Search

Ribavirin (RBV), which is extensively used to treat viral diseases such as COVID-19, is considered one of the major emerging contaminants due to its long-term existence and health risk in the aqueous environmental system. However, research on effective removal of RBV still remains insufficient. In this study, we investigated the RBV degradation kinetics and mechanism in UV/chlorine/Fe(II) process. The degradation rate constant kobs-RBV of RBV was 2.52 × 10−4 s−1 in UV/chlorine/Fe(II) process, which increased by 1.6 times and 1.3 times than that in chlorine alone and UV/chlorine process, respectively. Notably, trace amount Fe(II) promoted RBV degradation in UV/chlorine system through Fe2+/Fe3+ cycles, enhancing the yield of reactive species such as HO· and certain species reactive chlorine radicals (RCS). The contributions of HO· and RCS toward RBV degradation were 53.91% and 16.11%, respectively. Specifically, Cl·, ClO·, and Cl2·− were responsible for 8.59%, 2.69%, and 4.83% of RBV removal. The RBV degradation pathway indicated that the reactive species preferentially attacked the amide moiety of RBV, which cleaved the ether bond and the hydroxyl group. The toxicity evaluation of RBV degradation products elucidated that UV/chlorine/Fe(II) process was beneficial for RBV detoxification. [ABSTRACT FROM AUTHOR]

Fungal diseases cause substantial loss to agricultural crops, affecting both quantities and quality. Although several methods are used for preventing disease incidence, fungicides remain crucial for higher yields and better quality. But in the past, the efficacy of several fungicides has decreased due to increased cases of fungicide resistant. In our pursuit of new effective fungicides, we synthesised a series of twenty 2-Indazol-1-yl-chromen-4-one derivatives (6a- 6t). The characterization of synthesized compounds was performed by several spectroscopic methods including Infrared, Nuclear Magnetic Resonance (¹H and 13C) and HRMS. Out of 20 synthesised compounds, 19 (6b- 6t) were found to be novel. All synthesised indazolylchromones showed very good antifungal activity against Sclerotium rolfsii and Fusarium oxysporum. Among the tested compounds, 6t and 6f exhibited very good fungicidal activity against S. rolfsii with an ED50 of 10.10 mg L-1 and 16.18 mg L[sup -1], respectively. In case of Fusarium oxysporum compound 6f displayed good' activity with an ED50 value of 27.82 mg L-1. Molecular docking study was done to predict the binding sites of most active compounds, 6t and 6f with Cytochrome P450 14alpha -sterol demethylase (CYP51) enzyme using molsoft software. The acute toxicity predictions the of synthesized compounds for fish (LC50,96 Hr), daphnid (LC50, 48 Hr) and green algae (EC50, 96Hr) and the chronic toxicity predictions (ChV) were assessed using Ecological Structure Activity Relationship (ECOSAR) model. As per ECOSAR prediction, all the chemicals are inside AD and not missing predictions. [ABSTRACT FROM AUTHOR]

Fungal diseases cause substantial loss to agricultural crops, affecting both quantities and quality. Although several methods are used for preventing disease incidence, fungicides remain crucial for higher yields and better quality. But in the past, the efficacy of several fungicides has decreased due to increased cases of fungicide resistant. In our pursuit of new effective fungicides, we synthesised a series of twenty 2-Indazol-1-yl-chromen-4-one derivatives (6a- 6t). The characterization of synthesized compounds was performed by several spectroscopic methods including Infrared, Nuclear Magnetic Resonance (1H and 13C) and HRMS. Out of 20 synthesised compounds, 19 (6b- 6t) were found to be novel. All synthesised indazolylchromones showed very good antifungal activity against Sclerotium rolfsii and Fusarium oxysporum. Among the tested compounds, 6t and 6f exhibited very good fungicidal activity against S. rolfsii with an ED50 of 10.10 mg L-1 and 16.18 mg L-1, respectively. In case of Fusarium oxysporum compound 6f displayed good’ activity with an ED50 value of 27.82 mg L-1. Molecular docking study was done to predict the binding sites of most active compounds, 6t and 6f with Cytochrome P450 14alpha -sterol demethylase (CYP51) enzyme using molsoft software. The acute toxicity predictions the of synthesized compounds for fish (LC50,96 Hr), daphnid (LC50, 48 Hr) and green algae (EC50, 96Hr) and the chronic toxicity predictions (ChV) were assessed using Ecological Structure Activity Relationship (ECOSAR) model. As per ECOSAR prediction, all the chemicals are inside AD and not missing predictions.

