Transport and Survival of Pathogenic Bacteria Associated With Dairy Manure in Soil and Groundwater

Background/Need: With over 15,000 dairy farms and 1.2 million cows, the dairy industry is of enormous historical, economical and cultural importance to the State of Wisconsin. Approximately 48 million tons of manure is produced in Wisconsin annually and nearly two-thirds of all farms spread manure immediately on the surrounding fields because of inadequate storage. In recent years, much concern has arisen over the release of human pathogens into the water and food supply due to the land application of manures for crop fertilization, wash water and stormwater runoff. On October 11, 2006, the EPA signed the Ground Water Rule into law, which requires drinking water systems using groundwater sources to monitor for indicator organisms of pathogenic viruses and bacteria from fecal contamination. Knowledge of the factors that affect and facilitate the transport of manure associated pathogens will be critical to making an accurate determination of groundwater vulnerability and providing adequate drinking water treatment to prevent waterborne disease.

Objective: The overall goal of this project was to evaluate the impact of various manure components, e.g., pH, organic matter, nutrients, particulate matter, and potential biofilm growth on the transport and survival characteristics of fecal indicators and pathogenic bacterium E. coli O157:H7. Research objectives focused on determining the relationship between the deposition of indicator organisms E. coli and pathogenic serotype E. coli O157:H7 through well controlled laboratory column studies and examining the interactions between manure suspensions and bacterial strains and their associated transport behavior under different solution chemistry. In addition, the potential of biofilm formation as a result of various manure components and its impact on bacterial attachment and survival mechanisms was investigated.