Transport of Escherichia coli through soil / by Bruce Rosa.
Rosa, Bruce A.
SubjectEscherichia coli Dispersal
Pathogenic microorganisms Dispersal
Clay soils Environmental aspects
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"Sorption is an important process in the retention of pathogens by clay barriers. Batch sorption experiments were conducted to investigate the sorption of nonpathogenic 'E. coli' to illite, kaolinite, and montmorillonite clays, a natural red clay, a silt and a sand. The Freundlich isotherm model provides the best fit for the sorption data. The sorptive capacity (SC) of each soil for 'E. coli' was calculated at an equilibrium ' E. coli' concentration of 1 x 108 CFU/mL. The SC values correlate strongly with the measured cation exchange capacity (having an R 2 of 0.92), as well as the weighted average particle size (having an R2 of 0.83), of the soils. Columns of compacted and normally consolidated high plastic clay and compacted non-plastic silt soils were exposed to cycles of freezing and thawing to simulate conditions of physical weathering, in turn creating a fracture network in the specimens.