The Threat of Lead

Widespread human exposure to lead in Flint, Michigan, has affected thousands of people, many of them children, and public officials there are grappling with a response to a growing health crisis. Lead exposure poses a serious health risk to people who ingest the heavy metal. The threat is pronounced in older structures that have lead-based paints and where lead was used in the plumbing that brings drinking water into homes and buildings.

A panel of Yale School of Public Health (YSPH) experts in the Department of Environmental Health Sciences—Vasilis Vasiliou, Ph.D., professor and department chair; Ying Chen, M.D., Ph.D., research scientist; Nicole Deziel, Ph.D., assistant professor; and Gary Ginsburg, Ph.D., lecturer—responds to a series of questions about the dangers of lead exposure and what people can do to safeguard themselves and their families. Here are their responses:

How does lead get into the water people drink?

YSPH: The main source of lead in drinking water is through the corrosion of lead-containing materials in the water distribution system and home plumbing pipes and fixtures. Lead was banned from plumbing materials in 1986, but lead can still be found in older homes and neighborhoods in service pipes, metal water taps, interior water pipes, or solder used to join copper piping. Drinking water treatment plants are required to add anti-corrosive agents to the water to minimize contamination with lead.

Does lead have a taste? Can people tell that something is different about their water?

YSPH: You cannot see, smell or taste lead in drinking water; however, a corrosion problem may turn the drinking water a rust color. The only way to find out if lead is present is to have your water tested. You may suspect lead in your water if your home was built before 1986, or if your water turns a rust color. Sudden changes in color or odor could indicate other public health concerns. If this occurs, do not use the water, and report the changes to your water utility if you are on a public water supply or your local health agency if you have your own well.

Explain how safe lead levels are calculated? What is a safe lead level for an adult? A child six or under?

YSPH: There is scientific consensus that there is no “safe” level of lead exposure; exposure to lead at any level could be harmful. However, “action levels” have been established for drinking water and blood. If the lead exceeds these levels, steps must be taken to reduce exposure. These levels are designed to protect young children (e.g. six and under), who are particularly sensitive to the effects of lead, such that even the lowest doses can impair their intellectual and behavioral development. The U.S. Environmental Protection Agency (EPA) sets an action level of 15 parts per billion of lead in public water supplies. The Centers for Disease Control and Prevention defines a blood lead level of 5 micrograms per deciliter (µg/dL) as “elevated” to identify children for follow-up actions.

What are the physical and mental symptoms of too much lead exposure?

YSPH: Lead exposure interferes with a variety of body functions. However, children with lead poisoning may not show any signs of being sick. The higher the amount of lead in the body, the more severe the symptoms are. In children, symptoms can appear as irritability, learning disability, lack of energy, loss of appetite, abdominal pain, vomiting or nausea. In adults, the effects of lead include increased blood pressure, kidney problems, and effects on the brain. The symptoms can manifest as behavioral and personality changes, memory loss, muscle weakness and pain, headaches. In pregnant women, high levels of lead can cause miscarriage, premature birth and low birth weight, and minor malformations.

Over the long run, what happens if lead exposure goes untreated?

YSPH: Of paramount concern is that lead exposure can cause irreversible damage to a child’s brain function. Effects may include lower IQ, attention deficit-hyperactivity disorder, and behavioral problems. These effects have lasting effects on children’s growth and development and may limit their ability to reach their full potential as adults. Long-term exposure in adults is linked to increased risk of kidney problems, high blood pressure, heart disease, and fertility problems. In cases of severe untreated lead poisoning, effects can include persistent vomiting, encephalopathy (a brain malfunction with symptoms ranging from mild changes in mental status to severe manifestations, including dementia), lethargy, delirium, convulsions, coma and ultimately death.

Lead “bio-accumulates” in the body, meaning it stays in the body and builds up over time. Does that mean the body cannot purge itself of this contaminant?

YSPH: If lead gets into our bodies, it is stored in blood, bones, and tissues. When the source of lead exposure is removed, the body gradually and naturally eliminates the lead. The elimination half-life of lead in adults (i.e., the time it takes for the blood concentration to decrease by half) is estimated to be 1 month, whereas in children it may be as high as 10 months. Lead stored in bones may be released into the bloodstream during pregnancy, lactation, menopause, physiologic stress, hyperthyroidism, kidney disease, fractures, and advanced age.

