title: Quantitative multi-year elucidation of fecal sources of waterborne pathogen contamination in the South Nation River basin using bacteroidales microbial source tracking markers.
abstract: Over a seven-year period (2004-2010) 1095 water samples were obtained from the South Nation River basin at multiple watershed monitoring sites (Ontario, Canada). Real-time PCR using Bacteroidales specific markers was used to identify the origin (human (10% prevalence), ruminant (22%), pig (~2%), Canada goose (4%) and muskrat (7%)) of fecal pollution. In parallel, the distribution of fecal indicator bacteria and waterborne pathogens (Cryptosporidium oocysts, Giardia cysts, Escherichia coli O157:H7, Salmonella enterica and Campylobacter spp.) was evaluated. Associations between the detection of specific Bacteroidales markers and the presence of fecal indicator bacteria, pathogens, and distinct land use or environmental variables were evaluated. Linear correlations between Bacteroidales markers and fecal indicator bacteria were weak. However, mean marker densities, and the presence and absence of markers could be discriminated on the basis of threshold fecal indicator densities. The ruminant-specific Bacteroidales marker was the most frequently detected marker in water, consistent with the large number of dairy farms in the study area. Detection of the human or the ruminant markers were associated with a slightly higher risk of detecting S. enterica. Detection of the muskrat marker was related to more frequent Campylobacter spp. detections. Important positive associations between markers and pathogens were found among: i) total Bacteroidales and Cryptosporidium and Giardia, ii) ruminant marker and S. enterica, and iii) muskrat and Campylobacter spp.
authors.affiliation: Agriculture and Agri-Food Canada, 1391 Sandford Str., London, Ontario N5V 4T3, Canada.
authors.forename: Romain
authors.initials: R
authors.lastname: Marti
authors.forename: Victor P J
authors.initials: VP
authors.lastname: Gannon
authors.forename: Cassandra
authors.initials: C
authors.lastname: Jokinen
authors.forename: Martin
authors.initials: M
authors.lastname: Lanthier
authors.forename: David R
authors.initials: DR
authors.lastname: Lapen
authors.forename: Norman F
authors.initials: NF
authors.lastname: Neumann
authors.forename: Norma J
authors.initials: NJ
authors.lastname: Ruecker
authors.forename: Andrew
authors.initials: A
authors.lastname: Scott
authors.forename: Graham
authors.initials: G
authors.lastname: Wilkes
authors.forename: Yun
authors.initials: Y
authors.lastname: Zhang
authors.forename: Edward
authors.initials: E
authors.lastname: Topp
mesh_terms: D000818:Animals; D041963:Bacteroidetes / Q000302:isolation & purification*; D016001:Confidence Intervals; D004784:Environmental Monitoring; D005243:Feces / Q000382:microbiology*; D006801:Humans; D016017:Odds Ratio; D009864:Ontario; D045483:Rivers / Q000382:microbiology*; D012621:Seasons; D014871:Water Microbiology; D014876:Water Pollution / Q000032:analysis*