Empirical and in silico data on the aquatic ecotoxicology of 2697 organic chemicals were collected in order to compile a dataset for assessing the predictive power of current Quantitative Structure Activity Relationship (QSAR) models and software platforms. This document presents the dataset and the data pipeline for its creation. Empirical data were collected from the US EPA ECOTOX Knowledgebase (ECOTOX) and the EFSA (European Food Safety Authority) report “Completion of data entry of pesticide ecotoxicology Tier 1 study endpoints in a XML schema – database”. Only data for OECD recommended algae, daphnia and fish species were retained. QSAR toxicity predictions were calculated for each chemical and each of six endpoints using ECOSAR, VEGA and the Toxicity Estimation Software Tool (T.E.S.T.) platforms. Finally, the dataset was amended with SMILES, InChIKey, pKa and logP collected from webchem and PubChem.

Pyriclobenzuron 11 PBU – pyriclobenzuron.(PBU) is a novel molluscicide developed to control Pomacea canaliculate, and little information on its environmental fate has been published. In this study, the photolysis of PBU in an aqueous environment was simulated using a xenon lamp. Results showed that the photolysis of PBU in water followed first-order kinetics, exhibiting a t0.5 of 95.1 h and 83.6 h in Milli-Q water and river water, respectively. Two main photolysis products 22 PPs – photolysis products.(PPs) were detected by HPLC-UV and identified by UPLC-Q/TOF MS, which were formed via the hydroxylation and photocatalytic hydro-dehalogenation of PBU, respectively. The initial relative abundance of photolysis product 1 33 PP-1 – photolysis product 1.(PP-1) in Milli-Q water was 1.55 times higher than that in river water. PP-1 was detected at 26.5 % and 76.8 % of the maximum relative abundance in the river water and Milli-Q water after 720 h, respectively. Photolysis product 2 44 PP-2 – photolysis product 2.(PP-2) was stable in water because of its weak hydrophilicity. The PP-2 detected after 720 h in Milli-Q water and river water was 93.7 % and 93.5 % of the maximum relative abundance, respectively. Finally, ECOSAR software was used to evaluate the acute aquatic toxicity of PBU and its PPs, revealing that the PPs had lower toxicity levels to non-target aquatic organisms.

This study explores the photocatalytic transformation of the antiviral drug abacavir employing different advanced oxidation processes (AOPs) such as UV/TiO2, UV/MOF/H2O2, UV/MOF/S2O82−, UV/Fe2+/H2O2, and UV/Fe2+/S2O82−. All processes appear to be effective in eliminating abacavir within a few minutes, while the evolution profile of the basic transformation product, descyclopropyl-abacavir (TP-247) was also monitored. Moreover, the implementation of the most efficient technologies towards the removal of abacavir in different matrices such as wastewater effluent and leachate was also assessed, revealing that the organic matter present or the inorganic constituents can retard the whole process. Four major transformation products were detected, and their time-evolution profiles were recorded in all studied matrices, revealing that different transformation pathways dominate in each matrix. Finally, the prediction of the toxicity of the major TPs employing ECOSAR software was conducted and showed that only hydroxylation can play a detoxification role in the treated solution. [ABSTRACT FROM AUTHOR]

The fungicides imazalil, penconazole and tebuconazole have been added to the 3rd EU watchlist due to their persistence and hazard to the environment. In vitro ecotoxicity studies against organisms such as Daphnia magna and Danio rerio have indicated the harmfulness. To prevent penetration of these substances into the aquatic environment, advanced cleaning stages are being tested for wastewater treatment plants, including ultraviolet radiation. Yet, the exposure of the compounds may result in transformation products whose ecotoxicity determination proves difficult due to the lack of reference standards. Alleviation comes from in silico methods such as quantitative structure activity relationship (QSAR) analysis and the determination of time-depended ecotoxicity equivalents (ETE) which combines chemical kinetics of the photoinduced degradation process and in silico predicted ecotoxicity of the transformation products. QSAR analysis was used to predict the ecotoxicity of the transformation products whose structures were elucidated with the help of high-resolution multifragmentation mass spectrometry. Predicted values were compared to the results of in vitro ecotoxicity assays from previous studies and found in agreement. All photoinduced products were described as subsequent or subsequent follow-up reaction products. Time-independent ETEs revealed that the degradation of the fungicide itself had the greatest effect on the ecotoxicity of the irradiated solution, as photoinduced transformation products were found of significantly lower amount in irradiated solution and of lesser ecotoxicological hazard than the fungicide. The method may help estimating the conditions needed for application of UV irradiation in an advanced purification step in wastewater treatment plants.

