Review of Endocrine-Disrupting-Compound Removal Technologies in Water and Wastewater Treatment Plants: An EU Perspective

Removal of organic micropollutants in biologically active filters: A systematic quantitative review of key influencing factors

Biofiltration utilizes natural mechanisms including biodegradation and biotransformation along with other physical processes for the removal of organic micropollutants (OMPs) such as pharmaceuticals, personal care products, pesticides and industrial compounds found in (waste)water. In this systematic review, a total of 120 biofiltration studies from 25 countries were analyzed, considering various biofilter configurations, source water types, biofilter media and scales of operation. The study also provides a bibliometric analysis to identify the emerging research trends in the field. The results show that granular activated carbon (GAC) either alone or in combination with another biofiltration media can remove a broad range of OMPs efficiently. The impact of pre-oxidation on biofilter performance was investigated, revealing that pre-oxidation significantly improved OMP removal and reduced the empty bed contact time (EBCT) needed to achieve a consistently high OMP. Biofiltration with pre-oxidation had median removals ranging between 65% and >90% for various OMPs at 10-45 min EBCT with data variability drastically reducing beyond 20 min EBCT. Biofiltration without pre-oxidation had lower median removals with greater variability. The results demonstrate that pre-oxidation greatly enhances the removal of adsorptive and poorly biodegradable OMPs, while its impact on other OMPs varies. Only 19% of studies we reviewed included toxicity testing of treated effluent, and even fewer measured transformation products. Several studies have previously reported an increase in effluent toxicity because of oxidation, although it was successfully abated by subsequent biofiltration in most cases. Therefore, the efficacy of biofiltration treatment should be assessed by integrating toxicity testing into the assessment of overall removal.

Endocrine disrupting chemicals in wastewater treatment plants in Kenya, East Africa: Concentrations, removal efficiency, mass loading rates and ecological impacts

This study investigated the levels, mass loadings, removal efficiency, and associated ecotoxicological risks of selected endocrine disrupting chemicals (EDCs), namely, dibutylphthalate (DBP), diethylhexylphthalate (DEHP), dimethylphthalate (DMP), linuron (LNR) and progesterone (PGT) in wastewater, sludge, and untreated dry biosolid (UDBS) samples from twelve wastewater treatment plants (WWTPs) in nine major towns in Kenya. Analysis was done using high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS). All the wastewater influents had quantifiable levels of EDCs with DBP being the most abundant (37.49%) with a range of 4.33 ± 0.63 to 19.68 ± 1.24 μg L-1. DEHP was the most abundant in sludge and accounted for 48.2% ranging between 278.67 and 9243.49 ng g-1 dry weight (dw). In the UDBS samples, DEHP was also the most abundant (40%) of the total EDCs detected with levels ranging from 78.77 to 3938.54 ng g-1 dw. The average removal efficiency per pollutant was as follows: DMP (98.7%) > DEHP (91.7%) > PGT (83.4%) > DBP (77.9%) > LNR (72.2%) which can be attributed to sorption onto the biosolid, biological degradation, photolysis, and phytoremediation. The pH was negatively correlated to the EDC concentrations while total dissolved solids (TDS), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and electrical conductivity (EC) were positively correlated. The mass loadings were as high as 373.33 g day-1 of DBP in the treatment plants located in densely populated cities. DEHP and PGT had their Risk Quotients (RQs) > 1, posing a high risk to biota. DMP, DBP, and LNR posed medium risks as their RQ values were between 0.1 and 1. EDCs are therefore loaded to environmental compartments through either the effluent that loads these pollutants into the receiving aquatic ecosystem or through the UDBS, which are used as fertilizers in agricultural farmlands causing potential toxicological risks to aquatic and terrestrial life.

Endocrine disrupting chemicals in the environment: Environmental sources, biological effects, remediation techniques, and perspective

Endocrine disrupting chemicals (EDCs) have been identified as emerging contaminants, which poses a great threat to human health and ecosystem. Pesticides, polycyclic aromatic hydrocarbons, dioxins, brominated flame retardants, steroid hormones and alkylphenols are representative of this type of contaminant, which are closely related to daily life. Unfortunately, many wastewater treatment plants (WWTPs) do not treat EDCs as targets in the normal treatment process, resulting in EDCs entering the environment. Few studies have systematically reviewed the related content of EDCs in terms of occurrence, harm and remediation. For this reason, in this article, the sources and exposure routes of common EDCs are systematically described. The existence of EDCs in the environment is mainly related to human activities (Wastewater discharges and industrial activities). The common hazards of these EDCs are clarified based on available toxicological data. At the same time, the mechanism and effect of some mainstream EDCs remediation technologies (such as adsorption, advanced oxidation, membrane bioreactor, constructed wetland, etc.) are separately mentioned. Moreover, our perspectives are provided for further research of EDCs.

