International Journal of Phytoremediation最新文献

Contamination of soil by cadmium is an emerging urgent issue of human concern. The present study was conducted to investigate the effects of 250 mg/kg cadmium chloride (CdCl₂) and 25 ppm of 6-benzylaminopurine (6-BAP) on pigment constitution, ChlM gene expression, antioxidant activity, and secondary metabolite profile in Strobilanthes alternata, a herbaceous plant with excellent Cd phytostabilization potential. The results revealed that 6-BAP could enhance the total chlorophyll (52%) and carotenoid contents (57%), ChlM gene expression (1.4-fold in leaves), glutathione contents (ninefold in roots, onefold in leaves), superoxide dismutase (SOD, 27% in roots, 19% in leaves), catalase (1.5-fold in roots), ascorbate peroxidase (APX, eightfold in roots), and guaiacol peroxidase (GPOX, 3.9-fold in roots) activities in Cd-stressed plants compared to Cd treated S. alternata. The liquid chromatography-mass spectrometry (LC-MS) analysis revealed the presence of putative protective compounds like verproside, atractyloside, 4-(4-hydroxyphenyl)-2-butanone O-[2-galloyl-6-p-coumaroylglucoside], pallidol 3,3″-diglucoside, ent-fisetinidol-(4beta->8)-catechin-(6->4beta)-ent-fisetinidol, (-)-matairesinol 4'-[apiosyl-(1->2)-glucoside], and notoginsenoside Fe only in Cd + 6-BAP treated S. alternata. These results reveal the capability of 6-BAP as an efficient amendment for enhancing heavy metal stress resilience in plants. Further studies are required to validate the efficiency of this method in different plants under field conditions.

Deltamethrin (DMT), a toxic pyrethroid insecticide, contaminates soil and water, posing risks to humans and organisms. Phytoremediation using Plantago major was studied to remove DMT and its metabolites from polluted soil, enhanced by liquid silicon dioxide (SiO₂, 750 mg L^-1) and Bacillus subtilis AZFS3 (B. subtilis),10⁷ CFU/mL) under greenhouse conditions. Our study assessed biochemical responses, including superoxide dismutase (SOD), catalase (CAT), hydrogen peroxide (H₂O₂), malondialdehyde (MDA), and detoxification gene expression in P. major roots and leaves subjected to DMT stress. SiO₂ and B. subtilis desorbed DMT by 46.08 and 18.75 µg g^-1, respectively. The longest half-life (t₁/₂) of DMT was 23.22 days in polluted soil alone, while the shortest (5.81 days) was observed in soil with P. major and B. subtilis. Soil with P. major plus SiO₂ reduced DMT residues more effectively than B. subtilis and increased DMT accumulation in plant tissues. SOD and CAT activity peaked in roots and leaves treated with SiO₂ and B. SUBTILIS, with lower H₂O₂ and MDA contents observed in SiO₂ treatments. Additionally, DMT stress induced significant upregulation of cytochrome P450, glutathione S-transferases (GST), glycosyltransferases (GTs), and ABC transporter genes in P. major. SiO₂ was more effective than B. subtilis in enhancing phytoremediation by promoting DMT degradation and metabolic detoxification pathways. This study highlights the potential of combining SiO₂ and B. subtilis with phytoremediation to accelerate DMT removal and mitigate harmful pesticide residues in polluted soils and plants.

Batch adsorption experiments were carried out to evaluate the removal of Rhodamine B (RhB), a cationic dye, from synthetic wastewater using a multi-walled carbon nanotube/titanium dioxide (MWCNT/TiO₂)-modified biochar composite (CBTM), with pristine biochar (CCB) as a reference. The effects of solution pH, contact time, adsorbent dosage, temperature, and initial dye concentration on adsorption performance were systematically investigated. Maximum RhB removal occurred at pH 3, with equilibrium achieved after 180 min. Under these conditions, CBTM exhibited a higher adsorption capacity (31.43 mg·g^-1) than CCB (17.31 mg·g^-1) at 313 K. Equilibrium data were best described by the Freundlich isotherm, indicating multilayer adsorption on heterogeneous surfaces, while kinetic analysis showed that the pseudo-first-order model provided the most accurate fit, suggesting a physisorption-dominated process. Thermodynamic parameters (ΔG°, ΔH°, ΔS°) confirmed that the adsorption was spontaneous and endothermic. Interestingly, while CBTM demonstrated superior dye removal, antimicrobial assays revealed stronger bacterial inhibition by CCB. These results highlight the potential of CBTM for efficient dye removal and underscore the multifunctional capabilities of biochar-based adsorbents.

