Comparison of the mechanisms of estrogen disrupting effects between triphenyl phosphate (TPhP) and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP).

As the typical aryl-organophosphate flame retardants (OPFRs), triphenyl phosphate (TPhP) and tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) were reported to be estrogen disruptors. However, estrogen receptor α (ERα) binding experiments could not explain their biological effects. In this study, their action on ERα, G protein-coupled estrogen receptor (GPER) and the synthesis of 17ß-estradiol (E2) were investigated using in vitro assays and molecular docking. The results showed that TPhP acted as an ERα agonist and recruited steroid receptor co-activator 1 (SRC1) and 3 (SRC3), which was found for the first time. Unlike TPhP, TDCIPP acted as an ERα antagonist. However, both TPhP and TDCIPP activated the estrogen pathway by GPER in SKBR3 cells which were lack of ERα. Although molecular docking results revealed that both TPhP and TDCIPP could dock into ERα and GPER, their substituent groups and combination mode might affect the receptor activation. In addition, by using estrogen biosynthesis assay in H295R cells, both of TPhP and TDCIPP were found to promote E2 synthesis and E2/T ratio involving their different alteration on levels of progesterone, testosterone and estrone, and expression of various key genes. Our data proposed estrogen-disrupting mechanism frameworks of TPhP and TDCIPP. Moreover, our results will contribute to future construction of adverse outcome pathway (AOP) framework of endocrine disruptors.

Water pollutant discharge permit allocation based on DEA and non-cooperative game theory.

Against the background of the ecological civilization system reform in the new era, the appropriate allocation of water pollutant discharge permits is an important policy for controlling the amount of wastewater discharge. Traditional allocation methods have disadvantages, such as high additional costs, an unfair allocation scheme, and market distortion. In the present study, a fixed-cost allocation model based on data envelopment analysis (DEA) and the Nash non-cooperative game theory is employed to allocate water pollutant discharge permits of totally 31 provinces in China from 2008 to 2017. The allocation scheme considers environmental efficiency. The results demonstrate regional differences in the allocation of water pollutant discharge permits. The eastern region has abundant allocations. The northeastern and central regions have insufficient allocations. Besides, the western region has a significant shortage of allocations. It indicates the higher the utilization efficiency of the water pollutant discharge permits, the higher the region's sustainable development is. Based on the analysis, we propose guidelines for industrial wastewater discharge reduction.

Fish forewarning of comprehensive toxicity in water environment based on Bayesian sequential method.

Environmental impact of pollutants can be analyzed effectively by acquiring fish behavioral signals in water with biological behavior sensors. However, a variety of factors, such as the complexity of biological organisms themselves, the device error and the environmental noise, may compromise the accuracy and timeliness of model predictions. The current methods lack prior knowledge about the fish behavioral signals corresponding to characteristic pollutants, and in the event of a pollutant invasion, the fish behavioral signals are poorly discriminated. Therefore, we propose a novel method based on Bayesian sequential, which utilizes multi-channel prior knowledge to calculate the outlier sequence based on wavelet feature followed by calculating the anomaly probability of observed values. Furthermore, the relationship between the anomaly probability and toxicity is analyzed in order to achieve forewarning effectively. At last, our algorithm for fish toxicity detection is verified by integrating the data on laboratory acceptance of characteristic pollutants. The results show that only one false positive occurred in the six experiments, the present algorithm is effective in suppressing false positives and negatives, which increases the reliability of toxicity detections, and thereby has certain applicability and universality in engineering applications.

In Vitro Immunotoxicity of Organophosphate Flame Retardants in Human THP-1-Derived Macrophages.

