ASAP (As Soon As Publishable)

Mine tailings generated from hydrometallurgical processing of nickel–cobalt laterite deposits contain high levels of chromium (Cr), with the hexavalent species being a toxic pollutant and carcinogen. However, the partitioning, speciation, and local bonding environment of Cr in the mine tailings remain largely unknown, hindering our ability to predict its toxicity and long-term behavior. Coupling detailed mineralogical, spectroscopic, and geochemical characterization with sequential extraction of tailings from active and rehabilitated dams, we show that Cr is present in its least toxic form, Cr(III), and largely immobilized by recalcitrant minerals. This immobilization also regulates dissolved Cr concentrations in the interacting waters to levels up to five times lower than the global regulatory limit (50 μg L^–1). Solid-phase Cr concentrations were ≤1.5 wt % with 39–61% of Cr incorporated into hematite, and to a lesser extent, alunite, both of which formed early in the hydrometallurgical extraction process of mined laterite ores. The remaining Cr was present as recalcitrant chromite residues from the primary source laterites. We highlight that, although hydrometallurgical extractions liberate Cr from laterite ores during processing, they also provide ideal chemical pathways for the formation of highly stable, crystalline hematite that successfully sequesters Cr, while restricting its environmental mobility.

Most studies on the effects of organisms on microplastic characteristics have focused on microorganisms, while the impact of animal feeding behavior, particularly in aquatic species like fish and decapod crustaceans, has been less explored. This study examines how polyethylene spherical microplastics (275 μm in diameter) passing through the digestive tracts of crucian carp (Carassius carassius) and Australian crayfish (Cherax quadricarinatus) affect surface properties, particle size, and bacterial colonization. The species were fed diets with or without microplastics. The particles underwent two rounds of passage through the digestive tracts and were then exposed to known bacterial densities. Surface damage, size, and biofilm coverage were analyzed using scanning electron microscopy, while alterations in surface chemical composition were assessed through Fourier transform infrared spectroscopy with attenuated total reflectance, and the formation and penetration of nanoplastics in gut tissues and glands were determined using Py-GC/MS. Results show that the passage significantly altered surface properties and reduced microplastic size, without affecting chemical composition or nanoplastic penetration into tissues. These changes promoted bacterial colonization compared to controls. The findings suggest that animal feeding activity may play an important role in the mechanical fragmentation of microplastics in aquatic environments, potentially leading to their faster degradation.

Per- and polyfluoroalkyl substances (PFASs) with varying chain lengths, headgroups, and alternative structures are widespread and persistent in soil, yet knowledge of their biological effects and toxic mechanisms on soil microorganisms is limited. This study identified the structure-dependent impacts of PFAS on microbial fatty acid (FA) profiles by integrated field-laboratory investigations. The field investigation uncovered distinct PFAS-FA interaction patterns, varying by PFAS fluorocarbon (FC) chain length and functional group, and FA hydrocarbon (HC) chain length and unsaturation degree. Specifically, long-chain perfluoroalkyl carboxylic acids (PFCAs, FC7-17) increased medium/long-chain FAs (HC ≤ 17) and monounsaturated FAs (MUFAs), while long-chain perfluoroalkyl sulfonic acids (PFSAs, FC6-8) enhanced longer-chain FAs (HC > 17) and MUFAs. Additionally, perfluoroether carboxylic acids (PFECAs) as well as short-chain PFCAs (FC < 7) and PFSAs (FC < 6), which commonly used as alternatives to long-chain PFCAs/PFSAs, were associated with polyunsaturated FAs (PUFAs). The laboratory investigation with Pseudomonas aeruginosa PAO1 validated these FA metabolic disruptions and revealed broader perturbations in phospholipids, acetyl-CoA, and secondary metabolite metabolisms, providing insights into dysregulated membrane synthesis, C/N metabolisms, and bacteria quorum sensing (QS) processes. These findings reveal novel structure-dependent effects of PFASs on microorganisms, highlighting microbial FA profiles as potential metabolic biomarkers for assessing PFAS toxicity and soil health.

Arbuscular mycorrhiza (AM) often protect host plants from As accumulation under arsenic stress; however, the opposite is true for the As-hyperaccumulator Pteris vittata. With non-hyperaccumulator Pteris ensiformis as a comparison, the AM colonization, P and As uptake, and genes associated with As metabolism were investigated in P. vittata after growing 60-day with Rhizophagus irregularis inoculation under 0 (As₀), 10 (As₁₀), or 100 μM As (As₁₀₀) treatments. Based on the As-induced increase in AM colonization (up to 21%), AM symbiosis promoted P. vittata growth by 24% and frond P content by 22% in the AM+As₁₀₀ treatment than As₁₀₀ treatment. These increases corresponded to 4.2- to 5.4-fold upregulation in symbiotic P transporter RiPT1/7 in AM fungi and PvPht1;6 in P. vittata roots, which probably supported 37% greater As accumulation at 4980 mg kg^–1 in the fronds. Besides total As, enhanced arsenate reduction was evidenced by 19% greater arsenite and 15-fold upregulation of fungal arsenate reductase RiArsC in mycorrhizal roots. Further, the 2.1-fold upregulation of arsenite antiporters PvACR3/3;3 contributed to greater arsenite translocation to and sequestration in the fronds. Unlike P. ensiformis symbiont, which suffers from As stress, the mycorrhiza-specific P transporters (RiPT1/7 and PvPht1;6), arsenate reductases (RiArsC and PvHAC2), and arsenite antiporters (PvACR3/3;3) all benefited AM symbiosis and As accumulation in P. vittata.

The intestinal remodeling during amphibian metamorphosis is essential for adapting to various ecological niches of aquatic and terrestrial habitats. However, whether and how the widespread contaminant, perfluorobutanesulfonate (PFBS) affects intestinal remodeling remains unknown. In this study, tadpoles (Lithobates catesbeianus) at the G26 stage were exposed to environmentally relevant concentrations of PFBS (0, 1, 3, and 10 μg/L) until the end of metamorphosis. PFBS exposure resulted in reduced thyroid follicular glia; down-regulation of gene transcripts related to thyroid hormone synthesis; decreased blood hormone (corticotropin-releasing hormone, thyroid-stimulating hormone, and 3,5,3′-triiodothyronine (T3)) and transthyretin concentrations; and up-regulation of gene transcripts related to thyroid hormone degrading enzymes. Moreover, exposure to PFBS induced apoptosis in single-layer columnar epithelial cells, suppressed the proliferation of intestinal stem cells, and hindered their differentiation into adult epithelial cells during intestinal remodeling. The responses of Notch and Wnt signaling pathways regulated by T3 were downregulated, and key gene transcripts (msi, pcna, and lgr5) involved in intestinal remodeling regulated by these two pathways were also downregulated. This is the first report on the effects of PFBS on amphibian metamorphosis. Overall, PFBS reduced thyroid hormone synthesis and transport by interfering with the hypothalamic–pituitary–thyroid axis and transthyretin expression, inhibited downstream Notch and Wnt signaling pathway responses, and ultimately led to incomplete intestinal remodeling to some extent.

The export of terrestrial organic matter (TOM) to the ocean has been traditionally viewed to be minimal or only of significance in near-coastal continental margins. The broadly accepted explanation for the widespread loss of terrestrial lignin biomarkers and apparent disappearance of the <−25‰ stable carbon isotopic signature (δ¹³C) of TOM is that TOM is almost fully degraded before reaching the open ocean. Oceanic carbon (δ¹³C value ≥ −22‰) is therefore thought to be derived primarily from algae. However, an alternative explanation for the different molecular and δ¹³C signatures in terrestrial and marine environments may be that oxidative processing transforms TOM to appear marine-like. To test this hypothesis, we subjected eight TOM samples to a strong oxidation gradient. At carbon losses typical of TOM degradation during transport and sedimentation (above 60%), the differentiators of provenance disappeared, leaving a residue that was marine-like both chemically (aliphatic- and nitrogen-rich) and isotopically (δ¹³C enrichment of 4 to 9‰). This challenges the validity of conventional two-endmember mixing models, suggesting that a much larger fraction than previously estimated of the organic matter found in the ocean may originate from terrestrial sources, impacting global models of carbon cycling and sequestration.

The ozone micro–nano-bubble-enhanced oxidation (O₃MNBEO) technology has shown great potential for organics-contaminated groundwater remediation in laboratory studies. However, few studies addressed its effectiveness in engineering practices as well as the impact on the groundwater environment. In this study, a field demonstration was conducted to investigate the efficiency of O₃MNBEO in remediating groundwater contaminated by various organic compounds. The O₃MNBEO technology exhibited high removal efficiencies ranging from 85 to 100% for benzene and significantly reduced the concentration of naphthalene, toluene, and petroleum hydrocarbons in 5-day remediation. Groundwater remediation using the O₃MNBEO technology required less energy consumption and CO₂ emissions. Moreover, O₃MNBEO had no significant effect on groundwater pH and conductivity, and the oxidation–reduction potential (ORP) in groundwater and dissolved oxygen (DO) was substantially increased during the remediation process. The variations in ORP demonstrated a correlation with the contaminant concentration, which could serve as a potential indicator for assessing remediation progress. It is also worth noting that the presence of preferential seepage channels in the strata allows for the rapid migration of ozone MNBs, extending the reach of ozone MNBs. This study demonstrates that O₃MNBEO is an efficient, practical, green, and sustainable technology that can be applied to in situ remediation of organics-contaminated groundwater.

Abnormal development and mortality in early life stages pose significant threats to the growth and continuation of fish populations. Tris(2,4-di-tert-butylphenyl) phosphate (TDtBPP) is a novel organophosphate ester contaminant detected in natural waters. However, the potential effects of maternal exposure to TDtBPP on the early development of offspring embryos in fish remain unknown. Here, 30-day-old zebrafish were exposed to TDtBPP at 0, 50, 500, or 5000 ng/L for 180 days, and the exposed females were spawned with unexposed males. TDtBPP accumulation was detected in offspring embryos, accompanied by an increased malformation rate and mortality. The developmental abnormality of offspring embryos was identified to originate from the gastrula stage. Furthermore, based on transcriptome analysis, the down-regulation of RHO family interacting cell polarization regulator 2 gene (ripor2) was considered as a key toxic event, and this was confirmed in the subsequent knockdown experiment. Moreover, molecular docking studies and forkhead box O1 (foxO1) transcription factor inhibitor (AS1842856) exposure experiments demonstrated that the blockade of foxO1 transcriptional regulation was responsible for the decreased expression of ripor2. The results of this study demonstrated that the occurrence of developmental malformation and mortality in zebrafish offspring embryos following maternal TDtBPP exposure were triggered by the blockade of foxO1 transcriptional regulation and the consequent down-regulation of ripor2.

Per- and polyfluoroalkyl substances (PFAS) make up a class of highly toxic and persistent chemicals that have been widely detected in different environmental matrices. Recently, various hydrated electron-based techniques have been developed to destroy these compounds. However, the molecular mechanisms controlled by different hydrated electron photosensitizers are still unclear. Herein, we investigated the PFAS transformation processes in different hydrated electron-based systems, i.e., UV/Na₂SO₃, UV/indole, and UV/3-indoleacetic acid (IAA), using different perfluorocarboxylic acids (PFCA) as model compounds. By monitoring the production and decay of hydrated electrons, molecular interactions, and the generated intermediates, we systematically revealed the structure-property-performance mechanism of different systems. In the UV/Na₂SO₃ system, the disordered attack of hydrated electrons induced rapid destruction for either long or short-chain PFCA. However, the lower hydrated electron efficiency limited the final defluorination ratio. In the UV/indole system, the interaction between indole and PFCA promoted the directed transfer of hydrated electrons, resulting in a significantly higher destruction efficiency for long-chain PFCA than for short-chain PFCA. However, the self-quenching of hydrated electrons in the UV/IAA system led to the ineffective decomposition for all PFCA. This study provides mechanistic insights into the hydrated electron-induced PFAS decomposition processes, which would expand the designing strategies for improving PFAS destruction efficiency.

