The Effect of Low Levels of Blood Lead on Children's Test Scores.

The recent discovery of high levels of lead in the drinking water in Flint, Michigan, and in several urban school districts has focused public attention on the potential harms of blood lead, particularly for children’s development. While child blood lead levels (BLLs) have declined dramatically over the past several decades, estimates suggest that there are still a half a million preschoolaged children in the U.S. with elevated blood lead levels. Although there is strong epidemiological evidence linking early lead exposure to negative child outcomes, much of this evidence relies on correlations. As children with high BLLs are more likely to come from minority groups, be poor, live in single-parent homes, and have less-educated mothers, it is difficult to distinguish the effect of elevated BLLs from these other potentially confounding factors. In addition, much of the exist-