Abstract Bioassays have proven their use in water quality monitoring. This study presents a novel framework for deploying bioassays to enable compliance screening in relation to regulatory threshold values. Bioanalytical equivalent concentrations for chemicals are derived from bioactivity data to calculate for each bioassay response the Bioanalytical Risk Quotient percentage (BRQ%): the percentage of chemicals potentially surpassing their quality standard (QS). If the bioassay response indicates BRQ0, none of the individual chemicals with known bioactivity in the bioassay surpass their QS. Should the bioassay response indicate potential QS exceedance by some candidates, the magnitude of that exceedance is a guide to prioritize chemicals for confirmation by instrumental analyses. Multiple bioassays are required to cover compliance for all relevant chemicals. As a proof of concept, compliance with the Dutch Drinking Water Regulation was evaluated for 100 surface water monitoring events by derivation of BRQ% values for a battery of six bioassays. Full compliance could not be guaranteed for any of the water samples, with a median potential noncompliance for 13% of chemicals. The presented framework has potential for broader application, such as compliance testing related to QS for human health or the environment in a variety of matrices or for specific permits.
Abstract Urban sewer networks may be an underquantified source of environmental antibiotic resistance genes (ARGs), as ARG-bearing biomass, extracellular DNA, mobile genetic elements, and particle-associated material accumulate in wastewater, biofilms, and deposits before wet-weather release. Climate-driven intensification of heavy rainfall may enhance overflow, surcharging, flooding, and hydraulic connectivity between sewers and surface waters, increasing episodic ARG export. Here we synthesize current evidence using a coupled source–storage, mobilization–routing, and fate–exposure framework. Rainfall can detach biofilms, erode deposits, redistribute intracellular and extracellular ARGs between freely suspended and particle-associated states, and increase event loads even when concentrations decline through dilution. However, field studies rarely quantify antecedent stocks, release thresholds, hydrograph-resolved fluxes, source contributions, decay, or exposure dose. We therefore identify the state variables, rate functions, and measurements needed to couple sewer hydraulics, particle transport, microbial ecology, molecular surveillance, and exposure assessment. Reframing storm-associated antimicrobial resistance as a compartmental mass-balance and transport problem can move the field from occurrence mapping toward prediction of peak concentrations, event loads, deposition hotspots, persistence, and exposure likelihood in climate-stressed urban watersheds.
Abstract Per- and polyfluoroalkyl substances (PFAS) have been implicated in neurodevelopmental toxicity, yet direct evidence of their presence within the central nervous system (CNS) of children remains limited. We quantified 12 PFAS in cerebrospinal fluid (CSF) samples from 47 pediatric patients undergoing clinically indicated lumbar puncture in Nanjing, China. PFAS were detected in 100% of samples, with PFOA (detection frequency: 98%), PFHxS (96%), PFOS (89%), and 6:2 Cl-PFESA (68%) most prevalent; their CSF distribution patterns were generally consistent with those observed in pediatric serum samples from nearby regions. Median concentrations were numerically higher in children under 2 and under 6 years of age, but these differences were not statistically significant (p = 0.450 and p = 0.322; rank-biserial r = 0.110 and 0.145) and should be interpreted as nonsignificant in this small, clinically heterogeneous sample. The presence of PFAS in children’s CSF adds to the growing concerns about early-life neurotoxicant exposure. Importantly, this study involved a small cohort (n = 47) of critically ill children. Given the limited sample size, the underpowered age subgroups, and the potential influence of disease-related changes in barrier permeability, the measured concentrations should not be generalized to healthy children, and all age-related comparisons are exploratory.
Abstract Levoglucosan (LEV) has long been used as a tracer for biomass burning emissions due to its presumed atmospheric stability. However, recent studies suggest that its degradation rate varies significantly under different environmental conditions. This work investigates the heterogeneous oxidation of LEV by hydroxyl radicals (•OH) and the influence of initial particle acidity on its degradation. Experiments were conducted in a smog chamber using internally mixed LEV particles with either ammonium sulfate (AS) or ammonium bisulfate (ABS). The chemical composition of the particle was monitored using a high-resolution aerosol mass spectrometer (HR-AMS) during the experiment. The results show that low-initial pH particles accelerate LEV degradation by 7–8 times relative to high-initial pH particles, with mean second-order reaction rate constants of 4.46 × 10–11 and 6.03 × 10–12 cm3 molecule–1 s–1, respectively. Acidic conditions also favor the formation of highly oxygenated products, some of which likely fragment and evaporate into the gas phase. These findings imply that acidic particles significantly reduce LEV’s atmospheric lifetime (from 40 to 3 h) and its reliability as a biomass burning tracer, highlighting the need to incorporate acidity effects into atmospheric models.
