Lead in Drinking Water Linked to Adverse Health Outcomes in Unborn Children
The nation’s battle to remove lead from drinking water may have become more urgent: A new study has found that pregnant women who consume water with high levels of lead can pass it to their unborn children.
The research, published in July in the Journal of Health Economics, is ground-breaking. Many studies have found a correlation between lead exposure and health problems, but the study authors believe theirs is the first to find an actual link between drinking lead-contaminated water and adverse health effects in fetuses.
The Newark Water Crisis
In 2016, elevated levels of lead were found in the drinking water of some public schools in Newark, New Jersey—a city that still has century-old pipes. The next year, the city’s tests found that the public water in more than 10% of Newark homes had high levels of lead.
Despite corrective efforts, such as a corrosion control process to reduce lead levels in water, the city was eventually forced to offer water filters and bottled water to tens of thousands of Newark homes.
In 2021, Newark finished its program to replace lead pipes with copper pipes. But this calamity—coming on the heels of the 2014 lead-in-water crisis in Flint, Michigan—touched off water-pipe concerns nationwide.
Tale of Two Water Treatment Plants
Newark’s water crisis also caught the interest of two economics professors, Muzhe Yang at Lehigh University and Dhaval Dave at Bentley University, who began researching the situation in 2019.
The professors saw there were two different treatment plants helping to supply Newark’s water. They used data on the home addresses of pregnant women living in Newark for their study, together with information on the boundary separating areas serviced by two different water treatment plants.
In their study, "Lead in drinking water and birth outcomes: A tale of two water treatment plants,” the professors said they found an external change in water pH levels that caused lead to leach into the drinking water of one plant's service area but not into the water of the other plant’s area.
In an exclusive interview, Prof. Yang told The Earth & I: “Residents’ exposure to lead in drinking water can be viewed as almost randomly assigned, since people decide where to live probably not based upon a water treatment plant’s service area.”
“This kind of randomization that happens in the real world—a natural experiment—helps us researchers identify a causal effect of lead exposure. It’s an effect that is due to lead exposure alone, not due to other factors.”
Their research discovered a range of evidence for negative health impacts from the water, including a 19% increase in the risk of premature birth and an 18% increase in the risk of low birth weight.
Why is Lead Dangerous?
The health impact of lead happens over time. Lead accumulates in the body through repeated exposure and builds up in the bones alongside calcium. In unborn babies, exposure is a particular problem because lead in the mother’s bones can be released as a calcium substitute to aid bone formation in the fetus. Lead in a mother’s blood can also cross the placenta, exposing the fetus to lead poisoning. Prenatal lead exposure has been associated with impaired neural development, putting children at risk for cognitive impairment later in life.
The Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) agree that there is no known safe level of lead in a child's blood.
Lead Sources and Safety Thresholds
Aging pipes have long been implicated in high levels of lead in the water supply. The EPA estimates that drinking water may account for more than 20% of total lead exposure for adults and between 40% to 60% for children.
“Old houses are more likely to have lead plumbing materials. Corrosion of these lead plumbing materials can happen when the pH level of water drops below a certain threshold.”
According to an analysis of EPA data by the Natural Resources Defense Council (NRDC), 186 million people in the United States—56% of the population—drank from water systems with lead levels exceeding 1 part per billion (ppb). This is higher than the level recommended by the American Academy of Pediatrics to protect children from lead in school water fountains.
Prof. Yang said: “I live in the Northeast of the US where there are a lot of old houses. Old houses are more likely to have lead plumbing materials. Corrosion of these lead plumbing materials can happen when the pH level of water drops below a certain threshold, that is, the water becomes more acidic than it should be. This is exactly what happened in Newark, New Jersey.”
Replacing Faulty Pipes
When it comes to lead in drinking water, the simplest and most straightforward way of dealing with the problem involves the replacement of aging infrastructure—and that’s something which has increasingly been on the agenda both at the local and federal levels in the US.
By August 2021, almost all of the lead water pipes in Newark had been replaced with copper ones, solving much of the city’s water crisis problem.
In 2019, President Biden signed the Water Infrastructure Funding Transfer Act, allowing the transfer of funds from a federal clean water fund to a state fund for lead-related projects.
More recently, in December 2021, the US Congress passed H.R.3684—otherwise known as the Infrastructure Investment and Jobs Act— that included $15 billion in funding for nationwide lead pipe replacement.
Prof. Yang welcomed these developments, and said he hopes his and others’ research will lead to more public awareness of the urgency of solving the lead pipe problem in the US water system.
“I am hopeful,” he said, “but the work needs to be done soon. High lead levels have been found in the tap water in many US cities besides Newark, such as Baltimore, Chicago, Detroit, Milwaukee, New York, Pittsburgh, and Washington, D.C.”
He warned that if something isn’t done—particularly replacing the pipes—the problems experienced in Newark could be replicated more widely.
“What happened in Newark may be the tip of an iceberg,” he said.
“There is an urgency of replacing all lead pipes in the US water system, and the work should be done as soon as possible.”
*Mark Smith is a journalist and author from the UK. He has written on subjects ranging from business and technology to world affairs, history, and popular culture for the Guardian, BBC, Telegraph, and magazines in the United States, Europe, and Southeast Asia.