Acute effects of acetaminophen on the developmental, swimming performance and cardiovascular activities of the African catfish embryos/larvae (Clarias gariepinus)

Risk Assessment of Micropollutants for Human and Environmental Health: Alignment with the Urban Wastewater Treatment Directive in Southeastern Spain

The reuse of reclaimed water is essential for sustainable water management in arid regions. However, despite advancements in Wastewater Treatment Plants (WWTPs), certain micropollutants may persist. To address these challenges, the recently enacted European Urban Wastewater Treatment Directive (UWWTD) has established strict standards focused on monitoring twelve specific indicator compounds. In line with this, the present study aims to evaluate the concentrations and potential risks of these twelve UWWTD-designated compounds across various water sources, including surface water, groundwater, and effluents from a WWTP in the southeast of Spain. Although none of the evaluated water sources are, as expected, intended for human consumption, risks were assessed based on worst-case scenarios that could amplify their impact. The study assessed potential risks to human health across different age groups and ecosystems, focusing on key organisms such as fish, daphnia, and algae, using empirical assessment approaches. The risk assessment identified a low risk for most compounds regarding human health, except for citalopram (HRQ = 19.116) and irbesartan (HRQ = 1.104), which showed high human risk quotients (HQR > 1) in babies, particularly in reclaimed water. In terms of ecotoxicological risk, irbesartan presented the highest ecological risk quotient (ERQ = 3.500) in fish, followed by clarithromycin, with algae (ERQ = 1.500) being the most vulnerable organism. Furthermore, compounds like citalopram, venlafaxine, and benzotriazole exhibited moderate ecological risks (ERQ between 0.1 and 1) in the reclaimed water, and their risk was reduced in surface water and groundwater. Finally, this study discussed the potential impacts of elevated concentrations of these emerging compounds, emphasizing the need for rigorous wastewater monitoring to protect human health and ecosystem integrity. It also revealed notable differences in risk assessment outcomes when comparing two distinct evaluation approaches, further highlighting the complexities of accurately assessing these risks.

In situ synthesis of a UIO-66-NH2@Ti3C2 composite for advanced electrochemical detection of acetaminophen

Acetaminophen (AP) is a widely used analgesic and antipyretic drug, but its excessive use poses health risks and contributes to environmental contamination. In response to the need for rapid, accurate, and cost-effective detection methods, we developed a highly sensitive and selective electrochemical sensor for AP. The sensor was based on a composite of UIO-66-NH2 (UN) and an MXene (Ti3C2). UIO-66-NH2 was in situ synthesized onto the MXene via a one-step hydrothermal process with a varying MXene content, followed by calcination at 300 °C under an argon (Ar) flow. This treatment induced the formation of TiO2 on the MXene surface and increased the interlayer spacing, which enhanced its electrochemical performance. The resulting UN@Ti3C2-C electrode exhibited remarkable electrochemical activity due to the high surface area and excellent conductivity of the MXene. The fabricated sensor demonstrated a simple yet effective approach for the rapid and quantitative detection of AP, with a linear detection range of 0.032-160 μM and a low detection limit of 10 nM. Moreover, the sensor was successfully applied to detect AP in different water samples, validating its potential as a reliable and efficient tool for AP monitoring.

Suspect screening and quantitative analysis of 165 contaminants of emerging concern in water, sediments, and biota using LC-MS/MS: Ecotoxicological and human health risk assessment

This study aimed to implement a targeted multiple reaction monitoring (MRM) screening strategy using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) for the initial detection of 165 compounds of emerging concern (CECs) in water, sediment, and fish samples. Following the screening, confirmatory and quantitative analyses were conducted using analytical standards for the detected compounds. Qualitative results were confirmed using high-resolution mass spectrometry (HRMS) for those CECs without available standards. Ecotoxicological and human health risk assessments were performed for the quantified CECs. The analysis identified 35 suspect CECs (12 quantified with analytical standards), including parent compounds and metabolites of anti-inflammatories, antibiotics, antidepressants, sedatives, stimulants, and illicit drugs. High concentrations of these CECs were particularly evident near a Wastewater Treatment Plant (WWTP), where notable levels of compounds such as caffeine (4.02-15.03 ng L-1), ciprofloxacin (6.05 ng L-1), clindamycin (6.04-7.01 ng L-1), and diclofenac (1.36-2.20 ng L-1) were detected. Sediment samples exhibited the highest incidence of CECs, with caffeine reaching the highest concentration (55.89 μg kg-1). Ciprofloxacin (2.94 to 4.18 μg kg-1) was the sole CEC detected in biota samples. The ecotoxicological risk assessment indicated that the concentrations of all detected compounds posed significant ecotoxicity risks to the aquatic environment. In particular, caffeine and diclofenac presented considerable acute and chronic toxic risks to aquatic organisms, including algae, crustaceans, and fish. The Hazard Index (HI) values (3.65-7 to 8.06-8) suggest that ingesting ciprofloxacin at the concentrations found in fish does not represent a significant risk to human health. However, due to the reported risks to estuarine biota, it is crucial to continuously monitor the accumulation of these compounds in food widely consumed by the local population to assess potential impacts on human health.

