Science of The Total Environment

Background Following the end of a public health emergency of international concern, divergence emerged between reported coronavirus disease 2019 (COVID-19) cases and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA concentrations in wastewater. Exploring viral, clinical, patient, and surveillance-related factors underlying this divergence, we developed models to predict clinically confirmed infections, hospitalizations, and severe cases. Methods In this observational study, we analyzed ~2 years of data from January 2022 in Kanagawa Prefecture, Japan, assessing associations between wastewater SARS-CoV-2 RNA concentrations and confirmed, hospitalized, and severe cases, adjusting for wave and variant effects. Findings Our models based on wastewater viral RNA concentrations showed high predictive accuracy (R^2 = 0.8199-0.9961), closely tracking confirmed, hospitalized, and severe cases. Models derived from earlier waves were applied to subsequent waves with residual correction based on prior prediction errors and maintained good predictive performance (root mean square error = 0.0665-0.2065). Divergence between wastewater viral RNA concentrations and reported cases was not explained by changes in viral shedding. Declines in patients' healthcare-seeking behavior and testing were associated with trends in confirmed cases, whereas milder clinical presentation was associated with severe case trends. The lineages XBB.1.9.2 and BA.2.86 were identified as candidates associated with reduced virulence. Interpretation By incorporating understanding of viral, clinical, and surveillance-related mechanisms, wastewater surveillance may enable prediction of case trends approximately one week earlier than official reporting and inform healthcare capacity planning.

Hepatitis E virus (HEV) is considered a predominantly foodborne pathogen in developed settings. During COVID-19 lockdown periods, however, HEV concentrations in wastewater at a treatment plant in Munich, Germany decreased, suggesting that pandemic-related behaviour changes inadvertently influenced transmission. In contrast, reported cases and wastewater data from a smaller catchment showed no comparable decline. To assess whether the observed reduction is compatible with a near-exclusively foodborne infection and to reconcile the contrasting signals across surveillance modalities, we developed a stochastic, individual-level model of HEV transmission, shedding, and ascertainment in Munich. Using Approximate Bayesian Computation, we calibrated this model to wastewater and case data from 2020-2023, first separately and then jointly. Posterior parameter estimates indicated a substantial decline in transmission during lockdowns to about 35-40% of the non-lockdown level, with the 95% credible interval entirely below 1 (no change). Joint inference suggested that possible modest lockdown-associated increases in diagnosis probabilities and higher measurement variability in the smaller catchment masked this effect in clinical and small-scale wastewater data, respectively. These findings demonstrate how wastewater-based surveillance, used alongside reported cases, can enable more robust parameter inference for models of under-reported pathogens like HEV, thereby supporting informed public health risk assessments.

The East Asian region, known for its high levels of human and fishery activities, experiences serious plastic pollution in the marine environment, especially in seawater and along coastlines. Wharf roaches (Ligia spp.) collected from the coast of western Japan frequently ingest expanded polystyrene (EPS), which is then excreted as microplastic through their feces. However, the impact of EPS exposure and ingestion on the gut microbiome of wharf roaches remains unclear. Thus, this study aimed to investigate the effects of EPS ingestion on the gut microbiota of wharf roaches by examining their gut microbiota and gene expression. The expression levels of more than 400 genes, including those associated with xenobiotic metabolism, and the abundance of gut microbial community were altered. Microbial analysis revealed that at least five archaeal types, two to four bacterial types, three to seven eukaryotic types, and three viral types were involved in a correlation network composed of strong associations. Among them, Haloquadratum, Halalkalicoccus, and Methanospirillum (archaea); Volvox (eukaryote); and Varicellovirus and T4-like viruses showed significantly increased abundance. Furthermore, covariance structure analysis indicated that the viruses and methanogens played key causal roles as characteristic factors related to EPS administration. In conclusion, EPS disrupts the intestinal environment of wharf roaches and serves as a potential material for viral activation and methane production. Building on our previous field study that identified wharf roaches as potential indicators of coastal EPS pollution, this study provides novel insights into the ecological impacts of EPS ingestion and consequences of plastic pollution.

