Metal Translocation Factor Research Articles

Differential growth and metal uptake efficiency of castor bean genotypes on a lead contaminated soil

<p>Present study investigated the unknown responses of five castor bean genotypes to lead (Pb) contaminated soil, focusing on their growth and metal uptake efficiency. A unique aspect is the simultaneous assessment of multiple genotypes, offering a holistic view of their reactions to soil contamination. Five castor genotypes (NIAB Gold, NIAB Spineless, NIAB-2020, DS-30, and C-3) were grown in pots filled with soil spiked with varying concentrations of Pb (0, 100, 200, 400, and 800 mg kg-1). Results have shown that increasing Pb concentrations led to a general decrease in plant biomass and photosynthetic pigments in all castor genotypes, however NIAB-2020 and DS-30 showcased remarkable resilience. Interestingly, the activities of antioxidant enzymes revealed a contrasting pattern. While superoxide dismutase and peroxidase activity declined, catalase and ascorbate peroxidase activity increased with higher Pb levels. Notably, DS-30 and NIAB-2020 exhibited the maximum catalase and ascorbate peroxidase activity at highest Pb concentration. Furthermore, these genotypes displayed impressive Pb uptake, particularly in their roots, exceeding the other tested genotypes. With metal translocation factor less than 1, NIAB-2020 and DS-30 showed promising potential for phytostabilization through efficient Pb accumulation, coupled with strengthened antioxidant defense mechanisms and restricted translocation, making them compelling candidates for eco-friendly remediation strategies.</p>

Assessing the effect of heavy metals on maize (Zea maysL.) growth and soil characteristics: plants-implications for phytoremediation

BackgroundHeavy metal pollution has become a global environmental issue. Heavy metals are contaminating the agro-soils, growing crops, and vegetables through different agricultural practices. In this study, besides the phytoremediation potential of maize, the role of chromium (Cr) and lead (Pb) on crop and soil health has been investigated.MethodsTwo maize varieties, Pak-Afgoi and Neelem, were grown under varying concentrations of Cr (50–300 ppm) and Pb (30–300 ppm) and different growth parametersi.e., seed germination, leaf size/number, stem girth, plant height, biomass, chlorophyll content, relative growth rate (RGR), and net assimilation rate (NAR) were studied under Cr and Pb stress. Likewise, the effect of metals was also assessed on different soil characteristics including soil texture, pH, EC, soil organic matter, urease activity and nutrients.ResultsStudied plant attributes were adversely affected by heavy metals toxicity. Affected values of RGR and NAR showed a linear correlation with affected growth and dry matter yield of maize. Heavy metals impacted different soil parameters including soil microbial performance and revealed a declining trend as compared to control soil. Maize varieties showed a significant phytoremediation potentiali.e., uptake of Cr and Pb was 33% and 22% in Pak-Afgoi, while Neelem showed 38% and 24% at 300 ppm, respectively. Data regarding metal translocation factor (TF), bioaccumulation factor (ACF), and biomagnification ratio (BMR) significantly revealed the potential of maize varieties in the removal of Cr and Pb metals from affected soils. However, Cr-accumulation was higher in shoots, and Pb accumulated in plant roots showed a differential behavior of metal translocation and affinity with the varieties. These maize varieties may be recommended for general cultivation in the Cr and Pb-contaminated areas.

Impact assessment of heavy metals spiked waste water irrigation on metals accumulation and translocation in marigold (Tagetes patula L.)

