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The objective of this study was to determine the efficiency of the microbial rhizosphere ( Canavalia ensiformis ) in the phytoremediation of sulfentrazone using quantification methods (CO2 evolution, microbial biomass carbon, and metabolic quotient) and identification of bacteria (PCR-DGGE technique). The experiment was conducted in a completely randomized design, in a 2x4 factorial scheme, with four replications. The treatments were composed of rhizospheric soil (cultivated with C. ensiformis ) and non-rhizosphere soil (uncultivated soil); and four levels of contamination by sulfentrazone (0, 200, 400, and 800 g ha -1 a.i.). The microbiota associated with the rhizosphere of C. ensiformis efficiently reduced sulfentrazone residues in the soil, with better performance at the dose of 200 g ha -1 a.i. Using the PCR-DGGE technique allowed the distinction of two profiles of bacteria in the rhizospheric activity of C. ensiformis . The second bacterial profile formed was more efficient in decontaminating soil contaminated with sulfentrazone residue. The microbiota associated with the rhizosphere of C. ensiformis has an efficient profile in decontaminating soils with residues equivalent to 200 g ha -1 a.i. the herbicide sulfentrazone.

Nitrogen (N) plays an important role in plant growth and developmental metabolic processes, research on nitrogen speciation regulating Cd accumulation in duckweed is still limited. In this study, the effects of three nitrogen sources (NH 4 Cl, Ca(NO 3 ) 2 and NH 4 NO 3 ) on the growth, Cd accumulation, and photosynthetic parameters of Landoltia punctata ( L. punctata ) were analyzed. The results showed that Cd enrichment in L. punctata was significantly reduced ( p <  0.05) with different nitrogen treatments compared to the control (CK). Ammonium nitrogen (NH 4 -N) is more conducive to the accumulation of Cd in L. punctata than nitrate nitrogen (NO 3 -N). The sum of the cell wall components and soluble components of Cd in the NH 4 -N treatment group was greater than that in the NO 3 -N treatment group. The proportion of F NaCl extracts in the NH 4 -N treatment group was greater than in the NO 3 -N treatment group. NO 3 -N led to a greater reduction in photosynthetic pigment content than NH 4 -N. Overall, applying different forms of nitrogen can alleviate Cd toxicity in L. punctata , and the detoxification effect of the NH 4 -N treatment is stronger than that of NO 3 -N treatment. This study will provide theoretical and practical support for the application of duckweed in Cd phytoremediation even in eutrophic aquatic environments.

Soil salinity is a significant abiotic stress and poses risks to environmental sustainability. Thus, the improvement of the time for recovering the salt-affect soil is crucial for the phytoextraction process using halophytes plants, especially regarding on nutritional management. We evaluated the responses of Atriplex nummularia Lindl. to nitrogen (N) and phosphorus (P) under different salinity levels. The treatments comprised doses of N (N1 = 80 kg ha -1 ) and P (P1 = 60 kg ha -1 ): (1) without N and P (N0P0) (control); (2) with N and without P (N1P0); (3) without N and with P (N0P1); and (4) with N and P (N1P1) and five levels of electrical conductivity from irrigation water: 0.08, 1.7, 4.8, 8.6, and 12.5 dS m -1 . The. We evaluated dry biomass of leaves, stems, and roots 93 days after transplantation. We also assessed the leaf and osmotic water potential, the osmotic adjustment, and the nutrient contents (N, P, Na, and K). N application increased 22.3, 17.8, and 32.8% the leaf biomass, stem biomass, and osmotic adjustment, respectively; and consequently, boosts Na extraction in 27.8%. Thus, the time of the phytoextraction process can be improved with N fertilizer at a rate of 80 kg ha -1 .

This study aimed to examine the potential of soil amendment-assisted phytoremediation using ryegrass in reclaiming abandoned gold mine soil in southwestern Ghana, with a specific focus on the soil contamination hazards associated with metals and metalloids. A pot experiment lasting 60 days was carried out to assess the efficacy of soil amendments, such as compost, iron oxide, and poultry manure, in mitigating environmental hazards. Three soil contamination indices (soil contamination = CF, enrichment factor = ER, and pollution load index = PLI) were used to calculate the extent of soil contamination, enrichment, and pollution of the sites with Co, Hg, Ni, Mo, Se, Sb, and Pb. The findings show that Hg made the greatest contribution (with a maximum soil CF of 18.0) to the overall PLI, with a maximum value of 74.4. The sites were averagely and consequently enriched with toxic elements in the decreasing order: Ni (ER = 33.3) > Mo (20.5) > Sb (14.1) > Pb (11.0) > Hg (7.9) > Se (2.1). The bioaccumulation factor (BCF > 1) suggests that ryegrass has the ability to phytostabilize Co, Hg, Mo, and Ni. This means that the plant may store these elements in its roots, potentially decreasing their negative effects on the environment and human health. Ultimately, the addition of combined manure with iron oxides might have augmented the sequestration of these metals in the root. The elements may have accumulated through sorption on manure or Fe surfaces, dissolution from watering the plants in the pot, or mineralization of organic manure. Thus, ryegrass has shown potential for phytostabilisation of Co, Hg, Mo, and Ni when assisted with a combination of manure and iron oxides; and can consequently mitigate the environmental and human health impacts.

The increasing levels of cadmium (Cd) pollution in agricultural soil reduces plant growth and yield. This study aims to determine the impact of green synthesized zinc oxide nanoparticles (ZnO-NPs) on the physiochemical activities, nutrition, growth, and yield of Zea mays L. under Cd stress conditions. For this purpose, ZnO-NPs (450 ppm and 600 ppm) synthesized from Syzygium aromaticum were applied through foliar spray to Z. mays and also used as seed priming agents. A significant decline in plant height (35.24%), biomass production (43.86%), mineral content, gas exchange attributes, and yield (37.62%) was observed in Cd-spiked plants compared to the control. While, 450 ppm ZnO-NPs primed seed increased plant height (18.46%), total chlorophyll (80.07%), improved ascorbic acid (25.10%), DPPH activity (26.66%), and soil mineral uptake (Mg +2 (38.86%), K + (27.83%), and Zn +2 (43.68%) as compared to plants only spiked with Cd. On the contrary, the foliar-applied 450 ppm ZnO-NPs increased plant height (8.22%), total chlorophyll content (73.59%), ascorbic acid (21.39%), and DPPH activity (17.61%) and yield parameters; cob diameter (19.45%), and kernels numbers 6.35% enhanced compared to plants that were spiked only with Cd. The findings of the current study pave the way for safer and more cost-effective crop production in Cd-stressed soils by using green synthesized NPs and provide deep insights into the underlying mechanisms of NPs treatment at the molecular level to provide compelling evidence for the use of NPs in improving plant growth and yield.

Vesicular sequestration is a potential strategy for enhancing plant tolerance to cadmium (Cd) and arsenic (As). In this study, the ectopic overexpression of yeast-derived ScSMF2 in Arabidopsis thaliana was found to enhance the accumulation and tolerance of Cd and As in transgenic plants. ScSMF2 was localized on vacuole membranes and formed puncta structures in plant cells when agro-infiltrated for transient expression. Transgenic Arabidopsis showed less retardation on root elongation and shoot weight and more accumulation of Cd, As (III) and As (V) when cultured on medium containing Cd or As. Overexpression of ScSMF2 promoted accumulation of Cd and arsenic in transgenic Arabidopsis, which were over twice higher than in WT plants when cultured in soil. This study provides insights into the mechanisms involved in the vesicular sequestration of heavy metals in plant and presents a potential strategy for enhancing the phytoremediation capacity of plants toward heavy metals.

