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Arsenic crisis in Bangladesh

Millions of people have been drinking contaminated well water; thousands now show symptoms of chronic arsenic poisoning 

By - Wil Lepkowski 
C&EN Washington 

No country has been down and out with such depressing regularity as poor Bangladesh. Situated east of India on the Bay of Bengal, Bangladesh supports, within a space the size of Wisconsin, about 125 million largely impoverished but resilient people. Floods, disease, and malnutrition combine to buffet the society from crisis to crisis. And now it has as yet another problem: the poisoning of potentially 70 million people from arsenic present in the water drawn from millions of wells originally installed to solve shortages of drinking water. 

Quite likely, nowhere near that estimated 70 million will fall ill, certainly not die of the cancer that eventually results after several years of untreated chronic arsenic poisoning. Enough help should be on the way. International assistance organizations, though deplorably late, are beginning to respond in a coordinated way. But thousands of villagers already are affected, and across the border in West Bengal, India, where cases began turning up in the 1980s, up to 200,000 people have been diagnosed with arsenicosis. Bangladesh has an even bigger problem than India because many more people are exposed. 

But the challenge is vast because thou sands of people are showing the symptoms of years of arsenic exposure. "The overall picture is abysmally gloomy," said a May editorial in The Independent, Bangladesh's major newspaper. And a booklet on the crisis published by the Dhaka Community Hospital declares: "The Bangladesh arsenic contamination is possibly the largest mass-poisoning case in the world right now." Dhaka is the capital of Bangladesh. 

The major source of help is coming in the form of a recently announced loan of $32.2 million from the World Bank plus another $3 million from the Swiss government. The project is the first in a series of projected phases that could take up to 10 years and involve perhaps $200 million. Other international agencies are involved as well with their own funding, in addition to the Bangladesh government. 

Outside of the arsenic toxicological and geological communities, not many in the U.S. are aware of the plight in Bangladesh. U.S. relief agencies are not at the forefront of assistance efforts; Japan, the U.K., Switzerland, Denmark, and Canada are taking the lead. Most of the multilateral agencies are heavily involved, such as the World Bank, the United Nations Children's Fund (now playing catch-up, for it funded installation of a great many of the wells but never thought of testing them), the UN Development Program, and the UN Environmental Program. Those who were aware of the crisis before it became public are angry at the institutions that failed to act more quickly. 

Williard R. Chappell, a physicist who turned to the environmental sciences early in his career after receiving a National Science Foundation grant to study environmental heavy-metal contamination, says the situation is indeed urgent. A professor at the University of Colorado, Denver, Chappell is chairman of the arsenic task force for the Society for Geochemistry & Health, which he helped found. 

"I've been trying to [promote] a greater awareness of the size of the problem in Bangladesh and West Bengal," Chappell says. "There's not been a lot of publicity in the U.S., but it ranks up there with the major tragedies where we have helped nations before. And it does have some self-interest for the U.S. as well." 

Chappell has been attending, speaking at, and sponsoring meetings on arsenic contamination for several years. He became aware of the Bangladesh crisis during a 1993 arsenic workshop in Maryland. There he met Dipankar Chakraborti, director of the School of Environmental Studies at Jadavpur University in Calcutta, India, near the Bangladesh border. Chakraborti was already working to alleviate the existing arsenic problem in West Bengal, but he discovered to his shock that the problem in Bangladesh was potentially far worse. 

Chappell, colleagues in his field, and the U.S. regulatory community are in the midst of developing a new arsenic standard for U.S. drinking water. The current level is 50 ppb, now considered too high. A proposal is due Jan. 1, 2000, and the final standard will be set for promulgation a year later. 

The issue is politically hot -- environmentalists took the Environmental Protection Agency to court for dragging its feet-because pressure is intense to adopt the World Health Organization's (WHO) guideline of 10 ppb. WHO's new standard was influenced by the crisis in Bangladesh. U.S. industry -- citing costs and already worried about Superfund cleanup expenses -- is largely opposing anything under 30 ppb. EPA says it wants to keep costs down for the economic benefit of rural areas, where arsenic contamination is more common. It has sent several teams to Bangladesh for data that might be of help in determining a reasonable standard. 

Chappell would like the international scientific community to at least become more broadly aware of the problem in Bangladesh. "They need to help design a long-range plan that is feasible," he says. "They need to evaluate the interim solutions such as various treatment schemes. They need to develop methods for treating patients. And as this is going on, they need to do research to better understand how the problem came about and develop a better understanding of the health effects and underlying mechanisms." 

