Antiviral drugs in aquatic environment and wastewater treatment plants: A review on occurrence, fate, removal and ecotoxicity

A sustainable approach for the removal methods and analytical determination methods of antiviral drugs from water/wastewater: A review

In the last years, antiviral drugs especially used for the treatment of COVID-19 have been considered emerging contaminants because of their continuous occurrence and persistence in water/wastewater even at low concentrations. Furthermore, as compared to antiviral drugs, their metabolites and transformation products of these pharmaceuticals are more persistent in the environment. They have been found in environmental matrices all over the world, demonstrating that conventional treatment technologies are unsuccessful for removing them from water/wastewater. Several approaches for degrading/removing antiviral drugs have been studied to avoid this contamination. In this study, the present level of knowledge on the input sources, occurrence, determination methods and, especially, the degradation and removal methods of antiviral drugs are discussed in water/wastewater. Different removal methods, such as conventional treatment methods (i.e. activated sludge), advanced oxidation processes (AOPs), adsorption, membrane processes, and combined processes, were evaluated. In addition, the antiviral drugs and these metabolites, as well as the transformation products created as a result of treatment, were examined. Future perspectives for removing antiviral drugs, their metabolites, and transformation products were also considered.

The efficacy of the VUV/O3 process run in a continuous-flow fluidized bed reactor for simultaneous elimination of favipiravir and bacteria in aqueous matrices

The efficacy of the Vacuum UV/Ozonation (VUV/O₃) process was evaluated for the degradation of favipiravir (FAV). It was found that coupling O₃ and VUV resulted in a considerable synergistic catalytic effect on FAV removal. The VUV/O₃ process performed better in moderately alkaline conditions than in acidic ones; complete FAV degradation and 99.4% TOC removal were achieved within 10 and 60 min, respectively. HO^• played the dominant role in FAV degradation, with a second-order reaction rate constant with HO^• at 1.05 × 10¹⁰ M^-1 s^-1. The VUV/O₃ process could effectively treat tap water spiked with FAV. Efficient FAV and TOC removal, as well as total bacterial inactivation, was attained when treating municipal secondary effluent by the VUV/O₃ process. Finally, the VUV/O₃ process was operated in a continuous-flow mode in a fluidized-bed (FBR) reactor for treating FAV-spiked tap water. Complete degradation and 75.1% mineralization of 10 mg/L FAV were obtained at a hydraulic retention time of 1 and 8 min, respectively. The findings clearly suggest that the VUV/O₃ process operated in a continuous-flow FBR is a promising, efficient technology for the removal of novel and emerging contaminants, such as the antiviral FAV.

Highly efficient decontamination of tetracycline and pathogen by a natural product-derived Emodin/HAp photocatalyst

To address the water pollution induced by pharmaceuticals, especially antibiotics, and pathogens, natural product emodin, a traditional Chinese medicine with the characteristic large π-conjugation anthraquinone structure, was used to rationally develop a novel Emodin/HAp photocatalyst by integrating with a thermally stable and recyclable support material hydroxyapatite (HAp) through a simple preparation method. It was found that its photocatalytic activity to generate reactive oxygen species (ROS) was greatly improved due to the migration of photogenerated electrons and holes between emodin and HAp upon visible light irradiation. Thus, this Emodin/HAp photocatalyst not only quickly photodegraded tetracycline with 99.0% removal efficiency but also exhibited complete photodisinfection of pathogenic bacteria Staphylococcus aureus upon visible light irradiation. Therefore, this study offers a new route for the design and preparation of multifunctional photocatalysts using widely available natural products for environmental remediation.

Decentralized systems for the treatment of antimicrobial compounds released from hospital aquatic wastes

In many developing countries, untreated hospital effluents are discharged and treated simultaneously with municipal wastewater. However, if the hospital effluents are not treated separately, they pose concerning health risks due to the possible transport of the antimicrobial genes and microbes in the environment. Such effluent is considered as a point source for a number of potentially infectious microorganisms, waste antimicrobial compounds and other contaminants that could promote antimicrobial resistance development. The removal of these contaminants prior to discharge reduces the exposure of antimicrobials to the environment and this should lower the risk of superbug development. At an effluent discharge site, suitable pre-treatment of wastewater containing antimicrobials could maximise the ecological impact with potentially reduced risk to human health. In addressing these points, this paper reviews the applications of decentralized treatment systems toward reducing the concentration of antimicrobials in wastewater. The most commonly used techniques in decentralized wastewater treatment systems for onsite removal of antimicrobials were discussed and evidence suggests that hybrid techniques should be more useful for the efficient removal of antimicrobials. It is concluded that alongside the cooperation of administration departments, health industries, water treatment authorities and general public, decentralized treatment technology can efficiently enhance the removal of antimicrobial compounds, thereby decreasing the concentration of contaminants released to the environment that could pose risks to human and ecological health due to development of antimicrobial resistance in microbes.

Ultraviolet-coupled advanced oxidation processes for anti-COVID-19 drugs treatment: Degradation mechanisms, transformation products and toxicity evolution

Remdesivir (RDV), dexamethasone (DEX) and hydroxychloroquine (HCQ) were widely used in the treatment of COVID-19 pneumonia, possibly causing environmental risks and drug-resistance viruses. This study elucidated the degradation mechanisms and potential toxicity risks of the three anti-COVID-19 drugs by UV and ultraviolet-coupled advanced oxidation processes (UV/AOPs). All the drugs could be degraded by more than 98% within 3 min under the following optimal conditions: pH of 5.0 and drug-to-oxidant (H₂O₂) molar ratio of 1:200. Combined with density functional theory (DFT) analysis and high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS), twenty-four transformation products (TPs) were detected and the main degradation pathways were investigated. Based on bacterial luminescence inhibition test and the peak-area evolution of TPs, RDV and HCQ showed an obvious toxicity-increase region when TPs were generated in large quantities, while the toxicity of DEX continued to decline during degradation processes. By QSAR predictions, the main contributors to the toxicity evolution during the UV/AOPs were predicted. Halogen-containing TPs showed significantly higher toxicity than other TPs, and thus the chlorine-containing structure in HCQ presented the potential toxicity. Appropriate reaction parameters and adequate reaction time for the UV/AOPs could eliminate the toxicity of TPs and ensure environmental safety. This study could play a positive role in the treatment of anti-COVID-19 drugs and their environmental hazard assessment.

SARS-CoV-2 pharmaceutical drugs: a critical review on the environmental impacts, chemical characteristics, and behavior of advanced oxidation processes in water

This review summarizes research data on the pharmaceutical drugs used to treat the novel SARS-CoV-2 virus, their characteristics, environmental impacts, and the advanced oxidation processes (AOP) applied to remove them. A literature survey was conducted using the electronic databases Science Direct, Scopus, Taylor & Francis, Google Scholar, PubMed, and Springer. This complete research includes and discusses relevant studies that involve the introduction, pharmaceutical drugs used in the SARS-CoV-2 pandemic: chemical characteristics and environmental impact, advanced oxidation process (AOP), future trends and discussion, and conclusions. The results show a full approach in the versatility of AOPs as a promising solution to minimize the environmental impact associated with these compounds by the fact that they offer different ways for hydroxyl radical production. Moreover, this article focuses on introducing the fundamentals of each AOP, the main parameters involved, and the concomitance with other sources and modifications over the years. Photocatalysis, sonochemical technologies, electro-oxidation, photolysis, Fenton reaction, ozone, and sulfate radical AOP have been used to mineralize SARS-CoV-2 pharmaceutical compounds, and the efficiencies are greater than 65%. According to the results, photocatalysis is the main technology currently applied to remove these pharmaceuticals. This process has garnered attention because solar energy can be directly utilized; however, low photocatalytic efficiencies and high costs in large-scale practical applications limit its use. Furthermore, pharmaceuticals in the environment are diverse and complex. Finally, the review also provides ideas for further research needs and major concerns.