Hormetic effect of 17α-ethynylestradiol on activated sludge microbial community response

Synthetic estrogen analogues are among the most potent estrogenic contaminants in effluents from wastewater treatment plants. Although its effects have been well elucidated in the feminization of male fish and interference with the endocrine systems in humans, it has not been fully explored in the activated sludge (AS) microbiome, particularly EE2 (17α-ethynylestradiol). Therefore, in this study, the bacterial community shift in a 6-day laboratory-scale reactor in environmental (0, 5, 10, and 100 ng/L) and predictive elevated concentrations (5, 10, and 100 mg/L) of EE2 was investigated using culture-based and metagenomics approaches. Results showed significant changes (t-test, all p < 0.05) between initial and final physicochemical parameters (pH, DO, and EC). Although environmental concentrations showed a slight decrease in microbial counts (5.6 × 10⁶ to 4.6 × 10⁶ CFU/ml) after a 24-h incubation for the culturable approach, the predictive elevated concentrations (5 to 100 mg/L) revealed a drastic microbial counts reduction (5.6 × 10⁶ to 8 × 10² CFU/ml). The metagenomic data analysis uncovered that bacterial communities in the control sample were dominated by Proteobacteria, followed by Bacteroidetes and Firmicutes. The taxonomic classification after exposure of microbial communities in various concentrations revealed significant differences in community composition between environmental concentration (Shannon indices between 2.58 to 3.68) and predictive elevated concentrations (Shannon indices between 2.24 and 2.84; t-test, all p < 0.05). The EE2 enriched seven OTUs were Novosphingobium, Cloacibacterium, Stenotrophomonas, Enterobacteriaceae_unclassified, Stenotrophomonas, Enterobacteriaceae_unclassified and Rhodobacteraceae_unclassified. These results were supported by a dehydrogenase activity (DHA) test, which demonstrated less (about 40%) DHA in predictive elevated concentrations than in environmental concentrations. Notwithstanding, these findings suggest that EE2 may possess potent hormetic effect as evidenced by promotion of microbiome richness and dehydrogenase activity of AS in lower EE2 doses.

Potential of biocompatible calcium-based metal-organic frameworks for the removal of endocrine-disrupting compounds in aqueous environments

Rapid urbanization, industrialization and population growth have accelerated the amount and variety of emerging contaminants being released into the aqueous environment, including endocrine-disrupting compounds (EDCs). The introduction of these compounds constitutes a threat to human health and the environment, even at trace levels. Hence, new water treatment technologies are urgently required to effectively remove EDCs from water. The currently available technologies used in water remediation processes are expensive and ineffective, and some produce harmful by-products. Calcium-based metal-organic frameworks (Ca-MOFs) are porous synthetic materials that can potentially be applied as adsorbents. These MOFs are hydrolytically stable, biocompatible and low-cost compared with conventional porous materials. The structure of Ca-MOFs is maintained even though calcium metal centers in the structure can easily coordinate with water. Ca-MOFs and their composite derivatives have the potential for use in water purification because these biocompatible adsorbents have been shown to selectively extract a significant quantity of contaminants. This review highlights the potential of Ca-MOFs to adsorb EDCs from aqueous environments and discusses adsorbent preparation methods, adsorption mechanisms, removal capacity, water stability and recyclability. This review will support future efforts in synthesizing new biocompatible MOFs as an environmental treatment technology that can effectively remove EDCs from water, thereby improving environmental and human health.

Processing of natural fibre and method improvement for removal of endocrine-disrupting compounds

Persistent endocrine-disrupting compounds (EDCs) in bodies of water are a concern for human health and constitute an environmental issue, even if present in trace amounts. Conventional treatment systems do not entirely remove EDCs from discharge effluent. Due to the ultra-trace level of EDCs which affect human health and pose an environmental issue, developing new approaches and techniques to remove these micropollutants from the discharged effluent is vital. This review discusses the most common methods of eliminating EDCs through preliminary, primary, secondary and tertiary treatments. The adsorption process is favoured for EDC removal, as it is an economical and straightforward option. The NABC aspects, which are the need, approach, benefits and challenges, were analysed based on existing circumstances, highlighting biochar as a green and renewable adsorbent for the removal of organic contaminants. From the environmental point of view, the effectiveness of this method, which uses natural fibre from the kenaf plant as a porous and economical biochar material with a selected lignocellulosic biomass, provides insights into the advantages of biochar-derived adsorbents. Essentially, the improvement of the natural fibre as an adsorbent is a focus, using carbonisation, activation, and the physiochemical process to enhance the adsorption ability of the material for pollutants in bodies of water. This output will complement sustainable water management approaches presented in previous studies for combating the emerging pollutant crisis via novel green and environmentally safe options.

