The decomposition of polyethylene (PE), an extremely recalcitrant synthetic polymer, using microorganisms is an ideal and sustainable method for future PE biotreatment. We isolated a set of PE-biodegrading Bacillus species from a landfill site. Among them, Bacillus thuringiensis JNU01 exhibited the highest cell growth rate in PE media, which means it effectively decomposed PE to use in the metabolic pathway as a sole carbon source. B. thuringiensis JNU01-treated PE showed new chemical functional groups such as hydroxyl, carboxyl, and amide groups in the inert hydrocarbon. Scanning electron microscopy revealed considerable physical damage on the surface of the PE film after treatment with B. thuringiensis JNU01. Furthermore, various alkane derivatives obtained from PE were characterized using gas chromatography–mass spectrometry. On the contrary, an increase in the mRNA transcriptional levels of B. thuringiensis JNU01 in the presence of PE suggests that a CYP102A5 variant (CYP102A5.v1) is involved in PE biodegradation. Finally, we confirmed that purified CYP102A5.v1 catalyzes the hydroxylation of PE by a NADPH oxidation assay and Fourier transform infrared analysis. These results show that B. thuringiensis JNU01 is a potential PE decomposer and suggest that CYP102A5.v1 can be a trigger biocatalyst for hydroxylation of PE.

Recent evidence suggests that products of indoor ozone chemistry contribute to cardiovascular pathophysiology. A hypothetical exposure pathway is the formation of reactive oxygen species (ROS) on indoor surfaces, and subsequent partitioning of ROS to respirable particulate matter (PM). For this pathway to be relevant, the ozone-initiated surface yield of ROS should be large enough to contribute substantially to total ROS intake by PM. Here, we exposed a model indoor surface film comprising a mixture of skin and cooking oil lipids to ozone and measured the yield of condensed-phase ROS using a colorimetric method sensitive primarily to hydroperoxides and calibrated with hydrogen peroxide. Approximately 46% of the ozone that was consumed in the reaction formed ROS on a molar basis. Approximately half of the ROS formed is persistent for at least several hours on the surface. ROS continued to form in the absence of ozone, suggesting that a mechanism other than ozonation continues to oxidize the lipids, such as autoxidation. The yields observed here are well above that necessary to contribute to the ROS airborne concentrations observed in field studies.

Krypton chloride (KrCl*) excilamps emitting at far-UVC 222 nm represent a promising technology for microbial disinfection and advanced oxidation of organic micropollutants (OMPs) in water treatment. However, direct photolysis rates and photochemical properties at 222 nm are largely unknown for common OMPs. In this study, we evaluated photolysis for 46 OMPs by a KrCl* excilamp and compared it with a low-pressure mercury UV lamp. Generally, OMP photolysis was greatly enhanced at 222 nm with fluence rate-normalized rate constants of 0.2–21.6 cm2·μEinstein–1, regardless of whether they feature higher or lower absorbance at 222 nm than at 254 nm. The photolysis rate constants and quantum yields were 10–100 and 1.1–47 times higher, respectively, than those at 254 nm for most OMPs. The enhanced photolysis at 222 nm was mainly caused by strong light absorbance for non-nitrogenous, aniline-like, and triazine OMPs, while notably higher quantum yield (4–47 times of that at 254 nm) occurred for nitrogenous OMPs. At 222 nm, humic acid can inhibit OMP photolysis by light screening and potentially by quenching intermediates, while nitrate/nitrite may contribute more than others to screen light. Overall, KrCl* excilamps are promising in achieving effective OMP photolysis and merit further research.

Nonsenescent and senescent leaves of selected coniferous and broadleaf plants contained substantial levels of naturally occurring persistent free radicals (PFRs). These biogenic PFRs (BPFRs) were stable and persistent despite multiple wetting and drying cycles, implying that BPFRs can leach and sorb on soil particles. Results suggest that endogenous chemicals in plants and their transformation byproducts can stabilize unpaired electrons in leaves under ambient conditions. Thus, the vast amount and perpetual supply of leaf litter is an unaccounted natural source of BPFRs. If toxic, inhaling and accidentally ingesting fine soil dust and powder from degraded leaf litter may increase our environmental and health burdens to PFRs. We expect that this finding will generate more studies on natural sources of PFRs, establish their properties, and distinguish them from those formed from combustion and thermal processes.