Resilient water quality management: Insights from Japan's environmental quality standards for conserving aquatic life framework

Currently, chemicals and waste are recognized as key drivers of habitat degradation and biodiversity loss in aquatic ecosystems. To ensure vibrant habitats for aquatic species and maintain a sustainable aquatic food supply system, Japan promulgated its Environmental Quality Standards for the Conservation of Aquatic Life (EQS-CAL), based on its own aquatic life water quality criteria (ALWQC) derivation method and application mechanism. Here we overview Japan's EQS-CAL framework and highlight their best practices by examining the framework systems and related policies. Key experiences from Japan's EQS-CAL system include: (1) Classifying six types of aquatic organisms according to their adaptability to habitat status; (2) Using a risk-based chemical screening system for three groups of chemical pollutants; (3) Recommending a five-step method for determining ALWQC values based on the most sensitive life stage of the most sensitive species; (4) Applying site-specific implementation mechanisms through a series of Plan-Do-Check-Act loops. This paper offers scientific references for other jurisdictions, aiding in the development of more resilient ALWQC systems that can maintain healthy environments for aquatic life and potentially mitigate ongoing threats to human societies and global aquatic biodiversity.

Effects of acetaminophen exposure on behavior and erythrocyte nuclear morphology of juvenile Oreochromis niloticus

The occurrence of pharmaceuticals in the environment can have undesirable effects on nontarget animals, including fish. The present experiment assessed the effects of subchronic exposure to waterborne acetaminophen (N-acetyl-p-aminophenol) (APAP) on selected behavioral aspects (physical avoidance response, ventilation rate, and food detection rate) and erythrocyte nuclear abnormality (ENA) in juvenile Oreochromis niloticus. Two groups of fish were exposed to APAP dissolved in aged municipal water (T1: 2 mg/L and T2: 10 mg/L) for 8 weeks in three replicates (n = 7 fish per tank), alongside a control group (C) without APAP. APAP-exposed fish spent significantly (p < .05) longer time to detect food (T1: 32.6 ± 4.55 s and T2: 39.6 ± 4.66 s) compared to the control group (19.9 ± 2.46 s). Both APAP-exposed groups exhibited attenuated physical avoidance responses (76.7%, 68.7%, and 87.3% in T1, T2, and C, respectively) and a lower mean ventilation rate compared to the control group (194.5 ± 15.5, 179.1 ± 11.6, and 233.2 ± 19.0 per min in T1, T2, and C, respectively). The frequency occurrence of ENA types such as bi-nucleated, notched nuclei, lobed nuclei, and blebbed nuclei (except micronuclei) was significantly higher (p < .05) in APAP-exposed groups compared to the control, with more pronounced effects in the T2 group. The study concludes that APAP exposure prompts significant alterations in behavior and erythrocyte nuclear morphology, emphasizing the value of monitoring and regulating the entry of pharmaceuticals, including APAP, into aquatic environments to prevent unintended effects on non-target organisms like Oreochromis niloticus.

