Water, Air, & Soil Pollution最新文献

This study investigates the in situ degradation of naphthalene (NAP) in contaminated soil using a biochar-supported nano zero-valent iron (BC@nZVI) composite to activate persulfate (PS). NAP, a persistent polycyclic aromatic hydrocarbon (PAH), poses significant ecological risks due to its carcinogenicity and environmental mobility. The BC@nZVI composite was synthesized via a two-step hydrothermal–carbonization method and characterized using XRD, SEM, TEM, BET, and FT-IR, confirming its enhanced stability and reduced aggregation compared to bare nZVI. Sandbox experiments optimized critical injection parameters, demonstrating that a PS dosage of 2% soil mass and a BC@nZVI:PS mass ratio of 1:2 achieved 76.6% NAP degradation within 4.5 cm of the injection well after 72 h. Pre-injection of BC@nZVI followed by PS at a high flow rate (2.68 L·min⁻¹) enhanced reagent distribution, yielding degradation rates of 44.1–80.3% across a 9 cm radius. Reduced injection volumes (3.2 L) or reversed injection sequences diminished efficiency by 14–25%, while excessive reagents induced radical self-quenching (e.g., SO₄⁻· scavenging) and Fe²⁺ overconsumption. Compared to conventional Fe²⁺-activated systems, the BC@nZVI/PS system exhibited superior soil penetration, sustained radical generation, and reduced PS consumption, effectively addressing challenges in heterogeneous soil remediation. These findings provide actionable strategies for scalable PAH-contaminated site remediation, balancing high efficacy with operational and environmental feasibility.

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The pyrolysis of palm waste offers a sustainable alternative to the open burning of over 1.1 million tons of biomass annually, while simultaneously producing biochar and value-added chemicals. Among these products, fatty acid methyl esters (FAMEs) are particularly attractive as biodiesel precursors derived from the thermal conversion of lipid-containing biomass. In this study, the influence of key operational factors—pyrolysis temperature, feeding rate, and nitrogen atmosphere—was systematically evaluated to optimize FAME and biochar yields. The pyrolytic products were characterized using Thermogravimetric Analysis (TGA), Field Emission Scanning Electron Microscopy (FESEM), and Gas Chromatography–Mass Spectrometry (GC–MS). Thermal analysis showed that the presence of nitrogen enhanced FAME production and improved the thermal stability of biochar, while increasing the temperature decreased FAME formation but promoted aromatic compounds. Morphological observations revealed the development of more crystalline, porous biochar structures at higher temperatures under nitrogen flow. GC–MS analysis indicated that the highest yields of FAMEs and functional biochar were achieved at 450 °C, likely via in-situ methylation of triglycerides facilitated by lignin methoxy groups.

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Burning rice straw as agriculture waste in open fields is a common practice in several Asian countries as part of annual rice cultivation cycle. This process results in a significant emission of air pollutants into the atmosphere. Hence, the aims of this study were: identifying the concentrations of polycyclic aromatic hydrocarbons (PAHs) and benzene, toluene, ethylbenzene, and xylene (BTEX) in gaseous and particulate phases, source identification and health risk assessment of residential living around open burning area in three key agricultural regions of northern Iran (including Mazandaran, Gilan and Golestan) during the summer-fall seasons in 2022. Gaseous-phase samples (PAHs and BTEX) were collected using a SKC pump with XAD-2 and charcoal adsorbent tubes, while particulate-phase PAH samples bound to PMs were captured using a cascade impactor. Air toxics were then analyzed using gas chromatography equipped with flame ionization detector (GC-FID). The results showed that Mazandaran province had the highest concentrations of PMs among all samples at the open burning sites. For particulates PAHs Mazandaran exhibited ∑16 PAHs bounded on PM_10, PM_2.5, TSP of 3495.1 ± 274 ng/m³, 3478.1 ± 329.75 ng/m³ and 4150 ± 310 ng/m³ at open burning respectively. For gaseous samples from non and open burning areas, the concentration of ∑16 PAHs in Mazandaran province were 4.3 ± 0.74 ng/m³ and 2718 ± 57.3 ng/m³, respectively. The concentrations of total BTEX in Mazandaran during the rice straw open burning phenomenon, were 802.58 ± 75.55 μg/m³. To assess the health risks, incremental lifetime cancer risk (ILCR) was calculated for PAHs; and lifetime cancer risk (LTCR) and hazard quotient (HQ) of BTEX in children and adult were determined. Calculated ILCR for adult and children in Mazandaran were 2.32E-04 and 1.62E-05 which were unacceptable compared to U.S. EPA limits of 1.0 E-06. For BTEX, LTCR value exceeded the acceptable threshold and the HI in child of Mazandaran was determined more than 1. There is limited field research in the world and no study conducted in Iran about human health risk of rice straw open burning. Our results revealed that the highest values of ILCR and LTCR allocated to the open burning phenomenon in Mazandaran; moreover, the source diagnosis ratio illustrate the correlation to rice straw open burning emissions.

