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

为了减少腹泻病的发病率，在过去的30年里，公共卫生的努力已经导致了几乎普遍的从地表水的消耗转向从浅层含水层（140英尺）的地下水。然而，向浅管井的转变使数千万人暴露于砷之下，从而导致癌症和其他健康问题。地下水砷是美洲和亚洲几个国家的一个主要问题。一种缓解方法是让家庭改用大多深500英尺的公共管井，因为他们从含砷较低的含水层中取水。虽然人们正在安装深管井以减少砷的暴露，但改用这些通常距离较远的井对健康的影响尚未得到充分调查。值得关注的是，从远处的井中获得的水可能在家中储存较长时间，从而增加了长期处理和使用时微生物污染的风险。本研究全面评估了通过砷缓解计划安装的深管井是否为地下水砷问题国家的安全饮用水源。它还提供了关于家庭饮用水储存容器最有可能被水传播病原体污染的情况的见解。最后，这项研究开发了一个关于水、环境卫生和个人卫生的丰富数据库，可供使用，并可与关于同一研究对象的健康、人口和社会经济特征的另一项大型调查联系起来。本研究综合了医学地理学和环境微生物学的疾病生态学传统的理论和方法。它将地理和环境微生物学方法与社区调查相结合，为制定饮用水政策和项目提供至关重要的信息。本研究的目的是：(1)确定深管井是否比浅管井更能预防腹泻疾病；(2)比较深管井和浅管井水源以及家庭储水容器的微生物水质与这些井的水质；(3)确定到深管井的距离和时间越长，储水时间越长，储水容器的水质越差，腹泻疾病的发病率越高。这项研究将在地下水砷最严重的孟加拉国进行。家庭调查将确定水源、使用、储存、卫生和环境卫生习惯。将对管井和家庭储水容器的微生物水质进行测量，以确定大肠杆菌作为粪便指示菌的存在和浓度。到管井的距离将使用地理信息系统数据库测量，该数据库包括住户和管井。分析将确定距离/旅行时间/储存时间是否与储存容器中的水质和腹泻疾病有关。

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.