A pot experiment was conducted to find out the impact assessment of heavy metals spiked wastewater irrigation on growth, keeping quality and productivity of marigold (Tagetes patula L., cv.Pusa Arpita) at Water Technology Centre of ICARIndian Agricultural Research Institute, New Delhi during Rabi season of 2020-21. Sevan treatments were takenas T-1: Sole Groundwater Irrigation without spiking of heavy metal, T-2: Sole Wastewater Irrigation without spiking of heavy metal, T-3: Wastewater Irrigation spiked with Cd (0.005ppm), Cr (0.05ppm), Ni (0.1ppm) and Pb (2.5ppm), T-4: Wastewater Irrigation spiked with Cd (0.01ppm), Cr (0.1ppm), Ni (0.2ppm) and Pb(5.0ppm), T-5: Wastewater Irrigation spiked with Cd (0.1ppm), Cr (0.1ppm), Ni (2ppm) and Pb (10ppm) , T-6: Wastewater Irrigation spiked with Cd (0.25ppm), Cr (2.5ppm),Ni (5ppm) and Pb (30ppm), T-7: Wastewater Irrigation spiked with Cd (0.5ppm), Cr (5.0ppm), Ni (10ppm) and Pb (50ppm). Results indicated that Ni, Cr, Cd and Pb concentrations in the root part ranged from 2.05 to 54.48, 13.67 to 86.35, 0.89 to 5.21 and 3.84 to 22 mg/kg, respectively and in shoot parts ranged from 9.3 to 63.05, 29.99 to 97.4,1.8 to 6.42 and 12.38 to 29.93mg/kg, respectively, in marigold under different treatments of heavy metals spiked wastewater irrigation. Heavy metal translocation factors (TF) ranged from 0.22 to 0.87, 0.47 to 0.88, 0.38 to 0.82 and 0.32 to 0.75 for Ni, Cr, Cd and Pb, respectively and bioaccumulation factors (BF) for heavy metals (Ni, Cr, Cd and Pb) were varied from 63.8 to 114.47, 39.76 to 72.18, 34.21 to 64.57 and 6.3 to 12.61, respectively, in marigold under different treatments of heavy metals spiked wastewater irrigation. However, long-term application of heavy metals rich wastewater in marigold needs to be monitored at different soil and climatic conditions.

Dodonaea viscosa (Sapindaceae) as a phytoremediator for soils contaminated by heavy metals in abandoned mines.

Dodonaea viscosa (L.) Jacq. is a plant with a wide distribution that expands throughout almost all Mexican territory and is used in traditional medicine to treat many ailments. This species has been found associated with polluted areas, including mine tailings. Huautla, Morelos, Mexico, was a metallurgic district where mining activities generated 780,000 tons of waste rich in metals, deposited at 500m from the town without any treatment; this situation has been related to different environmental threats and human health risks. The study was carried out for 18months on seedlings developed under greenhouse conditions in two treatments: control substrate and mine tailings substrate. The concentration of six metals (Cd, Cr, Cu, Fe, Pb, and Zn) was measured through atomic absorption spectrophotometry in plant tissues, roots, and leaves. Effects of metal exposure were analyzed by size, micro-morphological character changes, and genetic damage in foliar tissue using the comet assay. The results showed significantly higher metal concentrations in the roots and leaves of individuals growing on the mine tailing substrate in comparison to the same plants tissues growing on control substrate. Positive and significant relationships between exposure time and metal concentration in roots and leaves, and between metal bioaccumulation in leaves and genetic damage were registered. Four out of six micro-morphological and size characters evaluated decreased significantly in exposed plants, except for stomatic index and root biomass. The most important metals in terms of the number of significantly affected micro-morphological and size characters showed the next pattern: Fe > Cd = Cr = Pb > Cu > Zn. D. viscosa is an efficient accumulator of Cu, Cd, Fe, Pb, and Zn in its root and leaf tissues. Overall, metal translocation factors in exposed D. viscosa plants showed the following pattern: Zn > Cu > Cd. We conclude that D. viscosa has the potential to phytoextract (Zn, Cu, and Cd), and phytostabilize (Cu, Cd, Fe, Pb, and Zn) metals from polluted soils, and along with its abundance, natural establishment in mine tailings, high levels of metal translocation, and bioconcentration factors, without affecting plant development, it can be an ideal candidate for phytoremediation of metal polluted soils.

Fertilization assures mineral nutrition but does not overcome the effects of Fe accumulation in plants grown in iron ore tailings.

