Health Impact of Treating and Safely Storing Shallow Tubewell Drinking Water

Setting: The investigators will conduct the study in the Fulbaria upazila of Mymensingh district, where groundwater chemistry has been proven to be amenable to disinfection with chlorine. Groundwater in many areas in Bangladesh is rich in iron and other ions that react with chlorine and limit its capacity to provide adequate disinfection. Groundwater testing in Fulbaria has shown that chlorination works effectively at this location, as discussed below.

Develop Intervention: This is an efficacy study, i.e. it is trying to answer the question: if tubewell water were effectively chlorinated and/or safely stored in homes, what would be the impact on childhood diarrhea. To efficiently answer this question, the investigators will strive to optimize the use of the intervention in those households randomized to receive the intervention. Chlorinating water has been shown to be an effective way of disinfecting water in the home (Arnold and Colford, 2007). The investigators will use Aquatabs for chlorination, which are effervescent water purification tablets that utilize sodium dichloroisocyanurate (NaDCC) as the chlorine donor. NaDCC was judged to be a safe and appropriate treatment for water by the World Health Organization (Clasen and Edmondson, 2006) and has been tested and found acceptable to a community of urban residents in Dhaka, Bangladesh (Clasen et al., 2007a). Aquatabs are also easier to store, handle and correctly dose than liquid forms of chlorine (Clasen and Edmondson, 2006).

Groundwater Testing: To optimize the use of Aquatabs and determine the appropriate dose to be assigned to study participants, the investigators collected water samples from 52 shallow tubewells geographically spread out over all 13 unions in Fulbaria. Water was collected in 5L and 10L jerry cans with a narrow mouth and lid. One Aquatabs tablet was added to each vessel, resulting in a free chlorine dose of 2 mg/L in the 10L container and 4 mg/L in the 5L container. Remaining chlorine residual in the vessels was measured half an hour and 24 hours after the addition of the tablet to assess whether it meets the target criteria of having a minimum residual of 0.2 mg/L at 24 hours (to ensure adequate disinfection) and a maximum residual of 2 mg/L at half an hour (to minimize taste and odor concerns). It should be noted that the 2 mg/L taste/odor threshold the investigators are targeting is well under the WHO health limit of 5 mg/L. Based on the testing results, the investigators determined that using one Aquatabs with a 10L jerry can provides the optimal chlorine dose in Fulbaria.

Intervention Groups: The study will have the following three arms, which will allow us to establish the respective roles of household water treatment and safe water storage in preventing diarrheal illness in children in the rural Bangladesh setting.

Group 1 - Aquatabs and Safe Storage Vessel: Households in this group will receive Aquatabs for water purification, a safe water storage container to prevent contamination during storage in the home, and training and encouragement to treat and safely store their water using the provided products.