Frontiers of Environmental Science & Engineering最新文献

The global spread of viruses can lead to the release of large amounts of disinfectants or antiviral drugs into the water environment. The resulting disinfection byproducts (DBPs) and residual antiviral drugs, acting as genotoxic substances or their precursors, may pose risks to aquatic animals and drinking water sources; however, to date, no studies have analyzed the changes in genotoxicity in the Yangtze River before and after the epidemic. In the present study, water and sediment samples from the Yangtze River were collected during different seasons, just before and after the outbreak of COVID-19, and were assessed using the SOS/umu test (with and without liver S9). The results indicated that water samples exhibited more pronounced genotoxicity than did sediments, with direct genotoxicity being the primary factor. Additionally, there were significant regional differences, with notably greater genotoxicity observed in the upper Yangtze River than in the lower reaches before the COVID-19 epidemic. However, this trend was reversed six to ten months later, suggesting the accumulation of DBPs or antiviral drugs after the COVID-19 pandemic. Moreover, the risk quotient indicated that 65% of the water samples posed a high risk for Paramecium caudatum, whereas 71% of the samples posed a medium risk for Danio rerio, thereby representing a potential threat to the ecological security of the Yangtze River. In conclusion, this study, at the basin scale, revealed the impacts of COVID-19 on the Yangtze River, highlighting the need to prevent DBPs and pharmaceutical pollution during similar events in the future.

Glucocorticoids, which are one of the most extensively used steroid hormones, are typical endocrine disruptors. In recent years, glucocorticoids have been widely detected in surface waters such as rivers and lakes, but there are relatively few studies focusing on their ecological risk assessment. In this study, the pollution characteristics of seven glucocorticoids were studied in the Jiangsu section of the Yangtze River Basin, and ecological risk assessments were performed using the risk quotient method. The results showed that seven glucocorticoids were detected at different levels at eight sampling sites. Among these glucocorticoids, prednisone had the highest value of 238.27 ng/L in the wet season, with pollution levels significantly higher than those reported in other areas. The ecological risk evaluation showed that prednisone, prednisolone, dexamethasone, and hydrocortisone acetate all had risk quotient values greater than 1 in the studied water environment, posing a high ecological risk. This study provides a scientific foundation for the in-depth study of the pollution characteristics and ecological risk of glucocorticoids in water bodies in the Jiangsu section of the Yangtze River Basin.

Most antibiotics contain ionizable groups that undergo acid-base dissociation giving rise to diverse dissociated forms in aquatic systems depending on the pH of the system. In sunlit surface waters, photochemical transformation plays a crucial role in determining the fate of antibiotics. This study presents a comprehensive examination of the photo-transformation degradation kinetics, pathways and photoinduced toxicity of three widely detected tetracyclines (TCs): tetracycline (TC), oxytetracycline (OTC), and chlortetracycline (CTC). Under simulated sunlight (λ > 290 nm), their apparent photolysis followed pseudo-first-order kinetics, with rate constants significantly increasing from H₂TCs⁰ to TCs²⁻. Through competition kinetic experiments and matrix calculations, it was found that the anions HTCs⁻ or TCs²⁻ (pH ∼ 8–10) were more reactive toward hydroxyl radicals (•OH), while TCs²⁻ (pH ∼ 10) reacted the fastest with singlet oxygen (¹O₂). Considering the dissociated species, the total environmental photo-transformation half-lives of TCs were determined, revealing a strong dependence on the water pH and seasonal variation in sunlight. Generally, apparent photolysis was the dominant photochemical process, followed by ¹O₂ and •OH oxidation. Different transformation pathways for the three reactions were determined based on the key photoproducts identified using HPLC-MS/MS. Toxicity tests and ECOSAR software calculations confirmed that the intermediates produced by the •OH and ¹O₂ photo-oxidation processes were more toxic than the parent compounds. These findings significantly enhance our understanding of the complex photochemical fate and associated risks of TCs in aqueous environments.

