Cover illustration
Front Cover Story (See: Guochao Chen, Minghao Qiu, Peng Wang, Yuqiang Zhang, Drew Shindell, Hongliang Zhang, 2024, 18(10): 130)
Wildfires burn approximately 3%–4% of the global land area annually, resulting in massive emissions of greenhouse gases and air pollutants. During the past two decades, a consistent declining trend has been observed in both burned area and wildfire emissions on a global scale. However, the northern high-latitude regions of Asia and North Ameri
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● “Forever chemicals” are being redefined in terms of environmental lifespans.
● Novel degradation technologies offer promising PFAS remediation solutions.
● Global Collaboration in responding to the PFAS crisis is emphasized.
The discovery and widespread use of per- and poly-fluoroalkyl substances (PFAS) have exemplified the beneficial role of chemistry in modern life, yet they have also underscored significant environmental and health concerns. Termed “forever chemicals” due to their remarkable persistence, PFAS present formidable challenges in terms of contamination and toxicity. Efforts to address these challenges have led to the development of innovative degradation technologies, such as hydrothermal alkali treatment (HALT), low-temperature mineralization, and mechanochemical degradation, offering promising solutions to PFAS remediation. However, these advancements must be accompanied by robust investment in research, collaboration among stakeholders, and global responsibility to ensure effective management of PFAS contamination and mitigate its adverse impacts on ecosystems and human health.
● Wildfire and emission patterns vary globally, intensifying at high latitudes.
● Climate change-driven warming and drought are key in wildfire patterns.
● Wildfires impact health, especially in high-emission areas, lack management.
Wildfires burn approximately 3%–4% of the global land area annually, resulting in massive emissions of greenhouse gases and air pollutants. Over the past two decades, there has been a declining trend in both global burned area and wildfire emissions. This trend is largely attributed to a decrease in wildfire activity in Africa, which accounts for a substantial portion of the total burned area and emissions. However, the northern high-latitude regions of Asia and North America have witnessed substantial interannual variability in wildfire activity, with several severe events occurring in recent years. Climate plays a pivotal role in influencing wildfire activity and has led to more wildfires in high-latitude regions. These wildfires pose significant threats to climate, ecosystems, and human health. Given recent changes in wildfire patterns and their impacts, it is critical to understand the contributors of wildfires, focus on deteriorating high-latitude areas, and address health risks in poorly managed areas to mitigate wildfire effects.
● We built a read-mapping framework to profile human microbes from sewages (HSM).
● There were 95.03% human microbial species successfully recaptured from sewages.
● The HSM composition showed a distance-decay pattern at a global scale.
● The HSM communities from developed regions were separated from developing regions.
● Economy was the key socioeconomic factors driving the HSM diversity.
The human microbiome leaves a legacy in sewage ecosystems, also referred to as the human sewage microbiomes (HSM), and could cause potential risk to human health and ecosystem service. However, these host-associated communities remain understudied, especially at a global scale, regarding microbial diversity, community composition and the underlying drivers. Here, we built a metagenomic read mapping-based framework to estimate HSM abundance in 243 sewage samples from 60 countries across seven continents. Our approach revealed that 95.03% of human microbiome species were identified from global sewage, demonstrating the potential of sewage as a lens to explore these human-associated microbes while bypassing the limitations of human privacy concerns. We identified significant biogeographic patterns for the HSM community, with species richness increasing toward high latitudes and composition showing a distance-decay relationship at a global scale. Interestingly, the HSM communities were mainly clustered by continent, with those from Europe and North America being separated from Asia and Africa. Furthermore, global HSM diversity was shown to be shaped by both climate and socioeconomic variables. Specifically, the average annual temperature was identified as the most important factor for species richness (33.18%), whereas economic variables such as country export in goods and services contributed the most to the variation in community composition (27.53%). Economic and other socioeconomic variables, such as education, were demonstrated to have direct effects on the HSM, as indicated by structural equation modeling. Our study provides the global biogeography of human sewage microbiomes and highlights the economy as an important socioeconomic factor driving host-associated community composition.
