Potential for biodegradation and sorption of acetaminophen, caffeine, propranolol and acebutolol in lab-scale aqueous environments

Biodegradation of acetaminophen: Microcosm centric genomic-proteomic-metabolomics evidences

Acetaminophen (APAP) is a frequently used, over-the-counter analgesic and antipyretic medication. Considering increase in global consumption, its ubiquity in environment with potential toxic impacts has become a cause of great concern. Hence, bioremediation of this emerging contaminant is of paramount significance. The present study incorporates a microcosm centric omics approach to gain in-depth insights into APAP degradation by Paracoccus sp. APAP_BH8. It can metabolize APAP (300 mg kg-1) within 16 days in soil microcosms. Genome analysis revealed potential genes capable of mediating degradation includes M20 aminoacylase family protein, guanidine deaminase, 4-hydroxybenzoate 3-monooxygenase, and 4-hydroxyphenylpyruvate dioxygenase. Whole proteome analysis showed differential expression of enzymes and bioinformatics provided evidence for stable binding of intermediates at the active site of considered enzymes. Metabolites identified were 4-aminophenol, hydroquinone, and 3-hydroxy-cis, cis-muconate. Therefore, Paracoccus sp. APAP_BH8 with versatile enzymatic and genetic attributes can be a promising candidate for formulating improved in situ APAP bioremediation strategies.

Amended Vegetation Filters as Nature-Based Solutions for the Treatment of Pharmaceuticals: Infiltration Experiments Coupled to Reactive Transport Modelling

In small populations and scattered communities, wastewater treatment through vegetation filters (VFs), a nature-based solution, has proved to be feasible, especially for nutrient and organic matter removal. However, the presence of pharmaceuticals in wastewater and their potential to infiltrate through the vadose zone and reach groundwater is a drawback in the evaluation of VF performances. Soil amended with readily labile carbon sources, such as woodchips, enhances microbial activity and sorption processes, which could improve pharmaceutical attenuation in VFs. The present study aims to assess if woodchip amendments to a VF's soil are able to abate concentrations of selected pharmaceuticals in the infiltrating water by quantitatively describing the occurring processes through reactive transport modelling. Thus, a column experiment using soil collected from an operating VF and poplar woodchips was conducted, alongside a column containing only soil used as reference. The pharmaceuticals acetaminophen, naproxen, atenolol, caffeine, carbamazepine, ketoprofen and sulfamethoxazole were applied daily to the column inlet, mimicking a real irrigation pattern and periodically measured in the effluent. Ketoprofen was the only injected pharmaceutical that reached the column outlet of both systems within the experimental timeframe. The absence of acetaminophen, atenolol, caffeine, carbamazepine, naproxen and sulfamethoxazole in both column outlets indicates that they were attenuated even without woodchips. However, the presence of 10,11-epoxy carbamazepine and atenolol acid as transformation products (TPs) suggests that incomplete degradation also occurs and that the effect of the amendment on the infiltration of TPs is compound-specific. Modelling allowed us to generate breakthrough curves of ketoprofen in both columns and to obtain transport parameters during infiltration. Woodchip-amended columns exhibited Kd and μw values from one to two orders of magnitude higher compared to soil column. This augmentation of sorption and biodegradation processes significantly enhanced the removal of ketoprofen to over 96%.

Advances in identifying and managing emerging contaminants in aquatic ecosystems: Analytical approaches, toxicity assessment, transformation pathways, environmental fate, and remediation strategies

Emerging contaminants (ECs) are increasingly recognized as threats to human health and ecosystems. This review evaluates advanced analytical methods, particularly mass spectrometry, for detecting ECs and understanding their toxicity, transformation pathways, and environmental distribution. Our findings underscore the reliability of current techniques and the potential of upcoming methods. The adverse effects of ECs on aquatic life necessitate both in vitro and in vivo toxicity assessments. Evaluating the distribution and degradation of ECs reveals that they undergo physical, chemical, and biological transformations. Remediation strategies such as advanced oxidation, adsorption, and membrane bioreactors effectively treat EC-contaminated waters, with combinations of these techniques showing the highest efficacy. To minimize the impact of ECs, a proactive approach involving monitoring, regulations, and public education is vital. Future research should prioritize the refining of detection methods and formulation of robust policies for EC management.

Removal of hydrophilic, hydrophobic, and charged xenobiotic organic compounds from greywater using green wall media

Green walls offer a novel on-site approach for greywater treatment and reuse in densely build urban environments. However, they need to be engineered for effective removal of a wide range of emerging contaminants such as xenobiotic organic compounds (XOCs), which may be present in greywater due to extensive use of personal care products and household chemicals. This study used laboratory column design and batch experiments to investigate the performance of three lightweight green wall media (coco coir, zeolite, and perlite) and their mixture in three different combinations for the removal of twelve XOCs, covering wide range of hydrophilic, hydrophobic, and charged pollutants in greywater. The experiments were designed to assess the removal of targeted XOCs under different operational condition (i.e., hydraulic loading, infiltration rate, drying) and uncover the dominant mechanisms of their removal. Results showed excellent removal (>90%) of all XOCs in coco coir and media mix columns at the start of the experiment (i.e., fresh media and initial 2 pore volume (PV) of greywater dosing). The removal of highly hydrophobic and positively charged XOCs remained high (>90%) under all operational conditions, while hydrophilic and negatively charged XOCs exhibited significant reduction in removal after 25 PV and 50 PV, possibly due to their low adsorption affinity and electrostatic repulsion from negatively charged media. The effect of infiltration rate on the removal of XOCs was not significant; however, higher removal was achieved after 2-weeks of drying in coco coir and media mix columns. The dominant removal mechanism for most XOCs was found to be adsorption, however, a few hydrophilic XOCs (i.e., acetaminophen and atrazine) exhibited both adsorption and biodegradation removal processes. While findings showed promising prospects of unvegetated media for removing XOCs from greywater, long term studies on vegetated green wall systems are needed to understand any synergetic contribution of plants and media in removing these XOCs.

Hospitals and households as primary emission sources for risk-posing pharmaceuticals in municipal wastewater

A wide range of pharmaceutical residues is known to occur in the environment. While they are released into surface waters mainly through centralized wastewater treatment plants (WWTPs), their primary emission sources are located upstream in the sewer network. Information on emissions from different types of primary emission sources is scarce. However, such information could help direct emission reduction measures more efficiently. In this study, we analysed the concentrations of selected active pharmaceutical ingredients (APIs) in wastewater samples taken from altogether ten sites, covering primary emission sources (hospitals and households), and conventional WWTPs. The concentrations in WWTP effluents were used to identify APIs causing risk in recipient waterbodies. Furthermore, the API loads from households and hospitals were compared to those reaching the WWTP in mixed influents. Our results confirm previously published observations of several pharmaceuticals exceeding their predicted no-effect concentrations in effluent wastewaters. Moreover, the concentrations of most of the analysed APIs are comparatively high in hospital wastewaters, resulting in elevated risk quotients. While the total API loads are relatively low from primary emission sources, owing to the low wastewater volume generated at those sites, per capita emissions were shown to be several times higher at hospital sites than at household sites for APIs such as metronidazole, trimethoprim, and ofloxacin. These findings indicate, that directing emission reduction measures to hospitals could be an effective way to decrease the loads of several risk-posing APIs into the environment, especially where hospital contribution to overall wastewater flow to WWTPs is high.

Stability and WBE biomarkers possibility of 17 antiviral drugs in sewage and gravity sewers

Wastewater-based epidemiology (WBE) is a promising technique for monitoring the rapidly increasing use of antiviral drugs during the COVID-19 pandemic. It is essential to evaluate the in-sewer stability of antiviral drugs in order to determine appropriate biomarkers. This study developed an analytical method for quantification of 17 typical antiviral drugs, and investigated the stability of target compounds in sewer through 4 laboratory-scale gravity sewer reactors. Nine antiviral drugs (lamivudine, acyclovir, amantadine, favipiravir, nevirapine, oseltamivir, ganciclovir, emtricitabine and telbivudine) were observed to be stable and recommended as appropriate biomarkers for WBE. As for the other 8 unstable drugs (abacavir, arbidol, ribavirin, zidovudine, ritonavir, lopinavir, remdesivir and efavirenz), their attenuation was driven by adsorption, biodegradation and diffusion. Moreover, reaction kinetics revealed that the effects of sediments and biofilms were regarded to be independent in gravity sewers, and the rate constants of removal by biofilms was directly proportional to the ratio of surface area against wastewater volume. The study highlighted the potential importance of flow velocity for compound stability, since an increased flow velocity significantly accelerated the removal of unstable biomarkers. In addition, a framework for graded evaluation of biomarker stability was proposed to provide reference for researchers to select suitable WBE biomarkers. Compared with current classification method, this framework considered the influences of residence time and different removal mechanisms, which additionally screened four antiviral drugs as viable WBE biomarkers. This is the first study to report the stability of antiviral drugs in gravity sewers.