The rupture of Fundão dam was the biggest environmental disaster of the worlds' mining industry, dumping tons of iron ore tailings into the environment. Studies have shown that the Fundão dam's tailings are poor in nutrients and have high Fe and Mn concentration. In this context, our objective was to evaluate the growth performance of two native tree species (Bowdichia virgilioides and Dictyoloma vandellianum) in two treatments: fertilized soil and fertilized tailings. We hypothesize that the high concentrations of iron and manganese in the tailings can impair the growth performance of plants by interfering with the absorption of nutrients made available through fertilization. Soil and tailings samples were collected in the municipality of Barra Longa (MG, Brazil), and then fertilized with mixed mineral fertilizer ("Osmocote Plus 15-9-12" at 7.5g L-1). The experiment was conducted for 75days in a greenhouse using 180 cm3 tubes. We evaluate chlorophyll content, maximal PSII quantum yield, root length, shoot length, root:shoot ratio, leaf area, specific leaf area and leaf area ratio, dry mass, macro- and micronutrients concentration in the tissues, and metal translocation factor. Although assuring the adequate levels of the main nutrients to plant growth (N, P, K, Ca, and Mg), the fertilization did not reverse the negative effect of tailing on these species. The high concentration of Fe in the tissues associated with less biomass production, lower plant height, smaller leaf area, bigger specific leaf area, and reduced chlorophyll content indicates a probable phytotoxic effect of iron present in the tailings for D. vandellianum. Our results base further field evaluations and longer experiments, which will facilitate the understanding of the performance of tree species submitted to tailings with fertilization. So far, this study suggests that B. virgilioides are more tolerant to excess Fe from the tailings of Fundão dam than D. vandellianum.

Differential Growth and Metal Accumulation Response of Brachiaria Mutica and Leptochloa Fusca on Cadmium and Lead Contaminated Soil

ABSTRACT This work aims to assess growth, physiology, and metal uptake response of Brachiaria mutica and Leptochloa fusca under different contamination levels of Cd (10 and 50 mg kg−1) and Pb (50 and 250 mg kg−1) stress. Results of pot trial showed increasing metal concentration affected B. mutica more as compared to L. fusca. In B. mutica metal stress substantially reduced shoot dry biomass, root dry biomass, total chlorophylls, and carotenoids contents by 89%, 85%, 65%, and 61%, respectively, while enhanced the SOD activity up to 62 U min−1 g−1 FW. L. fusca showed better growth, chlorophylls and carotenoid contents, SOD activity (up to 79 U min−1 g−1 FW), shoot metal uptake potential (Cd 110 µg pot−1, Pb 91.57 µg pot−1), and root metal concentration (Cd 126 mg kg−1 dm, Pb 117 mg kg−1 dm) compared to B. mutica under Pb and Cd stress. While both grass species showed metal translocation factor less than unity under all levels of metal stress. Keeping in view the above results, it is concluded that L. fusca having better growth and physiology with TF < 1 could be used for phytostabilization of Pb and Cd to reclaim the soil having moderate to lower levels of contamination.

Metalliferous conditions induce regulation in antioxidant activities, polyphenolics and nutritional quality of Moringa oleifera L.

Moringa oleifera L. was grown under cadmium and lead stress conditions and the variations in its mineral content, polyphenolics, and antioxidant activities were studied and how these heavy metals affect plant growth and development. In this study, the metal translocation factor was found <1 which indicates more metal accumulation in moringa roots than stem. A significant increase in enzymatic and non-enzymatic antioxidant activities was observed in leaves, stem, and roots under metal stress which shows moringa can withstand under metalliferous conditions by regulating its antioxidant system. Various parts of moringa plants exhibited good nutritional quality; even significant variation was recorded in nutritional attributes. A significant variation was also noted in the expression of polyphenolics in moringa stem, roots, and leaves which are indicators of plant defense system under abiotic stress conditions. The results of the present study clearly manifest that the nutritional quality and concentration of polyphenolics in moringa plants are least affected by cadmium and lead uptake. These findings suggested the cultivation of moringa plants on cadmium and lead affected soils which cannot only remediate soil metalliferous conditions but can also provide nutritious fodder for livestock. For better understanding of the involved mechansisms, there is need to study the genes which are associated with moringa tolerance under metalliferous conditions.

PHYTOREMEDIATON OF HEAVY METALS FROM WASTEWATER BY CONSTRUCTED WETLAND MICROCOSM PLANTED WITH ALOCASIA PUBER

Water pollution by toxic heavy metals is a global environmental problem. It has led to the development of alternative technologies for heavy metals removal from contaminated sites. Constructed wetland microcosm by using Alocasia puber is a possible treatment method for wastewater containing heavy metals. Synthetic wastewater with heavy metals Cd, Cr, Cu, Ni, and Zn were used in this study. Several heavy metals concentrations (5 mg/L, 10 mg/L and 100 mg/L) were used in the systems. Six different hydraulic retention times (HRTs) (2, 4, 6, 8, 10 and 12 days) were tested in the present study. The results obtained showed removal efficiencies of heavy metals of &gt;99% after day 12. The removal of Ni from 10 mg/L solutions (initial concentrations) recorded the best removal efficiency. Heavy metal translocation factor (TF) was found to be less than 1 for all metals tested, which confirmed the significance of roots as heavy metals accumulator compared to stems or leaves of A, puber. Therefore, this study concluded that A, puber has a great potential as an important component in constructed wetlands for water contaminated with heavy metals.