The wells-thousands and thousands of them-were installed starting in the late 1960s as the answer to Bangladesh's severe surface-water pollution problem, which in fact continues today. But what appeared to be a godsend became one more curse for Bangladesh. Perhaps as many as half of the 4 million wells drilled are contaminated with arsenic in amounts that exceed 50 ppb. Levels 10 times higher are almost routine in contaminated areas. 

Fortunately, chronic arsenicosis is reversible when treated early enough. Fresh water, vitamins, and drugs such as D-penicillamine and dimercaptosuccinic acid (not a practical option yet; they are considered too expensive for use in Bangladesh) are sufficient to bring about a cure. But once cancer begins to develop after eight to 10 years, or livers and kidneys begin to deteriorate, the victims are beyond help. Poor nutrition renders villagers more vulnerable then they otherwise might be. 

The more toxicologically active form of arsenic is its trivalent arsenite, followed by the pentavalent form. Arsenic, which is the same group in the periodic table as phosphorus, resembles that element in its metabolic patterns. A fact sheet issued by a University of Florida information service says it acts in two major ways in mammalian systems --by reversible combination with thiol groups in tissues and enzymes, and by substitution of phosphorus in critical systems such as oxidative phosphorylation. 

The source of the arsenic is almost certainly pyritic (iron sulfide) sedimentary rock laid down over millennia by the rivers -- mainly the Ganges that runs down from the Himalayas to form that fertile, watery delta so agriculturally productive but notorious for its annual flooding. Many theories, all tentative, have been proposed to account for the release of the arsenic into Bangladesh aquifers. Early on, it was proposed to be oxidation of the rock by atmospheric oxygen caused by lowering of the water table, forming soluble arsenic containing oxypyrites, 

Lately, though, another theory has come forth, in a paper published in September in Nature [395, 338 (1998)]. The report was written by a group headed by geologist Ross Nickson of University College, London. The authors believe the critical mechanism proceeds not in an oxygen environment but in an anoxic one, a condition to be expected at the depths to which wells are drilled. In that environment, arsenic-rich iron oxyhydroxides are present, formed out of the base-metal sulfides laid down millennia ago within the Ganges basin. These are reduced to the soluble state by organic matter simultaneously present in that sedimentary geology. The reduced material, when exposed to aquifer water, leaches the arsenic into solution and thereby produces the contamination. 

The authors suggest that "simple aeration" of the groundwater might do the trick of removing arsenic. The aeration would induce the formation of iron hydroxides that would scavenge the arsenic and precipitate as arsenic-rich iron hydroxide. They say the treatment could be performed in villages, although the disposal of the arsenic-loaded precipitate "would require special arrangement." But, they continue, "this would be preferable to either the widespread poisoning that now exists or a return to the use of [microbe]-contaminated surface water." 

Simple, low-cost techniques -- many, in fact, involving iron-are being sought and have come forth for the detection and removal of arsenic by villagers themselves. One removal technique has been developed at the University of Connecticut by Nikolaos P. Nikolaidis with colleague Jeffery Lackovic and Gregory Dobbs of United Technologies Research Center. The research was done at a site in Maine for a company Nikolaidis says he is unable to disclose. The groups have a patent pending on the technique. 

It involves use of iron filings mixed with sand installed in tubes through which the well water, spiked with barium sulfate, is passed. The elemental iron is oxidized, creating a solution devoid of oxygen. The various arsenic species are reduced by the zero-valent iron of the filings, and in combination with sulfates, the arsenopyrite precipitates and remains trapped in the filter column. 

Nikolaidis says the technique is inexpensive. Sand is cheap at about $10 a ton, and iron filings sell in the U.S. for about $350 a ton. He says the filter brings arsenic concentrations down to less than I ppb. He hopes those who manage the World Bank's new program will test it. The project is incorporated in the newly established Harvard University Arsenic Project, which consults with several assistance organizations. 

It is impossible to say when, or whether, Nikolaidis' technique, along with others, will be tested in Bangladesh. So for now, even simpler methods are being used. One involves dipping alum (aluminum potassium sulfate) wrapped in a cloth in well water for a few seconds. An arsenic precipitate forms overnight, and the solid can be filtered through cloth. By this process, it is reported, 70 to 80% of arsenic is removed from the water. 

