E2 Degradation Research Articles

In-situ degradation of soil-sorbed 17β-estradiol using carboxymethyl cellulose stabilized manganese oxide nanoparticles: Column studies

This work tested a new remediation technology for in-situ degradation of estrogens by delivering a new class of stabilized manganese oxide (MnO2) nanoparticles in contaminated soils. The nanoparticles were prepared using a food-grade carboxymethyl cellulose (CMC) as a stabilizer, which was able to facilitate particle delivery into soil. The effectiveness of the technology was tested using 17β-estradiol (E2) as a model estrogen and three sandy loams (SL1, SL2, and SL3) as model soils. Column transport tests showed that the nanoparticles can be delivered in the three soils, though retention of the nanoparticles varied. The nanoparticle retention is strongly dependent on the injection pore velocity. The treatment effectiveness is highly dependent upon the mass transfer rates of both the nanoparticles and contaminants. When the E2-laden soils were treated with 22–130 pore volumes of a 0.174 g/L MnO2 nanoparticle suspension, up to 88% of water leachable E2 was degraded. The nanoparticles were more effective for soils that offer moderate desorption rates of E2. Decreasing injection velocity or increasing MnO2 concentration facilitate E2 degradation. The nanoparticles-based technology appears promising for in-situ oxidation of endocrine disruptors in groundwater.

Photocatalytic activity of synthesized titanate nanotubes and nanoribbons vs. commercial TiO2 under artificial solar and visible irradiation using 17β-estradiol as model micropollutant

The aim of this study was to compare photocatalytic activity of protonated titanate nanotubes (HTiNT)and nanoribbons (HTiNR) vs. TiO2 P25 under different irradiation conditions for degradation of selected water micropollutant (17β-estradiol, E2). HTiNT and HTiNR were prepared according to previously published method, hereby confirmed by means of the scanning electron microscopy (SEM)and powder X- ray diffraction (XRD). In order to check the extent of photocatalytic activity at high E2 photolysis rates due to its absorption maximum (λmax = 278 nm), reaction cell was exposed to the source of artificial solar light with enhanced UVB irradiation. HTiNT, HTiNR and commercial TiO2 were active under both visible light and solar irradiation. In each irradiation regime, the E2 degradation followed pseudo- first-order kinetics with respect to both irradiation time and energy. The rate constant decreased with the decreasing catalyst load while increased with the increasing irradiation energy for the emissions below 400 nm. On behalf of achieved nanostructural arrays the wider bandgaps were shown for HTiNT and HTiNR. Compared with TiO2 P25 almost three times lower rate constants for E2 degradation under visible irradiation were observed on behalf of band alignment effect of the P25. The photonic efficiencies (ζ0) were calculated and used for quantitative comparison of HTiNT, HTiNR and TiO2 photocatalytic activity regardless the irradiation conditions. The respective values decreased with the higher irradiation energy as related to an excess of photons available for simultaneous photolysis of E2 and its degradation intermediates.

Effects of 17β-estradiol (E2) on aqueous organisms and its treatment problem: a review.

Natural estrogens, estrone (E1), 17β-estradiol (E2) and estriol (E3) are endocrine disrupting chemicals (EDCs) that are discharged consistently and directly into surface waters with wastewater treatment plants (WWPTs) effluents, disposal sludges and in storm-water runoff. The most common and highest potential natural estrogen that causes estrogen activity in wastewater influent is E2. This review describes and attempts to summarize the main problems involved in the removal of E2 from WWTP by traditional processes, which fundamentally rely on activated sludge and provide an insufficient treatment for E2, as well as advanced oxidation processes (AOPs) that are applied in tertiary section treatment works. Biological processes affect and play an important role in the degradation of E2. However, some investigations have reported that operations that rely on high retention times have low efficiencies. Although advanced treatment technologies are available, their cost and operational considerations do not make them sustainable solutions. Therefore, E2 is still being released into aqueous areas, as shown in this study that investigates results from different countries. E2 is present on the watch list of substances in the Water Framework Directive (WFD) of the European Union since 2013 and the minimum acceptable concentration of it is 0.4 ng/L.

