Assessment of chlorine and hydrogen peroxide on airborne bacteria: Disinfection efficiency and induction of antibiotic resistance.

Airborne pathogens severely threaten public health worldwide. Air disinfection is essential to ensure public health. However, excessive use of disinfectants may endanger environmental and ecological security due to the residual disinfectants and their by-products. This study systematically evaluated disinfection efficiency, induction of multidrug resistance, and the underlying mechanisms of disinfectants (NaClO and H2O2) on airborne bacteria. The results showed that airborne bacteria were effectively inactivated by atomized NaClO (>160 µg/L) and H2O2 (>320 µg/L) after 15 min. However, some bacteria still survived after disinfection by atomized NaClO (0-80 µg/L) and H2O2 (0-160 µg/L), and they exhibited significant increases in antibiotic resistance. The whole-genome sequencing of the resistant bacteria revealed distinct mutations that were responsible for both antibiotic resistance and virulence. This study also provided evidences and insights into possible mechanisms underlying the induction of antibiotic resistance by air disinfection, which involved intracellular reactive oxygen species formation, oxidative stress responses, alterations in bacterial membranes, activation of efflux pumps, and the thickening of biofilms. The present results also shed light on the role of air disinfection in inducing antibiotic resistance, which could be a crucial factor contributing to the global spread of antibiotic resistance through the air.

Highly efficient treatment of tetracycline using coupled electro-Fenton and electrocoagulation process: Mechanism and toxicity assessment.

In this study, a novel carbon fiber brush (CFB) electrode was designed using carbon fiber filaments and conductive metals. It was used as the cathode to construct an efficient coupled electro-Fenton and electrocoagulation (EF-EC) process for tetracycline (TC) treatment. An optimal 97.9% removal rate of 10 mg L-1 TC was achieved within 20 min. The coupled process is less pH-dependent and more effective in treating TC compared to the traditional individual electro-Fenton (EF) or electrocoagulation (EC) process, achieving efficient TC removal under neutral pH conditions. The removal rate of 10 mg L-1 TC consistently remained above 92% at 20 min after ten cycle experiments using the same electrodes in a Fe-CFB system (92.7-97.9%), indicating excellent reusability and stability of the CFB cathode. Mechanism analysis showed both EF and EC processes were involved in the system. Radicals (such as •OH and SO4-•) generated by EF contributed to the degradation of TC, yielding nine intermediates. Coagulants (such as Fe(OH)3) generated by EC contributed to the removal of TC. Toxicity prediction results indicated that over half of the nine intermediates exhibited lower biotoxicity compared to TC. This study provides a feasible alternative cathode for the efficient treatment of TC using EF-EC process.

Removal enhancement of persistent basic fuchsin dye from wastewater using an eco-friendly, cost-effective Fenton process with sodium percarbonate and waste iron catalyst.

In this comprehensive investigation, we evaluate the efficacy of the Fenton process in degrading basic fuchsin (BF), a resistant dye. Our primary focus is on the utilization of readily available, environmentally benign, and cost-effective reagents for the degradation process. Furthermore, we delve into various operational parameters, including the quantity of sodium percarbonate (SPC), pH levels, and the dimensions of waste iron bars, to optimize the treatment efficiency. In the course of our research, we employed an initial SPC concentration of 0.5 mM, a pH level of 3, a waste iron bar measuring 3.5 cm in length and 0.4 cm in diameter, and a processing time of 10 min. Our findings reveal the successful elimination of the BF dye, even when subjected to treatment with diverse salts and surfactants under elevated temperatures and acidic conditions (pH below 3). This underscores the robustness of the Fenton process in purifying wastewater contaminated with dye compounds. The outcomes of our study not only demonstrate the efficiency of the Fenton process but highlight its adaptability to address dye contamination challenges across various industries. Critically, this research pioneers the application of waste iron bars as a source of iron in the Fenton reaction, introducing a novel, sustainable approach that enhances the environmental and economic viability of the process. This innovative use of recycled materials as catalysts represents a significant advancement in sustainable chemical engineering practices.

Exploring Therapeutic Potential of Catalase: Strategies in Disease Prevention and Management.

