Drinking Water (16 page)
Venice is a city of visual delights, from the sleek black gondolas and graceful bridges to the ornate churches and balconies astride the canal waters. Yet perhaps the most marvelous accomplishment of all, the source of clean water during
La Serenissima’s
years of power, lies unseen beneath the plazas and tourists’ steps.
A
RSENIC HAS LONG BEEN THE MURDERER’S POISON OF CHOICE
. Clear when dissolved, odorless, tasteless, it is almost too easy to slip some of the deadly white powder into an unsuspecting person’s food or drink. In cases of quick poisoning, the victim feels cold, clammy, and dizzy with painful stomach cramps. Death follows shortly after. Arsenic’s effectiveness and ease in dispatching people was the driver behind the classic play and movie
Arsenic and Old Lace
, where two well-meaning though misguided women eased the passage to the hereafter for lonely widowers enjoying their cookies and poisoned elderberry wine. The most famous historic case of arsenic poisoning may have involved Napoleon, who died on the distant island of St. Helena after his grand attempts of conquering Europe had failed. While the diagnosis at the time of the emperor’s death was stomach cancer, modern analysis of his hair suggests arsenic poisoning.
Arsenic is not only lethal when delivered intentionally, however. The compound also occurs naturally in the common mineral arsenopyrite. When these rocks erode, arsenic is released into the soil and groundwater. Even the most reckless person knows that drinking arsenic is a bad idea. Yet, just a decade ago, controversies over how much arsenic people should drink in their water led to public furors in both the world’s wealthiest and poorest countries, with very different results.
One of the most densely populated and impoverished countries in the world, Bangladesh sits in the delta of the Ganges and Brahmaputra rivers. Access to freshwater is not a problem—quite the contrary,
as the country often suffers from seasonal flooding. Unfortunately, these rivers are heavily polluted as they move downstream and are thus unfit for drinking. Traditionally, Bangladeshis have relied on surface waters from ponds and shallow wells for their domestic water use. Pollution from inadequate (often nonexistent) sewage systems, however, has made high death rates from cholera and diarrhea commonplace, particularly among the young. Seeking to remedy this public health problem, the World Bank and the United Nations Children’s Fund (UNICEF) agreed to fund a nationwide program. The ambitious goal was to shift domestic sources from surface water to the country’s plentiful groundwater. Groundwater is generally safer than surface sources such as lakes or rivers because the soil filters bacteria and pollution as water percolates down into the aquifer. Literally millions of tubewells—shallow pipes operated by steel hand pumps—were eventually sunk throughout the countryside.
On the surface, this seemed a poster child for what development aid should be all about, providing simple, inexpensive, and effective technology to overcome a terrible public health challenge. Victory was quickly and confidently declared. As researchers later described:
A tubewell became a prized possession: it lessened the burden on women, who no longer had to trek long distances with their pots and pails; it reduced the dependence on better-off neighbors; and most important, it provided pathogen-free water to drink. By the early 1990s ninety-five percent of Bangladesh’s population had access to “safe” water, virtually all of it through the country’s more than 10 million tubewells—a rare success story in the otherwise impoverished nation.
While the aid groups were congratulating themselves, however, tests of the groundwater revealed a tragedy unfolding. Many of the plentiful freshwater aquifers were located in soils containing arsenic. It had not occurred to any of the engineers to test for naturally occurring arsenic when the wells had been drilled, but it was surely there. Laid down in geologic strata over millions of years, the undetected arsenic had dissolved into the groundwater and was now being pumped up for drinking and domestic use.
The largest public drinking water initiative in the history of Bangladesh had monstrously transformed into the worst case of mass poisoning in the world. Wells in fifty-nine of sixty-four of the country’s regions exceed the World Health Organization’s guidelines for arsenic in drinking water, and roughly 10 percent of the wells contain more than six times that amount. No one knows just how many people are at risk of arsenic poisoning, but the estimate in 2010 was well over seventy million.