Industrial and agricultural chemicals: hazardous properties, ongoing worldwide uses, releases and presence, control measures, alternative technologies (chemical and nonchemical), and associated environmental, social, and economic dynamics and impacts. Wastes: sound management of different types of wastes. Biodiversity: monitoring for the new global biodiversity framework. Governance and legal matters: review and improvement of financial mechanisms, capacity building, and technical assistance in the Global South, and design of new international instruments. Figure 1. Timeline of major international negotiations on chemicals and waste management in 2023. Regularly checking the meeting websites for updates of meeting documents, particularly the agendas and the scenario note. These documents provide insights into the likely meeting flow, particularly which key topics will be approached and how, as well as providing references to relevant background documents and other submissions. Attending preparatory events such as regional meetings, webinars, and briefings. They typically provide an outcome summary of the previous meeting and/or updates on the preparations for the current meeting. One may regularly check the websites of the Committee of Permanent Representatives to the United Nations Environment Programme (http://www.unep.org/cpr/meetings) and the Geneva Environment Network (http://www.genevaenvironmentnetwork.org/events/) for such events. Checking the official decisions, reports, and summaries of previous meeting(s) for the specific mandates on the topics. (3) Other unofficial reports such as those prepared by the Earth Negotiations Bulletin (http://enb.iisd.org/topics/chemicals-wastes) are also good sources of information. Identifying and consulting with experts that are familiar with the processes for insights on the policy needs, including active national/sectoral focal points, civil society organizations, and individuals. They can be identified through preparatory events and reports of previous meeting(s) as indicated above, as well as through the lists of focal points and participants on the meeting websites. (1) The Supporting Information is available free of charge at http://pubs.acs.org/doi/10.1021/acs.estlett.3c00219. Table S1: Overview of major international negotiations on chemicals and waste in 2023 (PDF) Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html. Dr. Zhanyun Wang has recently joined the Technology & Society Laboratory at the Swiss Federal Laboratories for Materials Science and Technology (EMPA). He is an environmental chemist by training, and his research interests focus primarily on understanding the life cycles and risks of various anthropogenic chemicals in the technosphere and natural environment. He is also very interested in exploring novel and pragmatic approaches to advancing sound chemicals management, enabling a sustainable circular economy, and strengthening the science–policy interface on chemicals and waste. The authors gratefully acknowledge Dr. David Santillo (Greenpeace Research Laboratories) for helpful comments. Z.W. gratefully acknowledges funding by the European Union under the Horizon 2020 Research and Innovation Programme (Project ZeroPM, grant agreement number 101036756) and from the Geneva Science–Policy Interface (GSPI) via its Impact Collaboration Programme (www.gspi.ch). The views and opinions expressed in this publication are those of the authors and independent of the views or official policies of their organizations. This article references 3 other publications. This article has not yet been cited by other publications. Figure 1. Timeline of major international negotiations on chemicals and waste management in 2023. Dr. Zhanyun Wang has recently joined the Technology & Society Laboratory at the Swiss Federal Laboratories for Materials Science and Technology (EMPA). He is an environmental chemist by training, and his research interests focus primarily on understanding the life cycles and risks of various anthropogenic chemicals in the technosphere and natural environment. He is also very interested in exploring novel and pragmatic approaches to advancing sound chemicals management, enabling a sustainable circular economy, and strengthening the science–policy interface on chemicals and waste. This article references 3 other publications. The Supporting Information is available free of charge at http://pubs.acs.org/doi/10.1021/acs.estlett.3c00219. Table S1: Overview of major international negotiations on chemicals and waste in 2023 (PDF) Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system: http://pubs.acs.org/page/copyright/permissions.html.