The antioxidant defense mechanisms play a critical role in mitigating the deleterious effects of reactive oxygen species (ROS). Catalase stands out as a paramount enzymatic antioxidant. It efficiently catalyzes the decomposition of hydrogen peroxide (H2O2) into water and oxygen, a potentially harmful byproduct of cellular metabolism. This reaction detoxifies H2O2 and prevents oxidative damage. Catalase has been extensively studied as a therapeutic antioxidant. Its applications range from direct supplementation in conditions characterized by oxidative stress to gene therapy approaches to enhance endogenous catalase activity. The enzyme's stability, bioavailability, and the specificity of its delivery to target tissues are significant hurdles. Furthermore, studies employing conventional catalase formulations often face issues related to enzyme purity, activity, and longevity in the biological milieu. Addressing these challenges necessitates rigorous scientific inquiry and well-designed clinical trials. Such trials must be underpinned by sound experimental designs, incorporating advanced catalase formulations or novel delivery systems that can overcome existing limitations. Enhancing catalase's stability, specificity, and longevity in vivo could unlock its full therapeutic potential. It is necessary to understand the role of catalase in disease-specific contexts, paving the way for precision antioxidant therapy that could significantly impact the treatment of diseases associated with oxidative stress.

Hemin as a Molecular Probe for Nitric Oxide Detection in Physiological Solutions: Experimental and Theoretical Assessment.

Given its pivotal role in modulating various pathological processes, precise measurement of nitric oxide (●NO) levels in physiological solutions is imperative. The key techniques include the ozone-based chemiluminescence (CL) reactions, amperometric ●NO sensing, and Griess assay, each with its advantages and drawbacks. In this study, a hemin/H2O2/luminol CL reaction was employed for accurately detecting ●NO in diverse solutions. We investigated how the luminescence kinetics was influenced by ●NO from two donors, nitrite and peroxynitrite, while also assessing the impact of culture medium components and reactive species quenchers. Furthermore, we experimentally and theoretically explored the mechanism of hemin oxidation responsible for the initiation of light generation. Although both hemin and ●NO enhanced the H2O2/luminol-based luminescence reactions with distinct kinetics, hemin's interference with ●NO/peroxynitrite- modulated their individual effects. Leveraging the propagated signal due to hemin, the ●NO levels in solution were estimated, observing parallel changes to those detected via amperometric detection in response to varying concentrations of the ●NO-donor. The examined reactions aid in comprehending the mechanism of ●NO/hemin/H2O2/luminol interactions and how these can be used for detecting ●NO in solution with minimal sample size demands. Moreover, the selectivity across different solutions can be improved by incorporating certain quenchers for reactive species into the reaction.

C-Phycocyanin Attenuates Noise-Induced Cochlear Synaptopathy via the Inhibition of Oxidative Stress and Intercellular Adhesion Molecule-1 in the Cochlea.

The synapses between inner hair cells (IHCs) and spiral ganglion neurons (SGNs) are the most vulnerable structures in the noise-exposed cochlea. Cochlear synaptopathy results from the disruption of these synapses following noise exposure and is considered the main cause of poor speech understanding in noisy environments, even when audiogram results are normal. Cochlear synaptopathy leads to the degeneration of SGNs if damaged IHC-SGN synapses are not promptly recovered. Oxidative stress plays a central role in the pathogenesis of cochlear synaptopathy. C-Phycocyanin (C-PC) has antioxidant and anti-inflammatory activities and is widely utilized in the food and drug industry. However, the effect of the C-PC on noise-induced cochlear damage is unknown. We first investigated the therapeutic effect of C-PC on noise-induced cochlear synaptopathy. In vitro experiments revealed that C-PC reduced the H2O2-induced generation of reactive oxygen species in HEI-OC1 auditory cells. H2O2-induced cytotoxicity in HEI-OC1 cells was reduced with C-PC treatment. After white noise exposure for 3 h at a sound pressure of 118 dB, the guinea pigs intratympanically administered 5 µg/mL C-PC exhibited greater wave I amplitudes in the auditory brainstem response, more IHC synaptic ribbons and more IHC-SGN synapses according to microscopic analysis than the saline-treated guinea pigs. Furthermore, the group treated with C-PC had less intense 4-hydroxynonenal and intercellular adhesion molecule-1 staining in the cochlea compared with the saline group. Our results suggest that C-PC improves cochlear synaptopathy by inhibiting noise-induced oxidative stress and the inflammatory response in the cochlea.