Current microbial control strategies face challenges in keeping up with the escalation of microbial problems due to the presence of biofilms. Therefore, there is an urgent need to develop effective and robust strategies to control problematic biofilms in water treatment and reuse systems. Nanozymes, which have intrinsic biocatalytic activity and broad antibacterial spectra, hold promise for controlling resilient biofilms. This review summarizes the milestones of nanozyme studies and their applications as antibiofilm agents. The mechanisms behind the antibacterial, quorum quenching, and depolymerizing properties of nanozymes with different enzyme activities are discussed. Notably, the surface and composition of nanozymes are crucial for their efficacy in biofilm control; thus, rationally designed nanozymes can increase their effectiveness. Additionally, the challenges of nanozymes as antibiofilm agents in realistic scenarios are investigated along with proposed strategies to overcome these challenges. Prospects of nanozyme-based biofilm control, such as machine learning-assisted nanozyme design, are also discussed. Overall, this review highlights the potential of nanozymes as antibiofilm agents and provides insights into the future design of nanozymes for biofilm control.

Traditional Fenton oxidation is an effective method for reducing pollutants that are difficult to degrade. Owing to the large amounts of Fe(II), acids, and alkalis added in the reaction, large amounts of Fenton sludge are produced, increasing treatment costs and restricting the method’s application. In this study, we developed a three-dimensional electro-Fenton system by adding iron-carbon filler and investigated the effects of different electrolytic cell structure arrangements, particle electrode dosages, sponge iron (SI) to granular activated carbon (GAC) dosage ratios, current densities, H₂O₂ dosages, and cathodic aeration on nitrobenzene (NB) wastewater treatment. The optimal system conditions were a particle electrode dosage of 100 g/L, SI:GAC mass ratio of 3:1, current density of 30 mA/cm², H₂O₂ dosage of 50 mmol/L, cathodic aeration of 0.8 L/min, and hydraulic retention time of 120 min. The average NB removal rate and chemical oxygen demand reached 67.38%±1.05% and 70.60%±1.15%, respectively, for which the increase in Fenton sludge was 891.8 mg/L. Different from the traditional Fenton process, additional Fe(II) was not required in the process used herein, reducing iron sludge accumulation and lowering the operating costs of using Fenton sludge as a hazardous waste treatment. In addition, the process applied in this study was able to reduce the chemical amounts used and increase the treatment efficiency. The reductions in sludge treatment costs and secondary pollutants make the proposed process an efficient and sustainable alternative for treating NB wastewater.

Changes in ozone (O₃) can be evaluated to inform policy effectiveness and develop reasonable emissions reduction measures. This study investigated the causes of summertime maximum daily 8-h average (MDA8) O₃ variation between 2015 and 2020 in Nanjing, China, a megacity in the Yangtze River Delta (YRD) region, from the perspective of meteorological conditions and anthropogenic emissions of O₃ precursors (VOCs and No_x). Compared with 2015, the observed MDA8 O₃ decreased by 19.1 µg/m³ in August 2020. The indirect and indirect impacts of meteorological conditions contributed 44% of the decline, with temperature, relative humidity, and wind playing important roles in the O₃ variation. The O₃ drop by 10.7 µg/m³ (56% of the total decrease) may have been due to the decreases in anthropogenic emissions of VOCs and NO_x by 7.8% and 11.7%, respectively. The longer hydroxyl (OH) radical chain length and higher ozone production efficiency (OPE) indicated that the reduction of anthropogenic emissions accelerated the RO_x (RO_x = OH + HO₂ + RO₂) and NO_x cycles in O₃ production, making O₃ more sensitive to NO_x. This corresponded to the O₃ formation shifting from a VOC-limited regime in 2015 to a transition regime in 2020 and O₃ decrease with anthropogenic emission reduction. Hence, the joint control of O₃ precursor emissions can effectively mitigate O₃ pollution in Nanjing.

Emerging contaminants (ECs) have drawn global concern, and the endocrine disrupting chemicals is one of the highly interested ECs categories. However, numerous ECs lacks the basic information about whether they can disturb the endocrine related biomacromolecules or elicit endocrine related detrimental effects on organism. In this study, the potential binding affinity and underlying binding mechanism between 29 ECs from 7 chemical groups and Gobiocypris rarus transthyretin (CrmTTR) are investigated and probed using in vitro and in silico methods. The experimental results demonstrate that 14 selected ECs (11 disinfection byproducts, 1 pharmaceuticals and personal care product, 1 alkylphenol, 1 perfluoroalkyl and polyfluoroalkyl substance) are potential CrmTTR binders. The CrmTTR binding affinity of three ECs (i.e., 2,6-diiodo-4-nitrophenol (logRP(T₄) = 0.678 ± 0.198), 2-bromo-6-chloro-4-nitrophenol (logRP(T₄) = 0.399 ± 0.0908), tetrachloro-1,4-benzoquinone (logRP(T₄) = 0.272 ± 0.0655)) were higher than that of 3,3′,5,5′-tetraiodo-L-thyronine, highlighting that more work should be performed to reveal their potential endocrine related harmful effects on Gobiocypris rarus. Molecular docking results imply that hydrogen bond and hydrophobic interactions are the dominated non-covalent interactions between the active disruptors and CrmTTR. The optimum mechanism-based (for CrmTTR), and high throughput screening (for CrmTTR, little skate-TTR, seabream-TTR, and human-TTR) binary classification models are developed using three machine learning algorithms, and all the models have good classification performance. To facilitate the use of developed high throughput screening models, a tool named “TTR Profiler” is derived, which could be employed to determine whether a given substance is a potential CrmTTR, little skate-TTR, seabream-TTR, or human-TTR disruptor or not.