● Identifies and elucidates the concurrent thermal degradation and hydrolysis of common binders in flexible plastic packaging during mechanical recycling.
● Reveals that thermal degradation for a variety of binder resins begins between 200–300 °C, with hydrolysis potentially intensified by humidity from cleaning processes.
● Demonstrates how the compatibility between binder resins and polyolefin affects the quality of recycled plastics, emphasizing this issue regarding immiscibility.
● Underscores the influence of binder resins and their degradation products on the efficacy of advanced recycling methods like selective dissolution-precipitation and pyrolysis.
This review covers the decomposition mechanisms of various printing ink binder resins, with a particular focus on their behavior under extrusion conditions in the mechanical recycling process of polyolefin (PO) based plastic packaging. Thermal degradation and hydrolysis of the nitrocellulose (NC) ─ the most used binder for flexographic surface printing on single-layer flexible plastic packaging, occur concurrently during the mechanical recycling process under 160–210 °C. For other printing ink binders, polyurethane (PU) noticeable degradation takes place between 200 and 300 °C, mostly above 250 °C. However, with the involvement of humidity, degradation by hydrolysis can start from 150 °C. A similar effect is also discovered with the cellulose acetate (CA) derivatives, which are thermally stable until 300 °C and can be hydrolyzed at 100 °C. The thermal stability of polyvinyl butyral (PVB) is not influenced by humidity, with thermal stability ranging from 170 to 260 °C, depending on different types. Ultraviolet (UV)-cured acrylics are thermally stable until 400 °C. The hydrolysis degradation can take place at room temperature. Moreover, this review covers the thermal stability of different colorants used for printing ink application and elaborates on several thermal-stable alternatives of some common colors. This study further reviews how the binder resin affects the quality of recyclates, revealing it to be not only induced by the degradation of the binder resin but also by the immiscibility between the plastic and binder resin. In advanced recycling processes, mainly selective dissolution-precipitation and pyrolysis, the presence of binder resin and its degradation products could still affect the quality of the product. This review accentuates the imperative need for in-depth research to unravel the impact of printing ink constituents on the quality of recycled products.
● Amitriptyline in drinking water can be effectively removed by UV/Chlorine treatment.
● UV/Chlorine can enhance the biodegradability of Amitriptyline.
● UV/Chlorine-BAC can remove Amitriptyline and purify water quality.
● The optimal parameters for UV/Chlorine-BAC operation were determined.
● Microbial communities evolve towards promoting long-term operational benefits.
The environmental pollution caused by psychotropic drugs harms human health and has prompted a stronger emphasis on research into water treatment measures. The UV/Chlorine-biological activated carbon (BAC) combined process was employed in this study to treat amitriptyline (AMT), a typical psychotropic drug, in slightly contaminated drinking water. The removal efficiency of AMT in drinking water by UV/Chlorine and the feasibility of combining it with BAC were determined. The results demonstrated that the removal efficiency of 1 μmol/L AMT could reach 98.5% of the 2.0 mg/L chlorine and UV treated for 30 min. A significant removal improvement of AMT was 10%–45% compared to UV alone, Chlorine alone, and other oxidants combined, especially the SOUR (Specific Oxygen Uptake Rate), which was 57%–90% compared to other oxidants combined. Secondly, the optimal process parameters for UV/Chlorine-BAC treatment of slightly contaminated drinking water were a combination of UV exposure, chlorine dosage of 2 mg/L, and reaction times of 15 min followed by 30 min of BAC treatment. The AMT degradation, CODMn removal efficiency, and NO3−–N production was 88%, 65%, and 95%, respectively. There was no significant effect on the number of microorganisms in the BAC medium, ensuring good long-term operation. Furthermore, an investigation was conducted to assess the influence of optimal process operation on the microbial community structure within BAC. This analysis unveiled a positive feedback loop in the colony architecture after implementing ideal process parameters. This study provides significant inspiration for addressing residual antidepressant issues using traditional drinking water treatment processes.