Pharmaceutical Pollution of the English National Parks

England's 10 national parks are renowned for their landscapes, wildlife, and recreational value. However, surface waters in the national parks may be vulnerable to pollution from human-use chemicals, such as active pharmaceutical ingredients (APIs), because of factors like ineffective wastewater treatment, seasonal tourism, a high proportion of elderly residents, and the presence of low-flow water bodies that limit dilution. The present study determined the extent of API contamination in the English national parks by monitoring 54 APIs in 37 rivers across all national parks over two seasons. Results were compared to existing data sets for UK cities and to concentration thresholds for ecological impacts and antimicrobial resistance selection. Results revealed widespread contamination of the national parks, with APIs detected at 52 out of 54 sites and in both seasons. Thirty-one APIs were detected, with metformin, caffeine, and paracetamol showing the highest mean concentrations and cetirizine, metformin, and fexofenadine being the most frequently detected. While total API concentrations were generally lower than seen previously in UK cities, locations in the Peak District and Exmoor had higher concentrations than most city rivers. Fourteen locations had concentrations of either amitriptyline, carbamazepine, clarithromycin, diltiazem, metformin, paracetamol, or propranolol above levels of concern for fish, invertebrates, and algae or for selection for antimicrobial resistance. Therefore, API pollution of the English national parks appears to pose risks to ecological health and potentially human health through recreational water use. Given that these parks are biodiversity hotspots with protected ecosystems, there is an urgent need for improved monitoring and management of pharmaceutical pollution and pollution more generally not only in national parks in England but also in similar environments across the world. Environ Toxicol Chem 2024;43:2422-2435. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Perspectives on chick embryo models in developmental and reproductive toxicity screening

Teratology, the study of congenital anomalies and their causative factors intersects with developmental and reproductive toxicology, employing innovative methodologies. Evaluating the potential impacts of teratogens on fetal development and assessing human risk is an essential prerequisite in preclinical research. The chicken embryo model has emerged as a powerful tool for understanding human embryonic development due to its remarkable resemblance to humans. This model offers a unique platform for investigating the effects of substances on developing embryos, employing techniques such as ex ovo and in ovo assays, chorioallantoic membrane assays, and embryonic culture techniques. The advantages of chicken embryonic models include their accessibility, cost-effectiveness, and biological relevance to vertebrate development, enabling efficient screening of developmental toxicity. However, these models have limitations, such as the absence of a placenta and maternal metabolism, impacting the study of nutrient exchange and hormone regulation. Despite these limitations, understanding and mitigating the challenges posed by the absence of a placenta and maternal metabolism are critical for maximizing the utility of the chick embryo model in developmental toxicity testing. Indeed, the insights gained from utilizing these assays and their constraints can significantly contribute to our understanding of the developmental impacts of various agents. This review underscores the utilization of chicken embryonic models in developmental toxicity testing, highlighting their advantages and disadvantages by addressing the challenges posed by their physiological differences from mammalian systems.

Metabolomic-Based Comparison of Daphnia magna and Japanese Medaka Responses After Exposure to Acetaminophen, Diclofenac, and Ibuprofen

Pharmaceuticals are found in aquatic environments due to their widespread use and environmental persistence. To date, a range of impairments to aquatic organisms has been reported with exposure to pharmaceuticals; however, further comparisons of their impacts across different species on the molecular level are needed. In the present study, the crustacean Daphnia magna and the freshwater fish Japanese medaka, common model organisms in aquatic toxicity, were exposed for 48 h to the common analgesics acetaminophen (ACT), diclofenac (DCF), and ibuprofen (IBU) at sublethal concentrations. A targeted metabolomic-based approach, using liquid chromatography-tandem mass spectrometry to quantify polar metabolites from individual daphnids and fish was used. Multivariate analyses and metabolite changes identified differences in the metabolite profile for D. magna and medaka, with more metabolic perturbations for D. magna. Pathway analyses uncovered disruptions to pathways associated with protein synthesis and amino acid metabolism with D. magna exposure to all three analgesics. In contrast, medaka exposure resulted in disrupted pathways with DCF only and not ACT and IBU. Overall, the observed perturbations in the biochemistry of both organisms were different and consistent with assessments using other endpoints reporting that D. magna is more sensitive to pollutants than medaka in short-term studies. Our findings demonstrate that molecular-level responses to analgesic exposure can reflect observations of other endpoints, such as immobilization and mortality. Thus, environmental metabolomics can be a valuable tool for selecting sentinel species for the biomonitoring of freshwater ecosystems while also uncovering mechanistic information. Environ Toxicol Chem 2024;43:1339-1351. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Trophic transfer of micro- and nanoplastics and toxicity induced by long-term exposure of nanoplastics along the rotifer (Brachionus plicatilis)-marine medaka (Oryzias melastigma) food chain

