Environments

17 pages, 7941 KB

Open AccessArticle

A Quantitative Method for Estimating Spatial Uncertainty of Urban Rooftop Winds

by Ziv Klausner and Eyal Fattal

Environments 2026, 13(7), 377; https://doi.org/10.3390/environments13070377 - 2 Jul 2026

The wind field in urban areas is characterized by an inherent spatial variability, which is also termed spatial uncertainty. This may be manifested as a noticeable difference between rooftop-level measurements in adjacent locations, the degree of which changes throughout the day. In meteorological [...] Read more.

The wind field in urban areas is characterized by an inherent spatial variability, which is also termed spatial uncertainty. This may be manifested as a noticeable difference between rooftop-level measurements in adjacent locations, the degree of which changes throughout the day. In meteorological and environmental contexts, such uncertainty is often described as a probability distribution. Usually, studies deal with the uncertainty of each wind vector component separately, i.e., wind speed and direction. The uncertainty is assumed to be distributed symmetrically around the mean and represented by a single characteristic value. Such representation neglects the correlation between the two wind vector components together. This, in turn, may result in wind vector component combinations that are physically inconsistent with realistic wind regimes. This study proposes a method that quantifies the spatial uncertainty of the urban rooftop wind. It is based on a covariance matrix that quantifies the relationship between the rooftop spatial wind components alongside the seasonal Mahalanobis distance functions. It draws on a representative sample of weather stations and previously calculated seasonal log-logistic Mahalanobis distance functions. Thus, an elliptic-shaped tolerance region is calculated to quantitatively estimate a given proportion of the possible values of the wind vectors at a given time. The model was demonstrated on the metropolitan area of Tel Aviv. The results show that the spatial wind distribution can be very well represented by a small sample of merely four stations. The model’s results were found to be well within the confidence interval, leading to the conclusion that the model is fully capable of providing an accurate description of the current state of the urban wind field. Full article

(This article belongs to the Special Issue Advances in Urban Air Pollution, 3rd Edition)

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20 pages, 15192 KB

Open AccessArticle

Karrikinolide Maximises Seed Use Efficiency for Ecosystem Restoration and Nature Repair

by Abhishek Bajpai, Namratha Biddanda Ganapathi, Georgina McGregor, Kenneth Tryggestad, Melinda Pickup, Colin Saltmere and Jitka Kochanek

Environments 2026, 13(7), 376; https://doi.org/10.3390/environments13070376 - 2 Jul 2026

Abstract

Ecological restoration and nature repair combat ecosystem and land degradation, biodiversity loss and climate change. Yet seedling recruitment failure and perilously low plant survival (6–11%, often less) result in mass seed wastage. To increase seed use efficiency for restoration, the germination stimulant karrikinolide [...] Read more.

Ecological restoration and nature repair combat ecosystem and land degradation, biodiversity loss and climate change. Yet seedling recruitment failure and perilously low plant survival (6–11%, often less) result in mass seed wastage. To increase seed use efficiency for restoration, the germination stimulant karrikinolide or KAR₁ (3-methyl-2H-furo[2,3-c]pyran-2-one) was evaluated for on-demand seed germination, seedling establishment and plant survival in Australian core restoration species. Our research demonstrated that KAR₁ promoted on-demand germination in 82% of species across nine families. We also showed improved germination outcomes in stored and aged seeds and greater seedling establishment and plant survival in soil after KAR₁ treatment. The commercially available stimulant, gibberellic acid (GA₃), provided no assistance beyond seed germination, suggesting KAR₁ cannot be readily substituted. We recommend that KAR₁ has the potential to meaningfully enhance large-scale seed use efficiency for restoration once challenges like cost and KAR₁ delivery issues are overcome. Full article

(This article belongs to the Section Biodiversity, Ecological Understanding and Conservation)

31 pages, 8840 KB

Open AccessReview

Mechanisms and Effectiveness of Biochar, Zeolite and Attapulgite for Heavy Metal Immobilization in Soils: A Comparative Review

by Anna Derstila, Alkiviadis Stamatakis, Traianos Minos and Evangelia E. Golia

Environments 2026, 13(7), 375; https://doi.org/10.3390/environments13070375 (registering DOI) - 2 Jul 2026

Abstract

Heavy metal contamination of soils represents a persistent environmental challenge, for which in situ immobilization has emerged as a cost-effective and technically viable alternative to conventional invasive remediation technologies. This review comparatively evaluates three distinct categories of soil amendments—biochar, zeolite and attapulgite—within a [...] Read more.

