International Journal of Phytoremediation最新文献

Vegetated ditches have been demonstrated to be an effective method for pollutant remediation. This study assesses the removal potential and pathways for herbicide runoff pollution utilizing Canna indica, Thalia dealbata, Typha latifolia, and Juncus effuses ditches. Resultes show these vegetated ditches significantly outperform unvegetated ones in removing atrazine and diuron during runoff events (p < 0.05). The removal rates of atrazine and diuron varied among the four aquatic macrophytes, with C. indica and T. latifolia exhibiting the highest efficiencies, achieving 43.02-72.61% and 56.42-53.11% removal, respectively, under varying runoff pollution. The half-lives of herbicides were significantly reduced from 231.01 to 693.15 h in unvegetated ditches to 99.02-230.05 h in vegetated ones. Furthermore, the release rates of herbicides were significantly reduced from 48.95 to 55.79% in unvegetated ditches to 34.10-42.32% in vegetated ones, particularly during high-dose rainfall events (p < 0.05). Mass balance analysis indicated that biodegradation was the primary removal pathway for herbicides (atrazine 36.20%; diuron 45.76%), followed by sorption (atrazine 6.00%; diuron 12.19%) in vegetated ditches. Plants boosted biodegradation, by 0.5 times for diuron and 1 time for atrazine. The study confirms that vegetated ditches effectively reduce herbicide runoff pollution.

Lead (Pb) pollution in soil affects growth of plants. Plants' endogenous hormones play an important role in resistance to Pb of plant. In order to explore the hormone-based mechanisms of Pb accumulationin in hyperaccumulator Arabis alpina, a pot experiment was conducted to analyze the contents of endogenous hormones (auxin, gibberellin, abscisic acid, and cytokinin) and related genes expressions, and Pb contents of A. alpina, as well as the transporter (cation exchangers (CAX), heavy metal ATPases (HMA), and ATP-binding cassette (ABC)) concentrations under foliar spraying of indoleacetic acid (IAA). The results showed that the soluble components (vacuoles) Pb contents under 300 mg kg^-1 Pb²⁺ treatment in shoots and roots increased by 238.8% and 896.3%, respectively, compared to 100 mg kg^-1 Pb²⁺ treatment. The content of endogenous hormones in leaves and roots increased under increasing Pb-treatment concentrations. Compared with the control (0 mg kg^-1 Pb²⁺ treatment), the content of auxin in roots and leaves under the 100 mg kg^-1 Pb treatment increased by 176.2% and 585.3%, respectively. The auxin content in xylem saps under the 100 and 300 mg kg^-1 Pb treatments increased by 283.1% and 100.3%, respectively. The gene expression related to auxin transport was up-regulated. The expression of three genes related to the auxin-repressed 12.5 kDa protein and the auxin-responsive GH3 (Gretchen Hagen 3) family were down-regulated. Under foliar spraying of IAA, the Pb content in leaves increased by 29.81%, and the Pb content in the symplast sap was higher than that without IAA spraying treatment. The concentrations of CAX and HMA in the roots of A. alpina increased by 9.6% and 8.8%, respectively, with foliar spraying treatment with IAA, while the ABC concentration decreased by 21.9%. In general, the transport and accumulation of Pb is related to the IAA content and the gene expression of AaGDCST, a signal transducer for inducing increased concentrations of the transporter CAX and HMA in the roots of A. alpina. Pb transport via the symplast pathway under IAA application. Regarding the Pb hyperaccumulation of A. alpina, gene AaGDCST has the potential to be utilized as a candidate gene.

The flowing-water remediation of contaminated soil was investigated. Urease combined with biochar (UCB) technology was used to handle the Pb²⁺-contaminated sand column. The results showed that with the continuous increase of pore volume, the concentration of Pb²⁺ in the leachate undergoes three stages: slow growth, rapid growth, and steady state. With increasing seepage velocity, the concentration of Pb²⁺ in leachate increased slightly. The residual amount of each section of the sand column gradually decreased with increasing migration distance. The comparative results indicated that the UCB technology had a good solidification effect on Pb²⁺. This was due to urease-induced CaCO₃ precipitation, cementation, and adsorption of Pb²⁺. Biochar provided more nucleation sites for urease, and some Pb²⁺ was adsorbed on its surface or diffused into the pores of biochar, or ions exchanged with functional groups on the surface of biochar, which effectively stabilized the free Pb²⁺.

