Law of unintended consequences squared - Bangladesh drinking water edition!

Sample this, from Vox, on the law of unintended consequences striking twice sequentially on two well-intentioned development interventions in Bangladesh,

In the 1970s, Western development agencies helped poor people in Bangladesh build 8.6 million tube wells — wells made by boring a steel tube into the ground — for clean drinking water. It was a large-scale development effort, and it eventually became one of the most famous stories of aid gone wrong: It turned out the wells were contaminated with arsenic.

Starting in 1999, shortly after the arsenic was discovered, researchers and Bangladesh’s government launched a massive public health campaign warning people not to use the wells after all. In development circles, the episode became a major example of how unhelpful development organizations can make things worse for the people they’re trying to help. But a new paper from the National Bureau of Economic Research says things are actually more complicated than that narrative.

Yes, there was arsenic in Bangladesh’s wells, and it may have posed a health threat. But in areas where people were encouraged to switch away from the wells, child mortality jumped by a horrifying 45 percent — and adult mortality increased too. It turns out that the alternatives to the wells, for most people in Bangladesh, were all worse — surface water contaminated with waterborne diseases, or extended storage of water in the home, which is also a major disease risk.

Is that worse than well water laced with low levels of arsenic? The paper reviews the complex, often contradictory literature around the effects of chronic low-level arsenic exposure and finds that it does increase your risk of cancer in old age. The authors conclude that risks seem to accumulate with more exposure, but the effects are still small next to the effects of unclean drinking water. That means that, in encouraging people to switch away from the wells, development agencies swapped out a fairly limited risk for a much larger risk — and people died as a result... The researchers found that one factor determined how sharply child mortality would jump when people abandoned their wells: the distance to the nearest “deep tubewell,” which provided a source of safe, clean water. Even slight increases in distance had drastic effects on child mortality.

Reinforcement of two well-known lessons.

One, there are almost always unintended effects with development interventions. The only practical response is to be vigilant in the early stages of implementation and look out for emergent problems. This makes a gradual roll-out of any new and large intervention an essential requirement.

Two, again almost always, development is about trade-offs between two competing choices, neither of which are likely to be ideal. The choice has to be based on both technical costs-benefits and social and political economy considerations.