Submitted to: Journal of Environmental Quality
Publication Type: Research notes
Publication Acceptance Date: 9/15/2005
Publication Date: 11/1/2005
Citation: Guber, A.K., Shelton, D.R., Pachepsky, Y.A. 2005. Manure decreases Escherichia coli attachment to soil. Journal of Environmental Quality. 34:2086-2090, DOI: 10.2134/jeq2005.0039. Interpretive Summary: Bacterial transport through soil is substantially affected by attachment to soil particles and straining. Despite the fact that feces/manure are a major source of bacterial inputs to soil, including several human pathogens, little is known about the effects of manure on bacterial attachment to soil. The objective of this work was to assess Escherichia coli, a ubiquitous fecal-borne bacterium, attachment to soil as effected by manure. E. coli was added to a loam and a sandy clay loam soil suspensions containing containing 0, 2000 ppm, or 4000 ppm of a liquid manure solution. After equilibration E. coli attached to soil particles vs. E. coli in in free solution were measured. Manure dramatically affected E. coli attachment to soil. The maximum E. coli attachment occurred in the absence of manure, while Increasing manure content resulted in a substantial decrease in attachment to soil.
Technical Abstract: Attachment of bacteria to soil is an important component of bacterial fate and transport. Escherichia. coli are commonly used as indicators of fecal contamination in the environment. Despite the fact that E. coli are derived exclusively from feces/manure, relatively little is known about the effects of manure on E. coli fate and transport, including attachment to soil. The objective of this work was to evaluate the magnitude of the effect of manure on E. coli attachment to soil. Escherichia coli attachment to soil was studied in batch experiments with samples of loam and sandy clay loam topsoil that were taken in Pennsylvania and Maryland. E. coli cells were added to the water-manure suspensions containing 0, 2000 ppm, and 4000 ppm of filtered liquid bovine manure, which subsequently were equilibrated with air-dry sieved soil in different soil-suspension ratios. Langmuir isotherm equation was fitted to data. Manure dramatically affected E. coli attachment to soil. Attachment isotherms were closer to linear without manure and were strongly non-linear in presence of manure. The maximum E. coli attachment occurred in the absence of manure. Increasing manure content generally resulted in decreased attachment.