Primary and ultimate degradation of benzophenone-type UV filters under different environmental conditions and the underlying structure-biodegradability relationships

Ten common benzophenone-based UV filters (BPs), sharing the same basic structure and differing only in their substituents, were investigated with respect to their primary and ultimate biodegradability. This study was carried out in order to gain deeper insights into the relationship between structure and biodegradability. The primary biodegradation of the selected BPs was studied in river water at environmentally relevant concentrations (1 µg/L) while varying specific, crucial environmental conditions (aerobic, suboxic, supplementation of nutrients). For this purpose, both batch and column degradation tests were performed, which allowed a systematic study of the effects. Subsequently, the ultimate biodegradation, i.e. the potential to achieve full mineralization of BPs, was examined according to OECD guideline 301 F. The results indicate that mineralization is limited to derivatives in which both aromatic rings contain substituents. This hypothesis was supported by docking simulations showing systematic differences in the orientation of BPs within the active site of the cytochrome P450 enzyme. These differences in orientation correspond to the substitution pattern of the BPs. This study provides valuable insights for assessing the environmental hazards of this class of trace organic compounds.

Adsorption of recalcitrant contaminants of emerging concern onto activated carbon: A laboratory and pilot-scale study

According to the World Health Organization (WHO), the definition of water quality indicators, including contaminants of emerging concern (CECs), associated with the development of multi-barrier approaches for wastewater treatment, are crucial steps towards direct potable reuse of water. The aims of this study were 1) quantifying twelve CECs (including pharmaceutical, stimulant, and artificial sweetener compounds) in both untreated and treated wastewater samples in a Brazilian wastewater treatment plant (WWTP) using bidimensional liquid chromatography coupled with tandem mass spectrometry, allowing the selection of five marker (i.e., priority) CECs; 2) evaluating the adsorption potential of such selected CECs [caffeine, hydrochlorothiazide, saccharin, sucralose (SUC), and sulfamethoxazole (SMX)] onto coconut-shell granular activated carbon (GAC); and 3) investigating the removal of the same CECs by a multi-barrier system (pilot-scale, 350 L h^-1) treating the effluent of the WWTP and composed of reverse osmosis (RO), photoperoxidation (UV/H₂O₂), and filtration with GAC. Such technologies were tested separately and in binary or ternary combinations. Eleven and eight CECs were detected and quantified on the untreated and treated wastewater samples of the Brazilian WWTP, respectively. For the treated wastewater, the concentrations ranged from 499 ng L^-1 (SMX) to 87,831 ng L^-1 (SUC). The adsorption onto AC data fitted the Sips isotherm model, indicating monolayer chemisorption, which was also suggested by the mean adsorption energy values (>16 kJ mol^-1). SMX and SUC were the most and the least adsorbed CECs (4.33 and 1.21 mg g^-1, respectively). Concerning the pilot-scale treatment plant, the ternary combination (RO + UV/H₂O₂+GAC) removed >99% of the five marker CECs and promoted reductions on water color, turbidity, as well as on nitrogen and phosphorus concentrations. Further studies on water reuse could prioritize the selected marker CECs as quality indicators. While the removal of marker CECs is one of the WHO performance requirements, the RO + UV/H₂O₂+GAC system showed promising results as a first approach to direct potable reuse of water.

Assessing plant uptake of organic contaminants by food crops tomato, wheat, and corn through sap concentration factor

This study investigated uptake of two organic compounds including hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and exogenous caffeine by tomato (Solanum lycopersicum L.), corn (Zea mays L.), and wheat (Triticum aestivum L.). The plants were grown in a growth chamber under recommended conditions and then were exposed to these compounds for 19 days. The uptake of the compounds was measured by sap concentration factor. The plant samples (stem transpiration stream) and solution in the exposure media were taken and analyzed by high performance liquid chromatography-tandem mass spectrometry. The plant stem samples were analyzed after a freeze-thaw centrifugation process. The average sap concentration factor for the RDX by tomato, wheat, and corn was 0.71, 0.67, and 0.65. The average sap concentration factor for the exogenous caffeine by tomato, wheat, and corn was 0.72, 0.50, and 0.34. These relatively high sap concentration factor values were expected as available predictive models offer high sap concentration factor values for moderately hydrophobic and hydrophilic compounds. The generated sap concentration factor values for the RDX and exogenous caffeine are important for improving the accuracy of previously developed machine learning models predicting the uptake and translocation of emerging contaminants.

Adsorption of Individual and Mixtures of β-Blockers and Copper in Soils and Sediments

The (bio)availability of pharmaceuticals at solid/water interfaces is governed by their sorption, which determines their concentrations in groundwaters and surface waters in contact with biota, and can be affected by the presence of other contaminants such as metallic trace elements likely to compete for adsorption sites and form complexes with pharmaceuticals. We studied the adsorption of the pharmaceuticals propranolol and sotalol-two β-blockers-on one soil and one sediment using batch experiments to assess their (bio)availability. The influence of contact time, pH, and concentration was studied. As in the real environment these contaminants are not alone but in mixtures, and they were studied alone, simultaneously added, and in the presence of Cu²⁺ , which is known to form coordination complexes with propranolol and sotalol, but their presence in mixtures did not alter their adsorption properties. Sotalol was more mobile in water and thus more bioavailable for organisms than propranolol. The mobility in surface waters of both β-blockers and thus their bioavailabity for organisms is more important than their risk of transfer to groundwater during rainwater infiltration and to surface water due to runoff. Environ Toxicol Chem 2022;41:2700-2707. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

PPCPs and heavy metals from hydrothermal sewage sludge-derived biochar: migration in wheat and physiological response

Once the sludge was directly used in the farmland, it will have a negative impact on human health through the food chain because sludge contains pollutants. Sewage sludge pyrolysis into biochar is an effective way to realize sludge harmless and resourceful utilization. This research used hydrothermal carbonization method to convert sludge into sludge biochar (SLBC) to reduce the types and contents of pharmaceuticals and personal care products (PPCPs) and available heavy metals. Furthermore, migration of the residual caffeine (Caf), acetaminophen (Ace), and heavy metals (Cr, Pb, Cu, Zn) released from the SLBC in the wheat was assessed. The results showed that the levels of Caf, Ace, Pb, Cu, and Zn accumulated in the shoots were lower than the limit regulated by Drug and Food Additive Use Standard in China (Caf: 150 mg/kg; Ace: 2.5 ~ 5 mg/kg; Pb: 0.3 mg/kg; Cu: 10 mg/kg; Zn: 20 mg/kg). The migration of Cr from roots to shoots was also significantly controlled by SBLC. SBLC delayed the germination time of wheat seeds with increasing in hydrothermal temperature, the germination rate and root length showed a decreasing trend. Evans blue and O₂^- fluorescence staining of root tips also confirmed this conclusion. When the wheat was exposed to the low temperature and dose of SLBC, the chlorophyll contents and growth of wheat can be significantly increased; the oxidative damage of cell plasma membrane and net photosynthetic rate were reduced. However, 0.8 g/L of SLBC made plants suffer abiotic stress and caused oxidative damage to plants, and decreased membrane system stability. The study provides some parameters for sludge to realize resource utilization in the agricultural system.