Compostable plastics support the separate collection of organic waste. However, there are concerns that the fragments generated during disintegration might not fully biodegrade and leave persistent microplastic in compost. We spiked particles of an aromatic–aliphatic polyester containing polylactide into compost and then tracked disintegration under industrial composting conditions. We compared the yields against polyethylene. The validity of the extraction protocol and complementary microscopic methods (μ-Raman and fluorescence) was assessed by blank controls, spike controls, and prelabeled plastics. Fragments of 25–75 μm size represented the most pronounced peak of interim fragmentation, which was reached already after 1 week of industrial composting. Larger sizes peaked earlier, while smaller sizes peaked later and remained less frequent. For particles of all sizes, count and mass decreased to blank level when 90% of the polymer carbon were transformed into CO2. Gel permeation chromatography (GPC) analysis suggested depolymerization as the main driving force for disintegration. A transient shift of the particle composition to a lower percentage of polylactide was observed. Plastic fragmentation during biodegradation is the expected route for decomposing, but no accumulation of particulate fragments of any size was observed.

Pressure-driven distillation is a separation process in which hydraulic pressure is used to drive water vapor transport across an air-trapping porous hydrophobic membrane. Current development of pressure-driven distillation is limited by a lack of robust, large-area membranes. Here, we report desalination using pressure-driven vapor transport through scalable polymeric polytetrafluorethylene membranes. The membranes showed pressure-driven water flow with near-complete rejection of sodium chloride (greater than 99%) under hydraulic pressures of up to 10.3 bar. Membrane structure, surface chemistry, and desalination performance were found to be unaffected by doses of sodium hypochlorite up to 3000 ppm h. Flux decline due to biofouling from Pseudomonas aeruginosa bacterium was effectively mitigated using chlorine. Membranes also exhibited high temperature resilience with operation up to 60 °C. Overall, this work demonstrates the use of large-area polymeric materials in pressure-driven distillation and highlights key advantages in chlorine and heat tolerance.

On February 3, 2023, a train carrying numerous hazardous chemicals derailed in East Palestine, OH, spurring temporary evacuation of residents and a controlled burn of some of the hazardous cargo. Residents reported health symptoms, including headaches and respiratory, skin, and eye irritation. Initial data from U.S. Environmental Protection Agency (EPA) stationary air monitors indicated levels of potential concern for air toxics based on hazard quotient calculations. To provide complementary data, we conducted mobile air quality sampling on February 20 and 21 using proton transfer reaction-mass spectrometry. Measurements were taken at 1 s intervals along routes designed to sample both close to and farther from the derailment. Mobile air monitoring indicated that average concentrations of benzene, toluene, xylenes, and vinyl chloride were below minimal risk levels for intermediate and chronic exposures, similar to EPA stationary monitoring data. Levels of acrolein were high relative to those of other volatile organic compounds, with spatial analyses showing levels in East Palestine up to 6 times higher than the local rural background. Nontargeted analyses identified levels of additional unique compounds above background levels, some displaying spatiotemporal patterns similar to that of acrolein and others exhibiting distinct hot spots. These initial findings warrant follow-up mobile air quality monitoring to characterize longitudinal exposure and risk levels.