Acute arsenic poisoning can kill within a few hours. Much more common, however, and unlike most waterborne diseases, chronic arsenic poisoning can remain in hiding for up to ten years before revealing itself. The initial symptoms include black spots on the upper body, bronchitis, and loss of sensation. In serious cases, this gives way to swollen legs, cracking palms and soles, and renal malfunction. If the victim survives the likely threats of gangrene and kidney failure, cancer follows. A number of field projects tested wells, painting those with high arsenic levels red and those with low levels green, and this has had some effect. But most wells remain untested, and many people continue to draw their water from red wells.
While Bangladesh and the international development community struggled to respond to their self-inflicted epidemic, halfway across the world, in the world’s wealthiest country, concerns over arsenic in drinking water were front page news, as well.
The United States has had an arsenic standard of fifty parts per billion since 1942. Over the past few decades, however, studies in Argentina, Taiwan, and Chile have suggested harmful effects from drinking water with much lower arsenic concentrations. The Environmental Protection Agency and National Research Council started examining the issue and modeling the likely impacts from drinking water with concentrations below 50 parts per billion.
In 2000, shortly before President Clinton left office, his administration proposed a new regulation lowering the legal limit to five parts per billion, comparable to one drop of arsenic in fifty drums of water. Faced with strong complaints by both water system managers and industry over the high costs of compliance and weak scientific case for a five-parts-per-billion standard, the administration
doubled the limit to ten parts per billion, the same as that recommended by the World Health Organization. While the new standard would apply to all 54,000 of the country’s community water systems, it was estimated that only a small number of water sources, mostly in the West, would be affected. Specifically, regulators estimated that about 5 percent of the systems would need to take action, affecting the water for roughly eleven million people, plus an additional two million people not on community water systems. The rule was scheduled to go into effect in March 2001, two months after George W. Bush took his oath of office.
One of the very first acts of the new Bush administration’s EPA, however, was to suspend implementation of the new arsenic drinking water regulations pending further study. The public response was loud and powerful, creating one of the administration’s very first controversies. Even the staunchly conservative
Wall Street Journal
thundered, “You may have voted for him, but you didn’t vote for this in your water.” Representative David Bonior was even more caustic. “If there is one thing we all seem to agree on it is that we do not want arsenic in our drinking water. It is an extremely potent human carcinogen.” Stating the obvious, he continued, “It is this simple: arsenic is a killer.”
So why did the Bush administration take such a seemingly foolish action? The policy choice was whether to keep the current standard of fifty parts per billion or tighten it to ten parts per billion. It was well understood that the standard would impose significant costs, particularly on small communities. The question was whether it was worth the cost. One might assume it clearly was worth it, given the dangers from arsenic. No one wants to drink poison, even in small amounts, when they turn on their tap.
Is arsenic in the water safe to drink at any level? Perhaps surprisingly, neither Americans nor Bangladeshis have been able to answer that question, but for very different reasons. For the Bangladeshis, the more relevant question is which water source is
less
unsafe to drink? As one researcher described, “It took about twenty years to move everyone from surface water to ground water and then in the 1990s we are suddenly telling people the groundwater can kill you.” While some have suggested that people be encouraged
to go back to surface water, this poses real problems as well. After all, the harm from microbial diseases is why they switched to groundwater in the first place.
In a recent study, 29 percent of the water users stopped taking their water from wells once they were told the water had high levels of arsenic. But that still leaves more than half of Bangladesh’s population exposed. As the researchers concluded, despite identifying many of the wells as either safe (green) or unsafe (red), “Even with complete identification of contaminated wells, rural households are left facing a dilemma: Use river or pond water and face waterborne disease, or use groundwater, if it is still within reach of hand pumps, and face slow poisoning from arsenic. Families without alternative sources of drinking water continue to use arsenic-contaminated tubewell water, and the response to poisoning has been slow and incomplete.” These same researchers found that where a green tubewell required a long walk, many families decided to rely on the nearby polluted water.