In this study, zinc (Zn), copper (Cu), and iron (Fe) nanoparticles (NPs) were prepared by green synthesis method as an environmentally friendly method using Arizona cypress leaf extract and nitrate solutions of Zn, Cu, and Fe. FESEM and BET analysis showed that the smallest size (32.26 nm) and the highest specific surface area (147.66 m²g⁻¹) were observed for the synthesized Cu-NPs. The NPs at two rates of 0.5 and 1% of soil dry weight were added to a soil contaminated with 100 mgkg⁻¹ of each Zn, nickel (Ni), lead (Pb), and cadmium (Cd). The effects of syntesized NPs on the uptake of HMs were invesigated in the presence of quinoa as a plant with a high capacity to accumulate HMs. According to the results, the most significant decrease in the uptakes of HMs by quinoa compared to the control was observed after the application of the Cu-NPs (1%). The lowest metal uptakes were found for Ni in shoot and Pb in root (19.06 and 20.82 μgpot⁻¹, respectively). EDTA extractable Zn, Ni, Pb, and Cd in post-harvest soils were the lowest under the influence of Cu-NPs (1%) (44.12, 25.05, 42.8, and 44.5 mgkg⁻¹, respectively). The highest uptakes of all four HMs by the plant were observed after the application of the Fe-NPs (0.5%) with the lowest specific surface area (11.42 m²g⁻¹). The findings of this study showed that the synthesized Cu-NPs had the highest immobilization capacity of HMs compared to other tested NPs, which was most probably due to having the highest specific surface area and the smallest particle size. High efficiency, environmental friendliness, and low cost of preparing the green metal-NPs have made them a recommended solution for removing HMs from polluted soils.

This study characterizes rare earth element (REE) distributions in Afram Plain soil profiles using neutron activation analysis (NAA) combined with Bayesian Hierarchical Models (BHMs). Forty-eight samples from eight locations across seven soil types were analysed at the Ghana Research Reactor-1 using k₀-standardization. Mean total REE concentration was 728.6 mg/kg, substantially higher than regional comparisons, with an unusual HREE-enriched signature (ΣLREE/ΣHREE ≈ 0.6). Waterbody sediments showed highest accumulation (763.8 mg/kg), while Haplic Lixisols had highest La concentrations (64.10 mg/kg). The BHM identified depth and pH as the most clearly influential predictors of total REE concentrations, with REEs increasing with depth and accumulating preferentially under higher pH conditions. Soil-type effects, while allowing for group-level variability, showed 95% highest density intervals spanning zero for all soil types, indicating that distinguishing these effects requires larger sample sizes. Enrichment factors for HREEs (Tm, Yb, Lu) reached extremely high values (10²–10³), warranting careful interpretation given potential normalization artifacts from variable iron content. Fractionation indices revealed persistent negative Ce anomalies and neutral to positive Eu anomalies across profiles. This study demonstrates the utility of combining NAA with BHM for transparent uncertainty quantification in environmental REE assessments, while acknowledging that mineralogical characterization is needed to explain the unusual HREE enrichment patterns.

Organic/inorganic separation pretreatment of sewage sludge (SS) can enrich carbon resources in SS into organic sludge (OS), thereby facilitating the preparation of activated carbon (AC). Herein, three composite ACs were synthesized by co-pyrolysis of OS with reed, wheat straw, or sawdust, respectively, to systematically investigate their synergistic effects on structural and adsorption properties. The results revealed that AC prepared with a 7:3 mass ratio of OS to reeds at 700℃ exhibited the highest specific surface area of 363.0 m²/g, significantly outperforming the other two composite ACs. The surface morphology and distribution of oxygen-containing functional groups of the composite ACs were distinctly influenced by the inherent characteristics of the biomass used. Batch experiments demonstrated that the AC composite synthesized from OS and reed at a mass ratio of 7:3 exhibited the optimal adsorption capacity, with values of 11.7 mg/g for Pb²⁺ and 10.6 mg/g for Cd²⁺, both of which were superior to those of AC prepared solely from OS. Kinetic and isothermal analyses revealed that the adsorption processes of Pb²⁺ and Cd²⁺ onto the composite ACs were best described by the pseudo-first-order kinetic model and Langmuir isotherm model, respectively. Mechanistic investigations indicated that the adsorption mechanism primarily involved three synergistic processes: pore filling, complexation, and electrostatic attraction. This study provides a green strategy for the high-value utilization of OS and biomass, while offering an efficient adsorbent for heavy metal-contaminated wastewater treatment.

