Special Issue "New Phytoremediation in Trace Elements Contaminated Soils"

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Soil and Plant Nutrition".

Deadline for manuscript submissions: closed (31 December 2021).

Special Issue Editors

Prof. Dr. Maria Pilar Bernal
E-Mail Website1 Website2
Guest Editor
Consejo Superior de Investigaciones Científicas, CEBAS-CSIC, E-30100 Murcia, Spain
Interests: soil contamination; phytoremediation; trace elements; organic wastes management; compost
Prof. Dr. Paula Alvarenga
E-Mail Website1 Website2
Guest Editor
Instituto Superior de Agronomia (ISA), University of Lisbon, 1649-004 Lisbon, Portugal
Interests: soil pollution; trace metals; soil quality assessment; organic wastes; soil amendments; phytoremediation
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Special Issue Information

Dear Colleagues,

Plant-based (“phyto”)-remediation comprises the so-called soft (or gentle) remediation practices, which take advantage of soil biological processes to promote natural soil remediation. These technologies are characterised by their low cost, low demand for infrastructure and low carbon footprint, so they are considered environmentally friendly. Phytoremediation consists of the use of the plants and their associated microorganisms, supported by soil amendments, to remove (phytoextraction), immobilise (phytostabilisation), volatilise (phytovolatilisation) or degrade the soil contaminants (phytodegradation).

The vast number of contaminated sites requires the continued development of new remediation strategies. The combination of different plant species, associated microorganisms and new materials as soil amendments seems to be the future trend for innovative decontamination solutions, which need to be tested under real conditions.

This Special Issue covers novel aspects of soil phytoremediation, including: new strategies for emerging inorganic pollutants and for mixed/combined contamination; criteria for remediated soils based on pollutant bioavailability, risk assessment, soil health and biodiversity; selection of plants tolerant of trace elements for specific soil and climatic conditions; new soil amendments to retain inorganic contaminants, thus reducing their bioavailability, toxicity and leaching risk. Both short-term experiments under controlled conditions and, especially, long-term validation experiments are welcome.

Prof. Dr. Maria Pilar Bernal
Prof. Dr. Paula Alvarenga
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Agronomy is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • phytoextraction
  • phytostabilisation
  • trace elements
  • soil amendments
  • bioavailability
  • risk assessment
  • remediation efficiency
  • soil health

Published Papers (5 papers)

