE) exposure among waste recycling and administrative workers in Denmark using silicone wristbands

In a recent estimate, 96 million tons of hazardous waste were produced in the European Union, most of which were handled among the member states. Organophosphate esters (OPEs) are applied as flame retardants and plasticizers and are present in many products, e.g., electronics, which end up in the hazardous waste stream upon disposal. Given the growing body of information suggesting potential adverse health effects of OPEs, waste recycling workers who handle hazardous waste could potentially be at risk of elevated exposure to these chemicals. Using silicone wristbands, we evaluated OPE exposure among waste recycling workers who handled hazardous waste and compared their exposure to that of administrative workers from the same waste companies. Wristbands were extracted and analyzed for six OPEs, which were all detected in >75% of wristbands. Overall, the sum of tris(2-chloroisopropyl) phosphate (∑TCIPP) isomers was the most abundant OPE across all wristbands collected within the study. In general, the sum of tri(methyl phenyl) phosphate isomers (∑TMPP) was elevated for all waste workers (10β = 7.9), whereas tri-n-butyl phosphate (TnBP), tris(1,3-dichloroisopropyl) phosphate (TDCIPP), and ∑TMPP were 3-12 times higher among those specifically handling electronic and hazardous waste compared to the administrative workers (p < 0.05). Repeated wristband measurements from the same worker had fair to good consistency in OPE concentrations (intraclass correlation coefficients = 0.54-0.77), except for the two most volatile chlorinated OPEs. Taken together, our results suggest that waste recycling workers who handle electronic and hazardous waste have significantly elevated exposure to OPEs, and efforts to reduce these exposures should be considered.

Endoplasmic reticulum stress participates in apoptosis of HeLa cells exposed to TPHP and OH-TPHP via the eIF2α-ATF4/ATF3-CHOP-DR5/P53 signaling pathway

Purpose

Triphenyl phosphate (TPHP) is a widely used organophosphate flame retardant, which can be transformed in vivo into diphenyl phosphate (DPHP) and 4-hydroxyphenyl phosphate (diphenyl) ester (OH-TPHP) through biotransformation process. Accumulation of TPHP and its derivatives in biological tissues makes it necessary to investigate their toxicity and molecular mechanism.

Methods

The present study evaluated the cellular effects of TPHP, DPHP, and OH-TPHP on cell survival, cell membrane damage, oxidative damage, and cell apoptosis using HeLa cells as in vitro model. RNA sequencing and bioinformatics analysis were conducted to monitor the differently expressed genes, and then RT-qPCR and Western bolt were used to identify potential molecular mechanisms and key hub genes.

Results

Results showed that OH-TPHP had the most significant cytotoxic effect in HeLa cells, followed by TPHP; and no significant cytotoxic effects were observed for DPHP exposure within the experimental concentrations. Biological function enrichment analysis suggested that TPHP and OH-TPHP exposure may induce endoplasmic reticulum stress (ERS) and cell apoptosis. The nodes filtering revealed that ERS and apoptosis related genes were involved in biological effects induced by TPHP and OH-TPHP, which may be mediated through the eukaryotic translation initiation factor 2α/activating transcription factor 4 (ATF4)/ATF3- CCAAT/ enhancer-binding protein homologous protein (CHOP) cascade pathway and death receptor 5 (DR5) /P53 signaling axis.

Conclusion

Above all, these findings indicated that ERS-mediated apoptosis might be one of potential mechanisms for cytotoxicity of TPHP and OH-TPHP.

Water, Water Everywhere, but Every Drop Unique: Challenges in the Science to Understand the Role of Contaminants of Emerging Concern in the Management of Drinking Water Supplies

The protection and management of water resources continues to be challenged by multiple and ongoing factors such as shifts in demographic, social, economic, and public health requirements. Physical limitations placed on access to potable supplies include natural and human-caused factors such as aquifer depletion, aging infrastructure, saltwater intrusion, floods, and drought. These factors, although varying in magnitude, spatial extent, and timing, can exacerbate the potential for contaminants of concern (CECs) to be present in sources of drinking water, infrastructure, premise plumbing and associated tap water. This monograph examines how current and emerging scientific efforts and technologies increase our understanding of the range of CECs and drinking water issues facing current and future populations. It is not intended to be read in one sitting, but is instead a starting point for scientists wanting to learn more about the issues surrounding CECs. This text discusses the topical evolution CECs over time (Section 1), improvements in measuring chemical and microbial CECs, through both analysis of concentration and toxicity (Section 2) and modeling CEC exposure and fate (Section 3), forms of treatment effective at removing chemical and microbial CECs (Section 4), and potential for human health impacts from exposure to CECs (Section 5). The paper concludes with how changes to water quantity, both scarcity and surpluses, could affect water quality (Section 6). Taken together, these sections document the past 25 years of CEC research and the regulatory response to these contaminants, the current work to identify and monitor CECs and mitigate exposure, and the challenges facing the future.

