Search Results (1,525)

Agroforestry, where trees and shrubs are planted in row-alley systems, can utilize the natural ability of plants to interact with pollutants and serve as a passive biotechnological method for improving air quality. A method for programming air phytoremediation processes is presented, using appropriately shaped plant structures, considering species characteristics and the spatial configuration of plants in row-alley plantings. The main objectives of this study were: to determine the relationship between pollution reduction and the characteristics of plant communities, considering the parameters of individual plants and group characteristics, to determine strategic parameters for the interaction between plants and pollutant flows, and to identify optimization paths for each stage. The optimization of the air phytoremediation process is presented using the example of changes in the fine particulate matter (PM_2.5) concentration pattern, analyzed through numerical experiments using micrometeorological computational fluid dynamics models (ENVI-met software). Ex-ante analysis of hypothetical scenarios showed that introducing appropriate configurations of variable vegetation structure could lead to pollution reductions of up to 19%. The effectiveness of the presented plant systems qualifies this method as a type of bioengineering technology, supporting the multifunctionality of agroforestry systems. Full article

The remediation of large-areas of Cd-contaminated soil, especially agricultural land, remains a major global challenge. Phytoremediation using hyperaccumulators is an effective method for treating Cd-contaminated soils; however, its long-term effectiveness over successive growing seasons has been insufficiently investigated. This study evaluated the sustained phytoremediation capacity of the farmland weed Bidens pilosa L., a known Cd hyperaccumulator, in a three-year pot experiment using contaminated agricultural soil from the Shenyang Zhangshi Irrigation Area (2.08 mg/kg Cd). Two harvest regimes were compared: short-term (harvest at the flowering stage, 70 days) and long-term (harvest at the fruit maturity stage, 108 days). The results showed that although higher total Cd accumulation per harvest was obtained in long-term treatments, short-term experiments resulted in a 14.7% higher net removal rate per day (NR) due to their shorter growth cycle (64.8% of the long-term period). Soil extractable Cd concentrations decreased by an average of 31.2% over three consecutive years of phytoremediation, reducing environmental risk but also limiting subsequent Cd uptake by plants. These findings demonstrate that optimizing harvest timing can substantially improve remediation efficiency per unit of time without the need for soil quality improvement measures. The short growing season characteristic of weeds found in agricultural areas is a practical advantage of phytoremediation. Full article

Hypersaline waters contaminated with crude oil represent a major obstacle for phytoremediation, as few plant species tolerate both high salinity and hydrocarbon toxicity. In this study, the halophyte Halocnemum strobilaceum (Pallas) M. Bieb. was grown hydroponically in hypersaline solutions (50 and 80 g L⁻¹ NaCl) containing crude oil (600 mg L⁻¹). The plant was inoculated with endophytic bacteria isolated in a previous step from its root and selected for salt tolerance and hydrocarbon-degrading potential. The plant behaviour was assessed through growth and photosynthetic performance, while the degradation of hydrocarbons (C < 12 and C > 12) was monitored over time. At 50 g L⁻¹ NaCl, crude oil reduced the plant growth by 60%, but inoculation with endophytic bacteria mitigated this decline, demonstrating their positive influence under combined salt and hydrocarbon stress. At 80 g L⁻¹ NaCl, neither plant biomass nor chlorophyll fluorescence was significantly affected by crude oil, with or without bacterial inoculation, consistent with the strong intrinsic salt tolerance of H. strobilaceum, which likely buffered additional stress inputs. Metagenomic analyses revealed distinct root-associated microbial communities under different treatments, suggesting synergistic plant–microbe interactions that enhanced photosynthetic efficiency and metabolic stability. The presence of endophytes accelerated the degradation of aliphatic hydrocarbons (C10–C40) at both salinity levels. These findings highlight the potential of endophytic bacteria to enhance resilience in H. strobilaceum and its phytoremediation capacity, offering a promising nature-based approach for the sustainable treatment of highly saline, crude oil-contaminated industrial waters. Full article

