Patricia Kubala

Science and Society Module Development Project

Advisors: Martin Stute, Art Lerner-Lam

May 2000

PPT slides of class presentation


Concentrations of arsenic at levels dangerous to human health first began to be detected in Bangladesh's groundwater drinking supplies in 1993. Since that time, as more and more information has accumulated, the scope of the problem is still not thoroughly known but recognized to be enormous, with at least 20 million out of Bangladesh's 125 million people thought to be affected, earning the problem the largest mass poisoning in history (World Bank 1999). The solution is elusively simple: provide clean drinking water to those now drinking from contaminated wells. The history of the problem, sadly, arises out of attempts to do just that -- Much of Bangladesh's surface water is unsafe for human consumption because it contains high concentrations of fecal bacteria or agricultural fertilizer run-off (UNICEF 2000). In the early seventies, the majority of people obtained their water from surface water sources such as ponds; one tubewell existed for every 400 people. The government of Bangladesh and international aid organizations such as UNICEF began installing deep and shallow tube wells throughout the country in hopes of decreasing the incidence of diarrhea diseases and the rate of infant mortality, which it accomplished (World Bank 1999). The tubewells, of which there are now at least four million, were not tested for levels of arsenic or other heavy metals (Leprowski 1999). Further complicating matters, wells in close proximity to each other contain different concentration levels, with some meeting the government of Bangladesh's standard of 0.05 mg/1, and others vastly exceeding that (UNICEF 2000).

In many ways this public health crisis can be viewed as a crisis of lack of information. The following statement by World Bank advisor Guy Alaerts, commenting on that agency's involvement in mitigation efforts beginning in 1997, points to the many obstacles to knowledgably addressing the situation,

When we started designing the project, the degree of urgency was inversely proportional to the amount of information on hand. We had very limited insight into the extent, cause, and impact of the contamination and poisoning; there were no simple technological answers available for this type of problem, nor did the country have much experience with low-cost water supply beyond shallow hand pumps. We would have to conduct millions of measurements of arsenic in the filed, yet worldwide only the first steps were being taken to develop a cheap and reliable field test kit. And most difficult of all, as the nature of the contamination forced us to work locally with the rural communities, there was no proven methodology in Bangladesh to develop sustainable service delivery at the grass-root level. Furthermore, each of the 60,000 villages suspected of being at risk was likely to require a tailor-made solution. So, we had to conceive this effort as one progressive, phased, learning-by-doing program (World Bank 1999). In addition to these gaps in knowledge on the part of scientific and medical researchers and development agency professionals, Bangladeshi villagers were and many still remain unaware or unconvinced of the problem and its source. Skin lesions that appear due to arsenicosis are sometimes confused with leprosy, and individuals or villages with large visibly affected populations are often shunned as lepers (World Bank 1999).


The situation calls for attention on both a short-term, emergency basis as well as a long-term one. On both time-scales, relevant research knowledge needs to be generated by geochemists, hydrogeologists, toxicologists, epidemiologists; improved testing kits and mitigation technologies are also urgently needed. This information then must be effectively collected, synthesized, and disseminated to NGOs, development organizations, officials from government agencies, and communities in order to successfully facilitate, design, and implement informed solutions. On-going collaborative mitigation projects between these stakeholders will be discussed latter in the report.

Geochemical and Hydrogeological Issues

Numerous hydrogeological and geochemical questions have yet to be answered in terms of understanding the specific processes through which arsenic levels have become concentrated in well water. Scientists agree that the origin of the arsenic is in alluvial sediments deposited by the Ganges, Branmaputra, and Meghna rivers. At issue are the processes by which these sediments were laid down, their distribution and makeup, and the reactions by which arsenic (As) is mobilized into groundwater (Acharyya et al. 1999). Questions as to the movement of As within the aquifers as well as the specific factors determining spatial and temporal variability are also unresolved. When the problem was first identified, the theory was put forth that the arsenic was mobilized through pyrite oxidation, such that due to pumping, air or water with dissolved oxygen mixed with the groundwater, resulting in the oxidation of arsenic-rich pyrite in the aquifer sediments. Ross Nickson and his colleagues, in their 1998 article published in Nature, proposed a second theory that the reduction of arsenic-rich iron oxyhydroxides in anoxic groundwater results in the release of arsenic (Nickson et al. 1998). The debate continues and is politically charged, for if the first theory proves correct in instances, than it implicates the high use of groundwater for improved agricultural productivity as a reason behind the problem (Acharyya et al 1999). Researchers seem to have correlated depth of wells with presence of high arsenic levels, as aquifers deeper than 150-200 meters generally seem to be free of dangerous concentrations, yet their feasibility needs to be assessed on a site-specific basis because of variations in water salinity, drilling difficulties, and the possibility of contamination by more shallow layers of sediment (British Geological Survey 1999). Further research will hopefully enable more informed placement of wells, as knowledge of sediment composition and arsenic mobilization mechanisms improves.

