November 24, 2009

(This blog is the second in a series on the Ontario Environment Minister’s Annual Report on Drinking Water for 2009.)

A brief reference to Microbial Source Tracking appears in the Annual Report on Drinking Water released last week by Ontario’s Minister of the Environment.

In a section entitled Emerging Drinking Water Issues, the report states: “We are using the latest research to understand potentially harmful pathogens and chemical pollutants in source water…. Microbial Source Tracking could help scientists distinguish between microorganisms that originate from different fecal sources.”

This rather unobtrusive comment refers to remarkable new technologies that enable researchers to identify whether, for instance, E. Coli in a lake water sample comes from a leaking septic tank, runoff from a farmer’s field on which manure has been spread, a flock of geese, or pet droppings on the beach. “DNA fingerprinting” could play a key role in determining how best to curb the pollution that is fouling waters and closing beaches. It has the potential to take the guess-work out of pollution control and to stop the buck-passing that is now so common (with farmers pointing to sewage systems as major polluters, and municipalities in turn blaming ducks).

Researchers recently identified agriculture as the dominant source of E. coli in southeastern Lake Huron. In an article published in the March 2009 issue of the Canadian Journal of Microbiology, researchers from the University of Guelph and Ontario’s Environment Ministry described their analysis of samples taken between Goderich and Kincardine in 2005 and 2006. They identified the DNA of E. coli in the samples, finding that between 59 and 62 percent of the E. coli came from agriculture. Between five and 14 percent of the E. coli came from wildlife. Just two to three percent came from human waste.