Fine particulate matter (PM_2.5) is linked to dementia risk, but ultrafine particles (UFPs, <100 nm) may be even more toxic due to their distinct physicochemical properties. However, evidence on UFPs and dementia remains limited. This study assessed the association between UFP exposure and Alzheimer’s disease (AD) and related dementias (ADRD) among U.S. older adults. Using Medicare data, we analyzed ZIP code-level UFP exposure in 2017 for beneficiaries aged 65 and older residing in the contiguous U.S., applying Cox proportional hazard models to estimate AD and ADRD incidence (2018–2020) while considering comorbidities. Among ∼21 million participants for AD and ∼20 million for ADRD, each interquartile range increase in UFP exposure (3701.6 and 3668.5 particles/cm³, respectively) was associated with higher AD (HR: 1.026, 95% CI: 1.014–1.038) and ADRD (HR: 1.016, 95% CI: 1.008–1.023) risks. The association was linear within typical exposure levels and stronger in individuals with comorbidities. Geographically, the UFP-associated dementia risk was higher in rural areas than in urban areas, possibly due to different pollution sources. These findings underscore UFPs as neurotoxicants and highlight the need for targeted public health interventions to protect vulnerable populations.

Chronic wasting disease (CWD) is a fatal neurodegenerative disease affecting cervids. CWD is caused by infectious prions, which can enter the environment through bodily fluids or the carcasses of infected animals. Prions can be stored, remain infectious in both soil and water for many years, and transported hydrologically, possibly expanding the geographic range of CWD transmission. In order to better predict hydrological prion transport, we investigated how CWD prion protein (PrP^CWD) partitions and persists in environmental waters. We performed PrP^CWD spike experiments with water samples containing fine sediments from two locations within a CWD-contaminated site, at which contamination sources were removed one year prior. Samples were filtered after spiking, and filtrates and sediments were tested separately for PrP^CWD using real-time quaking-induced conversion (RT-QuIC). Unspiked filtrates tested negative for PrP^CWD, while unspiked sediments were positive, indicating PrP^CWD persistence in environmental sediments for at least one year. Spiked sediments were positive immediately after spiking and throughout 28 days of incubation. Spiked filtrates were largely negative immediately after spiking and remained negative for 28 days, with some inconsistent positives from one sampling location. Our results indicate that PrP^CWD readily partitions to the sediment fraction of environmental waters, suggesting that hydrological prion transport is sediment-facilitated.

Reduced chromite ore processing residue (rCOPR) is vulnerable to the surrounding conditions in environments, which can induce the release and oxidation of Cr(III). This work found the synergistic effect of light and sulfite on destroying rCOPR stability, causing the significant release of Cr(VI), which was 4∼7 times higher than that under single factor action. In Cr_xFe_1–x(OH)₃/sulfite/light system, Cr(VI) release rate could reach 11.11 × 10^–7 M min^–1 g^–1, because of the rapid formation of ·OH, O₂^·–, SO₄^·–, and quadrivalent iron [Fe(IV)]. In addition, this study found that the oxidized chromium residue could continuously release Cr(III) after being transferred to the dark environment. This should be attributed to the obvious change in the iron coordination structure of rCOPR caused by the catalytic reaction of sulfite with light, which greatly weakened the ability of the Fe–O structure to encase chromium elements in a solid. These insights are crucial for predicting the environmental risks of rCOPR in the presence of visible light and sulfur-containing compounds.

Medium-chain chlorinated paraffins (MCCPs) are among the most prevalent chemicals detected in human serum. As an emerging persistent organic pollutant, their toxicity mechanisms, particularly concerning the female reproductive system, remain poorly understood. In this study, we present both in vivo and in vitro evidence of ovarian toxicity induced by MCCPs and insights into their underlying molecular mechanisms. MCCP exposure induced chromatin condensation in the nucleus and mitochondria vacuolization of ovarian granulosa cells in rats and significantly increased the levels of serum gonadotropins and sex hormones, while reducing gonadotropin-releasing hormone levels. Transcriptomics analysis of ovaries revealed a predominant effect of MCCPs on the cell cycle, oocyte meiosis, and DNA damage repair pathways. Moreover, dual-omics integrative analysis indicated significant disturbance of steroid hormone biosynthesis caused by MCCPs, as well as amino acid metabolism related to TCA cycle. Furthermore, in vitro assays demonstrated that MCCP exposure disrupts intracellular Ca²⁺ homeostasis and generates reactive oxygen species, ultimately leading to DNA damage. In conclusion, this study revealed potential mechanisms by which MCCPs affect ovary function. These findings can provide valuable insights for the mechanism-based risk assessment of MCCPs on female reproduction.

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) are frequently detected in humans. However, information regarding their metabolites is still very limited. Herein, target analysis and halogenation-guided nontarget and suspect screening were conducted on serum samples using UHPLC-Orbitrap-HRMS. The median concentrations of SCCPs and MCCPs were 7.76 and 4.31 ng/mL, respectively. A series of hydroxylated chlorinated paraffins (OH-CPs) were tentatively identified with an estimated average concentration of 1.80 ng/mL, which was approximately 9.9% of the total SCCPs and MCCPs. A chlorine distribution shift was observed from chlorinated paraffins (CPs) dominated by Cl₆ and Cl₇ to OH-CPs dominated by Cl₅, Cl₆, and Cl₄. In human liver cytochrome P450 (CYP) enzyme incubation assays, the CPs in commercial mixtures were mainly metabolized into OH-CPs with various carbon lengths and chlorine substituents. The results obtained from human serum and in vitro experiments suggested the oxidative metabolism of SCCPs and MCCPs in humans. The metabolic pathways were then comprehensively explored using a CP monomer (1,1,1,3,10,11-hexachloroundecane) incubated with the same CYP enzymes, demonstrating that CPs can be metabolized through successive oxidative dechlorination and direct hydroxylation, with subsequent oxidation to carboxylic acids. Further studies should focus on the long-term toxicity of OH-CPs.

This study hypothesized that perfluorooctanesulfonate (PFOS) exposure disrupts maternal-fetal metabolism, affecting fetal liver hematopoietic stem cell (FL-HSC) development. Pregnant mice received PFOS (0.3 and 3 μg/g bw) and were sacrificed on gestation day 14.5. Metabolomic analysis of maternal plasma revealed disruptions in steroid hormone, purine, carbohydrate, and amino acid metabolism, which aligned with the enriched pathways in amniotic fluid (AF). FL analysis indicated increased purine metabolism and disrupted glucose and amino acid metabolism. FL exhibited higher levels of polyunsaturated fatty acids, glycolytic and TCA metabolites, and pro-inflammatory cytokine IL-23, crucial for hematopoiesis regulation. Transcriptomic analysis of FL-HSCs revealed disturbances in the PPAR signaling pathway, pyruvate metabolism, oxidative phosphorylation, and amino acid metabolism, correlating with FL metabolic changes. Metabolomic analysis indicated significant rises in glycerophospholipid and vitamin B6 metabolism related to HSC expansion and differentiation. Flow cytometric analysis confirmed increased HSC populations and progenitor activation for megakaryocyte, erythrocyte, and lymphocyte lineages. The CFU assay showed a significant increase in BFU-E and CFU-G, but a decrease in CFU-GM in FL-HSCs from the H-PFOS group, indicating altered differentiation potential. These findings provide for the first time insights into the effects of PFOS on maternal-fetal metabolism and fetal hematopoiesis, highlighting implications for pollution-affected immune functions.

This study investigates the impacts of wildfires on nanoparticle characteristics and exposure disparities in Toronto, integrating data from a large-scale mobile monitoring campaign and fixed-site measurements during the unprecedented 2023 wildfire season. Our results reveal changes in particle characteristics during wildfire days, with particle number concentrations decreasing by 60% and particle diameter increasing by 30% compared to nonwildfire days. Moreover, the median lung deposited surface area (LDSA) levels rose by 31% during wildfire events. We employed gradient boosting models to estimate near-road LDSA levels on both wildfire and nonwildfire days. The LDSA ratio (wildfire/nonwildfire) exceeded 2.0 in certain areas along highways and in downtown Toronto. Furthermore, our findings show that marginalized communities faced greater LDSA increases than less marginalized ones. Under wildfire conditions, the LDSA ratio difference between the most and least marginalized groups was 16% for recent immigrants and visible minorities and 7% for seniors and children, both statistically significant. This study delivers critical insights into the spatiotemporal variations of nanoparticle characteristics during wildfire and nonwildfire periods, demonstrating the substantial health risks posed by increased LDSA levels and the inequitable distribution of these risks among Toronto’s diverse population.

Sludge is a biohazardous solid waste that is produced during wastewater treatment. It contains antibiotic resistance genes (ARGs) that pose significant antimicrobial resistance (AMR) threats. Herein, aerobic and anaerobic membrane bioreactors (AeMBRs and AnMBRs, respectively) were compared in terms of the volume of waste sludge generated by them, the presence of ARGs in the sludge, and the potential for horizontal gene transfer (HGT) events using metagenomics to determine which treatment process can better address AMR concerns associated with the generation of waste sludge. The estimated abundance of ARGs in the suspended sludge generated by the AnMBR per treated volume is, on average, 5–55 times lower than that of sludge generated by the AeMBR. Additionally, the ratio of potential HGT in the two independent runs was lower in the anaerobic sludge (0.6 and 0.9) compared with that in the aerobic sludge (2.4 and 1.6). The AnMBR sludge exhibited reduced HGT of ARGs involving potential opportunistic pathogens (0.09) compared with the AeMBR sludge (0.27). Conversely, the AeMBR sludge displayed higher diversity and more transfer events, encompassing genes that confer resistance to quinolones, rifamycin, multidrug, aminoglycosides, and tetracycline. A significant portion of these ARGs were transferred to Burkholderia sp. By contrast, the AnMBR showed a lower abundance of mobile genetic elements associated with conjugation and exhibited less favorable conditions for natural transformation. Our findings suggest that the risk of potential HGT to opportunistic pathogens is greater in the AeMBR sludge than in AnMBR sludge.

The relationship between the socioeconomic status (SES) and PM_2.5 exposure is rather inconclusive. We employed taxi-based measurements with 30 m resolution to characterize PM_2.5 exposure with local source contribution (PM_2.5 adjusted concentration) discerned for 2019 winter and 2020 summer, in Xi’an. A big data set comprising ∼6 × 10⁶ hourly PM_2.5 measurements and SES data from ∼5000 communities was utilized to examine the socioeconomic inequalities in community-level PM_2.5 exposure. Our results indicate that the inhabitants with lower SES are more likely to be disproportionately exposed compared to those with higher SES. At least 92% of disproportionately exposed inhabitants in rural regions reside in low SES areas, whereas a relatively smaller proportion (69–78%) reside in urban regions. The local source has a more profound impact on PM_2.5 exposure during summer than winter. The inhabitants in polluted areas and low PM_2.5 adjusted concentration areas accounted for 22% and 26% of total PM_2.5 exposure during the winter. However, inhabitants residing in low-concentration areas contributed only 12% of total exposure during summer while those polluted areas contributed 30%. These findings provide valuable insights into the relationship between community-level PM_2.5 exposure and SES, highlighting the need for more sophisticated air quality policies to alleviate socioeconomic inequalities in PM_2.5 exposure.