Organophosphate esters (OPEs) in a heavily polluted river in South China: Occurrence, spatiotemporal trends, sources, and phase distribution

In the past decade, organophosphate esters (OPEs) undergo rapid increase in production and use. Meanwhile, owing to their additive property, OPEs exhibit liability to escape from related products and therefore ubiquity in various environments. Moreover, numerous researches verify their bioavailability and negative effects on biota and human, hence their occurrence and associated risks have caught much concern, particularly those in aquatic systems. So far, however, OPEs in water are generally investigated as a whole, their phase distribution and behavior in waterbodies are incompletely characterized. We examined 25 OPEs in water (including dissolved and particulate phases), sediment, and sediment core samples from the Lian River, which flows through the Guiyu e-waste recycling zone and Shantou specific economic zone in South China. Compared to most global waterbodies, the Lian River showed high or ultrahigh OPE levels in both water and sediments, particularly in the reaches surrounded by e-waste recycling and plastic-related industries, which were the top two greatest OPE sources. Non-industrial and agriculture-related anthropogenic activities also contributed OPEs. Sediment core data suggested that OPEs have been present in waters in Guiyu since the 1960s and showed a temporal trend consistent with the local waste-recycling business. The phase distribution of OPEs in the Lian River was significantly correlated with their hydrophobicity and solubility. Owing to their wide range of physicochemical properties, OPE congeners showed significant percentage differences in the Lian River water and sediments. Generally, OPEs in water reflect their dynamic real-time inputs, while those in sediment signify their accumulative deposition, which is another cause of their phase distribution disparities in the Lian River. The physicochemical parameters of OPEs first imposed negative and then positive influences on their dissolved phase-sediment distribution, indicating the involvement of both the adsorption of dissolved OPEs and the deposition of particle-bound OPEs.

A multi-residue method for the analysis of organic pollutants released from atmospheric PM2.5 in simulated biological fluids: Inhalation bioaccessibility and bioavailability estimation

BACKGROUND

In recent decades, there has been a growing interest within the scientific community regarding the study of the fraction that could be released in simulated biological fluids to estimate in vitro bioaccessibility and bioavailability of compounds. Concerning particulate matter (PM), studies were essentially focused on metal (oid)s probably due to more complex methodologies needed for organic compounds, requiring extraction and pre-concentration steps from simulated fluids, followed by chromatographic analysis. Thus, the development of a simple and sensitive methodology for the analysis of multi-class organic compounds released in different inhalation simulated fluids would represent a great contribution to the field.

RESULTS

In this work, a methodology for the analysis of 49 organic pollutants, including 18 polycyclic aromatic hydrocarbons (PAHs), 12 phthalate esters (PAEs), 11 organophosphorus flame retardants (OPFRs), 6 synthetic musk compounds (SMCs) and 2 bisphenols released in simulated fluids from PM2.5 samples was developed. After a physiologically based extraction test (PBET) by using artificial lysosomal fluid (ALF) and a simulated body fluid (SBF, filling a dialysis membrane) to obtain in vitro inhalation bioaccessible and bioavailable fractions, respectively; compounds were determined by a vortex-assisted liquid-liquid extraction (VALLE) and a subsequent analysis by programmed temperature vaporization-gas chromatography-tandem mass spectrometry (PTV-GC-MS/MS). Experimental conditions concerning VALLE extraction (extraction time and amount of NaCl (g)) were optimized by using a central composite design (CCD), best MS/MS transitions were selected and matrix-matched calibration combined with use of labelled subrogate standards provided high sensitivity, minimization of matrix effects and recovering losses compensation.

SIGNIFICANCE

The successful validation results obtained for most of the compounds demonstrated the effectiveness of the proposed methodology for the analysis of multi-class organic pollutants released in ALF and SBF for inhalation bioaccessibility and bioavailability assessment, respectively. Furthermore, applicability of the method was proved by analysing 20 p.m.2.5 samples, being the proposed in vitro PBET dialyzability approach for assessing organic pollutant's inhalation bioavailability applied to PM2.5 samples for the first time.

