title: Distribution and persistence of Escherichia coli and Enterococci in stream bed and bank sediments from two urban streams in Houston, TX.
abstract: The purpose of this research was to determine if Escherichia coli and enterococci in streambed and bank sediments from two urban bayous, Buffalo Bayou and White Oak Bayou, in Houston, TX, USA are a significant source of the chronically high levels of these bacteria in the overlying water. The watersheds of the bayous lie within highly urbanized areas of Greater Houston and there is primary recreational contact with the public. Extensive sampling of the watersheds was conducted from 2008 to 2010. Both fecal indicator bacteria were found at ≥ 10(4)MPNgdry wt.(-1) concentrations in the upper 1cm of sediment cores with declines by orders of magnitude at 15 and 30 cm sediment horizons and in some cases 60 cm, but, nonetheless, indicating that they can remain viable even at depth. No interannual variation was observed. And, there was no correlation with percent organic matter, however there was moderate correlation (R(2)=0.12; p=0.001) of E. coli with sediment moisture. In sediments, most E. coli and enterococci in Buffalo Bayou (76%) and White Oak Bayou (87.5%) were associated with fine sand grains (60 to 250 μm). In the water column, E. coli was associated, in roughly equal percentages, with particle sizes <10, 10-25, 25-63, and ≥ 63 μm (21.9, 25.6, 30.4, and 32.9%, respectively). Enterococci were mostly attached to particle sizes in the ranges of 10-25μm (36.0%) and 25-63 μm (31.1%) as well as ≥ 63 μm (37.7%) (p=0.0001). Fingerprinting of E. coli isolates from both bayous with Rep-PCR and the BOX A1R primer was used to demonstrate translocation of sediments from the upper to lower watersheds.
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA. Electronic address: brinkmer@tamug.edu.
authors.forename: Robin
authors.initials: R
authors.lastname: Brinkmeyer
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA.
authors.forename: Rainer M W
authors.initials: RM
authors.lastname: Amon
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77553, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Schwarz
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA. Electronic address: tsaxton@glorienergy.com.
authors.forename: Tara
authors.initials: T
authors.lastname: Saxton
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA. Electronic address: dustin.roberts@tecq.texas.gov.
authors.forename: Dustin
authors.initials: D
authors.lastname: Roberts
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA. Electronic address: sah288@msstate.edu.
authors.forename: Sarah
authors.initials: S
authors.lastname: Harrison
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA. Electronic address: nicholas.ellis@tceq.texas.gov.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Ellis
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA. Electronic address: jessica.fox@tceq.texas.gov.
authors.forename: Jessica
authors.initials: J
authors.lastname: Fox
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: DiGuardi
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, Galveston, TX 77553, USA.
authors.forename: Mona
authors.initials: M
authors.lastname: Hochman
authors.affiliation: Department of Marine Sciences, Texas A&M University at Galveston, Galveston, TX 77553, USA. Electronic address: sduan@umd.edu.
authors.forename: Shuiwang
authors.initials: S
authors.lastname: Duan
authors.affiliation: Total Maximum Daily Loads Program, Texas Commission on Environmental Quality, Austin, TX 78753, USA.
authors.forename: Ron
authors.initials: R
authors.lastname: Stein
authors.affiliation: Harris County Flood Control District, Houston, TX 77092, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Elliott
mesh_terms: D016983:Enterococcus / Q000145:classification / Q000254:growth & development*; D004784:Environmental Monitoring; D004926:Escherichia coli / Q000145:classification / Q000254:growth & development*; D019015:Geologic Sediments / Q000382:microbiology*; D045483:Rivers / Q000382:microbiology*; D013781:Texas; D014507:Urbanization; D014871:Water Microbiology; D014872:Water Movements
keywords: Enterococci; Escherichia coli; Sediment; Urban stream; Watershed