Wastewater surveillance (WWS) is established as a vital tool for monitoring polio and SARS-CoV-2 with potential to improve surveillance for many other infectious diseases. This study evaluated the feasibility of detecting measles virus (MeV) RNA in wastewater as part of a national WS preparedness trial in Brisbane, Australia, from March to June 2025. Composite and passive sampling methods were employed in parallel at three wastewater treatment plants serving populations between 230,000 and 584,000. Nucleic acids were extracted and analyzed using RT-qPCR targeting MeV N and M genes to distinguish wild-type and vaccine strains. MeV RNA were detected in both 24-hour composite and passive samples on May 26 to 27, 2025 from the largest catchment of 584,000 which also included an international airport. No measles cases were reported in this city or region within 4 weeks of the WS detections. These were confirmed as vaccine-derived measles virus (MeVV) strain via specific RT-qPCR assay. Extraction recoveries varied (11.5% to 70.5%), with passive sampling showing higher efficiency. This is the first report of use of passive samples for detection of MeV. These findings are consistent with other studies reporting WWS results of both MeVV genotype A and wild type genotype B and/or D. It demonstrates the potential for sensitive MeV WWS with rapid differentiation of MeVV from wild type MeV shedding, including in airport transport hubs and with different sample types. Use of WWS could strengthen measles surveillance by enabling rapid detection of MeV RNA and supporting outbreak preparedness and response. This requires optimised methods which are specific to or differentiate wild-type MeV from MeVV. Furthermore, the successful detection of MeV using passive sampling in this study highlights its potential for deployment in diverse global contexts which may include non-sewered settings.

Microplastics are increasingly recognized as emerging contaminants in terrestrial ecosystems, yet their mechanistic impacts on soil multifunctionality remain poorly understood. Here, we evaluated the influence of two microplastic polymers, polyethylene terephthalate and polypropylene, on soil functioning by subjecting soils to a gradient of concentrations of these microplastics, and measuring six variables representing soil physical, chemical, and biological functions. A statistical framework combining multi-model inference with threshold detection and machine learning was implemented in this study to identify the main pathways of soil multifunctional change. Most significant responses followed nonlinear trends and threshold shifts, primarily in physical properties, indicating that microplastic stress first impacts soil structure before cascading to chemical and biological processes. We identified two system-level thresholds at 0.3% PP and 0.55% PET w/w; while random forest highlighted water-stable aggregates as the dominant predictor of overall soil multifunctionality. Our findings provide new quantitative evidence of complex soil multifunctionality responses to microplastic pollution. Most importantly, physical deterioration emerged as an early-warning signal of microplastic disturbance, thereby advancing our understanding of microplastic pollution on soil systems.

The increasing discharge of treated wastewater effluent poses a growing threat to freshwater ecosystems. Although wastewater treatment plants reduce chemical pollution, they do not fully remove many biologically active compounds. Behavioural responses in aquatic organisms provide sensitive and ecologically relevant indicators of sublethal contaminant exposure, offering insight into underlying physiological disruption and potential ecological consequences. Here, we examined the behavioural and neurotoxic effects of a seven-day experimental exposure to treated wastewater effluent in the noble crayfish (Astacus astacus). We quantified four ecologically important behaviours: (1) shelter use, a key antipredator strategy, (2) food seeking, (3) the ability to detect and respond to wastewater-associated olfactory cues, and (4) locomotor activity was assessed across all behavioural contexts. Cholinesterase (ChE) activity was measured as a biomarker of neurotoxicity. Exposure to wastewater effluent significantly altered crayfish behaviour. Exposed individuals exhibited higher locomotor activity compared to controls, exposed crayfish avoided areas containing wastewater cues, spending less time near the effluent source. Similarly, ChE activity was significantly reduced in exposed crayfish, indicating neurotoxic effects. The concurrence of ChE inhibition and behavioural modification suggests that effluent-derived contaminants may interfere with neural signalling pathways underlying crayfish locomotion and habitat selection. Overall, our results demonstrate that short-term exposure to treated wastewater effluent can induce both neurochemical disruption and ecologically relevant behavioural changes in A. astacus. Such alterations may increase vulnerability to predation and influence population dynamics in effluent-receiving waters, highlighting the importance of integrating behavioural endpoints with mechanistic biomarkers in assessing sublethal impacts of wastewater contamination.