Bioaccumulation of abacavir and efavirenz in Rhinella arenarum tadpoles after exposure to environmentally relevant concentrations

Antiretrovirals are pharmaceuticals used in the treatment of the human immunodeficiency virus; they are contaminants of emerging concern that have received considerable attention in recent decades due to their potential negative environmental effects. Data on the bioaccumulation and possible environmental risks posed by these drugs to aquatic organisms are very scarce. Therefore, the aim of this study was to evaluate the bioaccumulation of abacavir and efavirenz in Rhinella arenarum tadpoles subjected to acute static toxicity tests (96 h) at environmentally relevant concentrations. The analytical procedure consisted of the development and optimization of a method involving ultra-high performance liquid chromatography with tandem mass spectrometry detection. The instrumental conditions, optimized by design of experiments using the response surface methodology, yielded limits of detection of 0.3 μg L^-1 for abacavir and 0.9 μg L^-1 for efavirenz; and limits of quantification of 1.9 μg L^-1 for abacavir and 5.6 μg L^-1 for efavirenz. Subsequently, the bioaccumulation of the pharmaceutical drugs in tadpoles was evaluated at three exposure concentrations. Efavirenz displayed the highest bioaccumulation levels. This study shows the bioaccumulation potential of abacavir and efavirenz in amphibian tadpoles at exposure concentrations similar to those already detected in the environment, indicating an ecological risk for R. arenarum and probably other aquatic organisms exposed to these drugs in water bodies.

Effects of Two Antiretroviral Drugs on the Crustacean Daphnia magna in River Water

Antiretroviral (ARVs) drugs are used to manage the human immunodeficiency virus (HIV) disease and are increasingly being detected in the aquatic environment. However, little is known about their effects on non-target aquatic organisms. Here, Daphnia magna neonates were exposed to Efavirenz (EFV) and Tenofovir (TFV) ARVs at 62.5–1000 µg/L for 48 h in river water. The endpoints assessed were mortality, immobilization, and biochemical biomarkers (catalase (CAT), glutathione S-transferase (GST), and malondialdehyde (MDA)). No mortality was observed over 48 h. Concentration- and time-dependent immobilization was observed for both ARVs only at 250–1000 µg/L after 48 h, with significant immobilization observed for EFV compared to TFV. Results for biochemical responses demonstrated that both ARVs induced significant changes in CAT and GST activities, and MDA levels, with effects higher for EFV compared to TFV. Biochemical responses were indicative of oxidative stress alterations. Hence, both ARVs could potentially be toxic to D. magna.

A Review of the Presence of SARS-CoV-2 in Wastewater: Transmission Risks in Mexico

The appearance of SARS-CoV-2 represented a new health threat to humanity and affected millions of people; the transmission of this virus occurs through different routes, and one of them recently under debate in the international community is its possible incorporation and spread by sewage. Therefore, the present work's research objectives are to review the presence of SARS-CoV-2 in wastewater throughout the world and to analyze the coverage of wastewater treatment in Mexico to determine if there is a correlation between the positive cases of COVID-19 and the percentages of treated wastewater in Mexico as well as to investigate the evidence of possible transmission by aerosol sand untreated wastewater. Methodologically, a quick search of scientific literature was performed to identify evidence the presence of SARS-CoV-2 RNA (ribonucleic acid) in wastewater in four international databases. The statistical information of the positive cases of COVID-19 was obtained from data from the Health Secretary of the Mexican Government and the Johns Hopkins Coronavirus Resource Center. The information from the wastewater treatment plants in Mexico was obtained from official information of the National Water Commission of Mexico. The results showed sufficient evidence that SARS-CoV-2 remains alive in municipal wastewater in Mexico. Our analysis indicates that there is a low but significant correlation between the percentage of treated water and positive cases of coronavirus r = -0.385, with IC (95%) = (-0.647, -0.042) and p = 0.030; this result should be taken with caution because wastewater is not a transmission mechanism, but this finding is useful to highlight the need to increase the percentage of treated wastewater and to do it efficiently. In conclusions, the virus is present in untreated wastewater, and the early detection of SAR-CoV-2 could serve as a bioindicator method of the presence of the virus. This could be of great help to establish surveillance measures by zones to take preventive actions, which to date have not been considered by the Mexican health authorities. Unfortunately, wastewater treatment systems in Mexico are very fragile, and coverage is limited to urban areas and non-existent in rural areas. Furthermore, although the probability of contagion is relatively low, it can be a risk for wastewater treatment plant workers and people who are close to them.

Suspect screening of wastewaters to trace anti-COVID-19 drugs: Potential adverse effects on aquatic environment

During the first period of the SARS-CoV-2 pandemic, the lack of specific therapeutic treatments led to the provisional use of a number of drugs, with a continuous review of health protocols when new scientific evidence emerged. The management of this emergency sanitary situation could not take care of the possible indirect adverse effects on the environment, such as the release of a large amount of pharmaceuticals from wastewater treatment plants. The massive use of drugs, which were never used so widely until then, implied new risks for the aquatic environment. In this study, a suspect screening approach using Liquid Chromatography-High Resolution Mass Spectrometry techniques, allowed us to survey the presence of pharmaceuticals used for COVID-19 treatment in three WWTPs of Lombardy region, where the first European cluster of SARS-CoV-2 cases was detected. Starting from a list of sixty-three suspect compounds used against COVID-19 (including some metabolites and transformation products), six compounds were fully identified and monitored together with other target analytes, mainly pharmaceuticals of common use. A monthly monitoring campaign was conducted in a WWTP from April to December 2020 and the temporal trends of some anti-COVID-19 drugs were positively correlated with those of COVID-19 cases and deaths. The comparison of the average emission loads among the three WWTPs evidenced that the highest loads of hydroxychloroquine, azithromycin and ciprofloxacin were measured in the WWTP which received the sewages from a hospital specializing in the treatment of COVID-19 patients. The monitoring of the receiving water bodies evidenced the presence of eight compounds of high ecological concern, whose risk was assessed in terms of toxicity and the possibility of inducing antibiotic and viral resistance. The results clearly showed that the enhanced, but not completely justified, use of ciprofloxacin and azithromycin represented a risk for antibiotic resistance in the aquatic ecosystems.

Synthesis of flower-like MoS2/CNTs nanocomposite as an efficient catalyst for the sonocatalytic degradation of hydroxychloroquine

Contamination of water resources by pharmaceutical residues, especially during the time of pandemics, has become a serious problem worldwide and concerns have been raised about the efficient elimination of these compounds from aquatic environments. This study has focused on the development and evaluation of the sonocatalytic activity of a flower-like MoS₂/CNTs nanocomposite for the targeted degradation of hydroxychloroquine (HCQ). This nanocomposite was prepared using a facile hydrothermal route and characterized with various analytical methods, including X-ray diffraction and electron microscopy, which results confirmed the successful synthesis of the nanocomposite. Moreover, the results of the Brunauer-Emmett-Teller and diffuse reflectance spectroscopy analyses showed an increase in the specific surface area and a decrease in the band gap energy of the nanocomposite when compared with those of MoS₂. Nanocomposites with different component mass ratios were then synthesized, and MoS₂/CNTs (10:1) was identified to have the best sonocatalytic activity. The results indicated that 70% of HCQ with the initial concentration of 20 mg/L could be degraded using 0.1 g/L of MoS₂/CNTs (10:1) nanocomposite within 120 min of sonocatalysis at the pH of 8.7 (natural pH of the HCQ solution). The dominant reactive species in the sonocatalytic degradation process were identified using various scavengers and the intermediates generated during the process were detected using GC-MS analysis, enabling the development of a likely degradation scheme. In addition, the results of consecutive sonocatalytic cycles confirmed the stability and reusability of this nanocomposite for sonocatalytic applications. Thus, our data introduce MoS₂/CNTs nanocomposite as a proficient sonocatalyst for the treatment of pharmaceutical contaminants.