Coal mining disperses heavy metals into the environment, necessitating the identification of metal-tolerant plants for ecosystem restoration. This study evaluated the phytoremediation potential of plant species in abandoned coal wastes in northern Iran. Pollution indices indicated moderate contamination of Cu, Ni, V, Zn, Pb, Cr, and As in coal wastes. The plants varied in their ability to accumulate and translocate these metals, with most showing efficient root-to-shoot translocation. Artemisia scoparia (41.06 mg.kg -1 ) and Capparis spinosa (42.48 mg.kg -1 ) were effective for Cu phytoextraction. Most species, notably Cynodon dactylon (3.4 mg.kg -1 ), showed promise for phytoextraction of Cr. Capparis spinosa (7.67 mg.kg -1 ) exhibited potential for Pb phytoextraction. Most plants, particularly Hordeum vulgare and Melica persica , were effective phytoextractors of Ni. Sylibum marianum accumulated V beyond phytotoxic levels. Chenopodium album and Glaucium fimbriligerum were identified as phytoextractors of Zn while Cynodon dactylon and Hordeum vulgare , accumulating >100 mg.kg -1 Zn in roots, showed potential for phytostabilization. Sylibum marianum and Glaucium fimbriligerum , acted as excluders for As. Kochia prostrata and Artemisia aucheri were excluders for Cu, Cr, Ni, and Pb. This study provided the role of multiple indigenous plants, including perennials and annuals with diverse life forms, in metal extraction and stabilization for sustainable coal waste management.

Electrolytic manganese slag (EMR) is a solid waste generated in the manganese hydrometallurgy process. It not only takes up significant land space but also contains Mn 2+ , which can lead to environmental contamination. There is a need for research on the treatment and utilization of EMR. Improved EMR substrate for Pennisetum sinese Roxb growth was determined in pot planting experiments. The study tested the effects of leaching solution, microorganisms, leaf cell structures, and growth data. Results indicated a substrate of 45% EMR, 40% phosphogypsum, 5% Hericium erinaceus fungi residue, 5% quicklime, and 5% dolomite sand significantly increased the available phosphorus content (135.54 ± 2.88 μg·g -1 ) by 17.95 times, compared to pure soil, and enhanced the relative abundance of dominant bacteria. After 240 days, the plant height (147.00 ± 0.52 cm), number of tillers (6), and aerial dry weight (144.00 ± 15.99g) of Pennisetum sinese Roxb increased by 5.81%, 200%, and 32.58%, respectively. Analyses of leaves and leaching solution revealed that the highest leaf Mn content (46.84 ± 2.91 μg·g -1 ) being 3.38 times higher than in pure soil, and the leaching solution Mn content (0.66 ± 0.13 μg·g -1 ) was lowest. Our study suggested P. sinese Roxb grown in an improved EMR substrate could be a feasible option for solidification treatment and resource utilization of EMR.

This article seeks to evaluate the scientific landscape of the phytoremediation of mine tailings through a series of bibliometric and scientometric techniques. Phytoremediation has emerged as a sustainable approach to remediate metal-contaminated mine waste areas. A scientometric analysis of 913 publications indexed in Web of Science from 1999 to 2023 was conducted using CiteSpace. The results reveal an expanding, interdisciplinary field with environmental sciences as the core category. Keyword analysis of 561 nodes and 2,825 links shows a focus on plant-metal interactions, microbial partnerships, bioavailability, and field validation. Co-citation analysis of 1,032 nodes and 2,944 links identifies seminal works on native species, plant-microbe interactions, and amendments. Temporal mapping of 15 co-citation clusters indicates a progression from early risk assessments and native plant inquiries to integrated biological systems, economic feasibility, and sustainability considerations. Recent trends emphasize multidimensional factors influencing adoption, such as plant-soil-microbe interactions, organic amendments, and field-scale performance evaluation. The findings demonstrate an intensifying translation of phytoremediation from scientific novelty to engineering practice. This quantitative and qualitative analysis of research trends aids in understanding the development of phytoremediation for mine tailings. The results provide valuable insights for researchers and practitioners in this evolving field.

The efficacy of SA foliar use on Pb and Ni-induced stress tolerance and phytoremediation potential by Portulaca oleraceae L. were assayed as a factorial trial based on a completely randomized design with four repetitions. The factors included; SA foliar application (0 and 100 µM) and HMs application of Pb [0, 150, and 225 mg kg -1 soil Lead (II) nitrate] and Ni [0, 220, and 330 mg kg -1 soil Nickel (II) nitrate]. Plant height, stem diameter, shoot and root fresh and dry weight, photosynthetic pigments, total soluble proteins, palmitic acid, stearic acid, arachidic acid, and some macro- and micro-elements contents were reduced facing the HMs stress, but SA foliar application ameliorated these traits. HMs stress increased malondialdehyde content, total antioxidant activity, total flavonoids, phenolics, and linolenic acid content, while SA foliar application declined the mentioned parameters. Moreover, shoot and root Pb and Ni content enhanced in the purslane plants supplemented by SA under the HMs stress. The results propose SA foliar application as a reliable methodology to recover purslane growth characters and fatty acid profiles in the soil contaminated with the HMs. The idea is that SA would be potentially effective in alleviating HMs contamination while keeping reasonable phytoremediation potential.

The biochemical response of plants exposed to pesticides and inoculated with microorganisms is of great importance to explore cleaning up strategies for contaminated sites with pyrethroid-based pesticides. We evaluated the effects of a Trichoderma consortium on the biochemical responses of Echinochloa polystachya plants during the removal of a pyrethroid-based pesticide. Plants were inoculated or not with the Trichoderma consortium and exposed to commercial pesticide H24 ® , based on pyrethroids. Pesticide application resulted in significant reduction in root protein content (58%), but enhanced content of malondialdehyde (MDA) in shoots, superoxide dismutase (SOD) activity in shoots and roots, and catalase (CAT) activity in roots. Inoculation of Trichoderma consortium in E. polystachya exposed to the pesticide resulted in increased protein content in roots and MDA content in shoots (2-fold). Trichoderma consortium improved protein content and SOD activity (140-fold) in plants. Fungal inoculation increased the removal (97.9%) of the pesticide in comparison to the sole effect of plants (33.9%). Results allow further understanding about the responses of the interaction between plants and root-associated fungi to improving the assisted-phytoremediation of solid matrices contaminated with organic pesticides.

Moso bamboo is excellent candidate for cadmium (Cd)/lead (Pb) phytoremediation, while rhizosphere microbiome has significant impact on phytoremediation efficiency of host plant. However, little is known about the rhizosphere bacterial communities of moso bamboo in Cd/Pb contaminated soils. Therefore, this study investigated the assembly patterns and key taxa of rhizosphere bacterial communities of moso bamboo in Cd/Pb polluted and unpolluted soils, by field sampling, chemical analysis, and 16S rRNA gene sequencing. The results indicated α-diversity between Cd/Pb polluted and unpolluted soils showed a similar pattern ( p  > 0.05), while β-diversity was significantly different ( p  < 0.05). The relative abundance analysis indicated α-proteobacteria (37%) and actinobacteria (31%) were dominant in Cd/Pb polluted soils, while γ-proteobacteria (40%) and α-proteobacteria (22%) were dominant in unpolluted soils. Co-occurrence network analysis indicated microbial networks were less complex and more negative in polluted soils than in unpolluted soils. Mantel analysis indicated soil available phosphorus, organic matter, and available Pb were the most important environmental factors affecting microbial community structure. Correlation analysis showed 11 bacterial genera were significantly positively related to Cd/Pb. Overall, this study identified the bacterial community composition of bamboo rhizosphere in responding to Cd/Pb contamination and provides a theoretical basis for microbe-assistant phytoremediation in the future.