Winter evergreen shrubs play a vital role in mitigating atmospheric particulate matter (PM) and potentially toxic elements (PTEs). This study evaluated PM retention and PTE accumulation in four shrub species from northern Jiangsu. Rhododendron × pulchrum exhibited the greatest PM retention (0.1082 mg/cm²) and the highest accumulation of Cr, Mn, Ni, As, Cd, and Pb in both surface deposits and leaf tissues. PM distribution was dominated by coarse particles (PM_>10, 71.60%), followed by PM_2.5-10 (21.60%) and PM_0.2-2.5 (6.81%), with Buxus megistophylla showing superior capacity for fine particle (PM_0.2-2.5) capture. Photinia × fraseri displayed elevated Hg levels (0.040 mg/kg), whereas Pittosporum tobira accumulated the highest Zn concentrations (36.041 mg/kg). Leaf PM load was strongly and positively correlated with most PTEs (p < 0.01). Notably, Cu and Pb in P. tobira leaves and Pb in B. megistophylla leaves were significantly correlated with the corresponding elements in leaf-associated PM (p < 0.05). These results confirm that PM of different size fractions exhibits distinct selective adsorption patterns for atmospheric PTEs. Overall, R. pulchrum appears to be a promising understory shrub species for greening in PTE-contaminated environments.

A 90-day pot study investigated the effect of low-density polyethylene microplastics (LDPE MPs) on bioaugmented phytoremediation of crude oil-contaminated soil using lemongrass (Cymbopogon flexuosus) and Micrococcus luteus WN01 (PGPR). Plant growth, root morphology, root exudates, microbial population, dehydrogenase activity, residual TPH concentration, and LDPE MP degradation were evaluated. M. luteus significantly increased plant biomass and improved TPH degradation by 79.16% and 64.43%, which were 25.04% and 15.85% higher than uninoculated treatments. M. luteus inoculation still led to higher TPH removal compared to uninoculated treatments despite MP-induced alterations in plant biochemical and morphological traits. GC/MS analysis of lemongrass root exudates showed that M. luteus enriched plants with GABA-associated allelochemicals. FTIR analysis indicated accelerated oxidation of LDPE MPs in planted treatments compared to unplanted ones, evidenced by increased absorbance at characteristic peaks (3620.71 cm^-1 O-H stretching, 1651 cm^-1 C=O stretching, and 1031.10 cm^-1 C-O stretching). This strongly suggests a co-metabolic breakdown of LDPE MPs within the plant rhizosphere (a degradation hotspot). Lemongrass essential oil was not significantly affected by the contaminant or M. luteus. This study highlights the lemongrass-M. luteus association as a promising candidate for the remediation of both petroleum- and MP-contaminated soil, with the added benefit of essential oil production.

Constructed wetlands (CWs) offer an eco-friendly wastewater treatment technology which can provide a low-cost alternative to "raw wastewater discharge" which although is increasingly becoming unsustainable, remains the most common practice for urban housing colonies in India. This study demonstrates that despite being a semi-engineered system CWs can provide consistent removal efficiency while treating "grey water", which constitutes the major fraction of the total wastewater generated in an urban housing colony. The lack of field-scale performance data for CWs has kept builders, practicing engineers, and policy makers thus far unconvinced about their true potential beyond scientific publications. The work presented here provides comparative assessment of phytoremediation potential of two macrophytes Canna indica and Ageratum conyzoides while treating grey water emanating from a nearby urban housing colony. How the relative positioning of these macrophytes, upstream or downstream of each other, can influence the wastewater treatment efficiency was also evaluated. Higher removal efficiencies were observed for inorganic nitrogen (43.4%) and phosphate (45.68%) for CWs vegetated with Canna indica while higher sulfate removal efficiency (63.5%) was observed for CWs vegetated with Ageratum conyzoides. For chemical oxygen demand (COD) and total suspended solids (TSSs), removal efficiencies remained consistently above 65% and 80%, respectively.