Degradation characteristics and metabolic pathway of 17β-estradiol (E2) by Rhodococcus sp. DS201

In this study an E2-degrading bacterium was isolated from the activated sludge of a municipal treatment plant that treats the waste from a contraceptive medicine-processing factory in Beijing, China. Using the observed morphological and physiological features of the bacterium and 16S rRNA sequence analysis, this bacterial strain was identified as Rhodococcus sp. DS201. Using single-factor experiments and orthogonal tests, it was demonstrated that, when strain DS210 bacteria were inoculated into MM medium at an initial concentration of 1 mg/L with an initial pH of 7 and an inoculum amount of 1%, complete degradation of E2 by this strain was achieved within 3 days at 30oC. After strain DS201 had degraded the E2, several E2 metabolites were detected in the culture extracts using high-performance liquid chromatography (HPLC); they were then further identified using HPLC with tandem mass spectrometry (LC-MS/MS). Mass spectrum analysis of the E2 degradation identified the following products: pent-4-enoic acid; 2-ethyl-3-hydroxy-6-methylcyclohexane-1-carboxylic acid; 3-(7a-methyl-1,5-dioxooctahydro-1H-inden-4-yl) propanoic acid; and 5-hydroxy-4-(3-hydroxypropyl)-7a-methyloctahydro-1H-inden-1-one. These products have not previously been reported as parts of a mechanism for microbial E2 degradation and were suspected to be new metabolite products. Therefore, the E2 degradation pathway by strain DS201 is proposed herein.

Isolation, Immobilization, and Degradation Performance of the 17β-Estradiol-Degrading Bacterium Rhodococcus sp. JX-2

As major endocrine disruptors, natural estrogens such as 17β-estradiol (E2) have been found with adverse effects on animals and humans. How to control E2 pollution as well as that of other estrogens in the environment is a worldwide concern. A novel E2-degrading bacterium (strain JX-2) was isolated from the activated sludge of a sewage treatment plant and was identified as Rhodococcus sp. Strain JX-2 grew well and metabolized up to 94 % of the substrate E2 added (30 mg L−1) within 7 days at 30 °C. The optimal environmental conditions for E2 degradation by JX-2 were pH 7.0 and 30 °C. Strain JX-2 was immobilized in sodium alginate. The optimal conditions for strain JX-2 immobilization were 4 % sodium alginate, 1:1 bacteria/sodium alginate ratio, 5 % CaCl2⋅2H2O, and 6 h crosslinking time. The degradation performance of immobilized strain JX-2 was apparently superior to that of the free strain, particularly under pH 8.0 either below 20 or above 35 °C. Immobilized strain JX-2 removed E2 in natural sewage and cow dung with removal efficiency of more than 64 and 81 %, respectively. This is the first report of utilizing immobilized bacteria to remove estrogens in sewage and livestock manure. The results suggest that strain JX-2 could be used to remove E2 from the environment efficiently.

Chloramines in a pilot-scale water distribution system: Transformation of 17β-estradiol and formation of disinfection byproducts

The degradation and transformation products of 17β-estradiol (E2) by chloramines in a pilot-scale water distribution system (WDS) were investigated using varying conditions including multiple mass ratios of chlorine to nitrogen (Cl/N), changing concentrations of chloramines, and different pH and pipe materials. The degradation of E2 was complete in ≤9 h in both deionized water (DW) and in the WDS under studied conditions. When the degradation rate of E2 was compared in WDS and DW, the degradation rate was appreciably greater in the WDS than in the DW at Cl/N mass ratios of 3, 4 and 6. However, at Cl/N mass ratios of 8 and 9, degradation was faster in the DW than in the WDS. The degradation rate of E2 was greatly affected by the initial total chloramine concentration, and the degradation of E2 in DW was consistent with second-order kinetics. The degradation rate of E2 in both the DW and the WDS increased with increasing pH. The order of degradation rate of E2in different pipes was: ductile iron loop (loop A) > polyethylene (PE) loop (loop B)> stainless steel loop (loop C). Ten specific degradation products of E2, produced by chloramination, were identified. Most of the degradation products of E2 chloramination were stable for more than 10 h. The degradation pathways of E2 in the WDS are proposed and briefly discussed. The concentrations of trihalomethanes (THMs), haloacetic acids (HAAs), and halogenated nitromethane (HNMs) during the degradation E2 in WDS were also determined.