Heavy metal contamination of soils represents a persistent environmental challenge, for which in situ immobilization has emerged as a cost-effective and technically viable alternative to conventional invasive remediation technologies. This review comparatively evaluates three distinct categories of soil amendments—biochar, zeolite and attapulgite—within a unified analytical framework integrating extractable fractions (TCLP, DTPA, and CaCl₂) and geochemical fractionation approaches (BCR and Tessier). The novelty of this study lies in the systematic assessment of the dominant immobilization mechanisms associated with each amendment in relation to soil properties and the chemical speciation of the target metal, as well as in distinguishing between an apparent reduction in metal extractability and a genuine shift toward more stable geochemical fractions. The findings identify ion exchange as the primary immobilization mechanism in zeolites (NaA zeolite, 1–5% w/w, 96% reduction in TCLP-extractable Pb and 91% reduction in TCLP-extractable Cd), the synergistic action of adsorption, complexation, and precipitation in biochar systems (manure-derived biochar, 0–5% w/w, 97.4% reduction in the exchangeable Pb fraction according to the Tessier scheme), and the critical role of surface modification in attapulgite-based amendments (C-ATP, 4% w/w, 95.1% and 74.3% reductions in TCLP-extractable Pb and Cd, respectively). Because these efficiencies were obtained using different extraction protocols, they are not directly comparable. At the same time, cases of adverse responses were identified, including increased As extractability following the application of phosphate-modified biochar and the redistribution of Pb and Cd after amendment with natural zeolite in industrially contaminated soil. These observations highlight that amendment performance is not an intrinsic property of the material itself, but rather the outcome of specific geochemical interactions occurring within the soil system. Increased soil pH emerged as the principal common factor promoting metal stabilization across all amendment categories, whereas substantial variability in amendment dosage, incubation period, and analytical methodology limited direct quantitative comparisons among studies. Consequently, the selection of an appropriate soil amendment should be based on the integrated evaluation of soil physicochemical properties, contaminant speciation, and the intended scale of application, supported by long-term monitoring under field conditions. Full article

(This article belongs to the Special Issue Advances in Heavy Metal Remediation Technologies)

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13 pages, 867 KB

Open AccessArticle

Complementary eDNA Markers Reveal Fish Biodiversity Patterns Across Environmental Gradients in a High-Andean River System

by Manhiro Flores-Iwasaki, Roberto Carlos Mori-Zabarburú, Armstrong B. Fernández-Jeri, Lucas D. Muñoz-Astecker, Sivmny V. Valqui-Reina, Eisen Carlos Usquiza Cruz, Jorge A. Condori-Apfata and Angel David Hernández-Amasifuen

Environments 2026, 13(7), 374; https://doi.org/10.3390/environments13070374 (registering DOI) - 2 Jul 2026

Abstract

This study represents the first comprehensive characterization of fish biodiversity in the Sonche Canyon (northeastern Peru) using environmental DNA (eDNA), revealing a community of 19 taxa whose detection depended critically on a multi-marker approach. The analysis demonstrated that the use of both Metafish [...] Read more.

This study represents the first comprehensive characterization of fish biodiversity in the Sonche Canyon (northeastern Peru) using environmental DNA (eDNA), revealing a community of 19 taxa whose detection depended critically on a multi-marker approach. The analysis demonstrated that the use of both Metafish and Mifish-U PCR primer pairs generated a high complementarity index (0.53), allowing the capture of divergent biological signals; Metafish was essential for identifying characiformes; while Mifish-U revealed the presence of specific gymnotiformes and loricariids. The findings, supported by rarification curves confirming sampling saturation. Principal Component Analysis (PCA) revealed co-variation between the biodiversity “hotspot” in Tingorbamba and elevated nitrate concentration (6.1 mg/L), as well as the ubiquitous presence of the invasive species Oncorhynchus mykiss. In conclusion, the utility of the molecular markers and the observed co-variation between physicochemical variables and species distributions underscore the need for standardized protocols for the monitoring and conservation of fauna in the vulnerable lotic systems of the Peruvian Andes. Full article

(This article belongs to the Section Biodiversity, Ecological Understanding and Conservation)

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55 pages, 16762 KB

Open AccessReview

Phytotechnology for Per- and Polyfluoroalkyl Substances (PFAS) Treatment: Mechanistic Insights into Environmental Behavior, Plant Uptake, and Phytomanagement Opportunities

by Setyo Budi Kurniawan, Suriya Vathi Subramanian, Hassimi Abu Hasan, Hanies Ambarsari, Dian Andriani, Nurfitri Abdul Gafur, Meidaliyantisyah, Fitri Yola Amandita, Tuti Suryati, Rina Andriyani, Arina Yuthi Apriyana, Ekaputra Agung Priantoro, Dominikus Hariawan Akhadi, Tarzan Sembiring and Muhammad Fauzul Imron

Environments 2026, 13(7), 373; https://doi.org/10.3390/environments13070373 - 1 Jul 2026

Abstract

Per- and polyfluoroalkyl substances (PFAS) are ultra-persistent contaminants characterized by exceptional chemical stability, high mobility, and widespread environmental occurrence, posing significant challenges for remediation. Phytotechnology has emerged as a promising nature-based approach, yet its effectiveness is strongly governed by PFAS physicochemical properties and [...] Read more.

Per- and polyfluoroalkyl substances (PFAS) are ultra-persistent contaminants characterized by exceptional chemical stability, high mobility, and widespread environmental occurrence, posing significant challenges for remediation. Phytotechnology has emerged as a promising nature-based approach, yet its effectiveness is strongly governed by PFAS physicochemical properties and plant–soil interactions. This review provides a mechanistic synthesis linking PFAS environmental behavior with phytotechnology performance by examining PFAS sources, transport pathways, and structure-dependent properties that control persistence, partitioning, and mobility, with an emphasis on differences between short- and long-chain compounds. These characteristics determine bioavailability and influence treatment outcomes. Plant uptake mechanisms, including root absorption, xylem translocation, and tissue accumulation, are discussed alongside rhizosphere processes such as sorption, microbial interactions, and hydrological dynamics that regulate PFAS retention and redistribution. Current evidence indicates that phytotechnology functions primarily as a form of phytomanagement rather than a destructive solution, as mineralization is limited and field-scale treatment remains low. Instead, plant–soil–microbe systems reduce PFAS mobility and exposure through stabilization and sequestration. Future research should prioritize strategies for short-chain PFAS, integration with sorptive amendments, and data-driven approaches to optimize phytomanagement performance. Full article