Catalyst deactivation poses a significant challenge in environmental remediation, especially for the photocatalytic oxidation of chlorinated volatile organic compounds (Cl–VOCs). In this study, a functional flower-like TiO₂@Mn/rGO (FTMG) catalyst coupled with a vacuum ultraviolet (VUV) lamp was used as a novel photocatalytic oxidation (VUV–PCO) system for chlorobenzene (CB) oxidation. In this system, more than 80% of CB was efficiently oxidized at a high w8 hly space velocity of 600,000 g_cat^–1 h^–1, which was a 6.5-fold increase compared to conventional UV–PCO, and no catalytic deactivation over 1300 min of reaction. Notably, the CO_x selectivity consistently reached 100%. These outstanding performances were attributed to the synergy of direct VUV photolysis and gas–solid interface photocatalysis. Importantly, the C–Cl bond of CB was efficiently cleaved by VUV photolysis, generating ^•Cl as the oxidant. Ozone (O₃) generated from VUV photolysis was efficiently adsorbed on oxygen vacancies and Mn (O_v + Mn) adjacent sites on FTMG. These adsorbed O₃ rapidly captured the photogenerated electrons, thereby effectively preventing Cl reduction and avoiding catalyst deactivation. This study sheds light on the unique dechlorination reaction and Cl-poisoning-resistance mechanism in the VUV–PCO system, offering a novel strategy to boost the catalytic oxidation of Cl–VOCs.

Lithium is a critical material for the energy transition, but its mining causes significant environmental impacts that will intensify due to surging global demand. Here, we conduct a mining site-specific environmental impact assessment of lithium on a global scale, focusing on greenhouse gas (GHG) emissions, water use, and land use. We then track the production and international trade flows of all lithium-containing commodities to assess how lithium mining impacts are distributed across global supply chains. Results indicate that environmental impact intensities of battery-grade Li₂CO₃ production from various mine sites differ between 4 times for GHG emissions to 2885 times for land use. 56–68% of environmental impacts generated in the mining countries were embodied in internationally traded lithium flows. On the production side, China, Australia, and Chile were the top 3 countries, accounting for 91–94% of environmental impacts. Regarding final demand, China was the major consuming region, inducing 46–47% of the environmental impacts of global lithium mining, followed by Korea (17–18%) and the EU-27 (9%). Our findings reveal the need for spatially explicit information to accurately assess the environmental impacts of lithium mining and highlight that mitigation requires cooperation between major producer and consumer countries.

Mercury emission from coal combustion flue gas is a significant environmental concern due to its detrimental effects on ecosystems and human health. Elemental mercury (Hg⁰) is the dominant species in flue gas and is hard to immobilize. Therefore, it is necessary to comprehend the reaction mechanisms of Hg⁰ oxidation, namely, Hg⁰ to oxidized mercury (Hg²⁺), for mercury immobilization. In spite of extensive research on homogeneous Hg⁰ oxidation, universal accurate prediction models and unified explanations are lacking. In this study, for the first time, quantitative prediction models were developed for the Hg⁰ oxidation percentage with machine learning (ML) using flue gas compositions and operating conditions as inputs. Gradient boosting regression models showed optimal performance (test R² ≥ 0.85). ML-aided feature analysis results exhibited that Cl₂, HCl, Hg⁰, temperature, and HBr were the top five critical factors affecting mercury homogeneous oxidation. Halogen gas promoted Hg⁰ oxidation at temperatures around 250 °C, while Hg⁰, SO₂, and quench rates were not conducive to Hg⁰ oxidation. High reaction rate coefficients for the Hg/Cl and Hg/Br reactions verified the ML interpretive results and revealed the major mercury homogeneous oxidation mechanisms. Models developed here may play important roles in understanding Hg⁰ oxidation and optimizing flue gas Hg immobilization technologies.

Despite the widespread use of reverse osmosis (RO) membranes in water desalination, the role of solute–membrane interactions in solute transport remains complex and relatively not well understood. This study elucidates the relationship between solute–membrane electrostatic interactions and solute permeability in RO membranes. The transport of salt and neutral molecules through charged polyamide (PA) and uncharged cellulose triacetate (CTA) RO membranes was examined. Results show that salt rejection and salt permeability in the PA membrane are highly dependent on the solution pH due to the variations of membrane charge density and the Donnan potential at the membrane–solution interface. Specifically, a higher salt rejection (and hence lower salt permeability) of the PA membrane is observed under alkaline conditions compared to acidic conditions. This observation is attributed to the enhanced Donnan potential at higher solution pH, which hinders co-ion partitioning into the membrane. In contrast, for salt transport through the CTA membrane and neutral solute transport through both membranes, solute permeability is independent of the solution pH and solute concentration due to the negligible Donnan effect. Overall, our results demonstrate the important role of solute-membrane electrostatic interactions, combined with steric exclusion, in regulating solute permeability in RO membranes.

Exposure to air pollutants, especially fine particulate matter (PM_2.5), has been recognized as a major contributor to the increasing prevalence of kidney diseases. However, until now, evidence for the translocation of airborne nanoparticles (NPs) in the human kidney has been lacking, hindering the understanding of the relationships between PM_2.5 exposure and kidney diseases. Here, we report the discovery and analysis of airborne magnetite nanoparticles in human kidney stones (with mass concentrations ranging from 363 to 740 ng/g dry tissue weight) by high-resolution microstructural characterization. Notably, we established a methodology for highly selective extraction and accurate characterization of distinctive magnetite NPs and identified the abundant presence of these NPs with a distinctive core–shell structure of Fe₃O₄/SiO₂ in both kidney stones and human blood. We demonstrate that such distinctive core–shell magnetite NPs are indicative of a coal-burning source. Hence, magnetite NPs deposited in the human kidneys in this study area most likely derived from air pollution emissions from coal-fired power plants and were transported via blood circulation to the kidney. Our results provide compelling evidence for understanding the systemic health risks of exposure to nanoparticulate, Fe-bearing air pollution and the associations observed between kidney diseases and PM_2.5 exposure.

Pelletization of biomass fuels has been promoted as an effective alternative to mitigate particulate matter (PM) emissions from the residential burning of raw biomass materials; however, environmentally persistent free radicals (EPFRs), a class of harmful components in PM, from the biomass pellet burning have been rarely studied yet. Here, laboratory-based combustion experiments were conducted to characterize EPFRs for different pellets burned in cooking and heating stoves and compared with those for the corresponding uncompressed biofuels. Emission factors (EFs) of EPFRs for biomass pellets ranged from 2.97 × 10¹⁷ to 2.33 × 10¹⁹ spins/kg, following a log-normal distribution, with a geometric mean of 4.21 × 10¹⁸ spins/kg. These EPFRs were carbon-centered free radicals adjacent to oxygen atoms. Emissions varied largely across different fuel–stove combinations, with the combustion efficiency and combustion temperature as key influencing factors explaining 49% of the variations in EFPR EFs. Compared to raw fuels, pelletized fuels showed 50–80% lower EPFR EFs and 40–70% lower EPFRs per PM but more different EPFR types, and there was no significant change in the degree of oxidation of the EPFRs. The burning of pellets made from crop residues in a clean cookstove can reduce nearly 90% EFPRs from the raw biomass burning, which is different from the reduction degree in PM mass. This study provides valuable data in promoting the understanding of EPFR formation and deployment of biomass pellets in the protection of air quality and human health.

Humic-like substances (HULIS) widely exist in the atmosphere and may strongly affect human health, environment, and climate. However, there are still no accurate methods for detecting the vertical distribution of HULIS. Here, a Raman-Polarization-Fluorescence Spectroscopic Lidar (RPFSL) was developed to simultaneously measure 64-channel broad fluorescence spectra (370–710 nm) of atmospheric aerosols at an excitation wavelength of 355 nm. The study revealed that dust could be coated by abundant fluorescent substances, with a maximum fluorescence efficiency reaching 0.15. Moreover, the fluorescent spectra of air pollutants exhibited a unimodal structure, while the spectra of dust exhibited three peaks, suggesting that they may be useful for highly accurate identification of dust aerosols from other aerosols. The findings in this study were confirmed by near-ground air sampling analysis based on fluorescence excitation–emission matrix-parallel factor (EEM-PARAFAC) methods; we demonstrated that HULIS and protein-like organic matter (PLOM) were the main components of fluorescent aerosols during the study period. During air pollution events, the number concentration of HULIS reached up to 9699 particles·m^–3. For the first time, this study proposes a real-time, high-resolution method for detecting height-resolved HULIS, significantly helping to evaluate the environmental and health implications of HULIS.

Despite decades of emission control measures aimed at improving air quality, Los Angeles (LA) continues to experience severe ozone pollution during the summertime. We incorporate cooking volatile organic compound (VOC) emissions in a chemical transport model and evaluate it against observations in order to improve the model representation of the present-day ozone chemical regime in LA. Using this updated model, we investigate the impact of adopting zero-emission vehicles (ZEVs) on ozone pollution with increased confidence. We show that mitigating on-road gasoline emissions through ZEV adoption would benefit both air quality and climate by substantially reducing anthropogenic nitrogen oxides (NO_x) and carbon dioxide (CO₂) emissions in LA by 28 and 41% during the summertime, respectively. This would result in a moderate reduction of O₃ pollution, decreasing the average number of population-weighted O₃ exceedance days in August from 9 to 6 days, and would shift the majority of LA, except for the coastline, into a NO_x-limited regime. Our results also show that adopting ZEVs for on-road diesel and off-road vehicles would further reduce the number of O₃ exceedance days in August to an average of 1 day.

This study explores the correlation of contaminants of emerging concern (CECs) in wastewater effluents using liquid chromatography (LC), supercritical fluid chromatography (SFC), and comprehensive two-dimensional gas chromatography (GC × GC) with derivatization, all coupled to high-resolution mass spectrometry (HRMS). Over 300 compounds, including frequently overlooked highly polar and nonpharmaceutical CECs, were identified. Monitoring programs mainly focus on reducing variability and assessing pollution in wastewater treatment plant (WWTP) effluents under dry weather conditions, often neglecting wet-weather discharges. In this study, correlation analysis revealed the complex impact of rainfall on wastewater effluent composition, identifying clusters of CECs introduced through rain runoff and discharges from retention basins. Rain events affected the removal efficiency of easily degradable CECs, with variations between WWTPs. Persistent compounds such as PFAS demonstrated strong intragroup correlations, reflecting their common sources and environmental stability. These findings provide valuable insights into the diverse profiles of CECs in wastewater and demonstrate the potential of correlation-based approaches to optimize treatment strategies to the specific challenges of individual WWTPs.

Persistent free radicals (PFRs) have garnered considerable attention due to their long lifetime and high reactivity. However, the roles of photogenerated carriers in PFR formation remain underexplored. We compared and analyzed the PFR formation on hematite-SiO₂ loaded catechol, combining experimental and theoretical investigations. Significant PFRs were observed only under ultraviolet light irradiation. The PFR concentration on hematite nanoplates (HP, 1.29 × 10¹⁷ spins/mg) was higher than those on hematite nanocubes (HC, 9.19 × 10¹⁶ spins/mg) and nanorods (HR, 7.02 × 10¹⁶ spins/mg). A stronger stability of PFRs on HR (183 h of t_1/e) was observed compared with HP (95.4 h of t_1/e) and HC (37.7 h of t_1/e). Photoelectrochemical analysis and quenching experiments indicated that photogenerated holes, rather than electrons, controlled the PFR formation. Photogenerated holes manipulate the asymmetric distribution of up-spin and down-spin electrons in the p orbital of catechol to regulate PFR formation. Hole quantity and exposed facets caused significant differences in the concentration and stability of PFRs. The high concentration of PFRs on HP is due to abundant holes, while the weak stability of PFRs on HC is due to the exposed {012} facet. This study introduces a novel mechanism for PFR formation regulated by photogenerated holes, contributing to a better understanding of their environmental function and associated risks.