● Class 1 integrons are prevalent in the isolates from drinking water.
● High proportion of intI 1-positive bacteria are resistant to aminoglycosides.
● Chlorination can significantly affect the abundance of intI 1 in drinking water.
● The composition of ARGs and GCAs are shifted after drinking water chlorination.
Class 1 integrons are vital mobile genetic elements involved in the environmental transmission of antibiotic resistance genes (ARGs). However, knowledge about the diversity and abundance of class 1 integrons and gene cassettes during drinking water treatment and distribution is still limited. In this study, we aimed to uncover the prevalence of class 1 integrons in the drinking water treatment and distribution systems with the combination of culture-dependent and culture-independent methods. Further, we applied the nanopore sequencing method to characterize the diversity and arrangement of ARGs carried by class 1 integron-associated gene cassettes. A total of 42 isolates were intI1-positive among the 208 strains isolated from drinking water, which tended to confer multi-drug resistance compared with intI1-negative isolates. The absolute abundance of the intI1 average 1.15 × 109 copies/L in the source water and underwent the most significant reduction of over 99.9% after liquid chlorine disinfection. Furthermore, nanopore sequencing revealed that the class 1 integron-associated gene cassettes carried 51 subtypes of ARGs in drinking water, mainly conferring resistance to aminoglycosides and trimethoprim. The treatment processes, especially liquid chlorine disinfection, reduced most of the ARGs carried by gene cassettes, though some of the ARG subtypes persisted along the treatment and distribution like aac(6')-II, aadA, and dfrB2. The antibiotic resistance gene cassette array |aac(6')-II|arr| was most frequently detected, especially in the chlorinated water. This study underlined that drinking water was potential reservoir for integron-mediated ARGs transfer, indicating that the health risks of resistance gene cassettes in class 1 integrons deserved urgent attention.
● Municipal solid waste storage sites show high microplastic adsorption
● Ventilation promotes the secondary release of microplastics
● Flushing reduces microplastic accumulation by 76.4% in walls
● Microplastic sizes predominantly between 1 and 50 µm
● Seasonal extremum in microplastics dispersion identified in summer and winter
Municipal solid waste (MSW) storage sites are potential and overlooked contributors to microplastic (MP) pollution. Herein, the distribution and dispersion characteristics of MPs at MSW storage sites were investigated through modeling, sampling analysis, and prediction methodologies. The results indicated a notable adsorption phenomenon of MPs on smooth surfaces within such sites, achieving high saturation levels and making MPs prone to re-release by airflow disturbance. Quantitative analysis revealed that the MP concentrations on these surfaces varied from 4.48 × 105 to 1.90 × 106 n/m2 and that MPs predominantly accumulated in the corner areas. Notably, MP accumulation on wall surfaces can be reduced by 76.4% using washing procedures. The majority of MPs were under 50 μm in size and were primarily in fragment form. Operational activities such as ventilation and waste handling were identified to amplify the airborne spread of MPs. The atmospheric concentrations of MPs peaked seasonally, with concentrations of 28.25 n/m3 in summer and 3.90 n/m3 in winter, and the spatial dispersion ranged from 14.98 to 124.08 km2 per station. This study highlights that MSW storage sites are substantial yet overlooked sources of MP pollution, where wall surfaces play a critical role in MP adsorption and dispersal. The implementation of robust management and cleaning protocols is essential to mitigate the environmental footprint of MPs emanating from these locations. This study also provides a typical case for the precise prevention and control of MPs in the environment.
● Catalytic ozonation could effectively purify the secondary effluent from IPWWTPs.
● High removal on COD, UV254 and TOC were obtained in the Mn-based catalyst/O3 system.
● Mn-based catalytic ozonation preferred to degrade aromatic contaminants in wastewater.
● ·O2‒/HO2· and 1O2 dominated contaminants removal in the Mn-based catalyst/O3 system.
