Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering最新文献

Polyethylene nanoplastics (PE-NPs) are emerging wastewater contaminants that may disrupt biological phosphorus removal (BPR). To assess their effects on BPR, experiments with PE-NPs at 0-20 mg/L were conducted. With increasing PE-NPs, phosphorus removal declined from 96.16% to 83.97% and effluent COD increased from approximately 20-43.04 mg/L. At 20 mg/L PE-NPs, anaerobic PHA synthesis and aerobic PHA consumption were measured at 83.19% and 82.74% of the control values, respectively. Total EPS dropped from 136.78 to 118.26 mg/g MLVSS alongside a minor increase in the PN/PS ratio, and intracellular ROS levels reached about 128% of those in the control. Fluorescence excitation-emission matrix and Fourier-transform infrared spectroscopy analyses indicated a reduction in aromatic protein and microbial by-product signals, alterations in N-H/O-H and amide-I hydrogen bonding environments, and a shift in EPS protein conformation from α-helix to β-sheet/aggregate-rich structures. High-throughput sequencing revealed a microbial community shift, marked by a decrease in phosphorus-accumulating organisms (PAOs, e.g., Acinetobacter and Candidatus Accumulibacter) and an increase in glycogen-accumulating organisms (GAOs, notably Candidatus Competibacter). This shift intensified carbon competition, limiting PAOs energy storage and phosphate uptake. These combined effects-oxidative stress, altered EPS, and microbial shift-decouple carbon-phosphorus metabolism, accelerating BPR deterioration.

Clopyralid is among the most widely used herbicides worldwide. Discharging clopyralid-contaminated water into the environment can adversely affect human health and ecosystems. Research on the biological treatment of clopyralid-laden wastewater is crucial for enhancing process performance and preventing environmental contamination. This study investigates the biodegradation of clopyralid by an activated sludge (AS) culture to clarify its microbial degradation and inhibition kinetics. Furthermore, the inhibitory effect of clopyralid on isolated AS microorganisms (bacteria and fungi) was examined using paper disk and broth culture methods. The results demonstrate the potential of AS to biodegrade clopyralid. Clopyralid degradation rates increased with increasing herbicide concentration from 50 to 225 mg/L, then declined. At 300 mg/L, clopyralid biodegradation was completely inhibited. Luong's kinetics model for inhibitory substrates accurately described this biodegradation pattern. All cultured bacteria and fungi were inhibited at higher clopyralid doses. However, while most bacteria were inhibited at 1200 mg/L of clopyralid, fungi were inhibited at a 10-fold higher concentration. At this concentration range, clopyralid exhibited a bacteriostatic/fungistatic effect rather than a bactericidal/fungicidal one. That is, it did not cause lethal disruption of essential cellular functions. The findings of this study could inform strategies to enhance clopyralid biodegradation at high concentrations in AS reactors.

The presence of polycyclic aromatic hydrocarbons (PAHs) in ambient air is mainly linked to anthropogenic activities, particularly fossil fuel use and residential wood combustion, posing risks to human health. This study evaluated atmospheric PAHs in Temuco, Chile, characterized their spatial and seasonal distribution, and investigated the in vitro effects of environmentally relevant PAH mixtures on human bronchial epithelial cells (BEAS-2B). Passive air samplers equipped with polyurethane foam (PUF) disks were deployed at two urban sites (Universidad Católica de Temuco and Padre Las Casas) and one rural site (Maquehue sector). Sampling covered summer and fall-early winter, with seasonal assessment conducted in Padre Las Casas. PAHs were quantified by gas chromatography-mass spectrometry (GC-MS), and cell viability was assessed using the MTS assay after exposure to defined PAH mixtures. Spatial variability was observed, with phenanthrene, fluoranthene, and pyrene predominating in urban areas and increasing during winter, while dibenzo(a,h)anthracene was detected exclusively in the rural sector. In BEAS-2B cells, PAH exposure caused a dose and time-dependent reduction in viability, reaching significance at 20 and 28 µM after 48 and 72 h. These findings highlight PAH persistence and potential adverse effects on respiratory epithelial cells, underscoring the need to reduce population exposure.