The role of the sewer system in estimating urban emissions of chemicals of emerging concern

The use of chemicals by society has resulted in calls for more effective control of their emissions. Many of these chemicals are poorly characterized because of lacking data on their use, environmental fate and toxicity, as well as lacking detection techniques. These compounds are sometimes referred to as contaminants of emerging concern (CECs). Urban areas are an important source of CECs, where these are typically first collected in sewer systems and then discharged into the environment after being treated in a wastewater treatment plant. A combination of emission estimation techniques and environmental fate models can support the early identification and management of CEC-related environmental problems. However, scientific insight in the processes driving the fate of CECs in sewer systems is limited and scattered. Biotransformation, sorption and ion-trapping can decrease CEC loads, whereas enzymatic deconjugation of conjugated metabolites can increase CEC loads as metabolites are back-transformed into their parent respective compounds. These fate processes need to be considered when estimating CEC emissions. This literature review collates the fragmented knowledge and data on in-sewer fate of CECs to develop practical guidelines for water managers on how to deal with in-sewer fate of CECs and highlights future research needs. It was assessed to what extent empirical data is in-line with text-book knowledge and integrated sewer modelling approaches. Experimental half-lives (n = 277) of 96 organic CECs were collected from literature. The findings of this literature review can be used to support environmental modelling efforts and to optimize monitoring campaigns, including field studies in the context of wastewater-based epidemiology.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11157-022-09638-9.

Paracetamol degradation pathways in soil after biochar addition

Little is known about the effect of biochar on the degradation of paracetamol in soil, considering the ubiquity of this pollutant in the environment. Given the importance of the electrochemical properties of biochar for contaminant remediation, we investigated the influence of raw and designer redox-active biochars on paracetamol degradation in soil. Metabolite quantification indicated that a minimum of 53% of the spiked paracetamol was transformed in biochar-amended soil, resulting in the accumulation of different degradation products. The identification of these products allowed us to chart paracetamol degradation pathways in soil with and without biochar amendment. Some of the major degradation routes were observed to proceed via catechol and phenol, despite being previously described as having only a minor role in paracetamol metabolism. Additionally, a new transformation route from paracetamol to NAPQI was discovered in anaerobic soil originating from direct redox reactions on the surface of the designer biochars. These results may contribute to change our understanding of the environmental fate of paracetamol in soil and the role of biochar in its biodegradation.

Source, fate, transport and modelling of selected emerging contaminants in the aquatic environment: Current status and future perspectives

The occurrence of emerging contaminants (ECs), such as pharmaceuticals and personal care products (PPCPs), perfluoroalkyl and polyfluoroalkyl substances (PFASs) and endocrine-disrupting chemicals (EDCs) in aquatic environments represent a major threat to water resources due to their potential risks to the ecosystem and humans even at trace levels. Mathematical modelling can be a useful tool as a comprehensive approach to study their fate and transport in natural waters. However, modelling studies of the occurrence, fate and transport of ECs in aquatic environments have generally received far less attention than the more widespread field and laboratory studies. In this study, we reviewed the current status of modelling ECs based on selected representative ECs, including their sources, fate and various mechanisms as well as their interactions with the surrounding environments in aquatic ecosystems, and explore future development and perspectives in this area. Most importantly, the principles, mathematical derivations, ongoing development and applications of various ECs models in different geographical regions are critically reviewed and discussed. The recommendations for improving data quality, monitoring planning, model development and applications were also suggested. The outcomes of this review can lay down a future framework in developing a comprehensive ECs modelling approach to help researchers and policymakers effectively manage water resources impacted by rising levels of ECs.

Photodegradation of acebutolol in natural waters: Important roles of carbonate radical and hydroxyl radical

Acebutolol (ACE) has been widely used for the treatment of cardiovascular disorders, and its photochemical fate in natural waters is a matter of concern due to its ubiquitous occurrence and its toxicity to aquatic organisms. In this study, the photodegradation of ACE in river water and synthetic waters were investigated under simulated sunlight irradiation. The results demonstrated that ACE photodegradation rate in river water was 3.2 times higher than that in pure water. Then the influences of HCO₃^-, NO₃^- and DOM on ACE photolysis were investigated under their concentrations similar with the ones in river water. ACE photodegradation was significantly enhanced in the presence of HCO₃^- alone, and the scavenging experiments and the electron paramagnetic resonance experiments together proved that HCO₃^- could be oxidized by triplet-excited state of ACE to generate CO₃^•-, which subsequently played a key role in ACE degradation. The presence of both NO₃^- and DOM also increased the ACE photodegradation rates, and •OH and ³DOM* were found to be involved in the degradation. In addition, when DOM was added to a solution with HCO₃^-, the enhancement effect of HCO₃^- on ACE photodegradation was weakened due to the scavenging of CO₃^•- by DOM combined with the light screening effect of DOM.

Impact of Artificial Infiltration on the Removal of Nonsteroidal Anti-Inflammatory Drugs during Treatment of Surface Water

The content of pharmaceuticals in natural waters is steadily increasing. Especially nonsteroidal anti-inflammatory drugs (NSAIDs) are often detected in natural waters due to their widespread use. This group of compounds includes commonly used representatives, such as paracetamol and ketoprofen. The quality of natural waters determines the processes applied for the treatment of drinking water. The methods used in order to remove pharmaceuticals from treated water include adsorption and biologically active filtration. Both processes also occur during artificial infiltration (forced flow of intake surface water through the ground to the collecting wells) at surface water intakes. The processes, which occur in the soil, change the water quality characteristics to a great extent. The goal of the study was to evaluate the removal efficiency of paracetamol and ketoprofen in the process of artificial infiltration used as a pre-treatment of surface water. The studies were conducted at a field experimental installation located at the technical artificial infiltration intake. The experimental installation consisted of three metering wells (piezometers) which were located on the way between the bank of the infiltration pond and the collecting well. The collected water samples allowed to evaluate the change of selected NSAIDs concentrations during the passage of water through the ground. The analysis procedure included solid phase extraction (SPE) and high-performance liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). Removal of the studied NSAIDs in the infiltration process occurred with variable effectiveness throughout the year. Paracetamol was removed with annual efficiency equal to 42%, although no significant removal of ketoprofen was observed.

Neuromotor activity inhibition in zebrafish early-life stages after exposure to environmental relevant concentrations of caffeine

Caffeine (CAF), a neuroactive compound, has been found in surface waters at concentrations ranging from few nanograms up to micrograms and may induce adverse effects in aquatic vertebrates. Thus, the aim of this study was to evaluate the potential of CAF in affecting fish early-life stages in a wide concentration range, including occurring levels in surface waters. Specimens of zebrafish in early-life stages were exposed to CAF for 168 h and survival, developmental alterations, locomotor activity and acetylcholinesterase activity were evaluated. CAF induced mortality in embryos unable to hatch or in larvae after hatching (LC₅₀ - 168 h = 283.2 mg/L). Tail deformities were observed in organisms exposed to concentrations ≥ 40 mg/L, while edemas were found at concentrations of 100 mg/L. CAF also decreased the total swimming time and distance moved of exposed organisms (LOEC = 0.0006 mg/L). Locomotor inhibition may be associated with an acetylcholinesterase inhibition observed at concentration ≥ 0.0088 mg/L. Therefore, the hazard of CAF for fish populations deserves further attention since unexpected effects on neuro-behavioral parameters occurs at concentrations often detected in natural aquatic ecosystems.

Pharmaceutical Compounds in Aquatic Environments-Occurrence, Fate and Bioremediation Prospective

Various contaminants of emerging concern (CECs) have been detected in different ecosystems, posing a threat to living organisms and the environment. Pharmaceuticals are among the many CECs that enter the environment through different pathways, with wastewater treatment plants being the main input of these pollutants. Several technologies for the removal of these pollutants have been developed through the years, but there is still a lack of sustainable technologies suitable for being applied in natural environments. In this regard, solutions based on natural biological processes are attractive for the recovery of contaminated environments. Bioremediation is one of these natural-based solutions and takes advantage of the capacity of microorganisms to degrade different organic pollutants. Degradation of pollutants by native microorganisms is already known to be an important detoxification mechanism that is involved in natural attenuation processes that occur in the environment. Thus, bioremediation technologies based on the selection of natural degrading bacteria seem to be a promising clean-up technology suitable for application in natural environments. In this review, an overview of the occurrence and fate of pharmaceuticals is carried out, in which bioremediation tools are explored for the removal of these pollutants from impacted environments.

Biodegradation of salicylic acid, acetaminophen and ibuprofen by bacteria collected from a full-scale drinking water biofilter

This study examined the biodegradation of two pharmaceuticals-acetaminophen, and ibuprofen, and one natural organic surrogate-salicylic acid, by bacteria seeded from backwash water collected from a full-scale biofiltration plant. The degradation was studied in the presence of oxygen. Complete removal of salicylic acid was observed in 27-66 h depending on the seasonality of the collected backwash water, while 90-92% acetaminophen removal was observed in more than 225 h. Ibuprofen demonstrated poor removal efficiencies with only 50% biodegradation after 230 h. Adenosine tri phosphate (ATP) in the reactor was found to be linked with the biodegradation rate. ATP was found to be correlated with oxygen uptake rate (OUR). ATP also had a correlation with each of extracellular polymeric substances (EPS), protein and polysaccharides. These results highlight the potential for increasing the biodegradation rates to achieve enhanced contaminant removal.