Bioconcentration factors (BCFs) are markers of chemical substance accumulation in organisms, and they play a significant role in determining the environmental risk of various chemicals. Experiments to obtain BCFs are expensive and time-consuming; therefore, it is better to estimate BCF early in the chemical development process. The current research aims to evaluate the ecotoxicity potential of 122 pharmaceuticals and identify possible important structural attributes using BCF as the determining feature against a group of fish species. We have calculated the theoretical 2D descriptors from the OCHEM platform and SiRMS descriptor calculating software. The regression-based quantitative structure–property relationship (QSPR) modeling was used to identify the chemical features responsible for acute fish bioconcentration. Multiple models with the “intelligent consensus” algorithm were employed for the regression-based approach improving the predictive ability of the models. To ensure the robustness and interpretability of the developed models, rigorous validation was performed employing various statistical internal and external validation metrics. From the developed models, it can be specified that the presence of large lipophilic and electronegative moieties greatly enhances the bioaccumulative potential of pharmaceuticals, whereas the hydrophilic characteristics have shown a negative impact on BCF. Furthermore, the developed models were employed to screen the DrugBank database (https://go.drugbank.com/) for assessing the BCF properties of the entire database. The evidence acquired from the modeled descriptors might be used for aquatic risk assessment in the future, with the added benefit of providing an early caution of their probable negative impact on aquatic ecosystems for regulatory purposes.

In this study, the acute toxicity effects of a fluorescent xanthene dye, Rhodamine B (RhB), widely used in textile, paper, and leather industries was investigated on a freshwater microalgae Chlorella vulgaris. The acute toxicity of RhB on C. vulgaris was determined by examining the growth, cell morphology, pigment production, protein content, and the activities of oxidative stress enzymes. Based on the results of the toxicity study of 24–96 h, the median inhibitory concentration (IC50) values ranged from 69.94 to 31.29 mg L−1. The growth of C. vulgaris was conspicuously inhibited by RhB exposure, and the cell surfaces appeared to be seriously shrunk in SEM analysis. The growth of C. vulgaris was hindered after exposure to graded concentrations (10–50 mg L−1) of RhB. A significant reduction in growth rate, pigment synthesis (chlorophyll a, chlorophyll b, and carotenoid), and protein content was recorded in a dose-dependent manner. After 96 h exposure of C. vulgaris to 50 mg L−1 RhB, chlorophyll a, chlorophyll b, carotenoids, and protein contents were reduced by 71.59, 74.90, 65.84, and 74.20%, respectively. The activities of the antioxidant enzymes peroxidase (POD), and catalase (CAT) also increased markedly in the presence of RhB. A notable effect was observed on oxidative enzymes catalase and peroxidase, indicating that oxidative stress may be the primary factor in the inhibition of growth and pigment synthesis. Consequently, the experimental acute toxicity data were compared to the QSAR prediction made by the ECOSAR programme. Results showed that the experimental acute toxicity values were 67.74-fold lower than the ECOSAR predicted values. The study provides convincing evidence for the metabolic disruption in the ubiquitous microalgae C. vulgaris due to the RhB dye toxicity. [ABSTRACT FROM AUTHOR]

Sulfamethoxazole (SMX) is a typical antibiotic in the world, which is frequently detected in the aquatic environment. The current study was aimed to investigate the SMX degradation in secondary treated wastewater using potassium Ferrate [Fe(VI)]. The effects of various experimental conditions, EDTA and phosphate as chelating agents, and toxicity assessment were also considered. Secondary treated effluent was spiked with predefined SMX concentrations, and after desired reaction time with Fe(VI), residual SMX was measured using HPLC. Results indicated that SMX degradation by Fe(VI) was favored under acidic condition, where 90% of SMX degradation was achieved after 120 min. Fe(VI) and SMX reaction obeyed first-order kinetic; meantime, the SMX degradation rate under pH 3 was 7.6 times higher than pH 7. The presence of phosphate (Na2HPO4) and EDTA declined SMX degradation, while Fe (III) effect was contradictory. In addition to promising demolition, 10% TOC removal was achieved. Eighteen major intermediates were identified using LC-MS/MS and the degradation pathways were suggested. Transformation products (TPs) were formed due to hydroxylation, bond cleavage, transformation after bond cleavage, and oxidation reactions. The ECOSAR analysis showed that some of the SMX oxidation products were toxic to aquatic organisms (fish, daphnia and green algae). [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous in the environment. Unlike other persistent chemicals, PFAS are highly soluble in water and tend to partition to surface and groundwater rather than soil and sediment. While numerous studies have evaluated the potential ecological effects of certain PFAS, there remain data gaps, especially for newer PFAS. Consequently, this study evaluated a high-throughput in silico approach for a screening-level risk assessment of PFAS in aquatic species. We focused on two well-studied PFAS, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), to provide a better context to our estimates. The Ecological Structural Activity Relationships (ECOSAR) program was used to estimate acute and chronic toxicity thresholds for fish, Daphnid, mysid, and green algae. The Exposure and Fate Assessment Screening Tool (E-FAST) model was used to derive estimated environmental concentrations (EECs) in surface water following hypothetical discharges from wastewater treatment plants (WWTPs). The predicted toxicity thresholds and EECs were compared to reported values. Subsequently, risk quotients (RQs) were calculated. We showed that (1) the acute toxicity thresholds for PFOA and PFOS were typically lower (i.e., more conservative) than reported values, whereas chronic toxicity thresholds were typically in the range of reported values, (2) the EECs were in the range of reported environmental concentrations in most cases, and (3) the acute and chronic RQs were mostly below the levels of concern. Additionally, the study highlighted that even for the well-studied PFOA and PFOS, there were still data gaps with regards to ecotoxicity in certain aquatic species as well as environmental concentrations for certain water bodies.

