Pathogen and indicator variability in a heavily impacted watershed.

Water samples were collected from 36 locations within the Grand River Watershed, in Southwestern Ontario, Canada from July 2002 to December 2003 and were analyzed for total coliforms, fecal coliforms, Escherichia coli, Escherichia coli O157:H7, and thermophilic Campylobacter spp. A subset of samples was also analyzed for Cryptosporidium spp., Giardia spp.

Assessing levels of pathogenic contamination in a heavily impacted river used as a drinking-water source.

This paper describes initial results from a research program that aims to gain greater understanding of sources of pathogens and the environmental factors that influence their survival and transport in watersheds. An additional goal is to enhance the ability to predict potential levels of pathogenic microorganisms arriving at drinking-water treatment plant intakes. The objectives will be supported by an intensive monitoring program examining the temporal and spatial variability of pathogens in a test watershed (the Grand River Watershed, Ontario).