Biochar is a promising, sustainable adsorbent for hydrogen sulfide (H₂S) removal, yet its adsorption capacity is governed by complex interactions among material properties, preparation conditions, and operating parameters. In this study, we develop and systematically compare a suite of machine learning (ML) models including Decision Tree, Random Forest, AdaBoost, K-Nearest Neighbors (KNN), Convolutional Neural Network (CNN), Support Vector Regression (SVR), and an Ensemble Learning scheme to predict the H₂S adsorption capacity of biochar. The models are trained on 277 experimental data points collected from the literature, using a comprehensive set of inputs that includes physicochemical properties (specific surface area, mass percentages of C, O, and N, C/N, O/N, (O + N)/C, total pore volume, and average pore diameter), pyrolysis conditions (temperature and time), and reaction conditions (gas humidity, adsorption temperature, H₂S concentration, gas flow rate, and breakthrough time). Model robustness is ensured through 5-fold cross-validation and rigorous outlier assessment using the Leverage (Williams) method, while SHapley Additive exPlanations (SHAP) are applied to interpret feature contributions. Among all algorithms, KNN emerges as the best-performing model, achieving the highest coefficient of determination (R² ≈ 0.94) and the lowest mean squared error and average absolute relative error on the full dataset. Sensitivity and SHAP analyses consistently identify breakthrough time as the dominant factor controlling adsorption capacity, followed by specific surface area, gas humidity, and oxygen-to-nitrogen ratio. These findings demonstrate that combining diverse ML architectures with robust statistical validation provides an accurate, interpretable, and computationally efficient alternative to conventional experimental determination of H₂S adsorption capacity, facilitating rapid screening and optimization of biochar-based gas purification systems.

The aim of this study was to evaluate the survival, metabolism and swimming behavior of Rhinella arenarum tadpoles exposed to burned sediments from dry lagoons located in the "Los Sapos" Island (Santa Fe Province, Argentina), with different fire events over one year: no fire events (NF), two fire events (TF) and multiple fire events (MF). The physicochemical parameters of the sediments were analyzed. A sediment test was performed using 25, 50 and 100% dilutions of each sediment sample at a microcosm scale for 48 h. Tadpole survival and swimming behavior, as well as acetylcholinesterase (AChE) and glutathione S-Transferase (GST) activities (markers of neurotoxicity and oxidative stress), were analyzed. The burned sediments showed high conductivity (<1000 μS/cm2) and proton activity with presence of carbonates. The treatments with sediments from TF and MF led to mass tadpole mortality (100%). Diluted 25 and 50%, these treatments also resulted in a significant decrease (30%) in the activities of AChE and GST as well as in the swimming speed (60%) and total distance moved (40%) respect to the NF treatment (ANOVA and Tukey's test, p < 0.05). These results highlight the high ecological risks faced by tadpole reproductive sites that have been affected by fires.

Core-shell Fe₃O₄@poly(acrylic acid)/chitosan (Fe₃O₄@PAA/CS) submicrospheres were synthesized through the polymerization of acrylic acid in CS solution, using uniformly sized magnetite colloid nanocrystal clusters (MCNCs) as the core materials. The obtained submicrospheres were characterized using scanning electron microscopy, transmission electron microscopy, dynamic light scattering, Fourier-transform infrared, thermo-gravimetric, vibrating sample magnetometer, and X-ray diffraction analyses. The results confirmed that the submicrospheres with the Fe₃O₄ nano-core located in the central region and encapsulated by a CS shell exhibited superparamagnetic behavior. The removal efficiency of Congo red (CR) dye by magnetic submicrospheres was determined by investigating several factors, including pH, adsorbent dose, contact time, and dye concentrations. Over 97.4% of CR (90 mg L^-1) was removed at a dosage above 1.2 g L^-1. The maximum adsorption capacity obtained from the Langmuir isotherm model for CR was 143 mg g^-1 at 290 K. Adsorption kinetics and isotherm data were well described by the pseudo‑second‑order and Langmuir models, respectively. Furthermore, the submicrospheres were successfully regenerated and, subsequently, reused for four adsorption-desorption cycles without any noticeable loss of stability. The exceptional removal performance of magnetic submicrospheres on CR renders it a highly appealing adsorbent for the treatment of dye-containing wastewaters.

Heavy metal pollution in aquatic ecosystems demands sustainable, scalable remediation solutions. This study evaluated the long-term (three-month) phytofiltration potential of the aquatic moss Taxiphyllum barbieri (Cardot & Copp.) Z. Iwats, under controlled multi-metal exposure and in real cement factory effluent (CE). In simulated solutions, the moss achieved high removal efficiencies (>93%), particularly for Ni (99.2%) and Zn (99.1%), with substantial tissue accumulation (e.g., Cu: 221.86 mg kg^-1, Cd: 210.36 mg kg^-1). In cement effluent, removal efficiencies were lower (41-64%), yet bioconcentration factors (BCFs) increased dramatically, reaching 4523.9 for Zn and 4093.8 for Cd, indicating efficient hyper-concentration of bioavailable metal fractions. Physiological assessments revealed metal-specific stress responses, including antioxidant activation, significant proline accumulation (up to 328% under Ni), and modulated pigment profiles. Notably, exposure to CE stimulated moss growth (+23.37% RGR) and enhanced photosynthetic pigments, demonstrating physiological resilience under realistic, low-level mixed-metal stress. These findings confirm T. barbieri as a robust, adaptable phytoremediation agent capable of high metal removal and bioconcentration while maintaining physiological integrity. The results support its potential integration into engineered, low-energy wastewater treatment systems for sustainable mitigation of heavy metal contamination.

