Nano-oxides immobilize Cd, Pb, and Zn in mine spoils and contaminated soils facilitating plant growth

2021 ◽  
Author(s):  
Srimathie Priyanthika Indraratne ◽  
Gary M. Pierzynski ◽  
Lucas R. Baker ◽  
P. V. Vara Prasad
Keyword(s):  
Plant Growth ◽  
Contaminated Soils ◽  
High Reactivity ◽  
Mine Spoils ◽  
Linear Isotherm ◽  
Nutrient Supplements ◽  
Zn Concentration ◽  
Plant Emergence ◽  
Soil Metal ◽  
Sorghum Bicolor L

Nanoparticles with high reactivity can be applied as amendments to remediate soil metal contaminations by immobilizing toxic elements. Nano-oxides of Fe have been studied but Al and Ti nano-oxides have not been tested for their remediation capacity of toxic metals. The potential of synthesized iron (Fe-O), aluminum (Al-O), and titanium (Ti-O) nano-oxides for stabilizing Cd, Pb, and Zn in mine spoil (Chat) and contaminated soil was compared using adsorption studies and a greenhouse experiment. Chat and soil were amended with nano oxides at two rates (25 and 50 g kg-1) and a pot experiment was conducted with sorghum (Sorghum bicolor L. Moench). Leachates were collected twice per week from plant emergence to harvest at maturity and metals were compared against an unamended control. Chat was contaminated with Cd, Pb, and Zn at 84, 1583, and 6154 mg kg-1, and soil at 15, 1260, and 3082 mg kg-1, respectively. Adsorption conformed to the Langmuir linear isotherm and adsorption maxima of metals were in the order of Al-O > Ti-O ≥ Fe-O. Nano-oxides reduced Cd concentration by 28% (Fe-O) to 87% (Ti-O) and Zn concentration by 14% (Fe-O) to 85% (Al-O) in plant tissues compared with unamended Chat. Nano-oxides significantly reduced Cd, Pb, and Zn in leachates and available Cd and Zn in Chat/ soil relative to the respective unamended controls. Nano-oxides can be used to remediate heavy metal contaminated Chat and soil and facilitate plant growth under proper nutrient supplements. Nano-oxides of Al-O and Ti-O remediated metals more effectively than Fe-O

scholarly journals Role of Two Plant Growth-Promoting Bacteria in Remediating Cadmium-Contaminated Soil Combined with Miscanthus floridulus (Lab.)

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 912
Author(s):  
Shuming Liu ◽  
Hongmei Liu ◽  
Rui Chen ◽  
Yong Ma ◽  
Bo Yang ◽  
...  
Keyword(s):  
Plant Growth ◽  
Contaminated Soils ◽  
Translocation Factor ◽  
Plant Growth Promoting Bacteria ◽  
Bacterial Strains ◽  
Pgp Traits ◽  
Cd Tolerance ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Cd Translocation

Miscanthus spp. are energy plants and excellent candidates for phytoremediation approaches of metal(loid)s-contaminated soils, especially when combined with plant growth-promoting bacteria. Forty-one bacterial strains were isolated from the rhizosphere soils and roots tissue of five dominant plants (Artemisia argyi Levl., Gladiolus gandavensis Vaniot Houtt, Boehmeria nivea L., Veronica didyma Tenore, and Miscanthus floridulus Lab.) colonizing a cadmium (Cd)-contaminated mining area (Huayuan, Hunan, China). We subsequently tested their plant growth-promoting (PGP) traits (e.g., production of indole-3-acetic acid, siderophore, and 1-aminocyclopropane-1-carboxylate deaminase) and Cd tolerance. Among bacteria, two strains, Klebsiella michiganensis TS8 and Lelliottia jeotgali MR2, presented higher Cd tolerance and showed the best results regarding in vitro growth-promoting traits. In the subsequent pot experiments using soil spiked with 10 mg Cd·kg−1, we investigated the effects of TS8 and MR2 strains on soil Cd phytoremediation when combined with M. floridulus (Lab.). After sixty days of planting M. floridulus (Lab.), we found that TS8 increased plant height by 39.9%, dry weight of leaves by 99.1%, and the total Cd in the rhizosphere soil was reduced by 49.2%. Although MR2 had no significant effects on the efficiency of phytoremediation, it significantly enhanced the Cd translocation from the root to the aboveground tissues (translocation factor > 1). The combination of K. michiganensis TS8 and M. floridulus (Lab.) may be an effective method to remediate Cd-contaminated soils, while the inoculation of L. jeotgali MR2 may be used to enhance the phytoextraction potential of M. floridulus.

scholarly journals Efficacy of Indole Acetic Acid and Exopolysaccharides-Producing Bacillus safensis Strain FN13 for Inducing Cd-Stress Tolerance and Plant Growth Promotion in Brassica juncea (L.)