Since 1995, European fisheries of Pecten maximus have faced the presence of Pseudo-nitzschia species, which are able to produce the neurotoxin domoic acid responsible for Amnesic Shellfish Poisoning (ASP). As filter-feeders, scallops can accumulate and retain domoic acid much longer than most other bivalves, from months to years. When concentrations exceed the regulatory threshold, fisheries are closed leading to economic concern. Inter-individual variability increases the difficulty to predict the depuration dynamics. Quantifying the correlations between domoic acid depuration in P. maximus and individual physiological traits, particularly body size, could improve the understanding of contamination and depuration. We analysed toxin dynamics in organs and assessed the effects of body size and growth. This analysis was based on two datasets from an experimental and an in situ depuration monitoring of P. maximus exposed to a natural bloom of toxic P. australis. Results showed that the distribution of domoic acid shifted among organs between contamination and two months of depuration. Toxin concentrations correlated negatively with body size during contamination and after two months of depuration, but shifted to a positive correlation after 7 months of depuration. This suggested that smaller scallops both accumulate more domoic acid and depurate it more rapidly. Dilution by growth appeared to explain the inversion of the correlation between domoic acid and body size throughout depuration. These results yield useful information for modelling these mechanisms, thus providing valuable tools for scallop fishery management facing ASP. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=60 SRC="FIGDIR/small/708139v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@1fd317org.highwire.dtl.DTLVardef@15b9032org.highwire.dtl.DTLVardef@57dae8org.highwire.dtl.DTLVardef@1e4c7fc_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIExperimental and in situ datasets allowed to quantify DA proportion dynamics in organs in P. maximus C_LIO_LIDA concentration and body size are negatively correlated during contamination phase, but positively after a 7-month depuration C_LIO_LIConsidering dilution by growth is important for young scallops to assess DA depuration dynamics C_LIO_LIBoth depuration rate and dilution by growth need to be considered to model DA depuration over the whole scallop size range C_LI

Per- and polyfluoroalkyl substances (PFAS) are globally recognised as emerging contaminants of concern due to their persistence, toxicity, endocrine-disrupting and immunosuppressive effects. Because of their extensive industrial use, PFAS are now widespread across ecosystems and accumulate in marine environments. Despite their ubiquity, the extent and drivers of PFAS contamination remain poorly characterised, particularly in marine systems. Odontocetes (toothed whales) are effective bioindicators of marine pollution, integrating contamination across regions, time, and trophic levels. Here, we present the first global assessment of factors influencing PFAS contamination in marine ecosystems by analysing standardised PFAS concentrations of PFNA, PFDA, PFUnDA, PFDoDA and PFOS reported for 713 liver samples across 33 odontocete species spanning 13 countries from 2000 to 2023. Using generalised linear mixed models, we evaluated the effects of genus, location, sex, life stage, and sampling year on PFAS concentrations, combining published datasets with new samples from Australia. Genus and location were the strongest predictors, suggesting that interspecific ecological and physiological traits likely contribute to PFAS accumulation. Concentrations were highest in males and younger individuals, consistent with maternal offloading and possible age-related dilution. Spatio-temporal trends indicate that PFAS contamination is widespread and increasing globally, with highest concentrations reported in the Pacific. This study provides a critical baseline for understanding global PFAS exposure in marine mammals, which underscores the need for coordinated monitoring and further research to address regional data gaps and potential unrecognised biological effects. HighlightsO_LIHigh genus-specific and spatial differences in PFAS contamination across odontocetes globally. C_LIO_LIIncreased contamination in younger/smaller individuals. C_LIO_LISex-specific trends, including higher PFAS levels in male odontocetes. C_LIO_LISpatio-temporal trends suggesting increased PFAS concentration despite global regulatory efforts, with highest concentrations in the Pacific Ocean. C_LI

