Even Low Levels Of Lead Impact Children's Test Scores, New Study Finds

Lead in paint, pipes and dirt still plagues our cities and towns even since the government began regulating its use in the 1970s and outright banned lead paints in 1978. And a new study from the National Bureau of Economic Research, a non-profit research organization, confirms what many have long suspected: Even very low levels of lead exposure can cause a measurable decrease in students' academic achievement.

Of course, we've known for a long time that lead exposure is dangerous. Acute lead poisoning occurs when someone ingests large amounts of lead, which can lead to vomiting, convulsions or coma, explained Eric Potash, a post-doctoral researcher at the University of Chicago's Center for Data Science and Public Policy who was not involved in the new study.

"Thankfully, those levels of exposure are extremely rare," he said.

But the Centers for Disease Control and Prevention counts children as having a "elevated blood lead level" if the amount of lead in their blood is measured at 5 micrograms per deciliter. This is a very small amount, but as the new study shows, even smaller levels can have deleterious effects.

"Today the public health community is most concerned with chronic exposure to 'low' levels of lead during childhood," said Potash. "Unlike acute exposure, the effects are often not immediate, so epidemiologists have to do careful long-term studies to understand the effects of chronic lead exposure."

Researchers Anna Aizer, Peter Simon and Patrick Vivier from Brown University and Janet Currie from Princeton University examined a lead removal program in Rhode Island to evaluate the project's effects. The state's policies pressured landlords to update housing, particularly in the oldest city centers, to remove potential lead contaminants.

The effects of lead exposure are somewhat tricky to measure, because it's obviously not permissible to run experimental trials by giving different children certain levels of lead exposure. And since poorer families, like those living in older urban neighborhoods, tend to be those most likely to be exposed to lead, it's difficult to differentiate the effects of poverty from the effects of lead exposure. By looking at a program that targeted low-income and minority neighborhoods, as Rhode Island's program did, it allowed the researchers to hone in on the effects of lead.

The findings are pretty stark: Reducing the amount of lead in a child's blood by just one microgram per deciliter is associated with a 3.1 percent decrease in the chance of falling into the "substantially below proficient" category on reading tests and a 2.1 percent reduction in the chance of receiving that ranking on math tests.

Perhaps even more strikingly, the authors hold that the lead reduction program they studied contributed to a substantial portion of the decrease in the achievement gap between white students and black students observed since implementation.

Since the CDC has considered 5 micrograms of lead per deciliter of blood the threshold for considering a child's levels "elevated" since 2012, with a higher threshold before that, much of this impact could easily have been ignored.

Given the impacts of even small amounts of lead, and the fact that even the CDC says that no amount of lead exposure is safe, why haven't we undertaken more measures like Rhode Island's?

"The basic reason is that removing lead costs money, and not everyone wants to spend money," said Potash.

Replacing lead paint or lead piping, for example, can be quite expensive. Potash also points out that the conditions that led to the recent lead crisis in Flint, Michigan, came out of budgetary concerns and public safety shortcuts.

However, with a growing research base emphasizing the costs of lead exposure at every level, the calls for serious lead abatement programs will likely grow louder. Even though a few points on reading or math tests may not sound that important, the cumulative effect of millions of children being exposed to even low levels of lead may in the end be very costly itself.

What should you do if you're worried about your child being exposed to lead? First, know how old your house is; homes built after 1978 should not have lead paint in them, since it was banned that year.

If you think your child has been exposed, the CDC recommends speaking with your doctor. They should be able to test your child's levels and help you determine what, if anything, is exposing your child to lead.

Photo credit: Moe Alves via Flickr