Can someone with high lead levels be treated?

YSPH: Yes, lead poisoning is treatable. Treatment for blood levels below 40 µg/dl is to simply remove the exposure. Above that, chelation therapy, which uses chemicals to bind with lead so the body can get rid of it naturally, may be considered based upon the clinical symptoms and exposure characteristics.

There is scientific consensus that there is no “safe” level of lead exposure; exposure to lead at any level could be harmful.

Besides drinking water, what other ways might somebody get exposed to dangerous levels of lead?

YSPH: The most significant source of lead exposure in children in the United States is lead-based paint in homes built before 1978. Other sources include workplaces that involve lead, contaminated food, soil and air, lead containing household and commercial products, certain hobbies (e.g., making pottery or fishing lures) and some folk remedies.

What can people do to protect themselves from this potential health threat?

YSPH: Ensuring that your home is lead-free can prevent lead poisoning. Several actions can be taken to help reduce the risk of lead exposure.

  • Be aware of lead-containing materials in your plumbing system. You can test the lead levels in your tap water using commercially available kits. You can purchase a filter to remove the lead from tap water. Also, you can run cold water for a few minutes before using the water. Alternatively, lead plumbing or fixtures could be replaced.
  • Ensure lead paint is intact and not flaking or peeling.
  • Wash your children’s hands and toys often and keep dusty surfaces clean.
  • Ensure a diet rich in antioxidants found in fresh vegetables and fruits that will help mitigate lead toxicity.
  • Have your children tested for lead exposure, particularly when they're younger than 3 years old.

Is tainted water the biggest single source of lead exposure for Americans?

YSPH: No. Lead-based paint in older buildings remains the most significant source of lead exposure in the United States.

Besides lead poisoning, what other health threats are posed by impure water?

YSPH: Water quality issues can result from various sources of contamination, including naturally occurring chemicals and minerals (e.g., arsenic, radon, uranium), land use practices (e.g., fertilizers and pesticides), manufacturing processes, and wastewater releases (e.g., bacteria). Presence of these contaminants in the drinking water can cause human diseases ranging from gastrointestinal illness to neurological disorders.

The news about lead-tainted water in Flint, Michigan, is alarming; could something like this potentially happen here (in Connecticut)?

YSPH: In the U.S., including the Northeast, we have an aging water distribution system and many people have homes with lead plumbing. However, Connecticut adjusts the water chemistry to minimize the amount of corrosion that can occur. Connecticut has some of the most stringent potable drinking water regulations in the United States. Potable public drinking water supplies are strictly regulated by the Connecticut Department of Public Health, and drinking water supply companies are held to the highest standards with respect to water testing reports, professional certifications and regulatory audits. In addition, all Connecticut drinking water is sourced from well-protected reservoirs and deep-well water supplies. In Flint, Michigan, the Flint River was used for the drinking water source. In contrast, in Connecticut, rivers, streams and other water supplies are not allowed for potable use by the Connecticut drinking water regulations.

However, here in Connecticut we also use private wells for drinking water, which may also have corrosion issues. Private wells are not regulated by the EPA or the state health department; it is up to individual residents to test their own well water. All the actions recommended for the community water supply (e.g., testing, filtering, running cold water) also apply to well water.

Even with strict protections in place, problems could occur. If you have any concerns about the quality of your water, you can contact your water supplier or health agencies or refer to the resources provided below.

Where can people go for more information on water contaminated with lead and other substances?

YSPH: The following resources can provide more information:

To learn more about the work of the Department of Environmental Health Sciences at the Yale School of Public Health, visit

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This article was submitted by Denise Meyer on February 2, 2016.

Related People

Ying Chen

Research Scientist in Epidemiology (Environmental Health Sciences)

Nicole Cardello Deziel

Assistant Professor of Epidemiology (Environmental Health Sciences)

Gary Lee Ginsberg

Lecturer in Epidemiology (Environmental Health)

Vasilis Vasiliou

Department Chair and Professor of Epidemiology (Environmental Health Sciences) and of Ophthalmology and Visual Science