Microplastics (MPs) and nanoplastics (NPs) are emerging pollutants in the ocean, but their transfer and toxicity along the food chains are unclear. In this study, a marine rotifer (Brachionus plicatilis)-marine medaka (Oryzias melastigma) food chain was constructed to evaluate the transfer of polystyrene MPs and NPs (70 nm, 500 nm, and 2 μm, 2000 μg/L) and toxicity of 70 nm PS-NPs (0, 20, 200, and 2000 μg/L) on marine medaka after long-term food chain exposure. The results showed that the amount of 70 nm NPs accumulated in marine medaka was 1.24 μg/mg, which was significantly higher than that of 500 nm NPs (0.87 μg/mg) and 2 μm MP (0.69 μg/mg). Long-term food chain exposure to NPs caused microflora dysbiosis, resulting in activation of toll-like receptor 4 (TLR4) pathway, which induced liver inflammation. Moreover, NPs food chain exposure increased liver and muscle tissue triglyceride and lactate content, but decreased the protein, sugar, and glycogen content. NPs food chain exposure impaired reproductive function and inhibited offspring early development, which might pose a threat to the sustainability of marine medaka population. Overall, the study revealed the transfer of MPs and NPs and the effects of NPs on marine medaka along the food chain.

Tracing COVID-19 drugs in the environment: Are we focusing on the right environmental compartment?

The Coronavirus Disease 2019 (COVID-19) pandemic led to over 770 million confirmed cases, straining public healthcare systems and necessitating extensive and prolonged use of synthetic chemical drugs around the globe for medical treatment and symptom relief. Concerns have arisen regarding the massive release of active pharmaceutical ingredients (APIs) and their metabolites into the environment, particularly through domestic sewage. While discussions surrounding this issue have primarily centered on their discharge into aquatic environments, particularly through treated effluent from municipal wastewater treatment plants (WWTPs), one often overlooked aspect is the terrestrial environment as a significant receptor of pharmaceutical-laden waste. This occurs through the disposal of sewage sludge, for instance, by applying biosolids to land or non-compliant disposal of sewage sludge, in addition to the routine disposal of expired and unused medications in municipal solid wastes. In this article, we surveyed sixteen approved pharmaceuticals for treating COVID-19 and bacterial co-infections, along with their primary metabolites. For this, we delved into their physiochemical properties, ecological toxicities, environmental persistence, and fate within municipal WWTPs. Emphasis was given on lipophilic substances with log Kow >3.0, which are more likely to be found in sewage sludge at significant factions (25.2%-75.0%) of their inputs in raw sewage and subsequently enter the terrestrial environment through land application of biosolids, e.g., 43% in the United States and as high as 96% in Ireland or non-compliant practices of sewage sludge disposal in developing communities, such as open dumping and land application without prior anaerobic digestion. The available evidence underscores the importance of adequately treating and disposing of sewage sludge before its final disposal or land application in an epidemic or pandemic scenario, as mismanaged sewage sludge could be a significant vector for releasing pharmaceutical compounds and their metabolites into the terrestrial environment.

Multiple biomarker responses in female Clarias gariepinus exposed to acetaminophen

Several authors have documented the presences of acetaminophen (APAP) in both surface and groundwater and have received attention from government agencies and basic authorities across the globe. The impacts of such pharmaceutical products on non-target organism like fish are underestimated as a result of selected investigation using few biomarkers. We evaluated the sub-chronic impacts of APAP in female catfish (Clarias gariepinus) using multiple biomarkers. The exposure of female catfish to APAP induced oxidative stress. Markers such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and total antioxidant capacity (TAC) were significantly higher in all exposed groups. Exposure of Clarias gariepinus to APAPA caused histological alterations in the gills (fusion and shortening of some filaments, hyperplasia of the epithelial gill cells, aneurism, congestion, and epithelial rupture of the gills), liver (apoptotic hyperplasia, sinusoidal congestion, and necrosis of the hepatocytes), and gonad (degenerated follicles and ovarian apoptosis). Furthermore, multivariate results indicated that there was a distinct response from the acetaminophen-exposed female catfish, with over 95% of the biomarkers significantly contributing to the discrimination between the acetaminophen-exposed female catfish and the control groups. Our research provides evidence supporting the use of a multiple biomarker approach to evaluate the impacts of drugs on the health status of exposed fish.