Synergistic multiple active species driven fast estrone oxidation by δ-MnO2 in the existence of methanol

Endocrine-disrupting chemicals (EDCs) cause serious threats to human health. Five types of MnO₂ were synthesized and characterized. They exhibited different removal performances for three EDCs, i.e., estrone (E1), ethynylestradiol (EE2) and bisphenol A (BPA). Only δ-MnO₂ can completely remove E1 within 120 min at pH 3.0. Free Mn (III) was determined at the beginning of the reaction and participated in the EDCs removal process. Electron spin resonance (ESR) indicated that δ-MnO₂ could produce superoxide anions (·O₂^-) and singlet oxygen (¹O₂) in the existence of methanol. The reactive oxygen species (ROS) quenching experiments showed ¹O₂ have certain contribution to the E1 removal by δ-MnO₂. The source of ROS is mainly the lattice oxygen from δ-MnO₂, and can be replenished through the layer structure destruction caused by the reaction between Mn(III) and E1. The ROS dependent EDCs removal by δ-MnO₂ leads to a deep understanding on this well-known oxidant.

Recent Advances in the Rejection of Endocrine-Disrupting Compounds from Water Using Membrane and Membrane Bioreactor Technologies: A Review

Water is a critical resource necessary for life to be sustained, and its availability should be secured, appropriated, and easily obtainable. The continual detection of endocrine-disrupting chemicals (EDCs) (ng/L or µg/L) in water and wastewater has attracted critical concerns among the regulatory authorities and general public, due to its associated public health, ecological risks, and a threat to global water quality. Presently, there is a lack of stringent discharge standards regulating the emerging multiclass contaminants to obviate its possible undesirable impacts. The conventional treatment processes have reportedly ineffectual in eliminating the persistent EDCs pollutants, necessitating the researchers to develop alternative treatment methods. Occurrences of the EDCs and the attributed effects on humans and the environment are adequately reviewed. It indicated that comprehensive information on the recent advances in the rejection of EDCs via a novel membrane and membrane bioreactor (MBR) treatment techniques are still lacking. This paper critically studies and reports on recent advances in the membrane and MBR treatment methods for removing EDCs, fouling challenges, and its mitigation strategies. The removal mechanisms and the operating factors influencing the EDCs remediation were also examined. Membranes and MBR approaches have proven successful and viable to eliminate various EDCs contaminants.

Degradation of Oxytetracycline in Aqueous Solutions: Application of Homogeneous and Heterogeneous Advanced Oxidative Processes

Oxytetracycline is one of the antibiotics most frequently used in the Shrimp Industry during the control of bacterial diseases. These emerging pollutants, which appear in low concentrations, are persistent and alternative treatments and are required for their elimination. The degradation of oxytetracycline was evaluated in an aqueous solution by applying homogeneous (UV/H2O2 and photo-Fenton) and heterogeneous (UV/TiO2/H2O2) advanced oxidative processes (AOPs). The studies were carried out using a bench reactor with short-wave ultraviolet lamps (UV-C). We quantified the extent to which the degradation of the drug had been efficient by employing highly efficient liquid chromatography (HPLC) and a PDA detector with a wavelength of 354 nm and a C18 column. The best results were obtained when applying the UV/H2O2 treatment, which attained a degradation of 97% under the initial conditions of a dose of 8 µL of H2O2 and 120 min of radiation. The pseudo-first order kinetic model proposed by Chan and Chu showed that the experimental results had an adequate fit, with values greater than R2 ≥ 0.95. Toxicity tests were applied to verify the effect of AOPs employed, when the drug was present in low concentrations. The test results demonstrated a decrease in the root growth of the species Lactuca sativa and Daucus carota.