Per- and polyfluoroalkyl substances (PFAS) are recalcitrant contaminants of emerging concern. Research efforts have been dedicated to PFAS microbial biotransformation in the hopes of developing treatment technologies using microorganisms as catalysts. Here, we performed a meta-analysis by extracting and standardizing quantitative data from 97 microbial PFAS biotransformation studies and comparing outcomes via statistical tests. This meta-analysis indicated that the likelihood of PFAS biotransformation was higher under aerobic conditions, in experiments with defined or axenic cultures, when high concentrations of PFAS were used, and when PFAS contained fewer fluorine atoms in the molecule. This meta-analysis also documented that PFAS biotransformation depends on chain length, chain branching geometries, and headgroup chemistry. We found that the literature is scarce or lacking in (i) anaerobic PFAS biotransformation experiments with well-defined electron acceptors, electron donors, carbon sources, and oxidation–reduction potentials, (ii) analyses of PFAS biotransformation products, and (iii) analyses to identify microorganisms and enzymes responsible for PFAS biotransformation. To date, most biotransformation research emphasis has been on 8:2 fluorotelomer alcohol (8:2 FTOH), 6:2 fluorotelomer alcohol (6:2 FTOH), perfluorooctanesulfonic acid (PFOS), and perfluorooctanoic acid (PFOA). A wide array of PFAS remains to be tested for their potential to biotransform.

The catalytic effect of aqueous Fe(II) (Fe²⁺_aq) on the transformation of Fe(oxyhydr)oxides has been extensively studied in the laboratory. It involves the transfer of electrons between Fe²⁺_aq and Fe-(oxyhydr)oxides, rapid atomic exchange of Fe between the two states, and recrystallization of the Fe-oxides into more stable Fe-(oxyhydr)oxides. The potential occurrence of these reactions in natural soils and sediments can have an important impact on biogeochemical cycling of iron, carbon, and phosphorus. We investigated the possible isotopic exchange between Fe²⁺_aq and sedimentary Fe(III) in Fe–Si–C-rich lake sediments. ⁵⁷Fe Mössbauer spectroscopy was used to evaluate Fe mineral speciation in unaltered lake sediments. Unaltered and oxidized sediment laboratory incubations were coupled with a classical kinetic approach that allows a quantitative description of the reactivity of assemblages of Fe-(oxyhydr)oxides found in sediments. Specifically, unaltered and oxidized sediment samples were separately incubated with an ⁵⁵Fe²⁺_aq-enriched solution and exchange was observed between ⁵⁵Fe²⁺_aq and sedimentary Fe(III), highest in the top of the sediment and decreasing with depth with the ⁵⁵Fe²⁺_aq tracer distributed within the bulk of the sedimentary Fe(III) phase. Our results indicate that atomic exchange between Fe²⁺_aq and sedimentary Fe(III) occurs in natural sediments with electrons transferred from the Fe(III)-particle to Fe(III)-particle via Fe²⁺_aq intermediates.

Microplastics (MPs) are known to affect soil carbon stability in a numerous ways. However, the mechanisms by which they alter the carbon stability within soil aggregates remain unclear . Herein, a one-year field experiment was conducted in an arid agricultural region employing stable isotope techniques to evaluate the soil organic carbon flow in the presence of both persistent (PE, PVC) and biodegradable (PLA, PHA) MPs. PE and PVC reduced the stability of soil aggregates, while PLA and PHA maintained it. Additionally, organic carbon content increased in microaggregates but decreased in small macroaggregates for PE and PVC treatments. By contrast, treatment with PLA and PHA enhanced organic carbon content across aggregates. The δ¹³C values of PE- and PVC-treated aggregates ranged from −25.34 to −20.85‰, while those of PLA and PHA ranged from −16.29 to −9.26‰. Notably, MPs altered the direction of carbon flow between aggregates, reduced carbon flux, and accelerated carbon emissions. RFP and PLS–PM analyses revealed that persistent MPs affected carbon flow primarily via abiotic factors, whereas biodegradable MPs influenced it via biotic factors. These findings provide insights into the mechanisms by which MPs impact aggregate-associated carbon, highlighting their effects on soil ecosystem services.

Urban greenspace (UGS) is a crucial nature-based solution for mitigating increasing human exposure to extreme heat, but its long-term potential has been poorly quantified. We used high spatial-temporal resolution data sets of urban land cover and population grid in combination with an urban climate model, machine learning, and land use simulation model to assess the impact of UGS on population exposure to extreme (high-heat exposure, HHE) and its potential spatial optimization strategies. Results showed that the UGS and HHE have a strong spatiotemporal dynamic coupling in 21st century Chinese cities. Moreover, UGS shrinkage increased the HHE by 0.58–1.15 °C, while UGS expansion mitigated it by 0.72–1.26 °C, both stronger in the SSP3–7.0 and SSP5–8.5 scenarios. Different from common impressions, spatial relationships, rather than quantities of UGS, are more influential (1.3–1.8 times) on HHE. Our solutions suggest that simply enhancing the spatial dynamic connectivity between patches can mitigate HHE by 9.1–21.1%, especially for the eastern and central cities. Our results provide an example of how to improve climate adaptation in urban ecological space designs and strongly promote research on optimal spatial patterns for future robust urban heat mitigation.

Since the end of nuclear weapon testing, anthropogenic metallic radionuclides have originated from nuclear accidents such as Chernobyl and Fukushima and controlled releases from the nuclear industry. ⁶⁰Co is an activation product found in the effluents of nuclear power plants, mobile nuclear reactors, and fuel reprocessing facilities. In this paper, we are addressing the question of (radio)cobalt speciation upon bioaccumulation in the sentinel organism Mytilus galloprovincialis after in vivo contamination in a pseudo-natural system. For this study, inductively coupled plasma mass spectrometry and gamma spectroscopy were used to quantify the cobalt distribution in the various organs: hepatopancreas, gills, visceral mass, mantle, foot, and byssus, as well as in subcellular compartments. Two X-ray spectroscopic techniques were used to decipher cobalt speciation and localization, bulk X-ray absorption spectroscopy (XAS with EXAFS and XANES regimes), and micro X-ray fluorescence imaging (μ-XRF). Lastly, secondary ion mass spectrometry images provided information on cobalt distribution at a subcellular scale. The accumulation of cobalt exhibits significant differences depending on the origin of the individuals, with higher concentration factor values for mussels from the Toulon Naval Base (considered as polluted) compared to Villefranche sur Mer, France (considered as unpolluted). However, concentration in organs always follows the same order: byssus ≫ hepatopancreas ≫ other organs. In terms of spatial distribution, cobalt has been visualized in the hepatopancreas, revealing the presence of preferred zones within some digestive cells and this could be linked to detoxification mechanisms. Finally, the determination of speciation data using XAS suggested the presence of a Co(II)-metallothionein complex in the hepatopancreas and a potential Co(II)-mfp-1 complex in the byssus. While they can be challenging, accumulation and speciation studies in radioecology are essential steps for a comprehensive approach to the impact of trace metallic radionuclides on the marine biota.

Halogenated antibiotics pose a great threat to aqueous environments because of their persistent biotoxicity from carbon–halogen bonds. Electrochemical reduction (ER) is an efficient technology for dehalogenation, but it still suffers from limited efficiencies in breaking C–F bonds. Herein, we present a strategy to enhance C–F cleavage and promote detoxification by loading benchmark palladium cathodes onto boron-doped carbon. This improves the florfenicol (FLO) degradation rate constant and defluorination efficiency by 1.24 and 1.05 times, respectively, and improves the defluorination of various fluorinated compounds. The cathode with optimal B content shows superior mass activity for FLO degradation (1.11 mmol g^–1 Pd min^–1), which is 5.9 times that of commercial Pd/C and is among the best-reported cathodes. Notably, the exclusive formation of the direct defluorination product (i.e., FLO-F) on Pd/B–C implies a higher intrinsic C–F cleavage ability endowed by B doping. As revealed by experiments and theoretical calculations, boron modification enhances palladium binding and induces stronger strain effects and higher electron density for surface palladium atoms, which boosts H* generation and reduces the energy barrier for C–F cleavage. This study provides an effective cathode design strategy to enhance C–F activation, which may broadly benefit the destruction and detoxification of fluorinated organics that are limited by sluggish C–F cleavage kinetics.

Nanofiltration membranes attract extensive attention in solute selective separation, especially in resource extraction and recovery. A prevalent strategy to enhance the monovalent and multivalent ion selective separation performance involves modifying the membrane surface charge properties to influence the Donnan exclusion. However, the counterion adsorption and shielding effects are aggravated with increasing ionic strength, which severely weaken the Donnan exclusion. This study revealed that the contribution of Donnan exclusion was fairly moderate to SO₄^2– rejection in high salinity solutions, while it was dielectric exclusion that exerted the most important influence on Cl^–/SO₄^2– selective separation with a pore radius at 0.35–0.44 nm (molecular weight cutoff at 180–300 Da). Consequently, we proposed that tailored design of nanofiltration membranes with a precise pore radius to fully utilize the steric and dielectric exclusion instead of increasing membrane charge density is more crucial for monovalent/multivalent ion selective separation in high salinity solutions. Overall, our study reveals the importance of dielectric exclusion and provides new insights into nanofiltration membrane customization and application for ion selective separation in high salinity solutions.

Loose nanofiltration (LNF) membranes with high permeance and separation selectivity are highly desired for the effective separation of organic dyes and inorganic salts. Herein, a novel polyamide LNF membrane was fabricated using zwitterionic amine reactant trimethylamine N-oxide-based polyethylenimine (TPEI) and trimesoyl chloride (TMC) via interfacial polymerization (IP). A thin, loose, and smooth polyamide layer was formed due to the low diffusion rate and modified chemical structure of TPEI. The optimized membrane (NF-TPEI) exhibited an extremely high water permeance of 213.0 L m^–2 h^–1 bar^–1, accompanied by outstanding dye rejections of Congo Red (99.8%), Coomassie Brilliant Blue R250 (99.5%), and Evans Blue (99.9%). Meanwhile, the membrane possessed low rejections (<7.0%) of inorganic salts (Na₂SO₄, MgSO₄, MgCl_2, and NaCl). Additionally, the NF-TPEI membrane exhibited outstanding antifouling performance, achieving a superior recovery ratio of 96.0 and 98.1% after the filtration of humic acid and sodium alginate solution, respectively. Compared to the commercial NF270 membrane, the NF-TPEI membrane exhibited significantly improved separation performance in terms of permeance and fouling resistance, which provided more possibilities for high-performance LNF membranes toward the treatment of wastewater with organic contaminants.

Sulfamethoxazole (SMX) is a frequently detected antibiotic in groundwater, raising environmental concerns. Persulfate oxidation is used for micropollutant removal. To investigate SMX transformation by persulfate, experiments were conducted using heat-activated persulfate at pH 3, 7, and 10. TP269a (SMX-hydroxylamine) and TP178 were identified as the dominant TPs across the pH levels. The exclusive formation of 4-nitroso-SMX, 4-nitro-SMX, and TP518 at pH 3 highlighted the role of SO₄^•– in attacking the NH₂. At pH 7 and 10, 3A5MI emerged as the dominant TP. Carbon isotopic fractionation (ε_C = −1.3 ± 0.5‰, −1.1 ± 0.4‰, and −1.1 ± 0.3‰ at pH 3, 7, and 10) remained consistent across pH levels, caused by the formation of TP178 involving C–S bond cleavage. An inverse nitrogen isotope fractionation at pH 3 (ε_N = +0.68 ± 0.11‰) was associated with SO₄^•–-induced single-electron transfer. Conversely, normal nitrogen isotope fractionation at pH 10 (ε_N = −0.27 ± 0.04‰) was associated with N–H bond cleavage by H abstraction through HO^• and N–S bond cleavage. The inverse nitrogen isotope fractionation at pH 7 indicated that the dominant pathway involved SO₄^•– reactions, accounting for 74%. Overall, the results highlight the potential of CSIA to elucidate SMX oxidation pathways.

