Phytoremediation Potential Of Plants Research Articles

Assessment of phytodiversity and phytoremediation potential of plants in the vicinity of a thermal power plant

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 PM2.5 and PM10 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.

Synergistic effect of biochar and plant growth promoting bacteria improve the growth and phytostabilization potential of Sorghum bicolor in Cd and Zn contaminated soils

The synergetic effect of biochar (BC) and plant growth promoting bacteria (PGPB) on phytoremediation potential of plants in heavy metal (HM) contaminated soils was not well understood. A pot experiment was carried out to evaluate the effects of banana pith derived BC (0, 2.5 and 5%, w/w) as soil amendment together with inoculation of PGPB Bacillus thuringiensis SE1C2 on the growth, physiological response and phytoremediation potential of Sorghum bicolor (L.) Moench in Cd and Zn contaminated soils. Combined treatment of BC 5% and SE1C2 increased plant shoot length, root length, fresh weight and dry weight but decreased Cd and Zn accumulation as compared to other treatments. The BC 5% treatment also increased SE1C2 colonization in rhizosphere soils and tissue interior of S. bicolor even under HM stress. In addition, the plants treated with BC 5% and SE1C2 also had increased chlorophyll, carotenoid and antioxidant enzymes while lower leaf malondialdehyde and proline contents which suggest their potential in improving HM stress tolerance in plants. Similarly, the combined BC 5% and SE1C2 treatment considerably improved enzymatic activities (acid phosphatases, alkaline phosphatases, β-glucosidase and urease) in HM contaminated soils. Thus, this study concludes that the combined treatment of Bacillus thuringiensis SE1C2 and banana pith BC could be exploited as an effective strategy for improving the plant growth and phytostabilization potential in HM contaminated soils.

Bioaccumulation of Heavy Metals in a Soil–Plant System from an Open Dumpsite and the Associated Health Risks through Multiple Routes

Screening various plant species to act as hyperaccumulators and associated health risks could serve as a sustainable solution for the bioremediation heavy metals (HMs). For the first time, the present study explored the phytoremediation potential of native plants, soil enrichment, and human health risks associated with the contamination of HMs in soil and plant samples collected from a municipal solid-waste open dump site. Soil and plant samples (n = 18 + 18) from the dumpsite and (n = 18) from the control site were analyzed for selected HMs, i.e., Chromium (Cr), Lead (Pb), Nickel (Ni), Iron (Fe), and Zinc (Zn). The phytoremediation potential of plants was assessed using the bioaccumulation factor (BAF), bioaccumulation coefficient (BAC), and translocation factor (TF), while soil pollution levels were evaluated using the contamination factor (CF), geoaccumulation index (Igeo), enrichment factor (EF), potential ecological risk index (PERI), and human health risk indices. The results revealed that based on TF and BAC values, Alhagi maurorum Medic., Astragalus creticus Lam., Cichorium intybus L., Berberis lycium Royle, and Datura stramonium L. were hyperaccumulators for Cr while Parthenium hysterophorus L. was a promising species for both Ni and Cr. Similarly, CF values for Fe, Ni, Pb, and Cr were >6, thereby showing very high contamination, while Igeo values for Fe, Ni, Pb, and Cr were (class 6, >5), showing that the soil was extremely polluted. Furthermore, EF values for Fe, Ni, Pb, Cr, and Zn were 2 < EF ≤ 5, depicting moderate enrichment, while PERI values were in the range of 91.31–195.84, employing moderate ecological risks (95 < PERI < 190) from the dumpsite’s soil. Moreover, for non-carcinogenic exposure, none of the analyzed metals exceeded the threshold limit HRI values > 1 in both adults and children. Likewise, in the case of carcinogenic effects, the CRI values were lower than the tolerable limits (1 × 10−6–1 × 10−4) in both adults and children. Moreover, almost all studied plants could be utilized for the phytoextraction of mentioned HMs. In future, the present study can help in the implementation of public policies to ensure sustainability and developmental activities in contaminated sites. Based on these results, it is concluded that there is a dire need of monitoring solid waste dumpsites due to various types of potential risks associated with the contamination of HMs. Moreover, to minimize the potential health problems arising from the dumpsite, it is substantive that special attention should be paid to work on sustainable and eco-friendly remedial measures.