Since the development of antibiotics, microorganisms have developed resistance to the germicidal effects. (1,2) In 2019, 1.27 million people died due to antimicrobial resistance (AMR), which ranked higher than the mortality associated with human immunodeficiency virus (HIV) (864 000) and malaria (643 000). If left unchecked, approximately 10 million people could die annually from AMR by 2050. (3) To direct the effects of AMR comprehensively and put policies into place at the national level, in 2016 the United Nations called for coordinated action. (4) AMR Industry Alliance assists the pharmaceutical industries in putting into practice measures to reduce the potential influence of pharmaceutical manufacturing on the spread of AMR via one of its milestones to publish anticipated no-effect concentrations (PNECs) of known antibiotics. (5) Although several novel technologies and approaches have been developed for combating AMR, for example, reverse vaccinology, (6) structural vaccinology, (7) and artificially designed bacterial outer membrane vesicles (OMVs), (8) such developments and progress are moving too slowly to be effective. In this Highlight, we consider the impact of wars and pandemics on AMR and the potential for accelerated antimicrobial resistance development. With the rise of socioeconomic development, nuclear weapons, and technological development, war seems archaic. However, throughout the past several decades, the number of conflicts has increased, regardless of their ferocity, and a majority of them have continued to occur in developing countries. Eight times as many members of the British army perished from sickness during the Napoleonic wars than from wounds received in combat. Two-thirds of the projected military deaths during the American civil conflict were attributed to diseases such as dysentery, pneumonia, malaria, and typhoid, which was termed the third army, which prolonged the war by two years. (9) The disease-related death toll due to typhoid and cholera was 3.8 times greater than war deaths in the Crimean war. (10) Exposure to a war environment, unhygienic conditions [e.g., lice containing Bartonella quintana causing trench fever (11) and typhoid (Salmonella typhi)], war-related stress, and geopolitical consequences of war might impact immune systems leading to more susceptibility to diseases. The longer a war prevails, the more resources, including food, are diverted from the public, elevating health issues and weak immunity. In the Vietnam war (1955–1975), dextroamphetamine use increased from 3.2% to 5.2%. (12) War settings make it difficult or impossible to access medical help due to disrupted transportation networks and the destruction of healthcare facilities, leading to prolonged injuries without treatment that cause infections. Inoperative hospitals, migration to war-safe zones, and discontinuation of medications trigger secondary infection(s) and resistance to drug(s). In addition to the current COVID-19 pandemic, the globe has been struck by four major pandemics since 1900: Spanish Flu (1918), Asian Flu (1957), Hong Kong Flu (1968), and H1N1 Swine Flu (2009). Through wars and pandemics, new types of wounds, infections, and diseases emerge, urgently requiring medicines and treatment procedures, leading to a spike in the consumption and excretion of pharmaceutical products, in particular antibiotics. (13) The demand for pharmaceuticals in Portugal increased by 60% within a week after the World Health Organization declared COVID-19 a pandemic. India witnessed an increase of 38 million doses of azithromycin. In Wuhan, China, 71% of the nonsurvivors were treated with antibiotics. In addition, (i) sulfonamides introduced to treat Neisseria gonorrheae in the 1930s were found to be less effective in soldiers stationed in Italy and Sicily during WW II (1939–1945) and penicillin production increased approximately 325%, leading to subsequent reports of AMR (e.g., penicillin-resistant Escherichia coli in 1940). (ii) Tetracycline and erythromycin, which were extensively used during the Asian flu pandemic (1957–1958), became ineffective against Streptococcus pyogenes discovered in Japan in the mid-1970s. (iii) Ingavirin and oseltamivir, prescribed during the Russian Flu (1977–1979), were gradually found to be ineffective against influenza A virus when by 2007–08 oseltamivir resistance H1N1 was discovered. (iv) In the Syrian (since 2011) and Yemenis conflicts (since 2014), Klebsiella pneumoniae, E. coli, and Pseudomonas aeruginosa developed AMR to ciprofloxacin, gentamycin, tobramycin, and amikacin. (v) During the Iraq war (2003–2011), multidrug resistance Acinetobacter baumannii infection was spread. (vi) During the Ukrainian conflict (2014 to the present), bacteria like Acinetobacter, P. aeruginosa, E. coli, and Staphylococcus aureus acquired resistance to combat antibiotics such as fluoroquinolones, carbapenems, and relevant aminoglycosides. AMR is also fueled by heavy metal exposure from the demolition of the built environment and exudation of antibiotics from treatment plants during the war. This time line of war and discovery of drugs along with the developed resistance microbes, case fatality risk, mortality rate of human diseases, and time required for new drug discovery to clinical approval are summarized in Figure 1. Figure 1. (A) Timeline of war, conflicts, and disease