Photodegradation of ibuprofen and four other pharmaceutical pollutants on natural pigments sensitized TiO2 nanoparticles

Pharmaceuticals and personal care products (PPCPs) in water system have drawn increasing concerns in recent years. TiO₂ -based photodegradation has shown great potential as a low-cost and sustainable technology in water treatment, however, can only use the UV light range of solar radiation which makes the system less efficient. Dyes have been studied to improve the TiO₂ system light-harvesting range, but studies on environmental friendly natural dyes are rare. In this study, a screening method using UV-Vis spectra analysis was carried out on a group of 22 different tropical natural plants for the potential applications on dye-sensitized TiO₂ in PPCP treatment. As a result, Begonia "Martin's Mystery" significantly increased TiO₂ photodegradation efficiency toward ibuprofen treatments which is first time reported in literature as our best knowledge. Moreover, the promising discovery of Begonia application in ibuprofen treatment has been successfully applied to warfarin and famotidine treatment. Similar results were expanded to many other Begonia species which indicate that Begonia extracts could be excellent sensitizers for TiO₂ -based photodegradation of PPCPs. Our discovery suggested that the screening process may potentially open a brand-new way for future TiO₂ photodegradation studies before the complex and time-consuming detailed mechanism studies. PRACTITIONER POINTS.: Natural dyes were screened as sensitizers for TiO₂ photodegradation of ibuprofen. Ibuprofen photodegradation efficiency was increased twice using Begonia "Martin's Mystery." The Begonia applications were extended to warfarin, trimethoprim, and famotidine. Promising results were also observed using five other Begonia species.

Peracetic Acid vs. Sodium Hypochlorite: Degradation and Transformation of Drugs in Wastewater

Numerous substances from different chemical sectors, from the pharmaceutical industry to the many consumer products available for everyday usage, can find their way into water intended for human consumption and wastewater, and can have adverse effects on the environment and human health. Thus, the disinfection process is an essential stage in water and wastewater treatment plants to destroy pathogenic microorganisms but it can form degradation byproducts. Sodium hypochlorite is the most common disinfectant, but the most important drawback associated with this kind of compound is the generation of toxic disinfection byproducts. Many studies have been carried out to identify alternative disinfectants, and in the last few years, peracetic acid has been highlighted as a feasible solution, particularly in wastewater treatment. This study compares the transformations of five emerging pollutants (caffeine, tramadol, irbesartan, diclofenac, trazodone) treated with peracetic acid, to evaluate their degradation and the possible formation of byproducts with those obtained with sodium hypochlorite. Although peracetic acid has many advantages, including a wide field of use against microorganisms and a low toxicity towards animal and plant organisms, it is not as effective in the degradation of the considered pollutants. These ones are recovered substantially and are unchanged quantitatively, producing a very low number of byproducts.

Removal of Organic Pollution in the Water Environment

The development of civilization entails a growing demand for consumer goods. A side effect of the production and use of these materials is the production of solid waste and wastewater. Municipal and industrial wastewater usually contain a large amount of various organic compounds and are the main source of pollution of the aquatic environment with these substances. Therefore, the search for effective methods of wastewater and other polluted water treatment is an important element of caring for the natural environment. This Special Issue contains nine peer-review articles presenting research on the determination and removal of environmentally hazardous organic compounds from aqueous samples. The presented articles were categorized into three major fields: new approaches to the degradation of water pollutants, new methods of isolation and determination of the emerging organic contaminants (EOCs), and the occurrence of EOCs in the water environment. These articles present only selected issues from a very wide area, which is the removal of organic pollution in water environment, but can serve as important references for future studies.

Effect of mixing on reductive dechlorination of persistent organic pollutants by Fe/Pd nanoparticles

Herein, we report the comparison of two different mixing methods for reductive dechlorination of gamma-hexachlorocyclohexane (γ-HCH), aldrin, and p, p'-dichlorodiphenyl-trichloroethane (p, p'-DDT), using iron/palladium (Fe/Pd) bimetallic nanoparticles. A noticeable enhancement of the reaction rate was found when the reductive dechlorination reaction was carried out in an ultrasound bath as compared with a platform shaker. These enhancements could be attributed to (a) the continuous cleaning and chemical activation of the surfaces of nanoscale Fe/Pd bimetallic nanoparticles by the combined chemical and physical effects of acoustic cavitation; and (b) the accelerated mass transport rates of target POPs to the surfaces of the Fe/Pd nanoparticles. Finally, the degradation intermediates and final products were determined by gas chromatography/mass spectrometry (GC/MS) analysis and the plausible degradation pathways for γ-HCH, aldrin, and p, p'-DDT by Fe/Pd bimetallic nanoparticles were proposed. PRACTITIONER POINTS: Exposure to POPs is a resilient global environmental and health issue. Fe/Pd bimetallic nanoparticles demonstrated > 90 % removal of POPs in the first 30 minutes of the reaction via ultrasonic mixing. GC-MS analyses provided verification of POPs degradation intermediates and final products.