Saline endorheic shallow playa-lakes are ecosystems susceptible to extreme geochemical changes because of severe hydro-climatic fluctuations. Under dry conditions, a rigid salt crust can separate the underlying sediments from the atmosphere. This interface is an organic-mineral assemblage of benthic biofilm encapsulated by evaporitic salts. It is well known that its structure, composition and consistency control water evaporation from underlying sediments, but its role in CO2 fluxes is unknown. We therefore measured the CO2 exchanges from sediments and the atmosphere in a hypersaline playa-lake characterized by a thin organic-mineral benthic crust upon drying. Results show that the largest CO2 release to the atmosphere occurs when ambient temperature and sediment humidity are high and low respectively. Nonetheless fluxes were lower than those reported for typical dry freshwater sediments and other hypersaline lagoons. The dry crust contains sedimentary structures that likely reflect the gaseous pressure from the underlying sediments, and its removal provokes a significant increase in net CO2 fluxes. Thus, this interface exerts physical control over both water evaporation and gases exchange such as CO2. Nevertheless, prolonged and severe droughts threaten the integrity of the crust: cracks together with bio-induced burrows and tunnels, likely create preferential pathways for CO2 leakage and enhance oxygen diffusion within the sediments and likely promote aerobic heterotrophic activity, explaining the CO2 leakage observed just below the organic-mineral crust.

The accumulation of microorganisms and macroorganisms on aquatic surfaces poses economic and ecological challenges, particularly in maritime transport. Traditional antifouling methods, such as biocidal coatings containing toxic compounds like tributyltin (TBT) and copper, are effective but harmful to the environment. This study investigates eco-friendly antifouling alternatives, focusing on nature-inspired compounds (NIAFs) GBA 26 (GBA) and DPC345DHC (DH345), derived from polyphenols and flavonoids, respectively. The ecotoxicity of these compounds was evaluated using standardized assays with various species, including embryos of Danio rerio (zebrafish) (OECD TG 236), the algae Raphidocelis subcapitata (OECD TG 201), and the bacteria Vibrio fischeri (ISO 11348-2), along with nuclear receptor transactivation assays in Mytilus galloprovincialis (Mediterranean mussel). Gallic acid derivative GBA and 24h-transformation products showed low toxicity in zebrafish embryos, while dihydrochalcone DH345 inflicted developmental toxicity in zebrafish at 1 mg/L and above. Comparatively, tralopyril, a commercial biocide, exhibited significant toxicity at lower concentrations. Transcriptomic analysis of zebrafish embryos treated with GBA revealed selective gene modulation related to stress response, ion transport, and protein synthesis. Both, GBA and DH345, were shown to inhibit algae growth at 0.1 mg/L. Vibrio fischeri assay showed no toxic effects for any of the tested compounds. Nuclear receptor transactivation assays conducted with GBA revealed no activation of PPAR or PXR receptors. These findings suggest GBA and DH345 as potential eco-friendly antifouling agents with lower environmental risks than established antifoulants such as tralopyril. However, further research is needed to evaluate their potential long-term ecological impacts, particularly chronic toxicity across various organisms. This study advances the pursuit of sustainable antifouling solutions that prioritize environmental protection.

Aquatic non-native invasive species are notoriously difficult to eradicate, particularly in pondscapes where populations can spread rapidly, persist in unmanaged refugia, and recolonise treated sites. In such contexts, high-intensity management interventions may be justified, balancing short-term collateral impacts against the prevention of permanent establishment and long-term damages. Chemical eradication methods, such as rotenone or herbicide application, can be effective but raise ethical and environmental concerns. Here, we evaluate quicklime (calcium oxide, CaO) application as a more sustainable alternative control tool for pondscape invaders compared to other chemical methods, using the African clawed frog (Xenopus laevis) invasion in Belgium as a case study. When applied to water, quicklime hydrates exothermically to calcium hydroxide (Ca(OH)), which releases OH ions upon dissolution, temporarily and rapidly increasing pH to lethal levels. In winter 2023, three ponds with breeding populations of X. laevis of low ecological value were drained, fenced, and treated with quicklime. Treatment effectiveness was assessed through pH measurements, visual surveys, and environmental DNA (eDNA) quantification. Immediately after treatment, large numbers of deceased post-metamorphic individuals were recovered, indicating treatment-induced mortality. Eight weeks post-treatment, eDNA concentrations were markedly lower in two of the three ponds (reductions of 100% and 80%) compared to those during the same period one year later. Although eDNA concentrations increased again during the following summer suggesting partial population recovery through survival and/or recolonisation, they remained lower than pre-treatment conditions. Water pH returned to near baseline levels within one month. We provide the first field-based preliminary evidence that quicklime can induce large-scale mortality in X. laevis populations in small to medium-sized ponds. We discuss practical considerations, limitations, and broader applicability, proposing quicklime as a high-intensity option within integrated management strategies for pondscape invaders.