Composted sewage sludge (CSS) is a nutrient-rich organic amendment with the potential to replace or supplement chemical fertilizers (CFs) by recycling nutrients. However, its effects on grain yield and nutritional quality are still not fully understood. This study evaluated the effects of partially or entirely replacing CFs with CSS on rice growth, yield, grain quality, and soil fertility over three crop seasons. The experiment cultivated Oryza sativa L. cv. Bekoaoba (2022 and 2024) and Fukuhibiki (2023) and tested three treatments: CF alone (control), a 50:50 mix of CSS and CFs (CSS + CF), and CSS alone. Across the three seasons, average results showed that the CSS treatment significantly reduced both grain yield and protein content compared to the control. Specifically, grain yield decreased by 25%, and protein content declined by 28% relative to the control (8 t/ha and 8.3%, respectively; p < 0.05). However, the CSS + CF treatment resulted in smaller reductions in grain yield (12.5%) and protein content (7%) compared to the control (p > 0.05). In terms of soil quality, the CSS treatment significantly improved soil organic matter by 24% and phosphorus by 20% compared to the control (p < 0.05). Overall, this study underscores the potential of CSS as a low-cost and sustainable alternative to CFs with long-term benefits for soil health, while emphasizing the need for careful monitoring of heavy metal accumulation. These findings provide valuable insights for advancing sustainable fertilization practices and promoting nutrient recycling from sewage sludge within a circular economy framework.

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Terrestrial ecosystems act as significant reservoirs for human and veterinary antibiotics. Given that the underlying mechanisms can be generalized to the broader group of amphoteric antibiotics, ciprofloxacin (CIPRO) (the most prescribed fluoroquinolone) and hematite and goethite (primary oxides of soils developed in the humid tropics) were selected. We have sought to integrate the information available in the literature on the fundamental characteristics (mainly the charge dynamics as a function of pH variations) of CIRO and Fe oxides and, thorough critical analysis and proposing the formation of a most stable double covalent bound, to elucidate the chemical principles governing both outer- and inner-sphere adsorptions of CIPRO on Fe oxides. As the pH rises above 4.1, the zwitterionic species of ciprofloxacin (CIPRO ±) increasingly predominates, enabling outer-sphere adsorption through the interaction of its negatively charged groups with the positively charged adsorption sites on Fe oxides. Considering the combination of dominant pH in soils (4–6) and the possibility of surface charges on Fe oxides and CIPRO, the following inner-sphere adsorption dynamics are expected: i) more acidic condition (pH ~ 4.0) – easer rupture of the FeO–H^−0.5 than that FeO–H₂^+0.5, CIPRO(NH₂⁺)-ferrol bond (FeOH-NH₂CIPRO and FeO-NH₂CIPRO monodentate complex formation) and H⁺ release; ii) less acid condition (pH ~ 6.0) – easer rupture of the Fe–OH₂^+0.5 than that Fe–OH^−0.5, CIPRO(COO⁻)-ferrol bond (Fe-COOCIPRO monodentate complex formation) and H₂O or OH⁻ release; iii) combination of inner-sphere adsorption by NH₂⁺ and COO⁻ groups and closing of the Fe-COO(CIPRO)NH₂-OHFe ring structure (bidentate complex formation). This wide range of charges and bond stability conditions ensure low CIPRO potential of groundwater contamination in highly weathered tropical soils.

Microplastic (MP) pollution has become a widespread and complicated threat to marine ecosystems, causing major problems for both the environment and the community. This review puts together and analyzes published literature between 1966 and 2025. In this review, an extensive analysis was conducted to explore notable progressions on microplastics inside marine ecosystems, encompassing diverse aspects. Their formation through weathering and degradation mechanisms were reviewed. This review emphasized the long-lasting nature of microplastics in marine ecosystems. An in-depth review of the detrimental consequences of microplastics on marine ecosystems was highlighted, spanning the physical damage inflicted upon species, the effects resulting from ingestion, and their function as transporters for pollutants. We examined the needed regulatory environment and comprehensive policy-frameworks to effectively tackle this widespread global issue. Additionally, the contribution of microorganisms in the degradation of microplastics, providing valuable knowledge on potential strategies for bioremediation and the underlying microbiological mechanisms was studied. This analysis highlights the complex biological interdependencies and subsequent consequences within marine food chains, thus emphasizing the urgent need for proactive measures. This review takes a new approach by using Artificial Intelligence (AI) as a helpful tool for finding MP, modeling it, and improving the efficiency of microbial degradation. We look at how AI-assisted spectroscopy, machine learning models, and autonomous surveillance technologies can help make real-time remediation systems. This review connects environmental microbiology, toxicology, and data science to create a transdisciplinary roadmap for dealing with marine microplastic pollution. It also suggests flexible plans for future biotechnological and regulatory actions.

Fenton Iron Sludge (FIS) was used to enhance the anaerobic digestion performance of actual papermaking wastewater (PW), and the impact of FIS on the physicochemical properties of granular sludge was elucidated in this study. The experiment results indicated the addition of FIS increased the soluble chemical oxygen demand (SCOD) removal efficiency by 11.77% and the methane production by 15.13% under high organic load. The concentration of electrochemically active substances in the extracellular polymeric substances (EPS) was increased by adding FIS. Loosely bound extracellular polymeric substances (LB-EPS) and tightly bound extracellular polymeric substances (TB-EPS) in the experimental group exhibited 1.15 and 1.17 times increases in electron transport capabilities compared to the control group. In the hydrolysis experiment, the protein removal efficiency increased by 10.5%, and in the acidification experiment, the concentration of acetic acid increased by 37.7%. This indicated that FIS significantly promoted the hydrolysis and acidification process of anaerobic digestion, thereby enhancing the anaerobic digestion performance of the actual PW.