Pharmaceutical Pollution in Aquatic Environments: A Concise Review of Environmental Impacts and Bioremediation Systems

The presence of emerging contaminants in the environment, such as pharmaceuticals, is a growing global concern. The excessive use of medication globally, together with the recalcitrance of pharmaceuticals in traditional wastewater treatment systems, has caused these compounds to present a severe environmental problem. In recent years, the increase in their availability, access and use of drugs has caused concentrations in water bodies to rise substantially. Considered as emerging contaminants, pharmaceuticals represent a challenge in the field of environmental remediation; therefore, alternative add-on systems for traditional wastewater treatment plants are continuously being developed to mitigate their impact and reduce their effects on the environment and human health. In this review, we describe the current status and impact of pharmaceutical compounds as emerging contaminants, focusing on their presence in water bodies, and analyzing the development of bioremediation systems, especially mycoremediation, for the removal of these pharmaceutical compounds with a special focus on fungal technologies.

Detoxifying SARS-CoV-2 antiviral drugs from model and real wastewaters by industrial waste-derived multiphase photocatalysts

The use of antiviral drugs has surged as a result of the COVID-19 pandemic, resulting in higher concentrations of these pharmaceuticals in wastewater. The degradation efficiency of antiviral drugs in wastewater treatment plants has been reported to be too low due to their hydrophilic nature, and an additional procedure is usually necessary to degrade them completely. Photocatalysis is regarded as one of the most effective processes to degrade antiviral drugs. The present study aims at synthesizing multiphase photocatalysts by a simple calcination of industrial waste from ammonium molybdate production (WU photocatalysts) and its combination with WO₃ (WW photocatalysts). The X-ray diffraction (XRD) results confirm that the presence of multiple crystalline phases in the synthesized photocatalysts. UV-Vis diffuse reflectance spectra reveal that the synthesized multiphase photocatalysts absorb visible light up to 620 nm. Effects of calcination temperature of industrial waste (550-950 °C) and WO₃ content (0-100%) on photocatalytic activity of multiphase photocatalysts (WU and WW) for efficient removal of SARS-CoV-2 antiviral drugs (lopinavir and ritonavir) in model and real wastewaters are studied. The highest k₁ value is observed for the photocatalytic removal of ritonavir from model wastewater using WW4 (35.64 ×10^-2 min^-1). The multiphase photocatalysts exhibit 95% efficiency in the photocatalytic removal of ritonavir within 15 of visible light irradiation. In contrast, 60 min of visible light irradiation is necessary to achieve 95% efficiency in the photocatalytic removal of lopinavir. The ecotoxicity test using zebrafish (Danio rerio) embryos shows no toxicity for photocatalytically treated ritonavir-containing wastewater, and the contrary trend is observed for photocatalytically treated lopinavir-containing wastewater. The synthesized multiphase photocatalysts can be tested and applied for efficient degradation of other SARS-CoV-2 antiviral drugs in wastewater in the future.

Amplifying anti-flooding electrode to fabricate modular electro-fenton system for degradation of antiviral drug lamivudine in wastewater

The advanced oxidation based on in-situ hydrogen peroxide production using carbon air cathode is very potential for wastewater treatment. However, catalyst flooding and complex assembly patterns are the bottleneck limiting the air cathode to the long-term and large-scale application. In this work, a novel anti-flooding air-breathing cathode (ABC) was prepared by a simple rolling-spraying method with relatively low price commercial materials. The novel method changed the morphology of gas diffusion layer as well as adjusted the hydrophobicity of air side of the catalyst layer. As a result, water-air distribution management was achieved and TPI disequilibrium was prevented. Compare with traditional ABC, the H₂O₂ yield and current efficiency (CE) of optimized anti-flooding ABC (ABC_0.9) increased by 13.5% (941 ± 10 mg·L^-1·h^-1 with CE of 84% at 30 mA·cm^-2), the material cost and fabrication time decreased by 10.1% (2.32 ¥·dm^-2, ~0.36 $·dm^-2) and 40%. Amplified ABC coupled with Ti/IrO₂ anodes were integrated into a modular electrode used for H₂O₂generation. When the current density (j) increased from 10 to 30 mA·cm^-2, the energy cost increased from 0.19 to 0.43 ¥·mol^-1 H₂O₂ (from 0.03 to 0.07 $·mol^-1 H₂O₂). The modular electrode was utilized in a 2 L pre-pilot scale reactor for antiviral drug lamivudine degradation by electro-Fenton (EF) process. 100% of lamivudine and 78.1% of total organic carbon (TOC) were removed within 60 min at 20 mA·cm^-2. The susceptible sites on the lamivudine toward hydroxyl radicals were investigated and transformation products (TP) as well as degradation pathway were studied.

Unravelling multiple removal pathways of oseltamivir in wastewater by microalgae through experimentation and computation

Increased worldwide consumption of antiviral drugs (AVDs) amid COVID-19 has induced enormous burdens to the existing wastewater treatment systems. Microalgae-based bioremediation is a competitive alternative technology due to its simultaneous nutrient recovery and sustainable biomass production. However, knowledge about the fate, distribution, and interaction of AVDs with microalgae is yet to be determined. In this study, a concentration-determined influence of AVD oseltamivir (OT) was observed on the biochemical pathway of Chlorella sorkiniana (C.S-N1) in synthetic municipal wastewater. The results showed that high OT concentration inhibited biomass growth through increased oxidative stress and restrained photosynthesis. Nevertheless, complete OT removal was achieved at its optimized concentration of 10 mg/L by various biotic (82%) and abiotic processes (18.0%). The chemical alterations in three subtypes of extracellular polymeric substances (EPS) were primarily investigated by electrostatic (OT +8.22 mV vs. C.S-N1 -18.31 mV) and hydrophobic interactions between EPS-OT complexes supported by secondary structure protein analysis. Besides, six biodegradation-catalyzed transformation products were identified by quadrupole-time-of-flight mass spectrometer and by density functional theory. Moreover, all the TPs exhibited log Kow ≤ 5 and bioconcentration factor values of < 5000 L/kg, meeting the practical demands of environmental sustainability. This study broadens our understanding of microalgal bioadsorption and biodegradation, promoting microalgae bioremediation for nutrient recovery and AVDs removal.

Occurrence, detection and ecotoxicity studies of selected pharmaceuticals in aqueous ecosystems- a systematic appraisal

Pharmaceutical compounds (PCs) have globally emerged as a significant group of environmental contaminants due to the constant detection of their residues in the environment. The main scope of this review is to fill the void of information on the knowledge on the African occurrence of selected PCs in environmental matrices in comparison with those outside Africa and their respective toxic actions on both aquatic and non-aquatic biota through ecotoxicity bioassays. To achieve this objective, the study focused on commonly used and detected pharmaceutical drugs (residues). Based on the conducted literature survey, Africa has the highest levels of ciprofloxacin, sulfamethoxazole, lamivudine, acetaminophen, and diclofenac while Europe has the lowest of all these PC residues in her physical environments. For ecotoxicity bioassays, the few data available are mostly on individual groups of pharmaceuticals whereas there is sparsely available data on their combined forms.

Monsoon dilutes the concurrence but increases the correlation of viruses and Pharmaceuticals and Personal Care Products (PPCPs) in the urban waters of Guwahati, India: The context of pandemic viruses

Concurrence of pharmaceuticals and personal care products (PPCPs), pathogenic viruses, metals and microbial pollution along with their seasonal variations in the water environment are overarching in the context of existing pandemic, especially for tropical countries. The present study focuses on the seasonal influence on the vulnerability of urban water in Guwahati, the largest city in North-eastern India, through examining the concurrence of seven PPCPs, five viruses, faecal bacteria and nine metals in surface waters during monsoon (Summer-July 2017) and pre-monsoon (Winter-March 2018). Surface water sampling was carried out at different locations of the Brahmaputra River, its tributary Bharalu River (an unlined urban drain), and Dipor Bill Lake (Ramsar-recognized wetland). Both PPCPs and viruses were at high concentrations (e.g. up to 970 ng L^-1 caffeine, 2.5 × 10³ copies mL^-1 pepper mild mottle virus (PMMoV)) at the confluence points of urban drains and the river, while they were mostly undetectable at both upstream and downstream locations, implying strong self-purification ability of the river. All the analysed PPCPs and viruses were at much higher concentrations during pre-monsoon i.e., winter than during monsoon, implying heavy dilution and temperature effect during the monsoon. Overall, PPCPs and viruses were more correlated in monsoon but the risk quotient in the urban tributary was higher in pre-monsoon (e.g. 5061 in pre-monsoon and 1515 in monsoon for caffeine). PMMoV was found to be an excellent faecal pollution indicator due to its prevalence, detectability and specificity in all seasons. Overall, the seasonal fluctuations of the non-enveloped viruses monitored in this study is likely to be relevant for SARS-CoV-2. We contribute to address the literature scarcity pertaining to seasonal variations in the prevalence of viruses and their concurrences with contaminants of emerging concern.