Emerging micropollutants in aquatic ecosystems and nanotechnology-based removal alternatives: A review

There is a significant concern about the accessibility of uncontaminated and safe drinking water, a fundamental necessity for human beings. This concern is attributed to the toxic micropollutants from several emission sources, including industrial toxins, agricultural runoff, wastewater discharges, sewer overflows, landfills, algal blooms and microbiota. Emerging micropollutants (EMs) encompass a broad spectrum of compounds, including pharmaceutically active chemicals, personal care products, pesticides, industrial chemicals, steroid hormones, toxic nanomaterials, microplastics, heavy metals, and microorganisms. The pervasive and enduring nature of EMs has resulted in a detrimental impact on global urban water systems. Of late, these contaminants are receiving more attention due to their inherent potential to generate environmental toxicity and adverse health effects on humans and aquatic life. Although little progress has been made in discovering removal methodologies for EMs, a basic categorization procedure is required to identify and restrict the EMs to tackle the problem of these emerging contaminants. The present review paper provides a crude classification of EMs and their associated negative impact on aquatic life. Furthermore, it delves into various nanotechnology-based approaches as effective solutions to address the challenge of removing EMs from water, thereby ensuring potable drinking water. To conclude, this review paper addresses the challenges associated with the commercialization of nanomaterial, such as toxicity, high cost, inadequate government policies, and incompatibility with the present water purification system and recommends crucial directions for further research that should be pursued.

Tracking drugged waters from various sources to drinking water-its persistence, environmental risk assessment, and removal techniques

Pharmaceuticals have become a major concern due to their nature of persistence and accumulation in the environment. Very few studies have been performed relating to its toxicity and ill effects on the aquatic/terrestrial flora and fauna. The typical wastewater and water treatment processes are not efficient enough to get these persistent pollutants treated, and there are hardly any guidelines followed. Most of them do not get fully metabolized and end up in rivers through human excreta and household discharge. Various methods have been adopted with the advancement in technology, sustainable methods are more in demand as they are usually cost-effective, and hardly any toxic by-products are produced. This paper aims to illustrate the concerns related to pharmaceutical contaminants in water, commonly found drugs in the various rivers and their existing guidelines, ill effects of highly detected pharmaceuticals on aquatic flora and fauna, and its removal and remediation techniques putting more emphasis on sustainable processes.

The occurrence of emerging compounds in real urban wastewater before and after the COVID-19 pandemic in Cali, Colombia

The COVID-19 pandemic is considered one of the most significant global disasters in the last years. The rapid increase in infections, deaths, treatment, and the vaccination process has resulted in the excessive use of pharmaceuticals that have entered the environment as micropollutants. Considering the prior information about the presence of pharmaceuticals found in the wastewater of Cali, Colombia, which was collected from 2015 to 2022. The data monitored after the COVID-19 pandemic showed an increase in the concentration of analgesics and anti-inflammatory drugs of up to 91%. This increase was associated with the consumption of pharmaceuticals for mild symptoms, such as fever and pain. Moreover, the increase in concentration of pharmaceuticals poses a highly ecological threat, which was up to 14 times higher than that reported before of COVID-19 pandemic. These results showed that the COVID-19 had not only impacted human health but also had an effect on environmental health.

A critical review on paracetamol removal from different aqueous matrices by Fenton and Fenton-based processes, and their combined methods

Paracetamol (PCT), also known as acetaminophen, is a drug used to treat fever and mild to moderate pain. After consumption by animals and humans, it is excreted through the urine to the sewer systems, wastewater treatment plants, and other aquatic/natural environments. It has been detected in trace amounts in effluents of wastewater plant treatments, sewage sludge, hospital wastewaters, surface waters, and drinking water. PCT can cause genetic code damage, oxidative degradation of lipids, and denaturation of protein in cells, and its toxicity has been well-proven in bacteria, algae, macrophytes, protozoan, and fishes. To avoid its harmful health problems over living beings, powerful Fenton and Fenton-based treatments as pre-eminent advanced oxidation processes (AOPs) have been developed because of the inefficient treatment by conventional treatments. This paper presents a comprehensive and critical review over the application of such Fenton technologies to remove PCT from natural waters, synthetic wastewaters, and real wastewaters. The characteristics and main results obtained using Fenton, photo-Fenton, electro-Fenton, and photoelectro-Fenton are described, making special emphasis in the oxidative action of the generated reactive oxygen species. Hybrid processes based on the coupling with ultrasounds, gamma radiation, photocatalysis, photoelectrocatalysis, zero-valent iron-activated persulfate, adsorption, and microbial fuel cells, are analyzed. Sequential treatments involving the initiation with plasma gliding arc discharge and post-biological process are detailed. Comparative results with other available AOPs are also described and discussed. Finally, 13 aromatic by-products and 9 short-linear aliphatic carboxylic acid detected during the PCT removal by Fenton and Fenton-based processes are reported, with the proposal of three parallel pathways for its initial degradation.