Scarce attention has been paid to the immunotoxicity of organophosphate flame retardants (PFRs), which poses a challenge to the systematic assessment of their health risks. In this study, a battery of in vitro immunotoxicity screening assays, including adhesion, phagocytosis, and 48 cytokine/chemokine production, was measured after exposing THP-1-derived macrophages to six selected common PFRs (TPHP, TDCPP, TNBP, TOCP, TCEP, and TBOEP) at a noncytotoxic concentration (≤50 µM). Our results showed that TPHP and TBOEP partially attenuated the adhesion and phagocytosis of the THP-1 mφs and that TDCPP caused a functional loss of phagocytosis, implying the potential immunosuppression. In contrast, TNBP and TOCP may cause an immunostimulation by significantly promoting cell adhesion and enhancing phagocytic efficiency. Additionally, the results from a cytokine/chemokine secretion analysis revealed the proinflammatory properties of TDCPP, TPHP, and TBOEP. TOCP was thought to disrupt the inflammatory balance by inhibiting both proinflammatory and antiinflammatory cytokines. TCEP showed no effect on adhesion or phagocytosis and little modulation of cytokine release at this experimental concentration. Overall, this study supports that PFRs can be immunotoxic to macrophages in different ways and provides evidence for developing more sensitive in vitro immunotoxicity bioassay methods.

The steroid receptor coactivator 1 (SRC1) and 3 (SRC3) recruitment as a novel molecular initiating event of 4-n-nonylphenol in estrogen receptor α-mediated pathways.

Recently, the action of steroid receptor coactivators (SRCs) has been recognized to be an important molecular initiating event (MIE) in estrogenic adverse outcome pathways (AOPs). However, the role of SRCs in the molecular mechanisms of many highly concerned environmental estrogens remains poorly understood. In this study, the widely studied environmental estrogen, 4-n-nonylphenol (4-n-NP), was used as a typical pollutant to study SRCs recruitment in its estrogenic effects. In MCF7 cell proliferation (E-SCREEN) assay and MVLN cell assay, 4-n-NP showed significant estrogenic potency that involved an increase in estrogen receptor α (ERα), SRC1 and SRC3 transcript levels. Moreover, 4-n-NP was found to induce estrogen response element (ERE)-mediated activity via ERα in MVLN cells. To investigate the mechanism by which SRCs recruitment is induced by 4-n-NP-ERα, a coactivators recruitment assay was performed, and the results showed that 4-n-NP-ERα recruited both SRC1 and SRC3, whereas it failed to recruit SRC2. Similarly, it had no interaction with SRC2 in the ERα-SRC2 two-hybrid yeast assay. This is the first report to investigate the novel MIE of SRCs recruitment in 4-n-NP-ERα-induced estrogenicity. Overall, our results suggest that the action of 4-n-NP on estrogenic effects involves the following MIEs: the activation of ERα, the recruitment of SRC1 and SRC3, and the induction of ERE-mediated activity. The findings also provide valuable insights into the MIE associated with the different SRCs that are recruited in the adverse outcome pathways of environmental estrogens.

Simultaneous passive sampling of hydrophilic and hydrophobic emerging organic contaminants in water.

Passive sampling techniques have been considered robust tools for monitoring freely dissolved concentrations of contaminants in aquatic systems. However, few passive samplers are currently available for the simultaneous sampling of both hydrophilic and hydrophobic chemicals. In this study, we developed a novel passive sampler (a hydrophilic-lipophilic balance sorbent-embedded cellulose acetate membrane (HECAM)) for estimating the time-weighted average (TWA) concentrations of both hydrophilic and hydrophobic organic contaminants in water. In our laboratorial controlled dynamic experiments, the accumulation results of thirty-seven target chemicals (including organophosphorus flame retardants, phenols, estrogens, organophosphorus pesticides, and triazine herbicides) with a wide polarity range (1.44 < log Kow < 9.49) in the HECAM followed first-order kinetics well, and the passive sampling parameters were estimated successfully. The estimated sampling rates for the target chemicals in the HECAM ranged from 0.14 to 6.90 L d-1 in the laboratory experiment, and the log Ksw (equilibrium partition coefficient between the sampler and water) values ranged from 2.75 to 6.00. The HECAM exhibited high sampling rate for moderately hydrophilic and moderately hydrophobic chemicals. The field validation study in an urban river resulted in the detection of four target chemicals (tris(chloroisopropyl)phosphate, tris(1,3-dichloroisopropyl)phosphate, prometryn, and 4-tert-octylphenol) by the HECAM at estimated TWA concentrations of 10.9-179.5 ng L-1, which were in agreement with the measured levels found in traditional grab samples by solid-phase extraction. In summary, both the laboratory tests and field deployment showed practicable results for the HECAM passive sampling, which suggests that it is an efficient approach for simultaneous monitoring of hydrophilic and hydrophobic organic contaminants in water.

