title: Managing Microbial Risks from Indirect Wastewater Reuse for Irrigation in Urbanizing Watersheds.
abstract: Limited supply of clean water in urbanizing watersheds creates challenges for safely sustaining irrigated agriculture and global food security. On-farm interventions, such as riverbank filtration (RBF), are used in developing countries to treat irrigation water from rivers with extensive fecal contamination. Using a Bayesian approach incorporating ethnographic data and pathogen measurements, quantitative microbial risk assessment (QMRA) methods were employed to assess the impact of RBF on consumer health burdens for Giardia, Cryptosporidium, rotavirus, norovirus, and adenovirus infections resulting from indirect wastewater reuse, with lettuce irrigation in Bolivia as a model system. Concentrations of the microbial source tracking markers pepper mild mottle virus and HF183 Bacteroides were respectively 2.9 and 5.5 log10 units lower in RBF-treated water than in the river water. Consumption of lettuce irrigated with river water caused an estimated median health burden that represents 37% of Bolivia's overall diarrheal disease burden, but RBF resulted in an estimated health burden that is only 1.1% of this overall diarrheal disease burden. Variability and uncertainty associated with environmental and cultural factors affecting exposure correlated more with QMRA-predicted health outcomes than factors related to disease vulnerability. Policies governing simple on-farm interventions like RBF can be intermediary solutions for communities in urbanizing watersheds that currently lack wastewater treatment.
authors.affiliation: Department of Civil & Environmental Engineering, University of South Florida , 4202 E. Fowler Avenue, Tampa, Florida 33620, United States.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Verbyla
authors.affiliation: College of Marine Science, University of South Florida , 140 Seventh Avenue South, St. Petersburg, Florida 33701, United States.
authors.forename: Erin M
authors.initials: EM
authors.lastname: Symonds
authors.affiliation: Department of Mathematics & Statistics, University of South Florida , 4202 E. Fowler Avenue, Tampa, Florida 33620, United States.
authors.forename: Ram C
authors.initials: RC
authors.lastname: Kafle
authors.affiliation: Department of Anthropology, University of South Florida , 4202 E. Fowler Avenue, Tampa, Florida 33620, United States.
authors.forename: Maryann R
authors.initials: MR
authors.lastname: Cairns
authors.affiliation: Center for Water and Environmental Sanitation (Centro de Aguas y Saneamiento Ambiental, CASA), Universidad Mayor de San Simon , Cochabamba, Bolivia.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Iriarte
authors.affiliation: Center for Water and Environmental Sanitation (Centro de Aguas y Saneamiento Ambiental, CASA), Universidad Mayor de San Simon , Cochabamba, Bolivia.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Mercado Guzmán
authors.affiliation: Center for Water and Environmental Sanitation (Centro de Aguas y Saneamiento Ambiental, CASA), Universidad Mayor de San Simon , Cochabamba, Bolivia.
authors.forename: Olver
authors.initials: O
authors.lastname: Coronado
authors.affiliation: College of Marine Science, University of South Florida , 140 Seventh Avenue South, St. Petersburg, Florida 33701, United States.
authors.forename: Mya
authors.initials: M
authors.lastname: Breitbart
authors.affiliation: Center for Urban Planning and Management (Centro de Planificación y Gestión, CePlaG), Universidad Mayor de San Simon , Cochabamba, Bolivia.
authors.forename: Carmen
authors.initials: C
authors.lastname: Ledo
authors.affiliation: Department of Civil & Environmental Engineering, University of South Florida , 4202 E. Fowler Avenue, Tampa, Florida 33620, United States.
authors.forename: James R
authors.initials: JR
authors.lastname: Mihelcic
mesh_terms: D057914:Agricultural Irrigation; D001499:Bayes Theorem; D005872:Giardia; D006801:Humans; D029322:Norovirus; D018570:Risk Assessment; D062065:Wastewater / Q000821:virology*
chemical_list: D062065:Wastewater