For months, the city of Flint, Michigan has been dealing with a public health crisis caused by lead-contaminated water that has affected thousands of residents, particularly children. A team of researchers who tested Flint's water for lead contamination initially uncovered the problem. Officials admitted the problem when a local pediatrician revealed that the number of children with elevated blood lead levels was increasing.
Prior to April 30, 2014, the city of Flint purchased water from the City of Detroit. That water was treated with a chemical called orthophosphate, which keeps lead and copper in water pipes from leaching into drinking water. In an effort to reduce costs, Flint management decided to switch the city's water source to the Flint River. That water was not treated with orthophosphate.
Soon after the switch, Flint residents began to complain about brown, smelly water coming out of their taps as well as skin rashes, hair loss, and respiratory problems. Although state and city officials assured Flint residents that the water was safe to drink, concerns about lead poisoning emerged. In August 2015, researchers from Virginia Tech tested water samples from Flint and found that 42% had lead levels exceeding 5 parts per billion (PPB), which was suggestive of "a serious lead-in-water problem."
At about this same time, Dr. Hanna-Attisha, a Flint pediatrician, started investigating the lead issue. She compared routine blood lead test results for 1,746 children in Flint before and after April 2014. The percentage of children with elevated blood lead levels of 5 micrograms per deciliter (mcg/dL) or more had doubled since the switch to Flint River water. In certain parts of the city, the percentage had tripled.
Though Michigan officials initially challenged the pediatrician's analysis, the Michigan Department of Health and Human Services eventually confirmed Dr. Hanna-Attisha's findings. Shortly after, the city of Flint stopped using water from the Flint River and went back to obtaining water from the city of Detroit. Prior to switching back, lead levels in roughly 20% of samples exceeded 15 PPB, the threshold set by the U.S. Environmental Protection Agency (EPA) for remedial action. Since January and the switch back, less than 10% of water tests are above 15 PPB.
According to an article in Chemical and Engineering News, "Now that Flint has switched back to the Detroit water, it may take months to a year… for corrosion [of water pipes] to slow to normal levels, and for lead concentrations to drop back into an acceptable range." The lesson learned from the Flint crisis, say environmental engineers, is that continually monitoring the water supply is key, especially when switching from one source to another.
Lead is toxic, especially for children. Children exposed to lead face significantly increased risks of impaired brain development and cognitive functions, lower IQs, as well as learning and behavior problems. Lead also causes long-term harm in adults, including increased risk of high blood pressure and kidney damage.
While the Flint crisis has increased public awareness about the presence of lead in municipal water systems and home plumbing, lead-based paint also poses a threat to millions of American children. Housing built prior to 1978 may contain lead-based paint and lead-contaminated household dust. Children younger than age 6 are the most likely to be exposed because they often put their hands in their mouths, accidentally ingesting lead dust or paint chips. They can also inhale lead dust and mouth or chew lead-contaminated items.
The U.S. Centers for Disease Control and Prevention (CDC) uses a threshold level of 5 mcg/dL of blood to identify children living in environments that expose them to lead hazards. The American Academy of Pediatricians (AAP) specifically recommends blood lead testing for every Medicaid-eligible child at age 1 and again at 2 years of age. Additionally, AAP advises that healthcare providers assess all children for risk of exposure to lead and consider screening all children at 1 and 2 years of age.
There are steps people can take to prevent children's exposure to lead, such as renovating older homes safely. (For more, see this CDC Infographic.)
Measures taken during the last two decades, including amendments to the Safe Drinking Water Act and the EPA's Lead and Copper Rule, have greatly reduced exposures to lead in tap water. But as evidenced by Flint, lead can still be found in some metal water taps, interior water pipes, or pipes connecting a house to the main water pipe in the street.
You cannot see, taste, or smell lead in drinking water. The only way to know whether tap water contains lead is to have it tested. For more information, visit the CDC's webpage, Lead in Water.