Unveiling the potential of machine learning in cost-effective degradation of pharmaceutically active compounds: A stirred photo-reactor study.

In this study, neural networks and support vector regression (SVR) were employed to predict the degradation over three pharmaceutically active compounds (PhACs): Ibuprofen (IBP), diclofenac (DCF), and caffeine (CAF) within a stirred reactor featuring a flotation cell with two non-concentric ultraviolet lamps. A total of 438 datapoints were collected from published works and distributed into 70% training and 30% test datasets while cross-validation was utilized to assess the training reliability. The models incorporated 15 input variables concerning reaction kinetics, molecular properties, hydrodynamic information, presence of radiation, and catalytic properties. It was observed that the Support Vector Regression (SVR) presented a poor performance as the ε hyperparameter ignored large error over low concentration levels. Meanwhile, the Artificial Neural Networks (ANN) model was able to provide rough estimations on the expected degradation of the pollutants without requiring information regarding reaction rate constants. The multi-objective optimization analysis suggested a leading role due to ozone kinetic for a rapid degradation of the contaminants and most of the results required intensification with hydrogen peroxide and Fenton process. Although both models were affected by accuracy limitations, this work provided a lightweight model to evaluate different Advanced Oxidation Processes (AOPs) by providing general information regarding the process operational conditions as well as know molecular and catalytic properties.

A life cycle assessment of the laboratory-scale oxidative liquefaction as the chemical recycling method of the end-of-life wind turbine blades.

According to the latest reports, estimated values of 50,000-66 000 t of end-of-life wind turbine blades (WTB) are expected to be decommissioned in Europe in 2025-2030, posing a significant threat from the environmental and waste management perspectives. This study aims to present the preliminary Life Cycle Assessment (LCA) with sensitivity and uncertainty analysis of the lab-scale oxidative liquefaction process of the WTB, as the original method to recover the high-quality glass fibers with simultaneous production of the secondary chemicals: phenols, ketones, acids, and fatty acids, from the oxidation of the epoxy resin from the polymer matrix. The LCA is based on the experimental results of the oxidative liquefaction process carried out on a laboratory scale using a Parr 500 ml batch reactor, at two different conditions sets for the functional unit (FU) of 1 kg of treated WTB. Each of the analyzed scenarios resulted in higher impact indicators compared to the landfilling. The highest quality fibers were obtained at 350 °C and 40 wt % H2O2 content resulted in 5.52 ± 1.20 kgCO2 eq Climate change impact and 97.8 ± 20.6 MJ of Resource use, fossil per kg of recycled WTB. The lowest quality fiber recovered in char, yet well separated from the matrix obtained at 250 °C and the lowest H2O2 content resulted in 0.0953 ± 0.487 kgCO2 eq Climate change impact and 8.84 ± 7.90 MJ of Resource use, fossil per kg of recycled WTB. The hot spot and sensitivity analysis indicated, that the oxidizer for the process - hydrogen peroxide, when acquired as a shelf product causes a significant burden on the whole process, with sensitivity ratios on the total impact indicators varying across the categories from 0.56 to 0.99. Substitution of H2O2 with theoretical 0-input oxidizer allowed to significantly lower environmental load of the recycling process, which in all of the analyzed scenarios presented environmental benefits compared to landfilling with recovery of the glass fiber and secondary chemicals.

Dual-Activated H2O2-Responsive AIE Probes for Oocyte Quality Assessment.

Nonobstructive azoospermia (NOA) is an important cause of infertility, and intracytoplasmic sperm injection (ICSI) is the mainstay of treatment for these patients. In cases where a sufficient number of sperm (usually 1-2) is not available, the selection of oocytes for ICSI is a difficult problem that must be solved. Here, we constructed a dual-activated oxidative stress-responsive AIE probe, b-PyTPA. The strong donor-acceptor configuration of b-PyTPA leads to twisted intramolecular charge transfer (TICT) effect that quenches the fluorescence of the probe, however, H2O2 would specifically remove the boronatebenzyl unit and release a much weaker acceptor, which inhibits TICT and restores the fluorescence. In addition, the presence of a pyridine salt makes b-PyTPA more hydrophilic, whereas removal of the pyridine salt increases the hydrophobicity of PyTPA, which triggers aggregation and further enhances fluorescence. Thus, the higher the intracellular level of oxidative stress, the stronger the fluorescence. In vitro, this dual-activated fluorescent probe is capable of accurately detecting senescent cells (high oxidative stress). More importantly, b-PyTPA was able to characterize senescent oocytes, as assessed by the level of oxidative stress. It is also possible to identify high quality oocytes from those obtained for subsequent ICSI. In conclusion, this dual-activated oxidative stress-assessment probe enables the quality assessment of oocytes and has potential application in ICSI.