Transfer and Accumulation of Some Heavy Metals in Native Vegetation Plants

Phytoremediation procedure can be defined as the use of selected plants in order to eliminate some heavy metals from the soil, or wastewater in a cost-effective method. This study aimed to investigate the concentrations of heavy metals such as Cd, Pb, Cu, Zn and Cr in soils and vegetation plants grown in Wadi Hanifa, Riyadh city, Kingdom of Saudi Arabia. Five sites have been chosen for collected plant samples (shoot and root) for one year, and five plant species have been chosen which distributed in the study area including Ziziphus spina-christi, Prosopis juliflora, Rhazya stricta, Ochradenus baccatus and Conocarpus erectus. Determination of Cd, Pb, Cu, Zn and Cr has been done with ICP. Accumulation coefficient (AC), and translocation factor (TF) have been calculated to evaluate the ability of selected plants to extract the heavy metals from soil. The results indicated that Ziziphus spina-christi and Conocarpus erectus showed the high ability to accumulate the Pb and Zn in its root and shoot compared with other plants. The trend of heavy metal translocation factors for different plants was in the order of Cd &gt; Cr &gt; Pb &gt; Cu &gt; Zn. The accumulation coefficient (AC) of the Cd, Pb, Zn, Cu and Cr in the roots/soil of Ziziphus spina-christi, Prosopis juliflora, Rhazya stricta, Ochradenus baccatus and Conocarpus erectus were varied from 0.80 to 3.60. The order of AC in the shoot as follows: Pb &gt; Cu &gt; Zn &gt; Cr &gt; Cd, while in roots of as follows: Cd &gt; Cr &gt; Pb &gt; Cr &gt; Zn.

Effect of pH on Cr(III) accumulation, biomass production, and phenolic profile in 2 Salvinia species.

We analyzed the effect of pH on Cr(III) accumulation, biomass production, and phenolic profile of Salvinia rotundifolia and Salvinia minima plants grown in the presence of increasing concentrations of CrCl3 . Biomass accumulation, metal tolerance index, and photosynthetic pigment contents indicate that Salvinia rotundifolia seems to be more tolerant of Cr(III) than S. minima at different pHs. Increased metal accumulation by Salvinia species under increasing pH could be explained by changes of the protonation status of cell wall functional groups because both the highest and the lowest pH values used in the present study were outside of the levels at which Cr(III) species start to precipitate. The metal translocation factor indicates that in buffered conditions S. rotundifolia tend to retain more Cr(III) in lacinias than S. minima, probably through the involvement of insoluble phenolics. The results of the present study could be useful to the management of solution pH to maximize the removal of Cr(III) by aquatic plants. Environ Toxicol Chem 2019;38:167-176. © 2018 SETAC.

Airborne foliar transfer of particular metals in Lactuca sativa L.: translocation, phytotoxicity, and bioaccessibility.

The uptake, translocation, and human bioaccessibility of metals originating from atmospheric fine particulate matters (PM) after foliar exposure is not well understood. Lettuce (Lactuca sativa L.) plants were exposed to micronic PbO, CuO, and CdO particulate matters (PMs) by the foliar pathway and mature plants (6weeks old) were analyzed in terms of: (1) metal accumulation and localization on plant leaf surface, and metal translocation factor (TF) and global enrichment factor (GEF) in the plants; (2) shoot growth, plant dry weight (DW), net photosynthesis (Pn), stomatal conductance (Gs), and fatty acid ratio; (3) metal bioaccessibility in the plants and soil; and (4) the hazard quotient (HQ) associated with consumption of contaminated plants. Substantial levels of metals were observed in the directly exposed edible leaves and newly formed leaves of lettuce, highlighting both the possible metal transfers throughout the plant and the potential for human exposure after plant ingestion. No significant changes were observed in plant biomass after exposure to PbO, CuO, and CdO-PMs. The Gs and fatty acid ratio were increased in leaves after metal exposure. A dilution effect after foliar uptake was suggested which could alleviate metal phytotoxicity to some degree. However, plant shoot growth and Pn were inhibited when the plants are exposed to PbO, and necrosis enriched with Cd was observed on the leaf surface. Gastric bioaccessibility of plant leaves is ranked: Cd > Cu > Pb. Our results highlight a serious health risk of PbO, CuO, and CdO-PMs associated with consumption of vegetables exposed to these metals, even in newly formed leaves in the case of PbO and CdO exposure. Finally, the study highlights the fate and toxicity of metal rich-PMs, especially in the highly populated urban areas which are increasingly cultivated to promote local food.