Abstract Effective real-time control of wastewater treatment plants (WWTPs) remains challenging due to highly variable influent conditions, while regulation of external carbon sources (ECS) is critical for sustaining nitrogen removal and meeting increasingly stringent effluent standards. This study developed a systematic framework integrating online learning (OL) and reinforcement learning (RL) to optimize effluent quality and ECS dosing in a full-scale WWTP. Based on one year of high-frequency sensor data, Transformer (TF) was identified as the best-performing model among six machine learning methods, with a mean R2 of 0.91 across multiple effluent indicators. SHAP was employed to identify key features, which informed the design of a key-indicator-based time-decayed online learning (KTOL) strategy, enabling the Transformer model to maintain stable predictive performance under dynamic operating conditions. Building on this, RL enabled real-time ECS regulation. During a 10-day practical test, KTOL-TF-RL outperformed conventional feedback control by improving effluent compliance and reducing ECS usage by 21.8%. Monte Carlo simulations demonstrated robustness against sensor distortion and malfunction. Overall, the KTOL-TF-RL framework demonstrates the potential of intelligent control as a promising pathway for achieving cost-effective and resilient wastewater treatment.
We report on commensalism enabling the entire degradation of the sulfadiazine antibiotic by a consortium composed of Microbacterium sp. strain BR1 and Terrabacter. 13C,15N-labeled sulfadiazine was synthesized and used as sole source of carbon in axenic cultures of Microbacterium and Terrabacter as well as cocultures of both genera. HPLC analyses showed that Microbacterium degraded sulfadiazine with accumulation of 2-aminopyrimidine, while the Terrabacter culture did not degrade sulfadiazine. The consortium degraded labeled sulfadiazine without any accumulation of 2-aminopyrimidine. Cross-feeding was efficiently synchronized in the synthetic consortium, and the release of 2-aminopyrimidine from sulfadiazine by Microbacterium is a prerequisite for its degradation by Terrabacter. Raman spectra in the fingerprint region enabled the discrimination of the two genera at the single cell level and the calculation of the cell number ratio, providing quantitative insight into the population dynamics in coculture. The cell counts in axenic culture and coculture were consistent with HPLC analyses, reflecting their metabolic activities and trophic interactions. Stable isotope probing and subsequent analyses of Raman spectra of Terrabacter in the synthetic consortium revealed a significant shift from 1000 cm-1 to 988 cm-1, proving that this bacterium assimilates 2-AP for biomass synthesis and that less than 50% of Terrabacter cells were degrading 2-AP.
Abstract Biodiversity is central to the functioning, stability, and climate relevance of marine vegetated ecosystems, yet its role in macroalgal carbon sequestration remains underappreciated in current climate and biodiversity frameworks. Macroalgae contribute substantially to coastal primary production, habitat formation, and nutrient cycling, while supporting diverse ecological communities across temperate, tropical, and polar seas. However, their environmental value extends beyond that of carbon capture alone. In biologically diverse macroalgal systems, modulated biodiversity can also help control toxic materials arising from anthropogenic activities, including CO2, SOx, and NOx, by integrating these pollutants into existing elemental biogeochemical cycles and enabling their transformation into more benign and potentially useful chemical forms. In this review, we examine macroalgal biodiversity as a determinant of marine carbon sequestration potential across natural ecosystems, restoration efforts, and cultivated systems. We synthesize current understanding of how taxonomic and functional diversity influence carbon fixation, biomass stability, trophic transfer, detrital export, nutrient retention, pollutant buffering, and resistance to environmental stress. We further assess key uncertainties surrounding carbon permanence, ecological trade-offs, measurement, reporting, and verification, and the risks associated with simplified or monoculture-based deployment strategies. We argue that biodiversity should be treated not merely as a cobenefit of macroalgal systems but as a central design principle for evaluating their ecological performance, climate relevance, and broader capacity to restore biogeochemical balance in anthropogenically stressed environments.