(1) Research Highlights: This study provides the first integrated assessment of Scots pine (Pinus sylvestris L.) growing in the urban forests of Karaganda, Kazakhstan, a city consistently ranked among the most air-polluted cities globally. We examined the adaptive phyto-chemical response of needles to extreme technogenic stress and evaluated their dual potential as biological filters and renewable sources of bioactive compounds. (2) Background and Objectives: Urban forests are critical for mitigating air pollution; however, the biochemical responses of trees in heavily industrialized environments remain poorly understood. Karaganda faces severe atmospheric pollution from mining, metallurgy, and energy sectors, with particulate matter (PM) levels exceeding permissible limits by up to 20-fold. This study aimed to evaluate the state of Pinus sylvestris, a key component of local protective plantations, by studying heavy metal accumulation, anatomical localization of secondary metabolites, and the phytochemical profile and biological activity of needle extracts obtained using different extraction techniques. (3) Materials and Methods: Needles were collected from 15 trees across three sites in Karaganda’s industrial green zones. Heavy metal content (Pb, Cd, As, and Hg) was determined using atomic absorption spectroscopy and voltammetry. Anatomical–histochemical analysis localizes major metabolite classes. Liquid extracts were prepared using four methods, percolation (PER), vortex-assisted (VAE), microwave-assisted (MAE), and ultrasound-assisted (UAE) extraction, and analyzed by GC-MS. Antimicrobial activity was tested against S. aureus, B. subtilis, E. coli, and C. albicans using the disk diffusion method. The antioxidant capacity (water- and fat-soluble) was measured amperometrically. Statistical analysis was performed using one-way ANOVA with Tukey’s HSD test (p < 0.05). Results: Despite extreme ambient pollution, heavy metal concentrations remained below pharmacopoeial limits (Pb < 0.1, Cd < 0.05, As < 0.01, Hg < 0.001 mg/kg), indicating effective biofiltration without toxic accumulation. Histochemistry confirmed the active synthesis of protective phenolics, flavonoids, and essential oils in the mesophyll, epidermis, and schizogenic cavities. GC-MS identified 72 compounds in the PER extract, 70 (the VAE), 72 in (MAE), and 46 in (UAE). The PER extract exhibited the highest relative abundance of bioactive terpenoids: α-cadinol (5.24%), α-muurolene (4.32%), and caryo-phyllene (2.20%). UAE extracts exhibited elevated 5-hydroxymethylfurfural (6.90%), indicating degradation. Antimicrobial testing revealed that PER produced the largest inhibition zone against S. aureus (15.0 ± 1.0 mm), significantly exceeding that of the other methods (p < 0.001). PER extract also demonstrated the highest water-soluble antioxidant capacity (3600 ± 0.40 mg quercetin equiv./dm³) and substantial fat-soluble activity (1633 ± 0.23 mg gallic acid equiv./dm³). (4) Conclusions: Pinus sylvestris in Karaganda exhibits remarkable adaptive resilience, maintaining safe heavy metal levels while accumulating a rich repertoire of stress-induced secondary metabolites. Classical percolation optimally preserves this native phytocomplex, yielding extracts with superior antimicrobial and antioxidant properties. These findings support a dual-use model wherein urban pine plantations simultaneously serve as living biofilters and renewable sources of standardized bioactive extracts, a concept with direct implications for circular bioeconomy strategies in industrial regions worldwide. This supports the strategic importance of coniferous plantations for bioremediation and sustainable resource use in industrial regions. Full article

