Metal accumulation and rhizosphere microbial associations in Nymphaea lotus and Limnocharis flava from a natural wetland

Heavy metal distribution of natural and reclaimed tidal riparian wetlands in south estuary, China

Environmental degradation due to lead (Pb) and cadmium (Cd) pollution has been increasing. One of the alternative cost-effective green technologies to clean up heavy metal contamination is phytoremediation. This research aims to determine the potential of wild-found plants that could be used as Pb and Cd bioaccumulators. Plant species in this study were collected from heavy metal-contaminated soil in Bekasi and Karawang, West Java. Five species, namely Saccharum spontaneum, Acorus calamus, Ipomoea fistulosa, Ludwigia hyssopifolia, and Eichhornia crassipes, were studied for Pb accumulation capacity. Furthermore, five plant species, namely Limnocharis flava, Colocasia esculenta, Ipomoea fistulosa, Commelina benghalensis, and Eichhornia crassipes, were studied for their Cd accumulation capacity. The experiment was done in a greenhouse for eight weeks. Pb and Cd concentration were analyzed using atomic absorption spectrometry (AAS) to determine the uptake and translocation of Pb or Cd. I. fistulosa accumulated the highest amount of Pb, with a growth rate of up to 27.07 g week−1, a bioconcentration factor (BCF) of 1.46, and a translocation factor (TF) of 0.87 upon 300 mg kg−1 Pb treatment. C. esculenta showed considerable Cd bioaccumulation, as indicated by a BCF of 0.95 and a TF of 0.65, accompanied by sustained relative biomass increase (124.9%) and the highest growth rate (36.96 g week−1) among tested plant species upon 75 mg kg−1 Cd treatment. With their capacities for bioaccumulating Pb and Cd, respectively, I. fistulosa and C. esculenta were identified as potential accumulator species for phytoremediation in heavy metal-contaminated sites such as former mining lands, landfills, and highly polluted agricultural lands.

Rhizospheric Lactobacillus spp. contribute to the high Cd-accumulating characteristics of Phytolacca spp. in acidic Cd-contaminated soil

Phytofiltration of cadmium from water by Limnocharis flava (L.) Buchenau grown in free-floating culture system

Textile wastewater contaminated by heavy metal has been polluted to the agricultural land in Rancaekek, Bandung. To overcome the heavy metal contamination, phytoremediation technology has been proposed. Jatropha curcas plant with soil amendments (compost and EDTA) was utilized to investigate the heavy metal remediation in the contaminated soil. Five experimental treatments viz. S0 S1 S2 S3 and SE were set up for ninety days. The plant growth behaviour, heavy metal accumulation, and translocation (TF) and bioaccumulation (BAF) factors were determined. The untreated soil was indicated as silty loam containing Cd, Cr and Pb concentrations approximately 0.79, 100.15, and 8.43 mg/kg, respectively. The heavy metals were highly accumulated in the plant for treatments S3 and SE compared to control So. The accumulation of Cd, Cr and Pb in different J. curcas tissues can be classified as follow: root > shoot > leaves. Bioaccumulation and translocation factor of Cd were greater than one (BAF, TF > 1) while Cr and Pb were less than one (BAF, TF < 1). The highly removal of heavy metal was found that Cd = 81.73 % and Cr = 41.15% in S3 while Pb = 65.20 % in SE. To sum up, J. curcas species represented high TF and BAF in Cd removal, and low in Cr and Pb removal. It revealed that Jatropha curcas plant was suitable for phytoremediation of heavy metal contaminated soil, especially, combination with both compost and EDTA. Moreover, Jatropha curcas could be an emerging technology plant to alleviate the contaminated soil with multi-metal for sustainability of land resources.