Per- and polyfluoroalkyl substances (PFAS) are present in drinking water consumed by ~200 million United States (US) residents, but many are not detected by routine monitoring methods. Here, we aimed to better characterize the organofluorine mass budget in US drinking water samples from 19 sites in eastern Massachusetts. Extractable organofluorine (EOF) was detected at 16/17 sites served by community water systems (CWS) using conventional treatment techniques (coagulation, flocculation, clarification, and filtration). At these sites, a suite of 37 targeted PFAS accounted for 6-68% of the extractable organofluorine (EOF) and suspect screening identified fluorinated agrochemicals in almost all samples. High EOF concentrations in untreated source waters for two CWS that used granular activated carbon (GAC) and ion-exchange (IX) treatment, were reduced below detection in finished drinking water samples. Our EOF measurements were not selective for trifluoroacetic acid (TFA), so we measured concentrations in triplicate samples at one conventional treatment site, and from the IX, and GAC sites. At these sites, TFA concentrations were higher than EOF and were unaffected by treatment type. Results of this pilot study show GAC and IX treatment removed virtually all organofluorine in drinking water other than TFA.
Abstract A microbe-rich rhizosphere is a hotspot for emissions of nitrous oxide (N2O), a potent greenhouse gas. We hypothesized that residue carbon (C) inputs would alter the rhizosphere effect on N2O emissions due to different C limitations for microbes between rhizosphere and bulk soils. To test this hypothesis, we employed 15N tracing and molecular approaches in two tea-planted soils differing in nitrogen-related rhizospheric microbial abundance (RMA) at residue input rates of 0, 259, and 518 mgC kgsoil–1. We demonstrated that a negative rhizosphere effect on N2O emissions in low-RMA soil was significantly diminished under low C input but amplified under high C input. In contrast, a negative rhizosphere effect on N2O emissions in high-RMA soil was gradually diminished with increasing C input and shifted to be positive under high C input. In low-RMA soil, where denitrification almost dominated N2O production, the rhizosphere effect on nirS/nirK-type denitrifiers primarily regulated that on denitrification-derived N2O emissions. However, in high-RMA soil, where nitrification dominated N2O production, the rhizosphere effect on nitrogen mineralization mainly regulated that on nitrification-derived N2O emissions. Our results indicate that whether the rhizosphere effect on N2O emissions is positive or negative depends on the prevailing N2O production pathway under elevated C input.
Abstract Top-down quantification of fossil fuel-derived CO2 (CO2ff) using radiocarbon (14C) relies on the Suess effect, whereby 14C-free fossil emissions dilute atmospheric 14CO2. However, 14C releases from nuclear power plants (NPPs) increase the level of ambient 14CO2, offsetting fossil dilution and biasing CO2ff low. Pressurized water reactors (PWRs), dominant in China, emit most 14C as 14CH4, but the smaller 14CO2 fraction may still affect nearby air. We investigated the influence of PWR-derived 14CO2 from the Daya Bay and Lingao NPPs (Shenzhen, China) using grass samples collected in January 2025, representing 2024 growing-season carbon, together with a previously published 2022 vegetation Δ14C data set for comparison and joint spatial analysis. The results show detectable 14CO2 enrichment, with positive Δ14C values up to +3.2‰, confined to the northern near field (<5 km downwind). Outside this zone, Δ14C remained negative overall (−13.1‰ to −42.1‰), with no consistent 14CO2 enrichment at more distant sites or south of the NPPs. A first-order CO2ff-equivalent calculation indicates that this enrichment has an offsetting capacity of 8.3–8.8 ppm of CO2ff, exceeding the median apparent CO2ff signal at sites beyond ∼5 km. These findings demonstrate that PWR-derived 14CO2 can cause localized, directional interference in Δ14C-based CO2ff reconstructions and highlight the need to integrate nuclear 14C footprints into top-down CO2ff frameworks.
Abstract Carbon mineralization in ultramafic rocks offers durable CO2 storage, but whether CO2-rich fluids also promote hydrogen generation remains unresolved. Here we show, using paired CO2-bearing and CO2-free batch reactions combined with aqueous geochemistry, dissolved-gas measurements and X-ray microtomography, that both processes can proceed within the same water–rock system. CO2 lowered the fluid pH and accelerated silicate dissolution, increasing Mg2+, Ca2+, and dissolved silica. Yet, dissolved iron fell systematically under CO2 exposure, while molecular hydrogen rose and dissolved oxygen declined, indicating oxidation of Fe2+, transfer of electrons to water, and retention of oxidized iron in secondary solids. The rocks are initially low-porosity (<1%) and fracture-dominated, showing that this coupling develops even where the matrix pore space is limited. The combined fluid-chemistry, dissolved-gas, and redox data support iron oxidation as the chemical link between these co-occurring processes. These findings point to ultramafic formations as candidate subsurface reactors for simultaneous permanent carbon fixation and in situ generation of a clean energy carrier.
