Brita Filters Won’t Save Flint from Lead
Last month, President Obama travelled to Flint, Michigan to address the drinking water crisis there. He offered reassurance to the community by drinking its water, but made one important caveat — that the water must be filtered first.
“… it just confirms what we know scientifically, which is that if you’re using a filter, if you’re installing it, then Flint water at this point is drinkable”, he said.
The kind of filter the president was referring to is based on block carbon, the type found in faucet-mounted filters (pitcher filters based on granular carbon are pretty much useless for removing lead) made by companies like Brita and Pur. In some, but not all cases in Flint, this kind of filter will reduce lead to regulatory levels, and this is likely what the president meant when he said the filtered water there was “drinkable”.
The regulatory level of lead, however, does not mean “no lead”. EPA regulations dictate the concentration must be below 15 ppb, but the fact is there is no safe concentration of lead in drinking water. Lead exposure causes permanent neurological damage and long-term health effects in those who drink it. This level of filtration is much better than none at all, but it’s not good enough.
For some homes, block carbon faucet filters will reduce the lead to below the regulated limit of 15 ppb, but they are only certified to do so when the concentration of lead is equal to or less than 150 ppb at the faucet. Levels well above this have been found in homes in Flint, making the ability of these filters to reduce lead down to even 15 ppb for any individual resident uncertain.
Further uncertainty comes from the fact that this type of filter becomes completely saturated with lead and other contaminants, and must be replaced regularly, but there’s no good way for users to know when this must be done. Right now, replacement is determined by how long a filter has been in use, but this is unreliable, because the amount of contaminants coming out of residents’ taps varies from home to home.
For example, given a family of four using 12 liters a day for drinking and cooking, a Brita faucet filter on the most contaminated water tested in Flint would exhaust its capacity to remove lead in less than four days. That’s a lot less time than the approximately 32 days that the light on the filter would stay green, since the light is based on volume of flow, and not whether the filter is really removing lead or not.
The crisis in Flint is also just the most well-known example of widespread lead contamination in the U.S. Elevated lead levels have been found in New York, San Francisco, Washington DC, Newark, Chicago, and many other communities, and the more people use the proper techniques to test for lead, the more lead is found. Locating and replacing all the lead service lines and plumbing fixtures could take decades to complete. Until then, millions of Americans will continue to be exposed to the risk of elevated lead in drinking water.
What’s more, lead is only the beginning. Other heavy metals such as arsenic, as well as pharmaceuticals, pesticides, fertilizers, and industrial chemicals are routinely found in drinking water systems across the U.S. Disinfection by-products, which are known to be potent carcinogens, are present in nearly every major public drinking water system. In 2009, the Environmental Working Group released a drinking water quality report showing that New York City tap water, which has been called the “champagne of tap water,” contained six such chemicals, in addition to lead, in concentrations that exceed recommended health limits, (although they did not exceed the regulatory limits, which are higher).
These problems with our drinking water begin at the city water treatment level. The vast majority of cities use sand filtration to treat their water, a technology used by ancient Egyptians over 3000 years ago. This technology, along with chlorination, does a good job at preventing acute illnesses, such as cholera, dysentery, and typhoid fever — the kind of health risks our drinking water treatment systems were primarily designed to prevent.
But since the time of the ancient Egyptians, we’ve created and introduced tens of thousands of man-made chemicals into our environment, many of which make their way into our drinking water supplies. We’ve also learned a great deal about the harmful chemicals created when chlorine and other disinfectants interact with the decayed plant matter naturally found in water, which are referred to broadly as disinfection byproducts. Less than 15 years ago, concern over chemical contamination in our food supply drove the widespread and growing demand for an organic standard for our food. Until now, no similar movement has occurred to create an organic standard for our drinking water. It should.
The crisis in Flint has revealed the fact that we can’t take clean water for granted. It also presents an opportunity to ask ourselves what “good enough” means for our drinking water. At a minimum, it should be water free of lead and other heavy metals; viruses, bacteria, and other pathogens; pesticides, herbicides, and fertilizers; algal toxins; disinfection byproducts; and industrial chemicals. Our water today does not meet this standard. We should demand that it does, and start to act to ensure that we achieve it.
The way the government determines safe limits of contaminants in our drinking water today is based on a compromise between water quality and what is seen as economically and technically feasible, and not on a water purity standard like the one above. It is based on a general conservatism in water treatment operations, which favors using sand filtration because it’s a “mature technology”, that is good enough to meet the regulatory limits, and is relatively cheap to do. This is a kind of regulatory — economic feedback loop in which nothing changes unless there is a sufficient popular will to do so.
Today, there are better technologies for drinking water treatment, such as nanofiltration and advanced oxidation, which are proven and also “mature,” but reach a much higher standard of water purity than sand filtration. Recently, there’s been exciting progress on new filters, such as those made with carbon nanotubes or graphene, that will dramatically lower the cost and improve the performance of these water treatment methods, while making them compact enough to use in the home. These would be vastly superior to the block carbon filters now being used in Flint.
The quality of our drinking water today is unacceptable. We should do better, by investing in our public infrastructure to remove lead pipes and fixtures, and treat water to a higher standard than sand filtration can provide. And we should use better filters in our homes to ensure that the water we drink is pure. The problem in Flint is more than an isolated crisis, it’s a symptom of a much larger problem that we all face and should solve together by saying that what has been “good enough” isn’t anymore.