Environmental and human health risk assessment of mixture of Covid-19 treating pharmaceutical drugs in environmental waters

This study identified ecological and human health risks exposure of COVID-19 pharmaceuticals and their metabolites in environmental waters. Environmental concentrations in aquatic species were predicted using surface water concentrations of pharmaceutical compounds. Predicted No-Effect Concentrations (PNEC) in aquatic organisms (green algae, daphnia, and fish) was estimated using EC50/LC50 values of pharmaceutical compounds taken from USEPA ECOSAR database. PNEC for human health risks was calculated using the acceptable daily intake values of drugs. Ecological PNEC revealed comparatively high values in algae (Chronic toxicity PNEC values, high to low: ribavirin (2.65 × 105 μg/L) to ritonavir (2.3 × 10-1 μg/L)) than daphnia and fish. Risk quotient (RQ) analysis revealed that algae (Avg. = 2.81 × 104) appeared to be the most sensitive species to pharmaceutical drugs followed by daphnia (Avg.: 1.28 × 104) and fish (Avg.: 1.028 × 103). Amongst the COVID-19 metabolites, lopinavir metabolites posed major risk to aquatic species. Ritonavir (RQ = 6.55) is the major drug responsible for human health risk through consumption of food (in the form fish) grown in pharmaceutically contaminated waters. Mixture toxicity analysis of drugs revealed that algae are the most vulnerable species amongst the three trophic levels. Maximum allowable concentration level for mixture of pharmaceuticals was found to be 0.53 mg/L.

Impacts of COVID-19 pandemic on the aquatic environment associated with disinfection byproducts and pharmaceuticals

In this study, concentrations of disinfection byproducts (DBPs) and COVID-19 related pharmaceuticals in wastewater effluents and surface water were measured two weeks, three months and eight months after the lockdown in Wuhan. Little temporal variation in DBP concentrations suggested intensified disinfection during the COVID-19 pandemic had limited impacts on the occurrence of DBPs in the aquatic environment. In contrast, the pandemic led to a significant increase in concentrations of lopinavir and ritonavir in wastewater effluents and surface water. The high detection frequency of these pharmaceuticals in surface water after the lockdown highlighted their mobility and persistence in the aquatic environment. The initial ecological risk assessment indicated moderate risks associated with these pharmaceuticals in surface water. As the global situation is still rapidly evolving with a continuous surge in the number of confirmed COVID-19 cases, our results suggest a pressing need for monitoring COVID-19 related pharmaceuticals as well as a systematic evaluation of their ecotoxicities in the aquatic environment.

A comprehensive review on preparation, functionalization and recent applications of nanofiber membranes in wastewater treatment

The direct discharge of significant amounts of polluted water into water bodies causes adverse ecological and human health effects. This severe deterioration in water quality creates significant challenges to meet the growing demand for clean water. Therefore, the world urgently needs environmentally friendly advanced technology to overcome this global crisis. In this regard, nanofiber-based membrane filtration is a promising technique in wastewater remediation because of their huge surface area, extremely porous structure, amenable pore size/pore size distribution, variety of material choices, and flexibility to modification with other functional materials. However, despite their unique properties, fouling, poor mechanical properties, shrinkage, and deformation are major drawbacks of nanofiber membranes for treating wastewater. This review presents a comprehensive overview of nanofiber membranes' fabrication and function in water purification applications as well as providing novel approaches to overcoming/alleviating the mentioned disadvantages. The review first presents nanofiber membrane preparation methods, focusing on electrospinning as a versatile and viable technique alongside discussing the parameters controlling nanofiber morphology. Afterward, the functionalization of nanofiber membranes by combining them with other nanomaterials, such as metal and metal-oxide nanoparticles, carbon nanotubes, metal-organic frameworks, and biomolecules, were demonstrated and discussed. In addition, nanofiber membranes functionalized with microorganisms were highlighted. Finally, we introduced and discussed in detail the most relevant and recent advances in nanofiber applications in wastewater treatment in the context of removing different pollutants (e.g., heavy metals, nutrients, radioactive elements, pharmaceuticals, and personal care products, dyes, and pesticides). Moreover, the promising antimicrobial ability of nanofiber membranes in removing microorganisms from wastewater has been fully underscored. We believe this comprehensive review could provide researchers with preliminary data and guide both researchers and producers engaged in the nanofiber membrane industry, letting them focus on the research gaps in wastewater treatment.

Identification of micropollutants from graywater of different complexity and remediation using multilayered membranes

Graywater reuse is one of the important concepts in attaining water sustainability. A major challenge in this area is to realize various components present in graywater. The present study involves the identification of the chemical components of graywater collected from three different environments and to investigate the efficiency of removal of some of these chemical components using ultrafiltration membranes (polyelectrolyte multilayer (PEM) membranes). The chemical components were analyzed using liquid chromatography connected with quadrupole time-of-flight (UPLC-Q-ToF-MS). A number of micropollutants including surfactants and certain contaminants of emerging concern (CECs) were identified from these samples. Out of 16 compounds identified, 13 were surfactants and the remaining were caffeine, oxybenzone, and benzophenone. These surfactants are mostly the ingredients of various detergents. Low-pressure filtration studies of the collected samples were carried out utilizing chitosan/polyacrylic acid (CHI/PAA) multilayer membranes. A 5.5 bilayer membrane showed more than 95% rejection of the identified compounds in the selected samples and significant improvement in the water quality parameters. This demonstrates that the membrane used in this work is effective in the removal of various chemicals from graywater as well as enhancing the water quality.

Ultra-high pressure liquid chromatography coupled to travelling wave ion mobility-time of flight mass spectrometry for the screening of pharmaceutical metabolites in wastewater samples: Application to antiretrovirals

The presence of pharmaceutical compounds in the aquatic environment is a significant environmental health concern, which is exacerbated by recent evidence of the contribution of drug metabolites to the overall pharmaceutical load. In light of a recent report of the occurrence of metabolites of antiretroviral drugs (ARVDs) in wastewater, we investigate in the present work the occurrence of further ARVD metabolites in samples obtained from a domestic wastewater treatment plant in the Western Cape, South Africa. Pharmacokinetic data indicate that ARVDs are biotransformed into several positional isomeric metabolites, only two of which have been reported wastewater samples. Given the challenges associated with the separation and identification of isomeric species in complex wastewater samples, a method based on liquid chromatography hyphenated to ion mobility spectrometry-high resolution mass spectrometry (LC-IMS-HR-MS) was implemented. Gradient LC separation was achieved on a sub-2 µm reversed phase column, while the quadrupole-time-of-flight MS was operated in data independent acquisition (DIA) mode to increase spectral coverage of detected features. A mass defect filter (MDF) template was implemented to detect ARVD metabolites with known phase I and phase II mass shifts and fractional mass differences and to filter out potential interferents. IMS proved particularly useful in filtering the MS data for co-eluting species according to arrival time to provide cleaner mass spectra. This approach allowed us to confirm the presence of two known hydroxylated efavirenz and nevirapine metabolites using authentic standards, and to tentatively identify a carboxylate metabolite of abacavir previously reported in literature. Furthermore, three hydroxylated-, two sulphated and one glucuronidated metabolite of efavirenz, two hydroxylated metabolites of nevirapine and one hydroxylated metabolite of ritonavir were tentatively or putatively identified in wastewater samples for the first time. Assignment of the metabolites is discussed in terms of high resolution fragmentation data, while collisional cross section (CCS) values measured for the detected analytes are reported to facilitate further work in this area.

