title: Impact of population and latrines on fecal contamination of ponds in rural Bangladesh.
abstract: A majority of households in Bangladesh rely on pond water for hygiene. Exposure to pond water fecal contamination could therefore still contribute to diarrheal disease despite the installation of numerous tubewells for drinking. The objectives of this study are to determine the predominant sources (human or livestock) of fecal pollution in ponds and examine the association between local population, latrine density, latrine quality and concentrations of fecal bacteria and pathogens in pond water. Forty-three ponds were analyzed for E. coli using culture-based methods and E. coli, Bacteroidales and adenovirus using quantitative PCR. Population and sanitation spatial data were collected and measured against pond fecal contamination. Humans were the dominant source of fecal contamination in 79% of the ponds according to Bacteroidales measurements. Ponds directly receiving latrine effluent had the highest concentrations of fecal indicator bacteria (up to 10⁶ Most Probable Number (MPN) of culturable E. coli per 100 mL). Concentrations of fecal indicator bacteria correlated with population surveyed within a distance of 30-70 m (p<0.05) and total latrines surveyed within 50-70 m (p<0.05). Unsanitary latrines (visible effluent or open pits) within the pond drainage basin were also significantly correlated to fecal indicator concentrations (p<0.05). Water in the vast majority of the surveyed ponds contained unsafe levels of fecal contamination attributable primarily to unsanitary latrines, and to lesser extent, to sanitary latrines and cattle. Since the majority of fecal pollution is derived from human waste, continued use of pond water could help explain the persistence of diarrheal disease in rural South Asia.
authors.affiliation: Department of Earth and Planetary Sciences, The University of Tennessee, Knoxville, TN 37996-1410, USA. peter.knappett@helmholtz-muenchen.de
authors.forename: Peter S K
authors.initials: PS
authors.lastname: Knappett
authors.forename: Veronica
authors.initials: V
authors.lastname: Escamilla
authors.forename: Alice
authors.initials: A
authors.lastname: Layton
authors.forename: Larry D
authors.initials: LD
authors.lastname: McKay
authors.forename: Michael
authors.initials: M
authors.lastname: Emch
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Williams
authors.forename: R
authors.initials: R
authors.lastname: Huq
authors.forename: J
authors.initials: J
authors.lastname: Alam
authors.forename: Labony
authors.initials: L
authors.lastname: Farhana
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Mailloux
authors.forename: Andy
authors.initials: A
authors.lastname: Ferguson
authors.forename: Gary S
authors.initials: GS
authors.lastname: Sayler
authors.forename: Kazi M
authors.initials: KM
authors.lastname: Ahmed
authors.forename: Alexander
authors.initials: A
authors.lastname: van Geen
mesh_terms: D000256:Adenoviridae / Q000254:growth & development / Q000302:isolation & purification; D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification; D001459:Bangladesh; D004784:Environmental Monitoring; D005243:Feces; D005618:Fresh Water / Q000737:chemistry* / Q000382:microbiology / Q000821:virology; D006801:Humans; D018570:Risk Assessment; D012424:Rural Population; D012722:Sewage / Q000032:analysis* / Q000382:microbiology / Q000821:virology; D014871:Water Microbiology; D014873:Water Pollutants / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
chemical_list: D012722:Sewage; D014873:Water Pollutants