High fluoride (F) concentrations negatively affect the seed germination, plant growth, development, and yield of crops. Phaseolus vulgaris L. is an F-sensitive crop frequently grown on marginal lands affected by F salts. Selenium (Se) is a vital elicitor of the antioxidative enzymes involved in scavenging free radicals to alleviate abiotic stress. Recent studies have demonstrated that engineered nanoparticles (NPs) have the potential to induce tolerance to abiotic stress in plants. Phytosynthesis of NPs is a novel and sustainable approach to mitigate abiotic stresses. The present study was intended to assess the role of green synthesized Se-nanoparticles (Se-NPs) in improving the physiochemical attributes, growth, and F stress tolerance of P. vulgaris growing in 200 ppm sodium fluoride (NaF) stress. NaF toxicity reduced Chl a, Chl b, and carotenoid content by 88.8%, 95.5%, and 96% compared to control with maximum improvement obtained through phyto-nano seed priming and foliar spray of 70 ppm Se-NPs. The joint treatment of NPs application through seed priming and foliar spray improved stomatal conductance (14.2%) and transpiration rate (11.7%) in plants subjected to NaF stress. The protein content (91.02%) and DPPH activity (33.72%) decreased under NaF stress, which was improved by phyto-nano seed priming and foliar spray (14.10%). Furthermore, the integrated application of Se-NPs seed priming and foliar spray increased nutritional content (P, K, Ca, Mg, and Zn), proline, ascorbic acid, and phenol yet reduced the level of NaF in plants. Se-NPs at 70 ppm were found to be more effective than 60 ppm in all modes of applications. Our results reveal a perception that Se-NPs increase P. vulgaris growth in NaF stress conditions, perhaps through a multipronged approach: improving photosynthetic content, nutrient uptake, and yield of P. vulgaris. Consequently, the findings of this study may be used for breeding and screening F-tolerant cultivars.

The concurrently occurring multiple abiotic stresses like salinity and heavy metals (Nickel) pose a serious threat to plant survival and food security worldwide, especially in the face of climate change. Therefore, it is imperative to continuously test and study the plant's physiological changes under combinations of abiotic stresses to ensure sustainability and food security. An experiment was conducted to study the interactive effects of salinity (0, 7.5, and 15 dS m^-1) and Ni toxicity (0, 10, 20, and 40 mg kg^-1) on a tolerant (Naqeeb) and a sensitive (Nadir) Solanum lycopersicum L. physiology and fruit quality in the soil. At maturity (50% fruit ripening), the plant growth and physiological characteristics were measured, revealing that the tolerant genotype exhibited the higher values for plant height, dry weight, potassium, membrane stability index (MSI), and antioxidant enzymes (superoxide dismutase; SOD, catalase; CAT, ascorbate peroxidase; APX, and glutathione reductase; GR). Additionally, it showed enhancement in fruit yield, size, and quality. Conversely, the tolerant genotypes showed a lower reduction in terms of plant height (25.4%) and plant dry weight (41.9%) compared to sensitive genotype (30.1 and 51.4%, respectively). Additionally, the tolerant genotype demonstrated lower values of Ni and Na⁺ concentration and MDA accumulation under the combined stress of salt and Ni, compared to the sensitive genotype. Furthermore, the study indicated that Ni at a concentration of 10 mg kg^-1 significantly influenced tomato plant growth by enhancing its nutritional efficiency and competing with Na⁺. However, Ni at concentrations of 20 and 40 mg kg^-1 had toxic effects on the plants, leading to a decrease in plant growth and physiological processes. Moreover, a negative relationship was observed between Ni uptake and Na⁺ uptake, while a positive relationship was observed between Ni and K⁺ uptake. Overall, this study provides valuable insights into the interaction between salinity, heavy metal toxicity, and tomato plant physiology, contributing to the development of sustainable agricultural practices.

Anthropogenic activities have accelerated lead (Pb) accumulation across different trophic levels in the ecosystem. This study focused on the physiological mechanisms of an invasive plant, Alternanthera tenella in a controlled hydroponic setting to understand its response to Pb stress. A. tenella was exposed to 680 µM of lead acetate for 21 days, showing high tolerance (83%) with minimal growth inhibition. Pb exposure altered macro- and micronutrient concentrations, suggesting essential mineral reallocation to enhance stress tolerance. Scanning electron microscopy (SEM) revealed Pb²⁺ depositions in the vacuoles and cell walls of root (∼14%) and leaf (∼3%) cells, a key mechanism for reducing Pb toxicity. Fourier transform infrared spectroscopy (FTIR) indicated that Pb²⁺ ions interacted with hydroxyl (-OH) and amide (CO-NH) groups, important for metal ion complexation. Physiological responses included increased proline, malondialdehyde, protein degradation, and elevated catalase (CAT) and ascorbate peroxidase (POD) activity. A. tenella accumulated 46,866.92 mg/kg DW of Pb, primarily in roots (2682.5 mg/kg DW), with limited Pb translocation to shoots, suggesting a protective mechanism. High biological concentration (BCF 19.04) highlight its potential for Pb phytostabilization. These findings are specific to hydroponic conditions, and further research is needed to assess its phytoremediation potential in field conditions.