It is estimated that at least 16.1% of croplands in China are polluted with heavy metals, and cadmium (Cd) is a typical toxic element inhibiting plant growth. Sorghum bicolor × S. sudanense, a C4 plant with high biomass and stress tolerance, has potential for phytoremediation, but its Cd tolerance mechanism remains unclear. In this study, physiological and transcriptomic responses of Cd-tolerant (S6) and sensitive (2190A/201900131) cultivars were analyzed under 25 mg/L Cd stress. The results showed that S6 exhibited milder phenotypic inhibition (leaf yellowing, growth retardation) than the sensitive cultivar. Cd was mainly accumulated in roots (S6: 4988.37 mg/kg; sensitive: 7030.06 mg/kg at 7 d), with S6 having a lower translocation factor. Physiologically, S6 maintained higher chlorophyll content, stable photosynthetic efficiency (Fv/Fm, PI), and lower malondialdehyde (MDA) accumulation, while antioxidant enzyme (SOD, CAT, APX) genes were significantly upregulated. Transcriptomic analysis identified 47,797 differentially expressed genes (DEGs), enriched in glutathione metabolism, ABC transporter-mediated transport, metal chelation, and antioxidant defense pathways. Genes related to cell wall biosynthesis, metal transporters (ZIP, HMA), and transcription factors (MYB, WRKY) were synergistically upregulated in S6, enhancing Cd sequestration and detoxification. These findings clarify the physiological and molecular mechanisms of Cd tolerance in Sorghum bicolor × S. sudanense, providing a basis for its application in Cd-contaminated soil phytoremediation. Full article

The discharge of untreated paper mill effluent poses significant ecological risks due to its high organic and nutrient loads. This study aimed to assess the phytoremediation potential of Azolla pinnata for treating paper mill effluent. Response Surface Methodology (RSM) and Artificial Neural Network (ANN) modeling approaches were applied and optimization was used for pollutant removal and plant biomass production. Experiments were designed using a Central Composite Design with two independent variables: effluent concentration (0, 50, and 100%) and plant density (10, 20, and 30 g per container). The responses measured were biochemical oxygen demand (BOD), chemical oxygen demand (COD) removal efficiencies, and final biomass yield after 16 days of exposure. RSM produced statistically significant (p < 0.05) second-order regression models for all three responses (coefficient of determination; R² > 0.98), while ANN showed slightly lower prediction errors within the experimental range studied. Maximum observed removal efficiencies were 91.74% for BOD, 80.91% for COD, and 92.66 g biomass yield under 50% effluent concentration and 30 g plant density. Optimization via both models suggested closely comparable operating conditions (79% effluent concentration and 29 g biomass) for optimal performance. The results indicate that A. pinnata demonstrates potential as a low-cost, nature-based treatment system for industrial effluent remediation under controlled conditions. The integration of data-driven optimization with biological treatment contributes to sustainable effluent management strategies by reducing chemical inputs, minimizing energy demand, and enabling biomass generation with potential downstream valorization. Full article

Phytoremediation is a prevalent approach for addressing remediation and production goals in polluted agricultural land. In this study, we examined the impact of four distinct planting ratios on crop growth, accumulation of arsenic (As), and rhizosphere soil dynamics of peanut and maize. The results revealed that intercropping significantly reduced grain As accumulation (42.11–63.16% in maize; 62.28% in peanut under the 1:2 ratio, T2), achieving compliance with Chinese food safety standards (GB 2762-2017, 0.05 mg kg⁻¹). Meanwhile, the T2 treatment exhibited a significantly higher As bioconcentration factor (BCF) and the lowest translocation factor (TF). The metal removal equivalent ratio (MRER) under different planting systems was 1.09, 2.41, 1.07, and 1.46. Additionally, while intercropping did not increase grain biomass per plant, the LER values > 1 for T1 (1.88) and T2 (1.25) demonstrated that complementary resource use enhanced total productivity. Intercropping treatments significantly affected soil properties in both maize and peanut rhizospheres. For maize, intercropping lowered soil pH and available As content but increased dissolved organic carbon (DOC). Notably, only the T1 treatment significantly reduced the cation exchange capacity (CEC) of maize soil. Peanut’s rhizosphere experienced increases in both pH and CEC due to intercropping, with only the T2 treatment yielding a slight rise in DOC. The findings suggest that the maize–peanut intercropping system, especially the T2 system, effectively alters the soil–plant interface to limit As uptake while maintaining productivity, demonstrating its promise for safe utilization of As-contaminated land. Full article

