the region of West Bengal and Bangladesh there's a problem with the water. But,
as Rose Hoban reports, an engineer from Northern Ireland thinks he has a way to
of the rock lining the underground aquifers in West Bengal and Bangladesh contains
arsenic. For millennia, the element was in a form that didn't pose a danger to
over the past three or four decades, the Green Revolution occurred. Now,
farmers apply tons of nitrogen-based fertilizers to their crops every year.
These chemicals leach into underground aquifers. Over time, they've caused a
reaction in the arsenic below ground, converting it to a form that dissolves
easily in water.
Bashkar Sen Gupta from Queens University in Belfast, Northern Ireland, says as
a result, an extraordinary number of people in West Bengal and Bangladesh now
have arsenic poisoning. That number can be as high as one in every 100 people
who are literally dying from drinking the water.
"On an average," he
adds, "five in 100 display other kinds of symptoms which is cancer-like
and in the various stages of treatment and diagnosis."
efforts to treat the water have focused on filters to remove the arsenic. But
they're slow… and they don't have a large enough capacity to adequately clean
the amount of water needed for crop irrigation.
now, Sen Gupta has come up with a low-tech solution to the arsenic problem
that's based at the village level. It involves pumping water to the surface,
aerating it to get more oxygen into it and returning it to the aquifer below.
And the method is ingeniously simple.
are using showerheads," he explains. "The showerheads spray the
water, it aerates and part of it will return using a thinner pipe back into the
same aquifer zone."
local wells use energy to draw water from underground aquifers. That energy can
be from a generator, or from a hand pump. But returning the newly aerated water
to underground aquifers requires only a pipe and gravity.
equipment here is basically very simple," says Gupta. "You just
need one pipe and few simple shower heads… plastic shower heads." The
entire set-up costs the equivalent of US $100.
the test systems Sen Gupta used, he found that one of these pumping systems
could reduce the arsenic from an area of up to 90 meters in diameter around the
pump site. He says it can treat enough water in a day to serve up to several
hundred families. And the reduction in arsenic is dramatic.
first plant that we set up – which is 25 kilometers north of Calcutta – the
first arsenic concentration that we recorded was 370 parts per billion, which
is 37 times higher than the WHO limit," Gupta reports. "It took
us about four weeks to bring it down to 20 parts per billion, and six weeks to
bring it down to about two or three… parts per billion."
Gupta is now working with Indian and Bangladeshi authorities to replicate his
water treatment scheme. He's hoping to bring more of them online in the next