Provision of well-water treatment units to 600 households in Bangladesh: A longitudinal analysis of urinary arsenic indicates fading utility

Abstract

Background Millions of villagers in Bangladesh remain exposed to high levels of arsenic (As) from drinking untreated well-water even though the scale of the problem was recognized 15 years ago. Water treatment at the household-level has been promoted as a viable complement but few longitudinal studies of their efficacy using an objective measure of exposure have been conducted. Participants (N=622) of a nutrition trial in Araihazar, Bangladesh were each provided with READ-F filters at the beginning of the study and encouraged to use them over the 6 month duration of the intervention. Well-water As, treated water As, and urinary As were monitored periodically during the trial and measured again one year after the trial ended. Results The READ-F filters were initially well received and median urinary As levels for participants declined from 117 μg/L to 51 μg/L within a single week. However, median urinary As levels gradually rose back to 126 μg/L by the end of the trial. Fifty filters were replaced over the course of the trial because of insufficient As removal or reduced flow. With these exceptions, most of the treated water met the WHO guideline for As in drinking water of 10 μg/L. One year after the nutritional trial ended, 95% of participants had abandoned their filter citing inconvenience as the primary reason. At that time, median urinary As levels for 10 participants who had switched to a nearby low-As well had declined to 63 μg/L. Conclusions Participants were probably no longer using the READ-F filter long before the 6 month nutritional intervention ended despite claiming that they were using them. Household-level treatment is likely to continue to play a minor role in the effort to reduce As exposure in Bangladesh. Understanding the limitations of such expensive interventions is important for future policy regarding As mitigation.

The Influence of Underlying Stresses from Environmental Hazards on Resilience in Bangladesh: A System View

“…Their reliance on maintenance and chemical replacement mean that although they are effective over the short term they cannot be considered a long-term solution. Other issues include inconvenience, disposal of arsenic wastes, and the low willingness-to-pay Shafiquzzaman et al 2009;Feroze Ahmed and Ahmed 2014;Sanchez et al 2016;Bhattacharya et al 2017). In a longitudinal study, Sanchez et al (2016) measured urinary As in 600 Bangladesh households that had adopted READ-F filters and concluded that arsenic exposure could be temporarily reduced from a few weeks to a few months, but household treatment was not considered a sustainable arsenic mitigation option over the long term.…”

“…Improved knowledge of arsenic prevalence and mapping the contamination levels of water sources enables better decision making for communities. Areas with low arsenic concentrations and arsenic-safe wells can be identified, thus promoting community confidence and increasing the popularity of well-switching (Feroze Ahmed and Ahmed 2014; Sanchez et al 2016). Well-switching has to date had by far the largest impact in reducing arsenic exposure from drinking water (Sanchez et al 2016).…”

“…Areas with low arsenic concentrations and arsenic-safe wells can be identified, thus promoting community confidence and increasing the popularity of well-switching (Feroze Ahmed and Ahmed 2014; Sanchez et al 2016). Well-switching has to date had by far the largest impact in reducing arsenic exposure from drinking water (Sanchez et al 2016). Along with knowledge of safe wells, further information exchange between institutions and communities to build hazard awareness is vitally important.…”

“…The drivers of cost and convenience have been identified repeatedly (Johnston et al 2014;Sharma et al 2014). One study found that after just a year, 95% of participants had abandoned household filters primarily because of inconvenience, but also due to other influential factors including willingness-to-pay, ease of maintenance, and psychological barriers (Sanchez et al 2016).…”

“…Inconvenience of additional walking distances and opportunity cost of time commitment are limitations to community-based measures and use of DTWs (Shafiquzzaman et al 2009;Johnston et al 2014;. Similarly, maintenance requirements of arsenic removal technologies and poor flow rates lead to their abandonment (Sanchez et al 2016). Cost is a key limitation and the WTP is generally very low, hence the required capital investments make many solutions cost-prohibitive for household-scale solutions (Johnston et al 2014;Sanchez et al 2016).…”