This study explores the photocatalytic transformation of the antiviral drug abacavir employing different advanced oxidation processes (AOPs) such as UV/TiO2, UV/MOF/H2O2, UV/MOF/S2O82−, UV/Fe2+/H2O2, and UV/Fe2+/S2O82−. All processes appear to be effective in eliminating abacavir within a few minutes, while the evolution profile of the basic transformation product, descyclopropyl-abacavir (TP-247) was also monitored. Moreover, the implementation of the most efficient technologies towards the removal of abacavir in different matrices such as wastewater effluent and leachate was also assessed, revealing that the organic matter present or the inorganic constituents can retard the whole process. Four major transformation products were detected, and their time-evolution profiles were recorded in all studied matrices, revealing that different transformation pathways dominate in each matrix. Finally, the prediction of the toxicity of the major TPs employing ECOSAR software was conducted and showed that only hydroxylation can play a detoxification role in the treated solution.

Wastewater release in an urban wetland in Mexico City entails discharging complex mixtures of hundreds of chemical substances into the aquatic system. Therefore, in order to identify the most important contaminants, a GC–MS screening method coupled with deconvolution software was used. LC50 values from ECOSAR and Toxic Units were obtained to identify the organic pollutants-of-concern and to pinpoint the most ecotoxic sites. The results showed that, even though the area has intensive farming, agrochemicals are not of concern. Industrial and domestic groups make up from about 30%–66% of the pollutants for all sites. Of the 189 identified substances, 17 were detected 44% of the time and the Toxic Unit showed that terbutol, coprostanol, and hexadecane were capable of generating considerable adverse effects on the aquatic ecosystem. Total Toxic Units for each site exhibited a decreasing trend as they distanced from the urban and agricultural area. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes such as thermal plasma activation and UV-C/H 2 O 2 treatment are considered as applications for the degradation of pharmaceutical residues in wastewater complementary to conventional wastewater treatment. It is supposed that direct oxidative treatment can lower the toxicity of hospital sewage water (HSW). The aim of this study was to predict the ecotoxicity for three aquatic species before and after oxidative treatment of 10 quantified pharmaceuticals in hospital sewage water. With the application of oxidative chemistry, pharmaceuticals are degraded into transformation products before reaching complete mineralization. To estimate the potential ecotoxicity for fish, Daphnia and green algae ECOSAR quantitative structure-activity relationship software was used. Structure information from pristine pharmaceuticals and their oxidative transformation products were calculated separately and in a mixture computed to determine the risk quotient (RQ). Calculated mixture toxicities for 10 compounds found in untreated HSW resulted in moderate-high RQ predictions for all three aquatic species. Compared to untreated HSW, 30-min treatment with thermal plasma activation or UV-C/H 2 O 2 resulted in lowered RQs. For the expected transformation products originating from fluoxetine, cyclophosphamide and acetaminophen increased RQs were predicted. Prolongation of thermal plasma oxidation up to 120 min predicted low-moderate toxicity in all target species. It is anticipated that further degradation of oxidative transformation products will end in less toxic aliphatic and carboxylic acid products. Predicted RQs after UV-C/H 2 O 2 treatment turned out to be still moderate-high. In conclusion, in silico extrapolation of experimental findings can provide useful predicted estimates of mixture toxicity. However due to the complex composition of wastewater this in silico approach is a first step to screen for ecotoxicity. It is recommendable to confirm these predictions with ecotoxic bioassays. [Display omitted] • Advanced oxidation processes can be applied to degrade pharmaceutical residues. • Moderate to high toxicity was predicted for untreated hospital sewage water (HSW). • Ecotoxicity of oxidatively treated HSW was estimated using ECOSAR software. • Thermal plasma and UV-C/H 2 O 2 oxidation result in reduced estimated risk quotients. • In silico toxicity predictions are useful to inform laboratory testing strategies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Co–Cu@g-C 3 N 4 /PMS system exhibited excellent performance for many pollutants removal. • Quenching and EPR analysis indicated both SO 4 − and 1O 2 were the dominant ROS. • Fukui index was calculated to elucidate the possible degradation pathways. • ECOSAR analysis indicated the ecotoxicity of most products was lower than SMX. Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs) have shown great potential for recalcitrant contaminants removal in wastewater treatment. Herein, we report the efficient activation of PMS by bimetallic oxides (cobalt and copper) co-doped graphitic carbon nitride (Co–Cu@g-C 3 N 4) for removal of sulfamethoxazole (SMX). The morphology and chemical composition of the fresh and used Co–Cu@g-C 3 N 4 were characterized by TEM, SEM, XRD, BET, and XPS. Nearly complete removal of SMX (50 mg/L) was observed in the presence of 50 mg/L Co–Cu@g-C 3 N 4 , 0.5 mmol/L PMS within 20 min at neutral pH with a degradation rate of 0.137 min−1. Moreover, the Co–Cu@g-C 3 N 4 catalyst enabled more than 90 % removal of various typical pollutants within 20 min, including sulfapyridine, rhodamine B, acridine red, and malachite green, with rate constants of 0.083, 0.130, 0.096, and 0.160 min−1, respectively. Quenching experiments and electron paramagnetic resonance (EPR) analysis demonstrated that sulfate radical (SO 4 −) and singlet oxygen (1O 2) were collectively responsible for SMX degradation. The efficient activation of PMS by Co–Cu@g-C 3 N 4 was ascribed to the continuous conversion of Co(Ⅲ) to Co(Ⅱ) and Cu(I) to Cu(ⅠI), and the presence of oxygen vacancy (O V) on the catalyst. The Co–Cu@g-C 3 N 4 /PMS system exhibited superior durability and maintained high efficiency in real water samples. Finally, theoretical calculations of Fukui index were performed to determine the possible degradation pathways of SMX, and the ecotoxicity of the degradation products was evaluated by the ECOSAR program. This study significantly advances the understanding of the reaction between PMS and bimetallic oxides catalysts, as well facilitates the development and application of PMS-based AOPs in wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • FeBDC-NH 2 , is used as a dual functional catalyst for activating PDS to degrade BMI. • FeBDC-NH 2 shows more visible-light enhancement than FeBDC for activating PDS. • FeBDC-NH 2 can lead to a significantly lower Ea of BMI degradation than reported values. • DFT calculation is performed to elucidate degradation process of BMI by FeBDC-NH 2. • Eco-toxicity of BMI degradation intermediates is evaluated to study implication. Ionic liquids (ILs) are increasingly adopted in various applications, leading to their release into the water environment, where they pose potential threats to ecology in view of toxicities. In order to remove 1-n-Butyl-3-Methylimidazolium (BMI) chloride, a well-known model IL, from water, urgent and crucial techniques are needed. Peroxydisulfate (PDS) activated by heterogeneous catalysts is useful for BMI degradation; nonetheless, heterogeneously activated PDS has been utilized in very few studies. A Fe-based metal–organic framework, Fe-2-aminobenzene-1,4-dicarboxylic acid (FeBDC-NH 2), is suggested here for serving as an activator because of its Fe sites, high surface areas, porosities, and visible-light responsive photocatalytic activity. The structure–property relationship of FeBDC-NH 2 in PDS activation is compared to that of Fe-Benzene-1,4-dicarboxylic acid (FeBDC), and both are found to activate PDS to degrade BMI. FeBDC-NH 2 , however, significantly accelerated BMI degradation when exposed to visible light. Compared to activation energies reported by other oxidation approaches, the activation energy of BMI degradation is considerably lower. Through theoretical DFT calculations, the mechanism and pathway of BMI degradation by FeBDC-NH 2 /PDS are examined. The eco-toxicities of BMI degradation intermediates are researched to understand the impact of BMI degradation on the environment. These analyses show that the toxicities of BMI are effectively reduced by FeBDC-NH 2 -activated PDS under light irradiation and that the final derivatives of BMI produced during the degradation process are non-harmful in terms of both acute and chronic toxicities. [ABSTRACT FROM AUTHOR]