In cold climatic zones, highway transportation routes are significant contributors to sediment-accumulated chloride ions (Cl⁻). Bioswale projects are designed to slow and treat roadway runoff and thereby meter the release of salts, but bioswale function is compromised over time as sediments become saturated with pollutants. This two-year project sought to test innovative practices to improve the function of Illinois Tollway (hereafter, Tollway) bioswales by investigating the effect of biochar addition (20 T/ha) and invasive plant harvesting on: (1) invasive cattail (Typha) dominance, (2) bioswale sediment chloride retention, and (3) harvestable chloride ions associated with living-green Typha tissues across a two-year field study in northeastern Illinois. We found that a single 20 T/ha biochar application resulted in significant increases in Typha [Dry Mass (g/m²) and Stem Count (count/m²), p ≤ 0.05] and sediment chloride concentration (ppm) [p ≤ 0.05]. Harvest did not significantly influence Typha standing stocks (p > 0.05) but did lead to a significant increase in harvestable chloride associated with living-green Typha tissues over the two-year study. This research demonstrates that a single 20 T/ha biochar application coupled with harvest of aboveground Typha biomass is a pathway for scalable management strategies to remove chloride and invasive standing stocks. Full article

Fungal endophytes are microorganisms that inhabit plant tissues without causing disease and emerge as critical mediators of plant stress tolerance, nutrient acquisition, and ecosystem resilience under diverse climate change scenarios. Their unique position within the host allows them to modulate physiological responses more closely than external microbiota. This review explores how endophytic fungi contribute to plant adaptation under climate-induced stresses such as heat, salinity, drought, pollution, and nutrient limitation, with a focus on molecular crosstalk, functional trait modules, and metabolic trade-offs. Key findings emphasize multilayered signaling systems, including MAMP/DAMP recognition, phytohormone regulation, immune tuning, ROS dynamics, and effector deployment, while emerging mechanisms such as cross-kingdom RNA and extracellular vesicle (EV)-mediated exchange are discussed as promising but currently limited in empirical validation within many endophytic systems. Endophytes also enhance nutrient exchange through conditional carbon-for-benefit trade and may shape rhizosphere microbiota and soil activities through plant-mediated inputs. Integrative multi-omics approaches provide predominantly correlational insights into the mechanistic basis of these effects, linking molecular function to ecosystem and community outcomes. These insights have potential applications in climate-resilient agriculture, phytoremediation, and ecosystem restoration; however, their large-scale implementation requires further field-based validation and context-specific assessment. Future priorities should focus on trait-based selection, ecological modeling, and biosafety evaluation to translate microbial functions into reliable field-level strategies that support sustainable crop performance under accelerating environmental stress. Full article

Soil heavy metal contamination poses a major environmental threat, negatively impacting ecosystems, agricultural productivity, and human health. Phytoremediation offers eco-sustainable alternatives to conventional remediation techniques by employing plant species capable of extracting and stabilizing pollutants. This study assesses the potential of Cannabis sativa L. var. ‘Carmagnola’ for the remediation of Pb, Cr, Cu, and Ni from four different growth substrates. This species was selected for its high biomass yield, tolerance to toxic environments, and capacity for heavy metal accumulation. Experimental results showed that the composition of the growing substrate significantly affected HM uptake, with higher accumulation occurring in less compact mixed substrates. HM removal from contaminated growth substrates varied between 55 and 75% for Cr, 60–78% for Ni, 32–86% for Cu and 43–84% for Pb after four months of growth in a greenhouse environment. In addition to pollutant removal efficiency, the study explored thermochemical harvested biomass post-processing via pyrolysis in order to produce biochar, a material with recognized agronomic beneficial properties and positive environmental value. Biochar generated from harvested biomass after phytoremediation tests showed residual HM content lower than the applicable EU thresholds for agricultural soil amendment. Integrating bioremediation with biochar production can promote a circular bioeconomy approach to environmental restoration, by transforming contaminated residual biomass into a useful resource rather than waste. These findings support the feasibility potential of coupling C. sativa phytoremediation and biochar production as an environmentally sustainable strategy for large-scale remediation of heavy metal-contaminated soils. Full article