(This article belongs to the Section Environmental Pollution, Toxicology and Restoration)

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33 pages, 20364 KB

Open AccessArticle

Seasonal Variability of Potentially Toxic Elements (PTEs) in Road Dust from Mexico City: Source Identification, Particle Characterization, and Lung Bioaccessibility

by Benedetto Schiavo, Diana María Meza-Figueroa, Claudio Inguaggiato, Ofelia Morton-Bermea, Daisy Valera-Fernández, Belem González-Grijalva, Francisco Berrellez-Reyes and Elizabeth Hernández-Álvarez

Environments 2026, 13(7), 372; https://doi.org/10.3390/environments13070372 - 1 Jul 2026

Abstract

Road dust is an important urban reservoir of potentially toxic elements (PTEs) and a relevant source of human exposure through resuspension and inhalation, particularly in large megacities. This study provides an integrated assessment of the seasonal variability, contamination levels, source identification, particle characteristics, [...] Read more.

Road dust is an important urban reservoir of potentially toxic elements (PTEs) and a relevant source of human exposure through resuspension and inhalation, particularly in large megacities. This study provides an integrated assessment of the seasonal variability, contamination levels, source identification, particle characteristics, lung bioaccessibility, and health risk of road dust in Mexico City, one of the world’s largest urban centers. A total of 74 road dust samples were collected during the dry and wet seasons, and V, Cr, Mn, Co, Ni, Cu, As, Cd, Sb, and Pb were analyzed by ICP–MS in the <20 µm fraction. Geochemical indices, spatial analysis, Pearson correlation, principal component analysis, SEM–EDS particle characterization, in vitro lung bioaccessibility (ALF), and human health risk models were applied. Sb, Cu, and Pb were identified as the most enriched elements, exceeded local background concentrations at all sampling sites. Spatial patterns revealed recurrent hotspots in the northern, northeastern, and central sectors of the city. SEM–EDS analyses showed that most particles belonged to the 2.5–5 µm equivalent-size class and included Fe-rich spherules, Pb-rich aggregates, silicate grains, and C-rich particles. Health risk assessment indicated acceptable risks for adults, whereas children exceeded the non-carcinogenic threshold (HI = 3.85–4.60) and slightly surpassed the upper acceptable carcinogenic risk level. Lung bioaccessibility results revealed low Pb solubility but high mobility of Ni and Cu, with some samples reaching complete dissolution under ALF conditions. These findings demonstrate that traffic-derived road dust represents a persistent urban exposure pathway in Mexico City and highlight the importance of integrating total concentrations, particle characteristics, and bioaccessibility data to improve environmental and health-risk assessments in urban environments. Full article

(This article belongs to the Special Issue Environmental Pollution Exposure and Its Human Health Risks)

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21 pages, 15152 KB

Open AccessArticle

Disentangling pH and Salinity Effects in Biochars Used as Peat Substitutes: Insights from Water Washing and Tomato Plant Growth Responses

by José María García de Castro Barragán, Álvaro F. García-Rodríguez, María Elena Fernández Boy and Heike Knicker

Environments 2026, 13(7), 371; https://doi.org/10.3390/environments13070371 - 1 Jul 2026

Abstract

This study evaluated the effects of water washing on the properties of biochars produced from tomato greens (TB) and vineyard pruning (VB), and examined how these changes influence plant performance in biochar–peat substrates. A 31-day pot experiment was conducted using tomato plants ( [...] Read more.

This study evaluated the effects of water washing on the properties of biochars produced from tomato greens (TB) and vineyard pruning (VB), and examined how these changes influence plant performance in biochar–peat substrates. A 31-day pot experiment was conducted using tomato plants (Solanum lycopersicum L.) grown on biochar/peat mixtures at a 60:40 (v/v) ratio. Fresh biochars (TB 0, VB 0) and biochars subjected to one (TB 1, VB 1) or two (TB 2, VB 2) washings were assessed. Washing substantially reduced pH from 10 to 9 in both materials. The electrical conductivity (EC) and salt content of TB 0 (9147 ± 96 μS cm⁻¹) were markedly higher than those of VB 0 (1539 ± 33 μS cm⁻¹). Successive washing effectively lowered EC to 1019 ± 18 µS cm⁻¹ and 75.4 ± 4 μS cm⁻¹, respectively. Plant performance improved significantly as salinity decreased. Statistical analyses indicated a stronger influence of EC than pH on plant growth. Reduced germination was primarily associated with osmotic stress caused by elevated concentrations of soluble salts, particularly Na, K, Ca, Cl, and S. Biomass production was negatively correlated with these ions. Only Ca and K exhibited significant negative relationships, suggesting that nutrient antagonism may also have contributed to growth inhibition. These findings demonstrate that water washing is an effective strategy for enhancing the horticultural suitability of salt-rich biochars. Salinity, rather than alkalinity alone, appears to be the principal constraint limiting their use as peat substitutes. Washing therefore broadens the potential application of salt-rich green waste-derived biochars in horticultural substrates, supporting peat conservation and circular-economy approaches to organic waste valorization. Full article

(This article belongs to the Special Issue Preparation and Application of Biochar (Second Edition))

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13 pages, 269 KB

Open AccessArticle

A Prognostic Algorithm for Heat-Related Mortality in Older Adults: Development in Milan

by Daria Russo, Sara Tunesi, Maria Teresa Greco and Antonio Giampiero Russo

Environments 2026, 13(7), 370; https://doi.org/10.3390/environments13070370 - 1 Jul 2026

Abstract

Climate change is increasing the frequency and intensity of heatwaves, with substantial health impacts and higher mortality among vulnerable groups including older adults and individuals with chronic diseases. Risk stratification tools may support public health systems in identifying high-risk individuals and implementing targeted [...] Read more.