Exposure to organophosphate flame retardants and plasticizers is positively associated with wheeze and FeNO and eosinophil levels among school-aged children: The Hokkaido study

Exposure to organophosphate flame retardants and plasticizers (PFRs) increases the risk of asthma and allergies. However, little is known about its association with type 2 inflammation (T2) biomarkers used in the management of allergies. The study investigated associations among urinary PFR metabolite concentrations, allergic symptoms, and T2 biomarkers. The data and samples were collected between 2017 and 2020, including school children (n = 427) aged 9-12 years living in Sapporo City, Japan, among the participants of "The Hokkaido Study on Environment and Children's Health." Thirteen urinary PFR metabolites were measured by LC-MS/MS. Allergic symptoms were assessed using the International Study of Asthma and Allergies in Childhood questionnaire. For T2 biomarkers, the peripheral blood eosinophil counts, fraction of exhaled nitric oxide level (FeNO), and serum total immunoglobulin E level were measured. Multiple logistic regression analysis, quantile-based g-computation (qg-computation), and Bayesian kernel machine regression (BKMR) were used to examine the associations between the health outcomes of the individual PFRs and the PFR mixtures. The highest concentration of PFR was Σtris(1-chloro-isopropyl) phosphates (ΣTCIPP) (Median:1.20 nmol/L). Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) was significantly associated with a high odds ratio (OR, 95%CI:1.36, 1.07-1.72) for wheeze. TDCIPP (OR, 95%CI:1.19, 1.02-1.38), Σtriphenyl phosphate (ΣTPHP) (OR, 95%CI:1.81, 1.40-2.37), and Σtris(2-butoxyethyl) phosphate (ΣTBOEP) (OR, 95%:1.40, 1.13-1.74) were significantly associated with increased odds of FeNO (≥35 ppb). ΣTPHP (OR, 95%CI:1.44, 1.15-1.83) was significantly associated with high eosinophil counts (≥300/μL). For the PFR mixtures, a one-quartile increase in all PFRs (OR, 95%CI:1.48, 1.18-1.86) was significantly associated with high FeNO (≥35 ppb) in the qg-computation model. The PFR mixture was positively associated with high FeNO (≥35 ppb) and eosinophil counts (≥300/μL) in the BKMR models. These results may suggest that exposure to PFRs increases the probability of asthma, allergies, and T2 inflammation.

Facile synthesis of spherical covalent organic frameworks for enrichment and quantification of aryl organophosphate esters in mouse serum and tissues

Here, an imine-linked-based spherical covalent organic framework (COF) was prepared at room temperature. The as-synthesized spherical COF served as an adsorbent in dispersive solid-phase extraction (dSPE), by its virtue of great surface area (1542.68 m2 /g), regular distribution of pore size (2.95 nm), and excellent stability. Therefore, a simple and high-efficiency dispersive solid phase extraction method based on a spherical COF coupled with high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was established to determine aryl organophosphate esters in biological samples. This approach displayed favorable linearity in the range of 10.0-1000.0 ng/L (r > 0.9989), a high signal enhancement factor (58.8-181.8 folds) with low limits of detection (0.3-3.3 ng/L). Moreover, it could effectively eliminate complex matrix interference to accurately extract seven aryl organophosphate esters from mouse serum and tissue samples with spiked recoveries of 82.0%-117.4%. The as-synthesized spherical COF has been successfully applied in sample preparation. The dSPE-HPLC-MS/MS method based on a spherical COF has potential application to study the pollutants' metabolism in vivo.

Cognitive Performance and Exposure to Organophosphate Flame Retardants in Children: Evidence from a Cross-Sectional Analysis of Two European Mother-Child Cohorts

The knowledge of the effects of organophosphate flame retardants on children's neurodevelopment is limited. The purpose of the present research is to evaluate the association between exposure to organophosphate flame retardants and children's neurodevelopment in two European cohorts involved in the Human Biomonitoring Initiative Aligned Studies. The participants were school-aged children belonging to the Odense Child Cohort (Denmark) and the PCB cohort (Slovakia). In each cohort, the children's neurodevelopment was assessed through the Full-Scale Intelligence Quotient score of the Wechsler Intelligence Scale for Children, using two different editions. The children's urine samples, collected at one point in time, were analyzed for several metabolites of organophosphate flame retardants. The association between neurodevelopment and each organophosphate flame retardant metabolite was explored by applying separate multiple linear regressions based on the approach of MM-estimation in each cohort. In the Danish cohort, the mean ± standard deviation for the neurodevelopment score was 98 ± 12; the geometric mean (95% confidence interval (95% CI)) of bis(1,3-dichloro-2-propyl) phosphate (BDCIPP) standardized by creatinine (crt) was 0.52 µg/g crt (95% CI = 0.49; 0.60), while that of diphenyl phosphate (DPHP) standardized by crt was 1.44 µg/g crt (95% CI = 1.31; 1.58). The neurodevelopment score showed a small, negative, statistically imprecise trend with BDCIPP standardized by crt (β = -1.30; 95%CI = -2.72; 0.11; p-value = 0.07) and no clear association with DPHP standardized by crt (β = -0.98; 95%CI = -2.96; 0.99; p-value = 0.33). The neurodevelopment score showed a negative trend with BDCIPP (β = -1.42; 95% CI = -2.70; -0.06; p-value = 0.04) and no clear association with DPHP (β = -1.09; 95% CI = -2.87; 0.68; p-value = 0.23). In the Slovakian cohort, the mean ± standard deviation for the neurodevelopment score was 81 ± 15; the geometric mean of BDCIPP standardized by crt was 0.18 µg/g crt (95% CI = 0.16; 0.20), while that of DPHP standardized by crt was 2.24 µg/g crt (95% CI = 2.00; 3.52). The association of the neurodevelopment score with BDCIPP standardized by crt was -0.49 (95%CI = -1.85; 0.87; p-value = 0.48), and with DPHP standardized by crt it was -0.35 (95%CI = -1.90; 1.20; p-value = 0.66). No clear associations were observed between the neurodevelopment score and BDCIPP/DPHP concentrations that were not standardized by crt. No clear associations were observed with bis(1-chloro-2-propyl) phosphate (BCIPP) in either cohort, due to the low detection frequency of this compound. In conclusion, this study provides only limited evidence of an inverse association between neurodevelopment and exposure to BDCIPP and DPHP. The timing of exposure and effect modification of other organophosphate flame retardant metabolites and other substances should be the subject of further investigations that address this scientific hypothesis.