Per- and polyfluoroalkyl substances (PFAS) are manmade chemicals that are persistent in the environment and have been linked to various physiological and neurobehavioral outcomes, including anxiety disorders. Trifluoroacetic acid (TFA), a short chain PFAS and the most common PFAS degradation product, is increasingly detected in water, soil, and human blood, raising significant concerns about its developmental toxicity. However, the impact of early-life TFA exposure on neurodevelopment and behavior remain insufficiently characterized. In this study, we employed Zebrafish (Danio rerio) embryos as a New Approach Methodology (NAM), to evaluate the development, behavior, and protein expression changes in response to early-life TFA exposure. Embryos were exposed to environmentally relevant low and high concentrations of TFA beginning at one-cell stage. Early developmental physiology was assessed by measuring viability, tail twitch response, hatching rates, and chorion diameters during embryogenesis. Anxiety-like behaviors were evaluated at 5- and 6-days post-fertilization using validated behavioral assays such as the Light-Dark Test and Startle Response. Each test evaluates distinct anxiety-related behaviors by measuring locomotor activity, thigmotaxis (wall preference), and stimulus reactivity, with anxious zebrafish larvae showing increased movement in light and greater wall preference. Then to identify molecular pathways underlying observed developmental phenotypes with TFA exposure, proteomic analyses were performed on embryos at 24- and 48-hours post-fertilization. Our results indicate that TFA exposure altered developmental physiology, evidenced by reduced chorion diameters, and lead to increased anxiety-like behaviors with larvae exhibiting thigmotaxis. These phenotypic changes were accompanied by detectable alterations in the embryonic proteome. Collectively, our findings provide insight into how short-chain PFAS exposure during critical windows of development may contribute to neurobehavioral dysfunction, highlighting potential risks relevant to inform public health policies and environmental regulations.