Most models do not explicitly simulate droplet-resolved cloud chemistry and the interactions between turbulence and cloud chemistry due to large associated computational costs. Here, we incorporate the formation of isoprene epoxydiol secondary organic aerosol (IEPOX-SOA) in individual droplets within a one-dimensional explicit mixing parcel model (EMPM-Chem). We apply EMPM-Chem to simulate turbulence and droplet-resolved IEPOX-SOA formation using a laboratory cloud chamber configuration. We find that the dissolution of IEPOX gases is weighted more toward larger cloud droplets due to their large liquid water content (compared to smaller droplets), while the conversion of dissolved IEPOX to IEPOX-SOA is much greater within smaller deliquesced haze particles due to their higher acidity and ionic strengths compared to cloud droplets. We also apply the EMPM-Chem model to simulate how IEPOX-SOA formation evolves in individual cloud droplets within rising cloudy parcels in the atmosphere. We find that as subsaturated air is entrained into and turbulently mixed with the cloud parcel, evaporation causes a reduction in droplet sizes, which leads to corresponding increases in per droplet ionic strength and acidity. Increased droplet acidity, in turn, greatly accelerates the kinetics of IEPOX-SOA formation. Our results provide key insights into single cloud-droplet chemistry, suggesting that entrainment mixing may be an important process that increases SOA formation in the real atmosphere.

Large-scale oceanic assessments are key for determining the persistence and long-range transport potential of organic pollutants, but there is a dearth of these for organophosphate esters (OPEs), widely used as flame retardants and plasticizers. This work reports the latitudinal distribution (42°N–70°S) and vertical profiles (from the surface to 2000 m depth) of OPEs in the Atlantic and Southern Oceans and explores their biogeochemical controls. The latitudinal gradient shows higher surface OPE concentrations near the equator than at higher latitudes, consistent with the prevailing oceanic and atmospheric circulation, and measured wet deposition events. At the deep chlorophyll maximum depth, there was an inverse correlation between the concentrations of the OPEs and phytoplankton biomass, with the lowest concentrations in the Southern Ocean, consistent with the role of the biological pump depleting the levels of the OPEs from the photic zone. OPE latitudinal trends in the deep ocean (2000 m depth) resembled those at the surface with maximum intertropical concentrations. Analysis derived from OPE concentrations at the bottom of the photic zone and in the minimum oxygen layer suggested a complex dynamic biogeochemical cycling driven by transport, degradation, and redissolution of OPEs with depth. OPEs are persistent enough to reach all oceanic compartments, but a quantitative resolution of the sources, sinks, seasonality, and biogeochemical cycles will require future research.

With the upcoming transition to clean electric vehicles, the sources of volatile organic compounds (VOCs) in the ambient environment are rapidly changing and highly uncertain. Here, through systematic characterization of emissions from a typical apartment in a Chinese megacity (Shenzhen), we show that indoor environments contribute significantly to the levels of ambient (i.e., outdoor) VOCs. In particular, we observe that the majority of indoor VOCs originate from unoccupied spaces, demonstrating temperature-dependent release from indoor surface reservoirs. The total indoor-to-outdoor VOC emission rates varied from 53 to 2300 mg day^–1 (median 230 mg day^–1) during unoccupied periods, influenced by both the air exchange rate and indoor temperature. Reanalysis of literature data from various building studies worldwide corroborates our findings and reveals that indoor-to-outdoor emissions scale with room volume, with an average emission rate of 0.33 ± 0.03 mg h^–1 m^–3. Our study implies that indoor-to-outdoor emissions significantly contribute to urban VOC levels, rivaling traditional urban sources, e.g., power generation and biomass burning. This is particularly true for oxygenated VOCs, such as methanol, amounting to ∼60% of transportation emissions. The findings change our understanding of the role of indoor VOC contributions to outdoor air quality, whose importance will increase as controls on industrial and transportation emissions intensify.

Bisphenol analogues have been shown to have similar estrogenic activity to that of BPA and may affect fetal development. However, no human studies have examined the effects of perinatal exposure to emerging bisphenol alternatives [bisphenol G, bisphenol M, and bisphenol BP (BPBP)] on small for gestational age (SGA) and how placental function may mediate the relationship. Here, 13 urinary bisphenol analogues were detected in 1054 contemporary pregnant women, and BPA was still the most dominant congener. Logistic regressions identified BPA and its traditional alternatives [bisphenol B (BPB), bisphenol E (BPE), bisphenol Z, and bisphenol AP (BPAP)] as being associated with an elevated risk of SGA (all ORs > 1.80, P < 0.05). In contrast, the emerging substitutes, despite high occurrences, all showed much attenuated risk. Mixture effect models Bayesian kernel machine regression and quantile-based g-computation demonstrated that coexposure to bisphenols was strongly correlated with SGA risk (OR = 2.70, P < 0.001), with BPA and the conventional substitutes (BPB, BPE, and BPAP) as primary effect drivers, outweighing the effect from emerging substitutes. Finally, mediation analysis revealed that the placental function index estriol mediated the relationship between exposure and SGA, dominated by BPBP (25.4%). Our findings provide new epidemiological evidence that early BPA alternatives may pose a higher risk for offspring development than those emerging alternatives, potentially via mediation by compromised placental function. Future toxicity assessments and validation studies in other settings on these emerging bisphenols are needed.

Ammonia (NH₃) is the most prevalent alkaline gas in the atmosphere, with its elevated concentrations posing significant adverse impacts on air quality, ecosystems, and human health across diverse spatial and temporal scales. Given the ongoing global change and intensified anthropogenic NH₃ emissions, it is projected that the global surface NH₃ concentration will escalate further. Here, based on ground observations, gridded data of organic and inorganic nitrogen fertilizer applications, meteorological data, and ancillary information, we estimated changes in global monthly surface NH₃ concentration during 2001–2019 at a 0.1°× 0.1° resolution. A novel scale-adaptive approach, essentially an Ensemble Random Forest Model built upon Rotated Quadtree Partitioning and Box-Cox Transformation, was developed. The model well reproduced the spatial and temporal patterns of surface NH₃ observations, particularly capturing peak and valley values (R² = 0.91 and slope = 0.82 for the whole; R² = 0.79 and slope = 0.70 for testing). The results indicate a global increase in surface NH₃ concentration over 2001–2019, from 1.44 μg m^–3 yr^–1 in 2001 to 1.51 μg m^–3 yr^–1 in 2019. Notably, hotspots of elevated NH₃ concentrations were located in northern South Asia, northern China, the Sahel area, southeast South America, and central United States. Decreased SO₂ emissions and increased fertilizer applications dominated the increase of surface NH₃ concentrations in China, while in South Asia, the increase was primarily driven by organic and inorganic nitrogen inputs. Temperature changes were identified to play an important role in affecting surface NH₃ concentrations in most regions, particularly in Africa, South America, and Oceania. These findings have the potential to facilitate research on global nitrogen cycle and its environmental footprints and inform the development of locally or regionally tailored nitrogen management strategies. Furthermore, the proposed modeling algorithm showcases its capability in capturing intricate patterns and relationships within highly spatially heterogeneous data, thereby addressing up-scaling challenges associated with multimodal site observations.

Recent plastic flow research has largely focused on commodity plastics (PE, PP, PVC, PS, ABS), yet a sizable share of other polymer types remains understudied. These non-commodity plastics suffer from inconsistent definitions, complex classifications, and data gaps, which hinder accurate assessment of their production, use, and end-of-life management. This study develops dynamic material flow analysis to investigate 12 key “non-commodity” plastics in China─including PET, PU, seven engineering plastics, and three thermosetting plastics─and addresses these knowledge gaps. Our results show that in 2022, China produces approximately 85 million tonnes of these polymers, a volume comparable to commodity plastics, with 35% used in plastic products and the remainder in non-plastic applications (e.g., fibers, rubber). PET is predominantly employed in short-lifespan packaging, whereas PU, engineering plastics, and thermosetting plastics find use in longer-lifespan applications, underscoring the need for targeted recycling strategies─particularly chemical recycling for PU and thermoset products. Revisiting the scope of “plastics” using scientific criteria can help mitigate definitional ambiguities and guide more effective policymaking. By improving data availability and tracking this underexplored non-commodity category, our study lays the groundwork for more accurate assessments and interventions to reduce plastic pollution.

This cross-sectional study investigated associations between exposure to organophosphate flame retardants and plasticizers (PFRs) and reproductive and steroid hormones in peripubertal children from the Hokkaido Birth Cohort (429 children aged 9–12 years; between September 2017 and March 2020). Thirteen urinary PFR metabolites and 14 plasma steroid hormones were investigated using LC–MS/MS and four reproductive hormones were investigated using immunoassays. Linear regression for single PFR, quantile g-computation, and Bayesian machine kernel regression (BKMR) models for the PFR mixtures were used to examine the association between hormones and PFRs. Among boys, significant positive associations were observed between estradiol and ΣTCIPP and ΣTBOEP, and inverse associations were identified between insulin-like factor-3 (INSL3) and ΣTCIPP, and between luteinizing hormone (LH) and ΣEHDPHP. The PFR mixture was associated with the trends of increasing estradiol and androstenedione, and decreasing cortisol, cortisone, LH, inhibin B, and INSL3. Among girls, androstenedione and ΣTCIPP, testosterone and ΣEHDPHP, (androstenedione + testosterone)/DHEA-S and ΣTCIPP, and ΣEHDPHP and ΣTPHP were significantly correlated. The PFR mixture showed trends of increasing testosterone, androstenedione, and inhibin B, and decreasing cortisol, cortisone, and INSL3. Individual PFRs and PFR mixtures altered steroids and reproductive hormones in peripubertal children.

Chemotactic bacteria may overcome challenges posed by nonaqueous-phase liquid (NAPL) contaminants of low solubility in groundwater and limited bioavailability in tight pores by preferentially migrating to NAPL sources. We explored the transport of chemotactic bacteria to NAPL ganglia at varying pore water velocities in a dual-permeability microfluidic device and using computer-simulated solutions of transport equations. In our experiments, bacteria exhibited a chemotactic response toward NAPL ganglia at the junctures of low- and high-permeability regions (i.e., micropockets), and the extent of retention initially increased with velocity and then decreased at the highest velocity. A dimensional analysis revealed that maximum accumulations occurred at moderate values of the Péclet number Pec=vmdpχo ∼10 in our system. We also found that accumulation dynamics in micropockets can be represented by a logistic equation incorporating convection and chemotaxis time scales τf=Livf and τche=la2χo, respectively. By analyzing seven literature studies on chemotaxis, we identified an exposure time scale to chemicals τexp=dpvf that was useful for evaluating the chemotaxis efficiency. Our study provided unique insights into the effect of fluid flow on chemotaxis in porous media by demonstrating that increasing the fluid velocity to some extent can promote chemotaxis. The dimensionless parameters inform the design of efficient bioremediation strategies for contaminated porous media.

The escalating environmental concern over secondary microplastics (SMPs) stems from their physicochemical evolution from primary microplastics (PMPs), yet the contribution of varying physicochemical transformations to the ultimate environmental risks remains unknown. In this study, a photomechanical degradation process was employed to convert the primary sunscreen-derived microplastics (SDMPs) into secondary SDMPs. While mechanical degradation caused physical fragmentation, photodegradation induced both physical and chemical alterations, introducing surface oxidation, chemical bond scission, and cross-linking to the secondary SDMPs. Employing a combination of alkaline digestion and pyrolysis GC-MS techniques, it was observed that both physical fragmentation and photooxidation led to heightened intracellular sequestration of MPs. Although the bioaccumulated SDMPs could be indicated by the enlarged lysosomes and fragmented mitochondria, toxicity of secondary SDMPs at the cellular level was primarily driven by chemical transformations post-photodegradation. A nontargeted analysis employing high-resolution mass spectrometry identified 46 plastic-associated compounds in the leachate, with photodegradation-induced chemical transformations playing a crucial role in the dissociation of hydrophobic additives and oxidative conversion of leached compounds. The toxicity of the leachate was exacerbated by photodegradation, with mitochondrial fragmentation serving as the primary subcellular biomarker, indicative of leachate toxicity. This study elucidates the pivotal role of photodegradation in augmenting the cytotoxicity of secondary SDMPs, shedding light on the intricate interplay between physicochemical transformations and environmental risks.

