Microbial contamination of the drinking water distribution system and its impact on human health in Khan Yunis Governorate, Gaza Strip: seven years of monitoring (2000-2006).

OBJECTIVE: To assess total and faecal coliform contamination in water wells and distribution networks over the past 7 years, and their association with human health in Khan Yunis Governorate, Gaza Strip. STUDY
DESIGN: Historical data and interview questionnaire.
METHODS: Data were obtained from the Palestinian Ministry of Health on total and faecal coliform contamination in water wells and distribution networks, and on the incidence of water-related diseases in Khan Yunis Governorate. An interview questionnaire was conducted with 210 residents of Khan Yunis Governorate.
RESULTS: Total and faecal coliform contamination exceeded the World Health Organization's limit for water wells and networks. However, the contamination percentages were higher in networks than in wells. Diarrhoeal diseases were strongly correlated with faecal coliform contamination in water networks (r=0.98). This is consistent with the finding that diarrhoeal diseases were the most common self-reported diseases among the interviewees. Such diseases were more prevalent among subjects who drank municipal water than subjects who drank desalinated or home-filtered water (odds ratio=2.03). Intermittent water supply, insufficient chlorination and sewage flooding seem to be associated with self-reported diseases. Residents in the Gaza Strip have a good level of knowledge about drinking water contamination, and this is reflected in good practice.
CONCLUSIONS: Water quality has deteriorated in the Gaza Strip, and this may contribute to the prevalence of water-related diseases. Self-reported diseases among interviewees in Khan Yunis Governorate were associated with source of drinking water, intermittent water supply, insufficient chlorination, sewage flooding and age of water networks.