outbreaks along with the occurrence of AMR. (B) Case fatality risk (CFR) (13) of various human diseases and mortality rates of common human pathogenic bacteria. (14) (C) Time line of the drug discovery process (15) (created with BioRender.com). The war in Ukraine is a reminder of the ongoing certainty of future conflict, and the COVID-19 pandemic is a reminder of the rapidity and force of a global disease. Antimicrobial resistance cannot be solved but is only effectively managed. The challenge for the international community is to address the issue of antibiotic resistance as quickly as possible as it occurs, whether through refining protocols of when antibiotics are prescribed, extensive R&D, etc. Novel research must focus on the rapid diagnosis of AMR. While the distribution of medicines and medical facilities should not be disrupted during the war, harmonized and standardized protocols should be formulated and disseminated globally in response to AMR development. Overtaxed hospitals must continue to prioritize hospital sanitation and staff hygiene to minimize the spread of resistant pathogens. In addition, international efforts are required to find alternative advanced treatments to combat new resistance infections. In summary, a rapid international strategy and response are necessary to effectively manage this silent and global AMR pandemic. M.K. conceptualized and visualized the work. R.S. and V.S. wrote the first draft of the manuscript with input from M.K. P.M. made the figure in consultation with M.K, reviewed the manuscript, and gave further input about the manuscript. M.K. then revised the manuscript with input from J.M., F.L., and D.B. Dr. Manish Kumar has been a Professor and Head of the Sustainability Cluster in the School of Engineering at UPES, Dehradun, India, since 2021. He serves as a Distinguished Professor in Water Science in the School of Engineering and Sciences, Tec de Monterrey, Mexico. After completing his Ph.D. from the University of Tokyo, Japan, he served on the faculty at Tezpur University, Assam, and Indian Institute of Technology (IIT) Gandhinagar, Gujarat, India. He worked at the University of Nebraska Lincoln (UNL), United States, as Visiting Faculty. His academic career has included work at Kunsan National University, South Korea; Uppsala University, Sweden; and JNU, New Delhi, India. He was featured in the list of the top 2% of the researchers in the world and is a Fellow of the Royal Society of Chemistry (FRSC). He was on the expert panel for UNEP on antimicrobial resistance. Dr. Kumar's research focuses on ascertaining, broadening, comprehending, and developing various dimensions of the fate, transport, and remediation of geogenic, micro, microbial, and emerging contaminants in freshwater systems. He renders editorial services to journals like Environmental Science & Technology Letters, ACS ES&T Engineering, npj Clean Water, Science of the Total Environment, Current Pollution Report, Groundwater for Sustainable Development, Reviews of Environmental Contamination and Toxicology, and Hydrological Research Letters. The authors are grateful for the support received from the Science and Engineering Research Board (SERB) of the Government of India, Department of Science and Technology, for supporting this ongoing research by a sponsored research project (SERB/CVD/2022/000033, May 2022). The authors also thank Tecnologico de Monterrey for bringing together some of the authors of this work and UPES, Dehradun, for hosting the project. This article references 15 other publications. This article has not yet been cited by other publications. Figure 1. (A) Timeline of war, conflicts, and disease outbreaks along with the occurrence of AMR. (B) Case fatality risk (CFR) (13) of various human diseases and mortality rates of common human pathogenic bacteria. (14) (C) Time line of the drug discovery process (15) (created with BioRender.com). Dr. Manish Kumar has been a Professor and Head of the Sustainability Cluster in the School of Engineering at UPES, Dehradun, India, since 2021. He serves as a Distinguished Professor in Water Science in the School of Engineering and Sciences, Tec de Monterrey, Mexico. After completing his Ph.D. from the University of Tokyo, Japan, he served on the faculty at Tezpur University, Assam, and Indian Institute of Technology (IIT) Gandhinagar, Gujarat, India. He worked at the University of Nebraska Lincoln (UNL), United States, as Visiting Faculty. His academic career has included work at Kunsan National University, South Korea; Uppsala University, Sweden; and JNU, New Delhi, India. He was featured in the list of the top 2% of the researchers in the world and is a Fellow of the Royal Society of Chemistry (FRSC). He was on the expert panel for UNEP on antimicrobial resistance. Dr. Kumar's research focuses on ascertaining, broadening, comprehending, and developing various dimensions of the fate, transport, and remediation of geogenic, micro, microbial, and emerging contaminants in freshwater systems. He renders editorial services to journals like Environmental Science & Technology Letters, ACS ES&T Engineering, npj Clean Water, Science of the Total Environment, Current Pollution Report, Groundwater for Sustainable Development, Reviews of Environmental Contamination and Toxicology, and Hydrological Research Letters. This article references 15 other publications.

