Monday, November 13, 2006 - 12:00 PM

Assessing and Managing the Risk to Water from Bugs and Drugs.

Ed Topp1, Bonnie Ball Coelho1, Patrick Duriez1, Tom Edge2, Vic Gannon3, David Lapen1, Lu Zexun1, Emilie Lyautey1, Diane Medeiros4, Norman Neumann5, Michael Payne6, Will Robertson4, and Norma Ruecker5. (1) Agriculture and Agri-Food Canada, London, ON N5V 4T3, Canada, (2) National Water Research Institute, Environment Canada, Burlington, ON L7R 4A6, Canada, (3) Laboratory for Foodborne Zoonoses, Health Canada, Lethbridge, AB T1J 3Z4, Canada, (4) Health Canada, Ottawa, ON K1A 0K9, Canada, (5) Alberta Provincial Laboratory for Public Health, Calgary, AB T2N 4W4, Canada, (6) Ontario Ministry of Agriculture, Food and Rural Affairs, Stratford, ON N5A 5T8, Canada

Manures are an important source of crop nutrients, yet their use has to be managed appropriately to protect water resources from contaminants that can pose a risk to human or environmental health. In this context, we have undertaken three avenues of investigation to obtain information that will better inform an understanding of risk, and the development of better management practices for manure use. First, by means of microbial source tracking methods, we are evaluating the relative significance of agricultural, human, and wildlife fecal inputs into surface water. Biological endpoints of interest include a variety of indicator (E. coli, Enterococcus spp., Bacteroides-Prevotella) and pathogenic (Salmonella, Campylobacter spp., E. coli 0157:H7, Listeria monocytogenes) bacteria, and Cryptosporidium spp. A variety of phenotypic and genotypic microbial source tracking methods are being deployed to evaluate the characteristics and likely sources of these organisms in surface waters of three watersheds that vary widely in their land use activities. Secondly, in many confined animal and livestock production systems, manure is stored for many months prior to release into the broader environment, providing an opportunity to change manure composition significantly. We have been investigating the dynamics of E. coli in commercial swine farms, evaluating how the population structure and antibiotic resistance profiles vary seasonally within the barn, and during static storage of swine manure slurry (SMS). Finally, we have been evaluating application methods and technologies and site-specific considerations for applying SMS to reduce contamination of tilewater drainage by preferential flow at the time of application. Overall, this research will provide insights into the relative significance of agriculture with respect to surface water quality in Canada, and help inform the development of better practices for manure management.