Epidemiological study for the assessment of health risks associated with graywater reuse for irrigation in arid regions

Allison Busgang, Eran Friedler, Ofer Ovadia, Amit Gross

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Graywater reuse is rapidly gaining popularity as a viable source of reclaimed water, mainly for garden irrigation and toilet flushing. The purpose of this study was to determine, by epidemiological survey, the risk for gastroenteritis symptoms associated with graywater reuse. The study comprised a weekly health questionnaire answered by both graywater users and non-graywater users (control group) regarding their health status over a period of 1year, and periodic sampling for graywater quality. Participants were also asked to respond to a one-time lifestyle questionnaire to assess their level of exposure to graywater or potable water used in garden irrigation. Graywater quality was typical and comparable to previous studies, with average fecal coliform concentration of 103CFU 100ml-1. A Cox Proportional Hazards model indicated a somewhat higher health risk for the control group (P<0.05), suggesting that there was practically no difference in the prevalence of water-related diseases between users of graywater and potable water. Since the concentration of pathogens in the current study was higher than that suggested by quantitative microbial risk assessment (QMRA), yet there was no difference in the prevalence of water-related diseases between control and graywater users, it was postulated that QMRA is conservative and can safely be used toward the establishment of regulations governing graywater reuse.

Original languageEnglish
Pages (from-to)230-239
Number of pages10
JournalScience of the Total Environment
StatePublished - 5 Dec 2015


  • Epidemiology
  • Gastroenteritis
  • Graywater
  • Risk analysis

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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