Traditional per- and polyfluoroalkyl substances (PFASs) have been observed in the remote Southern Ocean. In contrast, current knowledge about emerging PFASs, such as perfluoroether carboxylic acids (PFECAs), and their transport mechanisms remains ambiguous. In this study, the occurrence and transport of both traditional and emerging PFASs in the surface seawater of the Southeast Indian Ocean and Antarctic marginal seas are comprehensively discussed by integrating hydrological data. Long-chain PFASs were restricted to the north of the thermohaline front in the Southeast Indian Ocean, suggesting a transport barrier effect and the input of terrestrial contamination from low-latitude regions. Conversely, unexpectedly high levels of short-chain perfluorobutanoic acid (PFBA) were limited to the south of the Antarctic Circumpolar Current, preventing further northward transport. PFBA showed significant positive correlations with two emerging PFECAs, perfluoro-2-methoxyacetic acid (PFMOAA) and fluoro(heptafluoropropoxy)acetic acid (3:2 H-PFECA), which were also widely detected in Antarctic marginal seas for the first time. This suggests their similar sources and environmental behavior, as they were probably formerly accumulated in Antarctic snow through atmospheric deposition and released into seawater during the summertime melting process.

Remote marine regions are characterized by a high degree of cloud cover that greatly impacts Earth’s radiative budget. It is highly relevant for climate projections to represent the ice formation in these clouds. Therefore, it is crucial to understand the sources of ice-nucleating particles (INPs) that enable primary ice formation. Here, we report polysaccharides produced by four different aquatic eukaryotic microorganisms (Thraustochytrium striatum, Tausonia pullulans, Naganishia diffluens, Penicillium chrysogenum) as responsible ice-nucleating macromolecules (INMs) in these samples originating from the marine biosphere. By deriving a classical nucleation theory-based parametrization of these polysaccharidic INMs and applying it to global model simulations, a comparison to currently available marine atmospheric INP observations demonstrates a 44% contribution of polysaccharides to the total INPs of marine origin within −15 to −20 °C. The results highlight the relevance of biological INMs as part of the INP population in remote marine regions.

Nontarget screening (NTS) with liquid chromatography high-resolution mass spectrometry (LC-HRMS) is commonly used to detect unknown organic micropollutants in the environment. One of the main challenges in NTS is the prioritization of relevant LC-HRMS features. A novel prioritization strategy based on structural alerts to select NTS features that correspond to potentially hazardous chemicals is presented here. This strategy leverages raw tandem mass spectra (MS²) and machine learning models to predict the probability that NTS features correspond to chemicals with structural alerts. The models were trained on fragments and neutral losses from the experimental MS² data. The feasibility of this approach is evaluated for two groups: aromatic amines and organophosphorus structural alerts. The neural network classification model for organophosphorus structural alerts achieved an Area Under the Curve of the Receiver Operating Characteristics (AUC-ROC) of 0.97 and a true positive rate of 0.65 on the test set. The random forest model for the classification of aromatic amines achieved an AUC-ROC value of 0.82 and a true positive rate of 0.58 on the test set. The models were successfully applied to prioritize LC-HRMS features in surface water samples, showcasing the high potential to develop and implement this approach further.

Acute exposure studies have reported that chemical speciation significantly affects the developmental toxicity of perfluoroalkyl acids (PFAAs). However, the mechanisms underlying the chronic toxicity of PFAAs as a function of chemical speciation remain unknown. With an aim to gain more insights into the PFAA structure–toxicity relationship, this study exposed adult zebrafish to the acids and salts of perfluorooctanoate (PFOA), perfluorobutanoate (PFBA), and perfluorobutanesulfonate (PFBS) at environmentally realistic concentrations for 5 months. In the F0 generation, PFAA acids induced hypothyroidism symptoms more potently than their salt counterparts. After parental exposure, a chemical speciation-dependent transfer behavior was noted, with a greater burden of PFAA acids in the offspring. Similarly, PFAA acids were associated with higher risks of transgenerational defects and thyroid dysfunction during offspring embryogenesis. PFAA acids bound to thyroid receptor beta (TRβ) more strongly than their salts. An antagonistic interaction of PFOA and PFBS with TR activity was observed in vitro via the reduction of TRβ accessibility to target genes. CUT&Tag sequencing revealed disturbances due to PFAAs on the genomic target profile of TRβ, indicating that PFOA and PFBS interfere with multiple thyroidal and nervous processes. In conclusion, current findings provided evidence regarding the critical effects of chemical speciation on PFAA toxicity, highlighting the need to perform discriminative risk assessment and chemical management.

Building stock modeling can be used to identify trajectories that do not exceed the remaining carbon budget and support science-based pathways. A systematic approach is used from the field of prospective life-cycle assessment, which is based on systems thinking, to develop scenarios for the Austrian building stock that consider life-cycle greenhouse gas emissions. The influential parameters of the model are identified; their interactions are classified; quantitative future assumptions are adopted; and five scenario narratives are created. A maximum emission reduction of 90% from 2023 to 2050 is revealed. In comparison, leaving current policies in place would lead to a trajectory that reduces emissions by only 66%. Three additional scenarios achieve emission reductions between 84 and 86% by 2050, which may be compatible with the 2 °C carbon budget using an equal-per-capita approach. These scenarios represent different societal choices based on ambitious sufficiency (e.g., behavioral change), technological measures (e.g., a change in the industry), or both, with less effort from all actors. To ensure that Austria contributes to staying within the remaining carbon budget, policy makers are urged to systematically and quickly incorporate sufficiency into their policies and enable the necessary investments in carbon dioxide removal technologies.

Aerosol deposition significantly impacts ocean ecosystems by providing bioavailable iron (Fe). Acid uptake during the transport of Fe-containing particles has been shown to cause Fe dissolution. However, carbonate in dust particles affects the Fe acidification process, influencing Fe dissolution. Here, we carried out atmospheric observations and modeling to show that Fe solubility substantially increased from locations near dust sources to downwind regions in aged dust particles with pH > 3, driven by proton-promoted dissolution. We found that Fe solubility remained low when Ca solubility was under 45 ± 5%, but increased with Ca solubility when it was above 45 ± 5%. Moreover, we found that Fe dissolved in aqueous Ca-nitrate coatings on Fe-containing dust particles. Our results suggest that the mixing state and buffering capacity of carbonate and Fe minerals should be represented in atmospheric biogeochemical models to more accurately simulate acid Fe dissolution processes.

In the United States, more than 2 Gt of coal combustion residuals (i.e., coal ash) are stored in hundreds of disposal units. Recent federal regulations mandate the closure or retrofitting of most coal ash impoundments, presenting significant challenges for waste management. These regulatory pressures also present opportunities to reuse coal ash. However, the quality and quantity of discarded coal ash across the U.S. are not well known, even though this information is crucial for spurring its reuse for conventional and new material applications. This study describes a predictive model for the major element composition of coal ash in reserve at disposal sites of major U.S. coal-fired power plants. This model was constructed from coal purchase records of 705 power stations from 1973 to 2022 and was trained on coal ash composition data, showing that coal ash elemental composition is strongly associated with the source of feedstock coal. The model showed regional shifts in the major element contents of ash produced by power plants in the last 50 years, particularly for calcium and iron (expressed as %CaO and %Fe₂O₃), as power stations changed their source of coal over this time frame. Our approach enables an estimation of chemical composition for ash stored in waste impoundments at individual power stations. Such information can help to delineate the regional market resource potential of supplementary cements for concrete and other material innovations that would utilize coal ash harvested from disposal sites across the U.S.

Silica scaling poses a substantial challenge in the advanced treatment of industrial wastewater by reverse osmosis (RO) membranes, while the existing methods modifying RO membranes to enhance antisilica scaling performance often compromise water permeance. Herein, we fabricated a sulfonated RO membrane (SLRO) using sodium lignosulfonate as a comonomer, achieving an enhanced charge density and reduced coordination capacity. SLRO exhibited superior antisilica scaling performance, reducing scaling rates by ∼145, ∼166, and ∼157% under acidic, neutral, and alkaline conditions compared to the control. Reduced density gradient analysis confirmed that sulfonic acid groups (−SO₃H) on the SLRO surface increased the repulsion of silicic acid. Moreover, the SLRO demonstrated reductions of ∼112, ∼137, and ∼133% in cation-mediated silica scaling rates under the same conditions, attributed to the weaker coordination between −SO₃H and cations, which diminished the cation-bridging effect. Furthermore, SLRO membranes exhibited high pure water permeance (3.3 L m^–2 h^–1 bar^–1) and NaCl rejection (99.2%), with a water/NaCl selectivity (7.8 bar^–1) three times greater than that of the control (2.6 bar^–1), primarily attributed to increased surface roughness and reduced apparent thickness of the PA layer. Our work provides a robust strategy for fabricating silica scaling-resistant RO membranes with improved perm-selectivity.

Honeybees (Apis mellifera) are important pollinators. Their foraging behaviors are essential to colony sustainability. Sublethal exposure to pesticides such as neonicotinoids can significantly disrupt these behaviors, in particular pollen foraging. We investigated the effects of sublethal doses of the neonicotinoid imidacloprid on honeybee foraging, at both individual and colony levels, by integrating field experiments with artificial intelligence (AI)-based monitoring technology and mechanistic simulations using the BEEHAVE model. Our results replicated previous findings, which showed that imidacloprid selectively reduces pollen foraging at the colony level, with minimal impact on nectar foraging. Individually marked exposed honeybees exhibited prolonged pollen foraging trips, reduced pollen foraging frequency, and instances of drifting pollen foraging trips, likely due to impaired cognitive functions and altered metabolism. These behavioral changes at the individual level corroborated the previous model predictions derived from BEEHAVE, which highlights the value of combining experimental and simulation approaches to disentangle underlying mechanisms through which sublethal effects on individual foragers scale up to impact colony dynamics. Our findings have implications for future pesticide risk assessment, as we provide a robust feeding study design for evaluating pesticide effects on honeybee colonies and foraging in real landscapes, which could improve the realism of higher-tier ecological risk assessment.

The catalytic deactivation caused by SO₂ impurity remains a great challenge in the efficient destruction of industrial chlorinated volatile organic compounds (CVOCs). Herein, a Ce–Mn@ZrO₂–SO₄^2– catalyst with a Ce–O–Mn active system and ZrO₂–SO₄^2– protective layer was rationally engineered, which exhibits superior activity for chlorobenzene (CB) and SO₂ cotreatment at 228 °C, achieving 90% CB mineralization─over 80% higher than that of the CeO₂ catalyst. In situ characterization and theoretical calculation results reveal that the SO₄^2– groups not only inhibit the adsorption of SO₂ molecules through steric hindrance and electrostatic repulsion but also act as the Brønsted acid sites (BAS) to promote C–Cl cleavage of chlorobenzene (CB) and accelerate the desorption of Cl radicals as inorganic chlorine (HCl and Cl₂). Additionally, the Ce–O–Mn structure accelerates electron transfer between active sites, enhances the strength of Lewis acid sites (LAS), and weakens the lattice oxygen stability to generate oxygen vacancies (O_v). These features collectively result in the excellent chlorine and sulfur resistance of the Ce–Mn@ZrO₂–SO₄^2– catalyst. Compared to CeO₂ and Ce–Mn@ZrO₂, chlorinated and sulfated byproducts respectively decrease by 7.9 and 2.7 times in the presence of 100 ppm SO₂. This study provides a feasible and promising strategy for engineering efficacious non-noble metal catalysts toward CVOCs’ deep purification with SO₂ impurity, showcasing substantial economic and environmental benefits.