Tributyl phosphate can inhibit the feeding behavior of rotifers by altering the axoneme structure, neuronal coordination and energy supply required for motile cilia

Organophosphorus flame retardants (OPFRs) are frequently detected in aquatic environments and can potentially amplify the food chain, posing a potential risk to organisms. Marine invertebrates have primitive nervous systems to regulate behavior, but how they respond to OPFRs that are potentially neurotoxic substances is unclear. This study assessed changes in the feeding behavior of rotifer Brachionus plicatilis exposed to alkyl OPFRs tributyl phosphate (TnBP) (0.376 nM, 3.76 and 22.53 µM) to elucidate the mechanism of behavioral toxicity. TnBP at 22.53 μM reduced the ingestion and filtration rates of rotifers for Chlorella vulgaris and Phaeocystis globosa in a 24-h test and altered rotifer-P. globosa population dynamics in 15-d coculture. Ciliary beat frequency was also reduced, and the expression of genes encoding the cilia axoneme was downregulated. TnBP could inhibit rotifer acetylcholinesterase activity by binding this protein and reduce the expression of the exocytotic membrane protein syntaxin-4, suggesting a disorder in nervous regulation of cilia beat. Moreover, TnBP induced abnormal shape and dysfunction of mitochondria, which caused insufficient energy required for ciliary movement. This study revealed diverse neurotoxicity mechanisms of TnBP, particularly as a potentially competing acetylcholinesterase ligand for aquatic invertebrates. Our research also provides a meaningful reference for OPFR-induced behavioral toxicity assessments.

Established and emerging organophosphate esters (OPEs) and the expansion of an environmental contamination issue: A review and future directions

The list of organophosphate esters (OPEs) reported in the environment continues to expand as evidenced by the increasing number of OPE studies in the literature. However, there remains a general dearth of information on more recently produced and used OPEs that are proving to be emerging environmental contaminants. The present review summarizes the available studies in a systematic framework of the current state of knowledge on the analysis, environmental fate, and behavior of emerging OPEs. This review also details future directions to better understand emerging OPEs in the environment. Firstly, we make recommendations that the current structural/practical abbreviations and naming of OPEs be revised and updated. A chemical database (CDB) containing 114 OPEs is presently established based on the suspect list from the current scientific literature. There are 12 established OPEs and a total of 83 emerging OPEs that have been reported in human and/or biota samples. Of the emerging OPEs more than 80% have nearly 100% detection frequencies in samples of certain environmental media including indoor air, wastewater treatment plants, sediment, and fish. In contrast to OPEs considered established contaminants, most emerging OPEs have been identified more recently due to the more pervasive use of high-resolution mass spectrometry (HRMS) based approaches and especially gas or liquid chromatography coupled with HRMS-based non-target analysis (NTA) of environmental sample fractions. Intentional/unintentional industrial use and non-industrial formation are sources of emerging OPEs in the environment. Predicted physical-chemical properties in silico of newer, molecularly larger and more oligomeric OPEs strongly suggest that some compounds such as bisphenol A diphenyl phosphate (BPA-DPP) are highly persistent, bioaccumulative and/or toxic. Limited information on laboratory-based toxicity data has shown that some emerging OPEs elicit harmful effects such as cytotoxicity, development toxicity, hepatotoxicity, and endocrine disruption in exposed humans and mammals. Established, and to a much lesser degree emerging OPEs, have also been shown to transform and degrade in biota and possibly alter their toxicological effects. Research on emerging OPE contaminants is presently limited and more study is warranted on sample analysis methods, source apportionment, transformation processes, environmental behavior, biomarkers of exposure and toxicity.