Tandem field and laboratory approaches to quantify attenuation mechanisms of pharmaceutical and pharmaceutical transformation products in a wastewater effluent-dominated stream

Evolving complex mixtures of pharmaceuticals and transformation products in effluent-dominated streams pose potential impacts to aquatic species; thus, understanding the attenuation dynamics in the field and characterizing the prominent attenuation mechanisms of pharmaceuticals and their transformation products (TPs) is critical for hazard assessments. Herein, we determined the attenuation dynamics and the associated prominent mechanisms of pharmaceuticals and their corresponding TPs via a combined long-term field study and controlled laboratory experiments. For the field study, we quantified spatiotemporal exposure concentrations of five pharmaceuticals and six associated TPs in a small, temperate-region effluent-dominated stream during baseflow conditions where the wastewater plant was the main source of pharmaceuticals. We selected four sites (upstream, at, and two progressively downstream from effluent discharge) and collected water samples at 16 time points (64 samples in total, approximately twice monthly, depending on flows) for 1 year. Concurrently, we conducted photolysis, sorption, and biodegradation batch tests under controlled conditions to determine the major attenuation mechanisms. We observed 10-fold greater attenuation rates in the field compared to batch tests, demonstrating that connecting laboratory batch tests with field measurements to enhance predictive power is a critical need. Batch systems alone, often used for assessment, are useful for determining fate processes but poorly approximate in-stream attenuation kinetics. Sorption was the dominant attenuation process (t_1/2<7.7 d) for 5 of 11 compounds in the batch tests, while the other compounds (n = 6) persisted in the batch tests and along the 5.1 km stream reach. In-stream parent-to-product transformation was minimal. Differential attenuation contributed to the evolving pharmaceutical mixture and created changing exposure conditions with concomitant implications for aquatic and terrestrial biota. Tandem field and laboratory characterization can better inform modeling efforts for transport and risk assessments.

Increasing accuracy of field-scale studies to investigate plant uptake and soil dissipation of pharmaceuticals

Pharmaceuticals and personal care products (PPCPs) can enter agricultural fields through wastewater irrigation, biosolid amendments, or urine fertilization. Numerous studies have assessed the risk of PPCP contamination, however there are no standardized methodologies for sample treatment, making the interpretation of results challenging. Various time periods between sampling and analysis have been reported (shipping, storage, etc.), but literature is lacking in the evaluation of PPCP degradation amidst this process. This study assessed the stability of 20 pharmaceuticals (200 μg L^-1) in soil and crops stored at -40 °C for 7, 30, and 310 days. After 310 days, caffeine, meprobamate, trimethoprim, primidone, carbamazepine, anhydro-erythromycin and dilantin were found to be stable (≥75% recovery) in all matrices. On the other hand, acetaminophen, amitriptyline, bupropion, lamotrigine, sulfamethoxazole, naproxen, ibuprofen, and paroxetine were unstable after 30 days in at least one of the matrices investigated. Due to variations in analyte stability, fortification with isotopically-labelled surrogates at the point of sample collection was evaluated in comparison to fortification after shipment and storage, immediately prior to extraction. Chromatographic peak areas of stable analytes were found to be reproducible (±15%) in field-fortified samples, indicating that no additional error occurred during sample handling under field conditions despite having a less controlled environment. Unstable analytes revealed notable differences in peak areas between fortification times, suggesting that fortification immediately after sample collection is crucial to account for analyte losses during shipping and storage, resulting in accurate quantification of PPCPs.

A Review of Caffeine Adsorption Studies onto Various Types of Adsorbents

A systematic literature review of publications from 2000 to 2020 was carried out to identify research trends on adsorbent materials for the removal of caffeine from aqueous solutions. Publications were retrieved from three databases (Scopus, Web of Science, and Google Scholar). Words "adsorption AND caffeine" were examined into titles, abstracts, and keywords. A brief bibliometric analysis was performed with emphasis on the type of publication and of most cited articles. Materials for the removal of caffeine were classified according to the type of material into three main groups: organic, inorganic, and composites, each of them subdivided into different subgroups consistent with their origin or production. Tables resume for each subgroup of adsorbents the key information: specific surface area, dose, pH, maximum adsorption capacity, and isotherm models for the removal of caffeine. The highest adsorption capacities were achieved by organic adsorbents, specifically those with granular activated carbon (1961.3 mg/g) and grape stalk activated carbon (916.7 mg/g). Phenyl-phosphate-based porous organic polymer (301 mg/g), natural sandy loam sediment (221.2 mg/g), composites of MCM-48 encapsulated graphene oxide (153.8 mg/g), and organically modified clay (143.7 mg/g) showed adsorption capacities lower than those of activated carbons. In some activated carbons, a relation between the specific surface area (SSA) and the maximum adsorption capacity (Q max) was found.

Caffeine removal from aqueous media by adsorption: An overview of adsorbents evolution and the kinetic, equilibrium and thermodynamic studies

Caffeine is an emerging pollutant and is considered the most representative pollutant of the Pharmaceutical Active due to its high consumption by the general population. It can be used to track pollution caused by humans. Different technologies have been employed to remove the caffeine from aqueous media, however the adsorption has been preferred due to its simplicity, high removal efficiency, operational and implementation facility and low cost. This paper provides a systematic review of the published peer-reviewed literature concerned with caffeine removal by the adsorption process. The Scopus and ScienceDirect databases were used to identify relevant articles researches on caffeine removal. Many authors have studied caffeine's adsorption equilibrium in aqueous media, different conditions, and different adsorbents. This paper aims to uncover the overall trend of adsorbent used, kinetic and thermodynamic studies. The impact of pH, temperature, adsorbent dosage and competitive effect were presented and analyzed. It was observed that the adsorption capacities ranged between 10 and 1000 mg g^-1, according to the nature and properties of the adsorbent. The pseudo-second order (kinetic model) and the Langmuir isotherm model showed the best adjustment of the experimental data from caffeine adsorption in most studies. The mechanistic understanding of adsorption and the development of new adsorbents are still a matter of future research, as well as the use of other kinetic models based on statistical factors and the thermodynamic studies should be considered.

Enhanced dissipation of trace level organic contaminants by floating treatment wetlands established with two macrophyte species: A mesocosm study

This study evaluated removal efficiencies of six contaminants of emerging concern (CECs) in floating treatment wetland (FTW) mesocosms established with either Japanese Sweetflag (Acorus gramineus Sol. ex Aiton) or canna lilies (Canna Hybrida L. 'Orange King Humbert'). The CECs included: acetaminophen (APAP), atrazine (ATZ), carbamazepine (CBZ), perfluorooctanoic acid (PFOA), sulfamethoxazole (SMX), and 17β-estradiol (E2). Each treatment was planted with different numbers of plants (i.e., 0, 10, 15, and 20), and the experiments lasted for 17 weeks. Dissipation of CECs was greater in planted treatments than in non-planted controls, and the planting number had little effect on dissipation of CECs. All residues of APAP and E2 dissipated rapidly within 2 weeks in all planted treatments. At the end of the experiment, residues of ATZ and SMX completely dissipated in the canna treatments, but not in the sweetflag treatments (75.8-87.6% and 96.3-97.1%, respectively). During the 17 week study, moderate dissipation of CBZ was observed in treatments including cannas (79.5-82.6%) and sweetflag (69.4-82.3%), while less dissipation was observed for PFOA (9.0-15.0% with sweetflag and 58.4-62.3% with cannas). Principal component analysis indicates that aqueous persistency of CECs and species of plants used influenced the dissipation of CECs in FTWs. Of the two species evaluated, canna was the most promising plant species for FTW systems designed to remove these CECs from surface water.

