Zuckerberg Institute for Water Research, Blaustein Institutes for Desert Research, Ben Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben Gurion 84990, Israel.
Faculty of Civil & Environmental Engineering, Technion - Israel Institute of Technology, Haifa 3200003, Israel.
Sci Total Environ. 2015 Dec 15;538:230-9. doi: 10.1016/j.scitotenv.2015.08.009. Epub 2015 Aug 24.
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 10(3)CFU 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.
灰水再利用作为一种可行的再生水来源，正在迅速普及，主要用于花园灌溉和冲洗厕所。本研究旨在通过流行病学调查，确定与灰水再利用相关的肠胃炎症状风险。研究包括每周一次的健康问卷，由灰水使用者和非灰水使用者（对照组）回答，内容为他们在一年期间的健康状况，以及定期对灰水质量进行抽样。参与者还被要求回答一次性生活方式问卷，以评估他们接触灰水或用于花园灌溉的饮用水的程度。灰水质量是典型的，与以前的研究相当，平均粪大肠菌群浓度为 10(3)CFU 100ml(-1)。Cox 比例风险模型表明对照组的健康风险略高（P<0.05），这表明灰水和饮用水使用者之间的水相关疾病的患病率实际上没有差异。由于本研究中病原体的浓度高于定量微生物风险评估（QMRA）所建议的浓度，但对照组和灰水使用者之间的水相关疾病的患病率没有差异，因此推测 QMRA 是保守的，可以安全地用于制定管理灰水再利用的规定。