Investigation of the removal of diclofop methyl herbicide by peroxy electrocoagulation process and kinetic and cost analysis.

Pesticides containing chlorine, which are released during agricultural activities, are chemical substances that mix with surface and underground waters and have toxic, carcinogenic, and mutagenic effects on the entire living ecosystem. Due to their chemically stable structure, conventional water and wastewater treatment techniques such as coagulation, flocculation, and biological oxidation do not entirely remove these chemical substances. Therefore, before releasing them into the environmental receptor, these chemical substances must be transformed into harmless products or mineralized through advanced oxidation processes. When we look at the literature, there are not many studies on methods of removing diclofop methyl from aquatic media. Our study on the removal of diclofop methyl herbicide from aquatic media using the peroxy electrocoagulation method will provide the first information on this subject in the literature. In addition, this treatment method will contribute significantly to filling an important gap in the literature as an innovative approach for diclofop methyl removal. Moreover, peroxy electrocoagulation, which produces less sludge, provides treatment in a short time, and is economical, has been determined to be an advantageous process. The effects of conductivity, pH, H2O2 concentration, current, and time parameters on the removal of diclofop methyl were investigated using a GC-MS instrument. Kinetics, energy consumption, and cost calculations were also made. Under the optimum conditions determined (pH = 5, H2O2 = 500 mg/L, NaCl = 0.75 g/L, current density = 2.66 mA/cm2), the peroxydic electrocoagulation process resulted in a diclofop methyl removal efficiency of 79.2% after a 25-min reaction. When the experimental results were analyzed, it was found that the results fitted the pseudo-second-order kinetic model.

Z-scheme heterojunction composed of Fe-doped g-C3N4 and Bi2MoO6 for photo-fenton degradation of antibiotics over a wide pH range: Activity and toxicity assessment.

In photo-Fenton technology, the narrower pH range limits its practical application for antibiotic wastewater remediation. Therefore, in this study, a Z-scheme heterojunction photo-Fenton catalyst was constructed by Fe-doped graphite-phase carbon nitride in combination with bismuth molybdate for the degradation of typical antibiotics. Fe doping can shorten the band gap and increase visible-light absorption. Simultaneously, the constructed Z-scheme heterojunction provides a better charge transfer pathway for the photo-Fenton reaction. Within 30 min, Fe3CN/BMO-3 removed 95.54% of tetracycline hydrochloride (TC), and its remarkable performance was the higher Fe3+/Fe2+ conversion efficiency through the decomposition of H2O2. The Fe3CN/BMO-3 catalyst showed remarkable photo-Fenton degradation performance in a wide pH range (3.0-11.0), and it also had good stability in the treatment of TC wastewater. Furthermore, the order of action of the active species was h+ > ·O2- > 1O2 > ·OH, and the toxicity assessment suggested that Fe3CN/BMO-3 was effective in reducing the biotoxicity of TC. The catalyst proved to be an economically feasible and applicable material for antibiotic photo-Fenton degradation, and this study provides another perspective on the application of elemental doping and constructed heterojunction photo-Fenton technology for antibiotic water environmental remediation.

Safety Assessment of Hydrogen Peroxide as Used in Cosmetics.

The Expert Panel for Cosmetic Ingredient Safety (Panel) assessed the safety of Hydrogen Peroxide for use in cosmetics. This ingredient is reported to function in cosmetics as an antimicrobial agent, cosmetic biocide, oral health care agent, and oxidizing agent. The Panel reviewed the data relevant to the safety of this ingredient and concluded that Hydrogen Peroxide is safe in cosmetics in the present practices of use and concentration described in this safety assessment.

Assessment of color changes and adverse effects of over-the-counter bleaching protocols: a systematic review and network meta-analysis.