In deciding which water is safer to drink, villagers are surely undertaking some sort of personal risk assessment. On the one side are the ease and modernity of using tubewell water, which they are now being told may be dangerous to drink. On the other is surface water, which they know can lead to cholera and diarrhea. Waterborne diseases in surface water strike quickly, making the connection between disease and water easy to draw. Arsenic is a slow killer, unseen until it strikes years later.
This type of decision is known as a “risk-risk” choice. Each option comes with costs. As the saying goes, out of the frying pan and into the fire. Balancing the trade-offs in this risk-risk dilemma is complex, and most certainly not a purely technical question. Time spent going to a more distant green tubewell rather than a closer red tubewell can impose its own costs in lost time. And which water you drink can also be a status statement. As one field worker has described, “In conversations with villagers, we realized that although they want arsenic-free water, they do not want to feel that they are going back in time to methods they once discarded. Tubewells had fitted nicely with their forward-looking aspirations.”
Sometimes the devil you know in surface waters is worse than the one you do not know in groundwater. In areas of the country racked with poverty and a low life expectancy, how should people balance uncertain short- and long-term health threats against the convenience, sense of self-worth, and time saved of nearby tubewell water? The situation remains tragic precisely because there are no easy solutions.
And what of arsenic in the United States? Threats facing Americans are very different than those in Bangladesh. Drinking water in the house is never more than a few feet away. Representative Bonior spoke for a lot of people when he said, “It is this simple: arsenic is a killer.” Unfortunately, it really isn’t this simple.
While everyone wants safe water, the problem is that no one knows just how much more dangerous it is to drink water containing ten parts per billion of arsenic rather than fifty parts per billion. To put this in a different context, the choice is roughly between ten versus fifty pinches of salt in ten tons of potato chips, or ten versus fifty seconds over thirty-two years. To the naked eye, it’s not a big difference.
We all know that drinking arsenic isn’t good for you. That explains the widespread criticism of the Bush decision to keep the fifty-parts-per-billion standard in place. But what if there isn’t much difference to the public health provided by the more stringent standard, and the projected $200 million for compliance costs could be spent on other investments, perhaps additional capacity in the water treatment plant, instead?
The science wasn’t very helpful. In the EPA’s analysis for the new regulation, the calculated benefits were extremely uncertain, with estimates ranging from six lives saved through the new standards to one hundred and twelve. Spending $10 million to save a life may seem a wise use of public funds. You may feel differently if the cost were closer to $1 billion per life. Cass Sunstein, a professor at Harvard Law School and the Obama administration’s chief reviewer of agency regulations, looked carefully at the history of the arsenic regulation and concluded, somewhat with his hands in the air, that “EPA could make many reasonable decisions here,
and in the range below 50 parts per billion and above 5 parts per billion, there is no obviously correct choice.”
Nor is this dilemma limited to arsenic. One could tell a similar story about a wide range of compounds in drinking water. Consider, for example, the case of chlorine, the single largest contributor to safe drinking water in the history of public health. Perhaps surprisingly, the debate over chlorination continues today. A class of compounds known as trihalomethanes can be produced as a by-product of chlorination in the presence of water containing organic materials such as humic acids. Trihalomethanes, most notably chloroform, are carcinogens. While there is uncertainty over the data, they suggest a connection between chlorinated water and bladder, colon, and rectal cancer. Such controversies over chlorination pose risk-risk dilemmas. Earnest efforts to make our water safer may expose us to a new class of harms. And it is not just protection from microbial disease versus heightened risk of cancer. Other trade-offs pose disease versus mortality, younger versus older victims, and well-understood threats versus significant uncertainty. Experts feel that the benefits from chlorination outweigh the harms from increased risk of cancer. They are probably right, but there are significant unknowns in this assessment.
