Microbial Source Tracking In Rural And Urban Watersheds

Identifying and managing microbial water quality at the watershed scale is extremely challenging. There are usually multiple sources of fecal microorganisms, distributed over large geographic areas, and levels of indicator organisms and pathogens are highly variable and dependant on a number of hydrological, biophysical and anthropogenic factors.  Developing the ability to fully characterize human health risks, and identify sources of microbial loading, requires additional tools.

In recent years, a number of different types of molecular approaches have been developed for the purpose of tracking sources of fecal bacteria within water systems.  In particular, library-independent methods based on 16s rRNA gene PCR primers  developed for the Bacteroidales order are gaining interest. These tools show great promise for identifying the source and relative magnitude of fecal bacteria loading at watershed scales, but they require further validation and testing on a watershed by watershed basis. The primary objectives of this research program are to:

  1. Assess the persistence and genetic diversity of Escherichia coli in soil, groundwater and surface water environments, and usefulness of E coli as a fecal indicator organism
  2. Identify and evaluate alternative fecal indicator organisms and microbial source tracking tool, such as Bacteroidales genetic markers
  3. Assess the presence of pathogenic microorganisms in both urban and rural watersheds, and their relationships with fecal indicator organisms

Within this research program field studies are currently being conducted within several watersheds throughout Nova Scotia including the Cornwallis River Watershed, the Musquodoboit River Watershed, and the Shubenacadie River Headwaters Watershed.  This work is funded through an NSERC Strategic Grant, the Canadian Water Network, Nova Scotia Environment and Halifax Water.