Delhi, India, suffers from periods of very poor air quality, but little is known about the chemical production of secondary pollutants in this highly polluted environment. During the postmonsoon period in 2018, extremely high nighttime concentrations of NOx (NO and NO2) and volatile organic compounds (VOCs) were observed, with median NOx mixing ratios of ∼200 ppbV (maximum of ∼700 ppbV). A detailed chemical box model constrained to a comprehensive suite of speciated VOC and NOx measurements revealed very low nighttime concentrations of oxidants, NO3, O3, and OH, driven by high nighttime NO concentrations. This results in an atypical NO3 diel profile, not previously reported in other highly polluted urban environments, significantly perturbing nighttime radical oxidation chemistry. Low concentrations of oxidants and high nocturnal primary emissions coupled with a shallow boundary layer led to enhanced early morning photo-oxidation chemistry. This results in a temporal shift in peak O3 concentrations when compared to the premonsoon period (12:00 and 15:00 local time, respectively). This shift will likely have important implications on local air quality, and effective urban air quality management should consider the impacts of nighttime emission sources during the postmonsoon period.

The desire to quantify the presence of a wide range of polychlorinated biphenyls (PCBs) in air is driven both by an interest in the sources and fate of unintentionally produced congeners and in quantifying human inhalation exposure to volatile PCBs. The wide volatility range can introduce bias when sampling the entire suite of PCBs. Here, we present the result of a field calibration experiment that demonstrates that even the most volatile PCBs maintain linear uptake in a passive air sampler using XAD-resin as the sorbent (XAD-PAS). Empirically derived sampling rates (SRs) for 66 congeners decrease with the number of chlorines and, within a homologue, increase with the number of chlorines in the ortho-position. The large seasonal temperature range at the site of the calibration allowed for an estimation of the temperature dependence of the SRs. The effects of chlorine substitution and temperature can be expressed quantitatively through a regression relating the SR to the sorption constant to XAD from the gas phase. As a result, it is possible to estimate SRs for all congeners at any deployment temperature. The XAD-PAS is well suited for unbiased sampling of gaseous PCBs in a wide variety of settings.

The tire wear transformation product 6PPD-quinone (6PPDQ) has been implicated as the causative factor for broad scale mortality events for coho salmon in the Pacific Northwest. Highly variable sensitivity to 6PPDQ in closely related salmonids complicates efforts to evaluate the broader toxicological impacts to aquatic ecosystems. Our goals were to (1) validate the large range of in vivo species sensitivities reported for coho, Chinook, and sockeye salmon and (2) develop an in vitro platform for assessing 6PPDQ toxicity. In vivo studies confirmed the acute sensitivity of juvenile coho (12 h LC50 = 80.4 ng/L) and demonstrated that sockeye salmon were not vulnerable to mortality. Chinook salmon were sensitive to 6PPDQ mortality at initial concentrations >25 μg/L, ∼10-fold greater than reported environmental measurements. In vitro, the coho salmon cell line CSE-119 was acutely sensitive to 6PPDQ (metabolic EC50 = 7.9 μg/L, cytotoxicity EC50 = 6.1 μg/L). Analogous Chinook (CHSE-214) and sockeye salmon (SSE-5) cell lines were nonresponsive in both assays, and rainbow trout RTG-2 cells began showing metabolic effects at 68 μg/L (EC5). Recreation of species-specific 6PPDQ sensitivity in vitro implicates conserved modes of action in CSE-119 that could be utilized for mechanistic studies of 6PPDQ toxicity and screening of other PPD transformation products.

Secondary organic aerosols (SOAs) account for a large fraction of atmospheric fine particles, but the mechanisms of their formation and evolution processes remain unclear. In this study, a ground-based counterflow virtual impactor was used in combination with an online time-of-flight aerosol chemical speciation monitor to investigate the multiphase (gaseous and aqueous) oxidation processes and the SOA influencing factors during cloud events at a mountain site in southern China. Our results showed that the clouds promoted the formation of low-oxidized oxygenated organic aerosol (LO-OOA) and more-oxidized oxygenated organic aerosol (MO-OOA). At night, ozone (O3) and nitrate radicals (NO3•) oxidized volatile organic compounds (VOCs, mostly biogenic VOCs) to the precursors of LO-OOA and were absorbed in the cloud droplets to form LO-OOA, while the hydroxyl radical (•OH) was the main oxidant for LO-OOA during daytime. In the cloud droplets, LO-OOA was further oxidized by •OH to form MO-OOA. We propose that isoprene can be oxidized to form products in the gas phase and then absorbed by acidic cloud droplets to form 2-methylglyceric acid (2-MG), 2-MG-organosulfate, and 2-MG-organonitrate. This study improves our understanding of SOA formation, driven by multiphase oxidation during cloud events.

