A race to fix a 30-year-old 'solution'
In Nepal's agricultural flatlands, women line up at village wells with earthen or metal pots. The water they pump out is sweet and apparently clean. Tragically, it's also often laced with arsenic.Skip to next paragraph
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In a scene repeated in more than a dozen countries from Hungary to Chile to the United States, tens of millions of people are drinking from arsenic-tainted wells. Ironically, these wells were dug from the 1970s to the present to provide clean water. Some have called it the largest mass poisoning in history.
Now, researchers are racing to fix this three-decade-old mistake.
"The technology isn't rocket science," says Susan Murcott, an engineering professor at the Massachusetts Institute of Technology. "But we have to translate that knowledge into a system that is viable in these different social settings and in decentralized settings."
It's been anything but easy.
For seven years, Ms. Murcott and her graduate students have traveled to Nepal to devise a foolproof arsenic filter. Such a filter must be cheap, easy to make, and simple to maintain - and local people must want to use it, too, she explains. So far, her team has built and tested seven promising technologies, yet all have failed in one way or another. Some were too costly, one was too heavy, still others didn't filter water fast enough.
Finally, last year Tommy Ngai, an MIT graduate student, bought a round plastic bin at a street market in Kathmandu, Nepal. He and the team filled it with layers of sand, brick chips, gravel, and the magic ingredient - a layer of locally bought iron nails, which chemically bind arsenic to them. The filter may just be the MIT team's silver bullet, a combination arsenic and biological filter. Cost: less than $16.
"We're hopeful we may have found a solution," Murcott says.
A solution is needed. Besides 3 million in Nepal, many millions more drink arsenic-tainted well water in India, Peru, Ghana, Nicaragua, Vietnam, China, Argentina, Mexico, Chile, Taiwan, Hungary, Philippines, New Zealand, Mongolia, the United States, and other nations, Murcott says. The problem is worst in Bangladesh. If the MIT arsenic filter was used there, it might relieve some 35 million people who drink the tainted water - about a quarter of the population, according to published estimates.
Still, variations in water chemistry from country to country make a one-size-fits-all solution difficult. So Murcott's filter for Nepal may not work as well in Bangladesh.
Others are also working on the problem, spurred perhaps by the announcement last month of the first "Grainger Challenge Prize." The National Academy of Engineering in Washington, D.C., is offering $1 million for the first device that can remove arsenic from groundwater and also leap the practical hurdles Murcott's team has faced for years.
Two groups, one at Harvard University in Cambridge, Mass., and another at Columbia in New York, are pursuing well-water arsenic solutions. So are scientists at Lawrence Berkeley National Laboratory, the Centers for Disease Control and Prevention in Atlanta, and the World Bank. At least 50 arsenic-removal technologies are already available, but face various challenges, Murcott says.
Ironically, the problem dates back some three decades in a well-meaning but botched attempt to keep villagers in developing countries from drinking - yes - tainted water.
For years, health authorities had agonized over villagers drinking from bacteria-infested ponds, streams, and lakes. In the 1970s, the United Nations, World Bank, and others mobilized to fix the problem with "tube wells" - a simple and relatively cheap solution that tapped biologically pure groundwater around 20 to 75 feet deep. Within a few years, millions of tube wells were drilled across the developing world.
Things seemed better at first. Villagers, especially women and children who had lugged water from streams and rivers, walked shorter distances and had time for other pursuits. In Bangladesh, health problems from surface water diminished.
Unfortunately, nobody thought to test the water for arsenic.
"We thought 20 years ago that these tube wells were a nice idea, the water was nice and sweet - well, it was because that's the arsenic taste," says Richard Wilson, a Harvard physicist and expert pursuing his own arsenic solution. "This catastrophe is something the whole world is partially responsible for. We here in the US and in England were advising the Bangladeshis. Nobody told them to test for arsenic."