Modeling and predicting heavy metal uptake by plants using organic amendments helps reduce metal concentrations in contaminated soils. This study examined the effects of 1% and 2% (W/W) biochar and urban waste compost on the growth and cadmium (Cd) and lead (Pb) uptake by Bromus tomentellus in contaminated soil. The highest plant height (34.0 cm) and biomass (30.0 g) occurred with 2% biochar, compared to 16.0 cm and 9.0 g in control. For Pb, the maximum bioconcentration factor (BCF) was 2.25 with 1% compost, and the highest translocation factor (TF) was 1.4 with 2% biochar. For Cd, both max BCF (3.40) and TF (1.4) were seen at 1% biochar. Metal uptake and transfer significantly correlated with biomass and soil factors such as fertility (N, P, and K), pH, sodium adsorption ratio (SAR), and organic matter (OM) (Mantel test: p = 0.1, r = 0.4). The Group Method of Data Handling (GMDH) model, with high accuracy (R² = 0.998), showed compost caused an initial rise then decline in Cd uptake, while biochar had the opposite effect. Pb uptake increased with compost up to 1.052%, peaking at 763.7 ppm, then decreased. The GMDH model can optimize biochar or compost levels to enhance metal uptake by plants in polluted soils.

The growing need for sustainable agricultural practices has prompted the exploration of microbial biotechnologies, specifically plant growth-promoting rhizobacteria (PGPR), as alternatives to chemical fertilizers and pesticides. This study focuses on Bacillus cereus strain doms B16, a newly isolated bacterium from the rhizosphere of black pepper plants. Our comprehensive evaluation revealed that strain B16 exhibits multiple beneficial traits such as phosphate solubilization, nitrogen fixation, siderophore production, and the synthesis of indole-3-acetic acid (IAA), which are pivotal for enhancing plant growth. The results from pot experiments show that B16 significantly improves growth parameters in mustard, green gram, and bengal gram, confirming its potential to contribute to eco-friendly agricultural practices. The strain's robustness in salt stress conditions and its ability to form biofilms further affirm its potential as a biofertilizer. These findings underscore the significance of Bacillus cereus strain doms B16 in promoting sustainable agriculture through enhanced plant health and productivity, presenting a viable, eco-friendly alternative to conventional agricultural inputs.

This study investigates the potential of Citrus paradisi peel (CP) as biosorbent for the elimination of Rhodamine B (RhD B) from wastewater. The study used FTIR, SEM and EDX to determine the structure of CP. It was shown that 1.4 and 2.0 g were the optimal biosorbent doses for plain and treated peels, respectively. A number of factors were optimized in order to examine the sorbent efficiency for Rhodamine-B dye. Simple and acid-modified biosorbents were employed in batch mode processing to remove hazardous basic dyes such as rhodamine-B. Adsorption equilibrium was achieved within 60 min, and treated grapefruit peels (TTCP) were found to be more effective than untreated grapefruit peels (UCP). Kinetic studies outcomes showed that the pseudo-second-order kinetics form fit more with an R2 of ≥ 0.916 and ≥ 0.932 for UCP and TTCP respectively. The adsorption isotherm of Langmuir was used to describe equilibrium for TTCP, with highest sorption ability of 321.507 µg/g. The study also discovered that 1 M HCl and NaOH may be used to regenerate CP, with recovery rates of RhD B reaching up to 98% and 85%, respectively indicating CP is a potential biosorbent for removing RhD B from aqueous solutions.

The plant species used in constructed wetlands are mainly aquatic herbaceous, most of which tend to die during winter in subtropical areas. At present, very few studies have examined the performance of woody plants in constructed wetlands. In order to increase plant diversity and improve purification ability of vertical-flow constructed wetland during winter, 10 woody plant species were tested by establishing the microcosms simulating vertical-flow constructed wetlands. Their applicability was integrally evaluated, on basis of their adaptability, rhizospheric enzyme activity, and rhizospheric microbial diversity. The results showed that (1) seven woody plant species, Adina rubella, Salix rosthornii, Callicarpa dichotoma, Nerium oleander, Hibiscus mutabilis, Ligustrum obtusifolium, and Ligustrum lucidum could survive in the simulated vertical-flow constructed wetland; (2) N. oleander and C. dichotoma had higher nitrogen (N) and phosphorous (P) absorption capacity; (3) according to the integral evaluation, N. oleander, C. dichotoma, and S. rosthornii have excellent applicability for vertical-flow constructed wetland; A. rubella and H. mutabilis have moderate applicability; L. obtusifolium and L. lucidum have poor applicability; Ligustrum. japonicum "Howardii", Pittosporum. tobira and Distylium. buxifolium, were not applicable to vertical-flow constructed wetland. N. oleander, C. dichotoma, and S. rosthornii are recommended for application in vertical-flow constructed wetland.