Water, as a finite and vital resource, necessitates water quality monitoring to ensure its sustainable use. A key aspect of this process is the accurate measurement of critical parameters such as chemical oxygen demand (COD). However, current spectroscopic methods struggle with accurately and consistently measuring COD in large-scale, complex water environments due to an insufficient understanding of water spectra and limited generalizability. To address these limitations, we introduce the physicochemical-informed spectral Transformer (PIST) model, combined with ultraviolet–visible-shortwave-near-infrared (UV–vis-SWNIR) spectroscopy for water quality sensing. To the best of our knowledge, this is the first approach to combine Transformer with spectroscopy for water quality sensing. PIST integrates a physicochemical-informed block to incorporate existing physical and chemical information into the spectral encoding for domain adaptation, along with a feature embedding block for comprehensive spectral features extraction. We validated PIST using an actual surface water spectral data set with extensive geographic coverage including the Yangtze River and Poyang Lake. PIST demonstrated notable performance in COD sensing within complex water environments, achieving an impressive R² value of 0.9008 and reducing root mean squared error (RMSE) by 45.20% and 29.38% compared to benchmark models such as support vector regression (SVR) and convolutional neural network (CNN). These results emphasize PIST’s accuracy and generalizability, marking a significant advancement in multidisciplinary approaches that combine spectroscopy with deep learning for rapid water quality sensing.

More than 13 years after the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, concerns remain about drinking water contamination from artificial radionuclides and the ongoing discharge of tritiated water into the Pacific Ocean. However, natural radionuclides unrelated to FDNPP releases can also contribute to human radiation exposure. Here, we measured radionuclides in Fukushima tap and groundwater to assess exposure from ²²²Rn (natural); ¹³⁷Cs (artificial); and ³H (both artificial and natural). Ten years after the accident, all drinking water samples had ¹³⁷Cs levels below detection limits (<0.02 Bq L^–1), while only groundwater had elevated ²²²Rn (<3–399 Bq L^–1). Trace amounts of ³H (0.07–0.55 Bq L^–1) were measured in both sources, with tap water generally exhibiting higher levels. ³H levels in drinking water did not increase after several discharges of tritiated water into the Pacific Ocean. Estimated annual effective doses from tap water were 0.57 μSv (¹³⁷Cs), 0.0058 μSv (³H), and 20 μSv (²²²Rn). For groundwater, doses were 0.57 μSv (¹³⁷Cs), 0.0072 μSv (³H), and 1020 μSv (²²²Rn). The primary radiation exposure source is naturally occurring ²²²Rn from rock formations. Boiling well water in a vented area reduced radon levels by 95%, significantly mitigating exposure.

Atmospheric black carbon (BC) particles play an important role in air pollution, climate change, and human health. Evaluating BC’s impacts by model simulation requires an understanding of the distribution of other aerosol species between those containing BC and those free of BC particles during the atmospheric aging process. Previous studies observed a large variability in the mass fraction of BC-containing particles in PM_2.5 (F_{BC-containing}), complicating the determination of their impacts. In this work, we conducted field observations in various polluted environments across China for process-level understanding of F_{BC-containing}. We find that the variability in F_{BC-containing}, ranging from 10 to 90%, can be elucidated by the concept of atmospheric oxidation capacity (AOC). The contrast between observations of F_{BC-containing} during haze events is determined by whether the initial aging of freshly emitted BC is limited by daytime AOC levels. We quantify and parametrize F_{BC-containing} by resolving BC aging under different AOC conditions, indicating efficient formation of secondary aerosol on BC-containing particles when daytime-average concentrations of O_x (i.e., O₃ + NO₂) exceed 80 μg m^–3. Our study provides valuable insights into BC mixing state representations under different environments, facilitating accurate evaluation of BC’s impacts in atmospheric models.

This study investigates the role of hydrogen as a decarbonization strategy for the iron and steel industry in the United States (U.S.) in the presence of an economy-wide net zero CO₂ emissions target. Our analysis shows that hydrogen-based direct reduced iron (H₂DRI) provides a cost-effective decarbonization strategy only under a relatively narrow set of conditions. Using today’s best estimates of the capital and variable costs of alternative decarbonized iron and steelmaking technologies in a U.S. economy-wide simulation framework, we find that carbon capture technologies can achieve comparable decarbonization levels by 2050 and greater cumulative emissions reductions from iron and steel production at a lower cost. Simulations suggest hydrogen contributes to economy-wide decarbonization, but H₂DRI is not the preferred use case for hydrogen in most scenarios. The average abatement cost for U.S. iron and steel production could be as low as $70/tonne CO₂ with existing technologies plus carbon capture, while the cost with H₂DRI rises to over $500/tonne CO₂. We also find that IRA tax credits are insufficient to spur hydrogen use in steelmaking in our model and that a green steel production tax credit would need to be as high as $300/tonne steel to lead to sustained H₂DRI use.

Superfund sites are where soil, air, and water are polluted with hazardous materials. Individuals residing and working in these areas are often exposed to metals and other hazardous materials, leading to many adverse health outcomes, including cancer. While individuals are often exposed to multiple chemicals simultaneously, the combined effect of such exposures remains largely unexplored. Here, we investigated the toxicity of metal mixtures in five categories of in vitro assays measuring cytotoxicity, oxidative stress, genotoxicity, cytokine release, and angiogenesis. After testing these mixtures in primary cells and cell lines, we discovered that the nickel/arsenic/cadmium and beryllium/arsenic/cadmium combinations exhibited higher cytotoxicity than their individual compounds, suggesting that the mixtures amplified the cytotoxic effect. To investigate the mechanism underlying their toxicity, we evaluated metal-induced oxidative stress, as oxidative stress is a common factor in most metal-related toxicities. Our results showed that cadmium-induced oxidative stress was increased in mixtures. Some mixtures that induced oxidative stress further increased DNA damage, inhibited DNA synthesis, and activated p53. In addition, some mixtures significantly increased interleukin-8 secretion and angiogenesis more than their component compounds. Our findings offer important insights into metal-related toxicity at Superfund sites.

Enriching oxygen species in perovskite catalysts provides more active sites for the catalytic oxidation of air pollutants, but its further application in environmental chemical engineering is still constrained by the inherent lack of oxygen species reactivity and the difficulty of replenishing depleted oxygen species. Herein, we present a scalable one-pot strategy for the in situ fabrication of a homogeneously distributed heterostructure, which brings La₂CuO₄ perovskite a 58-fold activity enhancement and robust antisintering/water/coke in toluene oxidation, higher than currently reported perovskite catalysts. Superior to the single “oxygen enrichment” effect of conventional surface-aggregated heterostructures, the homogeneously distributed heterostructures induce the reactivity enhancement of adsorbed oxygen and the backfilling/replenishment of depleted lattice oxygen, which break through the rate-determining steps of the low-temperature Langmuir–Hinshelwood and the high-temperature Mars–van Krevelen mechanisms, respectively. The scalability has been demonstrated in broader perovskite systems and for oxygen evolution reaction, offering a more dependable oxygen supply for environmental catalysis.

The temperature for complete disintegration of spent lithium-ion battery (LIB) cathode materials is typically in a range of 750–1400 °C, resulting in intensive energy consumption and high carbon emissions. Here, we promote the bond activation of oxygen in LiNi_0.5Co_0.2Mn_0.3O₂ and carbon in graphite electrodes, achieving rapid gasification and thermal decomposition of active crystals at lower temperatures in the absence of other activating agents. The activation of C and O bond leads to the storage of internal energy and the transition of the crystalline phase (single crystal to polycrystal) of the active crystals. Density functional theory modeling confirms that the CO adsorption energy is significantly higher with C_a–O_a (−3.35 eV, C and O activation) than with no activation (−1.66 eV). The differential charge results show that the bond activation model has the highest charge accumulation and consumption, improving the electron transfer. The Bader charge transfer between C_a–O_a and CO is also the largest, with a value of 0.433 |e|. Therefore, synchronous activation of C and O bonds can reduce the decomposition temperature of active crystals by 200 °C and allows a low-temperature pyrolysis recycling of retired LIB cathode materials. Our research provides a potential strategy for low-carbon recycling of retired LIBs worldwide.

Selenium (Se) contamination is widespread, and Se(VI) removal from water is particularly challenging. This study evaluated Se(VI) removal using iron electrocoagulation (EC) in a flow-through reactor under various water chemistry and operating conditions. Effective Se(VI) removal (>98% from 1000 μg/L Se) was achieved under anoxic conditions with an iron dose as low as 30 mg/L and an EC reactor residence time as short as 11 s that was followed by a 1-h settling period. The removal remained stable over an extended operating time (24 h) and involved the generation of reactive Fe(II)/Fe(III) solids (green rust and magnetite). Oxic conditions were less effective for Se removal because of limited Se adsorption at the elevated pH of the effluent. The immobilized Se in the solids was in a reduced form (-II or 0), but about 70% of Se was oxidized after air exposure. Despite the reduced forms of Se being oxidized, very little Se was released from the solids and the toxicity characteristic leaching procedure indicated that EC-generated solids can be classified as nonhazardous. This study highlights the potential of flow-through iron EC to produce iron-containing adsorbents and reductants that can be tailored for Se(VI) and other oxyanion removal. It also offers practical insights into designing effective treatment systems and ensuring the safe disposal of EC-generated residual solids in real-world applications.

Nitrogen fertilizer application is accompanied by intense release of multiple reactive nitrogen (Nr) gases such as nitrous acid (HONO), ammonia (NH₃), and nitric oxide (NO) from the soil, influencing atmospheric chemistry and air pollution. In current emission inventories, postfertilization soil emissions are poorly characterized due to inaccurate identification of fertilization timing and location. Moreover, pre-existing studies predominantly focus on individual Nr gases, and a comprehensive understanding of simultaneously emitted Nr gases from fertilization and their impacts on air quality is still limited. Here, we developed a novel method to identify the dryland fertilization activity based on satellite and reanalysis data sets. Then, we updated a dynamic soil Nr emissions model (WRF-SoilN-Chem) with lab-derived parametrization and applied it to analyze the time- and space-varying Nr emissions and their effects on air quality. It is estimated that the Nr emissions from a typical fertilization event in the Yangtze River Delta (YRD) region increased ozone (O₃) and nitrate concentrations by 2.5 and 18.2%, respectively. HONO and NH₃ emissions jointly enhanced nitrate production via gas–particle partitioning. An accurate representation of fertilization and meteorology–emission–chemistry coupled modeling would greatly improve the understanding of the soil Nr emissions and their impacts on regional air pollution.

Atmospheric ammonia (NH₃) has multiple impacts on the environment, climate change, and human health. China is the largest emitter of NH₃ globally, with the dynamic inventory of NH₃ emissions remaining uncertain. Here, we use the second national agricultural pollution source censuses, integrated satellite data, ¹⁵N isotope source apportionment, and multiple models to better understand those key features of NH₃ emissions and its environmental impacts in China. Our results show that the total NH₃ emissions were estimated to be 11.2 ± 1.1 million tonnes in 2020, with three emission peaks in April, June, and October, primarily driven by agricultural sources, which contributed 74% of the total emissions. Furthermore, employing a series of quantitative analyses, we estimated the contribution of NH₃ emissions to ecosystem impacts. The NH₃ emissions have contributed approximately 22% to secondary PM_2.5 formation and a 16.6% increase in nitrogen loading of surface waters, while ammonium deposition led to a decrease in soil pH by 0.0032 units and an increase in the terrestrial carbon sink by 44.6 million tonnes in 2020. Reducing agricultural NH₃ emissions in China would contribute to the mitigation of air and water pollution challenges, saving damage costs estimated at around 22 billion US dollars due to avoided human and ecosystem health impacts.

Detritusphere is a hotspot of carbon cycling in terrestrial ecosystems, yet the mineralization of soil organic carbon (SOC) within this microregion associated with reactive oxygen species (ROS) remains unclear. Herein, we investigated ROS production and distribution in the detritusphere of six representative soils and evaluated their contributions to SOC mineralization. We found that ROS production was significantly correlated with several soil chemical and biological factors, including pH, water-soluble phenols, water-extractable organic carbon, phenol oxidase activity, surface-bound or complexed Fe(II) and Fe(II) in low-crystalline minerals, highly crystalline Fe(II)-bearing minerals, and SOC. These factors collectively contributed to 99.6% of the variation in ROS production, as revealed by redundancy analyses. Among ROS, hydroxyl radicals (^•OH) were key contributors to SOC mineralization, responsible for 10.4%–38.7% of CO₂ emissions in ROS quenching experiments. Inhibiting ^•OH production decreased C-degrading enzyme activities, indicating that ^•OH stimulates CO₂ emissions by increasing enzyme activity. Structural equation modeling further demonstrated that ^•OH promotes C-degrading enzyme activities by degrading water-soluble phenols to unlock the “enzyme latch” and by increasing SOC availability to upregulate C-degrading gene expression. These pathways contributed equally to SOC mineralization and exceeded its direct effect. These findings provide detailed insight into the mechanistic pathways of ^•OH-mediated carbon dynamics within the detritusphere.

