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Poisoned Waters: Bangladesh Reaches to Science for a Solution

Click here for a more detailed report on this issue. (pdf file 676 KB)
Sonargaon, Bangladesh. It wasn’t supposed to be this way—the idea and the intentions were genuine. Faced with disease-contaminated surface waters, aid agencies, government bodies, and millions of villagers tapped groundwater as a source for drinking and domestic use all across rural areas of Bangladesh. Beginning in the early 1970s, millions of tubewells were sunk into the shallow water table, and handpumps became a central feature of a better life for the rural poor.

Up to 50 million people in the towns and villages of Bangladesh may be exposed to arsenic levels exceeding the WHO limits. This man is suffering from advanced arsenicosis.

In Nilkanda village, about two hours drive from the capital city, Dhaka, a housewife, Monwara Begum, recounts how a tragedy of monumental proportions began to unfold. “Handpumps helped us to avoid the diseases in the pond. But after drinking from the pump over many years, my husband fell ill with arsenic poisoning. We use a filter system now for all we drink, but I’m not convinced it is very safe.”

In another nearby home sits a man thin and listless. His hands and feet are pocked with callous-like growths, a tell-tale sign of arsenicosis. “He continues to drink from the contaminated well,” explains Zabed Hussain, an environmental researcher who has spent the last four years grappling with the disaster in this subdistrict. “He doesn’t use any filter because he’s convinced he doesn’t have many more days to live.”

The filter system being used in Sonargaon has been subsidized by the Mr. Hussain’s agency, BRAC—the Bangladesh Rural Advancement Committee, the largest non-governmental development organization in the country, with a long and successful history of improving conditions in this poverty-wracked nation of 130 million.

“More than 60 per cent of the wells in this subdistrict are contaminated with arsenic and unsafe to drink,” says Mr. Hussain “Many people still drink the bad water from the wells. The alternatives cost them time and money, and people here face extreme poverty.”

With support from UNICEF, BRAC’s staff has been working hard to field-test a wide variety of low-cost water treatment systems and supply alternatives in village communities—such as arsenic filtration devices, rainwater harvesting from rooftops, hand-dug wells, and deep tubewells. Wells throughout the area have been tested for arsenic using a portable kit, and contaminated wells and pumps have been marked with red paint signaling danger.

“The arsenic can be removed,” explains Preben Gondolf, who oversees water sector aid programmes supported by the Danish Embassy. “The real issue is: Can arsenic be removed cheaply at the village level.”

The efforts of BRAC and numerous other public, private, and international organizations are helping to alleviate what CBS television in 1999 called the “greatest disaster in human history.” But far more will be needed to provide a lasting solution and an end to widespread human suffering.

“Arsenicosis is hard to diagnose and there is no known cure or treatment,” explains Han Heijnen, an environmental health advisor with the WHO. “We know that continuous exposure is a sure cause of early death. Arsenic poisoning at the levels we’re seeing in Bangladesh will take 10 or 20 years off a person’s life, without any doubt.”

A wide variety of arsenic mitigation strategies and technologies are being tested at the village level. Handpumps that are determined to be safe from arsenic contamination are painted green; dangerous ones are red.

Heavy metal contamination was not even considered in Bangladesh until evidence of arsenicosis began to emerge in the neighbouring Indian state of West Bengal in the late-1980s. Arsenic contaminated wells were first confirmed in Bangladesh in 1993 and a global call for assistance was broadcast. The first comprehensive, nationwide testing of wells was conducted by the British Geological Survey (BGS) in 2000. BGS determined that 27 per cent of all shallow tubewells (less than 150 metres deep) were contaminated with levels exceeding the national standard for drinking water. Fully 46 per cent of these shallow wells exceeded the WHO standard. And somewhere around 5 per cent of the deep tubewells are also contaminated beyond the WHO limits.

The nationwide numbers are startling. There are 6–11 million tubewells in the country, and some 1.5 to 2.5 million wells are contaminated, even by the less conservative Bangladesh standard. Altogether, some 35 million people are believed to be exposed beyond the national standard and 57 million are exposed to arsenic concentrations above the more stringent WHO standard.

With nearly half the country’s population facing the threat directly, it is crucial to understand the patterns of contamination. But it is not that simple: “We know it’s not the depth of the well alone that determines its safety now or in the future,” says Mr. M. Khaliquazzaman, an environmental scientist working with the World Bank. “Tapping a deep well may work for a village, but is it safe and sustainable for a city of a million? That’s what we still don’t know.”