Dissolved organic matter as a terminal electron acceptor in the microbial oxidation of steroid estrogen

Steroid estrogen in natural waters may be biodegraded by quinone-reducing bacteria, dissolved organic matter (DOM) may serve as a terminal electron acceptor in this process. The influence of temperature, pH, dissolved oxygen and light illumination on the reduction efficiency of anthraquinone-2-disulfonate (AQS) was investigated using 17β-estradiol (E2) as the target species. The optimum reduction conditions were found to be in the dark under anaerobic conditions at pH 8.0 and 30 °C. Quinone-reducing bacteria can use the quinone structure of DOM components as a terminal electron acceptor coupling with microbial growth to promote biodegradation. Compared with other DOM models, AQS best stimulated E2 biodegradation and the mediating effect was improved as the AQS concentration increased from 0 to 0.5 mM. However, further increase had an inhibiting effect. Natural DOM containing lake humic acid (LHA) and lake fulvic acid (LFA) had a very important accelerating effect on the degradation of E2, the action mechanism of which was consistent with that defined using DOM models. The natural DOM contained more aromatic compounds, demonstrating their greater electron-accepting capacity and generally more effective support for microorganism growth and E2 oxidation than Aldrich humic acid (HA). These results provide a more comprehensive understanding of microbial degradation of steroid estrogens in anaerobic environments and confirm DOM as an important terminal electron acceptor in pollutant transformation.

Fate of 17β-Estradiol as a model estrogen in source separated urine during integrated chemical P recovery and treatment using partial nitritation-anammox process

Recently, research on source separation followed by the treatment of urine and/or resource recovery from human urine has shown promise as an emerging management strategy. Despite contributing only 1% of the total volume of wastewater, human urine contributes about 80% of the nitrogen, 70% of the potassium, and up to 50% of the total phosphorus in wastewater. It is also a known fact that many of the micropollutants, especially selected estrogens, get into municipal wastewater through urine excretion. In this research, we investigated the fate of 17β-estradiol (E2) as a model estrogen during struvite precipitation from synthetic urine followed by the treatment of urine using a partial nitritation-anammox (PN/A) system. Single-stage and two-stage suspended growth PN/A configurations were used to remove the nitrogen in urine after struvite precipitation. The results showed an almost 95% phosphorous and 5% nitrogen recovery/removal from the synthetic urine due to struvite precipitation. The single and two stage PN/A processes were able to remove around 50% and 75% of ammonia and nitrogen present in the post struvite urine solution, respectively. After struvite precipitation, more than 95% of the E2 remained in solution and the transformation of E2 to E1 happened during urine storage. Most of the E2 removal that occurred during the PN/A process was due to sorption on the biomass and biodegradation (transformation of E2 to E1, and slow degradation of E1 to other metabolites). These results demonstrate that a combination of chemical and biological unit processes will be needed to recover and manage nutrients in source separated urine.