Information like this is what the World Bank will be seeking as it gears up to tackle the problem. The challenge is formidable and complex because the bank must help the government see to it that the efforts are well organized and multipronged and can cut through the maze of agencies, multilateral assistance groups, and nongovernment organizations that permeate Bangladesh. Corruption, too, is ever present, requiring watchful auditing mechanisms to see that the funds are directed properly. A World Bank report on a new vision for Bangladesh labels its government apathetic, secretive, and unaccountable." 

The bank's program involves a number of approaches, including research on the sources Of the arsenic, training villagers in testing their well water with instruments still under development, treating those already affected, establishing a water-resources policy in the country that takes into account this new water-related danger, and bringing in fresh water immediately. 

Also, says project manager Nadim Khouri of the bank's South Asia division, funds will be used to involve Bangladesh's academic science community, which has never been organized to contribute to the country's formidable development problems. Indeed, as Chakraborti points out, very few development projects have ever required actual management of some aspects by villagers themselves. "The World Bank may sanction billions of dollars,' Chakraborti stresses, "but that money will be useless if grassroots people are not involved in that work.' 

The World Bank plan also calls for development of baseline data on the contamination and establishing mechanisms for continuous monitoring. A National Arsenic Mitigation Information Center will be set up, in the plan's words, to "collect, manage, interpret and disseminate all relevant hydrogeological, water-quality, health, socioeconomic, and technical information.' A technology assessment group will be established "to review technology options as well as social and economic project approaches in an objective and impartial way." 

A hydrogeological study has begun to reconstruct the origin and extent of arsenic release into groundwater. A laboratory calibration and verification system will be set up to ensure analytical quality control. Funds, in other words, will be used to pursue research on all aspects of the arsenic problem. 

So the World Bank's plan is, if anything, comprehensive. Its point, Khouri explains, is to position the pertinent elements of the system in the right relationship to one another-something brand new in science and technology policy for developing countries. He says he is determined that the bank effort will be a pioneering one, the first step toward a more extensive enterprise being planned by the bank and its advisers. If there is such a phenomenon as "barefoot science policy," it could be unfolding in Bangladesh. 

The arsenic issue also forces planners to think big and assess past mistakes. Khouri emphasizes that the arsenic problem is really a subset of, and catalyst for, a comprehensive water policy for Bangladesh, including a science policy that would facilitate a research program for the issue. At the moment, the country, in contrast with India, has no research community to speak of that can be harnessed through international networking. Khouri says he would like to see a National Science Foundation established in the Bangladesh government that would function also as an Office of Science & Technology Policy to advise the prime minister on current and emerging issues. 

As Chakraborti says, there is little public appreciation for the way water, sanitation, hygiene, and health are interrelated. "Research activities are not integrated into project development to improve the design of projects," he says. "Water-quality monitoring and surveillance receive little emphasis. Laboratory findings are not incorporated into operational activities, and the quality of laboratory analyses is questionable." The various governmental jurisdictions, he says, generally have little connection to one another. And he says too few chemists have been brought on to help in aspects of the problem. 

But the government appears to be turning itself around. Late last year, for example, it established a ministerial water policy coordination group and passed a law that set up organizations at the village level with elected permanent committees to oversee water and sanitation. The World Bank wants the arsenic project to be, in the words of its plan, "a role model for the new institutions that will emerge over time when decentralization to local government takes root." 

Chappell, who thinks the possibility of a two-year "crash program" is worth looking into, calls the bank loan a "drop in the bucket." He adds, "If there are a million tube wells with high arsenic concentrations, $34 per tube well isn't going to go too far. " What is needed, he says, "is a complete, specific inventory of problem areas, then remediation activities applied immediately after problem areas are found. Meantime, an ambitious public-health screening program needs to be put in operation or accelerated." 

Khouri agrees with everything Chappell says, except for the speed. "You can't throw money at the problem," he says. "If we spend a lot of money now, the government will certainly find ways of spending it. But we want to make it work. There is no technological magic bullet as yet. We want to learn from the mistakes we made previously. Every year we will be reviewing progress in the project." 

Chakraborti, bitter over his experiences with official delay and bureaucratic bungling, has his eye ever on the practical. "We should learn from West Bengal's experience," he says. "There the calamity was detected in 1983, but nothing was done until 1990. Because of this negligence, the problem has been aggravated, and more and more people used contaminated water. If safe water sources can be provided, the majority of the population can be saved. 
This special feature article appeared in November issue of Chemistry and Engineering (C&EN) Newsletter of American Chemical Society (ACS).