Inhibition of phosphate sorptions on four soil colloids by two bacteria

In soil science the fraction of colloids in soils is understood as particles with diameters smaller than 2μm. Clay minerals, aquoxides of iron and manganese, humic substances, and other polymeric materials are found in this fraction. The spatial arrangement (microstructure) is controlled by the substantial structure of the colloids, by the chemical composition of the soil solution, and by thesoil biota. This microstructure determines among other things the diffusive mass flow within the soils and as a result the availability of substances for chemical and microbiological reactions. The turnover of nutrients, the adsorption of toxicants and the weathering of soil clay minerals are examples of these surface mediated reactions. Due to their high specific surface area, the soil colloids are the most reactive species in this respect. Under the chemical conditions in soils, these minerals are associated in larger aggregates. The accessibility of reactive sites for these reactions on the surface of the colloids is reduced by this aggregation. To determine the turnover rates of chemicals within these aggregates it is highly desirable to visualize directly these aggregation phenomena.

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The Significance of Air Adsorption by Soil Colloids in Picnometric Measurements

Soil Science Society of America Journal ◽

10.2136/sssaj1953.03615995001700010003x ◽

1953 ◽

Vol 17 (1) ◽

pp. 17-19 ◽

Cited By ~ 2

Author(s):

Vernon C. Jamison

Keyword(s):

Soil Colloids

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Removal of PCR inhibiting substances in sewage sludge amended soil

Water Science & Technology ◽

10.2166/wst.1995.0633 ◽

1995 ◽

Vol 31 (5-6) ◽

pp. 311-315 ◽

Cited By ~ 2

Author(s):

Timothy M. Straub ◽

Ian L. Pepper ◽

Charles P. Gerba

Keyword(s):

Cell Culture ◽

Enteric Viruses ◽

Treatment Method ◽

Cytopathic Effects ◽

Chelex 100 ◽

Beef Extract ◽

Polymerase Chain ◽

Seminested Pcr ◽

Soil Colloids ◽

Amended Soil

Current methods for the detection of enteric viruses in soil involve elution of viruses from soil colloids using beef extract or other proteins. These eluates are then assayed in cell culture and observed daily for cytopathic effects (CPE). While this method is suitable for detection of enteric viruses by cell culture, these eluates contain humic acids and heavy metals that interfere with polymerase chain reaction (PCR) detection. Using beef extract eluates prepared from sludge amended soil, 10 different methods of eluate purification were evaluated for their ability to remove PCR inhibition and maximize sensitivity. The treatment method providing the greatest sensitivity of poliovirus detection by PCR was the combination of Sephadex G-50 and Chelex-100. Using this method 2 plaque forming units (PFU) could be detected after reverse transcription and 30 cycles of PCR. Thirty (30) cycles of seminested PCR were performed on these samples to verify nucleic acid sequences and increase sensitivity after the first 30 cycles of PCR. Using seminested PCR, sensitivity of detection using the Sephadex G-50 and Chelex-100 treatment method to 0.2 PFU. In addition to providing excellent sensitivity for viruses in sludge amended soils, this treatment method is relatively simple compared to other methods.

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Release of soil colloids increase the PFAS concentration from saturated soil during flow interruption

Environmental Pollution ◽

10.1016/j.envpol.2021.117297 ◽

2021 ◽

pp. 117297

Author(s):

Annesh Borthakur ◽

Brian K. Cranmer ◽

Gregory P. Dooley ◽

Jens Blotevogel ◽

Shaily Mahendra ◽

...

Keyword(s):

Saturated Soil ◽

Flow Interruption ◽

Pfas Concentration ◽

Soil Colloids

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Retention of the Antibiotic Cefuroxime onto Agricultural and Forest Soils

Applied Sciences ◽

10.3390/app11104663 ◽

2021 ◽

Vol 11 (10) ◽

pp. 4663

Author(s):

Raquel Cela-Dablanca ◽

Carolina Nebot ◽

Lucia Rodríguez López ◽

David Ferández-Calviño ◽

Manuel Arias-Estévez ◽

...