Health Issues

Health effects from chronically consuming water with high levels of arsenic take five or more years to appear. However, high concentration levels in a well may not necessarily correlate with high levels of arsenic symptoms among the well's drinkers. This makes detection difficult and complicates attempts to calculate intake levels and correlate those with resulting health problems (WHO 1999). The training of health officials to recognize symptoms of arsenic poisoning, as well as promoting information campaigns to explain the dangers of drinking unsafe water to villagers is a priority, but this task is complicated both by the above-given uncertainties as well as by the phenomenon that among people using water from the same well, some may appear visibly sick while others seem healthy. The factors involved with this are still poorly understood but there is some studies suggest that variations in diet, overall health, and immunity are part of the cause (UNICEF 2000).

Many long-term medical research issues thus present themselves, which will become increasingly crucial as time passes and the slow onset of symptoms and illnesses becomes more apparent. Outstanding problems include understanding what factors increase susceptibility to the disorders known to be induced by arsenic poisoning -- hyperpigmentation, keratosis, peripheral vascular disorders, and skin cancer. The relationship between specific health outcomes and amount of exposure, the degree to which As cycles through food chains and impacts health in this way, and the linkage of arsenic intake to other disorders such as diabetes and hypertension are all issues that need further research (WHO 1999). The affect of mother's intake upon unborn children is also a subject of research (personal communication with Joseph Graziano, May 2000).

Technology Issues

Of urgent need from the research and development sector is the development of sensitive, reliable, low-cost equipment for testing As in the field, and affordable technologies for small-scale arsenic removal for household or village wells. Bangladesh has at least four million tube wells, all of which (ideally) need to be tested and monitored because of the variability of arsenic concentrations in wells at close proximity. The most sophisticated method of measuring arsenic concentrations, that of using an atomic adsorption spectrophotometer (AAS) is out of the question in terms of both expense and coordination of sampling (WHO 1999). Available field testing kits are not sensitive enough to detect mid-range concentration levels (.02-.05 mg/l) that are detrimental to human health. The Bangladesh Chemical and Biological Society of North America is a group that has criticized the testing methods that UNICEF, the World Bank, and NGOs have been using as insensitive (Leprowski 1999). UNICEF itself acknowledges that a better commercial field-testing kit is needed (UNICEF 2000).

Because the most effective known treatment for arsenic poisoning is the drinking of clean water, the development and implementation of mitigation technologies, or the identification of and use of alternative safe water sources, is of great importance. As mentioned earlier in the report, in many areas, surface water is contaminated and therefore not an alternative without treatment or boiling, which requires use of large amounts of fuel not readily available. Options other than use of groundwater are being explored, including rainwater harvesting systems and pond sand filtering which removes bacteria from surface water through slow filtering through a large tank filled with sand and gravel (UNICEF 2000). Although proven methods for filtering arsenic from water exist, most of them are designed for large municipal scales. The development of methods suitable for small scale, low-cost removal are currently underway, and being tested on site. A technique that has received some media attention is an iron and sand pump designed by Nikolas Nikolaidis of the University of Connecticut, in which water is passed through a tube over a well tap that contains sand and iron filings. The iron oxidizes in the presence of barium sulphate and reacts with arsenic to form arsenopyrite, an insoluble compound that precipitates out and is trapped in the filter. This is now being tested with hopes that it eventually will be put on the market (Beard 1998).  A further issue with filtering devices is the need for strategies to safely dispose of resulting toxic precipitants (UNICEF 2000).

Sociological and Institutional Complications

As mentioned earlier in the report, lack of knowledge on the part of villagers as to the presence of arsenic in well water or its health affects has sometimes resulted in the stigmatization and ostracization of some community members with visible symptoms. Women have been rejected by husbands or unable to marry; children are kept out of school as parents attempt to hide their symptoms (World Bank 1999).

Sometimes villagers are reluctant to stop using tubewell water once they have been told it is contaminated, because the wells are associated with kinship networks or are status symbols of wealth and prosperity. The delay in manifestation of symptoms and the variations in health affects on different drinkers of the same well also lessens the villagers' sense of need to move away from the consumption of contaminated water (Bearak 1998).

