/AnMtgsAbsts2009.53310 Contaminant Bacteria in Soils; From Transport to Survival and the Indicator of the Indicator.

Wednesday, November 4, 2009: 1:20 PM
Convention Center, Room 401, Fourth Floor

Adrian Unc1, Michael Goss2, Mohammad R. Mosaddeghi3, Joanna Passmore4, Susan V. Springthorpe5, Sigen Chen6, A.A. Mahboubi3 and Syed A. Sattar5, (1)New Mexico State Univ., Las Cruces, NM
(2)Kemptville Campus, Univ. of Guelph, Kemptville, ON, Canada
(3)Department of Soil Science, Bu-Ali Sina Univ., Hamadan, Iran
(4)Earth and Environmental Sciences, Univ. of Waterloo, Waterloo, ON, Canada
(5)Centre for Research on Evironmental Microbiology, Univ. of Ottawa, Ottawa, ON, Canada
(6)Land Resource Science, Univ. of Guelph, Guelph, ON, Canada
Fecal microbial contamination risk to water resources is determined by many factors. Perception of such risk to the same water resources is often dependent on the experimental approach and the scope of the interpretation of experimental results.
Particulate transport through heterogeneous porous media, such as soils, is clearly a function of the pore geometry and the stability of this geometry.
Addition colloidal and particulate mixes, as organic wastes are, may alter the functional parameters of the intrinsic soil geometry and thus affect flow of water-associated contaminants. Transport of charged microbial particles, must be interpreted in the context of the charge interactions within the soil solution as they are affected by soil parameters and the charge properties imparted to the soil/water system by the addition of soluble and colloidal matter in organic wastes.
Persistence of microbial contamination risks to soils and adjacent water systems is dependent on the survival capability of the species of interest. Survival is obviously species dependent, but affected by variability in the relevant environmental parameters, and how these parameters are affected by management options. The capacity of soils to act as long-term sinks for such indicators may affect our potential to clearly discern immediate risks.
Given the large number of potential microbial contaminants, risk assessment exercises must by cause of expediency, focus on certain indicators. Most often the indicator is Escherichia coli, since it is generally considered to still be the best indicator of fecal contamination, out of a number of imperfect indicators. Nonetheless quantitative and qualitative relation between indicators and contaminants is often variable and dependent on the variable textural and hydrological parameters of soils and relevant management options.
       This presentation highlights information obtained on these various aspects by our group over several years.