Please use this identifier to cite or link to this item: https://hdl.handle.net/10419/196676 
Year of Publication: 
2019
Series/Report no.: 
IZA Discussion Papers No. 12178
Publisher: 
Institute of Labor Economics (IZA), Bonn
Abstract: 
Surface soil contamination has been long recognized as an important pathway of human lead exposure, and is now a worldwide health concern. This study estimates the causal effects of exposure to lead in topsoil on cognitive ability among 5-year-old children. We draw on individual level data from the 2000 U.S. Census, and USGS data on lead in topsoil covering a broad set of counties across the United States. Using an instrumental variable approach relying on the 1944 Interstate Highway System Plan, we find that higher lead in topsoil increases considerably the probability of 5-year-old boys experiencing cognitive difficulties such as learning, remembering, concentrating, or making decisions. Living in counties with topsoil lead concentration above the national median roughly doubles the probability of 5-year-old boys having cognitive difficulties. Nevertheless, it does not seem to affect 5-year-old girls, consistent with previous studies. Importantly, the adverse effects of lead exposure on boys are found even in counties with levels of topsoil lead concentration considered low by the guidelines from the U.S. EPA and state agencies. These findings are concerning because they suggest that legacy lead may continue to impair cognition today, both in the United States and in other countries that have considerable lead deposition in topsoil.
Subjects: 
legacy lead in soil
cognition
pre-school children
JEL: 
N52
Q53
Q56
R11
I15
I18
I25
I28
Document Type: 
Working Paper

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