2021 ◽  
Vol 11 (9) ◽  
pp. 4160
Author(s):  
Farheen Nazli ◽  
Xiukang Wang ◽  
Maqshoof Ahmad ◽  
Azhar Hussain ◽  
Bushra ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Plant Growth ◽  
Stress Tolerance ◽  
Brassica Juncea ◽  
Contaminated Soils ◽  
Effective Strain ◽  
Antioxidant Enzyme Activities ◽  
Cd Stress ◽  
Cd Accumulation ◽  
Bacillus Safensis

Untreated wastewater used for irrigating crops is the major source of toxic heavy metals and other pollutants in soils. These heavy metals affect plant growth and deteriorate the quality of edible parts of growing plants. Phytohormone (IAA) and exopolysaccharides (EPS) producing plant growth-promoting rhizobacteria can reduce the toxicity of metals by stabilizing them in soil. The present experiment was conducted to evaluate the IAA and EPS-producing rhizobacterial strains for improving growth, physiology, and antioxidant activity of Brassica juncea (L.) under Cd-stress. Results showed that Cd-stress significantly decreased the growth and physiological parameters of mustard plants. Inoculation with Cd-tolerant, IAA and EPS-producing rhizobacterial strains, however, significantly retrieved the inhibitory effects of Cd-stress on mustard growth, and physiology by up regulating antioxidant enzyme activities. Higher Cd accumulation and proline content was observed in the roots and shoot tissues upon Cd-stress in mustard plants while reduced proline and Cd accumulation was recorded upon rhizobacterial strains inoculation. Maximum decrease in proline contents (12.4%) and Cd concentration in root (26.9%) and shoot (29%) in comparison to control plants was observed due to inoculation with Bacillus safensis strain FN13. The activity of antioxidant enzymes was increased due to Cd-stress; however, the inoculation with Cd-tolerant, IAA-producing rhizobacterial strains showed a non-significant impact in the case of the activity of superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) in Brassica juncea (L.) plants under Cd-stress. Overall, Bacillus safensis strain FN13 was the most effective strain in improving the Brassica juncea (L.) growth and physiology under Cd-stress. It can be concluded, as the strain FN13 is a potential phytostabilizing biofertilizer for heavy metal contaminated soils, that it can be recommended to induce Cd-stress tolerance in crop plants.

Integrated phytoremediation system for uranium-contaminated soils by adding a plant growth promoting bacterial mixture and mowing grass

2018 ◽  
Vol 19 (4) ◽  
pp. 1799-1808 ◽  
Author(s):  
Xin Qi ◽  
Xichao Hao ◽  
Xiaoming Chen ◽  
Shiqi Xiao ◽  
Shilin Chen ◽  
...  
Keyword(s):  
Plant Growth ◽  
Contaminated Soils ◽  
Plant Growth Promoting ◽  
Growth Promoting

The effects of replaced topsoil of different depths on the vegetation and soil properties of reclaimed coal mine spoils in an alpine mining area

2019 ◽  
Vol 65 (3-4) ◽  
pp. 92-105
Author(s):  
Xinguang Yang ◽  
Xilai Li ◽  
Mingming Shi ◽  
Liqun Jin ◽  
Huafang Sun
Keyword(s):  
Plant Growth ◽  
Soil Properties ◽  
Coal Mine ◽  
Growth Parameters ◽  
Soil Depth ◽  
Mining Area ◽  
Vegetation Coverage ◽  
Mine Spoils ◽  
Plant Soil ◽  
Different Depths

Replacement of topsoil to an appropriate depth is one of the key methods for ecological restoration. The objective of this study was to investigate the effects of topsoil replacement depth on vegetation and soil properties, and to identify the optimum soil depth for reclamation of coal mine spoils in a cold alpine mining area. We sowed 3 herbaceous species after coal mine spoil heaps were treated with topsoil to 3 depths (0, 20‒25, 40‒45 cm). The variations in vegetation community structure, plant growth, soil properties were measured at different replaced topsoil depths. The correlations between plant and soil properties were analyzed statistically. The results showed species richness, diversity and evenness were not significantly different among different depths of topsoil (P > 0.05). Vegetation coverage, density, height and aboveground biomass increased significantly (P < 0.05) with increasing topsoil depth. Soil properties did not change significantly with increasing topsoil depth (P > 0.05), but soil organic matter was significantly higher at 40‒45 cm topsoil depth than at other two depths (P < 0.05). All soil properties, with the exception of total potassium, were positively correlated with the plant growth parameters. The 40‒45 cm topsoil depth of replacement should be considered as effective method in reclaiming coal mine spoils. The use of both topsoil replacement to a depth of 40‒45 cm and sowing of suitable herbaceous seeds is found to be an effective restoration strategy. Additionally, fertilization might be used as a substitute for artificial topsoil replacement to improve soil quality and speed up revegetation process by the positive plant-soil interactions.

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