Drug pollution & Sustainable Development Goals

The United Nations set "The 2030 Agenda for Sustainable Development," which includes the Sustainable Development Goals (SDGs), a collection of 17 global goals designed to be a "blueprint to achieve a better and more sustainable future for all". Although only mentioned in one of the seventeen goals (goal 3), we argue that drugs in general, and growing drug pollution in particular, affects the SDGs in deeper, not readily apparent ways. So far, the emerging problem of drug pollution has not been sufficiently addressed. Here, we outline and discuss how drug pollution can affect SDGs and even threaten their achievement.

Occurrence and Effects of Antimicrobials Drugs in Aquatic Ecosystems

Currently, thanks to the development of sensitive analytical techniques, the presence of different emerging pollutants in aquatic ecosystems has been evidenced; however, most of them have not been submitted to any regulation so far. Among emerging contaminants, antimicrobials have received particular attention in recent decades, mainly due to the concerning development of antibiotic resistance observed in bacteria, but little is known about the toxicological and ecological impact that antimicrobials can have on aquatic ecosystems. Their high consumption in human and veterinary medicine, food-producing animals and aquaculture, as well as persistence and poor absorption have caused antimicrobials to be discharged into receiving waters, with or without prior treatment, where they have been detected at ng-mg L−1 levels with the potential to cause effects on the various organisms living within aquatic systems. This review presents the current knowledge on the occurrence of antimicrobials in aquatic ecosystems, emphasizing their occurrence in different environmental matrixes and the effects on aquatic organisms (cyanobacteria, microalgae, invertebrates and vertebrates).

Aquatic concentration and risk assessment of pharmaceutically active compounds in the environment

Pharmaceutically active compounds are increasingly detected in raw and treated wastewater, surface water, and drinking water worldwide. These compounds can cause adverse effects to the ecosystem even at low concentrations and, to assess these impacts, toxicity tests are essential. However, the toxicity data are scarce for many PhACs, and when available, they are dispersed in the literature. The values of pharmaceuticals concentration in the environment and toxicity data are essential for measuring their environmental and human health risks. Thus this review verified the concentrations of pharmaceuticals in the aquatic environment and the toxicity related to them. The risk assessment was also carried out. Diclofenac, naproxen, erythromycin, roxithromycin, and 17β-estradiol presented a high environment risk and 17α-ethinylestradiol presented a high human health risk. This shows the potential of these pharmaceuticals to cause adverse effects to the ecosystem and humans and establishes the necessity of their removal through advanced technologies.

Membrane bioreactors for hospital wastewater treatment: recent advancements in membranes and processes

Discharged hospital wastewater contains various pathogenic microorganisms, antibiotic groups, toxic organic compounds, radioactive elements, and ionic pollutants. These contaminants harm the environment and human health causing the spread of disease. Thus, effective treatment of hospital wastewater is an urgent task for sustainable development. Membranes, with controllable porous and nonporous structures, have been rapidly developed for molecular separations. In particular, membrane bioreactor (MBR) technology demonstrated high removal efficiency toward organic compounds and low waste sludge production. To further enhance the separation efficiency and achieve material recovery from hospital waste streams, novel concepts of MBRs and their applications are rapidly evolved through hybridizing novel membranes (non hydrophilic ultrafiltration/microfiltration) into the MBR units (hybrid MBRs) or the MBR as a pretreatment step and integrating other membrane processes as subsequent secondary purification step (integrated MBR-membrane systems). However, there is a lack of reviews on the latest advancement in MBR technologies for hospital wastewater treatment, and analysis on its major challenges and future trends. This review started with an overview of main pollutants in common hospital waste-water, followed by an understanding on the key performance indicators/criteria in MBR membranes (i.e., solute selectivity) and processes (e.g., fouling). Then, an in-depth analysis was provided into the recent development of hybrid MBR and integrated MBR-membrane system concepts, and applications correlated with wastewater sources, with a particular focus on hospital wastewaters. It is anticipated that this review will shed light on the knowledge gaps in the field, highlighting the potential contribution of hybrid MBRs and integrated MBR-membrane systems toward global epidemic prevention.

Development and validation of sensitive methods for simultaneous determination of 9 antiviral drugs in different various environmental matrices by UPLC-MS/MS

Trace antiviral drug contamination in aquatic ecosystems is becoming a significant environmental concern that requires an urgent efficient determination method. Here we developed sensitive and robust multi-residue determination methods to simultaneously extract and analyze 9 commonly used antiviral drugs (abacavir, zidovudine, efavirenz, nevirapine, ritonavir, lopinavir, lamivudine, telbivudine and entecavir) in surface water, wastewater, sediment, and sludge. Water samples were extracted with solid-phase extraction (SPE) technique using tandem hydrophilic-lipophilic balance and graphitized carbon black cartridges, while sediment and sludge samples were extracted using QuEChERS (quick, easy, cheap, effective, rugged, and safe) method. The extraction conditions of SPE (pH and cartridge type) and QuEChERS (acetic acid content, salts reagent, and purification sorbent) methods were carefully optimized. We observed that under optimum conditions, the method quantification limits of the 9 antiviral drugs in water and solid samples ranged from 0.05 to 19.23 ng L^-1 and from 0.02 to 7.38 ng g^-1, respectively. For environmental samples spiking 3 different concentrations, the recovery values for the most targeted antiviral drugs ranged from 70 to 130%, except for efavirenz. All targeted antiviral drugs were detected in wastewater samples except for entecavir. We also found abacavir, efavirenz, ritonavir, lopinavir, and telbivudine in sediment and sludge samples. Notably, telbivudine was identified in all environmental matrices, with a high concentration of 127 ng L^-1 and 222 ng g^-1 in water and sediment samples, respectively.

Transformation of antiviral ribavirin during ozone/PMS intensified disinfection amid COVID-19 pandemic

Due to the spread of coronavirus disease 2019 (COVID-19), large amounts of antivirals were consumed and released into wastewater, posing risks to the ecosystem and human health. Ozonation is commonly utilized as pre-oxidation process to enhance the disinfection of hospital wastewater during COVID-19 spread. In this study, the transformation of ribavirin, antiviral for COVID-19, during ozone/PMS‑chlorine intensified disinfection process was investigated. •OH followed by O₃ accounted for the dominant ribavirin degradation in most conditions due to higher reaction rate constant between ribavirin and •OH vs. SO₄•^- (1.9 × 10⁹ vs. 7.9 × 10⁷ M^-1 s^-1, respectively). During the O₃/PMS process, ribavirin was dehydrogenated at the hydroxyl groups first, then lost the amide or the methanol group. Chloride at low concentrations (e.g., 0.5- 2 mg/L) slightly accelerated ribavirin degradation, while bromide, iodide, bicarbonate, and dissolved organic matter all reduced the degradation efficiency. In the presence of bromide, O₃/PMS process resulted in the formation of organic brominated oxidation by-products (OBPs), the concentration of which increased with increasing bromide dosage. However, the formation of halogenated OBPs was negligible when chloride or iodide existed. Compared to the O₃/H₂O₂ process, the concentration of brominated OBPs was significantly higher after ozonation or the O₃/PMS process. This study suggests that the potential risks of the organic brominated OBPs should be taken into consideration when ozonation and ozone-based processes are used to enhance disinfection in the presence of bromide amid COVID-19 pandemic.