Problematic 15‐PGDH: The Link between 15‐PGDH and Uncontrolled Tissue Growth

15‐Hydroxyprostaglandin dehydrogenase (15‐PGDH) is the key enzyme that catalyzes the degradation of prostaglandin E2 (PGE2). The expression of 15‐PGDH is ubiquitously down‐regulated in various cancers. Whereas, overexpression of 15‐PGDH in cancer cells causes apoptosis, cell cycle arrest, and inhibition of metastasis, and hence considered as a tumor suppressor. Hypermethylation of CpG islands in the gene promoter region is an important mechanism to silence the expression of 15‐PGDH and contributes to cancer formation. 15‐PGDH physiologically antagonizes cyclooxygenase‐2 (COX‐2), an enzyme involved in inflammation and carcinogenesis. Therefore, downregulation of 15‐PGDH and overexpression of COX‐2 may coordinately increase the levels of PGE2 and exacerbate the carcinogenic process. 15‐Deoxy‐Δ 12,14 ‐prostaglandin J2, a product of the COX‐2 enzymatic pathway, upregulates the expression of 15‐PGDH in breast cancer MDA‐MD‐231 cells in a negative feedback loop. 15‐PGDH is directly regulated by the TGF‐tumor suppressor pathway. In addition to cancer research, current research involves investigating 15‐PGDH as a potential avenue for tissue regeneration. Inhibition of 15‐PGDH has been found to potentiate hematopoietic recovery in mice receiving a bone marrow. 15‐PGDH has also been found to play a central role in determination of active prostaglandin concentrations during pregnancy and may be competitively regulated by progesterone and cortisol. Mutations in the gene coding for 15‐PGDH can also cause digital clubbing, the swelling of the distal parts of the finger. Research on 15‐PGDH will unlock treatment methods for patients suffering from a wide variety of illnesses. We printed a 3D model of the 15‐PGDH protein structure to investigate the relationship between structure and function.Support or Funding InformationWalton High School SMART (Students Modeling a Research Topic) Team is sponsored by Milwaukee School of Engineering.

Effect of natural aquatic humic substances on the photodegradation of estrone.

Photodegradation of estrone (E1) was investigated under simulated solar radiation in absence and presence of the different fractions of humic substances (HS), namely humic acids (HA), fulvic acids (FA) and XAD-4 fraction. The pseudo-first order photodegradation rate constants increased from 0.1137 h(-1), in ultrapure (MQ) water, to 0.1774, 0.1943 and 0.3109 h(-1), in presence of HA, FA and XAD-4, respectively. Half-life time decreased from 6.10 h in MQ water to 3.91, 3.57 and 2.23 h in presence of HA, FA and XAD-4, respectively. These results evidence the relevant photosensitizing effect of XAD-4 fraction of HS on the degradation of E1, which, to the best of our knowledge have never been studied. Photodegradation studies were also conducted in organic matter-rich environmental aquatic matrices, namely fresh, estuarine and waste water. After 2 h, photodegradation achieved values ranged between 35.6 and 57.1% in natural water samples, compared with 26.4% in ultrapure water. The higher photodegradation occurred in an estuarine water sample, known to be rich in XAD-4 fraction and poor in HA, indicating that not only the presence of organic matter, but also its type, are determinant in the E1 photodegradation rate. Finally, the use of sodium azide as singlet oxygen ((1)O2) scavenger during the phototransformation of E1 in ultrapure and in two wastewater samples allowed to conclude that (1)O2 has an important role in the E1 photodegradation.

Electrochemical degradation of estrone using a boron-doped diamond anode in a filter-press reactor

Estrone (E1), an endocrine-disrupting chemical (EDC) with health and environmental consequences, is commonly found in wastewater worldwide; thus, effective ways to degrade this EDC are welcome. For the first time, a one-compartment filter-press reactor with a boron-doped diamond (BDD) anode is used in the electrochemical degradation of E1. The effect of the following variables on E1 degradation (monitored through LC/UV–vis) is investigated: flow rate (qV), current density (j), concentration [E1], pH, and absence or presence of Cl– ions in solution. The best degradation performance was attained under the following conditions, with total degradation of E1 (initial concentration, [E1]0=500μgL−1, in 0.1molL−1 Na2SO4; 0.5L) in about 25min: qV=2.0Lmin−1 (kapp=2.1×10−3s−1), j=10mAcm−2, and pH≤7. The addition of Cl– ions (0.36mmolL−1) to the E1 solution significantly enhances the rate of E1 degradation (independently of pH), to such an extent that only 10min were needed to attain total degradation of E1. On the other hand, in the absence of Cl– ions in solution and at j=10mAcm−2, the decay of the relative concentration of E1 ([E1]rel) does not depend on [E1]0, as would be expected for processes limited by mass transport; this means that OH radicals are present in excess. Under optimized conditions, the performance attained with the BDD anode was compared with that with a β-PbO2 anode; then, the higher oxidation power of the BDD anode became evident through its significantly better performance: a decay of [E1]rel of about 98 % was attained in just 30min, compared to only 35 % for the β-PbO2 anode after 60min of electrolysis.

