Removal Of Estrogenic Activity Research Articles

BDD-persulfate-based anodic oxidation process for progestin degradation: Optimization of conditions, eco-compatibility tests, and cost evaluation

Considering the increasing presence of the hormones levonorgestrel (LNG) and gestodene (GES) in wastewater, the limited effectiveness of conventional treatment methods, and the demand for advanced complementary processes, our study aimed to optimize an anodic oxidation treatment with a focus on low specific energy consumption (SEC) and costs. An electrochemical system coupled to a boron-doped diamond anode (BDD) was continuously used to treat synthetic and real pharmaceutical wastewater from contraceptive production. The central design composite and response surface methodology were the tools employed for optimization. The lowest SEC was obtained as a response to the main process variables: current density, initial pH, and the concentration of the support electrolyte ([Na2S2O8]). The optimal condition ([Na2S2O8]0 = 0.07 mol L−1; [LNG]0,RPW = 1.02±0.05 mg L−1 and [GES]0,RPW = 1.05±0.05 mg L−1; j = 37.5 mA cm−2; pH = 6.75) was established considering an SEC ≤ 3.6 ± 0.8 kWh g−1 and progestins removal ≥70%, which was the experimental condition used to evaluate acute toxicity to Daphnia similis and the effect on estrogenic activity removal using the YES assay. Notably, our study evaluated, for the first time, a comparative investigation that highlights the substantial effect of support electrolytes over the eco-compatibility assessment of the anodic oxidation process investigated. The adaptability of the operation indicates the prospective suitability for the implementation of the process in wastewater treatment facilities in the pharmaceutical industry.

Yeast estrogen screen assay applied in the assessment of estrogenic activity removal from dairy cattle wastewater treated by anaerobic digestion

The presence of estrogen-like endocrine disrupting chemicals (EEDC) in surface waters, soils, and groundwater has been frequently reported in the literature. Since these compounds can be excreted by humans and animals, the release of domestic sewage and animal wastewaters may be an important source of EEDC in the environment. In this context, there is a growing concern regarding the presence of these substances in the environment and their potential adverse effects on human health. However, most studies have been focused on the presence of EEDC in domestic wastewaters and the available information regarding EEDC in livestock wastewater is still limited. Therefore, this work aimed to quantify the estrogenic activity (EA) in the liquid phase of dairy cattle wastewaters and evaluate the removal of EA during anaerobic digestion, applying an adapted methodology based on the yeast estrogen screen (YES) assay, which has been widely used to analyze EA in domestic sewage. Influent and effluent dairy cattle wastewater samples from a full-scale anaerobic digester placed in an experimental farm were collected during seven months. EA concentrations in the liquid phase of raw wastewater ranged from 228 to 2182 ng.L−1 E2-eq. Anaerobic digestion was not efficient in EA removal, achieving effluent concentrations ranging from 109 to 946 ng.L−1 E2-eq. Results also indicate that the application of an estradiol-based fixed time artificial insemination protocol did not statistically contribute to the increase of EA concentrations in dairy cattle wastewater which reuse in cleaning of animal feeding operation facilities and fertigation are beneficial and economically advantageous to dairy production systems, reducing water demand in parallel to promoting organic matter and nutrient recycling. However, the potential environmental and health risks associated with the presence of EEDC in dairy cattle wastewaters should be better elucidated and evaluated.

Plasticizer phthalate esters degradation with a laccase from Trametes versicolor: effects of TEMPO used as a mediator and estrogenic activity removal.

Phthalate esters (PAEs) are toxic and persistent chemicals that are ubiquitous in the environment and have attracted worldwide attention due to their threats to the environment and human health. Dimethyl phthalate (DMP) is a relatively simple structure and one of the most observed PAEs in the environment. This study investigated the degradation of the DMP using Trametes versicolor laccase and its laccase-mediator systems. The degradation effect of laccase alone on DMP was poor, while the laccase-mediator systems can effectively enhance the degradation efficiency. Within 24h, 45% of DMP (25mg/L) was degraded in the presence of 0.8 U/mL laccase and 0.053mM 2, 2, 6, 6-tetramethylpiperidine-1-oxyl (TEMPO). A certain concentration (1mM) of metal ions Al3+, Cu2+ or Ca2+ can positively promote DMP degradation with the laccase-TEMPO system. Moreover, the structure of PAEs also had a great influence on the degradation efficiency. Higher degradation efficiencies were observed when incubating PAEs with short alkyl side chains by the laccase-TEMPO system compared to that with long alkyl side chains. Additionally, the branched-chain PAEs had a better degradation effect than the straight-chain. The estrogenic activity of the DMP solution after reaction was much smaller than that of the original solution. Finally, transformation products ortho-hydroxylated DMP and phthalic acid were identified by GC-MS and the possible degradation pathway was proposed. This study verifies the feasibility of the laccase-TEMPO system to degrade PAEs and provides a reference for exploring more potential value of laccase.