Algae-mediated processes for the treatment of antiretroviral drugs in wastewater: Prospects and challenges

The prevalence of pharmaceuticals (PCs), especially antiretroviral (ARV) drugs in various aquatic ecosystems has been expansively reported, wherein wastewater treatment plants (WWTPs) are identified as the primary point source. Consequently, the occurrence, ecotoxicity and treatment of ARV drugs in WWTPs have drawn much attention in recent years. Numerous studies have shown that the widely employed activated sludge-based WWTPs are incapable of removing ARV drugs efficiently from wastewater. Recently, algae-based wastewater treatment processes have shown promising results in PCs removal from wastewater, either completely or partially, through different processes such as biosorption, bioaccumulation, and intra-/inter-cellular degradation. Algal species have also shown to tolerate high concentrations of ARV drugs than the reported concentrations in the environmental matrices. In this review, emphasis has been given on discussing the current status of the occurrence of ARV drugs in the aquatic environment and WWTPs. Besides, the current trends and future perspectives of PCs removal by algae are critically reviewed and discussed. The potential pathways and mechanisms of ARV drugs removal by algae have also been discussed.

Chronic toxicity and environmental risk assessment of antivirals in Ceriodaphnia dubia and Raphidocelis subcapitata

Antiviral drugs are a class of medications used for treating viral infections. Due to their widespread use, especially in cases of pandemics and limited human metabolism, antivirals have been detected in multiple environmental matrices. This study aims to evaluate the chronic effects of acyclovir, efavirenz, lamivudine and zidovudine using Ceriodaphnia dubia and Raphidocelis subcapitata. The results with R. subcapitata showed the following toxicities: zidovudine (IC₅₀ = 5.442 mg L^-1) < acyclovir (IC₅₀ = 3.612 mg L^-1) < lamivudine (IC₅₀ = 3.013 mg L^-1) < efavirenz (IC₅₀ = 0.034 mg L^-1). The results of the chronic bioassay with C. dubia demonstrated that zidovudine is the least toxic (EC₅₀ = 5.671 mg L^-1), followed by acyclovir (EC₅₀ = 3.062 mg L^-1), lamivudine (EC₅₀ = 1.345 mg L^-1) and efavirenz (EC₅₀ = 0.026 mg L^-1). Both species have been shown to be sensitive to efavirenz. A risk quotient (RQ) was calculated, and efavirenz had an RQ greater than 1 for both species, and lamivudine had an RQ greater than 1 for C. dubia, representing a high ecological risk for these organisms. Antivirals pose a significant environmental risk to aquatic organisms and should be taken into consideration in future monitoring of water sources.

Predicting the trend and utility of different photocatalysts for degradation of pharmaceutically active compounds: A special emphasis on photocatalytic materials, modifications, and performance comparison

The rapid rise in the healthcare sector has led to an increase in pharmaceutically active compounds (PhACs) in different aqueous bodies. The toxicity of the PhACs and their ability to persist after conventional treatment processes have escalated research in the field of photocatalytic treatment. Although different photocatalysts have been successful in degrading PhACs, their inherent drawbacks have severely limited their application on a large scale. A substantial amount of research has been aimed at overcoming the high cost of the photocatalytic material, low quantum yield, the formation of toxic end products, etc. Hence, to further research in this field, researchers must have a fair idea of the current trends in the application of different photocatalysts. In this article, the trends in the use of various photocatalysts for the removal of different PhACs have been circumscribed. The performance of different groups of photocatalysts to degrade PhACs from synthetic and real wastewater has been addressed. The drawbacks and advantages of these materials have been compared, and their future in the field of PhACs removal has been predicted using S-curve analysis. Zinc and titanium-based photocatalysts were efficient under UV irradiation, while bismuth and graphene-based materials exhibited exemplary performance in visible light. However, iron-based compounds were found to have the most promising future, which may be because of their magnetic properties, easy availability, low bandgap, etc. Different modification techniques, such as morphology modification, doping, heterojunction formation, etc., have also been discussed. This study may help researchers to clarify the current research status in the field of photocatalytic treatment of PhACs and provide valuable information for future research.

Specific phenotypic, genomic, and fitness evolutionary trajectories toward streptomycin resistance induced by pesticide co-stressors in Escherichia coli

To explore how co-occurring non-antibiotic environmental stressors affect evolutionary trajectories toward antibiotic resistance, we exposed susceptible Escherichia coli K-12 populations to environmentally relevant levels of pesticides and streptomycin for 500 generations. The coexposure substantially changed the phenotypic, genotypic, and fitness evolutionary trajectories, resulting in much stronger streptomycin resistance (>15-fold increase) of the populations. Antibiotic target modification mutations in rpsL and rsmG, which emerged and dominated at late stages of evolution, conferred the strong resistance even with less than 1% abundance, while the off-target mutations in nuoG, nuoL, glnE, and yaiW dominated at early stages only led to mild resistance (2.5-6-fold increase). Moreover, the strongly resistant mutants exhibited lower fitness costs even without the selective pressure and had lower minimal selection concentrations than the mildly resistant ones. Removal of the selective pressure did not reverse the strong resistance of coexposed populations at a later evolutionary stage. The findings suggest higher risks of the selection and propagation of strong antibiotic resistance in environments potentially impacted by antibiotics and pesticides.

Environmental Risk Characterization of an Antiretroviral (ARV) Lamivudine in Ecosystems

Antiretroviral drugs for the treatment of human immunodeficiency virus (HIV) and other viral infections are among the emerging contaminants considered for ecological risk assessment. These compounds have been reported to be widely distributed in water bodies and other aquatic environments, while data concerning the risk they may pose to unintended non-target species in a different ecosystem (environment) is scanty. In South Africa and other developing countries, lamivudine is one of the common antiretrovirals applied. Despite this, little is known about its environmental impacts as an emerging contaminant. The present study employed a battery of ecotoxicity bioassays to assess the environmental threat lamivudine poses to aquatic fauna and flora. Daphnia magna (filter feeders), the Ames bacterial mutagenicity test, Lactuca sativa (lettuce) germination test, and the Allium cepa root tip assay were conducted, testing lamivudine at two concentrations (10 and 100 µg/L), with environmental relevance. The Daphnia magna toxicity test revealed a statistically significant response (p << 0.05) with a mortality rate of 85% on exposure to 100 µg/L lamivudine in freshwater, which increased to 100% at 48-h exposure. At lower concentrations of 10 µg/L lamivudine, 90% and 55% survival rates were observed at 24 h and 48 h, respectively. No potential mutagenic effects were observed from the Ames test at both concentrations of lamivudine. Allium cepa bioassays revealed a noticeable adverse impact on the root lengths on exposure to 100 µg/L lamivudine. This impact was further investigated through microscopic examination, revealing some chromosomal aberration in the exposed Allium cepa root tips. The Lactuca sativa bioassay showed a slight adverse impact on both the germination rate of the seeds and their respective hypocotyl lengths compared to the control. Overall, this indicates that lamivudine poses an ecological health risk at different trophic levels, to both flora and fauna, at concentrations previously found in the environment.

A critical review on environmental presence of pharmaceutical drugs tested for the covid-19 treatment

On March 11, 2020, the World Health Organization (WHO) declared COVID-19 a pandemic. The outbreak caused a worldwide impact, becoming a health threat to the general population and its professionals. To date, there are no specific antiviral treatments or vaccines for the COVID-19 infection, however, some drugs are being clinically tested. The use of these drugs on large scale raises great concern about their imminent environmental risk, since the elimination of these compounds by feces and urine associated with the inefficiency of sewage treatment plants in their removal can result in their persistence in the environment, putting in risk the health of humans and of other species. Thus, the goal of this work was to conduct a review of other studies that evaluated the presence of the drugs chloroquine, hydroxychloroquine, azithromycin, ivermectin, dexamethasone, remdesivir, favipiravir and some HIV antivirals in the environment. The research indicated the presence of these drugs in the environment in different regions, with concentration data that could serve as a basis for further comparative studies following the pandemic.