BackgroundContinuous, non-invasive viral surveillance is essential to monitor emerging pathogens and guide public health responses. Most environmental surveillance studies use targeted qPCR approaches, and comparisons between wastewater and indoor air surveillance remain limited. We aimed to compare the utility of emergency department indoor air and urban wastewater for tracking circulating viruses and resolving genomic information. MethodsWe conducted a matched-pair study comparing 19 weekly indoor air samples from the central ventilation exhaust shaft of an emergency department and 19 24-hour composite municipal wastewater samples in Leuven, Belgium, from December 2024 to April 2025. Both sample sets were processed using probe-based hybrid-capture viral metagenomics targeting over 3000 viral species, using influenza A as a clinically relevant test case. FindingsWastewater captured higher overall viral diversity (233 versus 106 species) and more complete genomes compared to indoor air, showing a relatively stable composition, mainly of enteric and animal-associated viruses. Indoor air demonstrated lower overall diversity but was enriched for respiratory viruses, including influenza A, coronaviruses, metapneumovirus, and respiratory syncytial virus, and more frequently achieved high genome coverage for these pathogens. Although both sample types permitted influenza A subtype characterization, influenza A genomes from wastewater were often less well covered. When coverage thresholds were met, indoor air supported targeted antiviral resistance-site screening for influenza A and RSV-A. InterpretationWastewater and indoor air generate distinct but complementary viromes. Wastewater acts as a diverse, population-level monitor for One-Health applications, whereas indoor air serves as a targeted, human-centric sentinel system facilitating further genomic characterization for respiratory viruses. FundingMustafa Karatas is supported by a Research Foundation Flanders (FWO) fundamental research scholarship (number: 11P7I24N). C.G., L.C., E.H., S.G. and E.A. acknowledge support from the DURABLE project. The DURABLE project has been co-funded by the European Union, under the EU4Health Programme (EU4H), project no. 101102733. Research in context Evidence before this studyWe searched PubMed for studies published between Jan 2000 and March 2024 using the terms "wastewater surveillance", "metagenomics", "indoor air", and "viral metagenomics". Previous studies have shown that wastewater surveillance can detect population-level viral circulation, and more recent work has explored indoor air sampling as a method for monitoring respiratory virus transmission. However, environmental metagenomic studies have largely examined these two sample types separately. Furthermore, most studies relied on untargeted sequencing approaches, which often yield fragmented genomes in these environments. To date, no study has systematically compared indoor air and wastewater using a comprehensive hybrid-capture viral metagenomics approach for virus surveillance. Added value of this studyWe conducted a matched comparison of indoor air from a hospital emergency department and municipal wastewater collected during the same weeks in Leuven, Belgium. We analyzed both sample types using an identical hybrid-capture viral metagenomics workflow targeting more than 3000 viral species. This design enabled a direct evaluation of how the two environmental surveillance lenses differ in viral diversity, genomic recovery, and epidemiological relevance. Wastewater captured broader viral diversity and a stable background dominated by enteric and animal-associated viruses, whereas indoor air captured more respiratory viruses and more frequently yielded high genome completeness for these pathogens. When genome coverage thresholds were met, indoor air data enabled influenza subtype identification and screening for antiviral resistance markers. Implications of all the available evidenceOur findings support a layered environmental surveillance strategy in which different environmental samples provide complementary information. Wastewater offers a stable, population-level view of viral circulation and captures broad viral diversity, including human and animal-associated viruses. Indoor air sampling in human-dominated settings provides a more direct signal of respiratory virus circulation and can yield genomes suitable for subtype and mutation-level characterization. Combining these approaches could strengthen metagenomic surveillance frameworks by improving the interpretation of environmental viral signals, supporting early detection of emerging pathogens, and helping distinguish human virus circulation from environmental or animal-derived detections.

Natural freshwater streams harbor diverse microbial communities that support ecosystem functioning. Due to their great biodiversity and geomorphological characteristics, these ecosystems are often very attractive ecotourism destinations, which makes them highly vulnerable to anthropogenic disturbances. The Agua Azul Waterfalls (Cascadas de Agua Azul, in Spanish), a major tourist destination located in indigenous territories of southeastern Mexico (Chiapas, Mexico), offer a unique setting to investigate how sustained human activity influences microbial diversity and quality of water and sediments. To determine the ecological sensitivity of this freshwater stream to tourism pressure, we sampled sites spanning gradients of tourist activity and conducted an integrated analysis of water and sediment physicochemistry, elemental composition, and the composition of microbial communities (bacteria, archaea, and fungi). Areas associated with ecotourism activities showed notable changes in physicochemical parameters and microbial community composition, indicating localized impacts on this ecosystem. Furthermore, evidence of effective management by local Indigenous communities suggests a partial mitigation of anthropogenic disturbances through ecotourism activities. Our findings highlight the potential of microbial diversity in combination with physicochemical parameters as a tool to detect early stages of human impacts on freshwater ecosystems and establish a basis for future monitoring and conservation efforts. The distinctive characteristics of this site position it as a promising model for advancing our understanding of microbial diversity and the dynamics of freshwater stream ecosystems. ImportanceThis study shows evidence that ecotourism is already impacting the biodiversity and water quality of Agua Azul Waterfalls, a freshwater stream located within a protected natural area in southeastern Mexico. While the water still meets basic quality standards, areas with higher tourist activity show early signs of nutrient enrichment and measurable changes in the types of microbes present and the roles they play in this ecosystem. As the first analysis of microbial diversity in this ecosystem, our work highlights the value of microbes as early and sensitive indicators of human impact. By directly comparing tourist and non-tourist areas, we provide evidence of how recreational pressure is transforming this freshwater environment. We expect that our findings will help guide local communities and policymakers in creating more sustainable tourism practices to preserve the cultural and economic value of this ecosystem before irreversible damage occurs.

Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are the main greenhouse gases (GHGs) contributing to the ongoing climate crisis. Among those N2O has the highest global warming potential and is mainly of microbiological origin. Tropical rainforests are considered the primary natural source, although in recent years fluxes of N2O from polar ecosystems have been reported at comparable levels. In this study we aimed to identify High Arctic terrestrial habitats with the highest potential to become sources of N2O emissions. A microbiological and geochemical analysis was performed on soil procured from the biologically and geomorphologically diverse South Spitsbergen region in search of biotic and abiotic determinants of a N2O emission hotspot. Terrestrial sites within this High Arctic area vastly differed in their potential to emit substantial N2O amounts. External organic matter inputs were pivotal in maintaining a pool of inorganic nitrogen compounds for microbially-mediated N2O-generating processes such as denitrification. The examined planktivorous seabird colony presented a unique, potential N2O emission hotspot as it featured persistent acidification of the surrounding soil, a steady ammonia release and nitrate presence even after breeding season closure. Soils of the majority of analyzed sites did not display detectable nitrate and/or ammonia levels, with some areas having the characteristics of a N2O-sink rather than an emitter, especially postglacial moraine deposits. The presented data encourage further, more targeted investigations of High Arctic N2O emission hot- and coldspots to progressively improve N2O emission estimates for permafrost affected regions worldwide.

Sustainable aquaculture requires comprehensive chemical oversight, as compounds used in aquaculture can persist in ecosystems, bioaccumulate through food chains, and affect aquatic life and human health. This study presents ReCAnt (Resource on Chemicals used in Aquaculture and their Ecotoxicity), which compiles information on 690 aquaculture chemicals, with data on toxic effects and therapeutic potential curated from published literature. It was observed that only a fraction of the 690 chemicals are currently regulated, revealing gaps in existing regulations. Integration of data from the Comparative Toxicogenomics Database revealed associations with genes, phenotypes, and diseases, while ECOTOX data provided toxicity and bioconcentration information. Predicted biotransformation pathways and partition coefficients indicated microbial degradation potential and fate across environmental media. Further, food web network analysis identified species vulnerable to trophic transfer and common entry points for chemicals into aquatic ecosystems. This resource can aid in developing evidence-based regulatory frameworks and promoting sustainable chemical management.

Landfill leachates in rapidly urbanizing regions like Dhaka present a complex ecological challenge owing to the concurrent buildup of heavy metals and plastic waste. Despite the severity of this pollution, the role of indigenous multi-functional bacteria in mitigating these mixed contaminants remains poorly understood. This research sought to isolate and characterize bacteria resistant to heavy metals and capable of degrading plastics from the Aminbazar and Matuail landfills and evaluate their bioremediation potential. Physicochemical analysis confirmed extreme contamination, with heavy metal levels (Pb, Cr, Cd, Cu) significantly exceeding WHO safety limits. Out of 81 isolates, nearly half exhibited multi-metal resistance and polyethylene (PE) degradation capacity. Statistical analysis showed a significant correlation between plastic degradation and multi-metal tolerance, suggesting a linked evolutionary adaptation. Enzymatic assays confirmed enzymes (e.g., urease, catalase, citrate and esterase) as drivers of both plastic degradation and heavy metal tolerance in leading isolates. Molecular screening identified the resistance genes pbrA and alkB, while the high prevalence of Class 1 integrons (80% in pbrA-positive isolates) points to a high potential for horizontal gene transfer in these environments. Furthermore, MALDI-TOF MS identified the functional isolates as Bacillus sp. with FTIR verifying the contribution of specific cell-surface functional groups to metal biosorption. These results underscore the promise of native Bacillus strains as promising agents for the development of sustainable, integrated biotechnologies for landfill restoration and complex waste management.