Natural organic matter (NOM) dominated electron transfer has been widely studied in wetlands, freshwater sediments, and peatlands, in which a diffusion-electron hopping mechanism consisting of dissolved organic matter (DOM) and particulate organic matter (POM) was found to mediate electron transfer over centimeter (cm) distances. However, it remains unclear whether such long-distance electron transfer also occurs when NOM is associated with minerals, which form organo-mineral associations (OMAs) and thus are less mobile and accessible. In this study, we investigated the roles of DOM and OMAs in transferring electrons by performing a series of microbial Fe(III)-mineral reduction experiments over a 2 cm distance. We found that significant electron transfer only occurred when both DOM and OMAs were present. Generally, we observed a positive correlation between the relative proportion of DOM and OMAs and the extent of Fe(III) mineral reduction. However, varying the proportion of DOM showed a stronger effect on the Fe(III)-mineral reduction compared to OMAs, indicating that DOM played a more critical role in the electron transfer network. Our findings shed new light on how organic carbon facilitates iron transformation and the associated biogeochemical cycling of nutrients and contaminants in forest soil systems.

Per- and polyfluoroalkyl substances (PFAS) pose risks to human health and ecosystems and are commonly found in wastewater treatment plant (WWTP) effluents discharged into surface waters. WWTPs continuously discharging PFAS into surface waters are hypothesized to lead to pervasive PFAS for downstream drinking water treatment plant (DWTP) intakes. To investigate the impact of this unplanned (de facto) wastewater reuse, we analyzed river water and WWTP effluent samples for 19 target PFAS and a surrogate chemical (sucralose) in a large watershed, with >165 WWTP discharges and multiple DWTP surface water intakes. The ∑PFAS concentrations of WWTP effluents (50–200 ng/L) were higher than that of the river water, with the same relative distributions of individual PFAS found in both samples. Surface water samples showed a direct and linear relationship between ∑PFAS and sucralose concentrations [∑PFAS (ng/L) = 0.0014 × (sucralose (ng/L)) + 19; R2 = 0.92] or predicted de facto reuse levels. Unplanned wastewater reuse could be a widespread source of PFAS for thousands of DWTPs. This study provides valuable guidance for future initiatives aimed at identifying sources of PFAS through de facto reuse modeling and chemical surrogate sampling.

There is growing interest in the transfer of micro- and nanoplastics (MNP) to the atmosphere from the ocean via sea spray, and a limited number of studies have quantified this emission. This study addresses the uncertainty surrounding existing global oceanic MNP emission estimates by developing an experimentally based emission parametrization. We conducted systematic laboratory experiments to understand the impact of MNP size, density, and concentration in water on their aerosolization. The results show that the MNP considered in this study, with a diameter of ≤10 μm, can be emitted via bubble bursting, with the aerosolization increasing monotonically with an increase in the concentration in water and decreasing with an increase in the particle size. Floating polyethylene MNP are observed to be less effectively aerosolized than polystyrene MNP dispersed in bulk water. Using the developed emission parametrization, we estimate that the upper limit of yearly MNP oceanic emission is 50.7 (14.2–93.4) quadrillion (1015) pieces year–1 and 1.66 (0.72–4.13) t year–1. The experimental measurements and ensuing parametrization developed in this study are a timely contribution to the atmospheric microplastic modeling community and will help in further constraining the oceanic source of atmospheric MNP and their potential climatic, environmental, and health implications.