Cadmium (Cd) pollution has caused severe environmental hazards and human health risks. Phytoremediation, a green and sustainable approach, has emerged as a promising solution for Cd-contaminated soil remediation. Sedum plumbizincicola, a typical Cd hyperaccumulator, can efficiently uptake Cd from soil and translocate it to above-ground tissues, making it an ideal model for studying Cd tolerance mechanisms. Our preliminary studies demonstrated that the Rubber elongation factor (SpREFl) enhances Cd tolerance in S. plumbizincicola, and yeast one-hybrid screening identified SpNAC089 (NCBI accession number: PV553670.1) as a potential upstream transcription factor of SpREFl. In this study, we systematically investigated the regulatory mechanism of the SpNAC089 transcription factor on SpREFl. Subcellular localization assays showed that SpNAC089 is exclusively localized in the cell nucleus, and yeast transcriptional activation experiments confirmed its intrinsic transcriptional autoactivation activity. Transgenic S. alfredii overexpressing SpNAC089 exhibited significantly enhanced cadmium tolerance—with milder leaf yellowing and growth inhibition under Cd stress—and reduced Cd accumulation in roots, stems, and leaves compared to wild-type (WT) plants. Further mechanistic analyses revealed that SpNAC089 directly binds to the 1901–1950 bp region of the SpREFl promoter, which contains cis-acting elements (MBS and TCA motifs). This binding activates SpREFl transcription, thereby upregulating the activities of antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POD) and reducing malondialdehyde (MDA) content under Cd stress, ultimately mitigating oxidative damage. These findings uncover a novel transcriptional regulatory pathway (SpNAC089-SpREFl) underlying Cd tolerance in S. plumbizincicola and highlight SpNAC089 as a candidate gene for optimizing phytoremediation strategies of Cd-polluted soils. Full article

This study aims to elucidate the effects and mechanisms of ammonium (NH₄⁺-N) and nitrate (NO₃⁻-N) nitrogen on the efficiency of Salix linearistipularis K. S. Hao in remediating heavy metal-contaminated soils. Thus, the effects of 15 fertilization treatments (comprising three nitrogen levels and five nitrogen form ratios) on Pb and Cd accumulation, soil properties, microbial structure, and metabolic characteristics were investigated using a pot experiment. The results indicated that Pb and Cd accumulation were the highest under the L12 treatment (60 kg N·hm⁻²·year⁻¹, NH₄⁺-N/NO₃⁻-N = 1:2), whereas nitrate-only treatments, irrespective of concentration, resulted in a decrease in accumulation. In the L12 treatment, biomass increased by 87.0%, with Pb and Cd accumulation rising by 85.71% and 80.0%, respectively, suggesting that biomass may contribute predominantly to heavy metal accumulation. Additionally, NH₄⁺-N/NO₃⁻-N ratio had a greater effect on biomass than the nitrogen application amount. Microbial composition was altered, and the relative abundance of heavy metal-resistant microbes increased. However, the amount of nitrogen fertilizer had a stronger impact on microbial variation. Under different nitrogen application rates and NH₄⁺-N/NO₃⁻-N ratios, the formation or disappearance of unique metabolic pathways related to amino acids and carbohydrates was observed. Furthermore, both microbial metabolism and the bioavailability of Pb and Cd were positively correlated with nitrogen levels and NH₄⁺-N/NO₃⁻-N ratios. These findings indicate a potential association between shifts in microbial metabolism and the bioavailability of heavy metals. Therefore, the simultaneous application of ammonium and nitrate nitrogen in appropriate ratios can enhance the remediation efficiency of S. linearistipularis by boosting biomass and heavy metal bioavailability via microbial metabolism. The findings of this study not only provide novel insights into improving the phytoremediation efficiency of woody plants through fertilization strategies but also lay a theoretical foundation for the effects of nitrogen fertilization on nutrient cycling in metal-contaminated soils. Full article