Transfer of Potentially Toxic Elements in the Soil-Plant System in Magnesite Mining and Processing Areas

Mining activities, ore concentrations, and transport processes generate large amounts of pollutants, including hazardous elements, which are released into the environment. This work presents the results of experimental research aimed at evaluating the environmental risks of soil and plant contamination in two magnesite mining and processing areas in the Slovak Republic, and assesses the phytoremediation potential of dominant plant species. Eleven potentially toxic elements in the soil were investigated using X-ray fluorescence spectrometry (Cd, Pb, Cr, Zn, Cu, As, Ni, Mn, Mg, Fe) and atomic absorption spectrometry (Hg). In plants, potentially toxic elements were investigated using inductively coupled plasma mass spectrometry (Cu, As, Cd, Pb) and inductively coupled plasma atomic emission spectrometry (Cr, Zn, Mn, Mg). Selected soil parameters (pH, redox potential, and soil organic matter) were also investigated. Soil contamination was evaluated using environmental indices (geoaccumulation index—Igeo, enrichment factor—EF, contamination factor—Cf, degree of contamination—Cd). The phytoremediation potential of plants was evaluated using the bioconcentration factor (BCF) and the translocation factor (TF). The soil reaction in the studied areas indicated a strong alkalization of the soil. The soils in Jelšava-Lubeník were significantly contaminated with Cr, As, Mn, and Mg. The most significant enrichment based on the average values of EF was found to be in the order of Cd > Mg > Zn > Cu > As > Cr > Ni > Pb > Fe > Hg > Mn. The observed values of Cf and Cd indicated a high degree of soil contamination. In Košice, the soils were found to be significantly contaminated with Cr, Mn, Mg, and Ni. The most significant enrichment was found in the order of Cd > Mn > Ni > Pb > Zn > Mg > Cu > As > Fe > Cr > Hg. Very high Cf was found for Pb and Cr. The results of correlation and hierarchical cluster analyses suggest a similar origin of pollutants caused by significant anthropogenic interventions due to magnesite mining and processing. The investigated dominant plant species, Phragmites australis, Agrostis stolonifera, Elytrigia repens, and Taraxacum officinale are able to accumulate high concentrations of the monitored potentially toxic elements without more serious load or damage. The results of BCF and TF confirmed that P. australis and T. officinale appeared to be suitable accumulators in the phytoextraction process. In the case of E. repens and A. stolonifera it was confirmed that they accumulate and immobilize high concentrations of potentially toxic elements, especially in the roots, establishing the suitability of their use in phytostabilization processes.

EVALUATION OF LEAD TOLERANT PLANT GROWTH PROMOTING RHIZOBACTERIA FOR PLANT GROWTH AND PHYTOREMEDIATION IN LEAD CONTAMINATION

The present study was conducted to evaluate five pre-characterized lead tolerant plant growth promoting rhizobacteria: Pseudomonas gessardii strain BLP141 (S2), Pseudomonas fluorescens A50 (S5), Pseudomonas syringae pv. syringae B728a (S6), Pseudomonas stutzeri strain 28a24 (S8) and Pseudomonas fluorescens strain LMG 2189 (S10), for their plant growth promotion, phytoremediation potential and physiological response on Helianthus annuus L. as test crop, exposed to different lead concentrations (300, 600 and 900 mg/kg). Crop was harvested after 30 days of sowing and data regarding growth parameters (root shoot length, root shoot fresh and dry weights), physiological attributes (photosynthetic rate, transpiration rate and substomatal CO 2 ), and lead content in root and shoot of sunflower, were recorded. Results revealed that lead contamination decreased the growth and physiological attributes of plants at all levels of lead stress; however inoculation with lead tolerant rhizobacteria reversed the toxic effect of lead on the plants and improved the growth and physiological attributes of sunflower in lead contamination, as compared to plants grown in the un-inoculated lead contaminated treatments. Among the five isolates, S2, S5 and S10 promoted more growth, improving the physiological attributes and phytoremediation potential of plants at all levels of contamination as compared to plants grown in lead stress without inoculation.