Soils are vital reservoirs of biodiversity and providers of ecosystem services, yet they are increasingly threatened by agricultural intensification and pesticide use. Residues often persist as complex mixtures, while environmental risk assessment still largely focuses on single substances, potentially underestimating mixture effects. Earthworms play a key role in soil functioning and are particularly vulnerable to pesticide contamination. We investigated the effects of a binary mixture of epoxiconazole and imidacloprid, two persistent and frequently detected pesticides, on life-history traits of Aporrectodea caliginosa. We estimated each compound relative potency using dose-response experiments on juvenile growth and cocoon production. Next, we assessed the potential for synergy or antagonism in a fixed-ratio ray design including five concentration ratios and seven additive isoboles (36 conditions). Both compounds showed significant toxicity. Imidacloprid showed high potency (juvenile growth NOEC = 0.28 mg/kg; reproduction EC50 = 0.55 mg/kg), whereas epoxiconazole had moderate effects (juvenile growth NOEC = 9.3 mg/kg; reproduction EC50 = 126.8 mg/kg). Reproductive endpoints were more sensitive than adult growth, with juvenile growth being the most sensitive overall. Mixture analysis using Jonkers models revealed significant deviation from Independent Action only under the simple interaction model, indicating synergism, consistent with cytochrome P450 interference reported in other taxa. Field-reported imidacloprid concentrations often approach effect thresholds, suggesting potential risks for earthworm populations. Overall, the combined effects of epoxiconazole and imidacloprid may exceed predictions not taking interactions into account. These results highlight the need to incorporate pesticide mixture effects into environmental risk assessment. Environmental ImplicationsPesticide residues persist in agricultural soils as complex mixtures, yet risk assessment still focuses mainly on single substances. This study shows that the combined effects of imidacloprid and epoxiconazole on earthworm reproduction can exceed predictions based on Independent Action, with evidence of synergistic interactions. Effect thresholds for imidacloprid approach reported maximum environmental concentrations, indicating limited safety margins for soil organisms. These findings suggest that mixture exposures may pose greater ecological risks than currently anticipated and highlight the need to integrate pesticide mixture toxicity and potential synergism into environmental risk assessment frameworks. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=116 SRC="FIGDIR/small/707680v1_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@18c89ceorg.highwire.dtl.DTLVardef@1ab4dd2org.highwire.dtl.DTLVardef@1823edaorg.highwire.dtl.DTLVardef@1ec9782_HPS_FORMAT_FIGEXP M_FIG C_FIG

The use of field water for laboratory rearing of mosquitoes could offer a better representation of the natural aquatic environment than laboratory tap or deionised water. For logistical reasons, such water may be stored in the laboratory environment for an extended period, but its stability is poorly documented. This study evaluated the influence of laboratory storage conditions on the kinetics of physicochemical parameters of breeding water collected from a field habitat. To capture within-habitat variability, water was collected from multiple spatial points from a breeding site and transferred into plastic containers for storage under laboratory conditions. Water physicochemical parameters were measured in the field to establish baseline readings, while laboratory measurements were done at 2-3-day intervals over 2 months to evaluate temporal changes. A linear mixed-effects model was fitted to evaluate the determinants of changes in physicochemical parameters under laboratory storage. Most parameters exhibited high stability; however, water temperature increased significantly by an average of [~]1.5 (p= 0.046) relative to the field. Water pH demonstrated a long-term rise over the 2-month storage period with a transient, significant dip of 0.71 units after a week of storage (p< 0.001). Overall, LMM analyses revealed that ambient relative humidity was the strongest statistical predictor of change in all water parameters except pH (p< 0.05). Ambient temperature correlated positively with water temperature and ammonium nitrogen (NH4-N) (p<0.002), and negatively with dissolved oxygen (p< 0.002). These results indicate that stored field water is highly sensitive to the laboratory microclimate. Specifically, water temperature, pH, and NH4-N serve as candidate indicators for storage-related physicochemical drift. We recommend the rigorous standardisation of insectary humidity and temperature, and monitoring of water parameters, which are likely relevant for bioassay reproducibility.

We present findings from the first known pilot study of transatlantic airplane wastewater monitoring, conducted over six months at two connected international airports in the United States and the United Kingdom. This study demonstrates the feasibility of implementing bilateral wastewater-based pathogen surveillance at international travel hubs. We outline the operational and analytical methodologies employed, highlight key challenges encountered in transnational coordination, and provide recommendations for the design and implementation of future surveillance programs at points of entry.