Removal of endocrine-disrupting chemical mixtures in water using chlorination and photolysis

Abstract Micropollutants have been continuously detected in freshwater. In parallel, the potential adverse effects of human exposure to endocrine-disrupting chemicals (EDCs) through drinking water have been gaining the attention of researchers and health authorities. Given this fact, this study aimed to evaluate the effectiveness of chlorination and photolysis to remove the estrogenic activity caused by mixtures of EDCs in water: estrone (E1: 100 ng L−1), 17β-estradiol (E2: 100 ng L−1), ethinylestradiol (EE2: 50 ng L−1), and nonylphenol (NP: 1,000 ng L−1) under operating conditions applicable for water treatment plants. The tests were performed using freshwater spiked with the following mixtures: E1 + E2, E1 + E2 + EE2, E1 + E2 + NP, and E1 + E2 + EE2 + NP). Removal efficiencies of up to 99.7% were achieved at a chlorine dose of 2.75 mg L–1 and 30 min of contact time. In photolysis, estrogenic activity removal was higher than 99.9% at a UV dose of 186 mJ cm–2. Results indicated that both chlorination and photolysis can be efficient to remove the estrogenic activity caused by the tested EDC mixtures in water. Furthermore, experiments suggested that EDC mixtures can be efficiently removed at feasible water disinfection operating conditions.

Assessing Performance of Wastewater Treatment Using in Vitro Cell-based Assays.

Bioanalytical tools, namely in vitro bioassays, can be employed in tandem with chemical analyses to assess the efficacy of wastewater treatment and the potential for adverse effects from the discharges of wastewater into receiving waters. In the present study, samples of untreated wastewater (i.e., influent) and treated wastewater (i.e., effluent) were collected from two wastewater treatment plants and a wastewater treatment lagoon to investigate potential differences in treatment performance. In addition, grab samples of surface water were collected downstream of the lagoon discharge to evaluate the water quality in the receiving stream. After solid-phase extraction (SPE) using ion exchange columns for basic/neutral and acidic compounds, respectively, the extracts were analyzed for a suite of 16 indicator compounds. The two SPE extracts were combined for analysis of biological responses in four in vitro cell-based bioassays. The concentrations of several indicator compounds, including the estrogens, 17β-estradiol (E2) and 17α-ethinylestradiol (EE2), were below the limits of detection. However, androstenedione and estrone were detected in several influent samples. The concentrations of these steroid hormones and some of the other indicator compounds declined during treatment, but acesulfame K, carbamazepine, trimethoprim and DEET persisted in the effluent. The MTS-CellTiter 96® AQueous One Solution Cell Proliferation Assay (MTS) indicated that cell viability was not affected by exposure to the extracts. The Qiagen Nuclear Receptors 10-Pathway Reporter Array indicated that several cellular pathways were upregulated, with the greatest upregulation observed with the estrogen receptor (i.e., induction ratios of12 to 47) and the liver X receptor (i.e., induction ratios of10 to 45). The ERα CALUX assay indicated that estrogenic activity was lower in effluents compared to influents, but the expected improved removal of estrogenic activity during nitrification was not observed. The results of the Nrf2 Luciferase Luminescence Assay indicated a lower oxidative stress in the effluent samples, except for the lagoon. Overall, the present study further demonstrates that bioassays provide complementary information to chemical analyses and offer a way to assess treatment performance, even when target contaminants are not detected. There are thus advantages to using a combination of chemical analyses and in vitro bioassays to monitor the treatment efficiency of wastewater treatment plants and to predict the potential impacts of wastewater discharges into receiving waters.