Arbuscular mycorrhizal fungi (AMF) have different biological mechanisms to alleviate stressful conditions in heavy metals (HMs) polluted soil. These mechanisms were widely assessed under controlled/greenhouse conditions, but scarcely studied at pilot or territory scale. The aim of this study was to evaluate the response of two Rhizophagus intraradices strains isolated from soils with different histories of pollution, in association with Senecio bonariensis plants, growing in an engineering vegetal depuration module filled with artificially HMs polluted substrate. Plants inoculated with GC3 strain uptook low amounts of HMs and translocated them to shoot biomass. Heavy metals (Mg, Zn, Mn, Cr, Cu and Ni) and macronutrients (Ca, K, S and P) were accumulated in roots of S. bonariensis when inoculated with GB8 strain, limiting their translocation to the shoot. Uninoculated plants showed high translocation of all studied elements to shoot tissues. Concluding, tested R. intraradices strains have exhibited different phytoprotection mechanisms under extremely toxic concentrations of HMs. Moreover, the development of the assay at such a high Technological Readiness Level represents a novel contribution in this field of study.

The widespread use of petroleum-based fuels poses a significant environmental problem due to the risks associated with accidental spills. Among the treatments available, phytoremediation is increasingly accepted as an effective and low-cost solution. This study aimed to evaluate the degradation of the aromatic fraction of biodiesel B10 and the soil fertility analysis in artificially contaminated soils treated with phytoremediation. The experimental design consisted of a 3x3 factorial, with three types of soil treatment: control, autoclaved, and planted with C. ensiformis L , and three levels of B10 biodiesel contamination: 0, 1, and 2%, to simulate spills of 30,000 and 60,000 L ha -1 . The soil was analyzed at three depths: 0-10, 10-20, and 20-30 cm. The results indicated that aromatic compound degradation after phytoremediation was superior to 92,76% and 88,65% for 1% and 2% B10 soil contamination, respectively. The fuel contamination affected soil fertility, reducing the availability of phosphorus and zinc while increasing the Total Organic Carbon (TOC), pH, and the availability of manganese and iron for plants.

In India, ∼30% of total land is degraded due to pollution, salinization, and nutrient loss. Change in soil-quality at urban waste-dumping site prior and after cow-dung amendment was compared with control agriculture soil. The soil at waste-dumping site had elevated pH, EC, temperature and lowered OC and NPK concentrations when compared to control. Polymetallic pollution of Cr, Cd, Pb, and Ni beyond permissible limits was obtained. Cow-dung amendment restored soil physicochemical properties at the waste-dumping site, with increasing soil moisture, CEC and OC; however, a slight change in soil bulk-density and heavy-metal concentration post-amendment was noted. The seven natural colonizers present at the waste-dumping site accumulated more metals in roots than shoots. Datura innoxia had maximum bioaccumulation of Cr, Calotropis procera of Cd and Ni and Parthenium hysterophorus of Pb in roots. All these plants had Bioacccumulation factor (BAf root )>1 and translocation factor (Tf) <1 for Cd and serve as its phytostabilizer except Calotropis procera which had BAf root >1 and Tf >1 and is identified as a phytoextractor for Cd. Cow-dung amendment alone appeared to be insufficient and additionally the revegetation of natural colonizers is recommended for effective reduction in heavy metal load and improving overall soil health at wasteland. Such eco-restoration may also minimize risks to biodiversity in India.

A study was carried out to evaluate phytodiversity along with the metal accumulation potential of native plants growing in the vicinity of a thermal power plant (TPP). We documented 26 tree species, six shrubs, and 35 herbs. Importance value index (IVI), which measures the extent to which a species dominates in an area, was found highest for Senna siamea (95.7) followed by Tectona grandis (56.5), and Pithecellobium dulce (19.6). Soil was acidic (pH 5.4) in nature with higher concentrations of Al and Fe. The pH of ground water was found acidic while pH of nearby river was found slightly alkaline. Values of PM 2.5 and PM 10 were slightly higher than NAAQS standards for industrial areas. The concentration of metals was found higher in aquatic plants than in terrestrial plants. In general, herbs and shrubs showed more metal accumulation potential than trees. Our results suggest that Senna siamea could be used for revegetation purposes in FA landfills. Further, terrestrial and aquatic plants such as Ageratina adenophora and Stuckenia pectinata could be used for reclamation of Mn, Zn, Al, and Fe from contaminated soils. Hydrilla verticillata (Ni and Mn), Nelumbo nucifera , and Ipomoea aquatica (Cr) can be used for metal removal from contaminated water.

Soil contamination with chromium (Cr) is becoming a primary ecological and health concern, specifically in the Kasur and Sialkot regions of Pakistan. The main objective of the current study was to evaluate the impact of foliar application of zinc oxide nanoparticles (ZnO NPs) (0, 25, 50, 100 mg L -1 ) and Fe NPs (0, 5, 10, 20 mg L -1 ) in red sails lettuce plants grown in Cr-contaminated soil. Our results showed that both ZnO and Fe NPs improved plant growth, and photosynthetic attributes by minimizing oxidative stress in lettuce plants through the stimulation of antioxidant enzyme activities. At ZnO NPs (100 mgL -1 ), dry weights of shoots and roots and fresh weights of shoots and roots were improved by 53%, 58%, 34%, and 45%, respectively, as compared to the respective control plants. The Fe NPs treatment (20 mgL -1 ) increased the dry weight of shoots and the roots and fresh weights of shoots and roots by 53%, 76%, 42%, and 70%, respectively. Application of both NPs reduced the oxidative stress caused by Cr, as evident by the findings of the current study, i.e., at the ZnO NPs (100 mgL -1 ) and Fe NPs (20 mgL -1 ), the EL declined by 32% and 44%, respectively, in comparison with respective control plants. Moreover, Fe and ZnO NPs enhanced the Fe and Zn contents in red sails lettuce plants. Application of ZnO NPs at 100 mg L -1 and Fe NPs at 20 mg L -1 , improved the Zn and Fe contents in plant leaves by 86%, and 68%, respectively, as compared to the control plants. This showed that the exogenous application of these NPs helped in Zn and Fe fortification in plants. At similar of concenteration ZnO NPs, CAT and APX activities were improved by 52% and 53%, respectively. Similarly, the POD contents were improved by 17% and 45% at 5 and 10 mg/L of Fe NPs. Furthermore, ZnO and Fe NPs limited the Cr uptake by plants, and the concentration of Cr in the leaves of lettuce was under the threshold limit. The exogenous application of ZnO NPs (100 mg L -1 ) and Fe NPs (20 mg L -1 ) reduced the Cr uptake in the leaves of red sails lettuce by 57% and 51%, respectively. In conclusion, ZnO and Fe NPs could be used for the improvement of plant growth and biomass as well as nutrient fortification in stressed environments. These findings not only underscore the efficacy of nanoparticle-assisted phytoremediation but also highlight its broader implications for sustainable agriculture and environmental health. However, future studies on other crops with molecular-level investigations are recommended for the validation of the results.

The agro-waste derived valuable products are prime interest for effective management of toxic heavy metals (THMs). The present study investigated the efficacy of biochars (BCs) on immobilization of THMs (Cr, Zn, Pb, Cu, Ni and Cd), bioaccumulation and health risk. Agro-wastes derived BCs including wheat straw biochar (WSB), orange peel biochar (OPB), rice husk biochar (RHB) and their composite biochar (CB) were applied in industrial contaminated soil (ICS) at 1% and 3% amendments rates. All the BCs significantly decreased the bioavailable THMs and significantly ( p  < 0.001) reduced bioaccumulation at 3% application with highest efficiency for CB followed by OPB, WSB and RHB as compared to control treatment. The bioaccumulation factor (BAF), concentration index (CI) and ecological risk were decreased with all BCs. The hazard quotient (HQ) and hazard index (HI) of all THMs were <1, except Cd, while carcer risk (CR) and total cancer risk index (TCRI) were decreased through all BCs. The overall results depicted that CB at 3% application rate showed higher efficacy to reduce significantly ( p  < 0.001) the THMs uptake and reduced health risk. Hence, the present study suggests that the composite of BCs prepared from agro-wastes is eco-friendly amendment to reduce THMs in ICS and minimize its subsequent uptake in vegetables.