Environmental impact assessment of COVID-19 therapeutic solutions. A prospective analysis

Several medicinal products for human use are currently under consideration as potential treatment for COVID-19 pandemic. As proposals cover also prophylactic use, the treatment could be massive, resulting in unprecedent levels of antiviral emissions to the aquatic environment. We have adapted previous models and used available information for predicting the environmental impact of representative medicinal products, covering the main groups under consideration: multitarget antiparasitic (chloroquines and ivermectin), glucocorticoids, macrolide antibiotics and antiviral drugs including their pharmacokinetic boosters. The retrieved information has been sufficient for conducting a conventional environmental risk assessment for the group of miscellaneous medicines; results suggest low concern for the chloroquines and dexamethasone while very high impact for ivermectin and azithromycin, even at use levels well below the default value of 1% of the population. The information on the ecotoxicity of the antiviral medicines is very scarce, thus we have explored an innovative pharmacodynamic-based approach, combining read-across, quantitative structure-activity relationship (QSAR), US EPA's Toxicity Forecaster (ToxCast) in vitro data, pharmacological modes of action, and the observed adverse effects. The results highlight fish sublethal effects as the most sensitive target and identify possible concerns. These results offer guidance for minimizing the environmental risk of treatment medication for COVID-19.

Predicted occurrence, ecotoxicological risk and environmentally acquired resistance of antiviral drugs associated with COVID-19 in environmental waters

Antiviral drugs have been used to treat the ever-growing number of coronavirus disease, 2019 (COVID-19) patients. Consequently, unprecedented amounts of such drug residues discharging into ambient waters raise concerns on the potential ecotoxicological effects to aquatic lives, as well as development of antiviral drug-resistance in wildlife. Here, we estimated the occurrence, fate and ecotoxicological risk of 11 therapeutic agents suggested as drugs for COVID-19 treatment and their 13 metabolites in wastewater and environmental waters, based on drug consumption, physical-chemical property, and ecotoxicological and pharmacological data for the drugs, with the aid of quantitative structure-activity relationship (QSAR) modelling. Our results suggest that the removal efficiencies at conventional wastewater treatment plants will remain low (<20%) for half of the substances, and consequently, high drug residues (e.g. 7402 ng/L ribavirin, 4231 ng/L favipiravir, 730 ng/L lopinavir, 319 ng/L remdesivir; each combined for both unchanged forms and metabolites; and when each drug is administered to 100 patients out of 100,000 populations on a day) can be present in secondary effluents and persist in the environmental waters. Ecotoxicological risk in receiving river waters can be high (risk quotient >1) by a use of favipiravir, lopinavir, umifenovir and ritonavir, and medium (risk quotient >0.1) by a use of chloroquine, hydroxychloroquine, remdesivir, and ribavirin, while the risk will remain low (risk quotient <0.1) for dexamethasone and oseltamivir. The potential of wild animals acquiring antiviral drug resistance was estimated to be low. Our prediction suggests a pressing need for proper usage and waste management of antiviral drugs as well as for improving removal efficiencies of drug residues in wastewater.

Correlation of SARS-CoV-2 RNA in wastewater with COVID-19 disease burden in sewersheds

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease (COVID-19), is shed in feces and the viral ribonucleic acid (RNA) is detectable in wastewater. A nine-week wastewater epidemiology study of ten wastewater facilities, serving 39% of the state of Utah or 1.26 M individuals was conducted in April and May of 2020. COVID-19 cases were tabulated from within each sewershed boundary. RNA from SARS-CoV-2 was detectable in 61% of 126 wastewater samples. Urban sewersheds serving >100,000 individuals and tourist communities had higher detection frequencies. An outbreak of COVID-19 across two communities positively correlated with an increase in wastewater SARS-CoV-2 RNA, while a decline in COVID-19 cases preceded a decline in RNA. SARS-CoV-2 RNA followed a first order decay rate in wastewater, while 90% of the RNA was present in the liquid phase of the influent. Infiltration and inflow, virus decay and sewershed characteristics should be considered during correlation analysis of SAR-CoV-2 with COVID-19 cases. These results provide evidence of the utility of wastewater epidemiology to assist in public health responses to COVID-19.

Correlation of SARS-CoV-2 RNA in wastewater with COVID-19 disease burden in sewersheds

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the coronavirus disease (COVID-19), is shed in feces and the viral ribonucleic acid (RNA) is detectable in wastewater. A nine-week wastewater epidemiology study of ten wastewater facilities, serving 39% of the state of Utah or 1.26 M individuals was conducted in April and May of 2020. COVID-19 cases were tabulated from within each sewershed boundary. RNA from SARS-CoV-2 was detectable in 61% of 126 wastewater samples. Urban sewersheds serving >100,000 individuals and tourist communities had higher detection frequencies. An outbreak of COVID-19 across two communities positively correlated with an increase in wastewater SARS-CoV-2 RNA, while a decline in COVID-19 cases preceded a decline in RNA. SARS-CoV-2 RNA followed a first order decay rate in wastewater, while 90% of the RNA was present in the liquid phase of the influent. Infiltration and inflow, virus decay and sewershed characteristics should be considered during correlation analysis of SAR-CoV-2 with COVID-19 cases. These results provide evidence of the utility of wastewater epidemiology to assist in public health responses to COVID-19.

SARS-CoV-2 and other main pathogenic microorganisms in the environment: Situation in Galicia and Spain

In the context of the current COVID-19 pandemic, and mostly taking a broad perspective, it is clearly relevant to study environmental factors that could affect eventual future outbreaks due to coronaviruses and/or other pathogenic microorganisms. In view of that, the authors of this manuscript review the situation of SARS-CoV-2 and other main pathogenic microorganisms in the environment, focusing on Galicia and Spain. Overall, in addition to showing local data, it is put in evidence that, summed to all efforts being carried out to treat/control this and any other eventual future epidemic diseases, both at local and global levels, a deep attention should be paid to ecological/environmental aspects that have effects on the planet, its ecosystems and their relations/associations with the probability of spreading of eventual future pandemics.

Toxicological Study on Chiral Fluoxetine Exposure to Adult Zebrafish (Danio rerio): Enantioselective and Sexual Mechanism on Disruption of the Brain Serotonergic System

The increasing number of people with depression worldwide has led to concerns regarding antidepressant contamination in aquatic environments, which could have the risk of negative effects on aquatic organisms. Chirality increases its toxicity potentials. Accordingly, we investigated the negative effects of racemic (rac-), R-, and S-FX at environmental levels (100 ng/L) on the brain serotonergic system in zebrafish (Danio rerio) for 42 days. Additionally, we measured the whole-body concentrations of FX and norfluoxetine (NFX). We found that S-FX exposure disrupted the brain serotonergic system more severely than rac- and R-FX exposure. The mechanism underlying this disruption induced by S-FX was sex-specific, with female zebrafish showing disruption of the serotonin (5-HT) release process but male zebrafish showing disruption of the 5-HT synthesis process. In addition, enantioselective enrichment and biotransformation (R-FX to R-NFX and S-FX to S-NFX) occurred in zebrafish. Sex-specific accumulation was also observed, with higher concentrations in females. Our study provides evidence for enantiomer- and sex-specific effects of FX exposure at biologically relevant concentrations. More broadly, our study demonstrated that SSRI antidepressants, such as FX, can affect aquatic life by causing important shifts in not only their active sites of the serotonin transporter.