Degradation of hormones in tap water by heterogeneous solar TiO2-photocatalysis: Optimization, degradation products identification, and estrogenic activity removal

Hormones are one of the most hazardous classes of Contaminants of Emerging Concern (CEC) found in tap water, being significantly recalcitrant regarding traditional water treatment processes. In this work, the hormones estrone, 17β-estradiol, 17α-ethinylestradiol, and estriol, present in tap water, were degraded by heterogeneous solar photocatalysis in a flat-plate photochemical reactor (recycle mode) using TiO2 (P25, Evonik) as the photocatalyst. A fully automated analytical method based on online SPE and LC-UV was developed and validated for monitoring those molecules. For a fixed amount of sample (125 μL), the limit of quantification was 10 μg L−1 (for all four hormones) with coefficients of variation smaller than 20%, and accuracy between 80% and 120%, all of which are acceptable figures for this kind of determination. The reactional system was optimized with the aid of a 22 factorial design. At optimized conditions (pH ≈ 6.8, flow rate 250 mL min−1), the removal of the four hormones (250 μg L−1 each) was approximately 85% after 3 h of treatment. However, even after 9 h of treatment, it was not possible to completely remove the estrogenic activity (MCF-7 cells) of the treated tap water. The structures of some degradation products were proposed.

Accurate Removal of Trace 17β-Estradiol and Estrogenic Activity in Blended Systems under a Photoelectrocatalytic Circulating Flow.

Trace 17β-estradiol (E2) is persistent against advanced treatment when blended with higher concentrations of low-toxicity organics, thus wasting energy. A circulating-flow selective photoelectrocatalysis (CF-SPEC) system is established with a selective E2-TiO2-NR photoanode, accurately reducing 1 μg L-1 E2 to less than 0.1 ng L-1 along with eliminating estrogenic activity even when blended with natural organic matter (NOM) at a thousand times higher concentration. Such high efficiency is derived from the augmented selectivity and activity of E2-TiO2-NRs toward E2 during CF-SPEC. Under a flow, the difference in adsorption capacity between NOM and E2 is further amplified 5.6-fold. Furthermore, the higher initial •OH concentration and faster mass transfer jointly endow CF-SPEC with a stronger oxidation capacity. As a result, the removal of E2 increases by 58.7%, and the elimination of estrogenic activity increases 5.8-fold. In addition, deeper mineralization and less homo- and heterocoupling under CF-SPEC are observed, leading to more thorough estrogenic activity removal. Although additional energy is needed to maintain the flow, there is a 55% decrease in energy consumption due to the accurate removal capacity. This work suggests a combination of flow degradation and surface engineering that can be expanded for the selective removal of toxic trace pollutants in blended systems.

LED irradiated photo-Fenton for the removal of estrogenic activity and endocrine disruptors from wastewater treatment plant effluent.

The goal of this work was to evaluate the performance of the LED irradiated photo-Fenton process on the removal of (i) estrogenic activity and (ii) seven endocrine disruptors (EDs) (4-octylphenol, 4-nonylphenol, bisphenol A, estrone, 17β-estradiol, 17α-ethinylestradiol, and estriol) from real wastewater treatment plant effluent (WWTPE). EDs are a group of contaminants of emerging concern present in WWTPE and which may be recognized by hormone receptors, thus harming animal and human health. The yeast estrogenic screen test (YES) was used to quantify estrogenic activity promoted by EDs in WWTPE samples before and after photo-Fenton treatment. Tests were performed following a factorial design with different iron (20, 40, and 60mgL-1) and hydrogen peroxide (100, 200, and 300mgL-1) concentrations in a laboratory scale LED photoreactor (λ = 455nm, 1.5L, 1.6 × 10-6 Einstein s-1). EDs were analyzed by gas chromatography coupled to a mass spectrometer. Control experiments consisted of Fenton process, iron only, LED irradiation only, and H2O2 only. Optimum experimental conditions for LED photo-Fenton resulted in 62% removal of estrogenic activity and 59% mineralization. In addition, treated WWTPE was not toxic to Aliivibrio fischeri and more than 80% of EDs were removed during LED irradiated photo-Fenton. Although Fenton process showed similar efficiency to that obtained by LED photo-Fenton, a higher volume of sludge was generated in the dark. Finally, results obtained in this study confirm the applicability of LED irradiated photo-Fenton process for improving the quality of WWTPE as an alternative to solar photo-Fenton in case solar radiation is not available, thus reducing hazards associated to WWTPE reuse or discharge.