A comparison of endocrine disruption potential of nonylphenol ethoxylate, vanillin ethoxylate, 4-n-nonylphenol and vanillin in vitro.

The widely used surfactant nonylphenol ethoxylate (NPEO) and its raw material 4-n-nonylphenol (4-n-NP), as well as its degradation products, are recognized as endocrine disrupting chemicals. The USA Environmental Protection Agency (EPA) released an assessment that looked for safe alternatives to NPEO. Vanillin ethoxylate (VAEO) is a novel substitute for NPEO and is quite similar to NPEO in structure; there is a risk that it has similar endocrine disrupting effects to NPEO. However, their effects on various nuclear hormone receptors have not been thoroughly examined. In this study, the effects of NPEO, VAEO, 4-n-NP and Vanillin on the estrogen receptor α (ERα), androgen receptor (AR), thyroid hormone receptor (TR), retinoic X receptor ß (RXRß) and estrogen-related receptor γ (ERRγ) were determined and compared using a battery of recombined yeast strains expressing ß-galactosidase. The results showed that NPEO and 4-n-NP acted as significant antagonists of ER, AR, TR and ERRγ. In addition, 4-n-NP also had antagonistic activity toward RXRß. Moreover, VAEO was shown to be a very weak antagonist of TR and ERRγ, and Vanillin had no interaction with any nuclear receptors. For the first time, it was found that NPEO had AR, TR and ERRγ antagonistic effects and that 4-n-NP was an antagonist of RXRß. The in vitro data indicated that NPEO, 4-n-NP and VAEO have the potential to act as endocrine disruptors involving more than one nuclear hormone receptor, but VAEO has much lower endocrine disrupting potential than NPEO. Thus, it is critical to find safe substitutes for NPEO and a substitute of NPEO with structural analogues should be carried out with caution. Furthermore, to look for preferable alternatives for NPEO, more in vivo and in vitro studies of the alternatives concerning endocrine disruption are needed, especially in vitro studies need to involve various target points, not only focus on their effects on ER but also take other nuclear hormone receptor pathways into consideration.

Comparative toxicity study of a novel non-ionic surfactant, vanillin ethoxylates, and nonylphenol ethoxylates in Chinese hamster ovary cells in vitro.

Surfactants such as alkylphenol polyethoxylates (APEOs) and nonylphenol ethoxylates (NPEOs) are commonly used worldwide, but the majority of these compounds, together with their metabolites, have been reported to induce severe biological toxicity. Here, we evaluated for the first time the cytotoxicity, genotoxicity and mitochondrial damage in Chinese hamster ovary (CHO-K1) cells caused by a novel non-ionic surfactant, vanillin ethoxylates (VAEOs), an alternative to APEOs. In parallel, the same in vitro bioassays were conducted on NPEOs along with their metabolic byproducts 4-nonylphenol (4-NP) and vanillin. The results showed that the cytotoxic potency order was NPEOs > 4-NP > VAEOs>vanillin using CCK-8 assays. Also, 4-NP showed potential direct DNA damage in SOS/umu tests, whereas NPEOs, VAEOs and vanillin showed no positive result with and without S9 addition. In addition, none of the test compounds showed obvious genotoxic effects with low olive tail moment value using comet assays. However, all test compounds were shown to cause mitochondrial impairment by increasing mitochondrial mass and decreasing mitochondrial membrane potential in a concentration-dependent manner. And further analysis of reactive oxygen species (ROS) and mitochondrial superoxide (MNSOD) measurement showed that mitochondrial impairment was induced by oxidative stress with intracellular ROS and MNSOD overproduction. It's worth noting that VAEOs and vanillin cause relative lower cytotoxic, genotoxic and mitochondrial damage effects than NPEOs and 4-NP, indicating that VAEOs have the potential to substitute NPEOs as suitable surfactants. Take together, this study elucidates the toxicity profiles of VAEOs and NPEOs relatively comprehensively, and further toxicity analyses are suggested in the population, community and ecosystem.

