International Journal of Phytoremediation最新文献

Petroleum hydrocarbon contamination poses a major environmental challenge, necessitating sustainable bioremediation approaches. The present study aimed to evaluate the bioremediation potential of indigenous bacterial isolates from oil-contaminated soils and their synergistic effects with plants. Nineteen bacterial isolates were screened, among which Bacillus lentus (M8) and Paenibacillus curdlanolyticus (M9) exhibited superior hydrocarbon-degrading capabilities. In phytoremediation trials, microbial inoculation (M8/M9) restored wheat growth to 85% of controls in 5% oil-contaminated soil (OCS), though 10% OCS remained inhibitory (40% growth reduction). High performance liquid chromatography (HPLC) revealed extensive hydrocarbon transformation by M9 + maize, with new peaks (2.5-6.5 min) indicating metabolic activity, while gravimetry confirmed 86% degradation of 5% OCS by M9 + wheat at 60 days, surpassing bacteria-only treatments (60-67%). Overall, the results reveal that Bacillus-plant consortia effectively accelerate petroleum hydrocarbon degradation and promote soil recovery, offering a practical and eco-friendly solution for environmental restoration.

Poplar trees possess dual functionality for soil heavy metal phytoremediation and cicada cultivation. However, the health risks associated with metal transfer along the soil-root-cicada pathway require further elucidation. Inductively coupled plasma optical emission spectrometry analysis of soil (n = 36), poplar root (n = 9), and cicada life stage (n = 27) samples revealed distinct heavy metal distribution patterns. Soil concentrations (mg·kg^-1) ranged as follows: Cd 0.03-5.67, Pb 2.50-433, Cu 11.25-37.73, Ni 27.00-65.50, Zn 58.33-141.50. Metal partitioning showed Cd (0.16-33.05 mg·kg^-1) and Cu accumulating in adult cicadas, while Zn (peak 609 mg·kg^-1), Pb (0.30-94.33 mg·kg^-1) and Ni were predominantly retained in exuviae. Notably, Zn exhibited particularly strong bioaccumulation from roots. Cd and Pb concentrations in edible cicada stages and Cd in exuviae exceeded safety limits, correlating with substantial root accumulation (Cd: 0.75-19.67, Pb: 4.32-85.33 mg·kg^-1). Risk assessment showed negligible non-carcinogenic risks (HQs < 1.0) at typical consumption rates, though adults presented higher Cd-related risks than nymphs. Soil Cd safety thresholds were established at 1.52 mg·kg^-1 (adults) and 3.97 mg·kg^-1 (nymphs). These findings demonstrate significant trophic transfer amplification of metal risks and provide crucial safety benchmarks for sustainable cicada production.

Water pollution from textile industries poses severe ecological risks due to the presence of toxic dyes, heavy metals, and persistent organic pollutants. This study evaluates the phytoremediation potential of Urtica dioica (stinging nettle), a locally abundant species in Himachal Pradesh, for treating textile wastewater using a coconut-coir-based hydroponic system. Untreated effluent from India textile industry, was subjected to a 40-day treatment under controlled conditions, followed by physicochemical and biological analyses in accordance with American Public Health Association (APHA) and Indian standards (IS). The system achieved substantial reductions in cadmium (84.62%), zinc (92.31%), lead (93.33%), Biochemical oxygen demand (BOD 89.32%), Chemical oxygen demand (COD 79.2%), phenolic compounds (81.81%), and ammonical nitrogen (98.36%), alongside notable improvements in water clarity, color, and odor. Post-harvest biomass management through pyrolysis or phytomining supports circular economy applications and safe disposal. Compared to conventional methods, this hydroponic phytoremediation approach is cost-effective, energy-efficient, and produces minimal sludge or hazardous by-products. The findings highlight the potential of hydroponically cultivated Urtica dioica as a scalable, low-cost, and sustainable solution for decentralized wastewater treatment, advancing green engineering practices.

