School Of Environment And Earth Sciences

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Subject: search.filters.subject.Heavy metal

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    Plant-microbe association to improve phytoremediation of heavy metal
    (Elsevier, 2022-08-05T00:00:00) Hansda, Arti; Kisku, Prem Chand; Kumar, Vipin; Anshumali
    Urge of development through industrialization has led to disturbance/misbalance of the ecosystem by the release of various contaminants (heavy metals, metalloids, organic pollutants, dyes, etc.). Unlike organic contaminants, heavy metals and metalloids pose a serious threat to the flora and fauna of the surroundings due to their immutable nature. The high cost and nonecofriendly nature of physicochemical methods used for heavy metal removal lead to the innovation of the biological technique �bioremediation.� Phytoremediation is one of the bioremediation methods which use accumulator/hyperaccumulator plants for heavy metal removal from soil, sediments, or water. The phytoremediation process by using plants only is time-consuming and may result in reduced metal uptake in high levels of pollutants. High pollutant concentration may result in toxicity to the plants used for remediation purposes. This situation may be overcome by the plant-microbe association, which will result in improved plant growth and heavy metal sequestration. Various rhizospheric processes are responsible for heavy metal removal by secretion of root exudates (siderophores, carboxylic acid ions) and phytohormones, which affect the mobile and bioavailable form of heavy metals. The plant-microbe association may help in enhancing or reducing the mobility and bioavailability of heavy metal, as well as result in improved plant growth, which could result in a significant speedup of the phytoremediation process. This review enlightens the role of plant growth-promoting bacteria (PGPB) in the acceleration of phytoremediation. The metal uptake mechanisms are also discussed. � 2022 Elsevier Inc. All rights reserved.
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    Recycling of lignocellulosic waste as vermicompost using earthworm Eisenia fetida
    (Springer, 2019) Sharma, K; Garg, V.K.
    Present study aimed to evaluate the vermicomposting of lignocellulosic wastes employing Eisenia fetida earthworms. The study examined the effectiveness of vermicomposting for 105 days by mixing lignocellulosic waste (LW) with cattle manure (CM) in five different proportions. Results revealed that TOC and C/N ratio decreased gradually till end and in vermicomposts varied between 268–320 g/kg and 12.26–16.85, respectively. Nutrient content (NPK) in the vermicomposts increased with time in all the mixtures. Heavy metals’ content also increased in vermicomposts and benefit ratio for heavy metals ranged between 0.06 and 5.1. Increase in earthworm biomass (22.38–39.64 g) and reproduction (21.27–31.60 hatchlings/worm) was also satisfactory in all the waste mixtures. Based on results, it can be inferred that lignocellulosic waste can successfully be converted into good quality manure employing earthworms. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
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    Biotransformation of bakery industry sludge into valuable product using vermicomposting
    (Elsevier, 2019) Yadav, A; Garg, V.K.
    The aim of present work was to evaluate periodic changes in bakery industry sludge during vermicomposting. Six different blends of cow dung (CD) and bakery industry sludge (BIS) containing 10 to 50% of BIS were assessed in this study. Changes in physico-chemical parameters were evaluated at 21 days interval up to 105 days. Earthworms significantly increased NPK content and EC, while decreased pH, TOC and C: N ratio of BIS. After vermicomposting, TKN, TAP and TK contents increased 2.0–3.5, 1.2–1.9 and 1.2–1.4 times, respectively as compared to initial blends. A significant reduction (65.4–83.5%) in C: N ratio was observed in all blends. The concentrations of metals were found to be higher in the vermicomposts as compared initial blends. It was inferred that bakery industry sludge spiked with cow dung can be biotransformed into valuable manure employing earthworms. © 2018 Elsevier Ltd