One major effort underway to analyze and address the arsenic problem at the national level is the Bangladesh Arsenic Mitigation Water Supply Project (BAMWSP) backed by US$ 40 million from the World Bank and Swiss Agency for International Development. Launched in 1997, BAMWSP aims to provide water supply relief for rural people and to enhance scientific analysis of the scope of contamination. Established as a distinct organization from existing government institutions, the project has had a slow start—suffering from bureaucratic delays, lack of coordination with other water sector efforts, and a lack of sound scientific and technological information.

“Finding solutions to the contamination that can be implemented at the community level has been a complex process,” according to project director, Abdul Quader Choudhary. “It took nearly 30 years to get universal coverage of drinking water supplies using handpumps. We have identified mitigation technologies that can work and are affordable by the poor. But we’ve still got a long way to go in solving the problem in a systematic way.”

Determining arsenic concentrations in water is not a simple matter scientifically, although simple test kits produced by the U.S. drug giant, Merck, began to be used to measure village well contamination in mid-1990s. “Testing and analysis of arsenic contamination is technically complex, difficult, and expensive,” explains Dr. Abul Hasnat Milton, chief of the arsenic unit in the NGO Forum for Drinking Water Supply and Sanitation. With assistance from the Danish Embassy, Dr. Milton’s water quality testing laboratory in downtown Dacca is one of the country’s most sophisticated, and has analyzed more than 25,000 samples for the government and aid agencies.

Testing for arsenic contamination is complex and time consuming. Continuing capacity building and quality control are essential to obtain reliable results. This testing laboratory run by the NGO Forum gets financial aid from Denmark.

“There is still a great need to improve arsenic testing,” says Mr. Khaliquaz
zaman of the World Bank. “There are
26 laboratories doing tests across the country, but only a third of them are capable of delivering results of an acceptable standard.” The WHO and the IAEA have been assisting in this area through a laboratory quality assurance programme.

Compounding the uncertainties in the arsenic mitigation work of the World Bank, BRAC, UNICEF, and others is a lack of basic knowledge about the movement of ground-water, and the location and mobilization of arsenic in water supplies. Again, it is not a simple picture.

“The geology and hydrology of Bangladesh is very complicated due to the nature of its underground structures,” says M. Nazrul Islam, Director General of the Geological Survey of Bangladesh. “Try to imagine multiple layers of Himalayan sediments deposited over tens of millions of years by shifting rivers, tides, and floods. The sediment layer is up to 20 kilometres thick near the Bay of Bengal. Aquifer movements remain poorly understood.”

Mr. S. K. M. Abdullah, who chairs a national expert committee advising the government, elaborates, “The Bengal Delta is more complex than the Mississippi, the Rhine, or the Senegal River deltas. It’s really a composite—three deltas in one. We know that water older than 20,000 years is largely uncontaminated, but you can’t just drill down to a certain depth and assume it is safe.”

What is clear from all of the experts is that Bangladesh needs science for a solution: “What’s really called for is analysis of deep aquifers on a country-wide basis,” says Mr. Khaliquazzaman. “Isotopic analysis can play a critical role in understanding and addressing the arsenic contamination problem.”

Beginning in 1999, the IAEA has been working with the World Bank BAMWSP project team to utilize isotope hydrology techniques to enhance knowledge of groundwater and aquifer dynamics. This includes investigating whether deep aquifers will remain arsenic free over the long term if they are developed as alternative sources, and how other deep aquifers may have been contaminated through mixing of deep and shallow reservoirs.

“Until very recently, the hydrogeological characterization in Bangladesh was being conducted through multiple institutions and agencies using primarily non-isotopic techniques,” explains Pradeep Aggarwal, Head of isotope hydrology for the IAEA. “The integration of isotope techniques has provided the required information rapidly and at a much lower cost than previously possible. Now we are expanding the application of isotopic techniques countrywide.”

The investigation into a sustainable solution currently underway will serve as a critical and strategic investment for both Bangladesh and the Asia-Pacific region. “The people of Bangladesh will be struggling with this problem for the next 30 years,” explains WHO’s Han Heijnen. “And we are only now uncovering the true extent of arsenic poisoning in India, China, and other neighbouring countries.The contamination could easily reach 100 million people in Asia-more than the numbers affected by HIV-AIDS”

  Managing Water Resources in an Era of Scarcity


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Bay of Bengal

“Isotopic analysis can play a critical role in addressing the arsenic contamination problem.”
M. Khaliquazzaman,
World Bank

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