title: A probabilistic quantitative microbial risk assessment model of norovirus disease burden from wastewater irrigation of vegetables in Shepparton, Australia.
abstract: Wastewater can be an important resource for water-scarce regions of the world, but a major barrier to its use is the associated health risk. Quantitative microbial risk assessment (QMRA) is a probabilistic modeling technique used to determine the health risks from wastewater reuse, but only a handful of QMRA studies have examined the norovirus health risks from consumption of vegetables irrigated with human wastewater, even though norovirus is a, if not the most, significant microbial cause of diarrheal disease world-wide. Furthermore, the majority of these studies have focused only on risks from lettuce consumption. To meet the knowledge gap in health risks for other vegetables, a QMRA model was constructed for agricultural wastewater irrigation in the regional city of Shepparton, Australia, using fecal shedding rates to estimate norovirus concentration in raw sewage. Annual norovirus disease burden was estimated for the consumption of lettuce, broccoli, cabbage, Asian vegetables, and cucumber after irrigation with treated wastewater. Results indicate that the waste stabilization pond treatment did not have sufficient virus removal to meet the World Health Organization (WHO) threshold for acceptable level of risk for wastewater reuse, but addition of disinfection treatments provided acceptable results for consumption of cucumber and broccoli. This is the first QMRA study to incorporate virus accumulation from previous wastewater irrigation events.
authors.affiliation: Department of Agriculture and Food Systems, Melbourne School of Land and Environment, University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: Hoi-Fei
authors.initials: HF
authors.lastname: Mok
authors.affiliation: Department of Resource Management and Geography, Melbourne School of Land and Environment, University of Melbourne, Parkville, VIC 3010, Australia.
authors.forename: S Fiona
authors.initials: SF
authors.lastname: Barker
authors.affiliation: Department of Agriculture and Food Systems, Melbourne School of Land and Environment, University of Melbourne, Parkville, VIC 3010, Australia. Electronic address: andrewjh@unimelb.edu.au.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hamilton
mesh_terms: D057914:Agricultural Irrigation; D001315:Australia; D017250:Caliciviridae Infections / Q000209:etiology*; D017281:Cost of Illness; D006801:Humans; D015233:Models, Statistical; D029322:Norovirus / Q000502:physiology*; D018570:Risk Assessment; D012621:Seasons; D014675:Vegetables / Q000009:adverse effects*; D062065:Wastewater / Q000821:virology*; D018508:Water Purification
chemical_list: D062065:Wastewater
keywords: Agriculture; Diarrhea; Horticulture; Public health; QMRA