Arsenic poisoning from groundwater in Bangladesh is a national tragedy, posing a massive threat to public health. About 20 million people are exposed to harmful levels of the chemical element in their drinking water — over 50 parts per billion by national standards — and the figure is several times higher if measured by more stringent World Health Organization standards. Arsenic poisoning is often fatal, linked to increased rates of cancer and other disease. For most of the victims, and millions more yet to be born, there is no end in sight, despite major remedial efforts. With the well-being of so many people at stake, it is time to chart a faster route forward, based on a comprehensive and critical look at ongoing efforts to tackle the problem.
About two decades ago, the government of Bangladesh embarked on a large-scale effort to test shallow household wells for arsenic, a geologically occurring contaminant. The spouts of hand pumps for wells deemed safe were painted green, and those not, red. Households were encouraged to drink only from the green wells. Research showed that up to five years later, as many as half of the households reached were drinking only from safe wells. More recently, the government has shifted to a strategy of introducing piped water from deep public tubewells and other safe sources, making it easier for households to access them. Implementation has proved disappointing, however. At the current annual rate of progress, according to our analysis, it will take more than 100 years to reach all of the most vulnerable people.
Rural households in Bangladesh should not have to wait until the 22nd century for a solution to this devastating and lethal problem. We believe it is possible to quicken the pace of progress now, based on a combination of new technologies and policy measures.
One promising technical solution is to spread the use of household filters, which enable people to rely on their own tubewells and avoid fetching water from distant sources. Costing about $40, filters could be made widely available through subsidies. A related approach employs filters to treat large volumes of water from community wells. Users typically pay a small monthly fee to cover the costs of maintenance and operations. A newer technique for removing arsenic from groundwater, called “in situ oxidation,” involves modifying the water, through the use of iron oxides and micro-organisms, before it is withdrawn from wells. Based on pilot testing in Bangladesh, the equipment and maintenance seem straightforward, but the cost-effectiveness and sustainability of this technique remain to be proven.
Beyond pipe dreams: Getting the interventions right
There is now a growing consensus around the need to take action in this crisis and make solutions more readily accessible. This will require several new policy measures that reflect a clear grasp of the arsenic crisis in Bangladesh.
1. Test and retest wells
In the years since previous rounds of testing ended, the green or red paint on many wells has washed away. This, together with other changes such as the installation of new untested wells and the contamination of safe wells, have eroded the gains from earlier efforts. There is a clear need to renew testing and retesting through concerted campaigns that make reliable and affordable testing materials widely available for regular use. Test results must also be made readily accessible to the public, so they can inform local action. Renewed testing will also provide a foundation for effective targeting of new remedial measures, since the severity of the problem varies greatly, even within a single village, depending on geological and other conditions.
2. Widen the net
The spread of shallow tubewells from the 1980s onwards came in response to high levels of harmful pathogens and other contaminants in surface water. As households cease to rely for drinking water on tubewells contaminated with arsenic, microbial contamination of alternative water sources will require increased attention. Researchers have identified other contaminants as well in the water supplies of rural households, including manganese, lead, nickel, and chromium. Fortunately, many of the measures that reduce arsenic are also effective against these other elements. Redoubled efforts to tackle arsenic thus represent an important opportunity to address multiple health threats through a more holistic approach to water contaminants.
3. Set sensible and fair priorities
Given the magnitude of the arsenic problem and resource limitations at every level, rolling out new technologies is highly complex. To be both fair and realistic, programs must be guided by clear priorities as to where they will act, what they will do first, and which people will receive urgent attention. Even though much is known about where the arsenic problem is most severe, many studies cite cases in which remedial measures have been applied where the threat is low. Clearly, more must be done to improve targeting. New initiatives must also aim for equity, using tools such as social cost-effectiveness analysis to allocate scarce resources from both public and private sources. By taking into account costs such as women’s time and effort in carrying water, such analysis can help target resources to the most disadvantaged members of society.
4. Grease the supply chain
Some of the new measures to reduce arsenic contamination have been tested on a pilot basis as part of research projects. The next step is to build supply chains for scaling up these solutions sustainably, based on an understanding of community preferences, their willingness to pay, and the size of the financial gap that must be covered from other sources. New projects must also confront regulatory and other obstacles that threaten to slow progress.
Bangladesh can bring an end to groundwater arsenic contamination only through a massive response from the public and private sectors with civil society — one guided by science and a thorough knowledge of the local realities behind this national crisis.