Characterized in Vitro Metabolism Kinetics of Alkyl Organophosphate Esters in Fish Liver and Intestinal Microsomes.

Tris(2-butoxyethyl) phosphate (TBOEP) and tris( n-butyl) phosphate (TNBP) are the most commonly used alkyl organophosphate esters (alkyl-OPEs), and they increasingly accumulate in organisms and create potential health hazards. This study examined the metabolism of TNBP and TBOEP in Carassius carassius liver and intestinal microsomes and the production of their corresponding monohydroxylated and dealkylated metabolites. After 140 min of incubation with fish liver microsomes, the rapid depletion of TNBP and TBOEP were both best fitted to the Michaelis-Menten model (at administrated concentrations ranging from 0.5 to 200 µM), with a CLint (intrinsic clearance) of 3.1 and 3.9 µL·min-1·mg-1 protein, respectively. But no significant ( P > 0.05) biotransformation was observed for these compounds in intestinal microsomes at any administrated concentrations. In fish liver microsomes assay, bis(2-butoxyethyl) hydroxyethyl phosphate (BBOEHEP) and bis(2-butoxyethyl) 3-hydroxyl-2-butoxyethyl phosphate (3-OH-TBOEP) were the most abundant metabolites of TBOEP, and dibutyl-3-hydroxybutyl phosphate (3-OH-TNBP) was the predominant metabolite of TNBP. Similarly, the apparent Vmax values (maximum metabolic rate) of BBOEHEP and 3-OH-TNBP were also respectively highest among those of other metabolites. Further inhibition studies were conducted to identify the specific cytochrome P450 (CYP450) isozymes involved in the metabolism of TNBP and TBOEP in liver microsomes. It was confirmed that CYP3A4 and CYP1A were the significant CYP450 isoforms catalyzing the metabolism of TNBP and TBOEP in fish liver microsomes. Overall, this study emphasized the importance of hydroxylated metabolites as biomarkers for alkyl-OPEs exposure, and further research is needed to validate the in vivo formation and toxicological implications of these metabolites.

Prediction of the combined effects of multiple estrogenic chemicals on MCF-7 human breast cancer cells and a preliminary molecular exploration of the estrogenic proliferative effects and related gene expression.

The environmental risks of environmental estrogens (EEs) are often assessed via the same mode of action in the concentration addition (CA) model, neglecting the complex combined mechanisms at the genetic level. In this study, the cell proliferation effects of estrone, 17α-ethinylestradiol, 17ß-estradiol, estriol, diethylstilbestrol, estradiol valerate, bisphenol A, 4-tert-octylphenol and 4-nonylphenol were determined individually using the CCK-8 method, and the proliferation effects of a multicomponent mixture of estrogenic chemicals mixed at equipotent concentrations using a fixed-ratio design were studied using estrogen-sensitive MCF-7 cells. Furthermore, transcription factors related to cell proliferation were analyzed using RT-PCR assays to explore the potential molecular mechanisms related to the estrogenic proliferative effects. The results showed that the estrogenic chemicals act together in an additive mode, and the combined proliferative effects could be predicted more accurately by the response addition model than the CA model with regard to their adverse outcomes. Furthermore, different signaling pathways were involved depending on the different mixtures. The RT-PCR analyses showed that different estrogens have distinct avidities and preferences for different estrogen receptors at the gene level. Furthermore, the results indicated that estrogenic mixtures increased ERα, PIK3CA, GPER, and PTEN levels and reduced Akt1 level to display combined estrogenicity. These findings indicated that the potential combined environmental risks were greater than those found in some specific assessment procedures based on a similar mode of action due to the diversity of environmental pollutions and their multiple unknown modes of action. Thus, more efforts are needed for mode-of-action-driven analyses at the molecular level. Furthermore, to more accurately predict and assess the individual responses in vivo from the cellular effects in vitro, more parameters and correction factors should be taken into consideration in the addition model.