Abstract Interdisciplinary, international research collaborations are essential to expanding resilient global mineral supply chains sustainably and responsibly. We identify key research needs to achieve these objectives that address mining water consumption and contamination through tailing management and upstream process innovations. We also explore means of reducing solid waste from mines by repurposing it as a construction material and recovering minerals from aqueous waste streams. Introducing new technologies that improve water efficiency and reduce waste generation will bring trade-offs, including potentially increasing energy consumption. Accordingly, systems analysis is an essential tool for exploring these trade-offs and identifying innovations that can minimize them. These technologies will potentially influence how communities adjacent to mines experience social and environmental effects. Developing and implementing sensor networks to support community-based monitoring of the changes that adoption of these technologies will bring can support community-mine dialogue. Finally, energy system models can explore the potential regional or global effects of these changes on overall mining sector environmental effects. Innovation in the mining sector therefore requires collaboration among engineers, scientists, social scientists, policy experts, and others across academia, industry, governments, and nongovernmental organizations. Developing a secure, resilient, mineral supply chain that maintains or restores environmental quality while meeting global mineral demand requires supporting and sustaining interdisciplinary collaborations among nations.
Abstract Reliable quantification of neutral per- and polyfluoroalkyl substances (nPFAS) via headspace analysis remains hindered by unrecognized analytical biases. We reveal a severe, previously unquantified artifact arising from sorptive interaction between nPFAS and commonly used polytetrafluoroethylene (PTFE)/silicone septa, resulting in time-dependent signal loss exceeding 90% within 12 h. Incorporating septum sorption into the headspace equilibrium model shows that this artifact systematically distorts air–water partition coefficients (Kaw), artificially masking true nPFAS volatility and compromising environmental fate modeling. A simple aluminum-foil barrier successfully eliminates septum artifacts, restoring analyte stability and enabling reliable Kaw determination. These findings reveal a critical but underappreciated source of systematic error in headspace workflows, highlighting the need to account for sorptive artifacts to understand nPFAS environmental behavior.
Abstract Sulfuric acid-dimethylamine (SA-DMA) cluster formation drives new particle formation in polluted atmospheres, but growth mechanisms for large-size SA-DMA clusters (>8 molecules) remain unclear. In this study, we systematically investigated neutral SA-DMA and SA-DMA-ammonia (AM) clusters up to 10 molecules and found that the dominant stability-regulating mechanism shifted from acid–base interactions in small-size clusters to synergistic structural and acid–base effects in large-size ones, with growing stabilization by van der Waals forces. AM lowered the critical size of encapsulated configurations and significantly increased nucleation rate for clusters with ≥4 acid–base pairs. At larger sizes, the thermodynamic stability gap between binary and ternary clusters narrowed, with kinetic concentration effect dominating further growth. This work filled the critical gap in large-size cluster evolution research and provided theoretical support for multiprecursor synergistic nucleation.
Decentralized technologies, such as advanced oxidation processes (AOPs), offer an opportunity to destroy organic groundwater pollutants at their point-of-use but often require the addition of expensive catalyst materials and chemical reagents. Overlooked as a common nuisance in groundwater systems, natural iron has the potential to be used as an autochthonous catalyst in the abatement of organic contaminants via Fenton oxidation, a well-known AOP. However, its usefulness is hindered by the circumneutral pH of groundwater, which leads to its precipitation upon reacting once with ROS-generating oxidants such as hydrogen peroxide. As a solution to this issue, we developed a novel electrochemical flow-through system which enhances oxidation of organic pollutants via anodic redissolution of Fe3+ and cathodic regeneration of Fe2+. The electrochemically enhanced Fenton system displays excellent capacity for treating high concentrations of various pollutants in a single pass, using high, but environmentally relevant, levels of ferrous iron as the sole source of catalyst. Moreover, the modular, decentralized cell design and use of cheap graphite felt electrodes enables practical and energy efficient degradation of contaminants, well-suited for point-of-use applications. If paired with electrochemical hydrogen peroxide generation from oxygen in air, this technology presents an opportunity for "reagent-free" treatment of iron-rich, contaminated groundwater.