Climate change is increasing the frequency and intensity of heatwaves, with substantial health impacts and higher mortality among vulnerable groups including older adults and individuals with chronic diseases. Risk stratification tools may support public health systems in identifying high-risk individuals and implementing targeted preventive interventions. This population-based study included Milan residents aged ≥75 years during the summers of 2022–2023 and aimed to test an algorithm for stratifying heat-related health risk. By combining individuals’ classification as ill, treated, and deprived, four heat-related risk levels were defined. The algorithm was developed on the 2022 cohort and validated on the 2023 cohort. A logistic regression model with cross-validation was used, and performance was assessed using AUC, calibration, and Brier score. A total of 192,063 (2022) and 181,509 (2023) residents aged ≥75 years were included. Approximately 56% were classified as high or very high risk, with slightly higher proportions in 2023. Mortality increased with risk level and multimorbidity. The model showed good overall accuracy, fair discrimination, and good calibration in the development cohort. Higher mortality was associated with male, older age (≥85 years), and higher risk strata, while living alone showed inconsistent associations. This prognostic algorithm may contribute to the stratification of heat-related mortality risk among older adults and could support targeted prevention and timely responses to heatwave. Full article

(This article belongs to the Section Society, Environment, Health)

37 pages, 2918 KB

Open AccessArticle

Soil Contamination Around an Iron Ore Mining and Beneficiation Complex in the Semiarid Zone of Northern Kazakhstan

by Aliya Yskak, Seitbek Kuanushbayev, Zhumash Bekmyrza, Zhassulan Irzhanov, Almabek Nugmanov, Gulnaz Yermoldina, Assel Tokusheva, Vladimir Fominov, Aleksandr Bulaev, Petr Lyanga, Kuanysh Zhumalynov and Zheniskul Bozhekenova

Environments 2026, 13(7), 369; https://doi.org/10.3390/environments13070369 - 30 Jun 2026

Abstract

Soil contamination around iron ore complexes in semiarid zones is usually described by total metal concentrations, which underestimate the labile mobile pool. At the Sokolovka-Sarbai mining and beneficiation complex (SSGPO, Northern Kazakhstan), total (EPA 3051A) and mobile (neutral NH₄OAc, pH 7) [...] Read more.

Soil contamination around iron ore complexes in semiarid zones is usually described by total metal concentrations, which underestimate the labile mobile pool. At the Sokolovka-Sarbai mining and beneficiation complex (SSGPO, Northern Kazakhstan), total (EPA 3051A) and mobile (neutral NH₄OAc, pH 7) forms of ten heavy metals were analyzed in 87 site-horizon composites (29 sites × 3 pits × 3 horizons; 261 field samples). Descriptive indices flag Co as the only moderately contaminated element (I_geo 1.16) and Mn as the only one in persistent deficit (Kc_total 0.62); Co and Mn show the largest mobility-factor increments above background (Δ_MF +17.8 and +22.3 p.p.). The priority toxic elements As, Cd and Pb remain at or near depth-matched background in the total fraction (median Kc_total 0.98–1.09; I_geo < 0 for all three), although Pb shows a moderate mobile-fraction enrichment (median Kc_mobile 2.6); mercury was not among the ten metals analyzed. Factor analysis of mobile forms resolves two independent sources (F1-siderophile Cr-Ni-Fe-Mn-Co; F2-Zn-dominant, non-sphalerite) and a humus-driven sorption pool (F3), coherently localized in the dump2A-pit2 sector; mobile-fraction attribution greatly outperforms the total fraction (21 vs. 0 FDR-significant trends). The raw Mn-deficit-Co-mobility correlation (ρ = −0.54) is fully mediated by humus (partial ρ = +0.05). Total Mn deficit and enhanced Co lability are therefore interpreted as coupled consequences of a single humus-Ca-pH Kastanozem geochemistry rather than a causal “Mn-buffer depletion → Co mobilization” chain. Because the dataset is cross-sectional, this distinction remains correlational; sequential fractionation and mineralogical verification are priorities for future work. Full article

(This article belongs to the Section Environmental Pollution, Toxicology and Restoration)

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17 pages, 3876 KB

Open AccessArticle

Data-Driven Surrogate Modelling for Industrial Scale-Up of Packed Bed Columns Using Residual Biomass for Pb(II) Removal

by Oscar E. Coronado-Hernández, Angel Villabona-Ortíz, Mauricio J. Rosso-Pinto, Candelaria Tejada-Tovar and José Quevedo-Cabarcas

Environments 2026, 13(7), 368; https://doi.org/10.3390/environments13070368 - 30 Jun 2026

Abstract

Pb(II) is a potentially toxic element that can cause problems in the respiratory, digestive, and nervous systems; it can also cause cancer. Most studies have been conducted primarily in the laboratory; therefore, it is necessary to find a way to predict performance on [...] Read more.

