Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Inaccurate arsenic test kits jeopardize water safety in Bangladesh and India

19.11.2002


Thousands in southern Asia could be drinking arsenic-contaminated water from wells that are falsely labeled safe, while precious good water sits untapped in wells that are wrongly marked unsafe — a dire disparity for countries where water can be more valuable than gold.



A new study of wells in Bangladesh and West Bengal, India, suggests the arsenic test kits used by field workers are frequently inaccurate, producing scores of incorrectly labeled wells. The findings were published this month on the Web site of Environmental Science & Technology, a peer-reviewed journal of the American Chemical Society, the world’s largest scientific society. The print version of the paper is scheduled for the Dec. 15 edition of the journal.

Researchers analyzed 2,866 water samples from wells that were previously labeled by field workers. They found that a large percentage of the wells were labeled erroneously.


Shallow wells, known as tubewells, are commonly used in Bangladesh and India to avoid the region’s surface water, much of which contains bacteria that can cause waterborne diseases like cholera. Beginning in the 1970s, international aid organizations dug millions of tubewells, and the program was basically successful in providing bacteria-free water. But officials soon found that the tubewells were reaching groundwater containing high levels of arsenic.

Arsenic is a slow poison; studies have linked long-term exposure to several types of cancer, according to the U.S. Environmental Protection Agency. The World Health Organization advocates a maximum arsenic level in water of 10 micrograms per liter — the standard currently used by the EPA — but many developing countries still use a standard of 50 micrograms per liter.

By 1993, the Bangladesh Department of Public Health Engineering had reported widespread signs of arsenic poisoning and blamed tubewell water. WHO called it the largest mass poisoning of a population in history. Similar problems have recently surfaced in other countries in the region, including India, Vietnam, Cambodia, Nepal and Myanmar (formerly Burma).

In 1997, the World Bank, WHO, UNICEF and other international organizations undertook a massive project to test every tubewell in Bangladesh and the surrounding area using field kits. Many wells were labeled with paint to indicate their viability: green for safe water (containing under 50 micrograms per liter of arsenic) and red for unsafe water.

"We have been surveying in arsenic-affected areas of Bangladesh since 1996," says Dipankar Chakraborti, Ph.D., head of the School of Environmental Studies at Jadavpur University in Calcutta, India, and lead author of the paper. He and his colleagues often heard stories from villagers about mislabeled wells. One villager reportedly brought two glasses of water for testing to field workers who had labeled the wells; one glass was declared safe by the workers and the other was declared unsafe. The villagers then proceeded to assault the workers, Chakraborti says. Both samples had apparently been taken from the same well.

The researchers began testing tubewells themselves with a technique called flow injection hydride generation atomic absorption spectrometry (FI-HG-AAS) — a fast and sensitive method performed in a laboratory setting. They found random errors in the labeling of tubewells, which led them to begin the systematic study reported in the current paper.

They found that nearly 50 percent of the wells painted red by field workers actually contained safe drinking water, according to their lab technique. Only 7.5 percent of the green wells turned out to be unsafe.

The point, the researchers emphasize, is that the field kits appear to be random and qualitative — not appropriate for large-scale testing initiatives with such important health, economic and environmental impacts.

The field kits are difficult to read with precision and often are not suitably accurate for this type of measurement — the majority of the analyses in Bangladesh were done before 2000, using a test kit with a minimum detection level of 100 micrograms per liter.

Chakraborti recommends using the FI-HG-AAS analysis because it not only provides more accurate readings, but there are also environmental impacts from the field kits that are not a concern in the lab. The field kits require relatively large quantities of toxic chemicals that must be disposed of, he says, but the lab technique uses a "micro-assay" technique with much less need for chemicals.

The lab technique can also be less expensive than the field kit method, Chakraborti says. "Cost is an important consideration but [it] requires comparison with the even higher cost of falsely labeling a well as unsafe," the researchers write. "Given the scarcity of uncontaminated water the mislabeling of 50 [percent] of safe wells has a major socioeconomic impact."

The School of Environmental Studies is a self-funded institute within Jadavpur University, which is operated solely on money earned from selling its expertise.

Beverly Hassell | EurekAlert!
Further information:
http://www.acs.org/
http://pubs.acs.org/estnews

More articles from Health and Medicine:

nachricht A 'half-hearted' solution to one-sided heart failure
24.11.2017 | Boston Children's Hospital

nachricht New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New proton record: Researchers measure magnetic moment with greatest possible precision

High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons

The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...

Im Focus: Frictional Heat Powers Hydrothermal Activity on Enceladus

Computer simulation shows how the icy moon heats water in a porous rock core

Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

IceCube experiment finds Earth can block high-energy particles from nuclear reactions

24.11.2017 | Physics and Astronomy

A 'half-hearted' solution to one-sided heart failure

24.11.2017 | Health and Medicine

Heidelberg Researchers Study Unique Underwater Stalactites

24.11.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>