Submitted to: American Geophysical Union
Publication Type: Proceedings
Publication Acceptance Date: March 15, 2004
Publication Date: May 17, 2004
Citation: Guber, A.K., Pachepsky, Y.A., Shelton, D.R. 2004. Transport and retention of E. coli in saturated well-structured soil. American Geophysical Union, May 17-21, 2004, Montreal, Canada. Paper #3112.
Manure is a source of several bacterial pathogens that can potentially contribute to surface and ground water contamination. We hypothesized that manure could enhance bacteria survival, and manure particulates could compete for soil adsorption sites and serve as carriers. The objective of this work to compare chloride, E. Coli, and manure colloid breakthrough in soil. The pulse of bovine manure solution containing E. coli bacteria and KCl was passed through saturated undisturbed 20-cm columns from the A horizon of clay loam soil at 9 C during 10 days. Equilibrium attachment of E. coli to soil was measured in batch experiments. Attachment of E. coli to soil was much smaller in presence of manure, and decreased with the increase in manure contents. Maximum bacteria and chloride effluent concentrations were observed before and after the first pore volume of soil solution has been displaced with the influent, respectively. From 1\% to 3\% of the total applied bacteria were found in pore solution, and from 5\% to 18\% were attached to soil particles after the transport experiment. Individual columns had different average water flow velocities ranging from 2.3 to 9.3 cm/day. E. coli transport was similar to manure transport at low velocity during the whole experiment. Bacteria and manure breakthrough curves had much longer tails compared with chloride. Overall, an increase in flow velocity decreased attachment and entrapment of manure and bacteria in pore space. Variability in flow velocity and its effects on E. coli and manure transport were caused by different macroporosity in individual columns of the soil.