The rupture of the Fundão dam (Brazil) spread tailings contaminated with sodium and ether-amine into the Doce River Basin. Aiming at rehabilitating a contaminated riparian site, phytoremediation with native species of the Atlantic Forest was performed under four treatments: ES-1: physical remediation (sediment scraping) + chemical remediation (organic matter) + bioremediation (double inoculation with the arbuscular mycorrhizal fungus (AMF) Rhizophagus irregularis and the plant growth-promoting bacteria Bacillus subtilis ); ES-2: chemical remediation + bioremediation; ES-3: physical remediation + chemical remediation; ES-4: chemical remediation. Ether-amine and sodium contents, plant growth and, soil quality parameters were compared among treatments and relative to preserved and degraded sites. Two years after planting, the outstanding plant growth was attributed to the phytoremediation of ether-amine and ammonium, followed by a significant increase in soil microbial biomass (Phospholipid fatty acids-PLFAs), particularly the Gram + bacteria and total fungi but not AMF, whose response was independent of the inoculation. While sodium and ether-amine declined, soil K, P, NO 3- contents, dehydrogenase and acid phosphatase activities, cation exchange capacity (CEC) and soil aggregation increased, especially in ES-1. Thus, such remediation procedures are recommended for the restoration of riparian areas affected by the Fundão tailings, ultimately improving sediment fertility, aggregation and stabilization.

This research examined the impact of heavy metals, including Cd, Pb, and Zn, on chlorophyll content and lamina cell structure in Bryum coronatum . After exposure to varying metal concentrations (0.015, 0.065, 0.250, 1, and 4 mg/L), chlorophyll content, chloroplast numbers, lamina cell change, and metal accumulation were investigated. Chlorophyll content was assessed using spectrophotometry, whereas chloroplast numbers and lamina cell changes were examined under a light microscope. Metal accumulation was quantified through ICP-MS. The findings revealed that Cd notably reduced chlorophyll a content, while Pb and Zn showed minimal influence. Cd and Pb exposure decreased the number of chloroplasts in lamina cells, with no impact from Zn. The moss's capacity to absorb metals increased with higher exposure levels, indicating its potential as a biomonitor for heavy metal pollution. Cell mortality occurred in response to Cd and Pb, primarily in the median and apical lamina regions, while Zn had no effect. This study sheds light on heavy metal toxicity in B. coronatum , underscoring its significance for environmental monitoring. Further research on the mechanisms and consequences of heavy metal toxicity in bryophytes is essential for a comprehensive understanding of this critical issue.

There are scarce data regarding the effects of soil amendments on biophysicochemical responses of plants at the early stages of growth/germination. This study critically compares the effects of ethylene-diamine-tetra-acetic-acid (EDTA) and calcium (Ca) on biophysicochemical responses of germinating pea seedlings under varied arsenic levels (As, 25, 125, 250 µM). Arsenic alone enhanced hydrogen peroxide (H 2 O 2 ) level in pea roots (176%) and shoot (89%), which significantly reduced seed germination percentage, pigment contents, and growth parameters. Presence of EDTA and Ca in growth culture minimized the toxic effects of As on pea seedlings, EDTA being more pertinent than Ca. Both the amendments decreased H 2 O 2 levels in pea tissues (16% in shoot and 13% in roots by EDTA, and 7% by Ca in shoot), and maintained seed germination, pigment contents, and growth parameters of peas close to those of the control treatment. The effects of all As-treatments were more pronounced in the pea roots than in the shoot. The presence of organic and inorganic amendments can play a useful role in alleviating As toxicity at the early stages of pea growth. The scarcity of data demands comparing plant biophysicochemical responses at different stages of plant growth (germinating vs mature) in future studies.

Rhizospheric microbial communities improve the effectiveness of hyperaccumulators in the phytoremediation of heavy metals. However, limited access to tailing dams and inadequate assessment of plants' phytoremediation potential limit the characterization of native accumulators, hindering the effectiveness of local remediation efforts. This study evaluates the heavy metal sequestration potentials of Pennisetum purpureum , Leucaena leucocephala, and Pteris vittata and their associated rhizospheric microbial communities at the Marlu and Pompora tailing dams in Ghana. The results indicate shoot hyperaccumulation of Cd (334.5 ± 6.3 mg/kg) and Fe (10,647.0 ± 12.6 mg/kg) in P. purpureum and L. leucocephala , respectively. Analysis of rhizospheric bacterial communities revealed the impact of heavy metal contamination on bacterial community composition, associating Fe and Cd hyperaccumulation with Bacillus , Arthrobacter , and Sphingomonas species. This study reports the hyperaccumulation potentials of L. leucocephala and P. purpureum enhanced by associated rhizosphere bacterial communities, suggesting their potential application as an environmentally friendly remediation process of heavy metals contaminated lands.

The purpose of this study was to evaluate the potential of microbial-enhanced Brassica oleracea for the phytoremediation of seleniferous soils. The effect of selenite (Se(IV)) and selenate (Se(VI)) on B. oleracea (1-100 mg.L -1 ) was examined through germination (7 d) and pot (30 d) trials. Microbial analysis was conducted to verify the toxic effect of various Se concentrations (1-500 mg.L -1 ) on Rhodococcus opacus PD360, and to determine if it exhibits plant growth promoter traits. R. opacus PD630 was found to tolerate high concentrations of both Se(IV) and Se(VI), above 100 mg.L -1 . R. opacus PD630 reduced Se(IV) and Se(VI) over 7 days, with a Se conversion efficiency between 60 and 80%. Germination results indicated lower concentrations (0-10 mg.L -1 ) of Se(IV) and Se(VI) gave a higher shoot length (> 4 cm). B. oleracea accumulated 600-1,000 mg.kg -1  dry weight (DW) of Se(IV) and Se(VI), making it a secondary accumulator of Se. Moreover, seeds inoculated with R. opacus PD360 showed increased Se uptake (up to 1,200 mg Se.kg -1 DW). In addition, bioconcentration and translocation factors were greater than one. The results indicate a synergistic effect between R. opacus PD630 and B. oleracea for Se phytoextraction from polluted soils.

In this study, wild barley ( Hordeum brevisubulatum ) infected (E+) and uninfected (E-) by Epichloë bromicola were used for hydroponic experiments during the seedling stage. Various attributes, such as the effect of fungal endophyte on the growth and development of wild barley, the absorption of cadmium (Cd) and mineral elements (Ca, Mg, Fe, Mn, Cu, Zn), subcellular distribution, and chemical forms were investigated under CdCl 2 stress. The results showed that the fungal endophy significantly reduced the Ca content and percentage of plant roots under Cd stress. The Fe and Mn content of roots, the mineral element content of soluble fractions, and the stems in the pectin acid or protein-chelated state increased significantly in response to fungal endophy. Epichloë endophyte helped Cd 2+ to enter into plants; and reduced the positive correlation of Ca-Fe and Ca-Mn in roots. In addition, it also decreased the correlation of soluble components Cd-Cu, Cd-Ca, Cd-Mg in roots, and the negative correlation between pectin acid or protein-chelated Cd in stems and mineral elements, to increase the absorbance of host for mineral elements. In conclusion, fungal endophy regulated the concentration and distribution of mineral elements, while storing more Cd 2+ to resist the damage caused by Cd stress. The study could provide a ground for revealing the Cd tolerance mechanism of endophytic fungal symbionts.

Cadmium is one of the most harmful heavy metals that harm agricultural products. Evaluating microRNAs expression is a new and accurate method to study plant response in various environmental conditions. So this study aimed to evaluate the contribution of two symbiotic fungi in improving flax tolerance in a Cd-polluted soil using microRNAs and their target gene expression. A factorial pot experiment in a completely randomized design was conducted with different levels of Cd (0, 20, and 40 mg kg -1 ) on non-inoculated and inoculated flax with Claroideoglomus etunicatum and Serendipita indica . The results presented that increasing Cd levels caused a constant decline of alkaline phosphatase of soil (from 243 to 210 and 153 μg PNP g -1 h -1 ), respectively, from control (Cd0) to 20 and 40 mg Cd kg -1 . However, the inoculation of flax with fungi significantly enhanced these properties. A negative correlation was observed between the expression level of microRNA 167 and microRNA 398 with their corresponding target genes, auxin response factor 8 and superoxide dismutase zinc/copper 1, respectively. The expression level of both microRNAs and their targets indicated that the inoculation with symbiont fungi could diminish Cd stress and enhance the growth of flax.