The government of Bangladesh and international development organizations such as the World Bank have been under heated criticism for their slow efforts to acknowledge the problem and assist its victims (Leprowski 1999). UNICEF is being sued by a Bangladeshi group called the Forum for Arsenic Patients for its role in neglecting to test tubewells for high metal concentrations (Mahmud and Capella 1999). Bangladeshi scientists accuse the government of ignoring their scientific expertise and letting the problem become one addressed by bureaucrats and foreign expertise. Some feel the behavior of visiting researchers has been inappropriate, with scientists not properly explaining their work or intentions and villagers expecting the researchers to return with a cure that, of course, never comes (Leprowski 1999).

Because the government of Bangladesh does not have the resources to provide the affected population with people with emergency safe water supplies, and because of the spatial variability of contaminated well sites, site-specific solutions must be found and implemented with mitigation technologies and strategies appropriate to the resources of the community. This necessitates active community participation and transfer of knowledge from researchers and government officials to NGOs and community leaders. Because significant awareness of the problem and attempts to address it are in beginning stages, very little social science research has yet been published examining what forms of information dissemination have been most effective and what interactions between government officials, development agency representatives, NGO workers, scientists, and communities are proving successful (personal communication with Rounaq Jahan, April 2000).

On-going Mitigation Projects

The World Bank and UNICEF are at present funding programs that incorporate government agencies, NGOs, and community participation in developing solutions. UNICEF's Arsenic Mitigation Programme includes both national and community based measures. Starting in 1996, with Bangladesh's Department of Public Health Engineering (DPHE), it embarked upon a National Arsenic Testing Programme; it is also currently supporting the development of new field technologies for arsenic analysis. In its Community Action Based Research Project, launched in cooperation with three NGOs -- The Bangladesh Rural Advancement Council, Dhaka Community Hospital (DCH), and Grameen Bank -- in Spring of 1999, alternative water sources such as rainwater harvesting systems and pond sand filters are being installed and monitored, and arsenic removal technologies are being tested for usefulness and appropriateness. The organization has organized training programs for medical workers to become familiar with arsenic induced health issues, and is working with DCH to identify and care for patients. In 1999, the government's Nationwide Communication Strategy for Arsenic, developed with UNICEF support, began its efforts to spread awareness of the dangers of drinking arsenic-contaminated water (UNICEF 2000). The organization plans to increase its efforts from supporting approximately 10,000 more villages in addition to the roughly 800 it is already working with.

In 1998, the World Bank approved a US$32.4 million interest-free loan for a Bangladesh Arsenic Mitigation Water Supply Project (BAMWSP); the government of Bangladesh contributed an additional US$9 million, and the Swiss Agency for Development and Cooperation another US$3 million. The project went into effect in February of 1999, and is to be implemented over a four year period. A nation-wide rapid emergency component will screen all wells, disseminate information to communities, and undertake rapid health surveys and identify services for diagnosis and treatment. A second component will operate in specific regions to develop alternative water supply options. Community organizations, NGOs, and BAMWSP representatives will work together to oversee operation and maintenance of new technologies. A National Arsenic Mitigation Information Center will be established to collect, interpret, and disseminate hydrogeological, water quality, health, socioeconomic, and technical data. To evaluate technology options and fund new research, a Technology Assessment Group has been established. The project's rhetoric supports active community involvement and requires communities to use some of their own resources to maintain water systems. A "no predefined blueprint" approach is being taken, with plans formulated by a project team in consultation with villagers and their NGO partners (World Bank 1999).

In conclusion, I wish to express the hope that in spite of the enormous organizational challenges that are presented by this problem and complicated by the complexity of necessary information needed to evaluate the issues and design and implement informed solutions, the efforts of dedicated and concerned researchers, NGO workers, aid agency and government officials, and the people of Bangladesh will successfully bring medical assistance to victims and safe-drinking water to all.

Works Cited


Week 1: Introduction; geochemical and hydrogeological issues

Lecturers: Martin Stute (, Yan Zheng (, and Alexander van Geen ( are involved in the Health Effects and Geochemistry of Arsenic and Lead Project, and are familiar with the earth science issues.


Week 2: Health Issues

Lecturers: Joseph Graziano ( and Habibul Ahsan ( are faculty at the School of Public Health and participants in the Health Effects and Geochemistry of Arsenic and Lead Project.



Week 3: Mitigation Efforts

Lecturers: Alex van Geen is familiar with the technology issues. Rounaq Jahan ( in the School of International Affairs is familiar with development issues in Bangladesh from a social science point of view.


Week 4: Science in Developing Countries

Lecturers: Rounaq Jahan would also be familiar with these issues. Roberta Miller ( at CIESIN and George Saliba ( in the Middle Eastern and Asian Languages and Cultures Department are both historians of science, and could lecture on general themes, even though they are not specifically familiar with the Bangladesh case.




The following websites contain excellent information on both research efforts and mitigation projects, with links to news publications, research papers, and organizations.

Contacts within CU

PPT slides of class presentation