Insights into estrogenic activity removal using carbon nanotube electrochemical filter

This study reports the performance of a carbon nanotube (CNT) electrochemical filter applied to 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) degradation and their estrogenic activity removal (calculated in terms of E2 equivalent, EQ-E2). The performance of CNT electrochemical filter was assessed at different applied voltages (0–2.5 V) and aqueous matrices (ultrapure water and urban wastewater), using 37 μM of E2 and EE2, a flow rate of 1.5 mL min−1 and 10 mM of Na2SO4, used as supporting electrolyte. Surface characterization of CNT anodic filters was completed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) was used to investigate electron transfer mechanisms. The CNT electrochemical filter was successfully applied to E2 and EE2 degradation and removals higher than 95.3% (oxidative fluxes >2.94 ± 0.05 mmol h−1 m−2) were achieved when 2.5 V was applied for both ultrapure water and urban wastewater. CV results indicate that the oxidation in the CNT electrochemical filter is an irreversible process. SEM and XPS results showed evidence of the polymer formation on the CNT surface after 300 min of reaction, which probably reduced the efficiency of the process under low applied voltages. Estrogenic activity was considerably reduced and minimal EQ-E2 levels were observed when 2.5 V was applied. A residual EQ-E2 was observed, likely due to the presence of estrogens, which suggests the non-formation of estrogenic intermediates. At 2.5 V total cell potential, the energy required to remove estrogenic activity was 0.014 ± 0.001 kWh m−3 for ultrapure water and 0.021 ± 0.001 kWh m−3 for post-secondary wastewater. These results suggest a CNT electrochemical filter may have potential to effectively and efficiently remove estrogenic activity and may be a feasible process for wastewater polishing treatment.

Trace organic contaminant removal in six full-scale integrated fixed-film activated sludge (IFAS) systems treating municipal wastewater

Trace organic contaminants (TrOCs) often pass through conventional activated sludge wastewater treatment plants (CAS-WWTPs) and are discharged into surface waters, where they can threaten aquatic ecosystems and human health, largely due to the hormone disrupting effects of certain TrOCs. The integrated fixed-film activated sludge (IFAS) process is a cost-effective means of upgrading CAS-WWTPs by adding free-floating carrier media, which promotes biofilm formation in the well-mixed suspended growth reactors, providing a potential niche for slow-growing microorganisms. Although IFAS upgrades are typically aimed at enhancing nutrient removal, limited bench- and pilot-scale data indicate that TrOC removal may also be improved. However, only limited reports which focus on a small number of compounds in individual full-scale IFAS-WWTPs have been published to date, and no data is available regarding the removal of estrogenic activity in full-scale IFAS-WWTPs. In this study, six full-scale IFAS-WWTPs were surveyed to quantify TrOC and estrogenic activity removal. Twenty-four hour composite samples of secondary influent and effluent (pre-disinfection) were analyzed for total suspended solids (TSS), chemical oxygen demand (COD), ammonia, total nitrogen (TN), total phosphorus (TP), estrogenic activity, and 98 TrOCs. The biomass distribution between the suspended growth phase (i.e. mixed liquor) and IFAS media was also assessed. All IFAS-WWTPs performed well in terms of TSS, COD, and ammonia removal. TN removal varied in accordance with nitrate removal. Total solids per liter of wetted reactor volume ranged from 2.5 to 7.6 g, with 40–60% attached to media. TrOCs with no detection (17) and those with high median removal (23, ≥90% average removal) were observed. Other TrOCs had lower and more variable removal efficiencies. Qualitative comparison with CAS literature shows potentially higher IFAS removal efficiencies for a number of compounds including several which have been previously indicated in bench- or pilot-scale studies (atenolol, diclofenac, gemfibrozil, DEET, 4-nonylphenol, and 4-tert-octylphenol), as well as the chlorinated flame retardants TCIPP and TDCIPP. Effluent estrogenic activity was found to be similar to that reported for full-scale CAS-WWTPs. These results provide the first survey of multiple full-scale IFAS-WWTPs employing mobile plastic carrier media in terms of basic chemical endpoints (removal of ammonia, TN, TP, and COD), the distribution of solids within the systems, and the removal of TrOCs and estrogenic activity.

