21 January 2016. A lead poisoning episode has unfolded right in front of us. About 100 km from Detroit, the City council of Flint, Michigan, decided to switch its water supply from Detroit’s Lake Huron water to the local Flint River. That happened in April, 2014, and the aim was to contain costs in a time of financial distress. Flint River was considered only a temporary solution, though, and a longer-term goal was to connect to another pipeline from Lake Huron. Soon after the switch, residents began to complain about the color and taste of the community water. Then analyses showed that the city’s drinking water was severely contaminated with lead, with some tap water samples showing such huge amounts that they could cause clinical poisoning. Indeed, the local health center began to report severe elevations of children’s lead concentrations in blood.
Last October, the water supply was finally switched back to Detroit, and a corrosion inhibitor (orthophosphate) was added to the water. By now, it seems that the immediate problem has been resolved, at great costs. And as long as water pipes made of lead remain in place, the problem can emerge if the water quality changes again.
Flint and its 100,000 inhabitants still suffer from the economic depression following the closure of local automobile factories, and the city was in a state of financial emergency until last year. But public health decision-making during an economic recession may result in short-term and dangerous decisions. Now, the City officials, the Governor, Environmental Protection Agency experts, and others are arguing who is to blame for allowing the lead contamination to happen and to continue for well over a year. By now, the situation has turned into a national scandal.
It should not have happened. The Flint River water is highly corrosive and therefore causes leaching of lead into the drinking water from existing pipes. It could have been predicted and it could have been prevented. We are dealing with an ancient problem (see “Only one chance”, Chapter 3). Since the Roman period, the malleable and inexpensive metal has found use for multiple purposes, in particular for water pipes (we still call the “plumber” to fix the drain, using a term that originates from the Latin plumbum word for lead). But this application is not without risks, as lead can be dissolved by weak acids. Already during the first century BC, Vitruvius warned that toxic amounts of lead could be released into drinking water. It became clear that soft water – with low calcium concentrations – resulted in release of lead from the water conduits.
Providing access to pure community water was a major public health victory. Epidemics of cholera and other water-borne diseases in the late 1800s called for action, and piped drinking water became an instant success that resulted in sharp declines in mortality from diarrhea. However, lead was the favorite material for water conduits, and University of Pittsburgh historian Werner Troesken has documented how the lead pipes caused an environmental disaster that started to unfold more than 100 years ago. The Lead Industries Association kept insisting that lead was a safe and cost-effective material for water pipes. In the end, plumbing codes were changed only a few decades ago to require water pipes made of materials other than lead. So in Flint and most US communities, service lines, distribution lines, and household water pipes are often made of lead.
Flint is by far not the first community where lead poisoning has emerged as a “new” problem. Fifteen years ago, Washington, DC, changed the disinfection chemical used for the municipal water supply from chlorine to chloramine. This switch made the water more aggressive and caused lead to leach from the water pipes. In this case, the problem was not recognized and corrected until three years later. In the meantime, the toxic metal was building up in the residents and in children’s brains. In Durham, NC, a similar problem occurred when a change in water treatment from alum to ferric chloride caused increased corrosion, and likewise in Maine, where the corrosion was due to a new anion exchange system. In all of these cases, the problems could have been foreseen, but decisions on water treatment were primarily made from considerations of cost and feasibility. The hazards from lead pipes were ignored to the detriment of public health. Exchanging the pipes can be very costly, especially if their locations are no longer known, so adding lime and other corrosion inhibitors to the community water has been most frequently used as a remedy. That means that a potential problem remains and could emerge at some future time when the water quality changes again.
The problem in Flint is sad and also infuriating, because lead is likely the most extensively studied pollutant. First, the conditions that trigger lead release from water pipes are well known. Second, thousands of investigations have shown that lead is particularly toxic to the brain, especially in children. Increased exposure to this metal is known to cause an increased risk of mental retardation, ADHD and other serious ailments. Lead exposure also causes less marked mental deficits resulting in poor school performance and decreased educational achievements. This is the prime example of chemical brain drain. When calculated from the loss of lifetime income, the U.S. costs from lead exposure reach large billion dollar amounts per year. In Flint, the costs will not be apparent in the short term. But the brains of the Flint children have suffered from the lead exposure, and they will carry the burden the rest of their lives.