Little information is available on the influence of the compound use of intercropping (IN) and arbuscular mycorrhizal fungus (AMF) on Cd accumulation and the expression of Cd transporter genes in two intercropped plants. A pot experiment was conducted to study the influences of IN and AMF- Glomus versiforme on growth and Cd uptake of two intercropped plants-maize and Cd hyperaccumulator Sphagneticola calendulacea , and the expression of Cd transporter genes in maize in Cd-polluted soils. IN, AMF and combined treatments of IN and AMF (IN + AMF) obviously improved biomass, photosynthesis and total antioxidant capacities of two plants. Moreover, single and compound treatments of IN and AMF evidently reduced Cd contents in maize, and the greatest decreases appeared in the compound treatment. However, Cd contents of S. calendulacea in IN, AMF and IN + AMF groups were notably improved. Furthermore, the single and compound treatments of IN and AMF significantly downregulated the expression levels of Nramp1, HMA1 , ABCC1 and ABCC10 in roots and leaves, and the largest decreases were observed in the combined treatment. Our work first revealed that the combined use of IN and AMF appeared to have a synergistic effect on decreasing Cd content by downregulating the expression of Cd transporter genes in maize.

Cadmium (Cd) is the most toxic element which may cause serious consequences to microbial communities, animals, and plants. The use of green technologies like phytoremediation employs plants with high biomass and metal tolerance to extract toxic metals from their rooting zones. In the present work, Hydrocotyle umbellata was exposed to five Cd concentrations (2, 4, 6, 8, and 10 µmol) in triplicates to judge its phytoextraction ability. Effects of metal exposure on chlorophyll (Chl), bio-concentration factor (BCF), translocation factor (TF), and electrolyte leakage (EL) were analyzed after 10 days of treatment. Metal-responding genes were also observed through transcriptomic analysis. Roots were the primary organs for cadmium accumulation followed by stolon and leaves. There was an increase in EL. Plants showed various symptoms under increasing metal stress namely, chlorosis, browning of the leaf margins, burn-like areas on the leaves, and stunted growth, suggesting a positive relationship between EL, and programmed cell death (PCD). Metal-responsive genes, including glutathione, expansin, and cystatin were equally expressed. The phytoextraction capacity and adaptability of H. umbellata L. against Cd metal stress was also demonstrated by BCF more than 1 and TF less than 1.

Soil contamination by toxic metals threatens global public health, highlighting the need for cost-effective and ecologically sound site remediation. In this study, we assessed phytoremediation of Hg-contaminated soils by Emilia fosbergii Nicolson (Asteraceae). Pot experiment was conducted using a substrate of sand and vermiculite (1:1 volume ratio), treatments consisted of five Hg concentrations (0, 1, 3, 5, and 7 mg kg -1 ). Metal transfer rates were calculated, including accumulation (BAF), translocation (TF) and bioconcentration (BCF) factors. E. fosbergii roots exhibited greater Hg accumulation than other tissues, but biomass production and plant health were not significantly affected at the concentrations tested, as indicated by elongation factors and tolerance index. The results revealed BAF values between 2.18 and 7.14, TF values ranged between 0.15 and 0.52, and the BCF index varied between 8.97 and 26.58. Treatments with Hg content of 5 mg kg -1 and 7 mg kg -1 recorded the highest total Hg concentrations of 66 mg kg -1 and 65.53 mg kg -1 (roots), and 9.18 mg kg -1 and 33.88 mg kg -1 (aerial), respectively. E. fosbergii demonstrated promise for Hg phytoremediation due to its high accumulation capacity, indicated by regular TF and high BCF and BAF indexes, thus classifying it as a high Hg accumulator.

In this study, the phytoremediation efficiency of Arabidopsis halleri L. in response to mechanical injury were compared between those irrigated with magnetized water and those irrigated with normal water. Under normal irrigation treatment, wounding stress increased malondialdehyde (MDA) concentrations and hydrogen peroxide (H 2 O 2 ) levels in A. halleri leaves significantly, by 46.7-86.1% and 39.4-77.4%, respectively, relative to those in the intact tissues. In addition, wounding stresses decreased the content of Cd in leaves by 26.8-52.2%, relative to the control, indicating that oxidative damage in plant tissues was induced by mechanical injury, rather than Cd accumulation. There were no significant differences in MDA and H 2 O 2 between A. halleri irrigated with magnetized water and with normal water under wounding conditions; however, the activities of catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) in the leaves of plants treated with magnetized water were significantly increased by 25.1-56.7%, 47.3-183.6%, and 44.2-109.4%, respectively. Notably, under the magnetic field, the phytoremediation effect of 30% wounded A. halleri nearly returned to normal levels. We find that irrigation with magnetized water is an economical pathway to improve the tolerance of A. halleri to inevitable mechanical injury and may recover its phytoremediation effect.

Based on the growth-promoting effect of plant growth promoting bacteria on plants and the mobilization of Cd by citric acid, an experiment was designed in which the combined treatment of Bacillus megaterium and citric acid promoted ryegrass to repair Cd-contaminated soil. This study aimed to evaluate the effects of different treatments on the antioxidant enzyme activity, photosynthesis intensity, Cd accumulation, and rhizosphere cadmium migration under cadmium contamination conditions. And the soil morphology and structure changes were studied by infrared spectroscopy FourierTransformInfrared(FT-IR) and scanning electron microscope Energy Dispersive Spectrometer(SEM-EDS) before and after different treatments. The results show that the combined treatment of Bacillus megaterium and citric acid significantly improved the oxidative stress defense and plant photosynthesis and increased of rye biomass. rye biomass 1.28 times higher than CK treatment. Joint treatment significantly increased the amount of shoot accumulation of Cd, 2.31 times higher than CK treatment, increased the migration and accumulation of cadmium. FTIR and SEM-EDS also showed that the organic constituents such as O-H, C-O and C-N in soils as a major mechanism for mobilization of the heavy metal Cd. Thus, the combined treatment of Bacillus megaterium and citric acid can promote plant growth, improve the damage to ryegrass caused by single organic acid addition, and improve the plant extraction efficiency, which is a feasible way to repair Cd-contaminated soil through activated extraction system.

Potential trace elements pollution in cities poses a threat to the environment and human health. Bio-availability affects toxicity levels of potential trace elementss on organisms. This study focused on exploring the relationship between soil, plant, and atmospheric dust pollution in Urumqi, a typical city in western China. It aims to help reduce pollution and protect residents' health. The following conclusions were drawn: 1) potential trace elementss like Cr, Pb, As, and Ni are more prevalent in atmospheric dust and soil than in plants. Chromium was in the first group, Cadmium and Mercury were in the second, and Plumb, Arsenic, and Nickel were in the third. Atmospheric dust and soil exhibit a significantly higher heavy metal content than plants. For example, The atmospheric dust summary Chromium content was up to 88 mg/kg. 2) Soil, atmospheric dust, and plants have the highest amount of residual form. Residual form had the highest percentage average of 53.3%, whereas Organic matter bound form had the lowest percentage of just 7.7%. The plants contained less residual heavy metal than the soil and atmospheric dust. 3) The correlation coefficient between the carbonated form content of Cd of soil and atmospheric dust is 0.95, which is closely related. Other potential trace elements show similar correlations in their bio-available contents in soil, plants, and atmospheric dust. This study suggests that in urban area, the focus should be on converting potential trace elements into residual form instead of increasing plants' absorption of potential trace elements.

