title: Microbial source tracking to identify human and ruminant sources of faecal pollution in an ephemeral Florida river.
abstract: OBJECTIVE
  Levels and sources of faecal indicator bacteria (FIB) in an ephemeral Florida river were assessed under different rainfall/flow patterns to explore the effects of rainfall on water quality.
  
  
  RESULTS
  Quantitative PCR for sewage markers [human-associated Bacteroides HF183 and human polyomaviruses (HPyVs)] and PCR for ruminant faecal markers were used to explore contamination sources. Escherichia coli, faecal coliform and enterococci levels consistently exceeded recreational water quality criteria, and sediment FIB levels were about 100-fold higher compared with water. HPyVs detections cooccurred with HF183, which was frequently detected near septic systems. Ruminant markers were detected only in livestock-grazing areas. Significantly greater faecal coliform and E. coli concentrations were observed under no-flow conditions and the levels of faecal coliforms in water column and sediments were negatively correlated with duration since last rain event.
  
  
  CONCLUSIONS
  Septic systems and cattle grazing in this watershed contributed to the formation of FIB reservoirs in sediments, which were persistent following prolonged rainfall.
  
  
  CONCLUSIONS
  Ephemeral water bodies that flow only under the direct influence of recent rainfall are rarely studied. FIB levels in the New River in Florida were greater during dry weather than wet weather, which contrasts with most observations and may be attributed to bacterial reservoirs formed in still pool, sediments and water-saturated soils in this subtropical environment.
authors.affiliation: Department of Integrative Biology, University of South Florida, Tampa, FL 33620, USA.
authors.forename: E
authors.initials: E
authors.lastname: Chase
authors.forename: J
authors.initials: J
authors.lastname: Hunting
authors.forename: C
authors.initials: C
authors.lastname: Staley
authors.forename: V J
authors.initials: VJ
authors.lastname: Harwood
mesh_terms: D000818:Animals; D002417:Cattle; D015169:Colony Count, Microbial; D004755:Enterobacteriaceae / Q000302:isolation & purification; D004784:Environmental Monitoring / Q000379:methods*; D004787:Environmental Pollution / Q000032:analysis*; D004926:Escherichia coli / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology*; D005431:Florida; D005819:Genetic Markers; D006801:Humans; D016133:Polymerase Chain Reaction; D011891:Rain; D045483:Rivers / Q000382:microbiology*; D012722:Sewage / Q000382:microbiology; D014871:Water Microbiology; D014872:Water Movements; D060753:Water Quality
chemical_list: D005819:Genetic Markers; D012722:Sewage