Assessing the Effectiveness of a Point-of-use Water Filter Technology as an Arsenic Mitigation Strategy in West Bengal

The Unilever Pureit As+ filter will be assessed for chemical and microbiological performance and health impact using a parallel, household-randomised controlled trial (RCT) design over a four-month follow-up period.

This study will follow an open (non-blinded) design because filtration technologies are particularly challenging to blinding (Boisson et al., 2010). Equal randomisation will be applied (i.e. 1:1). Randomisation will be undertaken through a lottery organised in each participating village.

The study will be undertaken in two phases; an initial phase will involve a baseline survey in the identified affected communities. Those households identified as eligible during the baseline survey will then be randomised into the intervention or control group and the intervention will then be distributed. After a 2-4 week adaptation period, control and intervention arms will be followed at monthly visits for a period of four months.

The baseline study will collect information on demographics, sanitation facilities, hygiene practices, drinking water sources and treatment practices, diet of household members, knowledge of arsenic contamination and arsenicosis, and other factors that could potentially impact the outcomes of interest. Additionally, data on behavioural factors that have been observed to be associated with Household Water Treatment (HWT) use will be collected to predict intervention use in the intervention arm. During the baseline survey, water samples of source water and stored drinking water will be collected and tested for total thermotolerant coliforms (TTC) and total arsenic concentration. The female head of the household will be invited to provide a sample of urine for total urinary arsenic testing. The female head of the household will be followed because it is expected that she will be the household member that i. is mainly responsible for drinking water management, and ii. is at home most of the day and thus making it logistically feasible to obtain spot urine samples throughout the study.

At monthly intervals, participating households will be visited to assess filter use using self report as well as objective indicators. Additionally, in each round of follow-up, drinking water samples will be taken in all participating households for both microbiological and arsenic testing. Additionally, the female head of household will be invited to provide spot urine samples for total urinary arsenic at each round of follow up.