Porous Waste Glass for Lead Removal in Packed Bed Columns and Reuse in Cement Conglomerates

A porous waste glass (RWPG = recycled waste porous glass) was used in wastewater treatments for the removal of lead ions from single, binary, and ternary metal solutions (with cadmium and nickel ions). Experiments were performed in columns (30 cm³, 10 g) filled with 0.5–1 mm beads till complete glass exhaustion (breakthrough). In the case of single and binary solutions, the columns were percolated at 0.2 Lh⁻¹ (2 mg Me⁺² L⁻¹); in the case of ternary solutions, the columns were percolated at 0.15–0.4 Lh⁻¹ (2 mg Me²⁺ L⁻¹) and with 2–5 mg Me²⁺ L⁻¹ influent concentration (0.2 Lh⁻¹). Lead ions were removed mainly by ion exchange and also by adsorption. From a kinetic point of view, the rate controlling step of the process was the interdiffusion of the lead ions in the Nernst stationary liquid film around the sorbent. The uptake of the metals and the glass selectivity were confirmed by Energy Dispersive X-ray spectroscopy (EDX) analysis. After lead retention process, glass beads were reused as lightweight aggregates for thermal insulating and environmental safe mortars.

Unsubstituted metallophthalocyanine catalysts for the removal of endocrine disrupting compounds using H2O2 as oxidant

Advanced oxidation processes have become increasingly important to treat non-biodegradable compounds entering environmental waters. In recent decades, water-soluble metallophthalocyanines have been shown to catalyse H₂O₂-containing oxidation reactions through the production of unique reactive species, nucleophilic metal-peroxo complexes. Few reports in the literature have examined water insoluble metallophthalocyanines (MPc). The oxidative catalytic activity of water insoluble manganese- and iron-phthalocyanine (MnPc, FePc) at pH 7 has been shown through the decolourisation of methylene blue and removal of bisphenol A. These studies expand on this previous study, exploring the catalytic activity of a range of metallophthalocyanines catalysts under both acidic and neutral conditions. FePc, while only active under neutral conditions, was the best performing catalyst. This activity was significantly improved upon by the addition of acetonitrile as a co-solvent, as well as increasing the ratio of H₂O₂ to catalyst. MnPc was catalytically active at both pH 3 and 7. FePc and MnPc catalysts showed the ability to remove bisphenol A in the presence of dam water. Reaction rates were reduced for bisphenol A removal with FePc as a catalyst but were unchanged in the presence of MnPc. The removal of 17β-estradiol, estrone, and coumestrol was successfully demonstrated, with greater than 96% removal of all tested EDC's achieved. This is the first reported study showing the removal of the phytoestrogen, coumestrol. Even though considerably lower concentrations of costly catalysts and oxidation reagents were used in our work, the removal extent of EDC's by the MPc-catalysed oxidation reactions achieved here compares favourably with literature.

Lead Ion Sorption by Perlite and Reuse of the Exhausted Material in the Construction Field

This paper deals with the possibility of using perlite as a lead ion sorbent from industrial wastewater. Dynamic (laboratory column) operations were carried-out using beads, which were percolated by metals in a 2–10 mg·L−1 concentration range. To this purpose, lead ion solutions were eluted in columns loaded with different amounts of sorbent (2–4 g) within a 1–2 mm bead size range, at 0.15–0.4 L·h−1 flow-rates. Tests were performed to complete sorbent exhaustion (column breakthrough). The highest retention was obtained at 0.3 L·h−1, with 4 g of perlite and 10 mg·L−1 of influent, lead ion concentration. Film diffusion control was the kinetic step of the process in the Nerst stationary film at the solid/liquid interface. At the end of the sorption, perlite beads were used as lightweight aggregates in the construction field (i.e., for the preparation of cement mortars). Specifically, conglomerates showing different weights and consequently different thermal insulating and mechanical properties were obtained, with potential applications in plaster or panels.

Combined Process of Ozone Oxidation and Ultrafiltration as an Effective Treatment Technology for the Removal of Endocrine-Disrupting Chemicals

Endocrine-disrupting chemicals (EDCs) in the secondary effluent discharged from wastewater treatment plants are of great concern when water reuse is intended. The combined process of ozone (O3) and ultrafiltration (UF) is a promising EDC removal method. The removal efficiency of five EDCs using O3, UF and their combination were investigated and compared. The five EDCs were estrone, 17β-estradiol, estriol, 17α-ethynyl estradiol and bisphenol A, which are typically present in secondary effluent. Results showed that organic matters in secondary effluent became easier to be removed by the combined process, with ultraviolet absorbance reduction enhanced by 11%–18% or 24%–26% compared to the UF or O3 alone. The removal efficiency of EDC concentration, estrogenicity and acute ecotoxicity by the combined process was 17%–29% or 54%–92%, 19% or 73%, 40% or 60% greater, respectively, than that of the O3 or UF alone. Particularly, when EDCs were treated by the combination of O3 and UF, about 100% EDC removal efficiency was achieved. Overall, the combined application of O3 and UF offers an effective approach to control the concentration and toxicity of EDCs in secondary effluent.