Influence of direct and alternating current electric fields on efficiency promotion and leaching risk alleviation of chelator assisted phytoremediation

Direct and alternating current electric fields with various voltages were used to improve the decontamination efficiency of chelator assisted phytoremediation for multi-metal polluted soil. The alleviation effect of electric field on leaching risk caused by chelator application during phytoremediation process was also evaluated. Biomass yield, pollutant uptake and metal leaching retardation under alternating current (AC) and direct current (DC) electric fields were compared. The biomass yield of Eucalyptus globulus under AC fields with various voltages (2, 4 and 10 V) were 3.91, 4.16 and 3.67kg, respectively, significantly higher than the chelator treatment without electric field (2.71kg). Besides growth stimulation, AC fields increased the metal concentrations of plant tissues especially in aerial parts manifested by the raised translocation factor of different metals. Direct current electric fields with low and moderate voltages increased the biomass production of the species to 3.45 and 3.12kg, respectively, while high voltage on the contrary suppressed the growth of the plants (2.66kg). Under DC fields, metal concentrations elevated obviously with increasing voltages and the metal translocation factors were similar under all voltages. Metal extraction per plant achieved the maximum value under moderate voltage due to the greatest biomass production. DC field with high voltage (10V) decreased the volume of leachate from the chelator treatment without electric field from 1224 to 56mL, while the leachate gathered from AC field treatments raised from 512 to 670mL. DC field can retard the downward movement of metals caused by chelator application more effectively relative to AC field due to the constant water flow and electroosmosis direction. Alternating current field had more promotive effect on chelator assisted phytoremediation efficiency than DC field illustrated by more metal accumulation in the species. However, with the consideration of leaching risk, DC field with moderate voltage was the optimal supplementary technique for phytoremediation.

Metal-resistant rhizobacteria isolates improve Mucuna deeringiana phytoextraction capacity in multi-metal contaminated soils from a gold mining area.

Phytoremediation consists of biological techniques for heavy metal remediation, which include exploring the genetic package of vegetable species to remove heavy metals from the environment. The goals of this study were to investigate heavy metal and bioaugmentation effects on growth and nutrient uptake by Mucuna deeringiana; to determine the metal translocation factor and bioconcentration factor and provide insight for using native bacteria to enhance heavy metal accumulation. The experiment was conducted under greenhouse conditions using a 2×4 factorial scheme with highly and slightly contaminated soil samples and inoculating M. deeringiana with three highly lead (Pb+2)-resistant bacteria Kluyvera intermedia (Ki), Klebsiella oxytoca (Ko), and Citrobacter murliniae (Cm) isolated from the rhizosphere of native plants identified as Senecio brasiliensis (Spreng.) Less., Senecio leptolobus DC., and Baccharis trimera (Less) DC., respectively. The increased heavy metal concentrations in soil samples do not decrease the root dry mass of M. deeringiana, concerning the number and dry weight of nodules. The shoot dry mass is reduced by the increasing concentration of heavy metals in soil associated with Kluyvera intermedia and Klebsiella oxytoca bacteria. The number of nodules is affected by heavy metals associated with Citrobacter murliniae bacteria. The bacteria K. intermedia, C. murliniae, and K. oxytoca increase the lead and cadmium available in the soil and enhanced metal uptake by Mucuna deeringiana. The M. deeringiana specie has characteristics that make it hyperaccumulate copper and zinc. The translocation and bioconcentration factors for M. deeringiana characterize it as a promising candidate to phytostabilize multi-metal contaminated soils.