Soil contamination with cadmium (Cd) along with drought stress causes severe decline in wheat production around the world. The current study was designed to unravel the role of Zn in modulation of Cd phytotoxicity and phytoremediation in wheat under drought stress. Wheat plants were exposed to Cd (0, 20 mg kg^-1) and Zn (0, 10 mg kg^-1) under moist (70% of water-holding capacity and drought stress (35% of water-holding capacity) conditions. A significant reduction was observed in plant growth (44%), chlorophyll contents (47%), and stomatal conductance (46%) in plants under the dual stress of Cd and drought. The level of oxidative stress markers (H₂O₂ and lipid peroxidation) enhanced under combined Cd and drought stress, resulting in membrane damage. The supplementation of Zn partially alleviated negative effects of Cd and drought on plants. Under the combined treatment of Cd and drought, Zn addition caused a 27%, 24%, and 27% increase in plant growth, chlorophyll contents and stomatal conductance, respectively. Zinc application limited root to shoot transfer of Cd and lowered the oxidative damage by enhancing the activities of catalase, superoxide dismutase, and peroxidase by 16%, 18%, and 17%, respectively. Hence, the exogenous application of Zn proved to be a promising strategy for mitigating the phytotoxicity of Cd and enhancing its phytostabilization under water limited conditions.

Vegetation mitigates air pollution with trace elements (TEs), by capturing them on plant surfaces. However, retention on foliage is typically temporal and TE can be washed off by precipitation. Due to the inherent variability and unpredictability of natural rainfall, as well as complex environmental factors, pollutant removal via precipitation is often studied using simulated rain. This study aimed to determine whether simulated rainfall can reliably replace natural rainfall in experiments assessing the wash-off of TEs from leaf surfaces. Plant material was foliage of 17 plant species (herbaceous plants, deciduous and evergreen trees, and shrubs), growing in an urban park in Wuhan, China. Across all examined TEs (Mn, Fe, Cu, Zn, As, Ba, Pt), simulated rainfall generally removed a higher fraction of pollutants than natural rainfall. Interestingly, natural rainfall was associated with increased amounts of Cu and Zn on foliage after precipitation. Pollutant removal efficiency varied depending on the type of rainfall and plant groups, with natural rainfall being more effective in TEs removal from evergreen trees, while simulated rainfall performed better with deciduous shrubs and herbaceous species. These inter- and intra-group variations suggest that simulated rainfall does not fully replicate the mechanisms of pollution removal occurring in real-life conditions.

Soil pollution caused by heavy metals (HMs) has become a major global concern, particularly due to the risks associated with their accumulation in the food chain. Phytoremediation has gained recognition as an economical and sustainable technique for addressing HM pollution. Phytoremediation leverages the ability of plants to absorb, break, or stabilize contaminants. Further, a novel technology called nano-phytoremediation has emerged to enhance phytoremediation's efficacy. Zinc oxide nanoparticles (ZnPs) are widely used in nano-phytoremediation because of neutral pH, chemical stability, and affordability. This review aims to consolidate current knowledge on the application of ZnPs to enhance phytoremediation, with an emphasis on elucidating their underlying mechanisms of action. A bibliometric analysis is presented to emphasize the increasing research focus on ZnPs in phytoremediation. The application of ZnPs in phytoremediation is extensively examined. The review further discusses the physico-chemical assessment of soil, synthesis and toxicity of nanoparticles, and post-harvest use of plants. Existing literature suggests that ZnPs, when applied at optimal concentrations, can promote plant growth and yield by enhancing photosynthetic pigment production, protein synthesis, antioxidant enzyme activity, and the phytoavailability of HMs. Although still in the developmental stage, nano-phytoremediation demonstrates substantial potential as a sustainable strategy for the remediation of contaminated environments.

With industrialization and population growth, the greenhouse effect is intensifying, and atmospheric CO₂ levels and regional temperatures are key indicators influencing plant growth and phytoremediation. This study investigates the responses of Noccaea caerulescens to elevated CO₂ (550 ppm, predicted for 2050), increased temperature (3 °C rise), at elevated CO₂, the plant's dry weight increased by 25%, and metal uptake, including Cd, Pb, Cu, and Zn, showed significant improvement compared to ambient conditions. In contrast, temperature rise reduced growth and metal uptake, decreasing phytoremediation efficiency for Cd, Pb, Cu, and Zn by 81%, 72%, 80%, and 84%, respectively. However, the combined effect of elevated CO₂ and temperature resulted in a 44-58% increase in remediation efficiency for these metals, reducing soluble Cu and Pb content in the soil. Additionally, the dual treatment decreased malondialdehyde content by 30% in roots and shoots, suggesting that the synergistic effect of CO₂ and temperature alleviates oxidative stress. These findings highlight that the greenhouse effect can enhance the phytoremediation efficiency of N. caerulescens, offering valuable insights for future environmental management and soil decontamination strategies. This study emphasizes the potential for optimizing phytoremediation under future climate change scenarios to improve soil restoration techniques and promote environmental sustainability.

