Earth and Environmental Sciences

Intensified industrialization, urbanization, and agricultural activities have led to excessive heavy-metal accumulation in agricultural products, threatening food safety. Recent studies suggest that foliar exposure under atmospheric deposition is the dominant route for controlling metal accumulation in edible tissues. However, their specific mechanisms remain poorly understood. This Review synthesizes the foliar uptake and translocation of atmospheric heavy metals, focusing on the interactions among particle size, metal speciation, and leaf morphology. Key debates include the form of entry (ionic vs particulate), the mechanism of uptake (passive vs active), and the transporters involved. Emerging evidence shows that micrometer-sized particles enter leaves through stomata via passive diffusion, although intracellular transport may involve active mechanisms. In contrast, nanosized particles can penetrate both cuticular and stomatal pathways. Notably, leaves preferentially take up ionic heavy metals over particulate forms. The trichome pathway emerged as an additional route. However, whether it governs direct uptake or enhanced retention and if the chemical form taken up is ionic or particulate remains elusive. Specific transporters that mediate translocation to edible tissues have not yet been identified. This review represents a paradigm shift in crop safety, moving beyond the traditional root uptake perspective to foliar uptake of atmospheric matter.

Abstract Urban environments expand in both population and area, stressing the need for means to study and understand urban green spaces (UGS) in a comprehensive manner. Especially tree-covered UGS are central to biogenic carbon (C) sequestration in cities, as well as for the many other ecosystem services they provide. However, many modelling applications used to study them have certain limitations, for instance related to inaccurate representation of tree stand development over time or considering the effects of changing climate. In this study, we examined the applicability of a non-urban forest growth and C balance model PREBASSO to simulating tree-covered UGS at a set of study sites in Southern Finland. We also investigated both the potential of acquiring tree stand composition from airborne laser scanning (ALS) data and the role of uncertainty in soil conditions in the model results. In doing so, we aimed to address some data limitations typical for urban areas and provide new tools for studying the development of C sequestration of tree-covered UGS in the future. Our results showed that the modelling approach effectively captured the phenology of C sequestration when evaluated against satellite-observed leaf area index time series. However, the model tended to underestimate peak leaf area index and frequently overestimate annual tree height growth. C sequestration was particularly sensitive to the assigned forest site type and to assumptions related to soil C stock and water holding properties. The simulations further indicated that younger forest stands may exhibit higher increase in C sequestration in future conditions. Together, these findings both demonstrated the promise of the assessed model in representing tree-covered UGS and highlighted several avenues for methodological improvement.

Abstract Climate shocks challenge the imagined social contracts between urban residents and city administrators, potentially resulting in declining public trust and a reluctance to engage in collaborative adaptation. Drawing from interviews and questionnaire responses, this study explores how relatively affluent residents of Cape Town, South Africa, responded to the severe 2017–2018 drought. The study illustrates how climate-induced stresses can serve as inflection points in urban social contracts, mediated by the availability of modular technologies and infrastructure, with implications for governance, equity, and the future of public trust in service delivery. For cities seeking to maintain the terms of established social contracts, these findings underscore a need to communicate roles and responsibilities clearly, ensure fair cost distributions, and to invest in public trust to ensure continued collaborative engagement, even among those who can afford autonomy.

