Human Bacteroides and total coliforms as indicators of recent combined sewer overflows and rain events in urban creeks

Shannon McGinnis, Susan Spencer, Aaron Firnstahl, Joel Stokdyk, Mark Borchardt, David T. McCarthy, Heather M. Murphy

Research output: Contribution to journalArticleResearchpeer-review

10 Citations (Scopus)

Abstract

Combined sewer overflows (CSOs) are a known source of human fecal pollution and human pathogens in urban water bodies, which may present a significant public health threat. To monitor human fecal contamination in water, bacterial fecal indicator organisms (FIOs) are traditionally used. However, because FIOs are not specific to human sources and do not correlate with human pathogens, alternative fecal indicators detected using qPCR are becoming of interest to policymakers. For this reason, this study measured correlations between the number and duration of CSOs and mm of rainfall, concentrations of traditional FIOs and alternative indicators, and the presence of human pathogens in two urban creeks. Samples were collected May–July 2016 and analyzed for concentrations of FIOs (total coliforms and E. coli) using membrane filtration as well as for three alternative fecal indicators (human Bacteroides HF183 marker, human polyomavirus (HPoV), pepper mild mottle virus (PMMoV)) and nine human pathogens using qPCR. Four of the nine pathogens analyzed were detected at these sites including adenovirus, Enterohemorrhagic E. coli, norovirus, and Salmonella. Among all indicators studied, human Bacteroides and total coliforms were significantly correlated with recent CSO and rainfall events, while E. coli, PMMoV, and HPoV did not show consistent significant correlations. Further, human Bacteroides were a more specific indicator, while total coliforms were a more sensitive indicator of CSO and rainfall events. Results may have implications for the use and interpretation of these indicators in future policy or monitoring programs.

Original languageEnglish
Pages (from-to)967-976
Number of pages10
JournalScience of the Total Environment
Volume630
DOIs
Publication statusPublished - 15 Jul 2018

Keywords

  • Combined sewer overflows (CSOs)
  • Enteric pathogens
  • Fecal indicators
  • Human Bacteroides
  • Rainfall
  • Stormwater

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