Simultaneous Degradation of Estrone, 17β-Estradiol and 17α-Ethinyl Estradiol in an Aqueous UV/H2O2 System

UV/H2O2, which is an advanced treatment technology used to reduce multiple contaminants, is effective in potable water treatment. Simultaneous degradation effects and kinetics of three types of coexisting micropollutant estrogens (steroid estrogens, SEs), including estrone (E1), 17β-estradiol (E2) and 17α-ethinyl estradiol (EE2), in deionized water were studied. Experiments were carried out with ultraviolet-C (UVC) radiation, together with hydrogen peroxide (H2O2), in a cylinder photoreactor. The results demonstrated that the degradation processes of all of the estrogens strongly fit first-order kinetics. Single solutions of E1, E2 and EE2 showed higher degradation rates and removal efficiencies under the same reaction conditions compared with those under mixed conditions. Coexisting combinations of estrogens were put into the UV/H2O2 system to estimate their possible competitive influences on each other by examining their removal efficiencies and reaction rate constant, k, values. E1 is predominantly reduced rapidly during the competition, while the presence of other estrogens has negligible impacts on E1; however, the degradation of E2 and EE2 is affected by the competitive background, not in relation to the types but to the existing amounts. In the UV/H2O2 system, photocatalysis of the estrogens can stably produce an intermediate X, with the highest quantity coming from E1, while considerably lower quantities are obtained from E2 and EE2.

Synergistic degradation performance and mechanism of 17β-estradiol by dielectric barrier discharge non-thermal plasma combined with Pt–TiO2

A synergistic system of dielectric barrier discharge non-thermal plasma (DBD) combined with Pt–TiO2 was developed to investigate the degradation performance of 17β-estradiol (E2) by making full utilization of the UV light formed from the discharge zone. The Pt–TiO2 was prepared by impregnation-reduction method. The results of EDS analysis indicated that Pt was load on TiO2, the atomic percentage of Pt and amount loaded were 0.27% and 0.91at.%, respectively. The removal efficiency and degradation yields were obviously increased from 72.0% to 98.9% and 329.2×10−6 to 468.1×10−6g/kWh by addition Pt–TiO2 to DBD system as the peak voltage, E2 concentration, pH value, and photocatalyst additive amount were 12kV, 400μg/L, 5.6, and 50mg/L, respectively. Results demonstrated that the UV light formed could be utilized to strength the degradation performance of E2. The results also elucidated that the degradation process followed the first-order kinetic model, and the experimental parameters had significant effect on the first-order kinetic constants and removal efficiency of E2. Furthermore, six intermediate products were identified and their proposed structures were provided. The degradation mechanisms revealed that the active species of hydroxyl radicals and ozone had a key function in the degradation of E2 in the synergistic system.

Impaired Expression of Prostaglandin E2 (PGE2) Synthesis and Degradation Enzymes during Differentiation of Immortalized Urothelial Cells from Patients with Interstitial Cystitis/Painful Bladder Syndrome.

PurposeThe differentiated superficial cells of the urothelium restrict urine flow into the bladder wall. We have demonstrated that urothelial cells isolated from bladders of patients with interstitial cystitis/painful bladder syndrome (IC/PBS) fail to release PGE2 in response to tryptase. This study examines the expression of PGE2 synthesis and degradation enzymes in urothelial cells during differentiation.Materials and MethodsWe measured immunoprotein expression of cyclooxygenase-2 (COX-2), prostaglandin E2 synthase (PGES) and 15-hydroxyprostaglandin dehydrogenase (PGDH) in human urothelial cells and in immortalized urothelial cells isolated from the bladders of IC/PBS patients or normal subjects during stratification and differentiation produced by increased calcium and fetal bovine serum (Ca/FBS) in the culture medium for 1, 3 and 7 days.ResultsPGES immunoprotein expression increased during differentiation in normal and IC/PBS urothelial cells. COX-2 expression also increased in cells from normal patients following differentiation. Remarkably, no COX-2 expression was detectable in urothelial cells isolated from 3 out of 4 IC/PBS patients. PGDH immunoprotein expression decreased in normal cells after 1 and 3 days of Ca/FBS addition, but returned to normal after 7 days. PGDH expression was unchanged during differentiation at 1 and 3 days, but was more than 2-fold higher at 7 days compared to day 0 in the IC/PBS cells. Urothelial cells isolated from IC/PBS patients demonstrated no PGE2 release in response to tryptase under any of the experimental conditions studied.ConclusionsTaken together, our results indicate that PGE2 release is compromised during stratification and differentiation in IC/PBS urothelium and may contribute to impaired barrier function.