Pb(II) is a potentially toxic element that can cause problems in the respiratory, digestive, and nervous systems; it can also cause cancer. Most studies have been conducted primarily in the laboratory; therefore, it is necessary to find a way to predict performance on a large scale. Taking this into account, the objective of this study was to simulate an industrial-scale packed adsorption column for the removal of Pb(II) using Dioscorea rotundata-based biomass as an adsorbent, employing the Aspen Adsorption software. To this end, a parametric analysis was conducted to evaluate the performance of the bed under different operating conditions, using the Langmuir and Freundlich isotherms in conjunction with Linear Driving Force (LDF) kinetics. Removal efficiencies of up to 92.4% were observed for the Freundlich–LDF model and 92.4% for the Langmuir–LDF model. Additionally, machine learning algorithms were combined with statistical indicators (R², RMSE) to analyze the models’ effectiveness. R² values of up to 0.999 were obtained in the validation and testing phases. This research demonstrates a novel approach to predicting the potential performance of adsorption columns packed with biomass derived from organic waste in the field of engineering, using computational tools with machine learning algorithms. Full article

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21 pages, 2496 KB

Open AccessArticle

Integration of Activated Sludge Kinetics with Microalgae Systems for Carbon Footprint Mitigation in Wastewater Treatment Plants: Case Analysis of the Canary Islands

by Raúl Althay Lorenzo Quijada, Jenifer Vaswani Reboso, Sebastián Ovidio Pérez Báez, Alejandro Ramos Martín and Harue Hernández-Zerpa

Environments 2026, 13(7), 367; https://doi.org/10.3390/environments13070367 - 29 Jun 2026

Abstract

This study presents a comprehensive approach that combines the kinetic characterization of the activated sludge process with the application of microalgae culture systems to reduce direct and indirect greenhouse gas emissions in wastewater treatment plants (WWTPs). Based on experimental data obtained in laboratory [...] Read more.

This study presents a comprehensive approach that combines the kinetic characterization of the activated sludge process with the application of microalgae culture systems to reduce direct and indirect greenhouse gas emissions in wastewater treatment plants (WWTPs). Based on experimental data obtained in laboratory reactors and real operating parameters extracted from a reference plant, the emission routes associated with secondary treatment were analyzed and the mitigation potential by microalgae in the tertiary stage was modeled. Comparative tables, CO₂ capture scenarios and integrated operation diagrams were developed. The results show that the integration of both technologies can significantly reduce BOD residual load, improve energy yield and capture up to 135 kgCO₂/day depending on the remaining substrate. The reduction in aeration demand reached 25%, and BOD removal increased from a range of 72 to 85% (conventional system) to 87–94% (hybrid system). The work supports the engineering plausibility and relevance of a hybrid sludge–microalgae system as an exploratory strategy for WWTP sustainability. Given the experimental design available in the historical laboratory record, the tertiary-stage outcomes are interpreted here as indicative algal–bacterial scenario responses. Because replicate runs under identical conditions and a parallel non-inoculated control reactor were not available, the manuscript does not present these results as definitive tertiary-performance validation. Complementary plant-scale records from the Canary Islands were considered solely as an external plausibility benchmark for the polishing-stage assumptions and were not interpreted as replicate evidence or as a substitute for a non-inoculated control reactor. The specific objective of this work is to derive activated sludge biokinetic parameters from laboratory assays and to use the experimentally constrained residual load framework to assess, at the scenario level, the mitigation potential of a tertiary algal–bacterial stage under Canary Islands conditions. Full article

(This article belongs to the Section Environmental Economics, Energy Systems and Policymaking)

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18 pages, 568 KB

Open AccessReview

Environmental Impacts of In Situ Leaching Uranium Mining: A Review

by Elvira Mussayeva, Meirat Bakhtin and Aliya Kurbanova

Environments 2026, 13(7), 366; https://doi.org/10.3390/environments13070366 - 27 Jun 2026

Abstract

In situ leaching (ISL) is the most popular method for uranium mining worldwide, particularly in arid and semi-arid regions. Despite its economic benefits, ISL raises concerns about radioactive migration and groundwater contamination. This review assesses the environmental impacts of ISL uranium mining, focusing [...] Read more.

In situ leaching (ISL) is the most popular method for uranium mining worldwide, particularly in arid and semi-arid regions. Despite its economic benefits, ISL raises concerns about radioactive migration and groundwater contamination. This review assesses the environmental impacts of ISL uranium mining, focusing on radionuclide transport pathways and key information gaps. This review, focusing on groundwater contamination, radionuclide migration, soil and sediment contamination, atmospheric impacts, vegetation responses, and ecosystem disturbances, summarizes current understanding of the hydrogeochemical, radiological, and environmental impacts of uranium mining. The analysis indicates that groundwater is the environmental component most vulnerable to contamination during ISL operations due to the injection of acidic or alkaline leaching solutions that may mobilize uranium, radium, sulfates, selenium, arsenic, and other potentially hazardous elements. In addition to impacts on groundwater, there have also been reports of soil contamination, airborne dust, radioactive accumulation in flora, and impacts on aquatic and microbiological resources, particularly in arid and semi-arid regions. Although cleanup methods and natural attenuation can minimize contamination to some extent, residual contamination can persist for decades after mine closure. Overall, ISL uranium mining emphasizes the need for effective groundwater management, long-term environmental monitoring, and improved reclamation methods, balancing surface disturbance with long-term hydrogeochemical and environmental concerns. Full article

(This article belongs to the Section Environmental Monitoring and Management)

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18 pages, 9632 KB

Open AccessArticle

Hydrogen Production from Corn Stover Pyrolysis Enhanced by Sewage Sludge Pyrolysis Char-CaO

by Jiatao Dang, Meng Yin, Panbo Yang, Xiaoyu Yan, Kaixin Wang, Manman Wang, Zhixuan Jing, Shuheng Zhao, Xiaotong Chen, Nannan Xie and Jianjun Hu

Environments 2026, 13(7), 365; https://doi.org/10.3390/environments13070365 - 25 Jun 2026

Abstract

Municipal sewage sludge was used to prepare sewage sludge pyrolysis char (SS-PC). The effects of pyrolysis temperature on the morphology and structure of SS-PC were investigated, and the performance of SS-PC-800, prepared at 800 °C, for promoting gas production from corn stover pyrolysis [...] Read more.