Mining activities typically discharge considerable amounts of heavy metals into the environment, raising concerns about soil metal pollution, environmental security, and human well-being. Therefore, a systematic regional-scale investigation of soil heavy metal pollution in mining areas is necessary for soil management. In this study, 5817 soil samples from the Huainan coal mining area collected for studies conducted from 2000 to 2021 were compiled to quantify the pollution level and spatiotemporal variation of heavy metals (Cu, Pb, Zn, Cr, Cd, As, Hg, Ni, and Mn). The associated ecological health risk of heavy metals in soil was assessed using the Hakanson ecological hazard index, Monte Carlo simulation in conjunction with the total hazard quotient, and the hazard index. Cd was the top contaminant, followed by Hg. In terms of spatial distribution, heavy metal contamination was more severe in the eastern area of Fengtai and Datong districts, because these districts of Anhui Province are significant industrial regions. In addition, the results of the Monte Carlo evaluation of human health risks showed that the total noncarcinogenic risk of heavy metals in soil is below the acceptable level, while the carcinogenic risk was 5.97% for adults and 15.53% for children. As accounted for 57.4% of noncarcinogenic risk, Cr contributed 36.1% of carcinogenic risk. Compared with adults, children are more vulnerable to the carcinogenic and noncarcinogenic risks posed by heavy metals, with oral consumption being the primary exposure route. This research can provide useful details for protecting the environment and managing soil in a coal mining area.

Amidst increasing concerns about plastic pollution’s impacts on ecology and health, nanoplastics are gaining global recognition as emerging environmental hazards. This review aimed to examine the complex molecular consequences and underlying fundamental toxicity mechanisms reported from the exposure of diverse aquatic organisms to nanoplastics. Through the comprehensive examination of transcriptomics, proteomics, and metabolomics studies, we explored the intricate toxicodynamics of nanoplastics in aquatic species. The review raised essential questions about the consistency of findings across different omics approaches, the value of combining these omics tools to understand better and predict ecotoxicity, and the potential differences in molecular responses between species. By amalgamating insights from 37 omics studies (transcriptome 22, proteome six, and metabolome nine) published from 2013 to 2023, the review uncovered both shared and distinct toxic effects and mechanisms in which nanoplastics can affect aquatic life, and recommendations were provided for advancing omics-based research on nanoplastic pollution. This comprehensive review illuminates the nuanced connections between nanoplastic exposure and aquatic ecosystems, offering crucial insights into the complex mechanisms that may drive toxicity in aquatic environments.

The large amount of refractory organic wastewater produced from industry and agriculture sectors poses a significant threat to both water ecosystems and human health, necessitating the exploration of cost-efficient and efficacious removal techniques. Persulfate, when activated by various catalysts, can produce oxidative species, demonstrating promising potential in remediating organic wastewater. In recent years, numerous studies have unveiled that persulfate can be readily decomposed into nonradicals, which exhibits high selectivity toward pollutants and robust performance in complex wastewater environments. However, the challenges in identifying non-radicals and the unclear catalytic mechanism hinder its further application. This paper critically reviews the research progress on non-radical oxidation in persulfate-based heterogeneous catalytic system. The main advancements and existing challenges in three non-radical oxidation pathways, i.e., singlet oxygen, electron transfer, and high-valent metal oxides, are summarized, and the key factors influencing the production of nonradicals are elaborated. The engineering aspects of non-radical oxidation system are further discussed, and the future prospects of this technology in wastewater treatment are envisaged. This review aims to bridge the knowledge gaps between current research and future requirements.