A 2-acre reedbed system, cultivated with Phragmites australis, was established and utilized to remediate groundwater polluted with chlorinated hydrocarbons at a former industrial site. The reedbed comprised a combination of horizontal and vertical systems over four parallel installations, with a treatment capacity of 305 m³/day. The mean inlet concentration for the four-line treatment was 112.4 mg/L, which was below the specified inlet concentration of 250 mg/L. From 2019 to 2024, the reedbed system effectively eliminated 1,2-Dichloroethane (1,2-DCA), with average removal rates of 97.7%, 98.8%, 98.5%, and 98.6% for Lines 1 to 4, respectively. The average outlet concentrations of 1,2-DCA were 0.70 mg/L, 0.40 mg/L, 0.42 mg/L, and 0.52 mg/L for Lines 1–4, respectively, resulting in an overall average of 0.51 mg/L. We performed the assessment of natural attenuation by first-order decay kinetics for five groundwater monitoring wells, showing values between 0.0012/year and 0.0036/year (shallow wells), 0.0003/year and 0.0021/year (middle wells), and 0.0003/year and 0.0009/year (deep wells). Here, shallow groundwater showed the highest kinetic rates compared to middle and deep groundwater wells. The results indicated that the reedbed system removed the bulk of contaminants through active biological processes involving plants and microbes, and that natural attenuation further degraded 1,2-DCA in the groundwater profiles. Based on data monitoring from 2019 to 2024, the reduction and degradation results showed good removal efficiency for the reedbed systems, combined with natural attenuation in the groundwater. Full article

The wastewater generated during coffee processing contains high levels of acidity and organic matter, posing substantial environmental hazards, particularly in rural areas where traditional treatment methods are financially infeasible. This research assesses the field-scale effectiveness of Chrysopogon zizanioides (vetiver grass) in phytoremediation of coffee wastewater in Huánuco, Peru, with particular attention to how plant maturity affects treatment outcomes. A comparative analysis was performed on untreated and vetiver-filtered effluent from infiltration ponds at four growth stages (6, 8, 19, and 21 months), with measurements of pH, chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), and suspended solids (TSS, SS) conducted according to standardized methods. The findings indicate notable improvements in water quality, as the pH rose from 4.07 ± 0.32 to 5.82 ± 0.40 (p < 0.001) and organic loads decreased by 39–41% (COD: 38,600 ± 12,100 to 23,000 ± 8500 mg L⁻¹ O₂; BOD₅: 27,700 ± 9400 to 16,500 ± 5600 mg L⁻¹ O₂). Total Suspended Solids (TSS) were reduced by 26%, while the settleable suspended solids fraction (SS) decreased by 69%, indicating strong particulate removal through combined filtration and sedimentation mechanisms. Mature vetiver stands (21 months old) showed better results, underscoring the importance of root development for effective phytoremediation. Strong correlations were observed between COD and BOD₅ (r = 0.92), while pH negatively correlated with organic and particulate parameters. The study presents empirical evidence supporting vetiver-based systems as an economical and sustainable approach to decentralized wastewater treatment in coffee-growing areas. Furthermore, it provides actionable insights for improving phytoremediation by focusing on plant maturity, which can be readily adapted for large-scale implementation in resource-constrained settings. The findings underscore the potential of nature-based technologies to address environmental challenges while supporting local economies dependent on coffee production. Full article

This study assesses the environmental performance of three wastewater treatment setups through an attributional, gate-to-gate life cycle assessment (functional unit: 1 m³ of treated wastewater): (Sc1) a traditional municipal wastewater treatment plant, (Sc2) an aquaculture recirculation system using microalgae, and (Sc3) a domestic system combining UASB pretreatment with microalgae polishing. Inventory data were analyzed in SimaPro with ReCiPe 2016 Midpoint (Hierarchist) across seven effect categories. Robustness was tested through sensitivity analyses (±20%) of power consumption and influent characteristics, as well as an additional scenario exploring the offset of methane-recovery electricity. The global warming impact remained consistent across scenarios, ranging from 60.5 to 65.1 kg CO₂-eq·m⁻³, indicating no significant difference within the operational parameters. In most categories, power consumption and influent-related burdens were the main contributors, while the impacts from flocculants and microalgae inoculum were minimal. Sc3 showed a lower freshwater eutrophication potential compared to Sc1 and Sc2 (0.028 vs. approximately 0.049 kg P-eq·m⁻³). Normalization highlighted human carcinogenic toxicity and aquatic ecotoxicity as key impact categories. The methane-offset scenario caused only slight changes at low CH₄ outputs, suggesting that energy recovery depends on context. Full article