Nationwide tests find lead in more than half of U.S. children

HANNAH NORTHEY | 09/29/2021 01:29 PM EDT

This 2016 file photo shows signs around the West Calumet Housing Complex in East Chicago, Ind. The mayor ordered the evacuation of the 40-year-old public housing complex because of severe lead contamination.John J. Watkins/The Times via AP, File

GREENWIRE | A first-of-its-kind national study found more than half the children tested had detectable levels of lead in their blood, a scourge researchers say is tied to contaminated paint, water pipes and soil in poverty-stricken neighborhoods.

An investigation published in the medical journal JAMA Pediatrics earlier this week revealed the detectable lead levels in more than half of the 1 million children under 6 years old who received blood tests in recent years from Quest Diagnostics, one of the largest clinical laboratories operating in the U.S.

Detectable levels of lead were significantly increased in children with public insurance and those living in communities with pre-1950s housing and high poverty rates.

The study also found trends based on ZIP codes and race, with almost 58 percent of children in predominantly Black neighborhoods and 56 percent of children in predominantly Hispanic areas showing detectable lead levels, compared with 49 percent of children in white neighborhoods. But authors also found the associations between lead exposure and elevated levels in children living in ZIP codes with predominantly Black or Hispanic and Latino neighborhoods were “not consistent” and more research is needed.

“This study is one of the first I’m aware of that really looks [nationally at] detectable blood levels” and neighborhood factors such as poverty, said Marissa Hauptman, associate director of the Pediatric Environmental Health Center at the Boston Children’s Hospital, who co-authored the study.

Quest Diagnostics conducted the testing from Oct. 1, 2018, through Feb. 29, 2020, during which time the lab began reporting results with a detection threshold of 1 microgram of lead per deciliter of blood. According to the JAMA article, the month of February 2020 was chosen to eliminate the potential effects tied to the ongoing COVID-19 pandemic.

Researchers then used mapping techniques and analyses to show the association between where a child lives and the risk of lead exposure. The insight is critical given that lead is a toxin that can have adverse health effects particularly in pregnant people, nursing mothers and children under age 6 whose bodies are still developing and growing rapidly. Even at low levels, lead exposure is shown to affect IQ, ability to pay attention and academic achievement, according to the Centers for Disease Control and Prevention, and exposure cannot be corrected.

The CDC currently identifies the “blood lead level of concern” as 5 micrograms of lead per deciliter of blood, which the agency says is higher than most children’s levels. The CDC says that value is based on the nation's population of children under 5 who are in the highest 2.5 percent of kids when tested for lead in their blood.

Hauptman said the findings demonstrate that the U.S. is still living with the effects of legacy lead and children are being exposed despite “tremendous progress” made in past decades toward eliminating lead from products like fuel; paint; and service lines carrying water to homes, schools and businesses.

While the study did not analyze the sources of exposure, Hauptman said a large body of research and public policy work shows children are primarily exposed to lead through paint, contaminated soil and drinking water.

According to the article, houses built before the 1950s were specifically analyzed because although the production of lead-based paint was banned nationally in 1978, some cities had enacted legislation to bar the material as early as the 1950s. Overall, paint produced after the 1950s tended to have lower levels of lead, researchers said.

Going forward, Hauptman said researchers need to focus on how to prevent lead from making its way into housing stock, fuel and water to protect children. The study also called for more analysis to understand the relationship between exposure in children and race.