Acclimatization of microbial community of submerged membrane bioreactor treating hospital wastewater

This study was performed to understand the dynamics of the microbial community of submerged membrane bioreactor during the acclimatization process to treat the hospital wastewater. In this regard, three acclimatization phases were examined using a mixture of synthetic wastewater (SWW) and real hospital wastewater (HWW) in the following proportions; In Phase 1: 75:25 v/v (SWW: HWW); Phase 2: 50:50 v/v (SWW: HWW); and Phase 3: 25:75 v/v (SWW: HWW) of wastewater. The microbial community was analyzed using Illumina high throughput sequencing to identify the bacterial and micro-eukaryotes community in SMBR. The acclimatization study clearly demonstrated that shift in microbial community composition with time. The dominance of pathogenic and degrading bacterial communities such as Mycobacterium, Pseudomonas, and Zoogloea was observed at the phase 3 of acclimatization. This study witnessed the major shift in the micro-eukaryotes community, and the proliferation of fungi Basidiomycota was observed in phase 3 of acclimatization.

Inhibitory mechanisms and fate of the analgesic drug acetaminophen in nitrifying activated sludge

This work investigated the inhibitory effects and fate of acetaminophen (N-acetyl-p-aminophenol, APAP) on activated sludge (AS) under nitrifying and aerobic conditions. APAP disrupted the two-step biological nitrification process in a dose-dependent manner. 100 mg/L APAP inhibited ammonia oxidation (the first step of nitrification) accompanied by a significant reduction (> 80 %) of Nitrosomonas oligotropha in relative abundance. 50 mg/L of APAP had no significant effects on ammonia oxidation but interrupted nitrite oxidation (the second step of nitrification) with more than 90 % reduction of Candidatus Nitrospira defluvii. APAP was removed in nitrifying activated sludge via largely the biotransformation route. Both nitrifiers and heterotrophic microorganisms contributed to overall APAP removal. An AS bioreactor was acclimated to 100 mg/L APAP as the sole source of carbon, nitrogen, and energy to enrich the microbial community with APAP-metabolizing heterotrophs. During acclimation, dynamic changes in community phenotypes occurred with significant reduction in species richness and diversity. Community acclimation significantly increased APAP biotransformation rates. 16S rRNA gene-based community profiling showed selective enrichment for Pseudomonas and Sphingomonas, both with demonstrated APAP metabolic capacity.

Occurrence, fate, and mass balance of selected pharmaceutical and personal care products (PPCPs) in an urbanized river

The identification and quantification of pharmaceutical and personal care products (PPCPs) in aquatic ecosystems is critical to further studies and elucidation of their fate as well as the potential threats to aquatic ecology and human health. This study used mass balances to analyse the sources, transformation, and transport of PPCPs in rivers based on the population and consumption habits of residents, the removal level of sewage treatment, the persistence and partitioning mechanisms of PPCPs, hydrological conditions, and other natural factors. Our results suggested that in an urbanized river of Guangzhou City, China, the daily consumption of PPCPs was the main reason for the variety of species and concentrations of PPCPs. Through the determination of PPCPs in the river water samples and a central composite design (CCD) methodology, the dominant elimination mechanisms of caffeine and carbamazepine from river water were photolysis and biodegradation, but that of triclosan was sorption rather than biodegradation. The mass data of 3 PPCPs were estimated and corroborated using the measured data to evaluate the accuracy of the mass balance. Finally, caffeine, carbamazepine and triclosan discharged from the Shijing River into the Pearl River accounted for 97.81%, 99.52%, and 28.00%, respectively, of the total mass of these three compounds in the surface water of Shijing River. The results suggest that photolysis are the main process of natural attenuation for selected PPCPs in surface waters of river systems, and the transfer processes of PPCPs is mainly attributed to riverine advection. In addition, the low concentration of dissolved oxygen inhibited the degradation of PPCPs in the surface water of Shijing River.

Occurrence and Spatiotemporal Dynamics of Pharmaceuticals in a Temperate-Region Wastewater Effluent-Dominated Stream: Variable Inputs and Differential Attenuation Yield Evolving Complex Exposure Mixtures

Effluent-dominated streams are becoming increasingly common in temperate regions and generate complex pharmaceutical mixture exposure conditions that may impact aquatic organisms via drug-drug interactions. Here, we quantified spatiotemporal pharmaceutical exposure concentrations and composition mixture dynamics during baseflow conditions at four sites in a temperate-region effluent-dominated stream (upstream, at, and progressively downstream from effluent discharge). Samples were analyzed monthly for 1 year for 109 pharmaceuticals/degradates using a comprehensive U.S. Geological Survey analytical method and biweekly for 2 years focused on 14 most common pharmaceuticals/degradates. We observed a strong chemical gradient with pharmaceuticals only sporadically detected upstream from the effluent. Seventy-four individual pharmaceuticals/degradates were detected, spanning 5 orders of magnitude from 0.28 to 13 500 ng/L, with 38 compounds detected in >50% of samples. "Biweekly" compounds represented 77 ± 8% of the overall pharmaceutical concentration. The antidiabetic drug metformin consistently had the highest concentration with limited in-stream attenuation. The antihistamine drug fexofenadine inputs were greater during warm- than cool-season conditions but also attenuated faster. Differential attenuation of individual pharmaceuticals (i.e., high = citalopram; low = metformin) contributed to complex mixture evolution along the stream reach. This research demonstrates that variable inputs over multiple years and differential in-stream attenuation of individual compounds generate evolving complex mixture exposure conditions for biota, with implications for interactive effects.

Activated sludge-degrading analgesic drug acetaminophen: Acclimation, microbial community dynamics, degradation characteristics, and bioaugmentation potential

This study identified specific bacterial populations that play a key role in detoxifying acetaminophen (N-acetyl-p-aminophenol, APAP) in activated sludge (AS) microbial communities. An AS bioreactor was established by feeding 100 mg/L of APAP as a sole carbon, nitrogen, and energy source. While the bioreactor increased APAP biotransformation rates significantly (0.7 d^-1 to 6.1 d^-1) over a month of acclimation, it selected for Pseudomonas by significantly reducing community diversity by 40% and richness by 47%. A Pseudomonas population (designated PCO) isolated from the APAP-degrading community was phylogenetically distinct from other Pseudomonas spp. previously reported as APAP-degrading isolates. PCO could remove APAP at levels up to 590 mg/L without inhibition and could also metabolize APAP-derived metabolites, 4-aminophenol, hydroquinone, and 1,4-benzoquinone at varying levels. PCO was introduced to AS at various volumes (5, 25, and 50% of the total), showing significantly enhanced APAP transformation rates (1.5, 1.9, and 2.3 d^-1) compared to the control (1.2 d^-1) without PCO inoculation. Overall, our study provides new insights into the phylogenetic and metabolic features of a key species population predominantly accelerating APAP breakdown in the context of AS microbial communities, which will help in the design of a biological means (bioaugmentation) of treating APAP-bearing waste streams.

Construction waste as substrate in vertical subsuperficial constructed wetlands treating organic matter, ibuprofenhene, acetaminophen and ethinylestradiol from low-strength synthetic wastewater

This study aimed to evaluate the removal of chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), total ammonia nitrogen (TAN), total phosphorus (TP), ibuprofen, acetaminophen and ethinylestradiol of synthetic effluent simulating low-strength sewage by sequencing-batch mode constructed wetlands (CWs). To verify the feasibility of using a floating macrophyte in CWs and compare different substrates, three CWs containing light expanded clay aggregates (CWL), expanded clay with porcelain tiles (CWLP) and bricks (CWB) were planted with Pistia stratiotes. The results showed that CWB achieved the highest removals of TKN (78%), TAN (70%) and TP (46%), and CWLP achieved the highest COD removal (75%). LECA favored the removal of ibuprofen (92%, p < 0.05) when compared to bricks (77%), probably by the combination of biodegradation and sorption in the systems. The highest acetaminophen removal (71% to 96%) was observed in CWL, probably via biodegradation, but no significant differences were found between the CWs (p > 0.05). Ethinylestradiol was removed 76% in CWLP and 73% in CWB, both differing statistically from CWL (p < 0.05), demonstrating that brick and the combination of clay with porcelain were better than just clay in this hormone removal. After 188 days of operation, P. stratiotes was able to uptake nitrogen and phosphorus of approximately 0.28 g and 0.25 g in CWL, 0.33 g and 0.21 g CWLP, and 0.22 g and 0.09 g in CWB of, respectively. Adsorption of nitrogen and phosphorus onto the substrates was 0.48 g and 6.84 g in CWL, 0.53 g and 5.69 g in CWLP, and 0.36 g and 10.18 g in CWB, respectively. The findings on this study suggest that adsorption was possible the main process for TP removal onto the evaluated substrates whereas microbial activity was the most probable mechanism for TN removal in the evaluated CW systems.