Municipal sewage sludge was used to prepare sewage sludge pyrolysis char (SS-PC). The effects of pyrolysis temperature on the morphology and structure of SS-PC were investigated, and the performance of SS-PC-800, prepared at 800 °C, for promoting gas production from corn stover pyrolysis was evaluated in a fixed-bed reactor. The results suggested that adding SS-PC-800 promoted the pyrolysis of corn stover and reduced the activation energy required for thermal decomposition. A further comparison of five metal oxides indicated that CaO had the most pronounced effect on H₂ formation under the tested conditions. A synergistic effect was observed when reactive CaO was introduced into SS-PC. At a pyrolysis temperature of 800 °C, when the mass ratio of CaO to SS-PC-800 was 2:3 and the mass ratio of mixed catalyst to corn stover was 1:5, the H₂ yield was 26.5% higher than that obtained from corn stover pyrolysis alone. In this study, SS-PC was employed as a catalytic material, and the synergistic interaction between its catalytic components and CaO effectively enhanced H₂ production during biomass pyrolysis. These findings can provide a useful reference for the resource utilization of municipal sludge and the development of catalysts for biomass thermochemical conversion. Full article

(This article belongs to the Topic Waste Management for Recycling and Environmental Protection)

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18 pages, 3656 KB

Open AccessArticle

Regurgitated Bird Pellets as Tools to Assess Microplastics in the Environment

by Loris Pietrelli, Patrizia Menegoni, Pietro Giovacchini and Corrado Battisti

Environments 2026, 13(7), 364; https://doi.org/10.3390/environments13070364 - 24 Jun 2026

Abstract

Plastic pollution in terrestrial and freshwater environments and its accumulation along food chains has been poorly studied in birds. In this paper we reported evidence of microplastic (MP) contamination in pellets collected in rural and urban sites for a set of species: common [...] Read more.

Plastic pollution in terrestrial and freshwater environments and its accumulation along food chains has been poorly studied in birds. In this paper we reported evidence of microplastic (MP) contamination in pellets collected in rural and urban sites for a set of species: common kestrel, Falco tinnunculus; great cormorant, Phalacrocorax carbo; barn owl, Tyto alba; little owl, Athene noctua; long-eared owl, Asio otus; Eurasian scops owl, Otus scops; European bee-eater, Merops apiaster; and little egret, Egretta garzetta. A total of 559 pellets were collected and analyzed; among them, 78 microplastics were found on 77 pellets (13.8% compared to the total number of pellets sampled). The following polymers were recorded: polyvinylchloride (PVC), polyethylene (PE), expanded polyester (EPS), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyester (PES), polymethyl acrylate (PMA), rubber, and starch-based biopolymer. We found significantly higher MP frequency in the most anthropized site. Pellets with the highest number of microplastics were those produced by Falco tinnunculus, Asio otus, and Tyto alba, with 30.0%, 29.6%, and 27.1%, respectively. Of a total sample of 78 MP items, 59.0% are represented by fibers, 23.1% by fragments and 17.9% by films. Among the microplastics, fragments of balloons (in a remote area) and biopolymer shopping bags were found. Our results suggest that pellet analysis may represent a cost-effective method for monitoring MP contamination along food chains in terrestrial ecosystems. Full article

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22 pages, 17990 KB

Open AccessReview

Microalgal Systems for Selective Recovery of Lithium, Cobalt and Rare Earth Elements from Waste Streams: A Critical Review

by Alla Silkina, José Ignacio Gayo-Peláez and Kam W. Tang

Environments 2026, 13(7), 363; https://doi.org/10.3390/environments13070363 - 24 Jun 2026

Abstract

The increasing demand for lithium (Li), cobalt (Co), and rare earth elements (REEs) driven by battery technologies, electrification and renewable energy systems has intensified the interest in recovery pathways as an alternative to conventional mining. High-salinity mine waters—including lithium brines, geothermal fluids, and [...] Read more.