Because of the inbuilt bio-accumulation mechanism several plants have shown a remarkable capability of accumulation of metals from contaminated soil into roots, tubers and upper parts of the plants. This study was undertaken to evaluate the bio-accumulation potential of a wild grass, Parthenium hysterophorus L., Asteraceae grown on the barren land along with the National highways for Cd, Cr, Cu, Ni and Pb by determining the bio-accumulated levels of these metals in the samples of soil, roots and shoot of the plant. The various bio-concentration factors (BCFs), translocation factors (TFs) and Biological accumulation coefficients (BACs) for studied metals were evaluated, to find out the suitability of Parthenium plant for phyto-extration of the studied metals. The order of observed levels of heavy metals in the samples of soil, root and shoots were: Pb (8.12±0.48) &gt; Cr (7.18± 0.39) &gt; Cu (5.64± 0.26) &gt; Ni (3.91± 0.21) &gt; Cd (1.31± 0.08) and Pb (6.67± 0.34) &gt; Cu (6.11 ±0.27) &gt;Cr (6.05± 0.23) &gt;Ni (4.14± 0.18) &gt; Cd (1.42± 0.11) and Pb (7.22±0.29) &gt; Cr (5.97±0.23)&gt;Cu (5.96 ±0.25)&gt;Ni (5.13±0.21) &gt; Cd (1.70±0.14 mg/Kg, dw), respectively. The soil to roots bio-concentration factors, BCFRoot for studied metals were: Cd (1.08) &gt; Cu (1.08) &gt;Ni (1.06) &gt; Cr (0.84)&gt;Pb (0.82). The order of root to shoot translocation factors, TFShoot for these metals in Parthenium hysterophorus L., was: Ni (1.24) &gt; Cd (1.20) &gt; Pb (1.08) &gt; Cr (0.99~1.00)&gt; Cu (0.98~1.00). The various soil to shoot biological accumulation coefficients, BACShoot for studied metals in Parthenium plant were, Ni (1.31) &gt; Cd (1.30)&gt; Cu (1.06) &gt; Pb (0.89) &gt;Cr (0.83), respectively. Comparatively higher BCF &gt;1, TF &gt;1 and higher BAC values for metals under study suggested that the plant Parthenium hysterophorus L has potential to translocate these metals to the above ground parts of the plants and thereby their phyto-extraction from contaminated soil.

Background.This study examines an intervention strategy to reduce the risk of chromium (Cr) exposure. It follows a previous Cr exposure investigation, which revealed that large volumes of Cr-contaminated waste were burnt on site. The study site had a long history of land-based waste disposal since 1994.Objective.The potential for phytoremediation using bamboo species to restore Cr-contaminated soil was evaluated.Methods.Chromium levels and physico-chemical properties of the tannery and control soils were analyzed before transplanting six different bamboo species. Translocation, bio-concentration and bioaccumulation factors of the species were assessed for phytoremediation capabilities.Results.Chromium levels in the tannery soils ranged from 1337.0 to 3398.0 mg/kg dw. The chromium levels were significantly higher (P < 0.05) than those of the control soils (0.20 to 2.34 mg/kg dw) and markedly exceeded the recommended limit of 100 mg/kg dw. The physicochemical properties of the tannery soils were also significantly varied (P < 0.05) compared to the control soils. In all cases, the species grown in the tannery soils were tolerant to a wide range of prevailing conditions. All of the bamboo species in the present study had a 100% survival rate in the tannery soils, except for D. birmanicus, which had a survival rate of 83.3%. Moreover, growth performance of the species in the tannery and control soils as evaluated by height and clump diameters did not vary significantly (P > 0.05). However, Cr levels in the tannery differed significantly (P < 0.05) among the species and rhizosphere soils. D. asper, B. vulgaris, D. membranaceus and B. blumeana had a bio-concentration factor (BCF) > 1 and translocation factor (TF) < 1, indicating that they are suitable for phytostablization. On the contrary, B. bambos had a bioaccumulation factor (BAF) < 1 and TF > 1, indicating potential for phytoextraction, while D. birmanicus showed no potential for phytoextraction or phytostabilization.Conclusions.The present study identified D. asper, B. vulgaris, D. membranaceus and B. blumeana as suitable for restoration of Cr-contaminated tannery sites. Close monitoring of toxic metals is necessary during application of these species. Further studies are also recommended using a wide variety of bamboo species to optimize their application in phytoremediation.

This study investigated the effects of alkaline silicon-based amendment (A) and incorporated with biochar (B) on the growth, heavy metal translocation, and accumulation of vetiver grass (Vetiveria zizanioides) grown in multi-metal-contaminated soils. Soil incubation for 6 months and pot experiments for 6 months were performed to investigate the growth and the translocation factor (TF) and bioaccumulation factor (BCF) values of heavy metals in vetiver grown in As-, Cd-, Cr-, and Pb-contaminated soils amended with A (0.5%) and AB (0.5% A; 1.5% B). The vetiver could grow in multi-metal-contaminated soils due to the restriction of metals translocation in vetiver. Vetiver could be the plant for phytostabilization of As, Cr, Cd, and Pb because As, Cr, Cd, and Pb accumulated by the vetiver were largely retained in the roots, as the TF values for As, Cr, Cd, and Pb were < 1; the BCF values for As, Cr, Cd, and Pb were obviously greater in roots than shoots. Application of A and AB markedly improved vetiver growth due to A- and AB-induced accumulation of Cd, Pb, and Cr in the roots, and then enhanced phytostabilization of Cd, Pb, and Cr in roots based on the BCF values, and the immobilization of Cd and Pb in soils based on increase of soil pH and Si-induced accumulation of Cd, Pb, and Cr in the roots. Vetiver represents a candidate for revegetation of multi-metal-contaminated soils amended by A or AB. Further investigations are required to determine the feasibility of revegetation in multi-metal-contaminated soils at the field scale.