Potential use of floating treatment wetlands established with Canna flaccida for removing organic contaminants from surface water

Surface water bodies worldwide may be contaminated with various organic contaminants. In many cases, the actual toxicity thresholds to nontarget organisms are unknown, thus presenting unknown risks. This study evaluated the potential use of floating treatment wetlands (FTWs) planted with Canna flaccida (common name: Canna) for removing two pharmaceuticals (acetaminophen and carbamazepine) and one herbicide (atrazine) from contaminated water. Triplicate FTWs with varying plant densities were established in 378 L mesocosms. After dosing the mesocosms with the contaminants, water samples were collected over a 12-week period for analysis. The planted FTWs showed differing abilities for removing acetaminophen, atrazine, and carbamazepine. Plant densities on the FTWs did not affect dissipation of acetaminophen or atrazine, but did carbamazepine. All acetaminophen residues were removed from the water within 2 weeks, while all atrazine residues were removed within 12 weeks. Approximately, 79-92% of these residues removed were associated with the FTWs. In contrast, all of the carbamazepine was not removed after 12 weeks, at which time only 29-36.7% of the total removed was associated with the FTWs. Overall results suggest that FTWs established with C. flaccida are promising for removing trace concentrations of acetaminophen, atrazine, and carbamazepine from surface water.

Influence of hydrologic and anthropogenic drivers on emerging organic contaminants in drinking water sources in the Susquehanna River Basin

Occurrence of emerging organic contaminants (EOCs) in surface water bodies can cause adverse effects on non-target organisms. When surface waters are used as drinking water sources, temporal variability in EOC concentrations can potentially impact drinking water quality and human health. To better understand spatiotemporal variability of EOCs in drinking water sources in Central Pennsylvania, EOCs were evaluated in six drinking water sources during a two-year study period (April 2016-June 2018) in the Susquehanna River Basin (SRB). The study was conducted in two phases: Phase I was a spatially distributed sampling approach within the SRB focusing on seven human pharmaceuticals and Phase II was a temporally intensive sampling regime at a single site focusing on a broader range of EOCs. Concentration-discharge relationships were utilized to classify EOC transport dynamics and understand the extent to which hydrologic and anthropogenic factors, such as surface runoff and wastewater effluent, may contribute to EOC occurrence. Overall, EOCs were present at higher concentrations in colder seasons than warmer seasons. Thiamethoxam, a neonicotinoid insecticide, and caffeine exhibited accretion dynamics during high-flow periods, suggesting higher transport during surface runoff events. Human pharmaceuticals known to persist in wastewater effluent were inversely correlated with discharge, indicating dilution characteristics consistent with diminished wastewater signals during high-flow periods. Acetaminophen exhibited near-chemostatic transport dynamics, indicating nonpoint source inputs during high-flow periods. Risk calculations revealed that although EOCs posed medium-to-high risk to aquatic organisms, human health risk through fish consumption was low.

Characterization of the Nairobi River catchment impact zone and occurrence of pharmaceuticals: Implications for an impact zone inclusive environmental risk assessment

The largely uncontrolled release of active pharmaceuticals ingredients (APIs) within untreated wastewater discharged to waterbodies, associated with many rapidly urbanising centres is of growing concern owing to potential antimicrobial resistance, endocrine disruption and potential toxicity. A sampling campaign has been undertaken to assess the source, occurrence, magnitude and risk associated with APIs and other chemicals within the Nairobi/Athi river basin, in Kenya, East Africa. The catchment showed an extensive downstream impact zone estimated to extend 75 km, mostly, but not exclusively, derived from the direct discharge of untreated wastewater from the urban centre of Nairobi city. The exact extent of the downstream boundary of the Nairobi city impact zone was unclear owing to the inputs of untreated wastewater sources from the continuous urbanized areas along the river, which counteracted the natural attenuation caused by dilution and degradation. The most frequently detected APIs and chemicals were caffeine, carbamazepine, trimethoprim, nicotine, and sulfamethoxazole. Paracetamol, caffeine, sulfamethoxazole, and trimethoprim alone contributed 86% of the total amount of APIs determined along the Nairobi/Athi catchment. In addition to direct discharge of untreated domestic wastewater attributed to the informal settlements within the conurbation, other sources were linked to the industrial area in Nairobi City where drug formulation is known to occur, the Dandora landfill and veterinary medicines from upstream agriculture. It was shown that there was a possible environmental risk of API ecotoxicological effects beyond the end of the traditional impact zone defined by elevated biochemical oxygen demand concentrations; with metronidazole and sulfamethoxazole exhibiting the highest risk.

Distribution, Removal, and Risk Assessment of Pharmaceuticals and Their Metabolites in Five Sewage Plants

The extensive use of pharmaceuticals and personal care products (PPCPs) leads to a continuous increase of their presence in urban wastewater. These pollutants are discharged into natural waters and pose a threat to human health and the ecological environment. This study focused on five sewage treatment plants in three cities of China’s Yangtze River Delta as research sites to study the distribution and degradation of drugs and their conversion products in wastewater. The concentration of target compounds in the water ranged from 0 to 510.8 ng/L, and both positive and negative removal rates occurred during the treatment. Acetaminophen (ACE) and ibuprofen (IPF) can be completely removed in the biological treatment stage. The addition of flocculants and sand filtration has a positive effect on the removal of naproxen (NPX) and bezafibrate (BZB). Ultraviolet disinfection is beneficial for the removal of antipyrine (ATP) and diclofenac (DCF). A small amount of PPCPs were found in the sludge and particulate matter, which had little effect on removal. Finally, the risk quotients were used to evaluate the harmfulness of the PPCPs detected in the effluent to the ecological environment, and the results showed that there was little hazard.

Removal and monitoring acetaminophen-contaminated hospital wastewater by vertical flow constructed wetland and peroxidase enzymes

Hospital wastewater contains acetaminophen (ACT) and nutrient, which need adequate removal and monitoring to prevent impact to environment and community. This study developed a pilot scale vertical flow constructed wetland (CW) to (1) remove high-dose ACT and pollutants in hospital wastewater and (2) identify the correlation of peroxidase enzyme extruded by Scirpus validus and pollutants removal efficiency. By that correlation, a low-cost method to monitor pollutants removal was drawn. Plants, such as Scirpus validus, generated peroxidase enzymes to alleviate pollutants' stress. Results showed that the CW removed 3.5 to 6 logs of initial concentration 10 mg ACT/L to a recommended level for drinking water. The CW eliminated COD, TKN and TP efficiently, meeting the wastewater discharged standards of Thailand and Vietnam. By various multivariable regression models, concentrations of ACT in CW effluent and enzymes in S. validus exhibited a significant correlation (p < 0.01, R² = 68.3%). These findings suggested that (i) vertical flow CW could remove high-dose ACT and nutrient and (ii) peroxidase enzymes generated in S. validus, such as soluble and covalent ones, could track ACT removal efficiency. This would help to reduce facilities and analytical cost of micro-pollutants.

Occurrence of PPCPs in a Brazilian water reservoir and their removal efficiency by ecological filtration

The presence of PPCPs (Pharmaceuticals and Personal Care Products) in water sources and drinking water has concerned researchers in recent times. This study was carried out to evaluate the occurrence of 6 PPCPs (namely paracetamol, diclofenac, naproxen, ibuprofen, benzophenone-3 and methylparaben) in the Lobo reservoir, their degradation products, and how efficiently they were removed by 22 ecological filters, considering individual and mixture of compounds. There were 3 spiking events of PPCPs (2 μg L^-1) in the ecological filter influents conducted with a lag period of 15 days between spikes. Water samples were collected from the influent and effluent of the filters at 3, 6 and 24 h after each spiking event. All target PPCPs were identified in the Lobo reservoir water in the range of μg L^-1. The personal care products were detected with 100% frequency in the samples, and in higher concentrations compared to the pharmaceuticals. Degradation products of diclofenac and benzophenone-3 were identified in the water samples. Results of this investigation show that ecological filtration was an effective process (70-99%) to remove 2 μg L^-1 of the selected PPCPs, and demonstrated that the filters were resilient to individual compounds and to their mixtures.

