Millions of people in Bangladesh continue to drink water from arsenic-contaminated tube wells, the most common source of drinking water in the country, according to health specialists.
A 2001 survey by the British Geological Survey estimated that more than 50 million people in Bangladesh drank water from such wells – that figure is closer to 100 million now, says Mohammad Quamaruzzaman of Dhaka Community Hospital.
According to scientists and water experts, arsenic-contaminated drinking water in densely populated Bangladesh could be described as the worst mass poisoning of a population in history.
In Bangladesh the acceptable level of arsenic in drinking water has been set at 50 parts per billion (PPB) or 0.05 microgrammes per litre of drinking water, while the approved global standard set by the World Health Organization (WHO) is 10PPB.
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“If the WHO’s contamination level of 10PPB (0.01microgramme/L) is accepted in Bangladesh then the percentage of contaminated tube wells could be about 70 to 100 percent in some of the endemic arsenic-contaminated areas,” claimed Mahmuder Rahman of Dhaka Community Hospital.
After the discovery of naturally occurring arsenic in ground-water in Bangladesh in the early 1990s, initial work focused on awareness-raising and tube well screening to identify the extent of the problem, explained Rick Johnston, water and sanitation specialist for the UN Children’s Fund (UNICEF).
“More than five million tube wells have been tested and it is known that approximately 20 percent of the wells in the country exceed the government-approved limit of 50 parts of arsenic per billion units of drinking water,” Johnston said.
Photo: Wagtech International
|The Arsenator is the world's first digital field instrument capable of measuring arsenic in water down to ppb levels|
Since then, efforts to address the problem have shifted towards providing alternative sources of safe water in the worst-affected areas.
Since 2000, more than 100,000 new water points (tube wells, dug wells, rain water collectors, pond sand filters, etc) have been installed.
“But many people still remain exposed and Bangladesh is in danger of missing the safe water component of Millennium Development Goal (MDG),” Johnston warned.
Bangladesh hopes to halve the proportion of people without sustainable access to safe drinking water and sanitation between 1990 and 2015.
“Five million of the country’s 10 million tube wells have been tested and the remaining five million need to be tested. The only way to test so many wells in such a short time is through field testing kits,” Johnston said.
Yet field kits used in the 1990s have proven inefficient.
However, in 1998, Walter Kosmus of Karl-Franzens University in Austria developed a sensitive, accurate and user-friendly arsenic detector kit which he called the Digital Arsenator, the first digital field instrument capable of measuring arsenic in water down to ppb levels.
Photo: Shamsuddin Ahmed/IRIN
|Arsenic-contaminated tube wells are marked red. Water from these wells can be used for household use but not for drinking|
“The Digital Arsenator is better because instead of depending on the naked eye to determine arsenic content by comparing colours between contaminated water and various shades on a colour chart, it gives digital reading of actual arsenic contamination in the water,” Johnston said.
The machine combines laboratory accuracy with field portability, accurate down to PPB levels and the critical range of 2-100 PPB, providing results in just 20 minutes.
Moreover, it reduces reliance on costly, lab-based analytical techniques. It is simple and easy to operate, and environmentally friendly.
“Arsenators are good because they are portable. There are other machines that give accurate readings too, but those are big and heavy and cannot be carried to the field,” agrees engineer Mohammad Ibrahim, deputy director of a government-UNICEF project on water and sanitation. “With an Arsenator in hand, one can get the exact reading of arsenic in water sitting right at the site,” he said.
The machine costs about US$2,000. UNICEF Bangladesh has already purchased 50 to use in collaboration with its government and NGO partners.