Nanoplastics (NPs) represent an emerging threat to aquatic ecosystems. However, their transgenerational transfer potential and associated toxicological consequences remain poorly characterized. In this study, the transgenerational transfer of polystyrene (PS) NPs was quantified and visualized in the floating macrophyte Spirodela polyrhiza using the metal-doped and bioimaging method. Beyond parental (F0) S. polyrhiza uptake via frond lower epidermis, PS accumulated through stipule-mediated mother-to-daughter frond transfer (MF-to-DF transfer) with an efficiency of 1–3%. Both F0 uptake and MF-to-DF transfer were insensitive to environmentally relevant PS weathering. The F1-to-F2 transfer efficiency exhibited a clear dose-dependent increase, rising from 0.2 to 0.6% at 0.1 mg L–1 to 0.7–1.1% at 5 mg L–1. Notably, a pronounced F2-specific phytotoxicity emerged, which was closely correlated with reduced growth (9 ± 4% lower specific growth rate) and frond number (12 ± 7% decline), whereas no comparable inhibition was observed in F1. Mechanistically, this phytotoxicity stemmed from transcriptional reprogramming (dysregulated circadian/photosynthesis-antenna pathways, activated stress resistance metabolites) at 5 mg L–1. These findings established that parental NP exposure could induce transgenerational growth inhibition in unexposed offspring; however, the extent to which these mechanistic observations apply to environmental scenarios (e.g., 0.1 mg L–1) remains to be determined. This represented a significant yet under-characterized ecotoxicological risk, and it critically escalated NP impacts from individual-level toxicity to population-relevant consequences in aquatic ecosystems.

Electric utilities face a growing challenge in maintaining low-cost and reliable electricity amidst emerging pressures for socio-environmental sustainability and reduction of greenhouse gas (GHG) emissions. In this work, we introduce an approach for generation expansion planning (GEP) that prioritizes sustainability objectives by implementing planning strategies that constrain future generation options based on socio-environmental indicators. Capacity expansion decisions under each strategy are then simulated and evaluated under a wide range of possible futures. Using the Temoa energy system optimization model, we adopt a unique myopic foresight approach in which cost-optimal capacity expansion decisions are locked-in based on forecasts of the future, before actual values are revealed. We demonstrate this approach for a case study in the Yukon, Canada, by identifying robust strategies with respect to cost, reliability, GHG emissions, ecological sustainability, and social sustainability. In our case study, more flexible strategies, such as restricting the development of diesel generation but not other types of thermal generation, improve socio-environmental outcomes at relatively low risk to system cost. Conversely, more restrictive strategies, such as avoiding all projects with potentially negative social or ecological impacts, risk substantially increasing system costs and may even have the opposite intended effect by inducing reliance on emergency diesel generators.

Environmental chemical effects of low-frequency mechanical energy deserve attention, yet its role has been traditionally regarded as a physical process. Using a remarkably simple beaker-stirrer system without any external catalyst, we demonstrated the contact-electro-catalysis (CEC) degradation of various organic pollutants via mechanical stirring. Specifically, malachite green (20 μmol L–1) was completely degraded within 5 h (k = 0.68 h–1), while a series of emerging contaminants could also be removed to varying extents within 12 h. The organic pollutant degradation was attributed to the reactive oxygen species (·OH, ·O2–, and 1O2) generated at the reactor wall–solution interface by CEC. Furthermore, degradation performance depended on triboelectric properties of reactor materials (polytetrafluoroethylene > polystyrene > stainless steel > glass) and hydrodynamic conditions (rotation rate and impeller diameter). Increasing rotation rate or impeller diameter enhanced mechanical energy input (Reynolds number and turbulent kinetic energy), then increased the average interfacial mechanical force (resultant traction force), and thereby promoted CEC. This work proposed that low-frequency mechanical energy provided by the prevalent hydraulic processes in nature may drive degradation of organic pollutants at natural solid/liquid catalytic interfaces, thus providing an innovative explanation of natural water self-purification through a chemical process.

Abstract Thorium‐rich (Th‐rich) geological units have been detected by remote sensing in the Martian crust. However, there is still a lack of mineralogical evidence to constrain the magmatic processes responsible for these anomalies. In this study, we report the first discovery of thorite (ThSiO 4 ) grains within a zircon fragment from Martian regolith breccia meteorite NWA 11220. These zircon‐hosted thorite grains are micron‐sized (<5 μm) individual particles and are associated with magnetite and ilmenite inclusions. Transmission Electron Microscopy analysis shows that the thorite and zircon have become metamict due to radioactive decay, whereas magnetite and ilmenite remain crystalline. This metamict thorite provides mineralogical evidence for a highly evolved, Th‐saturated, and oxidized magmatism on Mars. Furthermore, our findings offer a critical ground‐truth for orbital Th anomalies and provide new insights into thorium reservoirs in the Martian crust.