Impact of the wastewater-mixing zone on attenuation of pharmaceuticals in natural waters: Implications for an impact zone inclusive environmental risk assessment

The direct discharge of untreated wastewater has been identified as an important source of environmental contamination by active pharmaceutical ingredients and other 'down-the-drain' chemicals in developing countries. It necessitates the development of an environmental risk assessment approach for the resulting impact zone. This study was designed to investigate the impact of low level of dilution (<10) on the natural attenuation processes of distribution and degradation within the impact zone. Dilution of the untreated wastewater resulted in increased desorption and corresponding environmental concentrations. The presence/absence of the microbial population in the batches affected the degree of sorption depending on the compound charge (i.e. positive or negative), highlighting an experimental technical bias. The degradation half-lives of acebutolol and diclofenac increased with increasing dilution and resulted in higher environmental persistence. The modelling of the biochemical oxygen demand (BOD) allowed an estimate of the temporal end boundary of the impact zone to be predicted as 24h. Therefore, it was concluded that most of the investigated compounds would persist beyond the end of the impact zone as defined by the return to environmental BOD concentrations. It is proposed that, within environmental risk assessment protocols, the impact zone should be considered as a semi-natural wastewater treatment area in such a way to allow the estimate of environmental concentrations of pharmaceuticals beyond its end.

Integrated assessment of sediment contaminant levels and biological responses in sentinel fish species Atherinella brasiliensis from a sub-tropical estuary in south Atlantic

This study combined data of the concentrations of metals, polycyclic aromatic hydrocarbons (PAHs) and pharmaceuticals and personal hygiene products (PPCPs) in the sediments and the biological responses of the Atherinella brasiliensis fish in two different sites and climate seasons in the Estuarine-Lagoon Complex of Iguape-Cananéia, Southeast Brazil. The presence of metals, PAHs, and PPCPs were observed in the sediments demonstrating the contamination throughout the system with contributions of sewage and residues disposal, oil and combustion of biomass and fossil fuels. Higher contaminations were identified in the point of greater human presence (C - Cananéia City), especially during the cold-dry season. The influence of anthropic activities and variations in the estuarine conditions, such as lower hydrodynamics during the lower rainfall period, were observed. In fish, spatial and seasonal changes in the parameters of oxidative stress and biotransformation, genotoxicity and histopathological alterations followed the same trend, with more pronounced responses in C in the cold-dry season. The biological responses of the fish revealed adverse effects in the local species population and indicated the presence of metals, PAHs and PPCPs as stressors. The multivariate analysis and the integrated biomarker response index (IBR) corroborated with these results, also indicating that site C had the worst environmental quality. The present study provides new information about the contamination of the sediments of Estuarine-Lagoon Complex of Iguape-Cananéia and the chronic exposure to contaminants in A. brasiliensis. Therefore, contributing to a better understanding of the local environmental quality with data that can support protective management of the area.

Contamination patterns and attenuation of pharmaceuticals in a temporary Mediterranean river

The contamination patterns and fate of pharmaceutically active compounds (PhACs) were investigated in the Evrotas River (Southern Greece). This is a temporary river with differing levels of water stress and water quality impairment in a number of its reaches. Three sampling campaigns were conducted in order to capture different levels of water stress and water quality. Four sampling sites located on the main channel of the Evrotas River were sampled in July 2015 (moderate stream flow), and June and September 2016 (low stream flow). Discharge of urban wastewater has been determined as the main source of pollution, with PhACs, nutrients and other physicochemical parameters considerably increasing downstream the wastewater treatment plant (WWTP) of Sparta city. Due to the pronounced hydrological variation of the Evrotas River, generally, the highest concentrations of PhACs have been detected during low flow conditions. Simultaneously, low flow resulted in an increased water travel time and consequently longer residence time that accounted for the higher attenuation of most PhACs. The average decrease in total concentration of PhACs within the studied waterbody segment (downstream of Sparta city) increased from 22% in July 2015 to 25% in June 2016 and 77% in September 2016. The PhACs with the highest average concentration decrease throughout the sampling campaigns were hydrochlorothiazide, followed by sotalol, carbamazepine, valsartan, and naproxen.

Fate of five pharmaceuticals under different infiltration conditions for managed aquifer recharge

Infiltration of treated wastewater (TWW) to recharge depleted aquifers, often referred to as managed aquifer recharge, is a solution to replenish groundwater resources in regions facing water scarcity. We present a mass balance approach to infer the amounts of five pharmaceuticals (carbamazepine, diclofenac, fenoprofen, gemfibrozil, and naproxen) degraded in column experiments based on concentrations of pharmaceuticals in the aqueous and solid (sorbed) phases. Column experiments were conducted under three different conditions: continuous infiltration, wetting and drying cycles, and wetting and drying cycles with elevated concentrations of antibiotics (which may reduce microbially aided degradation of other compounds). A mass balance comparing pharmaceutical mass in the water phase over the 16-month duration of the experiments to mass sorbed to the soil was used to infer the mass of pharmaceuticals degraded. Results show sorption as the main attenuation mechanism for carbamazepine. About half of the mass of diclofenac was degraded with wetting and drying cycles, but no significant degradation was found for continuous infiltration, while 32% of infiltrated mass sorbed. Fenoprofen was degraded in the shallow and aerobic part of the soil, but degradation appeared to cease beyond 27 cm depth. Gemfibrozil attenuated through a combination of degradation and sorption, with slight increases in attenuation with depth from both mechanisms. Naproxen degraded progressively with depth, resulting in attenuation of >90% of the mass. In the column with elevated concentrations of antibiotics, the antibiotics attenuated to about 50% or less of inflow concentrations by 27 cm depth and within this zone, less degradation of the other compounds was observed.

The accelerated biodegradation and mineralization of acetaminophen in the H2O2-stimulated upflow fixed-bed bioreactor (UFBR)

The biodegradation and mineralization of acetaminophen (ACT) was evaluated in the upflow fixed-bed bioreactor (UFBR) inoculated with a biomass containing mixture of Pseudomonas spp. and Bacillus spp. as the dominant bacteria under H₂O₂ stimulation. The effect of various main operational variables was evaluated on the performance of the UFBR for ACT removal. The maximum ACT removal was obtained at the H₂O₂:ACT molar ratio of 14. H₂O₂ induced the bacteria in biofilm for the in-situ generation of peroxidase resulted in the acceleration of ACT decomposition into more biodegradable intermediates. Over 99% of ACT and 72% of its TOC at initial ACT concentrations up to 300 mg/L could be eliminated under optimum H₂O₂:ACT molar ratio in the batch UFBR within 12 h recirculation time. The specific biodegradation rate of ACT increased from 1.0 to 4.1 mg ACT/g_biomass.h when the inlet loading rate was increased from 8.3 to 41.7 g ACT/m³.h. In addition, the complete biodegradation and TOC removal of ACT was observed in the continuous UFBR at the hydraulic retention time of 6 h and the presence of 1-20 g/L salinity without inhibition. The presence of H₂O₂ could efficiently stimulate the production of bacterial peroxidase, which in turn resulted in the acceleration of ACT biodegradation and mineralization. Therefore, the H₂O₂-stimulated UFBR is an efficient and viable technique for in-situ production of peroxidase used for acceleration of ACT biodegradation.

Combining sorption experiments and Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to study the adsorption of propranolol onto environmental solid matrices - Influence of copper(II)

The bioavailability of pharmaceuticals is governed by their sorption in soils/sediments, as the retention processes determine their concentration in surface- and ground-water. The adsorption of these contaminants can involve various solid components such as organic matter, clays and metallic oxides, and their distribution among these solid components depends on contaminant and solid properties. In this paper we studied the adsorption of the pharmaceutical propranolol - a beta-blocker - on eight different solids (six soils, one sediment and one kaolinite-based sample) by batch experiments. The influence of contact time, propranolol concentration and pH was considered, as well as the presence of copper(II). The investigated solids displayed a wide variability in terms of CEC (cationic exchange capacity) and organic carbon and carbonates contents. The influence of pH was negligible in the pH range from 5.5 to 8.6. The adsorbed amounts were greatly dependent on the solid and two groups of solids were evidenced: three soils of high CEC and organic carbon contents which retained high amounts of propranolol, and three soils, the sediment and the kaolinite-based sample (low CEC and organic carbon content) displaying a low adsorption capacity for the beta-blocker. A linear model enabling the determination of the sorption parameters K_d and K_oc was pertinent to describe the adsorption isotherms but the K_oc values showed a great variability. It was shown that organic carbon content alone could not explain propranolol adsorption. The CEC value was identified as influent parameter and a simple empirical model was proposed to describe propranolol adsorption. At microscopic and molecular scales, ToF-SIMS experiments indicated (i) a decrease of potassium on the surface upon propranolol adsorption with a distribution of the beta-blocker similarly to alumino-silicates, iron and organic carbon on the surface confirming a cation exchange mechanism and (ii) the absence of degradation products and copper-propranolol complexes.