Polycyclic aromatic hydrocarbons (PAHs) are phytotoxic, which can limit their phytoremediation. When the ability of plants to phytoremediation PAHs is compromised, the application of plant growth regulators can enhance the growth of the plants. This study aimed to determine the best plant growth regulator (1-naphthalene acetic acid, 6-benzyladenine, or thidiazuron) to enhance the phytoremediation ability of sweet grass ( Pennisetum purpureum cv. Mahasarakham) when grown in weather PAH-contaminated soil. In a greenhouse study, 0.01 mg/l thidiazuron resulted in the highest growth of sweet grass when compared to the other tested plant growth regulators (dry shoot weight 24.11 ± 1.28 g and dry root weight 0.70 ± 0.02 g). Sweet grass was grown in soil contaminated with PAH, which demonstrated the toxicity to sweet grass by reducing the total chlorophyll (1.01 µg/g fresh weight) and carotenoid (0.28 µg/g fresh weight) contents with proline increased (6.63 µg/g fresh weight). Meanwhile, total chlorophyll, carotenoid, and proline content in leaves of sweet grass grown in non-contaminated soil were 1.68, 0.44, and 5.23 µg/g fresh weight, respectively. When sweet grass was used to phytoremediate PAHs, there were reductions in acenaphthylene (4.69 ± 0.50%), acenaphthene (10.69 ± 1.47%), and phenanthrene (3.61 ± 0.07%), which compared to levels of over 30% in non-planted soil. For the three PAHs, the bioconcentration factors were 1.6 to 2.4, but the translocation factors were below 1, showing limited movement to the aerial parts of the plant, thereby suggesting that the main mechanism is rhizoremediation. Sweet grass is an excellent candidate for PAH remediation, especially when thidiazuron is applied to relieve plant stress.

Low remediation efficiency due to low bioavailability is a primary restrictive factor for phytoremediation applications. Specifically, this investigation examines whether Suaeda heteroptera Kitagawa ( S. heteroptera ) can be used in combination with β-cyclodextrin (β-CD) to remediate contaminated site. The study was conducted on the growth response of S. heteroptera , bioavailability and dissipation of petroleum hydrocarbons (PHs) in soil under the influence of β-CD Our preliminary studies confirmed that β-CD is effective in increasing the biomass and height of plants. The presence of β-CD could dramatically elevate polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in S. heteroptera . Moreover, a remarkable positive correlation between PHs levels in roots with the dosage of β-CD and a negative correlation between the PHs levels in roots with KOW of PHs have been observed. The dissipation of n-alkanes was estimated to be 38.73-62.27%, and the dissipation of PAHs was 36.59-60.10%. In addition, the dissipation behavior of n-alkanes and PAHs was well agreement with the first-order kinetic model. These results display that applying β-CD accelerated the desorption process of PHs from soil and promoted the absorption process of PHs onto the root epidermis. The enhancement of phytoremediation was achieved by increasing the bioavailability of PHs.

In the present study, experiments were conducted to assess the influence of nanoscale sulfur in the microbial community structure of metallophytes in Hg-contaminated rhizosphere soil for planting rapeseed. The results showed that the richness and diversity of the rhizobacteria community decreased significantly under Hg stress, but increased slightly after SNPs addition, with a reduction in the loss of Hg-sensitive microorganisms. Moreover, all changes in the relative abundances of the top ten phyla influenced by Hg treatment were reverted when subjected to Hg + SNPs treatment, except for Myxococcota and Bacteroidota. Similarly, the top five genera, whose relative abundance decreased the most under Hg alone compared to CK, increased by 19.05%-54.66% under Hg + SNPs treatment compared with Hg alone. Furthermore, the relative abundance of Sphingomonas , as one of the dominant genera for both CK and Hg + SNPs treatment, was actively correlated with plant growth. Rhizobacteria, like Pedobacter and Massilia , were significantly decreased under Hg + SNPs and were positively linked to Hg accumulation in plants. This study suggested that SNPs could create a healthier soil microecological environment by reversing the effect of Hg on the relative abundance of microorganisms, thereby assisting microorganisms to remediate heavy metal-contaminated soil and reduce the stress of heavy metals on plants.

The effects of rootstocks tomato ( Solanum lycopersicum L.), eggplant ( Solanum melongena L.), and nightshade ( Solanum nigrum L.) grafting on the growth and selenium (Se) accumulation of Cyphomandra betacea Sendt. seedlings were studied to identify the most suitable rootstock for increasing Se uptake of fruit trees grown in Se-contaminated soil. The rootstocks of tomato, eggplant, and nightshade grafting increased the scion biomass of C. betacea seedlings by 146.1%, 23.2%, and 94.5%, respectively, compared with the un-grafted seedlings. Moreover, tomato, eggplant, and nightshade rootstocks grafting increased the photosynthesis, superoxide dismutase activity, and peroxidase activity, while reducing the catalase activity and soluble protein content of C. betacea seedlings. Although all three rootstocks grafting decreased Se contents in rootstock roots and stems, only nightshade rootstock grafting increased Se content in the scions of C. betacea seedlings. Notably, root biomass, catalase activity, soluble protein content, rootstock root Se content, and rootstock stem Se content were closely related to the scion Se content. These findings suggest that only grafting onto nightshade rootstock significantly enhances Se uptake in C. betacea , whereas tomato and eggplant rootstocks grafting have no effect on Se uptake.

Urease-producing bacteria (UPB) are widely present in soil and play an important role in soil ecosystems. In this study, 65 UPB strains were isolated from cadmium (Cd)-polluted soil around a lead-zinc mine in Yunnan Province, China. The Cd tolerance, removal of Cd from aqueous solution, production of indoleacetic acid (IAA) and plant growth-promoting effects of these materials were investigated. The results indicate that among the 65 UPB strains, four strains with IAA-producing ability were screened and identified as Bacillus thuringiensis W6-11, B. cereus C7-4, Serratia marcescens W11-10, and S. marcescens C5-6. Among the four strains, B. cereus C7-4 had the highest Cd tolerance, median effect concentration (EC 50 ) of 59.94 mg/L. Under Cd 5 mg/L, S. marcescens C5-6 had the highest Cd removal from aqueous solution, up to 69.83%. Under Cd 25 mg/kg, inoculation with B. cereus C7-4 significantly promoted maize growth in a sand pot by increasing the root volume, root surface area, and number of root branches by 22%, 29%, and 20%, respectively, and plant height and biomass by 16% and 36%, respectively, and significantly increasing Cd uptake in the maize roots. Therefore, UPB is a potential resource for enhancing plant adaptability to Cd stress in plants with Cd-polluted habitats.

Mercury (Hg) pollution in Ghana through mining has become a serious environmental challenge. This study investigates the potential of Cirsium arvense to photostabilize Hg using electrokinetic current with or without an iodide solution in gold mine tailings heavily contaminated through mining activities in southern Ghana. An initial Hg concentration of 9.60 mg/kg using cold vapor atomic absorption spectrometry (CVAAS) was determined. The biological absorption coefficient, bioconcentration factor, and translocation factor of Hg have been presented. Cirsium arvense therefore had a higher bioconcentration factor (BCF) of 2.6-5.15 mg/kg, and a transfer factor (TF) of 0.24-0.36 indicating a higher efficiency for phytostabilization. Both the rate and time of extractions of Hg from the tailings by Cirsium arvense are efficiently improved in the combined electric current and iodide treatment. Plant and electric current combined treatment and plant and iodide combined treatment had only 60 and 50% phytostabilization rates, respectively. The combined plant, iodide, and electric current treatment has proven to be superior with about >90% Hg removal rate. Therefore, the combined plant, iodide, and electric current treatment resulted in a higher Hg removal efficiency by Cirsium arvense in a shorter period due to higher solubilization rate and electromigration effects on Hg species.