An alternative approach to the kinetic modeling of pharmaceuticals degradation in high saline water by electrogenerated active chlorine species

A semiempirical approach considering the rate of reactive chlorine species-RCS- production (Φ_E) as a function of current and Cl^- concentration for the modeling of acetaminophen (ACE) degradation is presented. A filter-press reactor having a Ti/RuO₂-ZrO₂ (Sb₂O₃ doped) anode, NaCl (0.04-0.1 mol L^-1) as supporting electrolyte, and operated in continuous mode, was considered. A current of 100 mA and a flow of 11 mL min^-1 favored the electrogeneration of RCS and ACE degradation. Hydraulic retention time and Φ_E were the most relevant parameters for the RCS production. These two parameters, plus the pollutant concentration, were very determinant for the ACE degradation. The model successfully reproduced the ACE removal in distilled water at different concentrations (10, 20, 40, and 60 mg L^-1). The electrochemical system achieved removals between 80 and 100% of ACE in distilled water. The ACE treatment in actual seawater (a chloride-rich matrix, 0.539 mol L^-1 of Cl^-) was assessed, and the degradation was simulated using the developed model. The competing role toward electrogenerated RCS by intrinsic organic matter (3.2 mg L^-1) in the seawater was a critical point, and the simulated values fitted well with the experimental data. Finally, the action of the electrochemical system on ciprofloxacin (CIP) in real seawater and its antimicrobial activity was tested. CIP removal (100% at 120 s) was faster than that observed for ACE (100% of degradation after 180 s) due to CIP has amine groups that are more reactive toward RCS than phenol moiety on ACE. Moreover, the system removed 100% of the antimicrobial activity associated with CIP, indicating a positive environmental effect of the treatment.

Spent waste from edible mushrooms offers innovative strategies for the remediation of persistent organic micropollutants: A review

Urgent and innovative strategies for removal of persistent organic micropollutants (OMPs) in soil, groundwater, and surface water are the need of the hour. OMPs detected in contaminated soils and effluents from wastewater treatment plants (WWTPs) are categorized as environmentally persistent pharmaceutical pollutants (EPPPs), and endocrine disrupting chemicals (EDCs), their admixture could cause serious ecological issues to the non-target species. As complete eradication of OMPs is not possible with the extant conventional WWTPs technology, the inordinate and reckless application of OMPs negatively impacts environmental regenerative and resilience capacity. Therefore, the cardinal focus of this review is the bioremediation of persistent OMPs through efficient application of an agro-waste, i.e. spent mushroom waste (SMW). This innovative, green, long-term strategy embedded in the circular economy, based on state of the art information is comprehensively assessed in this paper. SMW accrues ligninolytic enzymes such as laccase and peroxidase, with efficient mechanism to facilitate biodegradation of recalcitrant organic pollutants. It is vital in this context that future research should address immobilization of such enzymes to overcome quantitative and qualitative issues obstructing their widespread use in biodegradation. Therefore, dual benefit is gained from cultivating critical cash crops like mushrooms to meet the escalating demand for food resources and to aid in biodegradation. Hence, mushroom cultivation has positive environmental, social, and economic implications in developing countries like India.