Characteristics of removal of waste-water marking pharmaceuticals with typical hydrophytes in the urban rivers

The investigations on their variation and distribution of 13 called waste-water marking pharmaceuticals (WWMPs) were conducted under 4 hydrophyte conditions (without plants, with submerged aquatic plant (Myriophyllum verticillatum L.), emergent aquatic plant cattail (Typha orientalis Presl) and floating aquatic plant (Lemna minor L.)) in a simulated urban river system. By the calculation of mass balance, the quantitative distribution of WWMPs in water phase, sediment and plant tissues was identified, and the overall removal efficiencies of target pharmaceuticals in the whole system could be determined. Without plants, high persistence of atenolol (ATL) (97.7%), carbamazepine (CBM) (102.8%), clofibric acid (CLF) (101.8%) and ibuprofen (IBU) (80.9%) was detected in water phase, while triclosan (TCS) (53.5%) displayed strong adsorption affinity in sediment. The removal under the planted conditions was considerably raised, compared with no plant condition for most WWMPs. However, TCS did not show obvious differences among the hydrophyte conditions due to its strong adsorption affinity and high hydrophobicity. The relatively higher removal was found for the hydrophilic (logK_ow<1) or moderately hydrophobic (1<logK_ow<3) pharmaceuticals with submerged and emergent aquatic plants. The highly hydrophobic pharmaceuticals (logK_ow>4.0) did not show significant differences among the whole tests in sediment. Mass balance calculation displayed the removal of CBM (5.6%-13.6%), CLF (4.0%-17.8%) and caffeine (8.4%-17.2%) through the plant uptake was relatively higher. For the rest WWMPs, only small parts (<6.0%) of the initial concentrations were found in plant tissues. The higher removal efficiencies of most WWMPs under the planted conditions indicated that aquatic plants indeed played an important role in the removal of WWMPs although the direct uptakes might not be a dominant pathway to the overall removal of WWMPs. Besides, the floating aquatic plant removed most WWMPs from the water phase efficiently. In contrast, submerged and emergent aquatic plants could effectively remove them in sediment.

The application of GAC sandwich slow sand filtration to remove pharmaceutical and personal care products

Lab-scale GAC sandwich slow sand filters with different GAC layer depths were evaluated for the first time to remove selected pharmaceutical and personal care products (PPCPs) (namely DEET, paracetamol, caffeine and triclosan, 25 μg/L). Coarse sand (effective grain size of 0.6 mm) was used instead of conventional fine sand. In addition to single sand and GAC filters, GAC sandwich filters were assessed at three filtration rates (i.e. 5 cm/h, 10 cm/h and 20 cm/h) to compare removals. Sandwich filter with 20 cm GAC achieved the best average PPCP removal (98.2%) at 10 cm/h rate. No significant difference of average PPCP removal was found between 10 and 20 cm/h filtration rates for the three GAC sandwich filters (p > 0.05). Among the selected PPCPs, DEET, the recalcitrant compound, was most effectively removed by the GAC sandwich filters. Combining the GAC layers with the slow sand filters significantly enhanced the removal of the target PPCP compounds (p < 0.05), demonstrating that both adsorption and biodegradation contributed to the removals. Furthermore, pseudo-second-order equation (Type 1) could best represent the adsorption kinetics of the four target PPCP compounds onto GAC. In relation to other quality parameters, sandwich filter with 20 cm of GAC also showed good average removals of chemical oxygen demand (COD) of 65.8% and total organic carbon (TOC) of 90.3%, but occurrence of ammonium up to 0.76 mg/L concentration indicated inapplicability of filtration rate of 5 cm/h. No significant difference was found between 10 cm/h and 20 cm/h filtration rates for nitrogen and phosphate removals (p > 0.05). Results of this lab-scale investigation show that GAC sandwich slow sand filter is potentially an effective process for removing PPCPs from tertiary wastewater.

Assessment of the environmental fate of endocrine disrupting chemicals in rivers

Laboratory tests were conducted with five endocrine disruptors (bishenol A, triclosan. nonylphenol, nonylphenol monoethoxylate and nonylphenol diethoxylate) under different redox conditions (aerobic, anoxic, anaerobic and sulfate-reducing conditions) to assess abiotic and biotic degradation in a river water/sediment system. The river water sample was collected from Spercheios River while the sediment was collected from the banks of a tributary of the river at the point where the discharge point of a wastewater treatment plant is located. To describe quantitatively elimination kinetics of the target compounds, pseudo first-order kinetics were adopted. According to the results from the microcosms studies, it can be stated that the substances are eliminated from the aqueous phase with relatively high rates under aerobic conditions due to both sorption and biotransformation processes. However, when reduced oxygen conditions were established in the microcosms incubations, biotransformation decreased, indicating the almost complete cease of the EDCs microbial degradation, while substances' sorption onto sediments showed no significant differences. All compounds were found to be biodegradable under aerobic conditions, and the low to high order of the calculated dissipation rate constants was 0.064±0.004d^-1 (TCS)→0.067±0.006d^-1 (NP)→0.076±0.009d^-1 (NP2EO)→0.081±0.007d^-1 (NP1EO)→0.103±0.011d^-1 (BPA). Finally, regarding the biotransformation experiments, the elimination of the compounds limited in the absence of oxygen as compared to aerobic.

Sorption of active pharmaceutical ingredients in untreated wastewater effluent and effect of dilution in freshwater: Implications for an "impact zone" environmental risk assessment approach

Evidence of ecotoxicological effects of active pharmaceuticals ingredients (APIs) has increased research into their environmental fate. In low and low-middle income countries (LLMICs) the main source of APIs to surface waters is from discharge of untreated wastewater. Consequently, concentrations of APIs can be relatively high in the "impact zone" downstream of a discharge point. Little is known about the fate of APIs in these impact zones. In this laboratory scale investigation, the effect of successive dilution of synthetic untreated wastewater (dilution factor 1 to 10) on the distribution of APIs was studied. The sorption was consistent with the chemical properties of each compound: charge, lipophilicity, and structure. Dilution increased desorption of the basic and neutral APIs (up to 27.7%) and correlated with their lipophilicity (R²>0.980); the positive charge was of secondary importance. Anions did not significantly desorb (<10% loss). Increased concentrations of dissolved organic matter at dilutions of 8 and 10 times that of untreated wastewater coincided with lower dissolved API concentrations. The data showed a clear trend in the desorption process of APIs that may lead to higher exposure risk than anticipated. Therefore, it is suggested that these aspects should be accounted for in the development of dedicated environmental risk assessment approach for APIs in riverine impact zones of LLMICs countries.

Sorption and biodegradation of six pharmaceutically active compounds under four different redox conditions

This study explored the removal of six pharmaceutically active compounds (PhACs) in lab-scale experiments with sediments under four redox conditions, namely aerobic, nitrate reducing, sulfate reducing, and methanogenic conditions using batch and column set-ups. Redox conditions were found to influence PhAC removal by sorption and biodegradation. The most optimal PhAC removal was observed at the outer ranges of the redox spectrum, i.e. either aerobic or deep anaerobic (sulfate reducing and methanogenic conditions), whereas nitrate reducing conditions were found least effective for PhACs biodegradation and sorption. For instance, sorption coefficient K_d values for metoprolol in column experiments were 90, 65, 42 and 11 L/kg for sulfate reducing, methanogenic, aerobic and nitrate reducing conditions, respectively. For the same conditions K_d values for propranolol were 101, 94, 55 and 55 L/kg, respectively. As expected, biodegradation efficiencies were highest under aerobic conditions, showing >99% removal of caffeine and naproxen, but no removal for propranolol and carbamazepine. The adaptive capacity of sediment was demonstrated by pre-exposure to PhACs leading to improved PhAC biodegradation. The results of this study indicate the necessity to combine diverse redox conditions, including aerobic conditions, for maximizing PhAC removal by sorption and biodegradation. Furthermore, our findings stress the need for additional treatment measures as recalcitrant PhACs are not effectively removed under any redox condition.