Phytoremediation potential of Phalaris arundinacea, Salix viminalis and Zea mays for nickel-contaminated soils

The aim of this study was to evaluate the usefulness of Phalaris arundinacea, Salix viminalis and Zea mays to the phytoremediation of the soil contaminated with nickel. A 2-year microplot experiment was carried out with plants growing on Ni-contaminated soil. Microplots (1 m2 × 1 m deep) were filled with Haplic Luvisols soil. Simulated soil contamination with Ni was introduced in the following doses: 0—no metals, Ni1—60, Ni2—100 and Ni3—240 mg kg−1. The phytoremediation potential of plants was evaluated using a tolerance index, bioaccumulation factor, and translocation factor. None of the tested plants was a species with high Ni phytoremediation potential. All of them demonstrated a total lack of usefulness for phytoextraction; however, they can be in some way useful for phytostabilization. Z. mays accumulated large amounts of Ni in the roots, which made it useful for phytostabilization, but, at the same time, showed little tolerance to this metal. For this reason, it can be successfully used only on soils medium-contaminated with Ni, where a large yield decrease did not occur. Its biomass may be safely used as cattle feed, as the Ni transfer from roots to shoots was strongly restricted. P. arundinacea and S. viminalis accumulated too little Ni in the roots to be considered as typical phytostabilization plants. However, they may be helpful for phytostabilization due to their high tolerance to Ni. These plants can grow in the soil contaminated with Ni, acting as a protection against soil erosion or the spread of contamination.

Recycling stabilised/solidified drill cuttings for forage production in acidic soils

Stabilisation/solidification (S/S), which involves fixation and immobilisation of contaminants using cementitious materials, is one method of treating drill cuttings before final fate. This work considers reuse of stabilised/solidified drill cuttings for forage production in acidic soils. It sought to improve the sustainability of S/S technique through supplementation with the phytoremediation potential of plants, eliminate the need for landfill disposal and reduce soil acidity for better plant growth. Drill cuttings with an initial total petroleum hydrocarbon (TPH) concentration of 17,125 mg kg−1 and low concentrations of metals were treated with 5%, 10%, and 20% cement dosages. The treated drill cuttings were reused in granular form for growing a forage, elephant grass (Pennisetum purpureum), after mixing with uncontaminated soil. The grasses were also grown in uncontaminated soil. The phytoremediation and growth potential of the plants was assessed over a 12-week period. A mix ratio of one part drill cuttings to three parts uncontaminated soil was required for active plant growth. The phytoremediation ability of elephant grass (alongside abiotic losses) reduced the TPH level (up to 8795 mg kg−1) in the soil-treated-drill cuttings mixtures below regulatory (1000 mg kg−1) levels. There were also decreased concentrations of metals. The grass showed better heights and leaf lengths in soil containing drill cuttings treated with 5% cement dosage than in uncontaminated soil. The results suggest that recycling S/S treated drill cuttings for forage production may be a potential end use of the treated waste.

Phytoremediation Potential of Plants Growing on the Pb-Contaminated Soil at the Song Tho Pb Mine, Thailand

ABSTRACTThe contamination of lead (Pb) is one of the main environmental problems on a global scale. This study assessed the potential of native metallophytes growing on the Song Tho Pb mine in Kanchanaburi province, Thailand, by a field survey. Plants and the associated soil samples were collected. Total Pb concentrations were analyzed by a flame atomic absorption spectrophotometer after a microwave-assisted acid digestion. While total Pb concentrations of top soils varied from 4881 to 16,720 mg/kg, those in soil around the roots ranged from 421 to 48,883 mg/kg. A total of 12 species belonging to eight families accumulated Pb concentrations in roots (47–32,633 mg/kg) which were higher than those in shoots (non-detected values – 1489 mg/kg). Bidens pilosa, with Pb accumulation in shoots > 1000 mg/kg and translocation factor (TF) > 1, could be useful in phytoextraction as a hyperaccumulator. Thysanolaena latifolia and Mimosa pudica with bioconcentration factor > 1 and TF < 1 could be useful in phytostabilization as excluders. So far, not many Pb hyperaccumulators are reported. The results from this study proposed a new candidate, B. pilosa, for Pb extraction. The potential use of these three phytoremediators should be further investigated using hydroponic and pot experiments.

