AWWA WQTC58906

This paper summarizes selected data from a pathogen monitoring program in the Grand River watershed in Southern Ontario, Canada. The indicators/pathogens discussed in the paper include: fecal coliforms, E. coli, E. coli O157:H7, and Campylobacter spp. Data is presented for one year of monitoring. Fecal coliforms were found in 95 to 100% of all samples and E. coli were found in 91 to 100%. Campylobacter was less prevalent but was found in 59 to 85% of all samples nonetheless. E. coli O157:H7 was isolated and confirmed in a five-step process. While the "presumptive" tests showed that it may be present in 32 to 59% of samples and "confirmed" tests showed it to be present in 2 to 14% of all samples only 0 to 7% of samples were carried through to the "complete" stage. It appears as if Campylobacter is more common than may have been previously expected. E. coli O157:H7, on the other hand, is perhaps not as common explaining why the interruption (or inadequacy) of drinking water disinfection systems does not lead to more frequent outbreaks of this pathogen. Includes 6 references, tables, figures.