Finding Safe Drinking Water to Mitigate Arsenic Contamination: Tube Wells, Storage, and Diarrhea

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In an effort to reduce diarrheal disease incidence, public health efforts during the past 30 years have led to an almost universal shift from the consumption of surface water to groundwater from shallow aquifers (140 feet). The shift to shallow tube wells, however, has exposed tens of millions of people to arsenic, which causes cancer and other health problems. Groundwater arsenic is a major problem in several countries in the Americas and Asia. One mitigation approach has been for households to switch to deep public tube wells that are mostly 500 feet deep because they tap water in an aquifer that is low in arsenic. Although deep tube wells are being installed to reduce exposure to arsenic, the health effects of switching to these often more distant, wells has not been adequately investigated. A concern is that water obtained from a distant well may be stored for a longer period of time in the home, thereby increasing the risk of microbial contamination by extended handling and use. This study provides a comprehensive assessment of whether deep tube wells installed through arsenic mitigation programs are a safe drinking water source in countries groundwater arsenic problem. It also provides insights about the circumstances in which household drinking water storage containers are most likely to be contaminated with waterborne pathogens. Lastly, the study develops a rich database on water, sanitation, hygiene that will be made available and can be linked to another large survey on the health, demographic, and socioeconomic characteristics of the same study population. This study integrates theory and methods from the disease ecology tradition of medical geography and environmental microbiology. It combines geographic and environmental microbiology methods with community surveys to provide information that is critical for developing drinking water policies and programs. The objectives of this study are to: (1) determine if deep tube wells protect against diarrheal diseases compared to shallow tube wells, (2) compare the microbial water quality of deep and shallow tube well sources and from household storage containers with water from those wells, and (3) determine if longer travel distance and time to deep tube wells leads to longer duration of water storage, poor water quality in storage containers, and higher diarrheal disease incidence. The study will be conducted in Bangladesh where groundwater arsenic is most severe. A household survey will determine water source, use, storage, hygiene, and sanitation practices. The microbial water quality of tube wells and household water storage containers will be measured for the presence and concentrations of E. coli as fecal indicator bacteria. Distance to tube wells will be measured using a geographic information system database that includes households and tube wells. The analysis will determine if distance/travel time/storage time is related to water quality in storage containers and diarrheal diseases.