Keyword(s):

Forest Soils ◽

Linear Models ◽

Agricultural Soils ◽

Organic Matter Content ◽

Matter Content ◽

Batch Type ◽

Exchangeable Ca ◽

Influence Of Ph ◽

Best Fit ◽

Soil Colloids

Antibiotics in wastewater, sewage sludge, manures, and slurries constitute a risk for the environment when spread on soils. This work studies the adsorption and desorption of the antibiotic cefuroxime (CFX) in 23 agricultural and forest soils, using batch-type experiments. Our results show that the adsorption values were between 40.75 and 99.57% in the agricultural soils, while the range was lower (from 74.57 to 93.46%) in forest soils. Among the Freundlich, Langmuir, and Linear models, the Freundlich equation shows the best fit for the adsorption results. In addition, agricultural soils with higher pH are the ones that present the highest adsorption. Further confirmation of the influence of pH on adsorption is given by the fact that Freundlich’s KF parameter and the Linear model Kd parameter shows a positive correlation with pH and with the exchangeable Ca and Mg values, which are known to affect the charges of the soil colloids and the formation of cationic bridges between adsorbents and adsorbate. In addition, Freundlich’s n parameter shows a positive and significant correlation with the organic matter content, related to the high adsorption taking place on forest soils despite their pH < 5. Regarding desorption, in most cases, it is lower than 1%, which indicates that CFX is adsorbed in a rather irreversible way onto these soils. Overall, these results can be considered relevant regarding their potential impact on environmental quality and public health.

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EFFECT OF NONCLASSICAL POLARIZATION OF Na+ AND K+ ON THE STABILITY OF SOIL COLLOIDAL PARTICLES IN SUSPENSION

Surface Review and Letters ◽

10.1142/s0218625x18500191 ◽

2017 ◽

Vol 24 (07) ◽

pp. 1850019

Author(s):

DING WU-QUAN ◽

HE JIA-HONG ◽

WANG LEI ◽

LIU XIN-MIN ◽

LI HANG

Keyword(s):

Negative Pressure ◽

Colloidal Particles ◽

Ion Concentration ◽

Electrostatic Repulsion ◽

Adjacent Soil ◽

Net Pressure ◽

The Stability ◽

Two Stages ◽

Soil Colloids ◽

Total Average

The study of soil colloids is essential because the stability of soil colloidal particles are important processes of interest to researchers in environmental fields. The strong nonclassical polarization of the adsorbed cations (Na[Formula: see text] and K[Formula: see text] decreased the electric field and the electrostatic repulsion between adjacent colloidal particles. The decrease of the absolute values of surface potential was greater for K[Formula: see text] than for Na[Formula: see text]. The lower the concentration of Na[Formula: see text] and K[Formula: see text] in soil colloids, the greater the electrostatic repulsion between adjacent colloidal particles. The net pressure and the electrostatic repulsion was greater for Na[Formula: see text] than for K[Formula: see text] at the same ion concentration. For K[Formula: see text] and Na[Formula: see text] concentrations higher than 50[Formula: see text]mmol L[Formula: see text] or 100 mmol L[Formula: see text], there was a net negative (or attractive) pressure between two adjacent soil particles. The increasing total average aggregation (TAA) rate of soil colloids with increasing Na[Formula: see text] and K[Formula: see text] concentrations exhibited two stages: the growth rates of TAA increased rapidly at first and then increased slowly and eventually almost negligibly. The critical coagulation concentrations of soil colloids in Na[Formula: see text] and K[Formula: see text] were 91.6[Formula: see text]mmol L[Formula: see text] and 47.8[Formula: see text]mmol L[Formula: see text], respectively, and these were similar to the concentrations at the net negative pressure.

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