A review on the degradation of acetaminophen by advanced oxidation process: pathway, by-products, biotoxicity, and density functional theory calculation

Water scarcity and the accumulation of recalcitrance compounds into the environment are the main reasons behind the attraction of researchers to use advanced oxidation processes (AOPs). Many AOP systems have been used to treat acetaminophen (ACT) from an aqueous medium, which leads to generating different kinetics, mechanisms, and by-products. In this work, state-of-the-art studies on ACT by-products and their biotoxicity, as well as proposed degradation pathways, have been collected, organized, and summarized. In addition, the Fukui function was used for predicting the most reactive sites in the ACT molecule. The most frequently detected by-products in this review were hydroquinone, 1,4-benzoquinone, 4-aminophenol, acetamide, oxalic acid, formic acid, acetic acid, 1,2,4-trihydroxy benzene, and maleic acid. Both the experimental and prediction tests revealed that N-(3,4-dihydroxy phenyl) acetamide was mutagenic. Meanwhile, N-(2,4-dihydroxy phenyl) acetamide and malonic acid were only found to be mutagenic in the prediction test. The findings of the LC50 (96 h) test revealed that benzaldehyde is the most toxic ACT by-products and hydroquinone, N-(3,4-dihydroxyphenyl)formamide, 4-methylbenzene-1,2-diol, benzoquinone, 4-aminophenol, benzoic acid, 1,2,4-trihydroxybenzene, 4-nitrophenol, and 4-aminobenzene-1,2-diol considered harmful. The release of them into the environment without treatment may threaten the ecosystem. The degradation pathway based on the computational method was matched with the majority of ACT proposed pathways and with the most frequent ACT by-products. This study may contribute to enhance the degradation of ACT by AOP systems.

Microplastics increase the accumulation of phenanthrene in the ovaries of marine medaka (Oryzias melastigma) and its transgenerational toxicity

Microplastics (MPs) are considered to exacerbate the impacts of hydrophobic organic pollutants on aquatic organisms through the carrier function, but whether MPs affect the transgenerational toxicity of pollutants is unclear. This study exposed adult female marine medaka to phenanthrene (Phe)-adsorbed MPs for 60 days to investigate the effects of MPs on the bioaccumulation, reproductive and transgenerational toxicity of Phe. Compared to Phe alone, co-exposure to Phe and 200 μg/L MPs significantly increased Phe bioaccumulation in the intestines and ovaries. Phe alone and Phe combined with MPs disrupted the regulation of the hypothalamus-pituitary-gonadal axis, and reduced vitellogenin levels and reproductive capacity of female fish. In particular, co-exposure to 200 μg/L MPs and Phe increased the rate of follicular atresia, inhibited ovarian maturity, and aggravated reproductive toxicity. Notably, maternal uptake of Phe could be transferred to the offspring, and embryonic accumulation increased with the concentrations of MPs. Moreover, MPs aggravated Phe-induced bradycardia in embryos, suggesting that MPs exacerbated the transgenerational toxicity of Phe. These findings reveal that the growing number of MPs in the ocean might amplify the adverse effects of organic pollutants on the health and population stability of marine fishes, and this problem merits more attention.

Minute Cu2+ coupling with HCO3- for efficient degradation of acetaminophen via H2O2 activation

Homogeneous Cu²⁺-mediated activation of H₂O₂ has been widely applied for the removal of organic contaminants, but fairly high dosage of Cu²⁺ is generally required and may cause secondary pollution. In the present study, minute Cu²⁺ (2.5 μM) catalyzed H₂O₂ exhibited excellent efficiency in degradation of organic pollutants with the assistant of naturally occurring level HCO₃^- (1 mM). In a typical case, acetaminophen (ACE) was completely eliminated within 10 min which followed the pseudo-first-order kinetics. Singlet oxygen and superoxide radical rather than traditionally identified hydroxyl radical were the predominant reactive oxygen species (ROS) responsible for ACE degradation. Meanwhile, Cu³⁺ was deduced through Cu⁺ and p-hydroxybenzoic acid formation analysis. CuCO₃(aq) was the main complex with high reactivity for the activation of H₂O₂ to form ROS and Cu³⁺. The removal efficiency of ACE depended on the operating parameters, such as Cu²⁺, HCO₃^- and H₂O₂ dosage, solution initial pH. The presence of Cl^-, HPO₄^2-, humic acid were found to retard ACE removal while other anions such as SO₄^2- and NO₃^- had no obvious effect. ACE exhibited lower degradation efficiency in real water matrices than that in ultra-pure water. Nevertheless, 58-100% of ACE was removed from domestic wastewater, lake water and tap water within 60 min. Moreover, eight intermediate products were identified and the possible degradation pathways of ACE were proposed. Additionally, other typical organic pollutants including bisphenol A, norfloxacin, lomefloxacin hydrochloride and sulfadiazine, exhibited great removal efficiency in the Cu²⁺/H₂O₂/HCO₃^- system.