Removal of 17-β estradiol in water by sonolysis

Human and livestock excretions contain appreciable quantities of natural estrogens, namely, estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-estradiol (17α). E2 is the most abundant and the most potent natural estrogen, which can disrupt endocrine system even at ng/L scale. The authors investigated the feasibility of ultrasonic irradiation for E2 removal. The degradation of E2 followed pseudo first-order kinetics. The rate constant increased as the ultrasonic density increased up to 840 W/L. The removal coefficient was maintained at 0.34 ± 0.03 min−1 at initial E2 concentration from 1 to 50 μg/L. The removal reaction was independent of pH values, carbonate and humic acid in typical ranges of river water, groundwater, and effluent of wastewater treatment plant. E2 would be degraded by thermal reactions near the cavity–liquid interface. E1 and E3, endocrine-disrupting intermediates, were not detected during the ultrasonic degradation of E2. Ultrasonic degradation would be efficient for destruction of 17-β estradiol in aqueous solutions.

Activation of NF-κB by human papillomavirus 16 E1 limits E1-dependent viral replication through degradation of E1.

NF-κB is a family of transcription factors that regulate gene expression involved in many processes, such as the inflammatory response and cancer progression. Little is known about associations of NF-κB with the human papillomavirus (HPV) life cycle. We have developed a tissue culture system to conditionally induce E1-dependent replication of the human papillomavirus 16 (HPV16) genome in human cervical keratinocytes and found that expression of HPV16 E1, a viral helicase, results in reduction of IκBα and subsequent activation of NF-κB in a manner dependent on helicase activity. Exogenous expression of a degradation-resistant mutant of IκBα, which inhibits the activation of NF-κB, enhanced E1-dependent replication of the viral genome. Wortmannin, a broad inhibitor of phosphoinositide 3-kinases (PI3Ks), and, to a lesser extent, VE-822, an ATR kinase inhibitor, but not KU55933, an ATM kinase inhibitor, suppressed the activation of NF-κB and augmented E1-dependent replication of the HPV16 genome. Interestingly, the enhancement of E1-dependent replication of the viral genome was associated with increased stability of E1 in the presence of wortmannin as well as the IκBα mutant. Collectively, we propose that expression of E1 induces NF-κB activation at least in part through the ATR-dependent DNA damage response and that NF-κB in turn limits E1-dependent replication of HPV16 through degradation of E1, so that E1 and NF-κB may constitute a negative feedback loop. A major risk factor in human papillomavirus (HPV)-associated cancers is persistent infection with high-risk HPVs. To eradicate viruses from infected tissue, it is important to understand molecular mechanisms underlying the establishment and maintenance of persistent infection. In this study, we obtained evidence that human papillomavirus 16 (HPV16) E1, a viral DNA helicase essential for amplification of the viral genomes, induces NF-κB activation and that this limits E1-dependent genome replication of HPV16. These results suggest that NF-κB mediates a negative feedback loop to regulate HPV replication and that this feedback loop could be associated with control of the viral copy numbers. We could thus show for the first time that NF-κB activity is involved in the establishment and maintenance of persistent HPV infection.

Stimulation of hERG1 channel activity promotes a calcium-dependent degradation of cyclin E2, but not cyclin E1, in breast cancer cells

Cyclin E2 gene amplification, but not cyclin E1, has been recently defined as marker for poor prognosis in breast cancer, and appears to play a major role in proliferation and therapeutic resistance in several breast cancer cells. Our laboratory has previously reported that stimulation of the hERG1 potassium channel with selective activators led to down-regulation of cyclin E2 in breast cancer cells. In this work, we demonstrate that stimulation of hERG1 promotes an ubiquitin-proteasome-dependent degradation of cyclin E2 in multiple breast cancer cell lines representing Luminal A, HER2+ and Trastuzumab-resistant breast cancer cells. In addition we have also reveal that hERG1 stimulation induces an increase in intracellular calcium that is required for cyclin E2 degradation. This novel function for hERG1 activity was specific for cyclin E2, as cyclins A, B, D E1 were unaltered by the treatment. Our results reveal a novel mechanism by which hERG1 activation impacts the tumor marker cyclin E2 that is independent of cyclin E1, and suggest a potential therapeutic use for hERG1 channel activators.