Monetary valuation of salicylic acid, methylparaben and THCOOH in a Mediterranean coastal wetland through the shadow prices methodology

The presence of pharmaceutical and personal care products and drugs of abuse (PPCPs) in wastewater treatment plants (WWTPs) indicates discharge of the effluent may not be suitable for the ecological balance of water ecosystems, such as wetlands. These PPCPs degrade water quality, considered as an ecosystem service (ES), provoking serious environmental impacts. Assessing the monetary value of PPCPs can be used as a proxy for environmental status of the ES of water quality (ESWQ). Considering PPCPs as non-desirable outputs of WWTPs, the shadow prices methodology has been implemented using directional distance function to measure the environmental avoided cost of removing salicylic acid (SA), methylparaben (MP), and THCOOH from WWTPs effluents discharged to Albufera Natural Park (Spain). The SA shows the highest shadow price (138.16 €/μg), followed by THCOOH (48.15 €/μg), and MP (30.66 €/μg). These values are interpreted as the environmental cost that would be avoided if SA, MP, and THCOOH were removed from WWTPs effluents. The non-parametric tests show that wastewater treatment technology, together with population equivalent (as a proxy of the size of urban areas) and seasonality are factors that influence shadow prices obtained. The approach used in this study highlights the use of PPCPs as status indicators of ESWQ quantified in monetary units. As a way to synthesize the essential concepts to implement the shadow prices approach, this study proposes a flow diagram to represent the relationship between all the factors involved in this work. The use of shadow prices methodology proves that removing SA, MP, and THCOOH is associated with a measurable improvement in the ESWQ of Albufera Natural Park. The findings of this study will be useful for plant managers in order to make decisions about the removal of PPCPs in WWTPs effluents.

Core–shell microspheres for the ultrafast degradation of estrogen hormone at neutral pH

In the past few years there has been growing concern about human exposure to endocrine disrupting chemicals. This kind of pollutants can bioaccumulate in aquatic organisms and lead to serious health problems, especially affecting child development. Many efforts have been devoted to achieving the efficient removal of such refractory organics. In this regard, a novel catalyst based on the combination of α-FeOOH and MnO₂@MnCO₃ catalysts has been developed by up-scalable techniques from cheap precursors and tested in the photo-Fenton-like degradation of an endocrine disruptor. Almost total degradation of 17α-ethynylestradiol hormone was achieved after only 2 min of simulated solar irradiation at neutral pH. The outstanding performance of FeOOH@MnO₂@MnCO₃ microspheres was mainly attributed to a larger generation of hydroxyl radicals, which are the primary mediators of the total oxidation for this hormone. This work contributes to the development of more cost-effective systems for the rapid and efficient removal of persistent organic pollutants present in sewage plant effluents under direct solar light.

Ultrafast photo-Fenton degradation of 17α-ethynylestradiol under simulated solar irradiation.

Emergent contaminants in the wastewater effluents of two highly populated tropical cities

Exposure to the anthropogenic chemicals known as endocrine disrupting compounds (EDCs) may result in negative biological effects. Low levels of EDCs in the environment aggravate the problem as exposure is constant. Urban areas concentrate pollution as greater volumes are released from human activities. Water for public supply is particularly vulnerable as the sewage treatment facilities may not eliminate EDCs. The goal was to assess estrogenicity and effectiveness of removal of phthalates in primary and tertiary wastewater treatment facilities in urban cities in the tropical island of Puerto Rico. A yeast bioassay used to measure estrogenicity showed higher removal with tertiary treatment. However, results in the picomolar range suggest low doses of estrogenic compounds were being released to receiving waters. For the phthalates, solid phase extraction and gas chromatography-mass spectrometry analyses revealed removals ranging from 42.9% to 92.4% with tertiary treatment. More than 90% removal was achieved for benzylbutyl phthalate, dibutyl phthalate and bis-2-ethylhexyl phthalate. However, concentrations ranging from 0.86 to 1.29 ppm for the phthalates in the outflow were detected even at the tertiary waste water treatment plant effluent implying failure of EDC removal. These results can assist managers in evaluating pollution control technologies to ameliorate the impacts of EDCs in the tropics.