Bioaccumulation of nickel by E. sativa and role of plant growth promoting rhizobacteria (PGPRs) under nickel stress

Phytoremediation potential of plants can be enhanced in association with microbes. Further, many plant growth-promoting rhizobacteria can improve growth under stress. The present study was conducted to investigate the effect of Pseudomonas putida (P. putida) on nickel (Ni) uptake and on growth of Eruca sativa (E. sativa). Three different levels of Ni (low; 150ug/g, medium; 250ug/g and high; 500ug/g) were applied to the soil containing E. sativa seedlings, with or without P. putida. Ni-toxicity was measured by metamorphic parameters including shoot length, root length, biomass, chlorophyll and proline and Ni contents. Inoculation with P. putida increased 34% and 41% in root and shoot length and 38% and 24% in fresh, dry weight respectively, as compared to non-inoculated plants. Similarly, Ni uptake increased by up to 46% following P. putida inoculation as compared to non-inoculated plants. Indole acetic acid, siderophore and 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity in the growing media enhanced growth and Ni uptake in E. sativa. The present results offer insight on Plant Growth Promoting Rhizobacteria (PGPR), such as P. putida, for the potential to enhance the plant growth by inhibiting the adverse effects of Ni in E. sativa.

Gentle remediation at the former “Pertusola Sud” zinc smelter: Evaluation of native species for phytoremediation purposes

The master plan for a soil clean-up of the former zinc smelter “Pertusola Sud” (Crotone, Italy) considered gentle remediation options for a specific area where both by-products and industrial wastes had been disposed in the past. Although the soil is severely contaminated by metals (Cd, Cu, Ge, Hg, In, Pb, Tl and Zn) and metalloids (As and Sb), several plant species grow spontaneously in this area. Plants and soil samples were collected and analysed for trace element concentrations.In the shoots of Dittrichia viscosa the Cd concentration (112mgkg−1) exceeded the hyperaccumulation threshold. Phragmites australis and Silene bellidifolia concentrated about 30 and 40mgkg−1 of Tl in their shoots, respectively. Sb accumulation in leaves of Acacia saligna, Eucalyptus camaldulensis and P. australis was more than 20 times higher than herbs. The highest Zn concentration in shoots was recorded in D. viscosa (1172mgkg−1). The phytoremediation potential of plants was evaluated considering the concentration of metals and metalloids in the plant tissues and also the bioconcentration factor (BF) and translocation factor (TF). The plant requirements for Sb phytoextraction were verified for P. australis (1.66 BF, TF 9.02), and for E. camaldulensis (BF 1.11, TF 1.71) and Galactites elegans (BF 2.30, TF 1.37) for Tl. Scirpoides holoschoenus could be considered for phytostabilization and recommended to restore a green cover on bare soils at the Pertusola Sud site.

Exposure and bioavailability of arsenic in contaminated soils from the La Parrilla mine, Spain

Arsenic derived from mining activity may contaminate water, soil and plant ecosystems resulting in human health and ecotoxicological risks. In this study, exposure assessment of arsenic (As) in soil, spoil, pondwater and plants collected from the areas contaminated by mine tailings and spoils in and around the La Parrilla mine, Caceres province, Spain, was carried out using AAS method. Water solubility, bioavailability and soil–plant transfer coefficients of As and phytoremediation potential of plants were determined. Arsenic concentrations varied from 148 to 2,540 mg/kg in soils of site 1 and from 610 to 1,285 mg/kg in site 2 exceeding the guideline limit for agricultural soil (50 mg/kg). Arsenic concentrations in pond waters varied from 8.8 to 101.4 μg/l. High concentrations of water-soluble As in the soils that ranged from 0.10 to 4.71 mg/kg in site 1 and from 0.46 to 4.75 mg/kg in site 2 exceeded the maximum permitted level of water-soluble As (0.04 mg/kg) in agricultural soils. Arsenic concentrations varied from 0.8 to 149.5 mg/kg dry wt in the plants of site 1 and from 2.0 to 10.0 mg/kg in the plants of site 2. Arsenic concentrations in plants increased in the approximate order: Retama sphaerocarpa < Pteridium aquilinum < Erica australis < Juncus effusus < Phalaris caerulescens < Spergula arvensis in site 1. The soil–plant transfer coefficients for As ranged from 0.001 to 0.21 in site 1 and from 0.004 to 0.016 in site 2. The bioconcentration factor based on water-soluble As of soil varied from 3.2 to 593.9 in the plants of site 1 whereas it varied from 2.1 to 20.7 in the plants of site 2. To our knowledge, this is the first study in Europe to report that the fern species P. aquilinum accumulates extremely low contents of As in its fronds despite high As levels in the soils. Therefore, the S. arvensis, P. caerulescens and J. effusus plant species grown in this area might be used to partly remove the bioavailable toxic As for the purpose of minimization of mining impacts until hypothetical hyperaccumulating and/or transgenic plants could be transplanted for the phytoremediation of As contaminated soils.