The removal of estrogenic activity with UV/chlorine technology and identification of novel estrogenic disinfection by-products

As a recently developed disinfection technology, ultraviolet (UV)/chlorine treatment has received much attention. Many studies have evaluated its effects on pathogen inactivation, contaminant removal, and formation of disinfection by-products (DBPs), but its potential for environmental estrogen removal and estrogenic DBP generation, which can also be a risk to both ecosystem and human health, have not been evaluated. In this study, UV/chlorine treatment resulted in a greater removal of estrogenic activity in synthetic effluent samples containing 17β-estradiol (E2) than did UV or chlorine treatment alone regardless of the water quality. For both the UV/chlorine and chlorine treatments, there was significant interference from NH3–N, although the UV/chlorine treatment was less affected. Estrogen receptor based affinity chromatography was used to isolate the specific estrogenic DBPs, and a novel product, with high estrogenic activity compared to E2, Δ9(11)-dehydro-estradiol, was identified. It was generated by all three treatments, and might be previously mistakenly recognized as estrone (E1). This study demonstrated that UV/chlorine is a better treatment for the removal of 17β-estradiol than chlorine and UV alone. The new identified estrogenic DBP, Δ9(11)-dehydro-estradiol, which can be isolated by affinity chromatography, could be an emerging concern in the future.

Analysis of estrogenic activity in environmental waters in Rio de Janeiro state (Brazil) using the yeast estrogen screen

The estrogenicity of waters collected from an important hydrological system in Brazil (Paraiba do Sul and Guandu Rivers) was assessed using the yeast estrogen screen (YES) assay. Sampling was performed in rivers and at the outlets of conventional water treatment plants (WTP). The removal of estrogenic activity by ozonation and chlorination after conventional water treatment (clarification and sand filtration) was investigated employing samples of the Guandu River spiked with estrogens and bisphenol A (BPA). The results revealed a preoccupying incidence of estrogenic activity at levels higher than 1ngL−1 along some points of the rivers. Another matter of concern was the number of samples from WTPs presenting estrogenicity surpassing 1ngL−1. The oxidation techniques (ozonation and chlorination) were effective for the removal of estrogenic activity and the combination of both techniques led to good results using less amounts of oxidants.

Oxidation of bisphenol A by permanganate: reaction kinetics and removal of estrogenic activity

The kinetics for reaction between bisphenol A (BPA) and permanganate was examined over pH range of 5.0-9.9 and the estrogenic activity of aqueous BPA solution after oxidation was assessed by yeast two-hybrid assay. Reaction kinetics follows the second-order rate law, with the apparent second-order rate constant of 15.1 ± 1.1 M(-1)s(-1) at pH 6.0 and 25°C and the activation energy of 48.7 kJ/mol. The kinetics exhibits pH dependency and the specific rate constants related to speciation of BPA are 50 ± 28 M(-1)s(-1), 9.6 (±0.6) × 10(3) M(-1)s(-1) and 1.4 (±0.1) × 10(4) M(-1)s(-1) for BPA, BPA(-) and BPA(2-), respectively. The results of the estrogenic/antiestrogenic activity test show that there is a hysteresis for the removal of estrogenic activity of aqueous BPA solution at pH 7.3. Removal of BPA is completed in 10 min, but complete removal of estrogenic activity requires a further 20 min.

Mechanisms of simultaneous hydrogen production and estrogenic activity removal from secondary effluent though solar photocatalysis

The mechanisms of simultaneous photocatalytic hydrogen production and estrogenic activity (EA) removal from secondary effluent were investigated by evaluating the effects of initial dissolved oxygen (DO), organic matter, and inorganic ions on the process. The photocatalytic process was enhanced and can be divided into two phases according to the availability of DO. In aerobic phase, the humic/fulvic-like compounds in hydrophilic substances fraction were preferentially decomposed by aerobic photo-formed reactive oxygen species (i.e. O2−, h+, and OH) with generation of electron donors (i.e. formaldehyde, acetaldehyde, acetate, and formate). Approximately 41% of dissolved organic carbon and 90% of EA were reduced in the aerobic phase. In the following anoxic phase, the hydrogen production was significantly improved (apparent photonic efficiency 3.04 × 10−3) by the generated electron donors and accompanied with completely EA removal by the anoxic photo-formed OH. Hydrogen production was enhanced with the presence of low concentrations of HPO42− (below 0.1 mmol/L) and HCO3− (below 0.2 mmol/L) through accelerating electrons accumulation while it was inhibited at high concentrations since the formed ion-radicals could not decompose humic/fulvic-like compounds. EA removal was inhibited by HPO42− and HCO3− through scavenging h+/$OH. The presence of NO3− (below 1 mmol/L) only resulted in minor impacts since NO3− was almost unreactive toward electronor OH in neutral conditions.