A critical review on the removal of toxic pollutants from contaminated water using magnetic hybrids

The persistence of organic/inorganic pollutants in the water has become a serious environmental issue. Among the different pollutants, dyes and heavy metal pollution in waterways are viewed as a global ecological problem that can have an impact on humans, plants, and animals. The necessity to develop a sustainable and environmentally acceptable approach to remove these toxic contaminants from the ecosystem has been raised. In the past two decades, rapid industrialization and anthropogenic activities in developed countries have aggravated environmental pollution. Industrial effluents that are discharged directly into the natural environment taint the water, which has a consequence for the water resources. Magnetic nanohybrids are broadly investigated materials used in the adsorption and photocatalytic degradation of poisonous pollutants present across water effluents. In the present review, the toxic health effects of heavy metals and dyes from the water environment have been discussed. This paper reviews the role of magnetic nanohybrids in the removal of pollutants from the water environment, providing an adequate point of view on their new advances regarding their qualities, connection methodologies, execution, and their scale-up difficulties.

Contamination characteristics and potential health risk of brominated flame retardants in paddy soils and rice plants around a typical e-waste recycling site in south China

Brominated flame retardants (BFRs) are widely used in various productions. As typical BFRs, polybrominated diphenyl ethers (PBDEs) are prohibited because of their toxicity and persistence. Some of the alternatives to PBDEs, new brominated flame retardants (NBFRs), have also been found in the environment and some have assigned hazardous properties and were categorized as persistent. In this study, a typical e-waste dismantling area was chosen as the study area, and the soil and rice samples were collected from the paddy fields around the circular economy park in Guiyu, China. The contaminations of PBDEs and NBFRs in soils and rice plants were detected, and the health risks associated with consumption and exposure to the environment were calculated as well. The concentrations of ∑PBDEs and ∑NBFRs in soil ranged from 283 to 928 μg/kg and 54.7-437 μg/kg, respectively. In rice plants, the majority of BFRs were concentrated in the following order: root > leaf > stem > grain. Additionally, only the PBT exhibited a stronger bioaccumulation ability in rice with the bioconcentration factors more than 1.00. The results of the health quotient calculation shown that BDE-47 might have an impact on people's health that only the HQ of BDE-47 in the soil was higher than 1.00, while there had no significant health risk in grain of BFRs. We believe that our work could assist researchers in investigating and revealing the human health effects of BFRs in soil and rice.

Organophosphate diesters (DAPs) and hydroxylated organophosphate flame retardants (HO-OPFRs) as biomarkers of OPFR contamination in a typical freshwater food chain

Organophosphate flame retardants (OPFRs) can rapidly biotransform into two types of metabolites in biota: (1) organophosphate diesters (DAPs) and (2) hydroxylated OPFRs (HO-OPFRs). Therefore, the levels of parent OPFRs alone are not sufficient to indicate OPFR pollution in biological organisms. This study analyzed 12 OPFR metabolites, including 6 DAPs and 6 HO-OPFRs, in a typical freshwater food chain consisted of crucian carp, catfish, mud carp, snakehead, and oriental river prawn. The total concentrations of OPFR metabolites were comparable to those of parent OPFRs, and ranged from 0.65 to 17 ng/g ww. Bis(2-butoxyethyl) 3'-hydroxy-2-butoxyethyl phosphate (14%-77%), di-n-butyl phosphate (DNBP) (6.7%-24%), bis(1-chloro-2-propyl) phosphate (BCIPP) (0.7%-35%), and 1-hydroxy-2-propyl bis(1-chloro-2-propyl) phosphate (BCIPHIPP) (6.0%-24%) were the major OPFR metabolites. Various aquatic species exhibited significant differences in their OPFR metabolite/parent ratios (MPR) (p < 0.05), indicating varying biotransformation potentials of different organisms for various OPFRs. The growth-independent accumulation of tri-n-butyl phosphate (TNBP), tris(chloro-2-propyl) phosphate (TCIPP), triphenyl phosphate, and 2-ethylhexyl diphenyl phosphate in mud carps could be explained by their biotransformation potential. A significant negative correlation was found between the concentration of bis(2-butoxyethyl) phosphate and δ15N values (p < 0.05), with a calculated trophic magnification factor (TMF) of 0.66. Significant positive correlations were observed between BCIPP and TCIPP (R2 = 0.25, p < 0.05), as well as between DNBP and TNBP (R2 = 0.30, p < 0.01), implying that these two DAPs could be used as biomarkers to quantitatively assess TCIPP and TNBP contamination in wild aquatic organisms.