Metal absorption properties of Mentha spicata grown under tannery sludge amended soil-its effect on antioxidant system and oil quality

Tannery sludge (TS) is hazardous to environment and its disposal in an ecofriendly manner is a major challenge. An experiment was conducted to investigate the metal absorption properties of Mentha spicata grown under different levels of TS amended soil (soil: sludge in 100:0, 75:25, 50:50, 25:75 and 0:100 ratio) and its effect on the antioxidant system and oil quality. At 75:25 ratio of sludge and soil, metal translocation factor was ≥0.5 for Cr, Cd, and Co and for Ni and for Pb ≥ 1. Carvone, limonene, dihydrocarvone and other oil constituents along with biomass were maximum in 75:25 ratio of sludge and soil. Superoxide dismutase (SOD), CAT (Catalases), POD (Peroxidases), MDA (Malondialdehyde) and proline play a major role in detoxification of reactive oxygen species generated due to TS (heavy metal stress). Antioxidant (SOD, CAT and POD), MDA and proline showed an increasing trend as the concentration of TS increased with the treatments. To test the relationship between 23 character principal component analysis (PCA) was performed. PC-I contributed 56% of total variance while PC-II contributed 37% of total variance. The results concluded that M. spicata performed well in terms of oil yield and multiple metal translocations in 75:25 sludge and soil ratio.

Editorial: Environmental phytoremediation: plants and microorganisms at work.

Editorial: Environmental phytoremediation: plants and microorganisms at work.

Evaluation of the Phytoextraction Potential at an Acid-Mine-Drainage-Impacted Site

Four plant species were found naturally growing at an acid mine drainage (AMD)-impacted site contaminated with 9430 mg kg−1Al, 76,000 Fe mg kg−1, ∼150 mg kg−1Mn, and 420 mg kg−1 Mg: soybeans (Glycine max), cattails (Typha latifolia), goldenrods (Solidago sp.), and reed grass (Phragmites australis). The metal uptake selectivity was Fe≫Mg∼Mn>Al for cattails, Mg>Mn>Fe>Al for goldenrods, and Fe≫Al>Mg>Mn for reeds. When metal translocation factors, shoot concentrations, and toxicity of the contaminants were correlated, cattails and reeds were more effective at the site than the soybeans or goldenrods. Cattails had a translocation factor of 3.71 for Al, 3.3 for Mg, 1.98 for Mn, and only 0.2 for Fe. The translocation factors for reeds were much higher for Fe (8.64) and Al (7.3). Cattails (1.11 mg Al g−1 shoot) and reeds (3.4 mg g−1 g shoot) were both able to hyperaccumulate Al. Additional research is warranted to ascertain if the uptake efficiencies can be enhanced by the use of chelators.

Interaction of Cd/Zn hyperaccumulating plant (Sedum alfredii) and rhizosphere bacteria on metal uptake and removal of phenanthrene

The effects of bacteria (Burkholderia cepacia) on plant growth, metal uptake, tolerance index and phenanthrene degradation by a hyperaccumulating plant (Sedum alfredii) were investigated. It was found that inoculation of bacteria did not enhance plant growth and metal uptake; while both metal translocation factor (up to 84% for Cd and 42% for Zn) and tolerance index (up to 23.2% for shoot and 72% for root) were significantly increased. In addition, inoculation of bacteria also alleviated the reductions of bioaccumulation factor and phytoextraction efficiency of As, Cu and Zn with the increasing proportions of polluted soil applied, while they were even increased for Cd and Pb (up to 31.2 and 124%, respectively). Up to 96.3% of phenanthrene was removed in the treatment with both plant and bacteria at the end of the experiment. A positive correlation between metal and P accumulation in plants was observed, it is suggested that high P uptake is directly involved in metal detoxification and leading to an increased P requirement. With the assistance of bacteria, S. alfredii could be able to withstand higher metal concentrations and it could also provide a practical tool for phytoremediation.

