title: Spatial Variability ofEscherichia coliin Rivers of Northern Coastal Ecuador.
abstract: The use of contaminated surface water continues to be a pressing issue in areas of the world where people lack improved drinking water sources. In northern coastal Ecuador, many communities rely on untreated surface water as their primary source of drinking water. We undertook a study to explore how microscale river hydrodynamics affect microbial water quality at community water collection locations at three rivers with varying stream velocity and turbidity profiles. To examine how the distance from river shore and physiochemical water quality variables affect microbial contamination levels in the rivers; we collected a total of 355 water samples within six villages on three rivers; and tested forEscherichia coliconcentrations using the IDEXX Quanti-tray method. We found that log10E. coliconcentrations decreased with increasing distance from shore (β = -0.017;p= 0.003). Water in the main channel hadE. coliconcentrations on average 0.12 log10lower than within eddies along the river shore and 0.27 log10lower between the sample closest to shore and any sample >6 m from the shore. HigherE. coliconcentrations were also significantly associated with increased turbidity (β = 0.003;p< 0.0001) and decreased dissolved oxygen levels (β = -0.310;p< 0.0001). The results of this study can help inform community members about the safest locations to collect drinking water and also provide information on watershed scale transport of microbial contaminants between villages.
authors.affiliation: Department of Environmental Health, Emory University, 1518 Clifton Rd, Atlanta, GA 30322, USA.
authors.forename: Gouthami
authors.initials: G
authors.lastname: Rao
authors.affiliation: Department of Epidemiology, University of Michigan, M5065 SPH II, 1415 Washington Heights, Ann Arbor, MI 48109-2029, USA.
authors.forename: Joseph N S
authors.initials: JN
authors.lastname: Eisenberg
authors.affiliation: Department of Epidemiology, Emory University, 1518 Clifton Rd, Atlanta, GA 30322, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Kleinbaum
authors.affiliation: Centro de Biomedicina, Universidad Central del Ecuador, Carrera de Medicina Sodiro N14-121 e Iquique, Quito, Ecuador.
authors.forename: William
authors.initials: W
authors.lastname: Cevallos
authors.affiliation: Universidad San Francisco de Quito, Diego de Robles y Vía Interoceánica, Quito 170157, Ecuador.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Trueba
authors.affiliation: Department of Environmental Health, Emory University, 1518 Clifton Rd, Atlanta, GA 30322, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Levy
keywords: Ecuador; Escherichia coli; hydrodynamics; water quality