Evaluation of genotoxic effects of surface waters using a battery of bioassays indicating different mode of action.

With the burgeoning contamination of surface waters threatening human health, the genotoxic effects of surface waters have received much attention. Because mutagenic and carcinogenic compounds in water cause tumors by different mechanisms, a battery of bioassays that each indicate a different mode of action (MOA) is required to evaluate the genotoxic effects of contaminants in water samples. In this study, 15 water samples from two source water reservoirs and surrounding rivers in Shijiazhuang city of China were evaluated for genotoxic effects. Target chemical analyses of 14 genotoxic pollutants were performed according to the Environmental quality standards for surface water of China. Then, the in vitro cytokinesis-block micronucleus (CBMN) assay, based on a high-content screening technique, was used to detect the effect of chromosome damage. The SOS/umu test using strain TA1535/pSK1002 was used to detect effects on SOS repair of gene expression. Additionally, two other strains, NM2009 and NM3009, which are highly sensitive to aromatic amines and nitroarenes, respectively, were used in the SOS/umu test to avoid false negative results. In the water samples, only two of the genotoxic chemicals listed in the water standards were detected in a few samples, with concentrations that were below water quality standards. However, positive results for the CBMN assay were observed in two river samples, and positive results for the induction of umuC gene expression in TA1535/pSK1002 were observed in seven river samples. Moreover, positive results were observed for NM2009 with S9 and NM3009 without S9 in some samples that had negative results using the strain TA1535/pSK1002. Based on the results with NM2009 and NM3009, some unknown or undetected aromatic amines and nitroarenes were likely in the source water reservoirs and the surrounding rivers. Furthermore, these compounds were most likely the causative pollutants for the genotoxic effect of these water samples. Therefore, to identify causative pollutants with harmful biological effects, chemical analyses for the pollutants listed in water quality standards is not sufficient, and single-endpoint bioassays may underestimate adverse effects. Thus, a battery of bioassays based on different MOAs is required for the comprehensive detection of harmful biological effects. In conclusion, for genotoxicity screening of surface waters, the SOS/umu test system by using different strains combined with the CBMN assay was a useful approach.

Combined action of estrogen receptor agonists and antagonists in two-hybrid recombinant yeast in vitro.

Estrogen receptor (ER) antagonistic chemicals in aquatic environments are believed to influence the binding of both endogenous and exogenous estrogens to ERs in aquatic organisms. Although the combined effects of estrogenic compounds have attracted much scientific concern, little work has been done on the influence of such antiestrogens on the biological effects of estrogens. This study focused on how the presence of different amounts of antagonists affects the results of ER agonist activity tests. To achieve this, three questions were stated and answered in sequence. A two-hybrid recombinant yeast assay mediated by ER was adopted, providing a single mode of action and single target of action for this study. Mixtures created by an ER agonist and three antagonists following the fixed-ratio principle were assessed. The concentration of 17ß-estradiol causing maximum induction was set as the fixed dose of estrogen in the antagonist activity test (question 1). When the two classes of chemicals coexisted, antiestrogens, which as a whole behaved according to the concentration addition model (question 2), decreased the response of estrogen and compressed the concentration-response curves along the y-axis in the agonist activity test (question 3). This may cause the estradiol equivalent to be underestimated and potentially mask the action of estrogenic effects in toxicity evaluation of environmental samples.

Ecological risk of nonylphenol in China surface waters based on reproductive fitness.