Enzymatic removal of estrogenic activity of nonylphenol and octylphenol aqueous solutions by immobilized laccase from Trametes versicolor

A fluidized bed reactor, filled with laccase-based beads, has been employed to bioremediate aqueous solutions polluted by endocrine disruptors belonging to the alkylphenols (APs) class. In particular Octylphenol and Nonylphenol have been studied. The catalytic activity of free and immobilized laccase from Trametes versicolor has been characterized as a function of pH, temperature and substrate concentration in the reaction medium. In view of practical applications for each substrate concentration the removal efficiency (RE), the time to halve the initial concentration (τ50), and the tc=0, i.e. the time to reach complete pollutant removal, have been calculated. The immobilized laccase exhibited a lower affinity for octylphenol (Km=1.11mM) than for Nonylphenol (Km=0.72mM), but all the other parameters of applicative interest resulted more significant for octylphenol. For example, the times to reach the complete removal of octylphenol compared to those for nonylphenol at the same concentration is shorter of about 15% (at low concentrations) up to 40% (at high concentrations). The study of cell proliferation with MPP89 cells, a human mesothelioma cell line, and the assay with the YES test indicated the loss of estrogenic activity of the APs solutions after laccase treatment.

Degradation of 17β-estradiol in aqueous solution by ozonation in the presence of manganese(II) and oxalic acid

Natural estrogens, such as 17β-estradiol (E2), are the main substances responsible for estrogenic activity found in domestic sewage. In the work described herein, the degradation of E2 has been investigated by single ozonation and catalytic ozonation in the presence of manganese ion (Mn2+) and oxalic acid. The presence of Mn2+ and oxalic acid in the ozonation processes significantly improved the E2 degradation and, hence, the reduction of estrogenic activity in aqueous solution. The addition of Mn2+ and oxalic acid produced many more hydroxyl radicals in the catalytic ozonation system than in the single ozonation system. Oxidation products formed during ozonation of E2 have been identified by means of gas chromatography–mass spectrometry (GC-MS), on the basis of which a possible reaction pathway for E2 degradation by ozonation is proposed. E2 was first oxidized to hydroxyl-semiquinone isomers, and these were subsequently degraded to low molecular weight compounds such as oxalic acid and malonic acid. The latter were easily oxidized by ozone to form carbon dioxide (CO2). The results demonstrate that the ozonation–Mn2+–oxalic acid system may serve as a powerful tool for removing E2, and the addition of Mn2+ and oxalic acid is favourable for the complete removal of estrogenic activity induced by steroid estrogens in aqueous solution.

Energy recovery during advanced wastewater treatment: Simultaneous estrogenic activity removal and hydrogen production through solar photocatalysis

Simultaneous estrogenic activity removal and hydrogen production from secondary effluent were successfully achieved using TiO2 microspheres modified with both platinum nanoparticles and phosphates (P–TiO2/Pt) for the first time. The coexistence of platinum and phosphate on the surface of TiO2 microspheres was confirmed by transmission electron microscope, energy-dispersive X-ray and X-ray photoelectron spectroscopy analyses. P–TiO2/Pt microspheres showed a significantly higher photocatalytic activity than TiO2 microspheres and TiO2 powders (P25) for the removal of estrogenic activity from secondary effluent with the removal ratio of 100%, 58.2% and 48.5% in 200 min, respectively. Moreover, the marked production of hydrogen (photonic efficiency: 3.23 × 10−3) was accompanied by the removal of estrogenic activity only with P–TiO2/Pt as photocatalysts. The hydrogen production rate was increasing with decreased DO concentration in secondary effluent. Results of reactive oxygen species (ROS) evaluation during P–TiO2/Pt photocatalytic process showed that O2−and OH were dominant ROS in aerobic phase, while OH was the most abundant ROS in anoxic phase. Changes of effluent organic matter (EfOM) during photocatalysis revealed that aromatic, hydrophobic, and high molecular weight fractions of EfOM were preferentially transformed into non-humic, hydrophilic, and low MW fractions (e.g. aldehydes and carboxylic acids), which were continuously utilized as electron donors in hydrogen production process.

