Newswise — Arsenic, the "king of poisons" slipped to royalty throughout the ages, now poses a grave danger to at least half of the rural population of Bangladesh and other countries with similar geology, such as India, Vietnam, Cambodia and Mexico.
"We are working on borrowed time," said Hossain, a Tennessee Tech University civil and environmental engineering professor. "We must accelerate priority testing of the rural drinking water system in order to reduce the risk that arsenic poses to villagers."
About 50-60 million people in Bangladesh are exposed to toxic levels of arsenic through water drawn from shallow wells. Hossain says there could be as many as 20 million wells in the rural countryside, making it virtually impossible to test every well comprehensively because of the time and money involved. Arsenic in the wells' water is largely the result of minerals dissolving from weathered rocks and soils. In the 1960s, farmers and villagers began drilling shallow wells, which were cheaper but more susceptible to arsenic buildup, after the government encouraged a switch from surface water to ground water for drinking.
In the early 90s, the poisoning reached epidemic scale and continues to worsen. According to the World Health Organization, long-term exposure to arsenic via drinking water causes cancer of the skin, lungs, bladder and kidneys, as well as skin changes such as pigmentation abnormalities and hyperkeratosis, a thickening of the skin.
Hossain and colleagues at the University of Connecticut, University of California-Davis, and Bangladesh's Rajshahi University and Engineering University have set a goal to devise an efficient and low-cost way to identify and shut down unsafe wells.
Testing wells is expensive and time-consuming; accurate testing requires that each sample be sent to a quality environmental lab equipped with an expensive Atomic Absorption Spectrophotometer. The government has opted instead to test wells by inexpensive hand-held kits (each costing about a dollar and requiring 30 minutes of testing time). These kits, however, tend to have large errors in reporting the results.
"For one particular brand, we observed that the kit had only a 10 percent chance of correctly detecting a safe well. This means that 90 percent of the time the villagers use the kit they are likely to get the false impression of an unsafe well being safe. It's akin to an HIV-infected person being tested negative and told not to worry anymore," said Hossain.
The rampant and large-scale use of such kits without knowledge of their reliability is alarming not just for Bangladesh, but for other developing countries that are considering these inexpensive devices to manage their arsenic problem.
"Another issue currently overlooked by researchers is the need to propose solutions that fit into the social fabric of how rural people collect water," he said. "Recent social studies indicate that villagers would rather travel far away once a day to collect their daily requirement of safe drinking water than be burdened with a water treatment system that is difficult to maintain."
Hossain and his colleagues are currently working on an adaptive model that can pick up patterns on how the arsenic varies so that only a few wells have to be accurately tested in order to predict if others are safe or unsafe. The group employs two sister theories, Chaos and Fractals, which some researchers doubt can be applied to this problem.
"Even though the patterns may seem random at first sight, mother nature often times has a tendency to repeat itself on the basis of a 'code' that lurks behind this apparent randomness " the order hidden in randomness is called Chaos.
"The theory of chaos means that once the code is identified, we should be able to look at a relatively fewer number of accurately tested wells and be able to improve prediction of well characteristics on a larger collection of untested wells," he said.
"Now, think of a head of cauliflower, you pull one section out and it looks very much like a small version of the next larger section and the same all the way to the whole. This describes the phenomenon called Fractals," said Hossain. "We learn about the whole by studying the smaller sections.
"By flagging a safe cluster of wells, or by shutting down unsafe clusters, we can provide villagers a rapid, socially and financially more convenient choice to travel to a safe wells," he said.
"Our recent work has revealed that it is indeed possible to connect the theory of chaos to improve prediction characteristics of untested wells. This is probably something that the scientific community has not witnessed up to now as far as the arsenic problem is concerned," said Hossain.
So excited is he and his team of collaborators, that Hossain cannot wait to present his team's recent findings at the upcoming American Geophysical Union Meeting in December this year at San Francisco.
"Such results are always bound to raise a few eyebrows among skeptics and believers of chaos theory alike," chuckled Hossain.
As a firm believer in serving calamity affected society, Hossain emphasizes that when a large portion of the rural population continues to suffer from the arsenic calamity, the more fortunate ones with time to brainstorm and drink arsenic-free water have the responsibility to critically assess any novel approach until a long-term structural solution is found for Bangladesh.
Interested readers can find more information about Hossain's work at http://iweb.tntech.edu/fhossain.
RSS