scholarly journals Steam treatment of contaminated groundwater aquifers – development of pathogenic micro-organisms in soil

2005 ◽  
Vol 7 ◽  
pp. 37-40
Author(s):  
Carsten Suhr Jacobsen ◽  
Susanne Elmholt ◽  
Carsten Bagge Jensen ◽  
Pia Bach Jakobsen ◽  
Mikkel Bender
Keyword(s):  
Microbial Community ◽  
Microbial Activity ◽  
Environmental Protection Agency ◽  
Steam Injection ◽  
Vapour Phase ◽  
Steam Treatment ◽  
Deep Aquifer ◽  
Vacuum Suction ◽  
Water Saturated ◽  
Micro Organisms

Steam treatment of contaminated soil and aquifer sediment is a promising method of cleaning soil. The treatment is based on steam injection into a water saturated porous aquifer (Gudbjerg et al. 2004), by which the heat transfers the contaminants into the vapour phase, allowing entrapment in an active carbon filter connected to a large vacuum suction device. The treatment is effective against several important groundwater contaminants, including pentachlorophenole and perchloroethylene, typically found in association with industrial processes or dry cleaning facilities. Furthermore, as an example of removal of non-aqueous phase liquids (NAPLs) large amounts of creosote have been recovered after steam injection in a deep aquifer (Kuhlmann 2002; Tse & Lo 2002). Steam treatment is dependent on the complete heating of the soil volume under treatment. The steam has a strongly adverse impact on trees and other plants with deep root systems within the soil, but no other visible effects have been reported. The aim of the activities undertaken during collaborative projects carried out by the Geological Survey of Denmark and Greenland (GEUS) and the Danish Institute of Agricultural Sciences (DJF) for the Danish Environmental Protection Agency and the local authorities in Copenhagen (Københavns Amt) was to establish to what extent the microbial community was affected by the steam treatment of the soil. A few results from the literature indicate that the microbial activity increases in steam treated soil (Richardson et al. 2002), probably due to microbial degradation of the soil contaminants in combination with microbial utilisation of heatkilled organisms. It is, however, not known whether this increased microbial activity is associated with the development of pathogenic micro-organisms; these are typically able to grow at higher temperatures than the general microbial community in soil.

scholarly journals Detecting Redox Potentials Using Porous Boron Nitride/ATP-DNA Aptamer/Methylene Blue Biosensor to Monitor Microbial Activities

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 83
Author(s):  
Kai Guo ◽  
Zirui Song ◽  
Gaoxing Wang ◽  
Chengchun Tang
Keyword(s):  
Methylene Blue ◽  
Microbial Community ◽  
Boron Nitride ◽  
Redox Potential ◽  
Microbial Activity ◽  
Potential Change ◽  
Dna Aptamer ◽  
Redox Potentials ◽  
Microplate Reader

Microbial activity has gained attention because of its impact on the environment and the quality of people’s lives. Most of today’s methods, which include genome sequencing and electrochemistry, are costly and difficult to manage. Our group proposed a method using the redox potential change to detect microbial activity, which is rooted in the concept that metabolic activity can change the redox potential of a microbial community. The redox potential change was captured by a biosensor consisting of porous boron nitride, ATP-DNA aptamer, and methylene blue as the fluorophore. This assembly can switch on or off when there is a redox potential change, and this change leads to a fluorescence change that can be examined using a multipurpose microplate reader. The results show that this biosensor can detect microbial community changes when its composition is changed or toxic metals are ingested.

scholarly journals Phytochemical Screening and Biological Studies of Shilajit (Asphaltum)

2017 ◽  
Vol 9 (1) ◽  
pp. 15
Author(s):  
Shahid Aziz ◽  
Sidra Khaliq ◽  
Habib Ur-Rehman ◽  
Kh. Shakeel Ghani ◽  
Muhammad Irshad ◽  
...  
Keyword(s):  
Microbial Activity ◽  
Cardiac Glycosides ◽  
Reducing Sugars ◽  
Phytochemical Analysis ◽  
Phytochemical Screening ◽  
Bacterial Strains ◽  
Biological Studies ◽  
Dead Plant ◽  
Micro Organisms

<p>Shilajit (asphaltum)  is produced  by the long term humification  of dead plant material  and organic vegetable matter  by different micro-organisms and has great potential for the treatment of a variety of human conditions.  This treatise reviews its origin, sources, chemical composition, biological  and  commercial importance. Phytochemical analysis was done by standard methods to evaluate  different Shilajit (asphaltum) classes of compounds in different samples of shilajit  which are responsible for their  biological activity.  Shilajit`s anti-microbial activity has been evaluated  against four different bacterial strains viz., <em>Escherichia coli, Psuedomonas aeuroginosa</em>, <em>Klebisella pneumonia</em> and <em>Staphylococcus aureus. </em>Phytochemical analysis illustrated  that shilajit contains  terpenoids, cardiac glycosides, saponins and reducing sugars. Surprisingly,  some classes of compounds are absent in shilajit  viz., alkaloids, flavonoids, tannins and anthraquinones. . Shilajit showed no response towards halophytic bacteria and  negligible activity was shown towards other strains of bacteria. Since   anti-microbial activity is based on environmental factors  its activity varied  between locations.</p>

scholarly journals Soil Microbial Community Changes in a Field Treatment with Chlorotoluron, Flufenacet and Diflufenican and Two Organic Amendments