PM2.5-Bound Organophosphate Flame Retardants in Hong Kong: Occurrence, Origins, and Source-Specific Health Risks

Organophosphate flame retardants (OPFRs) are emerging organic pollutants in PM2.5, which have caused significant public health concerns in recent years, given their potential carcinogenic and neurotoxic effects. However, studies on the sources, occurrence, and health risk assessment of PM2.5-bound OPFRs in Hong Kong are lacking. To address this knowledge gap, we characterized 13 OPFRs in one-year PM2.5 samples using gas chromatography-atmospheric pressure chemical ionization tandem mass spectrometry. Our findings showed that OPFRs were present at a median concentration of 4978 pg m-3 (ranging from 1924 to 8481 pg m-3), with chlorinated OPFRs dominating and accounting for 82.7% of the total OPFRs. Using characteristic source markers and positive matrix factorization, we identified one secondary formation and five primary sources of OPFRs. Over 94.0% of PM2.5-bound OPFRs in Hong Kong were primarily emitted, with plastic processing and waste disposal being the leading source (61.0%), followed by marine vessels (14.1%). The contributions of these two sources to OPFRs were more pronounced on days influenced by local pollution emissions (91.9%) than on days affected by regional pollution (44.2%). Our assessment of health risks associated with human exposure to PM2.5-bound OPFRs indicated a low-risk level. However, further source-specific health risk assessment revealed relatively high noncarcinogenic and carcinogenic risks from chlorinated OPFRs emitted from plastic processing and waste disposal, suggesting a need for more stringent emission control of OPFRs from these sources in Hong Kong.

Interactions of organophosphate flame retardants with human drug transporters

Organophosphate flame retardants (OPFRs) are environmental pollutants of increasing interest, widely distributed in the environment and exerting possible deleterious effects towards the human health. The present study investigates in vitro their possible interactions with human drug transporters, which are targets for environmental chemicals and actors of their toxicokinetics. Some OPFRs, i.e., tris(2-butoxyethyl) phosphate (TBOEP), tris(1,3-dichloroisopropyl) phosphate (TDCPP), tri-o-cresyl phosphate (TOCP) and triphenyl phosphate (TPHP), were found to inhibit activities of some transporters, such as organic anion transporter 3 (OAT3), organic anion transporting polypeptide (OATP) 1B1, OATP1B3, organic cation transporter 2 (OCT2) or breast cancer resistance protein (BCRP). These effects were concentration-dependent, with IC50 values ranging from 6.1 µM (for TDCPP-mediated inhibition of OCT2) to 51.4 µM (for TOCP-mediated inhibition of BCRP). OPFRs also blocked the transporter-dependent membrane passage of endogenous substrates, notably that of hormones. OAT3 however failed to transport TBOEP and TPHP. OPFRs additionally repressed mRNA expressions of some transporters in cultured human hepatic HepaRG cells, especially those of OAT2 and OCT1 in response to TOCP, with IC50 values of 2.3 µM and 2.5 µM, respectively. These data therefore add OPFRs to the expanding list of pollutants interacting with drug transporters, even if OPFR concentrations required to impact transporters, in the 2-50 µM range, are rather higher than those observed in humans environmentally or dietarily exposed to these chemicals.

Pollution characteristics, distribution, and source analysis of carbazole and polyhalogenated carbazoles in coastal areas of Bohai Bay, China

Polyhalogenated carbazoles (PHCZs) are a class of emerging environmental contaminants formed by the substitution of hydrogen on carbazole (CZ) benzene rings with halogens (Cl, Br, I) with potential dioxin-like toxicity, and they have been frequently detected in various environmental media and organisms recently. Nevertheless, co-research of CZ/PHCZs with PAHs is very limited. In addition, I-PHCZs, which are believed to be much more toxic than CZ, Cl-PHCZs and Br-PHCZs, have a few data in sediments previously. The concentration and distribution of CZ/PHCZs and PAHs were analyzed in 18 surface sediments of Bohai Bay, China. There is a significant correlation (R = 0.64, P＜0.05) between PHCZs and PAHs, and principal component analysis (PCA) also indicating that they may have a certain similarity in origin. Additionally, total CZ and PHCZs was up to 230.57 ng/g dw in the studied samples, which was approximately 1-2 orders of magnitude lower than PAHs and other common persistent organic pollutants (POPs). The compositions of the CZ/PHCZs in our study were dominated by CZ (2.74-18.28, median 2.92 ng/g dw), 3,6-dichlorocarbazole (n.d-6.78, median 0.97 ng/g dw) and 3,6-iodocarbazole (n.d-12.68, median 1.65 ng/g dw). Results of this study discovered the varying origins of CZ and PHCZs and/or a complexity of anthropogenic influences and natural sources processes, and revealed a wide distribution of CZ/PHCZs across the studied. Moreover, more attention should be paid by comparing CZ/PHCZs with other widely distributed POPs.