In the present study, seven heavy metals, i.e., Cr, Cd, Fe, Mn, Cu, Pb and Mg were used for estimation of heavy metal pollution and the bioconcentration and translocation factors corresponding to the plant Eichhornia crassipes in Deepor Beel, Assam, India. Sediment and water hyacinth (Eichhornia crassipes) samples were collected from three different zones of the wetland; zone I is proximate to the Boragaon landfill region, zone II is the central portion of the wetland and zone III constitutes the site in the industrial zone. It was observed that the heavy metal concentrations in the sediment column of the wetland are significantly higher compared to the water hyacinths. Furthermore, in the water hyacinth samples collected from the three zones, it was observed that the heavy metal concentrations were significantly higher in the roots as compared to the shoots. This indicated an insignificant translocation of heavy metals from the roots to the shoots, as a result of which, all the heavy metals are concentrated in the roots. This was verified by the translocation factor, whose values were found to be minimal and inconsequential. Also, the bioconcentration factor of the water hyacinth samples was estimated and found to be higher in the central and industrial region, which suggests that the metal availability was very low in the landfill region, despite having considerably higher concentrations of heavy metals in the sediments. The findings of the study would prove to be consequential in determining the adverse effects of eutrophication and heavy metal contamination in the wetland, which would thereby aid in undertaking necessary steps in curbing the pollution levels.KeywordsHeavy metal pollutionSediment contaminationBioconcentration factorTranslocation factor Eichhornia crassipes

Heavy metal contamination in farmland soils threatens food security and human health. Phytoremediation provides a sustainable strategy, with Pueraria thomsonii emerging as a promising candidate due to its high-biomass production. However, its metal accumulation dynamics remain uncharacterized. Therefore, a 3-year field experiment was conducted to investigate biomass production, the accumulation of heavy metals (Cd, Cr, As, and Pb) across growth stages, and the bioconcentration factor (BCF), translocation factor (TF), and removal rate in P. thomsonii. Results showed that P. thomsonii produced a total biomass of 10.81–21.22 t ha−1, accumulating 76.95–170.61 (Cd), 30.80–43.28 (Cr), 7.12–9.09 (As), and 18.16–39.30 (Pb) g ha−1 during 2020–2022. Stem Cd accumulation exceeded root tubers and leaves by 45%–205% at maturity, while leaf Cr, As, and Pb accumulation was higher than root tubers and stems by 149%–868%. Cd-BCF values >1 in stems and leaves indicated efficient bioaccumulation, contrasting with Cr-, As-, and Pb-BCF <1. Stem and leaf TF values of Cd, Cr, As, and Pb consistently exceeded >1 except for stem Cr TF in 2022. On average, in the 3-year experimental period, the removal rate of Cd surpassed Cr, As, and Pb by 94%–95%. Soil properties (organic matter, available N) significantly influenced BCF, while available N modulated TF. These findings suggest that the combination of high-biomass production and elevated Cd accumulation in stems positions P. thomsonii as a promising candidate for high-biomass phytoremediation of Cd-contaminated farmland soils.