It has been recognized that ecological risk assessment based on traditional endpoints of toxicity are unable to provide adequate protection because some chemicals may affect reproductive fitness of aquatic organisms at much lower concentrations. In this paper, predicted no effect concentrations (PNECs) for 4-nonylphenol (NP) were derived based either on endpoints of survival, development, and growth or on some nonlethal biomarkers of reproduction, biochemical and molecular biology data. The PNECs derived from reproductive lesion ranged from 0.12 to 0.60 µg NP L(-1), which was significantly lower than those derived from other endpoints. An assessment of ecological risks posed by NP to aquatic organisms in surface waters of China was conducted based on concentration levels of NP in 16 surface waters of 4 major river basins and PNECs derived from reproductive fitness by a tiered ecological risk assessment (ERA). The results showed that 14.2% and 76.5% of surface waters in China may have ecological risks resulting from reproductive fitness if the thresholds of protection for aquatic organisms were set up as 5% (HC5) and 1% (HC1), respectively. The risks were significantly greatest in the Yangtze River Basin than in other major river basins. In comparison with the risks assessed based on traditional endpoints, such as lethality, for those chemicals causing adverse effects on reproduction due to modulation of endocrine function, to be protective of ecosystem structure and function, lesser PNECs, based on sublethal effects of reproduction, were appropriate.

Determination of estrogens and estrogenic activities in water from three rivers in Tianjin, China.

Studies on estrogenic disrupting compounds (EDCs) occurrence and identification of main responsible compounds in river water discharged into the sea are of significance. In the present research, we screened estrogenic activities of 10 river water samples from 3 main rivers discharged into Bohai Sea in Tianjin using a recombinant two-hybrid yeast assay and chemical analysis by gas chromatography-mass spectrometry. All sample extracts induced significant estrogenic activity, with 17beta-estradiol equivalents (EEQ) of raw water ranging from 5.72 to 59.06 ng/L. Six most concerned EDCs in the river water samples including estrone, 17beta-estradiol, 17alpha-ethinylestradiol, estriol, diethylstilbestrol and estradiol valerate were determined, with their concentrations up to 50.70, 31.40, 24.40, 37.20, 2.56, and 8.47 ng/L, respectively. Through causality analysis by comparing the EEQ values of yeast assay and chemical analysis, 17alpha-ethinylestradiol and 17beta-estradiol were identified as the main contributors to the estrogenic effects of the river samples, accounting for the whole estrogenic activities (62.99% to 185.66%), and estrogen antagonistic compounds might presented in the heavy polluted water samples. The proposed approach using both chemical analysis and bioassay could be used for identification and evaluation of the estrogenic activity of EDCs in river water.

Immunotoxicity In Vitro Assays for Environmental Pollutants under Paradigm Shift in Toxicity Tests.

With the outbreak of COVID-19, increasingly more attention has been paid to the effects of environmental factors on the immune system of organisms, because environmental pollutants may act in synergy with viruses by affecting the immunity of organisms. The immune system is a developing defense system formed by all metazoans in the course of struggling with various internal and external factors, whose damage may lead to increased susceptibility to pathogens and diseases. Due to a greater vulnerability of the immune system, immunotoxicity has the potential to be the early event of other toxic effects, and should be incorporated into environmental risk assessment. However, compared with other toxicity endpoints, e.g., genotoxicity, endocrine toxicity, or developmental toxicity, there are many challenges for the immunotoxicity test of environmental pollutants; this is due to the lack of detailed mechanisms of action and reliable assay methods. In addition, with the strong appeal for animal-free experiments, there has been a significant shift in the toxicity test paradigm, from traditional animal experiments to high-throughput in vitro assays that rely on cell lines. Therefore, there is an urgent need to build high-though put immunotoxicity test methods to screen massive environmental pollutants. This paper reviews the common methods of immunotoxicity assays, including assays for direct immunotoxicity and skin sensitization. Direct immunotoxicity mainly refers to immunosuppression, for which the assays mostly use mixed immune cells or isolated single cells from animals with obvious problems, such as high cost, complex experimental operation, strong variability and so on. Meanwhile, there have been no stable and standard cell lines targeting immune functions developed for high-throughput tests. Compared with direct immunotoxicity, skin sensitizer screening has developed relatively mature in vitro assay methods based on an adverse outcome pathway (AOP), which points out the way forward for the paradigm shift in toxicity tests. According to the experience of skin sensitizer screening, this paper proposes that we also should seek appropriate nodes and establish more complete AOPs for immunosuppression and other immune-mediated diseases. Then, effective in vitro immunotoxicity assay methods can be developed targeting key events, simultaneously coordinating the studies of the chemical immunotoxicity mechanism, and further promoting the paradigm shift in the immunotoxicity test.