Assisted wet deposition methods to localize the active phase metal on the carrier surface and prevent atomic aggregation during conventional heat treatment are strongly preferred. Herein, single-atom cobalt catalysts (SA-Co-PCN) with different metal-central content were target-prepared using a combination of impregnation and secondary annealing on polymerized carbon nitride (PCN) through reticular confinement. Fitting the coordination configuration of the Co-N pathway within the first coordination shell according to quantitative EXAFS indicated that the ligancy of Co-N was 4. The removal efficiency of representative micropollutants in the SA-Co-PCN/PMS system achieved 100% within 15 min. The outstanding degradation properties of micropollutants were ascribed to the SA-Co-PCN boosts PMS to a 1O 2 -dominated system. Moreover, the effects of substituents on the degradation behavior and ecotoxicology of sulfonamides (SAs) in PMS-activated systems were investigated in depth. The combination of DFT theoretical calculations and LC-MS further confirmed that the similar electron-rich sites on the SAs molecules allowed for commonality in the degradation pathway. Both S-N bond and C-S bond fragments became the initial attack and cleavage sites in the series of SAs. Ecotoxicity predictions indicated that most intermediates of SAs exhibited lower acute and chronic toxicity, especially acute toxicity, than the parent compounds. Assisted wet deposition to localize the active phase metal on the carrier surface allows easy target formation of single-atom cobalt catalysts (SA-Co-PCN), which could boost PMS to a 1O 2 -dominated system for efficient oxidation of typical micropollutants. The degradation behavior and ecotoxicology of sulfonamides in the SA-Co-PCN/PMS system were investigated in depth, revealing that most intermediates of sulfonamides exhibited lower acute and chronic toxicity, especially acute toxicity, than the parent compounds. This work provides a strategy for the development of facilely prepared single-atom catalysts and contributes to the development and application potential of PMS advanced oxidation technology for water pollution control. [Display omitted] • Targeted preparation of SA-Co-PCN can activate PMS efficiently. • PCN improved performance relatively less with initial Co atom addition above 8 wt%. • The K obs of SAs were SDZ, SIX, SMT and SMX in descending order. • Both S-N bond and C-S bond cleavage were the commonalities of SAs degradation pathway. • The toxicity of SAs degradation products was significantly reduced. [ABSTRACT FROM AUTHOR]

Pyriclobenzuron 1 1 PBU – pyriclobenzuron. (PBU) is a novel molluscicide developed to control Pomacea canaliculate , and little information on its environmental fate has been published. In this study, the photolysis of PBU in an aqueous environment was simulated using a xenon lamp. Results showed that the photolysis of PBU in water followed first-order kinetics, exhibiting a t 0.5 of 95.1 h and 83.6 h in Milli-Q water and river water, respectively. Two main photolysis products 2 2 PPs – photolysis products. (PPs) were detected by HPLC-UV and identified by UPLC-Q/TOF MS, which were formed via the hydroxylation and photocatalytic hydro-dehalogenation of PBU, respectively. The initial relative abundance of photolysis product 1 3 3 PP-1 – photolysis product 1. (PP-1) in Milli-Q water was 1.55 times higher than that in river water. PP-1 was detected at 26.5 % and 76.8 % of the maximum relative abundance in the river water and Milli-Q water after 720 h, respectively. Photolysis product 2 4 4 PP-2 – photolysis product 2. (PP-2) was stable in water because of its weak hydrophilicity. The PP-2 detected after 720 h in Milli-Q water and river water was 93.7 % and 93.5 % of the maximum relative abundance, respectively. Finally, ECOSAR software was used to evaluate the acute aquatic toxicity of PBU and its PPs, revealing that the PPs had lower toxicity levels to non-target aquatic organisms. [Display omitted] • Photolysis t 0.5 values of PBU in two aqueous environments were 95.1 h and 83.6 h. • The photolysis pathways of PBU were hydroxylation and hydro-dehalogenation. • PP-2 was more stable than PP-1 in aqueous environments. • ECOSAR predicted that aquatic toxicity of PPs was lower than that of PBU. [ABSTRACT FROM AUTHOR]

Empirical and in silico data on the aquatic ecotoxicology of 2697 organic chemicals were collected in order to compile a dataset for assessing the predictive power of current Quantitative Structure Activity Relationship (QSAR) models and software platforms. This document presents the dataset and the data pipeline for its creation. Empirical data were collected from the US EPA ECOTOX Knowledgebase (ECOTOX) and the EFSA (European Food Safety Authority) report "Completion of data entry of pesticide ecotoxicology Tier 1 study endpoints in a XML schema - database". Only data for OECD recommended algae, daphnia and fish species were retained. QSAR toxicity predictions were calculated for each chemical and each of six endpoints using ECOSAR, VEGA and the Toxicity Estimation Software Tool (T.E.S.T.) platforms. Finally, the dataset was amended with SMILES, InChIKey, pKa and logP collected from webchem and PubChem., (© 2023 The Authors.)