BackgroundContinuous cropping of the same crop leads to land degradation. This is also called the continuous-cropping obstacle. Currently, intercropping tobacco with other crops can serve as an effective strategy to alleviate continuous cropping obstacles.ResultsIn this study, tobacco K326 and insectary floral plants were used as materials, and seven treatments of tobacco monoculture (CK), tobacco intercropped with Tagetes erecta, Vicia villosa, Fagopyrum esculentum, Lobularia maritima, Trifolium repens, and Argyranthemum frutescens respectively, were set up to study their effects on rhizosphere soil chemical properties and composition and structure of rhizosphere soil microbial community of tobacco. The 16 S rRNA gene and ITS amplicons were sequenced using Illumina high-throughput sequencing. tobacco/insectary floral plants intercropping can influence rhizosphere soil chemical properties, which also change rhizosphere microbial communities. The CK and treatment groups tobacco rhizosphere soil microorganisms had significantly different genera, such as tobacco intercropping with T. repens and A. frutescens significantly increased the number of Fusarium and intercropping T. erecta, V. villosa, L. maritima, T. repens, and A. frutescens significantly increased the number of Sphingomonas and unknown Gemmatimonadaceae. Additionally, intercropping T. erecta, V. villosa and L. maritima changed the rhizosphere fungal and bacteria community and composition of tobacco and the positive correlation between tobacco rhizosphere the genera of fungi and bacterial were greater than CK. The pathway of the carbohydrate metabolism, amino acid metabolism, and energy metabolism in rhizosphere bacteria were significantly decreased after continuous cropping. Fungal symbiotic trophic and saprophytic trophic were significantly increased after intercropping V. villosa, L. maritima and plant pathogen and animal pathogen were increased after intercropping T. repens and A. frutescens. Additionally, bacterial and fungal communities significantly correlated with soil chemical properties, respectively.ConclusionThis study reveals that intercropping tobacco with insectary floral plants, particularly T. erecta, V. villosa, L. maritima and A. frutescens significantly affects soil chemical properties and alters rhizosphere microbial communities, increasing the abundance of certain microbial genera. Additionally, intercropping enhances pathways related to carbohydrate, amino acid, and energy metabolism in rhizosphere bacteria. These findings suggest that intercropping could provide a promising strategy to overcome challenges associated with continuous tobacco cropping by regulating the rhizosphere environment.

Toxicity of heavy metals above the normal threshold constituted a threat to humanity and biodiversity. Phytoremediation has become a novel and emerging technology of cleaning polluted sites through the use of plants. A study was carried out at the screen house located besides the academic building of the Federal University of Technology, Akure, Nigeria, to evaluate the phytoremediation potential of Amaranthus hybridus L. (Caryophyllales: Amaranthaceae) on a brewery effluent. The parameters investigated include chlorophyll content, the concentration of the metals in the plants, Bioconcentration Factor (BCF) and Translocation Factor (TF) was studied. Three different concentrations of brewery effluent were used at 50, 100 and 150 mL/5 kg of soil, respectively. The results of this study under controlled conditions indicate that effluent application increased chlorophyll content, reduced plant height and stem girth. Three heavy metals (iron, cadmium, and chromium) were detected in the shoots and leave of both plants after the experimental period. The translocation factor (less than 1) and bioaccumulation factors (greater than 1) were below the permissible limits hence indicating a possible bio-accumulator for the heavy metals investigated. Brewery effluent reduce the plant height but increase the leaf area of A. hybridus under high concentrations which possibly suggest an adaptive mechanism developed by the plant under stress.

Combined application of silicon and nitric oxide jointly alleviated cadmium accumulation and toxicity in maize

Rapid industrialization in China has led to widespread soil contamination, particularly with heavy metals like cadmium (Cd). This study investigates Cd accumulation and translocation in 12 commercial maize cultivars grown on contaminated soils. Initial soil Cd concentrations averaged 0.68 mg kg−1, exceeding safe limits for agricultural soils. Post-harvest results indicated that the soil Cd concentration decreased under all cultivars, with values ranging from 0.25 to 0.55 mg kg−1, indicating effective Cd uptake by maize. The bio-concentration factor (BCF) values indicated Cd accumulation, varying between 0.016 and 0.051, while translocation factor (TF) values ranged from 0.04 to 0.12. Cultivar C868 (pollution index (Pi) = 0.048, BCF = 0.016 and TF = 0.05) and C380 (Pi = 0.071, BCF = 0.023 and TF = 0.09) were the best cultivars on contaminated soils, which demonstrated reduced Cd uptake and limited translocation to grains. In addition, a strong positive correlation (r = 0.72, p < 0.05) was observed between soil Cd, Pi, BCF and TF, indicating that cultivars grown on high Pi soils, with higher Cd uptake and translocation result in higher accumulation of Cd in grains. The combined VNIR-PLSR model showed strong predictive performance for the prediction of Cd (R2 = 0.67 and RPD = 2.4). Spectral analysis revealed significant increases of reflectance at 450–500 and 600–700 nm associated with Cd absorption. Our findings indicated the capability of VNIR spectroscopy coupled with PLSR method as a reliable and efficient method for soil Cd assessment.

Cadmium Uptake From Soil by Ornamental Metallophytes: A Meta-analytical Approach.