Integrated passive sampling and fugacity model to characterize fate and removal of organophosphate flame retardants in an anaerobic-anoxic-oxic municipal wastewater treatment system.

It is crucial to deeply understand the fate and removal mechanism of various organophosphate flame retardants (PFRs) in specified wastewater treatment processes. However, concentration fluctuation and matrix effect in wastewater challenge quantification of PFR flux for both field observation and model validation. We present measured seasonal distribution profiles of time-weighted average (TWA) concentrations by in situ hydrophobic and polar passive samplers and modeled mass transport and transformation by means of fugacity for 11 PFRs with varied structures in an anaerobic-anoxic-oxic (A-A-O) municipal wastewater treatment system, and provided a systematic approach to characterize fate and removal mechanism of PFRs in major compartments via various treatment processes. We find evidence that PFRs have a unique structural-dependent fate and removal in the A-A-O system. Hydrophilic chlorinated-PFRs present persistent in all major compartments and dominate in effluents with significant variations; alkyl-PFRs are majorly reduced by biodegradation; whereas hydrophobic aryl-PFRs have the highest removal percentage, contributed by both sorption on solids and biotransformation. Sensitive analysis shows the most influential operation parameters on removal efficiency varied among the PFRs with different properties. We also conclude passive sampling can be effectively applied to estimate TWA wastewater concentrations and to validate fugacity model prediction.

In vitro thyroid disrupting effects of organic extracts from WWTPs in Beijing.

It is generally known that there are many endocrine disrupting compounds (EDCs) in the effluents from wastewater treatment plants (WWTPs). Most research has focused on the occurrence of estrogenic or androgenic activities, while ignoring that there are environmental chemicals disrupting thyroid system, which is essential for growth and development in both humans and animals. In the present work, a two-hybrid yeast assay was conducted to evaluate the removal efficiencies of agonistic or antagonistic thyroid receptor (TR) mediated effects in different treatment processes of three WWTPs located in Beijing. We found no TR agonistic, but TR antagonistic activities in all processes from the WWTPs. The TR antagonistic activities in organic extracts of water samples were then calibrated regarding to a known TR-inhibitor, amiodarone hydrochloride (AH). The observed concentration of TR disrupting substances ranged from 2.35 x 10(-8) to 6.19 x 10(-7) mol/L AH in Gaobeidian WWTP, 3.76 x 10(-8) to 8.75 x 10(-8) mol/L AH in Lugouqiao WWTP, and 4.80 x 10(-9) to 2.55 x 10(-8) mol/L AH in Beixiaohe WWTP. Of the three WWTPs, the removal rates were 92.7%, 42.2%, and 23.1% respectively. Industrial sewage may contain more TR disrupting substances compared with domestic sewage. The recipient waters were found to contain considerable concentrations of TR disrupting substances that may cause adverse effects on the exposed organisms.

Estrogen-related receptor gamma disruption of source water and drinking water treatment processes extracts.