Performance of a novel recycling magnetic flocculation membrane filtration process for tetracycline-polluted surface water treatment

A recycling magnetic flocculation membrane filtration (RMFMF) process integrating circulating coagulation, magnetic enhanced flocculation and membrane filtration was investigated for the treatment of surface water micro-polluted by tetracycline, a typical pharmaceutical and personal care product. A bench-scale experiment was conducted and several water quality parameters including turbidity, ultraviolet absorbance at 254 nm (UV₂₅₄), total organic carbon and tetracycline concentration were evaluated, taking coagulation membrane filtration and magnetic flocculation membrane filtration processes as reference treatments. The experimental results showed that at the optimum doses of 20 mg·L^-1 ferric chloride (FeCl₃), 4 mg·L^-1 magnetite (Fe₃O₄) and 6 mg·L^-1 reclaimed magnetic flocs in RMFMF processes, removal efficiencies of above evaluated parameters ranged from 55.8% to 92.9%, which performed best. Simultaneously, the largest average particle size of 484.71 μm and the highest fractal dimension of 1.37 of flocs were achieved, which did not only present the best coagulation effect helpful in enhancing the performance of removing multiple contaminants, but also lead to the generation of loose and porous cake layers favouring reduced permeate flux decline and membrane fouling.

The Bound Structures of 17β-Estradiol-Binding Aptamers

DNA aptamers can exhibit high affinity and selectivity towards their targets, but the aptamer-target complex structures are rarely available from crystallography and often difficult to elucidate. This is particularly true of small molecule targets, including 17β-estradiol (E2), which is becoming one of the most widely encountered endocrine-disrupting chemicals in the environment. Using molecular dynamics simulations, we demonstrate that E2 binds to a thymine loop region common to all E2-specific aptamers in the literature. Analyzing these structures allows us to design new E2 binding sequences. As well as illuminating the essential sequence and structural factors for generating specificity for E2, we demonstrate the effectiveness of molecular dynamics simulations for aptamer science.

Quantitative methylene blue decolourisation assays as rapid screening tools for assessing the efficiency of catalytic reactions

Identifying the most efficient oxidation process to achieve maximum removal of a target pollutant compound forms the subject of much research. There exists a need to develop rapid screening tools to support research in this area. In this work we report on the development of a quantitative assay as a means for identifying catalysts capable of decolourising methylene blue through the generation of oxidising species from hydrogen peroxide. Here, a previously described methylene blue test strip method was repurposed as a quantitative, aqueous-based spectrophotometric assay. From amongst a selection of metal salts and metallophthalocyanine complexes, monitoring of the decolourisation of the cationic dye methylene blue (via Fenton-like and non-Fenton oxidation reactions) by the assay identified the following to be suitable oxidation catalysts: CuSO₄ (a Fenton-like catalyst), iron(II)phthalocyanine (a non-Fenton oxidation catalyst), as well as manganese(II) phthalocyanine. The applicability of the method was examined for the removal of bisphenol A (BPA), as measured by HPLC, during parallel oxidation experiments. The order of catalytic activity was identified as FePc > MnPc > CuSO₄ for both BPA and MB. The quantitative MB decolourisation assay may offer a rapid method for screening a wide range of potential catalysts for oxidation processes.

Emerging pollutant treatments in wastewater: Cases of antibiotics and hormones

Because of the intensive use of pharmaceutical substances in human life, studies on the detection of these chemical compounds and their metabolites as pollutants in water bodies are continuously reported. Some pharmaceutical agents are associated with adverse effects to aquatic life, even at very low concentrations (ng L^-1 to μg L^-1). For instance, the presence of antibiotics and hormones has been associated with increasing proliferation of antibiotic resistant pathogens and feminization and masculinization of some aquatic organisms. Currently, new attempts are being made to minimize or fully remove these types of pollutants from aquatic systems to protect the environment and human health. In this regard, physicochemical and biological treatments are among the most promising technologies for the treatment of wastewater containing pharmaceutical pollutants. These treatments are green alternatives for the degradation of hazardous organic compounds into nontoxic by-products. Here, we review some of the physicochemical and biological treatment methods used for the removal of the most extensively used antibiotics and hormones. Enzymatic oxidation, photocatalysis and electrochemical oxidation are described in terms of the aforementioned pharmaceutically active compounds (PhACs). The use of membrane technologies to separate different groups of antibiotics and hormones prior to biologic or physicochemical treatment methods is also addressed.

