The research team from Duke University and North Carolina Central University showed that exposure to lead contributes to lower performances on end-of-grade (EOG) reading tests among minority and low-income children.
"We found a clear dose-response pattern between lead exposure and test performance, with the effects becoming more pronounced as you move from children at the high end to the low end of the test-score curve," said lead investigator Marie Lynn Miranda, director of the Children's Environmental Health Initiative (CEHI) at Duke's Nicholas School of the Environment.
"Given the higher average lead exposure experienced by African-American children in the United States, our results show that lead does in fact explain part of the observed achievement gap that blacks, children of low socioeconomic status and other disadvantaged groups continue to exhibit in school performance in the U.S. education system, compared to middle- and upper-class whites," she added.
During the study, researchers investigated the blood-lead levels in 4th graders.
The study showed that early childhood exposure to lead, the family's poverty status and parental education all account for end-of-grade (EOG) test-score declines.
On average, exposure to lead accounts for between 7 percent and 16 percent of the decline, with the larger declines associated with higher blood-lead levels.
The study is published in the peer-reviewed journal NeuroToxicology.