Characterizing Permeability Heterogeneity in Core Samples From Standard Miscible Displacement Experiments

1993 ◽  
Vol 8 (02) ◽  
pp. 112-116
Author(s):  
James E. Houseworth
Keyword(s):  
Miscible Displacement ◽  
Permeability Heterogeneity ◽  
Core Samples ◽  
Displacement Experiments

scholarly journals Glyphosate Transport in Two Louisiana Agricultural Soils: Miscible Displacement Studies and Numerical Modeling

Soil Systems ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 53 ◽  
Author(s):  
Joshua Padilla ◽  
H. Selim
Keyword(s):  
Transport Model ◽  
Agricultural Soils ◽  
Exchange Capacity ◽  
Miscible Displacement ◽  
Soil Environment ◽  
Linear Modeling ◽  
Primary Metabolite ◽  
Aminomethylphosphonic Acid ◽  
Displacement Experiments ◽  
Reaction Transport

Glyphosate (N-(phosphonomethyl) glycine) (GPS) is currently the most commonly used herbicide worldwide, and is generally considered as immobile in soils. However, numerous reports of the environmental occurrence of the herbicide coupled with recent evidence of human toxicity necessitate further investigation as to the behavior of GPS in the soil environment. Batch sorption studies along with miscible displacement experiments were carried out in order to assess the mobility of GPS in two Louisiana agricultural soils; Commerce silt loam and Sharkey clay. Batch results indicated a high affinity of both soils for solvated GPS, with greater affinity observed by the Sharkey soil. GPS sorption in the Commerce soil was most likely facilitated by the presence of amorphous Fe and Al oxides, whereas the high cation exchange capacity of the Sharkey soil likely allows for GPS complexation with surface exchangeable poly-valent cations. Miscible displacement studies indicate that GPS mobility is highly limited in both soils, with 3% and 2% of the applied herbicide mass recovered in the effluent solution from the Commerce and Sharkey soils, respectively. A two-site multi-reaction transport model (MRTM) adequately described GPS breakthrough from both soils and outperformed linear modeling efforts using CXTFIT. Analysis of extracted herbicide residues suggests that the primary metabolite of GPS, aminomethylphosphonic acid (AMPA), is more mobile in both soils, although both compounds are strongly retained.

DENSITY EFFECTS IN MISCIBLE DISPLACEMENT EXPERIMENTS

Soil Science ◽  
1969 ◽  
Vol 107 (5) ◽  
pp. 372-380 ◽  
Author(s):  
H. K. KRUPP ◽  
D. E. ELRICK
Keyword(s):  
Miscible Displacement ◽  
Density Effects ◽  
Displacement Experiments
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