Bioconcentration factors (BCFs) are markers of chemical substance accumulation in organisms, and they play a significant role in determining the environmental risk of various chemicals. Experiments to obtain BCFs are expensive and time-consuming; therefore, it is better to estimate BCF early in the chemical development process. The current research aims to evaluate the ecotoxicity potential of 122 pharmaceuticals and identify possible important structural attributes using BCF as the determining feature against a group of fish species. We have calculated the theoretical 2D descriptors from the OCHEM platform and SiRMS descriptor calculating software. The regression-based quantitative structure–property relationship (QSPR) modeling was used to identify the chemical features responsible for acute fish bioconcentration. Multiple models with the "intelligent consensus" algorithm were employed for the regression-based approach improving the predictive ability of the models. To ensure the robustness and interpretability of the developed models, rigorous validation was performed employing various statistical internal and external validation metrics. From the developed models, it can be specified that the presence of large lipophilic and electronegative moieties greatly enhances the bioaccumulative potential of pharmaceuticals, whereas the hydrophilic characteristics have shown a negative impact on BCF. Furthermore, the developed models were employed to screen the DrugBank database (https://go.drugbank.com/) for assessing the BCF properties of the entire database. The evidence acquired from the modeled descriptors might be used for aquatic risk assessment in the future, with the added benefit of providing an early caution of their probable negative impact on aquatic ecosystems for regulatory purposes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Red mud was used as an iron precursor for preparation of Fe0-biochar (RMIS 1:1). • Efficient removal of sulfadiazine (SDZ) was achieved by RMIS 1:1 /PDS system. • The intermediates of SDZ in RMIS 1:1 /PDS system have less eco-toxicity. • RMIS 1:1 /PDS was able to treat practical pharmaceutical wastewater. • RMIS 1:1 /PDS was more cost-effective than other advanced oxidation processes. Zerovalent iron (Fe0)-based biochar (Fe0-BC) has attracted wide attention in activating persulfate to eliminate antibiotics. In this study, the waste red mud (RM) was successfully used as an iron precursor to prepare Fe0-BC (RMIS 1:1) via co-pyrolysis strategy, which was confirmed with remarkable capacity in peroxydisulfate (PDS) activation. The removal efficiency of sulfadiazine (SDZ) was 99.7% in RMIS 1:1 /PDS system in 20 min, with k obs of 0.3001 min−1. Both free radicals (SO 4 −, OH, and O 2 −) and non-free radicals (1O 2) were responsible for SDZ degradation, in which the SO 4 − and O 2 − played the dominant roles. Four SDZ degradation pathways were provided according to the intermediates identified by Q-TOF-MS. Furthermore, the ECOSAR prediction implied that the intermediates have less eco-toxicity than SDZ. Compared with PDS concentration and RMIS 1:1 dosage, the initial SDZ concentration had stronger effect on its degradation. Co-existed Cl− slightly improved SDZ degradation rate, while other anions (NO 3 –/SO 4 2−/HCO 3 –/CO 3 2–) and humic acid exhibited different levels of inhibition on SDZ removal. Moreover, RMIS 1:1 /PDS maintained acceptable degradation ability for practical pharmaceutical wastewater. The electrical energy per mass of SDZ was about 2.24 kWh/(g·SDZ) by RMIS 1:1 /PDS, lower than that produced in any other advanced oxidation processes that have been reported so far. In summary, this study reported a green strategy for Fe0-BC preparation from RM, which was valuable for both waste resource recycling and environmental remediation. [ABSTRACT FROM AUTHOR]