Environmental chemicals in drinking water can impact human health through nuclear receptors. Additionally, estrogen-related receptors (ERRs) are vulnerable to endocrine-disrupting effects. To date, however, ERR disruption of drinking water potency has not been reported. We used ERRgamma two-hybrid yeast assay to screen ERRgamma disrupting activities in a drinking water treatment plant (DWTP) located in north China and in source water from a reservoir, focusing on agonistic, antagonistic, and inverse agonistic activity to 4-hydroxytamoxifen (4-OHT). Water treatment processes in the DWTP consisted of pre-chlorination, coagulation, coal and sand filtration, activated carbon filtration, and secondary chlorination processes. Samples were extracted by solid phase extraction. Results showed that ERRgamma antagonistic activities were found in all sample extracts, but agonistic and inverse agonistic activity to 4-OHT was not found. When calibrated with the toxic equivalent of 4-OHT, antagonistic effluent effects ranged from 3.4 to 33.1 microg/L. In the treatment processes, secondary chlorination was effective in removing ERRgamma antagonists, but the coagulation process led to significantly increased ERRgamma antagonistic activity. The drinking water treatment processes removed 73.5% of ERRgamma antagonists. To our knowledge, the occurrence of ERRgamma disruption activities on source and drinking water in vitro had not been reported previously. It is vital, therefore, to increase our understanding of ERRy disrupting activities in drinking water.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-induced suppression of immunity in THP-1-derived macrophages and the possible mechanisms.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a well-known immunotoxic environmental pollutant. However, most immunotoxicology studies of TCDD were based on the animal models and the inner mechanisms have just focused on a few genes/proteins. In this study, the immune functions of THP-1-derived macrophages was measured with in-vitro bioassays after 24-h exposure of TCDD including environmentally relevant concentrations. RNA-seq and Weighted Gene Co-expression Network Analysis were used to characterize the immunotoxicity molecular mechanisms. Our study is the first report on the TCDD-induced effects of cell adhesion, morphology, and multiple cytokines/chemokines production on THP-1 macrophages. After TCDD treatment, we observed an inhibited cell adherence, probably attributed to the suppressed mRNA levels of adhesion molecules ICAM-1, VCAM-1 and CD11b, and a decrease in cell pseudopodia and expression of F-actin. The inflammatory cytokines TNF-α, IL-10 and other 8 cytokines/chemokines regulating granulocytes/T cells and angiogenesis were disrupted by TCDD. Alternative splicing event was found to be a sensitive target for TCDD. Using WGCNA, we identified 10 hub genes (TNF, SRC, FGF2, PTGS2, CDH2, GNG11, BDNF, WNT5A, CXCR5 and RUNX2) highly relevant to these observed phenotypes, suggesting AhR less important in the effects TCDD have on THP-1 macrophages than in other cells. Our findings broaden the understanding of TCDD immunotoxicity on macrophages and provide new potential targets for clarifying the molecular mechanisms.

In vitro estrogen-disrupting effects of organophosphate flame retardants.

Organophosphate flame retardants (OPFRs), as substitutes for polybrominated diphenyl ethers (PBDEs), are frequently detected in the environment and biota due to their widespread use. Thus, there is a need to investigate their potential estrogen-disrupting effects and possible mechanisms of action in an effort to obtain a better risk assessment. In this study, we characterized the activities on estrogen receptor α (ERα) and the estrogen-disrupting potential of fourteen OPFRs, TMP, TEP, TPP, TnBP, TiBP, THP, TPhP, TCP, DPK, MDPP, IDPP, CDP, IPPDP and MPhP, using three in vitro assays representing different specific modes of action (MoAs). In the yeast two-hybrid assay, no OPFRs induced agonistic activity, but TiBP, DPK, TPhP, MDPP, CDP and IPPDP were shown to be hydrophobicity-dependent antagonists and to compete with E2 for binding to ERα. In the MVLN cell assay, TPhP was the only OPFR among the 14 tested that was able to activate ERα-estrogen responsive element (ERE) pathways. The results from the E-SCREEN assay showed that all tested OPFRs except TMP had estrogenic properties, and G protein-coupled receptor 30 (GPR30) was involved in the estrogenicity of eight OPFRs, TiBP, THP, TPhP, TCP, MDPP, IPPDP, CDP and MPhP. It was also found that in the E-SCREEN assay, the estrogenicity of alkyl-OPFRs but not aryl-OPFRs was closely correlated to hydrophobicity. Our research suggested that most OPFRs were estrogen disruptors, but their related mechanisms were complex and might involve ERα-mediated and/or ERα-independent pathways. Further in vitro studies concerning the estrogenic effects and involved mechanisms of OPFRs, as well as comprehensive evaluations of OPFRs including health and ecological assessments are needed to determine whether they are safe substitutes for PBDEs.