Toxic metals cause risks to the ecological environment. Typha latifolia L. is a good candidate to clean potentially toxic metals contaminated water or soil. However, limited research investigated the impact of environmental factors ( e.g., pH, soil substrate, flood duration) on metal accumulations in cattails. In this study, cattails were cultured in soils flooded with artificial wastewater with varying pH (5, 7 or 9) and different levels of Cr, Cd and Zn for four weeks to investigate the interactions between environmental conditions and metal uptake in cattails. The metal content in biomass were measured by an inductively coupled plasma-optical emission spectrometer., More Zn (>10,000 mg/kg dry biomass) entered plants compared to Cd and Cr (<1,000 mg/kg dry biomass). Approximately 80% of Zn from solutions with 50 mg/L Cd, 25 mg/L Cr, 250 mg/L Zn were removed by cattails. Most Cd and Cr were sorbed onto soils. Cattails exhibited relatively consistent performance in removing metals from wastewater with initial pH of 5, 7 or 9. The pH of all the solutions ended close to neutral after 4 weeks. More research is needed to further understand the influence of environmental conditions on metal uptakes in plants to improve phytoremediation efficiency.

This study unveiled the cadmium phytoremediation potential and its augmentation using 6-Benzylaminopurine in Strobilanthes alternata . Cadmium stress was provided by applying 250 mg/kg cadmium chloride in soil and 25 ppm of 6-BAP (25 ml) was administered to the plants as foliar spray. The results revealed high bioconcentration factor (BCF) (18.82 ± 0.54) and low translocation factor (TF) values (0.055 ± 0.002) for the plant based on which we strongly recommend S. alternata as a promising candidate for Cd phytoremediation. The phytostabilization potential of the plant was further enhanced by applying 6-BAP, which augmented its BCF to 22.09 ± 0.64 and reduced the TF to 0.038 ± 0.001. Cd toxicity caused a reduction of plant growth parameters, root volume, adaxial-abaxial stomatal indices, relative water content, tolerance index, moisture content, membrane stability index, and xylem vessel diameter in S. alternata . However, Cd + 6-BAP treated plants exhibited an increase of the same compared to Cd-treated plants. FTIR analysis of Cd + 6-BAP treated plants revealed increased deposition of hemicellulose, causing enhanced retention of Cd in the root xylem walls, which is largely responsible for increased phytostabilization of Cd. Therefore, 6-BAP application in S. alternata can be exploited to restore Cd-contaminated areas effectively.

One of the most important oil crops in the world, sunflower ( Helianthus annuus L.), is recognized to help in soil phytoremediation. Heavy metal (HM) contamination is one of the most abiotic challenges that may affect the growth and productivity of such an important crop plant. We studied the influence of HM-contaminated soils on metal homeostasis and the potential hypertolerance mechanisms in two sunflower Egyptian cultivars (V120 and S53). Both cultivars accumulated significantly higher cadmium concentrations in their roots compared to their shoots during Cd and Zn/Cd treatments. Higher root concentrations of 121 mg g -1  dry weight (DW) and 125 mg g -1 DW were measured in V120 plants compared to relatively lower values of 111 mg g -1 DW and 105 mg g -1 DW in the roots of S53 plants, respectively. Cadmium contamination significantly upregulated the expression of heavy metal ATPases ( HaHMA4 ) in the shoots of V120 plants. On the other hand, their roots displayed a notable expression of HaHMA3 . This study indicates that V120 plants accumulated and sequestered Cd in their roots. Therefore, it is advised to cultivate the V120 cultivar in areas contaminated with heavy metals as it is a promising Cd phytoremediator.

Bauxite residue (BR) is a large volume by-product generated during bauxite smelting process and metal pollution problem is becoming increasingly prominent in residue areas. Accumulation and transfer of metals in six vascular plants were analyzed and soil environment was evaluated. Results found levels of Al (2,110-26,280 mg kg -1 ), Fe (990 to 9,880 mg kg -1 ), Ca (8,020 to 49,250 mg kg -1 ), Mg (2,060 to 17,190 mg kg -1 ), K (16,840 to 39,670 mg kg -1 ), and Ti (80 to 1,240 mg kg -1 ) in plants. Metal concentrations in soils exceeded background levels. Bioconcentration factor (BCF) found that Al, Fe, and Ti in plants (roots, stems, and leaves) were relatively depleted (BCF <1). Transfer factor (TF) of Al, Fe, Ca, K, and Ti in plants was distinctly higher than 1 and mainly concentrated in stems and leaves. Pollution indices revealed that soil environment was at moderated to serious contaminated risk. Principal components analysis (PCA) showed that Artemisia caruifolia Buch. and Siegesbeckia orientalis L. plants had a good ability to absorb Al and Fe, which can be used as biological indicators and restoration materials.

The study was conducted to evaluate the phytoremediation response of Arundo donax and vetiver grasses irrigated by different levels (0%, 10%, 25%, 50%, 75%, and 100%) of treated tannery wastewater. After 60 days, matured plants were harvested, sorted into root, leaf, stem and shoot, dried and digested using standard procedures and analyzed for Cr(VI) and total Cr using atomic absorption and UV-Visible spectrophotometer, respectively. Corresponding results revealed height growth of Arundo donax and vetiver grasses was greatly affected by the irrigation level of tannery wastewater. Roots of vetiver grasses accumulate the highest amount of Cr(VI) (2.76 mg/kg) compared to the shoots Cr(VI) 1.72 mg/kg. Lowering concentration of tannery wastewater used for irrigation to 10% boosted the accumulation capacity (3.99 mg/kg) of the root of Arundo donax grasses for Cr(VI). The translocation values (TF > 1) demonstrated favourability of Arundo donax grasses for phytoextraction of Cr(VI) to plant tissues above ground level. However, the bioaccumulation values (BAF > 1) of the root of vetiver grasses proved suitability for the phytostabilisation of Cr(VI). Arundo donax and vetiver grasses have demonstrated a substantial reduction in Cr contamination of soils from tanneries, and therefore, phytoremediation is potentially feasible for the decontamination of Cr-polluted environments.

Natural amino acids (NAA) have been rarely investigated as chelators, despite their ability to chelate heavy metals (HMs). In the present research, the effects of extracted natural amino acids, as a natural and environmentally friendly chelate agent and the inoculation of Pseudomonas fluorescens ( PF ) and Micrococcus yunnanensis ( MY ) bacteria were investigated on some responses of quinoa in a soil polluted with Pb, Ni, Cd, and Zn. Inoculation of PGPR bacteria enhanced plant growth and phytoremediation efficiency. Pb and Cd were higher in quinoa roots, while Ni and Zn were higher in the shoots. The highest efficiencies were observed with NAA treatment and simultaneous inoculation of PF and MY bacteria for Ni, Cd, Pb, and Zn. The highest values of phytoremediation efficiency and uptake efficiency of Ni, Cd, Pb, and Zn were 21.28, 19.11, 14.96 and 18.99 μg g-1, and 31.52, 60.78, 51.89, and 25.33 μg g-1, respectively. Results of present study well demonstrated NAA extracted from blood powder acted as strong chelate agent due to their diversity in size, solubilizing ability, abundant functional groups, and potential in the formation of stable complexes with Ni, Cd, Pb, and Zn, increasing metal availability in soil and improving phytoremediation efficiency in quinoa.

The present study illustrated that Salix alba can accumulate high level of Pb and Cd in different plant parts, with maximum accumulation in roots followed by stem and leaves in the order Cd > Pb > Cd + Pb. The phytoremediation evaluation factors such as bioconcentration factor (BCF) and translocation factor (TF) was higher for Cd over Pb in all plant parts, further the BCF for both Pb and Cd was maximum in root (BCF > 1) followed by stem and leaves. Higher accumulation of Cd over the Pb was observed inside the plant tissues due to Cd mimics with other elements and gets transported through respective transporters. The combined treatment of Pb and Cd affected the bioaccumulation at every treatment level suggesting the negative effect among both elements. Higher survival rate (>85%) was recorded up to 200mgPb/kg and 15mgCd/kg, while further increase in metal concentration reduced the plant efficiency to remediate contaminated soils, hence results in declined survival rate. The FTIR analysis revealed that Pb and Cd accumulation in plants induced changes in carboxy, amino, hydroxyl and phosphate groups that ultimately caused alteration in physiological and biochemical processes of plant and thus provided an insight to the interaction, binding and accumulation of heavy metals.