Catalytic ozonation is a potential technology to eliminate refractory organic contaminants with the low concentration in secondary effluent from industrial park wastewater treatment plants (IPWWTPs). In this study, the catalytic ozonation over the Mn-based catalyst significantly improved the chemical oxygen demand (COD), total organic carbon (TOC), and UV254 removals of secondary effluent from IPWWTPs. The Mn-based catalyst/O3 system achieved 84.8%, 69.8%, and 86.4% removals of COD, TOC, and UV254, which were 3.3, 5.7, and 1.1 times that in ozonation alone, respectively. Moreover, the Mn-based catalytic ozonation process exhibited excellent pH tolerance ranging from pH 4.0 to 9.0. Additionally, the depth analysis based on fluorescence excitation-emission matrix (EEM) confirmed that the catalytic ozonation process preferred to degrade toxic aromatic hydrocarbons. The existence of the Mn-based catalyst/O3 system enhanced 21.4%–38.3% more fluorescent organic matters removal, compared to that in ozonation alone. Mechanistic studies proved that the abundant Lewis acid sites (Mnn+/Mn(n+1)+ and adsorbed oxygen) on the surface of the Mn-based catalyst effectively promoted O3 decomposition into reactive oxygen species (ROS), and ·O2‒/HO2· and 1O2 were the main ROS for degrading refractory organic contaminants. The contributions of ROS oxidation (91.2%) was much higher than that of direct O3 oxidation (8.8%). Thus, this work provides an effective advanced treatment process for purifying secondary effluent from IPWWTPs.
● TiO2 nanoparticles are generated in situ on layered Ti3C2 MXene.
● TiO2/Ti3C2 photocatalytic ceramic membrane enables one-step solid-liquid separation.
● The membrane enhances photocatalytic degradation of PPCPs like CIP, TCN, and IBP.
● Calcination increased membrane flux from 80 to 320 L/(m2·h).
● The ceramic membranes exhibit good stability and have broad market prospects.
Photocatalytic membranes offer an effective strategy to overcome the difficulties of solid-liquid separation and secondary contamination of powdered photocatalysts. MXene is a 2D material of layered Ti3C2, which is considered to limit electron-hole separation and contribute to photocatalysis. In this work, the etched Ti3C2 MXene was loaded on the surface of ceramic membranes using polydopamine (PDA) as a binder, followed by one-step calcination to produce TiO2 nanoparticles (NPs) in situ. The characterizations supported that the TiO2/Ti3C2 ceramic membranes had high mechanical strength while retaining the layered structure of Ti3C2, which was conducive to the inhibition of electron and hole complexation, improving the photocatalytic performance. Degradation experiments revealed that the material showed enhanced degradation of pharmaceuticals and personal care products (PPCPs) such as ciprofloxacin (CIP), tetracycline (TCN) and ibuprofen (IBP). The LC-MS and toxicity prediction models indicated that the developmental toxicity of CIP degradation products decreased with prolonged photocatalytic reaction, exhibiting no acute toxicity to fish. The MT650 exhibited significantly enhanced water flux properties (320 L/(m2·h)). The TiO2/Ti3C2 ceramic membranes explored in this work are expected to target the treatment of PPCPs with excellent engineering promise.
● The spatiotemporal distribution of soil heavy metals from mining area was analyzed.
● The potential ecological risk of heavy metals in soil of Huainan mining area was analyzed.
● Monte Carlo method was used to analyze the health risks of heavy metals to humans.
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.
● Ambient NO2 may be associated with self-rated health (SRH) in floating populations.
● NO2 exposure was associated with an increased risk of poor SRH.
● Each grade increment of annual average NO2 increased the risk of poor SRH 2.4%.
● Floating individuals aged 31–49 years were at highest risk of NO2 associated SRH.
● Risk of NO2 associated SRH was higher in regions with mid-level per capita GDP.