The increasing demand for lithium (Li), cobalt (Co), and rare earth elements (REEs) driven by battery technologies, electrification and renewable energy systems has intensified the interest in recovery pathways as an alternative to conventional mining. High-salinity mine waters—including lithium brines, geothermal fluids, and metallurgical effluents—represent both an environmental liability and a significant secondary resource for metal recovery. However, extreme ionic strength, complex metal speciation, and strong competition from major ions severely limit the efficiency and selectivity of traditional extraction technologies. Microalgae and cyanobacteria are promising biological agents for metal recovery via biosorption, bioaccumulation, and extracellular polymeric substance (EPS)-mediated binding, especially in saline and hypersaline systems. This review synthesises current knowledge on microalgal-based recovery of Li, Co, and REEs from high-salinity waters, emphasising co-design principles that integrate strain physiology, their adaptation to the extreme operating conditions, water chemistry, and process engineering. Halotolerant and extremophilic taxa—Nannochloropsis oceanica, Galdieria sulphuraria, and Synechococcus elongatus—are examined as representative models for complementary metal-binding mechanisms and operational niches. Limitations such as weak affinity for lithium, competitive ion suppression, desorption inefficiencies, and scale-up challenges are discussed. Emerging strategies such as modular multi-strain systems, hybrid bio-physicochemical platforms, and biomass valorisation are also addressed. The review concludes that microalgal systems, when co-designed for selectivity and resilience, can contribute to the strategic recovery of critical materials that align with EU, UK and US policies. Full article

(This article belongs to the Special Issue Advanced Technologies for Wastewater Treatment and Resource Recovery)

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30 pages, 3324 KB

Open AccessArticle

Ecological and Health Risk Assessment of Total Petroleum Hydrocarbons and Metals in Water Samples from Bille Mangrove, Niger Delta, Nigeria

by Onyinyechi G. Opara and Vsevolod V. Pavshintsev

Environments 2026, 13(7), 362; https://doi.org/10.3390/environments13070362 - 24 Jun 2026

Abstract

Petroleum exploitation in the Niger Delta has caused widespread contamination of mangrove ecosystems, yet studies that integrate total petroleum hydrocarbons (TPH) and metals in mangrove water are still very limited. This study presents the first dual-pollutant baseline assessment of TPH and five priority [...] Read more.

Petroleum exploitation in the Niger Delta has caused widespread contamination of mangrove ecosystems, yet studies that integrate total petroleum hydrocarbons (TPH) and metals in mangrove water are still very limited. This study presents the first dual-pollutant baseline assessment of TPH and five priority metals (Cd, Cr, Pb, Ni, Zn) in Bille mangrove water, a severely oil-impacted system supporting about 50,000 residents. Water samples were collected from six sites along a contamination gradient (flow station, pipeline passage, old bunkering site) and analyzed for TPH (C8–C40) and metals. All concentrations are reported in mg/L for direct comparability with World Health Organization (WHO) drinking-water guidelines and United States Environmental Protection Agency (USEPA) thresholds. TPH concentrations ranged from 0.18 to 57.66 mg/L, with Site 3 (pipeline passage) showing levels about 320-fold higher than reference sites and exceeding the WHO drinking-water guideline (0.05 mg/L) by up to 1153-fold. Cadmium (0.040–0.350 mg/L) and nickel (0.055–0.561 mg/L) exceeded WHO drinking-water guidelines (Cd 0.003 mg/L; Ni 0.07 mg/L) by 13–117- and up to 8-fold, respectively. Health risk assessment, using USEPA Risk Assessment Guidance for Superfund (RAGS) protocols, revealed a total cancer risk of 4.15 × 10⁻³ at Site 3, 41-fold above the USEPA acceptable threshold of 1 × 10⁻⁴, and extreme non-carcinogenic risk (Hazard Index = 20.03–25.51) at petroleum-infrastructure sites; cadmium contributed 86–88% of both carcinogenic and non-carcinogenic effects. Ecological risk indices classified Site 3 as extreme (Potential Ecological Risk Index = 722, against the Håkanson PERI = 600 “very-high-risk” threshold), mainly driven by cadmium (Er = 310–350) and nickel (Er = 140–150). Source apportionment using the Carbon Preference Index, enrichment factors, and strong TPH–metal correlations (r > 0.88, p < 0.01) clearly identified petroleum operations as the dominant contamination source. This work demonstrates the critical importance of integrated multi-pollutant assessments in petroleum-degraded mangrove water for guiding environmental protection and public-health interventions. Full article

(This article belongs to the Special Issue Toxic and Potentially Toxic Metals and Their Health Risks)

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24 pages, 4817 KB

Open AccessArticle

From Forest to Farmland in the Straight River Watershed: What Has Changed Since 1850?

by Harprabhjot Kaur Dhaliwal, Leslie Ludtke, John Nieber and Joe Magner

Environments 2026, 13(7), 361; https://doi.org/10.3390/environments13070361 - 23 Jun 2026

Abstract

Land-use change from natural vegetation to agricultural systems significantly affects watershed hydrology and water quality. This study assesses the long-term effects of historical land-use change on hydrologic processes and nitrogen transport in the Straight River watershed, Minnesota, USA, using the Soil and Water [...] Read more.

Land-use change from natural vegetation to agricultural systems significantly affects watershed hydrology and water quality. This study assesses the long-term effects of historical land-use change on hydrologic processes and nitrogen transport in the Straight River watershed, Minnesota, USA, using the Soil and Water Assessment Tool Plus (SWAT+) model. Three land-use scenarios were created to assess changes in water balance and nitrate levels. These scenarios represent the reconstructed pre-settlement conditions from 1855, established agricultural development from 2006, and current conditions from 2022. Results show a significant increase in water percolation and groundwater recharge. Percolation more than doubled, increasing from about 118 mm under reconstructed pre-colonial conditions to over 256 mm in 2022. Streamflow increased to 2.1 m³s⁻¹ in 2022, indicating improved hydrologic connectivity and groundwater contributions. Nitrate leaching increased from about 1.14 kg N ha⁻¹ to more than 32 kg N ha⁻¹ (1850s–2022), and nitrate export increased by >2000%, indicating strong nitrate loading. The significant increase in nitrate compared to water fluxes points to agriculture as the primary source of groundwater pollution and downstream nutrient loading. These findings highlight the importance of land-use change in affecting water balance and nutrient behavior. They also point out the need to include a historical baseline in watershed assessments. The results show the importance of better land and nutrient management strategies to reduce nitrate losses and protect water resources in intensively managed agricultural areas. Full article