Distribution and transformation of organophosphate esters in moving bed biofilm reactor

A moving bed biofilm reactor (MBBR) process in wastewater treatment plants (WWTPs) uses plastic carriers, called biofilm carrier, to increase their treatment efficiency. Biofilm carrier is made up of plastic, containing the OPEs as flame retardants or plasticizers, so OPEs in biofilm carrier are possible to release from WWTPs to the river. This study investigated the effect of the MBBR process in WWTP on aquatic environments, focusing on OPEs. OPE eluted from the biofilm carrier by leaching test was tris(2-chloroethyl) phosphate (TCEP), and the concentration of the effluent compared to the influent was increased in the WWTP of the MBBR process. 3609 mg/day of TCEP would be discharged into the water using the second-order model with rate constant [Formula: see text] = 0.000451 (ng L-1)-1 h-1, which is the most suitable for the leaching concentration of TCEP. It was identified that TCEP in biofilm carrier was transformed into oxidative dechlorinated compounds and oxidative compounds by microorganisms in the bioreactor. As a result of the study, it was confirmed that not only TCEP but also transformation products of TCEP emitted into the water from the MBBR process of WWTP.

Simultaneous screening of 33 restricted substances in polymer materials using pyrolysis/thermal desorption gas chromatography-mass spectrometry

The purpose of this study was to offer a quick and efficient method to screen for multiple restricted additives in polymer materials. A solvent-free pyrolysis gas chromatography-mass spectrometry method was developed to simultaneously screen 33 restricted substances, comprising 7 phthalates, 15 bromine flame retardants, 4 phosphorus flame retardants, 4 ultraviolet stabilizers, and 3 bisphenols. The pyrolysis technique and temperatures affecting additive desorption were studied. Under optimized conditions, the instrument sensitivity was confirmed using in-house reference materials at concentrations of 100 mg/kg and 300 mg/kg. The linear range was between 100 and 1000 mg/kg in 26 compounds, and in the other compounds it was between 300 and 1000 mg/kg. In this study, in-house reference materials, certified reference materials, and proficiency testing samples were used for method verification. The relative standard deviation of this method was less than 15%, and recoveries ranged from 75.9 to 107.1% for most of the compounds, with a few exceeding 120%. Furthermore, the screening method was verified with 20 plastic products used in daily life and 170 recycled plastic particle samples from imports. The experimental results showed that phthalates were the main additives in plastic products, and among 170 recycled plastic particle samples, 14 samples were found to contain restricted additives. The main additives in recycled plastics were bis(2-ethylhexyl) phthalate, di-iso-nonyl phthalate, hexabromocyclododecane, and 2,2',3,3',4,4',5,5',6,6'-decabromodiphenyl ether at concentrations between 374 and 34785 mg/kg, except for some results that exceeded the maximum measured value of the instrument. Compared with traditional methods, an important advantage is that this method simultaneously tests for 33 additives without sample pretreatment, covering a variety of additives limited by laws and regulations, and therefore can provide more comprehensive and thorough inspections.

Deep mining of reported emerging contaminants in China's surface water in the past decade: Exposure, ecological effects and risk assessment

The identification and management of high-risk contaminants have raised great concern from governments. Facing the growing amount of data on the occurrence of emerging contaminants (ECs) in surface water, a deep mining and quality control strategy was developed to integrate data on all reported ECs in Chinese surface water over the past decade, and an exposure and effect database was further built. In addition, multilevel risk characterization was carried out to prioritize high-risk areas, contaminants and endpoints. A total of 1038 ECs, mainly pharmaceutical and personal care products (PPCPs) and industrial chemicals, were curated, with concentrations ranging from 0.02 pg/L to 533 µg/L. For individual risk, all the provinces had acceptable risks except for Henan, which was characterized with a medium chronic risk. Nine ECs, including 4-nonylphenol and estrone, dominated individual risks. Conversely, for multisubstance risk, 76.20% and 73.87% of aquatic organisms were affected acutely and chronically at the national level, with acute and chronic risks exceeding the safety threshold of 5% in 11 and 19 provinces, respectively. Nineteen ECs, including sitosterol and chyfluthrin, dominated the multisubstance risk. In addition, 9 MoAs mainly inducing electron transfer inhibition, neurotoxicity and narcosis toxicity are high-risk endpoints. The study revealed the ecological risk status and key risk entities of Chinese surface waters, which provided the latest data to support the control of ECs in China.

Levels of organophosphate flame retardants and their metabolites among 391 volunteers in Taiwan: difference between adults and children

Background

Organophosphate flame retardants (OPFRs) are ubiquitous in the environment. The compositions and concentrations of different OPFRs metabolites vary in different environments depending on different human activities. The objective of the present study was to evaluate the exposure of different age groups to OPFRs in Taiwan.

Methods

Volunteers provided urine samples and responded to questionnaires including demographic factors, underlying disease, lifestyle information, and occupation from October 2021 to January 2022. OPFR measurements were performed using a Waters Acquity Ultra-Performance Liquid Chromatography system coupled with a Waters Xevo TQ-XS mass spectrometer.