Estrone degradation: does organic matter (quality), matter?

Understanding the parameters that drive E1 degradation is necessary to improve existing wastewater treatment systems and evaluate potential treatment options. Organic matter quality could be an important parameter. Microbial communities grown from activated sludge seeds using different dissolved organic matter sources were tested for E1 degradation rates. Synthetic wastewater was aged, filter-sterilized, and used as a carbon and energy source to determine if recalcitrant organic carbon enhances E1 degradation. Higher E1 degradation was observed by biomass grown on 8 d old synthetic wastewater compared to biomass grown on fresh synthetic wastewater (P = 0.033) despite much lower concentrations of bacteria. Minimal or no E1 degradation was observed in biomass grown on 2 d old synthetic wastewater. Organic carbon analyses suggest that products of cell lysis or microbial products released under starvation stress stimulate E1 degradation. Additional water sources were also tested: lake water, river water, and effluents from a municipal wastewater treatement plant and a treatment wetland. E1 degradation was only observed in biomass grown in treatment effluent. Nitrogen, dissolved organic carbon, and trace element concentrations were not causative factors for E1 degradation. In both experiments, spectrophotometric analyses reveal degradation of E1 is associated with microbially derived organic carbon but not general recalcitrance.

Fe doped TiO2–graphene nanostructures: synthesis, DFT modeling and photocatalysis

In this work, Fe-doped TiO2 nanoparticles ranging from a 0.2 to 1 weight % were grown from the surface of graphene sheet templates containing –COOH functionalities using sol–gel chemistry in a green solvent, a mixture of water/ethanol. The assemblies were characterized by a variety of analytical techniques, with the coordination mechanism examined theoretically using the density functional theory (DFT). Scanning electron microscopy and transmission electron microscopy images showed excellent decoration of the Fe-doped TiO2 nanoparticles on the surface of the graphene sheets >5 nm in diameter. The surface area and optical properties of the Fe-doped photocatalysts were measured by BET, UV and PL spectrometry and compared to non-graphene and pure TiO2 analogs, showing a plateau at 0.6% Fe. Interactions between graphene and Fe-doped anatase TiO2 were also studied theoretically using the Vienna ab initio Simulation Package based on DFT. Our first-principles theoretical investigations validated the experimental findings, showing the strength in the physical and chemical adsorption between the graphene and Fe-doped TiO2. The resulting assemblies were tested for photodegradation under visible light using 17β-estradiol (E2) as a model compound, with all investigated catalysts showing significant enhancements in photocatalytic activity in the degradation of E2.

Photocatalytic degradation of estradiol under simulated solar light and assessment of estrogenic activity

The ability of nanostructured titanium materials developed in the FP7/EU collaborative Clean Water project to photocatalytically degrade pollutants was tested, using 17β-estradiol (E2) as the model compound. The photocatalytic degradation of E2 was carried out under simulated solar light (both the UV part (280–400nm) and full spectrum (200nm–30μm)). The efficiency of the process was assessed using several indicators including the conversion yield, the mineralization yield, the formation of by-products and their endocrine disrupting effects. The newly synthesized catalysts significantly degraded E2 and their efficiency was found to depend on the irradiation wavelength range. Some of the intermediates formed during the photocatalytic treatment with ECT-1023t and Evonik P25 were identified and their estrogenic effect was evaluated in vivo using the ChgH-GFP transgenic medaka line. This analysis confirmed that in the structure of the identified by-products, the phenol group is not destroyed and that the estrogenic effect is still present in the corresponding solution. The persistence of the estrogenic effect after the photocatalytic treatment is hypothesized to be due to the presence of the phenol group in the by-products.