During the 1970s, international aid agencies came up with a brilliant plan to stem a plague of water-borne illnesses in the Asian country of Bangladesh. They would underwrite the installation of wells in disease-troubled villages, tapping into the cleaner ground water below.
They would use simple, relatively inexpensive tube wells, place thousands of these over-sized drinking straws into the shallow aquifers. And these straws - millions of them - would suck up the cleaner, microorganism free water in healthy abundance.
At first, it seemed to work like a blessing. Infant mortality rates dropped by 50 percent as the rate of dysentery, typhoid and chlolera dropped. But by the mid-1990s, a strange epidemic of other illnesses began to appear - some symptoms rather like cholera (lethargy, severe stomach pain, nausea and diarrhea), but others wickedly their own: such as a roughening and darkening of skin, a corrosion appearance of lesions on hands and feet:
In fact, as a team of increasingly angry researchers from adjacent India concluded in 1995: classic symptoms of arsenic poisoning.
The element arsenic is one of the oldest known naturally-occurring poisons on Earth, found scattered through rocky beds of minerals around the place. It was reportedly identified by the Roman Catholic scholar and alchemist Albertus Magnus (also known as St. Albert the Great) in 1250, while he was heating the mineral orpiment, which turns out to be rich in both arsenic and sulfur. As an ingredient in the complex recipe that makes up the Earth's crust, arsenic is relatively rare - about 1.5 parts per million over all - and usually brought to the surface as a waste byproduct of mining other ores.
Oh, but the problem is that that it's not distributed evenly around the planet. Arsenic-dense mineral deposits cluster unevenly. We find them when illnesses appear, usually, beneath the Ganges River Delta, where Bangladesh and the West Bengal province of India sit, in Thailand, Taiwan, tracked across mainland China, in the Latin American countries of Chile and Argentina, in states of the American West such as New Mexico and Nevada.
And what happened in Bangladesh is that all those well-meaning wells, those nifty technological straws, pulled water, contaminated by the surrounding mineral deposits, right into the homes and lives of millions and millions of people. In fact, last week, the World Health Organization called it "the largest mass poisoning of a population in history."
This followed a rather horrifying study published in the British medical Journal, Lancet, which concluded that some 77 million Bangladeshi had been exposed to toxic levels of arsenic and that such exposure was responsible for more than 20 percent of the deaths in a population study group from the region. "The results of this study have important public health implications for arsenic in drinking water," the authors noted, with some understatement.
If you return to the original idea - finding a source of water uncontaminated by evil pathogens - the original hopes are still obvious. Easy to say, very easy to say, in hindsight, that a good geological analysis might have prevented the grief to come. But it's also true that surface water remains often unsafe and the source of many illnesses in this region. There's an element, at least for now, of being caught between the proverbial rock and hard place, even while we can hope for better answers.
So for the moment, let's consider this a cautionary tale. A reminder that good intentions don't always mean good health. That we live on a dangerous planet, both above ground and below. And that we are almost never as smart as we think we are.
Did they not test the water when they first started installing the wells?
It is sad to know what happening to the Bangladesh people. Even simple resource like drinking water could get them into risk.
Has anyone done the sums to estimate how many people would have died drinking the contaminated water they used before the wells were dug, compared with the number who died because of the wells? While the arsenic poisoning is an awful thing to have happened, it is quite possible that the alternative might have been even worse.
Scientific American published an article about the problem and possible remedies already in August 2004.
Wikipedia has also some things to say.
Some of the problem is that that tube wells aren't made to go as deep as, say, municipal wells and they've been drawing on a shallower and more arsenic contaminated layer of ground water. A lot of assumptions were made based on the water from existing deeper wells so, to answer your question, which - to answer your question - is a major reason that full-scale testing for arsenic wasn't done.
The arsenic may not have been apparent when the wells were first used. Often arsenic is present as sulfides which are esentially completely insoluble. It is only when water is drawn from the well that the anoxic sulfidic water were the arsenic containing sulfides are present gets replaced by oxygen containing water from the surface that the sulfides oxidize and the arsenic is liberated.