Few studies investigated the effects of exposure to NO2 on health status in the Chinese floating population. The present cross-sectional study evaluated the association of ambient NO2 with health status in a floating population in China. Data on 168961 floating individuals in 338 cities were obtained from the 2017 China Migrants Dynamic Survey. The association between exposure to NO2 and self-related health (SRH) status was assessed by binary logistic regression analysis, both in the entire subject cohort and in subgroups assorted by socioeconomic levels and demographic characteristics. The robustness of the associations between NO2 exposure and health status was evaluated by sensitivity analyses. Each grade increment of annual average NO2 exposure was found to increase the risk of poor SRH by 2.4% in the floating population (odds ratio [OR] = 1.024, 95% confidence interval [CI]: 1.011–1.038). When subgrouped by age, subjects in the floating population aged 31–49 years had the highest NO2 associated health risk (OR = 1.036, 95% CI: 1.018–1.054). When subgrouped by per capita gross domestic product (PGDP), subjects in regions with mid-level PDGP had the highest NO2 associated SRH (OR = 1.116, 95% CI: 1.091–1.141). These findings indicated that exposure to NO2 increases the risk of poor SRH in the floating population, with individuals aged 31–49 years and those living in mid-level PGDP regions being more sensitive to the adverse effects of NO2. More effective strategies to reduce air pollution may improve the health status of the floating population in China.
● Microbiologically influenced corrosion is reviewed focusing on its mechanisms and mitigation
● MIC mechanisms help understand the complex interaction of microbes and metallic surfaces
● Traditional and advanced monitoring techniques for diagnosing and assessing MIC are discussed
● Application of various biocides are highlighted, along with their performance enhancement strategies
● Enzymatic remediation is explored as a sustainable alternative approach for MIC mitigation
Microbiologically induced corrosion (MIC) is a complex and destructive phenomenon that occurs in various sectors, involving the interaction between microorganisms and metal surfaces, resulting in accelerated corrosion rates. This review article provides a comprehensive analysis of MIC, encompassing microbial species involved, their metabolic activities, and influential environmental factors driving the corrosion process. The mechanisms of MIC, both in the presence and absence of oxygen, are explored, along with the diverse effects of microbes on different types of corrosion and their economic impacts. Assessment and monitoring techniques, including traditional and advanced methods such as microbiological and electrochemical methods, are discussed. Furthermore, it examines preventive and control measures, such as the use of biocides and their mechanisms of action. Strategies to enhance the performance of these control measures and the effectiveness of antimicrobial agents during disinfection processes, including surfactants and chelators, are discussed. Additionally, the review highlights enzymatic remediation as a sustainable alternative approach, providing detailed examples. The challenges in mitigating MIC and potential future developments and collaborative opportunities are also addressed. This systematic review is a valuable resource for researchers, industry professionals, and policymakers seeking a comprehensive understanding of the complex phenomenon of MIC and effective strategies for its management.
● Sewer network contributes to greenhouse gas emissions.
● Branch pipes contribute a higher portion to greenhouse gas emissions.
● CH4 is the major greenhouse gas in sewer networks.
● Most CH4 is produced via acetate fermentation.
Sewer networks play a vital role in sewage collection and transportation, and they are being rapidly expanded. However, the microbial processes occurring within these networks have emerged as significant contributors to greenhouse gas (GHG) emissions. Compared to that from other sectors, our understanding of the magnitude of GHG emissions from sewer networks is currently limited. In this study, we conducted a GHG emission assessment in an independent sewer network located in Beijing, China. The findings revealed annual emissions of 62.3 kg CH4 and 0.753 kg N2O. CH4 emerged as the primary GHG emitted from sewers, accounting for 87.4% of the total GHG emissions. Interestingly, compared with main pipes, branch pipes were responsible for a larger share of GHG emissions, contributing to 76.7% of the total. A GHG emission factor of 0.26 kg CO2-eq/(m·yr) was established to quantify sewer GHG emissions. By examining the isotopic signatures of CO2/CH4 pairs, it was determined that CH4 production in sewers primarily occurred through acetate fermentation. Additionally, the structure of sewer pipes had a significant impact on GHG levels. This study offers valuable insights into the overall GHG emissions associated with sewer networks and sheds light on the mechanisms driving these emissions.