Public health is a major concern globally, owing to the presence of industrial dyes in the effluent. Nanoparticles with green synthesis are an enthralling research field with various applications. This study deals with investigating the photocatalytic potential of Fe-oxide nanoparticles (FeO-NPs) for the degradation of methylene blue dye and their potential biomedical investigations. Biosynthesis using Anthemis tomentosa flower extract showed to be an effective method for the synthesis of FeO-NPs. The freshly prepared FeO-NPs were characterized through UV/Vis spectroscopy showing clear peak at 318 nm. The prepared FeO-NPs were of smaller size and spherical shape having large surface area and porosity with no aggregations. The FeO-NPs were characterized using XRD, FTIR, HRTEM, SEM and EDX. The HRTEM results showed that the particle size of FeO-NPs was 60–90 nm. The antimicrobial properties of FeO-NPs were investigated against two bacterial Staphylococcus aureus 13 (±0.8) and Klebsiella pneumoniae 6(±0.6) and three fungal species Aspergillus Niger, Aspergillus flavus, and Aspergillus fumigatus exhibiting a maximum reduction of 57% 47% and 50%, respectively. Moreover, FeO-NPs exhibited high antioxidant properties evaluated against ascorbic acid. Overall, this study showed high photocatalytic, antimicrobial, and antioxidant properties of FeO-NPs owing to their small size and large surface area. However, the ecotoxicity study of methylene blue degradation products showed potential toxicity to aquatic organisms. • Biosynthesis of FeNanoparticles. • Characterizations of FeONPs. • Photocatalytic behavior of FeONPs. • Biomedical screening of FeONPs. • ECOSAR study of Methylene Blue. [ABSTRACT FROM AUTHOR]

The metal–organic frameworks (MOF)-based photocatalytic treatment of lincomycin employing Basolite F300 as catalyst in the presence of two oxidants (H 2 O 2 , S 2 O 8 2-) was investigated. Both processes led to the elimination of lincomycin within 120 min of treatment. The oxidant's addition has an enhancing effect on the process, possibly from heterogeneous Fenton-type reactions. The concentration effect (0–300 mg/L) of the oxidants was explored, and the optimum amount achieving the highest degradation rate proved to be 100 mg/L for both oxidants. In total, 39 transformation products were identified out of which 24 are proposed for the first time, while the main transformation pathways were hydroxylation, S-oxidation, desulfurization, pyranose ring opening, and cleavage of the C-N bond. For an integrated evaluation of the process, toxicity measurements of the treated solution were performed by a bioassay using D.Magna. Toxicity was more pronounced in the first stages of treatment, implying synergistic effects between the formed intermediate transformation products (TPs), while notable toxicity reduction was achieved at the end of the process. Ecological structure-activity relationship (ECOSAR) predictions revealed the formation of many non-toxic TPs with hydroxylation being the key to the detoxification of the formed compounds. [Display omitted] • Complete degradation of lincomycin within 120 min of treatment. • Oxidant's addition plays a dominant role leading to Fenton-type reactions. • Thirty-nine transformation products are identified. • A notable toxicity reduction is achieved at the end of the process. • ECOSAR predictions reveal the formation of many non-toxic TPs. [ABSTRACT FROM AUTHOR]

Coal tar wastewater is hard to degrade by traditional methods because of its toxic pollutant constituents and high concentration of aromatic hydrocarbons, especially phenolic substances. A new type of hydrophobic benzacetone modified PbO 2 anode (BA-PbO 2 electrodes) was used for the electrocatalytic treatment of coal tar wastewater in a continuous cycle reactor. The surface morphology, structure, valences of elements, hydrophobicity, hydroxyl radical (·OH) produced capacity, electrochemical properties and stability of BA-PbO 2 electrodes were characterized by SEM (scanning electron microscopy), XRD (X-ray diffraction), XPS (X-ray photoelectron spectroscopy), contact angle, a fluorescence probe test, an electrochemical workstation and accelerated life test, respectively. The BA-PbO 2 electrodes exhibited a compact structure and finely dispersed crystallize size of 4.6 nm. The optimum degradation conditions of coal tar wastewater were as follows: current density of 90 mA cm−2, electrode gap of 1 cm and temperature at 25 °C with flow velocity of 80 L h−1. The chemical oxygen demand (COD) removal efficiency reached 92.39% after 240 min of degradation under the optimized conditions and the after-treatment COD value was 379.51 mg L−1 which was lower than the centralized emission standard (less than 400 mg L−1). These findings demonstrated the feasibility and efficiency of electrocatalytically degrading coal tar wastewater by BA-PbO 2 electrodes. The possible mechanism and pathway for phenol a specific pollutant in coal tar wastewater were investigated by quantum chemistry calculations (Multiwfn) and gas chromatography-mass spectrometry (GC-MS). The toxicity of each intermediate was predicted by the ECOSAR program. [Display omitted] • A novel hydrophobic PbO 2 electrode was fabricated and characterized. • BA-PbO 2 electrode effectively remove phenol from actual coal tar wastewater. • Degradation pathways and ecotoxicity were revealed systematically. • Fukui functions and dual descriptor were calculated to predict reactive sites. • A novel continuous cycle reactor was used in the degradation system. [ABSTRACT FROM AUTHOR]