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1166
Author(s):  
María José Carpio ◽  
Carlos García-Delgado ◽  
Jesús María Marín-Benito ◽  
María Jesús Sánchez-Martín ◽  
María Sonia Rodríguez-Cruz
Keyword(s):  
Microbial Community ◽  
Microbial Biomass ◽  
Microbial Activity ◽  
Soil Microbial Community ◽  
Organic Amendments ◽  
Herbicide Application ◽  
Amended Soils ◽  
Soil Microbial ◽  
Unamended Soil ◽  
Over Time

The soil microbial activity, biomass and structure were evaluated in an unamended (S) and organically amended soil treated with two commercial formulations of the herbicides chlorotoluron (Erturon®) and flufenacet plus diflufenican (Herold®) under field conditions. Soils were amended with spent mushroom substrate (SMS) or green compost (GC). Soil microbial dehydrogenase activity (DHA), biomass and structure determined by the phospholipid fatty acid (PLFA) profiles were recorded at 0, 45, 145, 229 and 339 days after herbicide treatment. The soil DHA values steadily decreased over time in the unamended soil treated with the herbicides, while microbial activity was constant in the amended soils. The amended soils recorded higher values of concentrations of PLFAs. Total soil microbial biomass decreased over time regardless of the organic amendment or the herbicide. Herbicide application sharply decreased the microbial population, with a significant modification of the microbial structure in the unamended soil. In contrast, no significant differences in microbial biomass and structure were detected in S + SMS and S + GC, untreated or treated with herbicides. The application of SMS and GC led to a significant shift in the soil microbial community regardless of the herbicides. The use of SMS and GC as organic amendments had a certain buffer effect on soil DHA and microbial biomass and structure after herbicide application due to the higher adsorption capacity of herbicides by the amended soils.

Root exudate induced microbial activities and phosphorus cycling in soil: An application of phosphate oxygen isotopes

2020 ◽  
Author(s):  
Sunendra R Joshi ◽  
David H McNear
Keyword(s):  
Microbial Community ◽  
Isotopic Composition ◽  
Oxygen Isotope ◽  
Microbial Activity ◽  
Oxygen Isotopes ◽  
Root Exudate ◽  
Rhizosphere Soil ◽  
Microbial Activities ◽  
Oxygen Isotope Ratios ◽  
P Cycling

&lt;p&gt;Rhizosphere is the most biologically active region between the plant and the surrounding soil where plant release their fixed carbon into the soils. Depending on the availability and types of carbon compounds released from the plant, they can directly solubilize nutrient or indirectly influence nutrient cycling by promoting increased microbial activity in the rhizosphere. In this study we applied phosphate oxygen isotope ratios (d&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;P&lt;/sub&gt;) to determine how root exudate influences temporal variation in microbial activities and P cycling in the rhizosphere. Rhizoboxes were filled with soils, watered to 75% water holding capacity and equilibrated for 10 days. After equilibration labeled phosphate isotopes synthesized using &lt;sup&gt;18&lt;/sup&gt;O labeled water was applied. Then a mixed exudate (i.e., glucose, alanine, and oxalate in the ratio of 1:1:1) was introduced into the soil for 4, 10, and 20 days via an artificial root. We used a sequential extraction technique (i.e., resin-Pi, NaHCO&lt;sub&gt;3&lt;/sub&gt;-P, NaOH-P, and HCl-P) to track the fate of applied P in bulk and rhizosphere soils. The root exudate effects on the rate of P cycling and microbial activity were investigated using phosphate oxygen isotope ratios in the resin-Pi pool. Microbial community structures was determined using phospholipid fatty acids (PLFA) profiles. After supplying root exudate for 4, 10, and 20 days, the results showed that bioavailable P (i.e., resin-Pi) concentration was always higher in the bulk soil compared to rhizosphere soil and originally bioavailable P transformed gradually into unavailable P (i.e., NaOH-P and HCl-P). After supplying exudate compound for 4 days, the applied PO&lt;sub&gt;4&lt;/sub&gt; was mostly in the resin-Pi pool and its isotopic composition was heavier than the equilibrium isotopic composition suggesting that this Pi pool was not completely cycled by the microorganisms. As we continue supplying exudate compounds, the concentration of resin-Pi gradually decreased and as microbial activities increased, its isotopic composition got closer to the equilibrium isotopic composition. Further the microbial community structure in the rhizosphere soil after supply of root exudate were distinctly different then the bulk soil. Using phosphate oxygen isotopes this study shows the influence of root exudates on the rate of P cycling in rhizosphere soils.&lt;/p&gt;

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