Nonradical Fenton-like catalysis offers an opportunity to degrade extracellular antibiotic resistance genes (eARGs). However, high-loading single-atom catalysts (SACs) with controllable configurations are urgently required to selectively generate high-yield nonradicals. Herein, we constructed high-loading Fe SACs (5.4–34.2 wt %) with uniform Fe–N₄ sites via an optimized coordination balance of supermolecular assembly for peroxymonosulfate activation. The selectivity of singlet oxygen (¹O₂) generation and its contribution to eARGs degradation were both >98%. This targeting strategy of oxidizing guanines with low ionization potentials by ¹O₂ allowed 7 log eARGs degradation within 10 min and eliminated their transformation within 2 min, outperforming most reported advanced oxidation processes. Relevant interactions between ¹O₂ and guanines were revealed at a single-molecule resolution. The high-loading Fe SACs exhibited excellent universality and stability for different eARGs and water matrices. These findings provide a promising route for constructing high-loading SACs for efficient and selective Fenton-like water treatment.

Ultraviolet light-induced homolysis of hydrogen peroxide (UV/H₂O₂) can generate powerful hydroxyl radicals (^•OH) for sustainable water purification. However, the efficiency of the conventional bulk-phase UV/H₂O₂ system is limited by the low yield and utilization of ^•OH, in turn necessitating high UV energy input and long purification period. In this study, we present an innovative UV/H₂O₂ microdroplet system for enhanced pollutant degradation. The degradation of pollutants in sprayed microdroplets was accelerated by 8.5–63.3-fold compared to those in bulk water, demonstrating universal effectiveness across a range of pollutant types and diverse aqueous matrices. This enhancement stems from elevated ^•OH production at the air–water interface due to the enhanced UV absorbance of H₂O₂. The production of ^•OH in the microdroplet system was 45-fold higher than that in bulk water, facilitating rapid ^•OH-mediated pollutant degradation. Moreover, pollutants accumulate at the air–water interface, where ^•OH is concentrated, leading to higher utilization of ^•OH for mediating pollutant degradation before quenching. Our findings provide a solution to overcome the bottlenecks in ^•OH production and utilization, offering insights for improving the efficiency of UV/H₂O₂ water treatment systems.

Chlorine (Cl) radicals can profoundly affect the atmospheric oxidation capacity and the fates of pollutants. Hypochlorous acid (HOCl) is a potentially crucial Cl precursor, yet the understanding of its formation mechanisms and atmospheric impacts is still limited. Here, we observed high concentrations of HOCl in a coastal city of Southeast China during the autumn of 2022, with an average daytime peak of 181 ppt. Machine learning analysis identified Cl₂, O₃, nitrate, temperature, and iron as the primary factors affecting HOCl distribution. Beyond Cl₂ photolysis, both nitrate photolysis and aerosol iron photochemistry also contributed to Cl radical production, which drove daytime HOCl production through reactions involving ClO and HO₂ radicals in the presence of O₃. Both OH and Cl radicals released via HOCl photolysis increased the levels of RO_x radicals by ∼10%, thereby enhancing the daytime O₃ generation and atmospheric oxidation capacity. Our findings emphasize the significant role of HOCl in atmospheric chemistry and suggest that controlling O₃ levels could alleviate Cl radical production and its adverse impacts on air quality.

Geochemical multisurface models and their generic parameters for the solid-solution partitioning and speciation of metals have been used for decades. For soils the collective uncertainty and sensitivity of model parameters and soil-specific reactive surface properties has been insufficiently evaluated. We used statistical tools and data of diverse soils to quantify for Cd, Cu and Zn the uncertainty of model parameters and input values of the nonideal competitive adsorption (NICA)-Donnan model for organic matter (OM) coupled with the generalized two-layer model for metal-oxides. Subsequently, we quantified the uncertainty of speciation predictions and the sensitivity to model parameters and input values. Importantly, we established new generic NICA-Donnan parameters that substantially improved model accuracy, especially for Zn. Uncertainties generally followed Cu < Cd < Zn. With OM being the major binding surface across most soils, the affinity parameters (log K_i) were most influential. Compared to a “best-case” scenario with all relevant soil properties measured, a “simplified” scenario with assumptions about OM fractionation and metal-oxide specific surface area could be employed with a negligible effect on model accuracy and uncertainty. Our study provides a reference work with quantitative measures of model performance, which facilitates broader adoption of mechanistic multisurface models in addressing environmental challenges.

Artisanal and small-scale gold mining (ASGM) is one of the largest primary sources of mercury (Hg) pollution in the atmosphere globally; however, there is a paucity of atmospheric Hg data in ASGM areas. We measured atmospheric gaseous elemental mercury (GEM) concentrations and stable Hg isotopes at fine spatial resolution in the Madre de Dios region of Peru, where ASGM is a major source of Hg. This study employed new passive air samplers that overcome logistical challenges in measuring atmospheric Hg in remote locations. Regional GEM concentrations were elevated (∼1.3 to 11 ng m^–3) compared to the background (<1 ng m^–3), with very high GEM levels (∼10 to >5000 ng m^–3) associated with mining areas and gold shops. Because ASGM-derived GEM is isotopically distinct, its contribution to regional and local atmospheric Hg was estimated using an isotope mixing model and found to be generally over 70%. We also show that vegetation is taking up ASGM-derived GEM, affecting both the concentrations and isotope compositions of GEM as well as in foliage and litter samples. This supports vegetation uptake as a key removal process of GEM from the atmosphere and therefore a major source of Hg to terrestrial ecosystems and soils, which is heightened in ASGM regions.

The reduction of As(V) to As(III) has been proposed as an undesirable process, increasing the mobility and toxicity of arsenic. Although most studies revealed that As(V) reduction occurs in the aqueous phase, it remains unclear whether abiotic As(V) reduction driven by minerals in drought environments also exists. In this study, we examined the transformation of As(V) to As(III) mediated by ferrihydrite during drying processes using high-resolution X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectroscopy analyses. The results revealed that nearly 40.8% of ferrihydrite-sorbed As(V) was transformed to As(III) after placing the As(V)-adsorbed ferrihydrite solids in a drought-tolerant environment for 7 days. As(V) reduction occurred under both oxic and anoxic conditions, with the reduction rate being higher in an anoxic atmosphere than in oxygen and air. Chemical analysis revealed the presence of structural Fe(II) in ferrihydrite, which was attributed to the abundance of oxygen vacancy clusters, as evidenced by positron annihilation lifetime (PAL) analysis. Fe L-edge XANES analysis and DFT calculations demonstrated that structural Fe(II) in dried ferrihydrite played a vital role in As(V) reduction, inducing electron transfer from Fe to As atoms. The findings of this study highlight a potentially important but long-overlooked As(V) reduction pathway at mineral surfaces under drought conditions in dried soils.

Nondispersive infrared (NDIR) sensors offer high sensitivity, selectivity, and low operational costs, making them particularly well-suited for environmental gas monitoring, where accurate detection of gases such as CH₄ and CO₂ is essential. However, these sensors are highly sensitive to environmental conditions, including temperature and humidity, which can significantly affect detection accuracy. This study characterizes the effects of these conditions and applies machine learning models to correct signal biases caused by multiple environmental factors. Experiments simulating natural environmental conditions for CH₄ monitoring were conducted in the laboratory across a temperature range of 10–40 °C, relative humidity levels of 10–70%, and CO₂ concentrations ranging from 0 to 1000 ppm, revealing significant signal variability under these conditions. The simulations and their results were comprehensively validated at the Ito Natural Analogue Site (INAS), a real-world field-testing location dedicated to investigating environmental impacts. Using machine learning regression algorithms for comprehensive compensation of environmental influences, we successfully mitigated signal biases caused by environmental factors. This offers a cost-effective solution for improving detection accuracy and reliability while reducing system complexity and operational costs.

Frequent wildfires pose a serious threat to carbon (C) dynamics of forest ecosystems under a warming climate. Yet, how wildfires alter the temperature sensitivity (Q₁₀) of soil heterotrophic respiration (R_h) as a critical parameter determining the C efflux from burned landscapes remains unknown. We conducted a field survey and two confirmatory experiments in two fire-prone regions of China at <1, 3, 6, and 12 months after wildfires (n = 160 soil samples). We found that wildfire generally reduced the Q₁₀ for soil organic and mineral horizons within the first year after wildfire mainly due to substrate depletion, which was confirmed by a uniform inoculation experiment. Mineral protection of organic matter in the mineral horizon rich in iron/aluminum (hydr)oxides and a near-neutral pH in organic horizons of postfire soils further suppressed the Q₁₀. Decreased Q₁₀ persisted in organic horizons even after removing substrate limitation, reflecting the dominance of a thermally adapted, r-strategist microbial community in postfire soils. Moreover, fire-induced low C quality increased Q₁₀, which supported the C quality-temperature hypothesis, but a C-limited condition restricted this stimulatory effect. This study illustrates that a thermal compensatory response of R_h will help maintain C stocks in forest ecosystems after wildfires in a warming world.

Provincial inherent heterogeneity in resource endowment, steel demand, and managerial guidance poses not only challenges but also chances to the decarbonization of China’s iron and steel industry (ISI). Previous studies have primarily concentrated on the technological dimension at the national level or plant level but have neglected potential regional synergies. This study proposed a framework encompassing macroeconomic models and multi-objective algorithms to optimize interprovincial allocation of scrap resources for coordinating the steelmaking process transition, aiming to minimize total carbon emissions from ISI. Results indicate that optimizing scrap allocation can reduce carbon emissions by 173.97–215.66 million tons, achieving a 99% reduction by 2060 compared to 2020 levels. Under the coordination strategy, 19 out of 28 provinces can achieve carbon neutrality and realize more than 90% pollutant reduction in the ISI. Notably, provinces such as Hebei, Inner Mongolia, Shanxi, Heilongjiang, and Liaoning still need to import more scrap resources and implement innovative low-carbon technologies. Finally, we propose interprovincial coordinated transition strategies, including regional integration management, national data platform, and preferential economic instrument. This work guides national and provincial administrations to formulate differentiated low-carbon transition targets and collaborative actions in ISI, which can be also applied to other substantially heterogeneous industries to achieve carbon neutrality.

To explore the hypothesis that differential exposures to estrogen active chemicals may contribute to regional disparities in cancer incidence, a comprehensive targeted and nontargeted analysis was conducted over two seasons (2020) for drinking water samples from 120 households served by 8 public water systems (4 with historically elevated breast cancer incidence) and from 15 brands of retail water. All samples were analyzed using gas and liquid chromatography with high-resolution mass spectrometry and a bioassay for estrogen receptor agonism. Target compounds included disinfection byproducts, per- and polyfluoroalkyl substances (PFAS), trace elements, and compounds selected for their possible relation to breast cancer. Over 7500 GC and LC nontargeted molecular features passed all quality control filters in each sampling season and were prioritized for identification if they were related to measured estrogen receptor agonism or were present at higher levels in areas with high breast cancer incidence (n = 1036). Benzothiazole-2-sulfonic acid, acetyl tributyl citrate, and diphenyl sulfone were among the prioritized and confirmed nontarget compounds. Nine polycyclic aromatic hydrocarbons and two ketone derivatives displayed significant negative correlations with estrogen receptor agonism. Many prioritized compounds remained unidentified, as 84.4% of the LC features and 77.5% of the GC features could not be annotated with high confidence.