Results

A total of 391 volunteers (74 children and 317 adults) were enrolled in this study. The concentrations (presented as μg/g creatinine) of bis(1,3-dichloro-2-propyl) phosphate (BDCPP, p = 0.029) and tri-n-butyl phosphate (TNBP, p = 0.008) were higher in the adult group, while the concentrations of bis-2-chloroethyl phosphate (BCEP, p = 0.024), diphenyl phosphate (DPHP, p < 0.001), tris(1,3-dichloro-2-propyl) phosphate (TDCPP, p = 0.009), and Tris(2-butoxyethyl) phosphate (TBEP, p = 0.007) were higher in the child group. Compared with school age children (>6 years), the concentration of di(2-n-butoxyethyl) phthalate (DBEP, 1.14 vs. 0.20 μg/g creatinine, p = 0.001), DPHP (1.23 vs. 0.54 μg/g creatinine, p = 0.036), TBEP (1.63 vs. 0.29 μg/g creatinine, p < 0.001), and the sum of OPFR metabolites (ΣOPFRs, 6.58 vs. 2.04 μg/g creatinine, p < 0.001) were statistically higher in preschool-aged children. After adjusting for confounding factors, pre-school age [odds ratio (OR): 4.579, 95% confidence interval (CI): 1.389-13.115] and current smoker (OR: 5.328, 95%CI: 1.858-14.955) were independently associated with the risk of ΣOPFRs higher than 90 percentile.

Conclusion

This study revealed the distribution of different OPFRs metabolites in children and adults. DBEP, DPHP, TBEP, and ΣOPFR were higher in preschool-aged children. Pre-school age and current smoking status were independent risk factors for ΣOPFRs higher than 90 percentile.

Nontarget Identification of Novel Organophosphorus Flame Retardants and Plasticizers in Rainfall Runoffs and Agricultural Soils around a Plastic Recycling Industrial Park

Plastic recycling and reprocessing activities may release organophosphate ester (OPE) flame retardants and plasticizers into the surrounding environment. However, the relevant contamination profiles and impacts remain not well studied. This study investigated the occurrence of 28 OPEs and their metabolites (mOPEs) in rainfall runoffs and agricultural soils around one of the largest plastic recycling industrial parks in North China and identified novel organophosphorus compounds (NOPs) using high-resolution mass spectrometry-based nontarget analysis. Twenty and twenty-seven OPEs were detected in runoff water and soil samples, with total concentrations of 86.0-2491 ng/L and 2.53-199 ng/g dw, respectively. Thirteen NOPs were identified, of which eight were reported in the environment for the first time, including a chlorine-containing OPE, an organophosphorus heterocycle, a phosphite, three novel OPE metabolites, and two oligomers. Triphenylphosphine oxide and diphenylphosphinic acid occurred ubiquitously in runoffs and soils, with concentrations up to 390 ng/L and 40.2 ng/g dw, respectively. The downwind areas of the industrial park showed elevated levels of OPEs and NOPs. The contribution of hydroxylated mOPEs was higher in soils than in runoffs. These findings suggest that plastic recycling and reprocessing activities are significant sources of OPEs and NOPs and that biotransformation may further increase the ecological and human exposure risk.

Higher ecological risks and lower bioremediation potentials identified for emerging OPEs than legacy PCBs in the Beibu Gulf, China

The production and use of organophosphate esters (OPEs) as substitutes for traditional halogenated flame retardants is increasing, resulting in greater global concern related to their ecological risks to marine environments. In this study, polychlorinated biphenyls (PCBs) and OPEs, representing traditional halogenated and emerging flame retardants, respectively, were studied in multiple environmental matrices in the Beibu Gulf, a typical semi-closed bay in the South China Sea. We investigated the differences in PCB and OPE distributions, sources, risks, and bioremediation potentials. Overall, the concentrations of emerging OPEs were much higher than those of PCBs in both seawater and sediment samples. Sediment samples from the inner bay and bay mouth areas (L sites) accumulated more PCBs, with penta- and hexa-CBs as major homologs. Chlorinated OPEs were prevalent in both seawater and sediment samples from the L sites, whereas tri-phenyl phosphate (TPHP) and tri-n-butyl phosphate (TNBP) were predominant at the outer bay (B sites) sediment samples. Source identification via principal component analysis, land use regression statistics, and δ13C analysis indicate that PCBs were mainly sourced from the atmospheric deposition of sugarcane and waste incineration, whereas sewage inputs, aquaculture, and shipping activity were identified as sources of OPE pollution in the Beibu Gulf. A half-year sediment anaerobic culturing experiment was performed for PCBs and OPEs, and the results only exhibited satisfactory dechlorination for PCBs. However, compared with the low ecological risks of PCBs to marine organisms, OPEs (particularly trichloroethyl phosphate (TCEP) and TPHP) exhibited low to medium threats to algae and crustaceans at most sites. Given their increasing usage, high ecological risks, and low bioremediation potential in enrichment cultures, pollution by emerging OPEs warrants close attention.