(This article belongs to the Section Climate Change and Ecosystems)

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34 pages, 4374 KB

Open AccessArticle

Risk-Based Identification and Prioritisation of Plastic Waste Hotspots in Malawi Using a Transferable Decision Framework

by Michael Gormley, Khanda Sharif and Beth A. Cowling

Environments 2026, 13(7), 360; https://doi.org/10.3390/environments13070360 - 23 Jun 2026

Abstract

Plastic waste presents a significant environmental and public health concern in Malawi, where rapid urban growth, limited waste collection services, and informal disposal practices contribute to persistent plastic waste hotspots. In Lilongwe City, the waste collection rate has been reported ranges from 10% [...] Read more.

Plastic waste presents a significant environmental and public health concern in Malawi, where rapid urban growth, limited waste collection services, and informal disposal practices contribute to persistent plastic waste hotspots. In Lilongwe City, the waste collection rate has been reported ranges from 10% to 30%. This means that out of the 500 to 600 tons of municipal solid waste produced each day, only about 50 to 150 tons are collected daily. These hotspots occur in settings such as drains, markets, settlement edges, riverbanks, and lakeshore environments. They intensify health-relevant exposure pathways by encouraging stagnant water, increasing flood risk, facilitating open burning, and supporting the formation of plastisphere biofilms that can contain pathogenic and antimicrobial resistant organisms. This research synthesises evidence on the main sources of plastic waste in Malawi, the mechanisms of leakage across different environments, and the associated health implications. It uses a scoping approach aligned with PRISMA-ScR guidance and is informed by the UK Research and Innovation (UKRI) funded Sustainable Plastic Attitudes to benefit Communities and their Environments (SPACES project), which highlights the influence of behavioural, governance, and environmental factors on plastic pollution. A two phase, risk-based decision framework to support targeted management of plastic waste hotspots is described. Phase 1 focuses on rapid harm reduction through the identification and ranking of hotspots according to risk severity, spatial extent, and feasibility, guiding timely interventions such as drain clearance, waste capture, and temporary stabilisation. Phase 2 addresses longer term prevention by tackling upstream drivers through policy measures, improved services, reuse and reduction schemes, and community engagement. The framework has been developed using evidence from Malawi; however, its methodology could be applied to other low- and middle-income countries that experience similar constraints and exposure pathways. The framework offers a transparent and practical tool for decision makers seeking to allocate limited resources effectively while reducing environmental and health risks associated with plastic waste. Full article

(This article belongs to the Section Environmental Monitoring and Management)

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25 pages, 1873 KB

Open AccessReview

A Review of PFAS Adsorption and Desorption in Saturated Soils: Roles of Mineralogy, Interfacial Chemistry, and Environmental Conditions

by Jay N. Meegoda, Ravisha N. Mudalige, David W. Washington and Duwage C. Perera

Environments 2026, 13(7), 359; https://doi.org/10.3390/environments13070359 - 23 Jun 2026

Abstract

Per- and polyfluoroalkyl substances (PFASs) are persistent environmental contaminants whose mobility in soil and groundwater is strongly controlled by adsorption and desorption processes. In saturated clay-rich soils, these processes are complex because PFASs interact with hydrated mineral surfaces, organic matter, metal oxides, exchangeable [...] Read more.

Per- and polyfluoroalkyl substances (PFASs) are persistent environmental contaminants whose mobility in soil and groundwater is strongly controlled by adsorption and desorption processes. In saturated clay-rich soils, these processes are complex because PFASs interact with hydrated mineral surfaces, organic matter, metal oxides, exchangeable cations, and pore-water constituents. This review synthesizes the current literature on PFAS adsorption and desorption in saturated soils, with an emphasis on clay mineralogy, mineral–water interfaces, pore-water chemistry, and electrochemical double layer (EDL) effects. PFAS retention is influenced by molecular properties such as chain length, functional head group, and charge state, as well as soil properties such as organic carbon content, clay mineral type, surface charge, cation exchange capacity, and Fe/Al oxide content. Longer-chain PFASs and sulfonate-based compounds generally show stronger retention, while shorter-chain PFASs tend to remain more mobile. This review focuses particularly on how an EDL affects PFAS behavior in saturated clay systems. Unlike dry clay surfaces, saturated clay surfaces are covered by structured water, exchangeable ions, and diffuse counterion layers. These hydrated interfacial conditions influence how closely anionic PFASs can approach negatively charged clay surfaces, how dissolved cations reduce electrostatic repulsion or promote cation-mediated binding, and how effectively short-range interactions such as hydrophobic association, van der Waals forces, hydrogen bonding, and surface association contribute to adsorption. Desorption is also emphasized because adsorption does not necessarily represent permanent immobilization. Changes in pH, ionic strength, cation composition, dissolved organic matter, or competing solutes can weaken retention and promote PFAS release. Overall, PFAS mobility in saturated clay-rich soils should be interpreted as a coupled interfacial process rather than simple partitioning to soil solids. Future work should better connect molecular-scale mechanisms, EDL behavior, adsorption–desorption experiments, and saturated transport studies to improve predictions of PFAS retention and long-term groundwater release. Full article

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