This study analyses the long-term variations in air quality at Amity University, Noida, Uttar Pradesh, India, from May 2017 to December 2024, focusing on the monthly mean Air Quality Index (AQI) and its key precursors. The specific objectives of the study are to: (i) characterize temporal trends in AQI; (ii) identify dominant pollutant drivers influencing seasonal air quality; and (iii) evaluate the relative contributions of anthropogenic and meteorological factors to observed variations. The average AQI during the period was 217, with peaks in winter due to temperature inversions and increased emissions, and improvements during monsoon months due to wet deposition. The highest AQI (487) was recorded in November 2017, while the lowest (40) was observed in July 2024. A notable reduction in AQI occurred during the COVID-19 lockdown in 2020, highlighting the impact of reduced anthropogenic activities. Particulate matter (PM_2.5 and PM₁₀) emerged as the primary contributor to high AQI, frequently exceeding the National Ambient Air Quality Standards (NAAQS) during winter. Nitrogen dioxide (NO₂) peaked in June 2023 (192 µg m^-³), while ammonia (NH₃) exhibited episodic spikes, mainly due to agricultural activities. Ground-level ozone (O₃) levels fluctuated, indicating variations in precursor emissions and photochemical processes. Correlation analysis revealed a strong relationship between AQI and PM_2.5 (r = 0.9) as well as PM₁₀ (r = 1.0), emphasizing particulate pollution as the dominant driver of poor air quality. Unlike studies that focus primarily on PM_2.5 and PM₁₀, this research gives equal attention to secondary pollutants and their role in shaping AQI trends. Local meteorological conditions play a critical role, and the associated emission sources were also examined to provide a comprehensive understanding of pollutant variability. The findings conclude that PM remains the most influential factor governing air quality in the region, and sustained improvement will require targeted emission control strategies addressing both primary particle sources and secondary pollutant formation pathways.

Environmental pollution caused by industrial activities, vehicle emissions, and improper waste disposal poses serious risks to human health and the ecosystem. This study investigates the adsorption of m-toluidine (m-T) using activated carbon derived from Balanites aegyptiaca seeds (BASC) via H₃PO₄ chemical activation. The BASC was characterized using scanning electron microscopy and Fourier transform infrared spectroscopy and analyzed for its moisture, ash, volatile matter, and carbon content. The material exhibited a high surface area of 675.0 m² g^-1, an iodine number of 581 mg g^-1, and a point of zero charge (pH_pzc) of 4.42. Batch adsorption experiments were performed to assess the effects of pH, contact time, and temperature. Results showed that adsorption efficiency increased with temperature. The adsorption behavior is favorable and followed the Temkin isotherm, pseudo-second-order kinetic model, and a three-step intraparticle diffusion mechanism. Thermodynamic analysis revealed that the adsorption process was endothermic, spontaneous, and associated with increased system entropy. These results underscore the potential of adsorption as an efficient wastewater treatment approach for eliminating organic contaminants such as m-T from actual aqueous environments.

Excessive water use in residential buildings often arises from design deficiencies and conventional sanitary installations, which hinder the adoption of integrated conservation strategies. This study evaluates a package of efficient technologies to optimize water use in a 10-story multifamily building in Cusco, Peru, combining graywater reuse,rainwater harvesting, dual-flush toilets, flow-regulating fixtures, and smart leak detection. A quantitative, non-experimental, cross-sectional, and descriptive design was applied over a 6-month period from October 2024 to March 2025, comparing baseline operation with the proposed efficient configuration. The results show that the combined system reduces both potable water demand and household expenditure, with average monthly water consumption and billing decreasing by approximately 22% and 41%, respectively, while more than 200 cubic meters of gray and rainwater were recovered for non-potable uses such as toilet flushing, washing, cleaning, and irrigation. The novelty of this work lies in the integrated assessment of multiple low-cost technologies under real operating conditions in a Latin American multifamily building, linking detailed consumption records with tariff structures and leak scenarios. These findings indicate that efficient technologies can significantly improve urban water management, support climate and resource policies and contribute directly to several United Nations Sustainable Development Goals, particularly SDG 6 (Clean Water and Sanitation), SDG 9 (Industry, Innovation and Infrastructure), SDG 11 (Sustainable Cities and Communities), SDG 12 (Responsible Consumption and Production) and SDG 13 (Climate Action).