OBJECTIVES: To assess color change efficacy and the adverse effects of varied over-the-counter (OTC) bleaching protocols. METHODOLOGY: The study included randomized clinical trials evaluating color changes from OTC bleaching agents. Nine databases were searched, including the partial capture of the grey literature. The RoB2 tool analyzed the individual risk of bias in the studies. Frequentist network meta-analyses compared treatments through common comparators (∆Eab* and ∆SGU color changes, and tooth sensitivity), integrating direct and indirect estimates and using the mean and risk differences as effect measures with respective 95% confidence intervals. The GRADE approach assessed the certainty of the evidence. RESULTS: Overall, 37 remaining studies constituted the qualitative analysis, and ten composed the meta-analyses. The total sample included 1,932 individuals. ∆Eab* was significantly higher in groups 6% hydrogen peroxide (HP) strips (≥ 14 h). ∆SGU was significantly higher in groups at-home 10% carbamide peroxide (CP) (≥ 14 h), followed by 6% HP strips (≥ 14 h) and 3% HP strips (≥ 14 h). At-home 10% CP (7-13 h) and placebo showed lower risks of tooth sensitivity without significant differences between these treatments. CONCLUSION: Considering the low level of evidence, OTC products presented satisfactory short-term effects on tooth bleaching compared to the placebo, with little to no impact on dentin hypersensitivity and gingival irritation. CLINICAL RELEVANCE: OTC products are proving to be practical alternatives for tooth whitening. However, patients should be advised about the possible risks of carrying out such procedures without professional supervision.

Nitrogen-doped metal-free granular activated carbons as economical and easily separable catalysts for peroxymonosulfate and hydrogen peroxide activation to degrade bisphenol A.

The fabrication of low-cost, highly efficient, environmentally friendly, and easily separable metal-free heterogeneous catalysts for environmental remediation remains a challenge. In this study, granular nitrogen-doped highly developed porous carbons with a particle size of 0.25-0.30 mm were prepared by preoxidation and subsequent NH3 modification of a commercially available coconut-based activated carbon, and used to activate peroxymonosulphate (KHSO5) or hydrogen peroxide (H2O2) to degrade bisphenol A (BPA). The nitrogen-doped carbon (ACON-950) prepared by NH3 modification at 950 °C, with the addition of only 0.15 g/L could remove 100% of 50 mg/L BPA in 150 min, and more than 90% of the removed BPA was due to degradation. The removal rates of total organic carbon of ACON-950/KHSO5 and ACON-950/H2O2 systems reached 60.4% and 66.2% respectively, indicating the excellent catalytic activity of ACON-950. The reaction rate constant was significantly positively correlated with the absolute content of pyridinic N (N-6) and graphitic N (N-Q) and negatively and weakly positively correlated with pyrrolic N (N-5) and defects. Quenching experiments combined with electron paramagnetic resonance demonstrated that singlet oxygen was the dominant reactive oxidative species for BPA degradation. ACON-950 was characterized before and after the degradation reaction using N2 adsorption-desorption analyzer, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results confirmed the prominent contribution of both the N-6 and N-Q to the catalytic performance of nitrogen-doped carbons. The reusability of ACON-950 and its application in actual water bodies further demonstrated its remarkable potential for the remediation of organic pollutants in wastewater.

Assessment of microplastic contamination in some commercial fishes of the southern Caspian Sea and its potential risks.

This study examined the occurrence of microplastics (MPs) in the gastrointestinal tract (GIT) of 384 fishes classified into four species from 11 sites in 2022 from the southern part of the Caspian Sea. GITs of fishes were collected and digested in H2O2 and KOH at 45 °C for 72 h. After filtration, extracted MPs were observed under a stereomicroscope, and selected MP particles were identified using FTIR. Presence of MPs was 68.98% in the GIT of the investigated fish. The mean abundance of MPs was 5.9 ± 0.9 MPs/GIT in Rutilus kutum, 9.2 ± 1.2 MPs/GIT in Chelon auratus, 3.6 ± 0.7 MPs/GIT in Alosa braschnikowi, and 2.7 ± 0.5 MPs/GIT in Vimba vimba. The predominant form of MPs was fiber (58.21%), followed by fragment (34.77%). Black (34.4%), white (19.07%), and blue (14.58%) were the most frequently detected colors of MPs. Overall, 6 MP polymers were identified, dominantly polypropylene (42.86%), polystyrene (17.86%), and cellophane (14.28%). The western part of the Caspian Sea (mostly tourist spots and urban areas) showed more MP pollution in fish compared to the eastern part. Polymer hazard index (PHI) revealed alarming microplastic contamination in the southern Caspian Sea. The PHI value of the present study showed that PES (PHI = 8403.78) and PS (PHI = 535.80) were "Extreme danger" and "Danger" risk categories, respectively.