Plant-colonizing beneficial microbes are effective bio-tools for enhancing phytoremediation. Two-year pot experiment at Punjab Agricultural University, Ludhiana, India, assessed the response of Populus deltoides under nursery conditions to sewage sludge treated soil with indigenous metal-mobilizing Bacillus species-B. thuringiensis (T₁), B. cereus (T₂), B. pumilus (T₃), and their consortium (T₄), with three inorganic fertilizer levels-RDF1-100%, RDF2-75%, and RDF3-50% [Recommended dose of fertilizer (RDF)]. Each inoculated treatment was compared to its respective uninoculated control (C). The application of T₄ with RDF1 significantly increased shoot length and biomass by 13.8 and 32.9% than C, respectively. Bioconcentration factors (BCF) for Cd and Ni increased by over 50% than C demonstrating enhanced phytoremediation efficiency. Elemental accumulation was predominantly localized in roots, with the exception of Zn and Cd. Among most of the parameters, RDF1 × T₄ was statistically comparable with RDF2 × T_4. Irrespective of fertilizer dose, T₄ maximally improved phytoremediation efficiency (BCF) by 0.61 (shoot) and 0.52 (root) compared to 0.20 and 0.16 in C, respectively, as well as soil chemical and biological properties up to 22.3%. These results highlight the potential of indigenous microbial inoculants to reduce soil heavy metals and enable sustainable, enhanced phytoremediation with 25% lower fertilizer input.

The scarcity of freshwater resources compels farmers to utilize wastewater for irrigation. The current study aimed to assess the performance of tomato (Solanum lycopersicum L.) genotypes for potentially toxic elements (PTEs), i.e., Ni, Pb, Mn, Zn, and Cr genetic tolerance. For this purpose, 44 tomato genotypes were grown in the field conditions under sewage water (T1) and canal water (T2) irrigation to screen tolerant and sensitive genotypes based on PTEs accumulation in reproductive and vegetative parts of both treatments. Selected genotypes were validated under hydroponic conditions with the same PTEs concentrations. Gene expression of metallothionein (MT) and heat shock protein (HSP) was assessed using ubiquitin (UBQ) as reference gene. The PB-017906 genotype was selected as the best metal-tolerant, and the 10592 was identified as high-yielding, and thus recommended for commercial production. At 200 μM Pb concentration, target genes, i.e., HSP and MT transcribed profusely 63.27 and 38.81 times, respectively in leaf tissue of "Riograndi" as compared to other genotypes. While in low metal accumulator PB-017906 genotype MT transcription in leaf tissue at 200 and 400 μM Pb concentrations was insignificantly upregulated (1.28 and 1.86 times than control), followed by CLN-2418A. RT-PCR clearly revealed Cr stress induced higher HSP and MT transcription in leaves at 200 µM (2.55 and 4.05 times), and same trend was observed in roots. The upregulation of MT and HSP genes may be attributed to PTEs tolerance mechanism and tolerance capacity largely depends upon the genetic variability of the plant. Current findings highlighted tomato germplasm genetic variability as a basis for PTE tolerance, and selected tolerant genotypes capable of sustainable agriculture under PTE stress. Hence, these genotypes could also be used for breeding tomatoes with low PTEs bioavailability and better yields. This would help to improve food security and environmental protection by allowing more crop production in contaminated regions.

Cadmium (Cd) pollution influences environmental quality and human health, and magnesium (Mg)-modified biochar can efficiently clean Cd. However, to date, the effects and mechanisms of Mg-modified biochar generated from agricultural waste on comprehensive Cd remediation in water, soil, and plant is limited. In this study, the Mg-modified and unmodified biochars were produced from citrus peels. It was found that the surface area and pore volume of modified biochars were higher than those of unmodified biochars. After Mg modification, increase in H/C, O/C, and (O + N)/C ratios indicated Mg-modified biochars had a greater proportion of aromatic structures. In aqueous experiment, maximum Cd adsorption capacity and removal rate were observed in MgBC600, which was 182.24 mg/g and 97.75%. In pot experiment, MgBC600 significantly reduced Cd concentration of pakchoi by 44.40-46.20% and enhanced biomass by 40.68-112.50%. The application of MgBC600 promoted Cd immobilization by converting bioavailable Cd into insoluble forms. Mineral precipitation was the main mechanism (63.82-86.04%) of biochars for Cd remediation. XPS and XRD analysis proved the form of precipitation was CdO, Cd(OH)₂, and CdCO₃. Therefore, this study provides a theoretical basis for the resource utilization of citrus peels and the future application of Mg-modified biochar for environmental purification and safe crop production.