Chlorination not necessary to make tubewell water safe for drinking

Although chlorine is widely used to make water clean and safe, an ICDDR,B study suggests that storing and handling water correctly is sufficient for reducing contamination of tubewell water and diarrhoea in children without using chlorine.

A new randomised controlled trial led by ICDDR,B investigators has shown that drinking water drawn from tube-wells is contaminated with faecal pathogens during handling and storing of water at the household, demonstrating that this contamination, which causes waterborne illnesses like diarrhoea, is largely preventable through the consistent practice of safe storage methods.

Water chlorination is the process of adding chlorine or hypochlorite to water. This method is used to kill certain bacteria and other microbes in tap water as chlorine is highly toxic. In particular, chlorination is used to prevent the spread of waterborne diseases like diarrhoea, dysentery and typhoid.

The trial included 1,800 households in a rural area of Bangladesh and these were randomly assigned to one of three groups -- a control group that received no intervention, a safe storage group and a group that was provided with both safe storage and chlorine tablets for treatment of their drinking water.

The groups were then monitored and compared for one year to measure the impact of the different interventions.

Both intervention groups showed a significant reduction in diarrhoea among children under the age of two as reported by caregivers, and an improvement in tested water quality compared to the control group in which households received nothing. But interestingly, the scientists found that there was no real benefit to the addition of chlorine treatment.

Dr Leanne Unicomb, a co-author of the study, said these findings are significant because they imply that rural Bangladeshi households using tubewell water for drinking may only need to purchase and maintain a durable low cost household safe water storage vessel and make a modest behaviour change in order to see a large improvement in safe drinking water.