Assessment of essential and potentially toxic metals in raw cow milk from Mukaturi town, Oromia Regional State, Ethiopia.

Cow milk is a complete and highly nutritious source of food for humans. However, the quality of milk products has become a significant health concern for consumers, particularly infants and children, in many developing nations, including Ethiopia. The objective of this study was to determine the heavy metal levels in raw cow milk collected from dairy producers and collection centers in Mukaturi town, Ethiopia. Sixty raw cow milk samples (40.0 milk samples from dairy farms and 20.0 milk samples from collection centers) were randomly collected and digested using a mixture of nitric acid (HNO3), hydrogen peroxide (H2O2) and perchloric acid (HClO4) on a hot plate. The amounts of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in the milk samples were determined using inductively coupled plasma atomic emission spectroscopy (ICP-OES). The findings showed that the average concentrations of Pb (2.31 ± 0.127), Fe (0.566 ± 0.130), Ni (0.210 ± 0.0189), Cd (0.0372 ± 0.0230), Cr (0.369 ± 0.0162), and Co (0.225 ± 0.0150) in mgL-1 were higher than the allowable limits. This could pose a health risk to the public. However, the concentrations of Mn (0.044 ± 0.0369), Cu (0.195 ± 0.0450) and Zn (2.90 ± 0.0570) in mg L-1 were lower than or within the recommended limits and cannot pose any threat to consumers. The validity of the digestion processes was checked by the recovery test. The percentage recoveries of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn were found to be in the range of 80.7-122 %, which is within the acceptable range. Therefore, special attention should be given to the continuous monitoring of heavy metal levels in raw milk among dairy producers and collection centers to minimize economic losses and the risk to consumer safety.

Chitosan oligosaccharide improves intestinal homeostasis to achieve the protection for the epithelial barrier of female Drosophila melanogaster via regulating intestinal microflora.

Chitosan oligosaccharide (COS) is a new type of marine functional oligosaccharide with biological activities such as regulating intestinal microflora and improving intestinal immunity. In this study, female Drosophila melanogaster was used as a model organism to evaluate the effect of COS on intestinal injury by H2O2 induction, and its mechanism was explored through the analysis of intestinal homeostasis. The results showed that 0.25% of COS could effectively prolong the lifespan of stressed female D. melanogaster by increasing its antioxidant capacity and maintaining intestinal homeostasis, which included protecting the mechanical barrier, promoting the chemical barrier, and regulating the biological barrier by affecting its autophagy and the antioxidant signaling pathway. Additionally, the protective effect of COS on the intestinal barrier and homeostasis of D. melanogaster under oxidative stress status is directly related to its regulation of the intestinal microflora, which could decrease excessive autophagy and activate the antioxidant system to promote health. IMPORTANCE: The epithelial barrier plays an important role in the organism's health. Chitosan oligosaccharide (COS), a new potential prebiotic, exhibits excellent antioxidant capacity and anti-inflammatory effects. Our study elucidated the protective mechanisms of COS on the intestinal barrier of Drosophila melanogaster under oxidative stress, which could provide new insights into COS application in various industries, such as food, agriculture, and medicine.

Hexabromocyclododecane-induced reproductive toxicity in Brachionus plicatilis: Impacts and assessment.