Heavy Metals in Water, Sediments, and Aquatic Macrophytes: River Hindon, India

AbstractConcentrations of heavy metals (Cd, Cu, Cr, Mn, Zn, Pb, and Ni) were investigated in water, sediments, and aquatic macrophytes (Eichhornia crassipes and Nelumbo nucifera) collected from the River Hindon, India. Quantitative analysis of data and evaluation of potential ecological risk index (RI) indicated that the river Hindon is suffering from serious metal contamination. Statistical analyses (cluster analysis and correlation analysis) suggested that heavy metal pollution in the river originates from anthropogenic sources, especially industrial and urban discharges. The study also revealed that the heavy metals were selectively accumulated in different parts of the aquatic macrophytes. Metal translocation factor (MTF) estimation of Eichhornia and Nelumbo sp. highlighted their phyto-remediation potential (Cd, Mn, Pb, and Ni), the latter being an unexplored plant species for such studies.

Heavy Metal Accumulation in Plant Species Indigenous to a Contaminated Portuguese Site: Prospects for Phytoremediation

Phytoremediation is a promising alternative to conventional soil clean-up methods; however, up to date, there is still not enough information on plant species suitable for application in this field of science. Therefore, plant screening on contaminated sites can lead to the identification of further species of interest. In the present study, pedological and botanical characteristics of an industrialised area known for its metal contamination, in special with Zn—Esteiro de Estarreja, in Portugal—were examined in a 1-year screening. Twenty-seven species were found, with a higher occurrence and variability in the summer/spring season. Zinc levels in the tissues of the collected plant samples ranged from 34 mg kg−1 in shoots to 2,440 mg kg−1 in roots of different species. Species as Verbascum virgatum, Hypochoeris radicata, Phalaris arundinacea, Conyza bilbaoana, Paspalum urvillei and Aster squamatus have shown high Zn shoot accumulation and bioconcentration factors (BCFshoots > 1) and high metal translocation factors (TF > 1). Others, namely Spergularia capillacea, excluded Zn from the shoot tissues and stored the metal at the root zone (BCFroots > 1), behaving as tolerant plants. Plants were also screened for arbuscular mycorrhizal fungi colonisation, and only few species showed mycorrhizal presence, namely C. bilbaoana, Hirschfeldia incana, Epilobium tetragonum, Conyza sumatrensis, Pteridium aquilinum, P. urvillei and A. squamatus. The present work showed important indigenous species that can cope with installed harsh conditions and with potential for utilisation in phytoremediation strategies, either through metal removal to aerial parts or through its immobilisation in the root zone.

Metal uptake and transport by Tyaha angustata L. grown on metal contaminated waste amended soil: An implication of phytoremediation

Typha angustata L. is a wetland plant commonly found in the marshy land or flood planes of the Ganges riverine system. A field study was taken on T. angustata L. to evaluate the uptake and transport of heavy metals (Mn, Cu, Zn, Cr, Ni and Pb) in different parts of plants grown on waste amended soils in water logged condition for 3 months. T. angustata L. accumulated Mn, Cu, Zn, Cr, Ni and Pb up to 119.21 ± 5.8 µg g − 1 , 4.18 ± 0.5 µg g − 1 , 5.72 ± 1.1 µg g − 1 , 15.4 ± 1.9 µg g − 1 , 5.3 ± 0.8 µg g − 1 and 7.21 ± 0.9 µg g − 1 in below ground organ (BL) respectively. Whereas, the maximum metal contents in above ground organ (AG) were 43.86 ± 3.2 µg g − 1 , 1.73 ± 0.04 µg g − 1 , 2.11 ± 0.07 µg g − 1 , 6.31 ± 0.3 µg g − 1 , 1.8 ± 0.04 µg g − 1 and 2.75 ± 0.03 µg g − 1 respectively. The plant also retained the tissue nitrogen up to 6.1 ± 0.38% in BL and 9.82 ± 0.54% in AG. It accumulated the maximum concentration of phosphorus 0.25 ± 0.02% in BL and 0.41 ± 0.02% in AG. Metals in both BL and AG were enriched with exposure, but the translocation factor was higher in BL in all amendments. Metal translocation factor was higher in BL/soil than AG/soil to a large extent. The translocation factor of metal from water to below ground organ was higher than water to above ground organ with a maximum value for Cr. There is a strong positive correlation of metal contents in plant tissue with soil organic matter (OM), and phosphorus contents in plant tissue. There is no significant correlation between metal uptake and nitrogen contents in plant tissue. This study reveals that T. angustata L. can be used for remediation of heavy metals containing waste when used in 25% waste amendment.