A metagenomic survey predicted that some anaerobic methanotrophic archaea (ANME) belonging to the family Methanoperedenaceae can use formate as an alternative electron donor, although this process has yet to be experimentally verified. In this study, formate was fed to an enrichment culture dominated by a member of Methanoperedenaceae, Candidatus ‘Methanoperedens nitroreducens’. The culture indeed oxidized formate and reduced nitrate simultaneously in the absence or presence of methane. The fdhAB genes for formate metabolism were identified in the genome of Ca. ‘M. nitroreducens’, and RT-qPCR results showed their expression levels increased 2–6-fold when formate was consumed. This observation was in line with the results of metaproteomic analysis, which showed that the expression levels of formate dehydrogenase (FdhAB) was increased in the presence of formate. Together, the findings strongly suggested that formate can be an alternative electron donor for Ca. ‘M. nitroreducens’, revealing its versatile metabolic potential. As formate is a product or intermediate compound of many microbial processes, the capability to utilize formate could aid ANME in coping with the dynamic availability of methane in natural or anthropogenic environments. Our findings demonstrate the need for additional research on the feasibility of Ca. ‘M. nitroreducens’ and other ANME utilizing alternative electron donors other than methane.

The chemical nature and stability of reduced dissolved organic sulfur (DOSRed) have implications on the biogeochemical cycling of trace and major elements across fresh and marine aquatic environments, but the underlying processes governing DOSRed stability remain obscure. Here, dissolved organic matter (DOM) was isolated from a sulfidic wetland, and laboratory experiments quantified dark and photochemical oxidation of DOSRed using atomic-level measurement of sulfur X-ray absorption near-edge structure (XANES) spectroscopy. DOSRed was completely resistant to oxidation by molecular oxygen in the dark and underwent rapid and quantitative oxidation to inorganic sulfate (SO42–) in the presence of sunlight. The rate of DOSRed oxidation to SO42– greatly exceeded that of DOM photomineralization, resulting in a 50% loss of total DOS and 78% loss of DOSRed over 192 h of irradiance. Sulfonates (DOSSO3) and other minor oxidized DOS functionalities were not susceptible to photochemical oxidation. The observed susceptibility of DOSRed to photodesulfurization, which has implications on carbon, sulfur, and mercury cycling, should be comprehensively evaluated across diverse aquatic environments of differing DOM composition.

Firefighting training grounds (FTGs) may serve as a potential secondary source for the release of per- and polyfluoroalkyl substances (PFAS) due to historic use of aqueous film-forming foams (AFFFs). Understanding the heterogenicity and vertical distribution of PFAS in AFFF-impacted concrete is important for risk management and potential remediation. This study assessed whether desorption electrospray ionization mass spectrometry imaging (DESI MSI) can be used to analyze PFAS in a concrete core from an AFFF-impacted FTG to provide the vertical distribution of PFAS. PFOS and PFHxS were detected and observed to be distributed in the core mapped by DESI MSI in a manner consistent with data obtained using a conventional method of drilling samples along the depth of a concrete core (i.e., core sidewall drilling) followed by extraction into methanol and analysis by liquid chromatography mass spectrometry. Visualization by DESI MSI provided the mass distribution in greater detail at a resolution of 30–200 μm pixel size. DESI can provide location mapping at PFAS concentrations of >2.7 pg/mm2 (PFHxS) and 3.6 pg/mm2 (PFOS) with a spatial resolution much greater than that of the previously used core sidewall drilling method.

Surface ozone air pollution is unequally distributed in space and varies over urban and surrounding nonurban areas. Traditionally, urban ozone levels tend to be lower than their nonurban counterparts, resulting from discrepancies in emissions and nonlinearity in photochemistry. However, how the differences in urban vs nonurban ozone evolve over the past decades is uncertain. Here, we construct 6361 pairs of urban and nonurban ozone measurement sites based on available surface monitoring networks to analyze the long-term changes of their ozone differences. We show that urban vs nonurban ozone differences have narrowed substantially in North America, Europe, South Korea, and Japan over the summers of 1990–2020. The hemispheric mean urban vs nonurban ozone differences have decreased by 90% from −5.0 ppbv in the 1990s to −0.5 ppbv in the 2010s. We estimate that the anthropogenic emission reduction of nitrogen oxides is the dominant driver of the narrowing trends. It has suppressed the urban ozone titration and led to closer ozone formation regimes over urban and nonurban areas.