Hexabromocyclododecane (HBCD), third-generation brominated flame retardants (BRFs), has aroused worldwide concern because of its wide application and potentially negative impacts on marine ecosystems, but an information gap still exists regarding marine low-trophic organisms. Brachionus plicatilis, the model marine zooplankton, was used in the present study, and its reproductive responses were used as the endpoint to indicate HBCD-induced toxicity. HBCD was suggested to be extremely highly toxic compounds regarding the 96 h-LC50 of 0.58 mg L-1. The sublethal exposure of HBCD injured the reproduction of B. plicatilis: The total number of offspring per female and the key population index calculated from the life table, including the intrinsic rate of population increase (rm) and net reproductive rate (R0), were significantly influenced in a concentration-dependent manner. The reproductive process was also altered, as indicated by the first spawning time, first hatching time and oocyst development time. At the same time, individual survival and growth (body length) were also negatively affected by HBCD. Reactive oxygen species (ROS) were suggested to be responsible for reproductive toxicity mainly because the total ROS contents as well as the main components of •OH and H2O2 greatly increased and resulted in the oxidative imbalance that presented as malondialdehyde (MDA) elevation. Simultaneous activation of the glutathione antioxidant system was accompanied by the apoptosis marker enzymes Caspase-3 and 9, as well as the correlation between ROS content, physiological alteration and cell apoptosis, providing further evidence for this. The integrated biomarker response (IBR) and adverse outcome pathway (AOP) showed that HBCD had a significant toxic effect on B. plicatilis near the concentration range of 96 h-LC50. The establishment of this concentration range will provide a reliable reference for future environmental concentration warning of HBCD in marine.

Highly efficient heterogeneous electro-Fenton reaction for tetracycline degradation by Fe-Ni LDH@ZIF-67 modified carbon cloth cathode: Mechanism and toxicity assessment.

In this work, a novel and efficient Fe-Ni LDH@ZIF-67 catalyst modified carbon cloth (CC) cathode was developed for tetracycline (TC) degradation in heterogeneous electro-Fenton (Hetero-EF) process. Compared to Fe-Ni LDH/CC (75.7%), TC degradation rate of Fe-Ni LDH@ZIF-67/CC cathode increased to 95.6% within 60 min. The synergistic effect of hetero-EF and anodic oxidation process accelerated electron transfer, the maximum H2O2 production of Fe-Ni LDH@ZIF-67/CC electrode reached 264 mg/L, improving utilization efficiency of H2O2. The cathode possessing a satisfied TC degradation performance over a wide pH (3-9). Free radical capture experiment revealed the collaboration of ·O2-, ·OH, and 1O2 play a significant role in TC degradation. The 5 cycles experiment and metal ion leaching experiment showed that the proposed Fe-Ni LDH@ZIF-67/CC has good recyclability and stability. In addition, the proposed Fe-Ni LDH@ZIF-67/CC cathode achieved satisfying performance in real water (tap water: 97.3%, lake water: 97.7%), demonstrating the possibility for practical application. TC degradation pathways were proposed by theory analysis and experimental results. The toxicity of TC intermediates was reduced by Hetero-EF degradation according to Toxicity Estimation Software Tool and Escherichia coli growth inhibition experiments. This work provides a novel modified cathode to improve removal efficiency of antibiotics in wastewater.

Real-Time Monitoring of Air Pollution Health Impacts Using Breath-Borne Gaseous Biomarkers from Rats.

Offline techniques are adopted for studying air pollution health impacts, thus failing to provide in situ observations. Here, we have demonstrated their real-time monitoring by online analyzing an array of gaseous biomarkers from rats' exhaled breath using an integrated exhaled breath array sensor (IEBAS) developed. The biomarkers include total volatile organic compounds (TVOC), CO2, CO, NO, H2S, H2O2, O2, and NH3. Specific breath-borne VOCs were also analyzed by a gas chromatography-ion mobility spectrometer (GC-IMS). After real-life ambient air pollution exposures (2 h), the pollution levels of PM2.5 and O3 were both found to significantly affect the relative levels of multiple gaseous biomarkers in rats' breath. Eleven biomarkers, especially NO, H2S, and 1-propanol, were detected as significantly correlated with PM2.5 concentration, while heptanal was shown to be significantly correlated with O3. Likewise, significant changes were also detected in multiple breath-borne biomarkers from rats under lab-controlled O3 exposures with levels of 150, 300, and 1000 µg/m3 (2 h), compared to synthetic air exposure. Importantly, heptanal was experimentally confirmed as a reliable biomarker for O3 exposure, with a notable dose-response relationship. In contrast, conventional biomarkers of inflammation and oxidative stress in rat sera exhibited insignificant differences after the 2 h exposures. The results imply that breath-borne gaseous biomarkers can serve as an early and sensitive indicator for ambient pollutant exposure. This work pioneered a new research paradigm for online monitoring of air pollution health impacts while obtaining important candidate biomarker information for PM2.5 and O3 exposures.