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Research

Article
Testing Combined Effect of Amendments and Inoculation with Bacteria for Improving Phytostabilisation of Smelter Waste Extremely Contaminated with Trace Elements
Agronomy 2021, 11(10), 2064; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11102064 - 14 Oct 2021
Viewed by 333
Abstract
Smelter waste deposits pose environmental and health threats and require remediation actions. Phytostabilisation techniques, based on soil amendments, help to establish plant cover and limit the secondary emission of potentially toxic trace elements. However, methods to optimize their effectiveness are needed. The application [...] Read more.
Smelter waste deposits pose environmental and health threats and require remediation actions. Phytostabilisation techniques, based on soil amendments, help to establish plant cover and limit the secondary emission of potentially toxic trace elements. However, methods to optimize their effectiveness are needed. The application of bacterial inoculants in combination with soil amendments in the remediation of soils and wastes contaminated with metals still has not been extensively tested. Therefore, the aim of this study was to determine the effectiveness of indigenous (Streptomyces sp., Pseudomonas sp.) and foreign (Streptomyces costaricanus) strains of bacteria in supporting grass growth on extremely contaminated waste slag. They were applied alone and in combination with compost mixed with phosphate fertilizer or iron oxide. The tested strains improved plant growth and increased plant availability of phosphorus. The interaction of the soil amendments and some bacterial strains also stimulated a decrease in the extractability of metals, likely through the phosphate-induced precipitation of lead. Our data show that the effectiveness of soil amendments in the phytostabilisation of heavily polluted smelter deposits can be enhanced by plant growth-promoting bacteria (PGPB). Full article
(This article belongs to the Special Issue New Phytoremediation in Trace Elements Contaminated Soils)
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Article
Inoculated Seed Endophytes Modify the Poplar Responses to Trace Elements in Polluted Soil
Agronomy 2021, 11(10), 1987; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11101987 - 30 Sep 2021
Viewed by 492
Abstract
Seed endophyte inoculation can enhance the plant tolerance to pollutants, which allows plant cultivation on trace element (TE) polluted soils. Methylobacterium sp. CP3 and Kineococcus endophyticus CP19 were tested in vitro for their tolerance to Zn and Cd and their plant growth [...] Read more.
Seed endophyte inoculation can enhance the plant tolerance to pollutants, which allows plant cultivation on trace element (TE) polluted soils. Methylobacterium sp. CP3 and Kineococcus endophyticus CP19 were tested in vitro for their tolerance to Zn and Cd and their plant growth promotion traits. The in vivo effects of bioaugmentation with individual strains or both strains were tested using two poplar cultivars, Populus deltoides x (P. trichocarpa x P. maximowiczii) ‘Dender’ and ‘Marke’, grown in TE polluted soil for six weeks. Methylobacterium sp. was found to grow on media enriched with 0.4 and 0.8 mM Cd, and both endophytes tolerated 0.6 and 1 mM Zn, due to the presence of genes involved in Zn and Cd tolerance and transport. Methylobacterium sp. showed an extracellular ion sequestration mechanism. Production of indole-3-acetic acid by Methylobacterium sp. and K. endophyticus, as well as phosphorus solubilization by Methylobacterium sp. were observed. Bioaugmentation with both endophytes increased the shoot length of Populus ‘Marke’ and enhanced the Mg uptake in both cultivars. Inoculation with Methylobacterium sp. reduced the bioaccumulation of Zn in ‘Marke’, conferring it an excluder strategy. Methylobacterium sp. and K. endophyticus seemed to improve the plant nutritional status, which can alleviate abiotic stress. Full article
(This article belongs to the Special Issue New Phytoremediation in Trace Elements Contaminated Soils)
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Article
Biochar and Bacillus sp. MN54 Assisted Phytoremediation of Diesel and Plant Growth Promotion of Maize in Hydrocarbons Contaminated Soil
Agronomy 2021, 11(9), 1795; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091795 - 08 Sep 2021
Viewed by 732
Abstract
Contamination by petroleum hydrocarbons (PHs) is a great threat to environment due to the higher persistence and bio-toxicity of PHs. Therefore, removal of PHs from contaminated environment and strategies to reduce their toxic effects on living organisms are crucial for environmental safety and [...] Read more.