This article presents the results of a field study conducted in 2022 on groundwater outflows located at the edge of the Kashubian Lake District and the Reda-Łeba Proglacial Stream Valley in northern Poland. The recharge of numerous springs was found to occur from the first aquifer, locally supported by a deeper aquifer connected to the first one near the bowl of Lubowidzkie Lake. Groundwater drainage occurs by gravity. It is relatively abundant for young glacial areas and averages 82 dm3·s−1, making the springs capable of acting as a drinking water reservoir. This assessment is based on major ions and nutrients only; microbiological and trace-organic/metal analyses are required before any drinking-water designation. Spring water is important in the lake’s supply, accounting for 18.0% of the total inflow to the basin. The hydrochemical characteristics of these waters keep the lake in ecological balance. The waters from the springs are characterized by little variation in chemical composition, with the Ca-HCO3 hydrochemical type. They represent young infiltration waters associated with direct recharge from precipitation (the average age of the water is 60 years). Currently, low nitrate and chloride suggest limited agricultural and urban influence, but phosphate levels and observed human activities warrant caution. Forest management is gradually developing in its catchment, which may result in a reduction of the spring yield and a deterioration of their quality in the future. This may result in a disturbance of the hydrological balance of structures hydraulically connected to spring recharge and to groundwater inflow (river, lake). Although the springs studied are local hydrological phenomena, their functioning and the need for protection are closely linked to global challenges in the field of sustainable development. This primarily concerns the protection of groundwater-dependent ecosystems and, more broadly, water security and increased resilience to climate change.

= 144) living near sites of historical agricultural biosolids application. All participants had PFAS concentrations measured in their private drinking well water by the Maine Department of Environmental Protection from 2020 to 2023. In late 2023, we measured serum PFAS concentrations and administered a survey on water-related, occupational/recreational, residential, local food intake, and sociodemographic/health characteristics. We used multivariable linear mixed-effects models to examine associations of each predictor with serum concentrations of perfluorohexanesulfonic acid (PFHxS), perfluorooctanesulfonic acid, perfluorooctanoic acid (PFOA), perfluorononanoic acid, and perfluorodecanoic acid. Daily PFAS water intake was the strongest predictor of each serum PFAS, explaining between 22% (PFHxS) and 40% (PFOA) of the variance. Males, postmenopausal females, frequent consumers of local eggs, and those who worked with biosolids on a farm or in another capacity also had higher concentrations of select PFAS than other participants. Together, the predictors studied explained 38-52% of the total variance in serum concentration of each PFAS. Future studies will help further investigate local egg consumption and working with biosolids to inform mitigation strategies in biosolid-impacted communities.

Adaptive behaviors emerge in novel environments through functional changes in neural circuits. While relationships between circuit function and behavior are well studied, how evolution shapes circuits to drive behavioral adaptation is poorly understood. The Mexican cavefish, Astyanax mexicanus , provides a unique genetically tractable model, with above ground eyed surface fish and multiple blind cavefish populations that have evolved in darkness. These differences in environment and vision offer a way to examine how neural circuits evolve. We examine differences in detection and behavioral responses to the nonvisual effects of light in cave and surface A. mexicanus . Both populations exhibit photokinesis: Surface fish become hyperactive after darkness, and cavefish after illumination. Using whole-brain functional imaging aligned to an established Astyanax brain atlas, we identify the caudal posterior tuberculum as key to light- and dark-induced photokinesis. Pan-neuronal GCaMP imaging shows that dark-sensitive neurons in surface fish are light-sensitive in cavefish. Light sensing depends on dopamine signaling, suggesting that a conserved dopamine circuit mediates photokinesis and highlighting Astyanax as a model for sensory adaptation.