Phytoremediation is an effective and sustainable method for removing pollutants from wastewater. This study investigates the phytoremediation capabilities of Limoniastrum guyonianum, a halophytic Saharan plant species, for excess phosphorus and nitrogen in domestic wastewater. The plants were sourced from the "Halloufa" wetland, a wastewater discharge area in the north of El-Oued, south-eastern Algeria. The research was conducted using pilot-scale circular beds designed for phytoremediation, each with an 18-liter capacity, filled with layers of gravel and a clay-sand mixture. These beds were part of a vertical surface flow system at the National Sanitation Office (ONA) domestic wastewater treatment facility in El-Oued, Algeria. The results demonstrated significant improvements in water quality parameters. Treatment with L. guyonianum reduced pH values from 8.07 to 7.64 and decreased turbidity from 116.25 NTU to 8.87 NTU. The mean concentration values of ammonia, phosphate, and biochemical oxygen demand (BOD₅) were reduced by 99.22%, 55.58%, and 78.6%, respectively. The study concludes that L. guyonianum is highly efficient in remediating nitrogen contaminants, effective in reducing phosphorus levels, and capable of lowering biochemical oxygen demand. L. guyonianum presents a nontoxic, eco-friendly, and cost-effective alternative for wastewater treatment in the "Halloufa" wetland, highlighting its potential for application in bioremediation processes.

Atmospheric particulate matter (PM) emission from overpasses is serious. To optimize the solution of planting design in the overpass, it is essential to understand the plant's ability to capture PM. In this study, leaf samples were collected from 11 plant species commonly existing in five overpass greening areas in Changsha, China. The PM retention per unit leaf area (M_leaf), PM retention on a unit greening land (M_land), and leaf surface microstructure were measured and analyzed. Results showed that the M_leaf of Ophiopogon japonicus (1.59 g/m²) exhibited the highest value, and that of Nandina domestica (0.23 g/m²) was the lowest value. The M_land of O. japonicus, Fatsia japonica, and Magnolia grandiflora was the highest based on the leaf area index. Leaves with wide gullies and cuticular wax significantly affected the PM retention ability of plants. Plant height played an important role in the PM retention ability in the overpass. Multilayered canopy structures such as arbor-shrub-herb had great potential for PM retention in overpasses. Based on the results, a PM retention design scheme of overpass greening space was proposed. This study provided an optimal solution for providing critical insights and guidance for developing effective PM reduction strategies in urban overpass environments.

Synthetic dyes are a major source of environmental pollution. In this regard, biosorption is an important treatment method for the removal and detoxification of synthetic dyes from aqueous solutions. Accordingly, the present study was conducted to investigate the potential of Robinia pseudoacacia L. biosorbent (RPF) in the removal of crystal violet (CV) dye from aqueous solutions. To this end, biosorption parameters, including zero charge point, pH, initial dye concentration, biosorbent dose, stirring speed, and temperature, were investigated. Variations in the treated and untreated biosorbent surfaces were characterized using FTIR spectroscopy. The results showed that the RPF biosorbent removed 77% of CV under optimal conditions: pH of 6, initial dye concentration of 10 mg/L, biosorbent dose of 1 g, contact time of 30 min, stirring speed of 150 rpm, and temperature of 298 K. The Dubinin-Radushkevich isotherm (R²= 0.976) and pseudo-second-order kinetic (R² = 0.995) models were well fitted according to isotherm and kinetic studies. Thermodynamic studies revealed that the process was endothermic according to the ΔG values. Moreover, the phytotoxicity of treated CV solutions was significantly reduced. Thus, the RPF biosorbent was determined to be a low-cost, sustainable, and ecofriendly material for the removal and detoxification of synthetic dyes from aqueous solutions.

Rice is the staple food for 1/3 of the world's population, but soil pollution with cadmium (Cd) is harmful to rice production and human health. Therefore, how to reduce the Cd content in rice grains is a hot topic worldwide. However, so far, little is known about Cd remediation technologies for paddy soils from the perspective of patents. Therefore, a meta-analysis was performed to assess the effects of measures based on 1402 observations from 336 patents from 2011 to 2021. The spatio-temporal analysis showed that the number of patents was positively related to the general economic development of the country, but hardly related to the regional economy or the level of provincal Cd pollution. The meta-analysis showed that the overall effect of Cd reduction was slightly higher for combined technologies (59%) than for single technologies (57%). Among all technology classifications, soil applications, which are mainly based on nutritional elements, were the most commonly used technology that could reduce the Cd content in rice grains by 57%. The plant biotechnology was the most effective and could reduce Cd content in rice grains by 76%. Further analysis showed that macronutrients (calcium, phosphorus, and sulfur) were preferred in soil amendments, while micronutrients (silicon, zinc, and selenium) were preferred in foliar amendments. NRAMP5 and HMA3 were the most important genes for manipulating Cd uptake in rice, while Bacillus and Pseudomonas were the most important bacterial taxa for bioremediation of Cd. Overall, this study compiled data on Cd remediation of paddy soil from 10 years of Chinese patents, providing a theoretical basis for better production of low Cd crops and protection of human health.