Mechanistic Study of 17α-Ethinylestradiol Biodegradation by Pleurotus ostreatus: Tracking of Extracelullar and Intracelullar Degradation Mechanisms

The white rot fungus Pleurotus ostreatus is able to completely remove the synthetic hormone 17α-ethinylestradiol (EE2, 200 μg in 20 mL) from a liquid complex or mineral medium in 3 or 14 days, respectively. Its efficiency has also been documented in the removal of estrogenic activity that correlated with the EE2 degradation. A set of in vitro experiments using various cellular and enzyme fractions has been performed and the results showed that EE2 was degraded by isolated laccase (about 90% within 24 h). The degradation was also tested with concentrated extracellular liquid where degradation reached 50% mainly due to the laccase activity; however, after a supplementation with H₂O₂ and Mn²⁺, residual manganese-dependent peroxidase activities (40 times lower than Lac) raised the degradation to 100%. Moreover, the intracellular fraction and also laccase-like activity associated with fungal mycelium were found to be efficient in the degradation too. Isolated microsomal proteins appeared to also be involved in the process. The degradation was completely suppressed in the presence of cytochrome P-450 inhibitors, piperonylbutoxide and carbon monoxide, indicating a role of this monooxygenase in the degradation process. Attention was also paid to monitoring of changes in the estrogenic activity during these particular in vitro experiments when mainly degradations related to ligninolytic enzymes were found to decrease the estrogenic activity with EE2 removal proportionally. Several novel metabolites of EE2 were detected using different chromatographic method with mass spectrometric techniques (LC-MS, GC-MS) including also [¹³C]-labeled substrates. The results document the involvement of various different simultaneous mechanisms in the EE2 degradation by P. ostreatus by both the ligninolytic system and the eukaryotic machinery of cytochromes P-450.

Effect of water composition on TiO2 photocatalytic removal of endocrine disrupting compounds (EDCs) and estrogenic activity from secondary effluent

The effect of inorganic ions and dissolved organic matter (DOM) on the TiO2 photocatalytic removal of estrogenic activity from secondary effluents of municipal wastewater treatment plants was investigated. The presence of HPO42−, NH4+, and HCO3− resulted in a significantly negative impact on the photocatalytic removal of estrogenic activity from synthetic water due to their strong adsorption on the surface of TiO2. However, only a weak impact was noted during photocatalytic removal of estrogenic activity from secondary effluent with these ions added, since the presence of DOM in real wastewater played a more important role in inhibiting photocatalytic removal of estrogenic activity than inorganic ions. By investigating the effect of different DOM fractions on photocatalytic removal of estrogenic activity, polar compounds (PC) were found to cause a temporary increase in estrogenic activity during TiO2 photocatalysis. Fluorescence spectroscopy and molecular weight (MW) analysis on secondary effluent spiked with PC during TiO2 photocatalysis suggest that large MW organic matter (>4.5kDa) in secondary effluent, such as humic/fulvic acid, not only could play an important role in inhibiting photocatalytic removal of estrogenic activity but also is responsible for the temporary increase in estrogenic activity during the same process.

Effective Removal of Endocrine-Disrupting Compounds by Lignin Peroxidase from the White-Rot Fungus Phanerochaete sordida YK-624

The removal of endocrine-disrupting compounds (EDCs) by lignin peroxidase from white-rot fungus Phanerochaete sordida YK-624 (YK-LiP1) was investigated. Five endocrine disruptors, p-t-octylphenol (OP), bisphenol A (BPA), estrone (E(1)), 17β-estradiol (E(2)), and ethinylestradiol (EE(2)) were eliminated by YK-LiP1 more effectively than lignin peroxidase from P. chrysosporium (Pc-LiP), and OP and BPA were disappeared almost completely in the reaction mixture containing YK-LiP1 after a 24-h treatment. Particularly, the removal of estrogenic activities of E(2) and EE(2), which show much higher estrogenic activities than other EDCs such as BPA and OP, were removed following 24-h treatment with YK-LiP1. Moreover, 5,5'-bis(1,1,3,3-tetramethylbutyl)-[1,1'-biphenyl]-2,2'-diol and 5,5'-bis-[1-(4-hydroxy-phenyl)-1-methyl-ethyl]-biphenyl-2,2'-diol were identified as the main metabolite from OP or BPA, respectively. These results suggest that YK-LiP1 is highly effective in removing of EDCs by the oxidative polymerization of these compounds.