Contamination by petroleum hydrocarbons (PHs) is a great threat to environment due to the higher persistence and bio-toxicity of PHs. Therefore, removal of PHs from contaminated environment and strategies to reduce their toxic effects on living organisms are crucial for environmental safety and human health. The toxic effects of PHs from the polluted soil can be reduced by the addition of microbes and biochar. In this study, a pot trial was carried out to evaluate the effects of sugarcane bagasse (SB) biochar and Bacillus sp. MN54 addition on phytoremediation of PHs and growth of maize (Zea mays L.) in soil artificially contaminated with diesel. Maize seeds were sown in uncontaminated or contaminated (with PHs) soil, treated with biochar and Bacillus sp. MN54. The results revealed that PHs showed significant phytotoxicity to maize plants and the application of strain MN54 and biochar greatly reduced the toxic effects of PHs on plants growth and physiology by increasing the nutrients uptake in PHs contaminated soil. Interestingly, the phytotoxicity of PHs on maize plants was further reduced in the co-supplementation of strain MN54 and biochar. Plants physiological (25–48%) and agronomic (38–47%) attributes were significantly higher as compared to only PHs contaminated soil in the co-supplementation of strain MN54 and biochar. Similarly, nitrogen (41%), phosphorus (43%) and potassium (37%) concentrations were also increased in the co-supplementation of strain MN54 and biochar. Furthermore, maize plants successfully phytoremediate a considerable amount of PHs from soil particularly in the presence of strain MN54 and biochar, and this PHs removal was further enhanced in the co-supplementation of strain MN54 and biochar (i.e., 46% and 77% of initial PHs were removed in unplanted and planted treatments, respectively). The present results indicate that co-supplementation of biochar and Bacillus sp. MN54 could be effective in enhancing the degradation of PHs and improving plant growth in the hydrocarbons contaminated soil. Full article
(This article belongs to the Special Issue New Phytoremediation in Trace Elements Contaminated Soils)
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Article
Potential of the Biomass of Plants Grown in Trace Element-Contaminated Soils under Mediterranean Climatic Conditions for Bioenergy Production
Agronomy 2021, 11(9), 1750; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091750 - 31 Aug 2021
Viewed by 422
Abstract
Phytomanagement of trace element-contaminated soils combines sustainable soil remediation with the use of plant biomass for different applications. Consequently, phytostabilization using plant species useful for bioenergy production has recently received increasing attention. However, the water requirement of most of these species is a [...] Read more.
Phytomanagement of trace element-contaminated soils combines sustainable soil remediation with the use of plant biomass for different applications. Consequently, phytostabilization using plant species useful for bioenergy production has recently received increasing attention. However, the water requirement of most of these species is a limitation for their use under Mediterranean climatic conditions. In this work, eight plant species growing naturally in mine soils contaminated by trace elements were evaluated for their use as bioenergy crops using thermochemical (combustion) and biochemical (anaerobic digestion) methods. The higher heating values of the biomass of the plants studied were all within a narrow range (16.03–18.75 MJ kg−1), while their biochemical methane potentials ranged from 86.0 to 227.4 mL CH4 (g VS)−1. The anaerobic degradation was not influenced by the presence of trace elements in the plants, but the mineral content (mainly Na) negatively affected the potential thermal energy released by combustion (HHV). The highest annual energy yields from biogas or combustion could be obtained by the cultivation of Phragmites australis and Arundo donax, followed by Piptatherum miliaceum. Both options can be considered to be suitable final destinations for the biomass obtained in the phytostabilization of trace element-contaminated soils and may contribute to the implementation of these remediation techniques in Mediterranean areas. Full article
(This article belongs to the Special Issue New Phytoremediation in Trace Elements Contaminated Soils)
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Article
Hyperaccumulators for Potentially Toxic Elements: A Scientometric Analysis
Agronomy 2021, 11(9), 1729; https://0-doi-org.brum.beds.ac.uk/10.3390/agronomy11091729 - 29 Aug 2021
Viewed by 655
Abstract
Phytoremediation is an effective and low-cost method for the remediation of soil contaminated by potentially toxic elements (metals and metalloids) with hyperaccumulating plants. This study analyzed hyperaccumulator publications using data from the Web of Science Core Collection (WoSCC) (1992–2020). We explored the research [...] Read more.
Phytoremediation is an effective and low-cost method for the remediation of soil contaminated by potentially toxic elements (metals and metalloids) with hyperaccumulating plants. This study analyzed hyperaccumulator publications using data from the Web of Science Core Collection (WoSCC) (1992–2020). We explored the research status on this topic by creating a series of scientific maps using VOSviewer, HistCite Pro, and CiteSpace. The results showed that the total number of publications in this field shows an upward trend. Dr. Xiaoe Yang is the most productive researcher on hyperaccumulators and has the broadest international collaboration network. The Chinese Academy of Sciences (China), Zhejiang University (China), and the University of Florida (USA) are the top three most productive institutions in the field. China, the USA, and India are the top three most productive countries. The most widely used journals were the International Journal of Phytoremediation, Environmental Science and Pollution Research, and Chemosphere. Co-occurrence and citation analysis were used to identify the most influential publications in this field. In addition, possible knowledge gaps and perspectives for future studies are also presented. Full article
(This article belongs to the Special Issue New Phytoremediation in Trace Elements Contaminated Soils)
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