Biotransformation and reduction of estrogenicity of bisphenol A by the biphenyl-degrading Cupriavidus basilensis

The biphenyl-degrading Gram-negative bacterium Cupriavidus basilensis (formerly Ralstonia sp.) SBUG 290 uses various aromatic compounds as carbon and energy sources and has a high capacity to transform bisphenol A (BPA), which is a hormonally active substance structurally related to biphenyl. Biphenyl-grown cells initially hydroxylated BPA and converted it to four additional products by using three different transformation pathways: (a) formation of multiple hydroxylated BPA, (b) ring fission, and (c) transamination followed by acetylation or dimerization. Products of the ring fission pathway were non-toxic and all five products exhibited a significantly reduced estrogenic activity compared to BPA. Cell cultivation with phenol and especially in nutrient broth (NB) resulted in a reduced biotransformation rate and lower product quantities, and NB-grown cells did not produce all five products in detectable amounts. Thus, the question arose whether enzymes of the biphenyl degradation pathway are involved in the transformation of BPA and was addressed by proteomic analyses.

Preparation of a graphene/silver hybrid membrane as a new nanofiltration membrane

In this study, we describe the preparation, characterization, water flux and rejection performance of a composite membrane formed from reduced graphene oxide (RGO) and silver nanoparticles (AgNP) via a rapid thermal reduction method.

Molecular Mechanism of Binding between 17β-Estradiol and DNA

Although 17β-estradiol (E2) is a natural molecule involved in the endocrine system, its widespread use in various applications has resulted in its accumulation in the environment and its classification as an endocrine-disrupting molecule. These molecules can interfere with the hormonal system, and have been linked to various adverse effects such as the proliferation of breast cancer. It has been proposed that E2 could contribute to breast cancer by the induction of DNA damage. Mass spectrometry has demonstrated that E2 can bind to DNA but the mechanism by which E2 interacts with DNA has yet to be elucidated. Using all-atom molecular dynamics simulations, we demonstrate that E2 intercalates (inserts between two successive DNA base pairs) in DNA at the location specific to estrogen receptor binding, known as the estrogen response element (ERE), and to other random sequences of DNA. Our results suggest that excess E2 has the potential to disrupt processes in the body which rely on binding to DNA, such as the binding of the estrogen receptor to the ERE and the activity of enzymes that bind DNA, and could lead to DNA damage.

Synthesis of high surface area carbon adsorbents prepared from pine sawdust-Onopordum acanthium L. for nonsteroidal anti-inflammatory drugs adsorption

Chemically activated carbon materials prepared from pine sawdust-Onopordum acanthium L. were studied for the removal of diclofenac and naproxen from aqueous solution. Several carbons, using different proportions of precursors were obtained (carbon C1 to carbon C5) and the chemical modification by liquid acid and basic treatments of C1 were carried out. The textural properties of the carbons, evaluated by N2 adsorption-desorption isotherms, revealed that the treatments with nitric acid and potassium hydroxide dramatically reduced the specific surface area and the pore volume of the carbon samples. The surface chemistry characterization, made by thermal programmed decomposition studies, determination of isoelectric point and Boehm's titration, showed the major presence of lactone and phenol groups on the activated carbons surface, being higher the content when the acidic strength of the carbon increased. Diclofenac and naproxen kinetic data onto C1 carbon followed pseudo-second order model. The adsorption equilibrium isotherms of C1 and the modified carbons were well described by both Sips and GAB isotherm equations. The highest adsorption capacity was found for naproxen onto C1 activated carbon, 325 mg g(-1), since the liquid acid and basic functionalization of the carbon led to a severe decreasing in the adsorption removal of the target compounds.

A review on bisphenol A occurrences, health effects and treatment process via membrane technology for drinking water

Massive utilization of bisphenol A (BPA) in the industrial production of polycarbonate plastics has led to the occurrence of this compound (at μg/L to ng/L level) in the water treatment plant. Nowadays, the presence of BPA in drinking water sources is a major concern among society because BPA is one of the endocrine disruption compounds (EDCs) that can cause hazard to human health even at extremely low concentration level. Parallel to these issues, membrane technology has emerged as the most feasible treatment process to eliminate this recalcitrant contaminant via physical separation mechanism. This paper reviews the occurrences and effects of BPA toward living organisms as well as the application of membrane technology for their removal in water treatment plant. The potential applications of using polymeric membranes for BPA removal are also discussed. Literature revealed that modifying membrane surface using blending approach is the simple yet effective method to improve membrane properties with respect to BPA removal without compromising water permeability. The regeneration process helps in maintaining the performances of membrane at desired level. The application of large-scale membrane process in treatment plant shows the feasibility of the technology for removing BPA and possible future prospect in water treatment process.