Bioaugmentation of soils can increase the mobilization of metal(loid)s from the soil-bearing phases. However, once desorbed, these metal(loid)s are mostly complexed to the dissolved organic matter (DOM) in the soil solution, which can restrict their availability to plants (roots mainly taking up the free forms) and then the phytoextraction performances. Firstly the main drivers influencing phytoextraction are reminded, then the review focuses on the DOM role. After having reminding the origin, the chemical structure and the lability of DOM, the pool of stable DOM (the most abundant in the soil) most involved in the complexation of metal(loid)s is addressed in particular by focusing on carboxylic and/or phenolic groups and factors controlling metal(loid) complexation with DOM. Finally, this review addresses the ability of microorganisms to degrade metal(loid)-DOM complexes as an additional lever for increasing the pool of free metal(loid) ions, and then phytoextraction performances, and details the origin of microorganisms and how they are selected. The development of innovative processes including the use of these DOM-degrading microorganisms is proposed in perspectives.

Chromium (Cr) contamination of soil has substantially deteriorated soil health and has interfered with sustainable agricultural production worldwide and therefore, its remediation is inevitable. Inoculation of plant growth promoting rhizobacteria (PGPR) in association with nanotechnology has exerted broad based impacts in agriculture, and there is an urgent need to exploit their synergism in contaminated soils. Here, we investigated the effect of co-application of Cr-tolerant " Pseudomonas aeruginosa CKQ9" strain and nano zerovalent iron (nZVI) in improving the phytoremediation potential of aloe vera ( Aloe barbadensis L.) under Cr contamination. Soil was contaminated by using potassium dichromate (K 2 Cr 2 O 7 ) salt and 15 mg kg -1 contamination level in soil was maintained via spiking and exposure to Cr lasted throughout the duration of the experiment (120 days). We observed that the co-application alleviated the adverse impacts of Cr on aloe vera, and improved various plant attributes such as plant height, root area, number of leaves and gel contents by 51, 137, 67 and 49% respectively as compared to control treatment under Cr contamination. Similarly, significant boost in the activities of various antioxidants including catalase (124%), superoxide dismutase (87%), ascorbate peroxidase (36%), peroxidase (89%) and proline (34%) was pragmatic under contaminated soil conditions. In terms of soil Cr concentration and its plant uptake, co-application of P. aeruginosa and nZVI also reduced available Cr concentration in soil (50%), roots (77%) and leaves (84%), while simultaneously increasing the relative production index by 225% than un-inoculated control. Hence, integrating PGPR with nZVI can be an effective strategy for enhancing the phytoremediation potential of aloe vera.

Many contaminated tailings throughout the world cause environmental and human-health related problems due to air and water drift. Tailing phytostabilization is a promising solution, but only certain plant species may tolerate and grow in these contaminated areas. We analyzed the chemical properties of a vegetated and unvegetated area in a tailing site in Central Chile. In addition, in the vegetated area we analyzed the metals content of roots, stems, and foliage in 41-years old plantations of Pinus radiata , Acacia dealbata , and Eucalyptus globulus (the only three species that survived from a total of 34 species planted), and determined height (H), and diameter at breast height (DBH). The results indicated that, except for pH, Se, Pb, and organic matter, all components (nutrients and metals) were two- to three- fold lower in the vegetated tailing compared to that of the unvegetated tailing. The analysis of plant tissues indicated that Cu was higher in the roots of P. radiata (2,073 mg kg -1 ) and lower in the stems of the same species (4.1 mg kg -1 ). However, the ability to take up and transport Cu to the shoots was higher in A. dealbata and lower in P. radiata (bioaccumulation factor of 0.19 and 0.06, respectively).

Persistent crude oil contamination poses a significant environmental challenge. In this study, the efficacy of Vigna unguiculata (L.) and associated rhizospheric microorganisms in remediating crude oil-contaminated soil within a microcosm setting was investigated. A randomized block design was employed, and soil samples were subjected to varying degrees of contamination: 0% (UR), 2.5% (CR2), 5.0% (CR5), 7.5% (CR7), and 10.0% (CR10) w/w crude oil. The investigation aimed to assess the potential of Vigna unguiculata (L.) in mitigating crude oil contamination across these defined contamination gradients. The plant growth and crude oil removal were monitored concurrently post-emergence. Plant emergence and growth were significantly affected due to contamination, especially among plants in CR5 and CR10. The bacterial population was higher in the rhizosphere, and the treatments with lower hydrocarbon contamination. It was shown that plant density encouraged the growth of bacterial communities. Significant reduction in soil TPH was observed in CR2 (76.61%) and CR7 (65.88%). There was a strong correlation between plant growth and oil-utilizing bacterial population (r 2 = 0.966) and plant growth and hydrocarbon reduction (r 2  = 0.956), signifying the role of plant-bacterial synergy. Saturate fractions (C30 - C32) were significantly degraded to lower molecular weight compounds (C11 - C14). Except in CR5 and CR10, the remediation within the cowpea rhizosphere was effective even at regulatory standards. Understanding the rhizosphere ecological dynamics would further highlight the role the bacteria played; hence, it is recommended.

The studies showed the effectiveness of green-synthesized SiO 2 NPs in mitigating the toxicity of Arsenic. Density Functional Theory (DFT) is a computational method used to determine electronic structure, energy gap, and toxicity prediction. Experimentally, silicon nanoparticles of 0 (S0) and 100% v/v (S100) were applied to the surface of the soil. 150 mL of Arsenic trioxide was applied twice at a rate of 0 (As0) and 3.2 g/mL (As3.2) at an interval of three weeks. Green synthesized SiO2NPs possessed a higher chemical potential (µ) and electrophilicity index; consequently, charges could be transferred and easily polarized. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels of the green synthesized SiO 2 NPs enable them to donate electrons and complex with arsenic, reducing their bioavailability and toxicity. Evidence from the studies further showed that SiO 2 NPs had buffered the soil acidity and electric conductivity, posing a high binding site and reactivity with exchangeable cations and micronutrients due to their smaller energy gap. Furthermore, the catalytic activities of the soil enzymes dehydrogenase (DHA) and peroxidase (POD) were greatly increased, which enhanced the electrostatic interaction between the SiO 2 NPs and As.

Sulfonamides (SAs) in agricultural soils can be degraded in rhizosphere, but can also be taken up by vegetables, which thereby poses human health and ecological risks. A glasshouse experiment was conducted using multi-interlayer rhizoboxes to investigate the fate of three SAs in rape and hot pepper rhizosphere soil systems to examine the relationship between the accumulation and their physicochemical processes. SAs mainly entered pepper shoots in which the accumulation ranged from 0.40 to 30.64 mg kg -1 , while SAs were found at high levels in rape roots ranged from 3.01 to 16.62 mg kg -1 . The BCF pepper shoot exhibited a strong positive linear relationship with log D ow , while such relationship was not observed between other bioconcentration factors (BCFs) and log D ow . Other than lipophilicity, the dissociation of SAs may also influence the uptake and translocation process. Larger TF and positive correlation with log D ow indicate preferential translocation of pepper SAs. There was a significant ( p  < 0.05) dissipation gradient of SAs observed away from the vegetable roots. In addition, pepper could uptake more SAs under solo exposure, while rape accumulated more SAs under combined exposure. When SAs applied in mixture, competition between SAs might occur to influence the translocation and dissipation patterns of SAs.