Groundwater and stream E. coli concentrations in coastal plain watersheds served by onsite wastewater and a municipal sewer treatment system.


Journal Article

The goal of this study was to determine if onsite wastewater treatment systems (OWS) were influencing groundwater and surface water Escherichia coli concentrations in a coastal plain watershed. Piezometers for groundwater monitoring were installed at four residences served by OWS and five residences served by a municipal wastewater treatment system (MWS). The residences were located in two different, but nearby (<3 km), watersheds. Effluent from the four septic tanks, groundwater from piezometers, and the streams draining the OWS and MWS watersheds were sampled on five dates between September 2011 and May 2012. Groundwater E. coli concentrations and specific conductivity were elevated within the flow path of the OWS and near the stream, relative to other groundwater sampling locations in the two watersheds. Groundwater discharge in the OWS watershed could be a contributor of E. coli to the stream because E. coli concentrations in groundwater at the stream bank and in the stream were similar. Stream E. coli concentrations were higher for the OWS in relation to MWS watersheds on each sampling date. Water quality could be improved by ensuring OWS are installed and operated to maintain adequate separation distances to water resources.

Full Text

Duke Authors

Cited Authors

  • Humphrey, C; Finley, A; O'Driscoll, M; Manda, A; Iverson, G

Published Date

  • January 2015

Published In

Volume / Issue

  • 72 / 10

Start / End Page

  • 1851 - 1860

PubMed ID

  • 26540548

Pubmed Central ID

  • 26540548

Electronic International Standard Serial Number (EISSN)

  • 1996-9732

International Standard Serial Number (ISSN)

  • 0273-1223

Digital Object Identifier (DOI)

  • 10.2166/wst.2015.411


  • eng