Ozonation products of zidovudine and thymidine in oxidative water treatment

Ozonation is an advanced treatment technology that is increasingly used for the removal of organic micropollutants from wastewater and drinking water. However, reaction of organic compounds with ozone can also result in the formation of toxic transformation products. In the present study, the degradation of the antiviral drug zidovudine during ozonation was investigated. To obtain further insights into the reaction mechanisms and pathways, results of zidovudine were compared with the transformation of the naturally occurring derivative thymidine. Kinetic experiments were accompanied by elucidation of formed transformation products using lab-scale batch experiments and subsequent liquid chromatography - high resolution mass spectrometry (LC-HRMS) analysis. Degradation rate constants for zidovudine with ozone in the presence of t-BuOH as radical scavenger varied between 2.8 ∙ 10⁴ M^-1 s^-1 (pH 7) and 3.2 ∙ 10⁴ M^-1 s^-1 (pH 3). The structural difference of zidovudine to thymidine is the exchange of the OH-moiety by the azide function at position 3'. In contrast to inorganic azide, no reaction with ozone was observed for the organic bound azide. In total, nine transformation products (TPs) were identified for both zidovudine and thymidine. Their formation can be attributed to the attack of ozone at the C-C-double bond of the pyrimidine-base. As a result of rearrangements, the primary ozonide decomposed in three pathways forming two different TPs, including hydroperoxide TPs. Rearrangement reactions followed by hydrolysis and subsequent release of H₂O₂ further revealed a cascade of TPs containing amide moieties. In addition, a formyl amide riboside and a urea riboside were identified as TPs indicating that oxidations of amide groups occur during ozonation processes.

Uptake, accumulation and impact of antiretroviral and antiviral pharmaceutical compounds in lettuce

While the contamination of agroecosystems with pharmaceutical compounds has been reported, the fate of these compounds, particularly uptake into plants remains unclear. This lack of environmental fate data is evident for a critical class of pharmaceuticals, the antivirals and antiretrovirals (ARVDs). Thus, this study evaluated the root uptake of the antiretroviral compounds nevirapine, lamivudine and efavirenz, and the antiviral compound oseltamivir in lettuce. The lettuce was hydroponically grown in a nutrient solution containing the four ARVD pharmaceutical mixture in the 1-100 μg L-1 concentration range. The measured bioaccumulation showed that efavirenz and lamivudine accumulated to the highest and lowest degree, at concentrations of 3463 ng g-1 and 691 ng g-1 respectively. The translocation factor between the root and leaf for nevirapine was greater than 1. The highest concentration of the pharmaceutical mixture had a physiological impact on the lettuce. Potential toxicity was evidenced by a statistically significant 34% (p = 0.04) mean reduction in root and leaf biomass in the 100 μg L-1 ARVD mix exposed lettuce, compared with the controls. This study advances knowledge of the fate of ARVDs in agroecosystems, in particular, plant root - ARVD interaction and the resulting potentially toxic effects on plants.

F-doped ZnO nano- and meso-crystals with enhanced photocatalytic activity in diclofenac degradation

Diclofenac (DCF), a non-steroidal anti-inflammatory drug, is considered one of the most widespread emerging contaminants. Its incidence in water can favor the growth of drug-resistant bacteria and harm aquatic organisms endangering both the human health and the ecosystem. Advanced oxidation processes (AOPs) based on the action of reactive oxygen species are very effective technologies for the removal of this contaminant from water. In this context, ZnO is one of the most studied semiconductors for photocatalytic water treatment. In this work, the photocatalytic activity of fluorine-doped ZnO nano- and meso-crystals synthesized by a hydrothermal approach is reported, exploring the role of a low F atomic concentration (0.25, 0.5 and 1 at. %) on the degradation of DCF in comparison with bare ZnO. All doped samples show high rates of DCF degradation and mineralization, which were realized primarily thanks to their high efficiency in the generation of hydroxyl radicals (OH). The property-structure-function relationships of the materials are investigated by complementary techniques, such as SEM, XRD, EPR, UV-vis DRS and PL, with the aim to evaluate the role of fluorine in determining their morphological, electronic and optical properties.

Application of multi-parameter population model based on endogenous population biomarkers and flow volume in wastewater epidemiology

The consumption or prevalence of acesulfame, caffeine, paracetamol and amantadine was estimated by wastewater-based epidemiology based on a multi-parameter population model in 20 sewage treatment plants (STPs) in Hebei province, China. To minimize the uncertainties contributed by population estimation in WBE, a multi-parameter population model was established based on the population biomarkers equivalent population and flow volume-population with the weight factors calculated by the analytic hierarchy process (AHP). 4-Pyridoxic acid (4-PA), cotinine, trans-3'-hydroxycotinine (trans-3'-OH-Cot) and 1,4-methylimidazole acetic acid (MIAA) were selected as population biomarkers. The estimated model population showed the highest correlations (r² = 0.97, p < 0.01) and lowest variation (one way-ANOVA, p = 0.82, mean variation: -0.1%) comparing to the census data, suggestion better population estimation. The estimated consumption of acesulfame, caffeine, paracetamol and amantadine was 6.7 ± 2.4 mg/day/inh, 50.5 ± 38.5 mg/day/inh, 61.5 ± 52.7 mg/day/inh and 0.52 ± 0.33 mg/day/inh, respectively. Meanwhile, the prevalence of paracetamol and amantadine was calculated to be 5.3% ± 4.5% and 0.28% ± 0.18%, respectively. The estimated results were consistent with that of previous researches in China and were also in accordance with the consumption calculated by sales data (acesulfame and paracetamol). Moreover, uncertainty study showed decrease in population-associated uncertainties by using a multi-parameter population model. The results demonstrated that the multi-parameter population model constructed in this research is feasible to apply in WBE and might lead to lower uncertainties in population estimation.

A chronicle of SARS-CoV-2: Seasonality, environmental fate, transport, inactivation, and antiviral drug resistance

In this review, we present the environmental perspectives of the viruses and antiviral drugs related to SARS-CoV-2. The present review paper discusses occurrence, fate, transport, susceptibility, and inactivation mechanisms of viruses in the environment as well as environmental occurrence and fate of antiviral drugs, and prospects (prevalence and occurrence) of antiviral drug resistance (both antiviral drug resistant viruses and antiviral resistance in the human). During winter, the number of viral disease cases and environmental occurrence of antiviral drug surge due to various biotic and abiotic factors such as transmission pathways, human behaviour, susceptibility, and immunity as well as cold climatic conditions. Adsorption and persistence critically determine the fate and transport of viruses in the environment. Inactivation and disinfection of virus include UV, alcohol, and other chemical-base methods but the susceptibility of virus against these methods varies. Wastewater treatment plants (WWTPs) are major reserviors of antiviral drugs and their metabolites and transformation products. Ecotoxicity of antiviral drug residues against aquatic organisms have been reported, however more threatening is the development of antiviral resistance, both in humans and in wild animal reservoirs. In particular, emergence of antiviral drug-resistant viruses via exposure of wild animals to high loads of antiviral residues during the current pandemic needs further evaluation.

Prospects and challenges of photocatalysis for degradation and mineralization of antiviral drugs

Among the outbreak of influenza and other pandemics such as SARS-CoV-2 recently over the globe, antiviral drugs were significantly concerned with controlling the disease and these pandemics. They have been developed for seven decades around more than 90 drugs categorized licensed to treat nine human infectious diseases. Based on their functional group, antiviral compounds will mitigate infectivity and symptoms and reduce the illness period by arresting the viral replication cycle at different stages. Antiviral drugs have been developed complexly and met many biothreat challenges due to their high biosafety level requirement. In recent years, the spreading of novel virus strains that are a threat to human life, the development in researching and manufacturing new types of antiviral drugs increases and the use by patients and clinicians have increased. Antiviral compounds have been reported only partly removed during wastewater treatment. They were available in wastewater treatment plant effluents and found in surface water from rivers and streams, underground water, and even in drinking water. Photocatalytic degradation of antiviral drugs was exploding to clear the environmental waters from the antiviral drugs. The principle of photocatalysis is based on the excitation of the catalyst material by irradiation of light. The catalyst produces free radicals under the action of photons, which will destroy the pollutants adsorbed on its surface. The photocatalytic degradation mechanism of antiviral drugs can be understood through decomposing in a heterogeneous photocatalytic system and which species are involved in the active decomposition of the drug and then photocatalytically degrading into intermediates or mineralization products. The intermediates and the reaction pathway of antiviral compound photocatalytic degradation are complicated. However, some of the degradation processes are complete, and inorganic compounds (CO₂ and H₂O) are their final products.