The Legacy Lead Deposition in Soils and Its Impact on Cognitive Function in Preschool-Aged Children in the United States

50 Pages Posted: 9 Mar 2019

See all articles by Karen Clay

Karen Clay

Carnegie Mellon University - H. John Heinz III School of Public Policy and Management; National Bureau of Economic Research (NBER)

Margarita Portnykh

Carnegie Mellon University

Edson Severnini

Carnegie Mellon University

Multiple version iconThere are 2 versions of this paper

Date Written: February 18, 2019

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.

Keywords: lead, soil, cognitive function

JEL Classification: Q53, I18, I24

Suggested Citation

Clay, Karen B. and Portnykh, Margarita and Severnini, Edson, The Legacy Lead Deposition in Soils and Its Impact on Cognitive Function in Preschool-Aged Children in the United States (February 18, 2019). Available at SSRN: https://ssrn.com/abstract=3337156 or http://dx.doi.org/10.2139/ssrn.3337156

Karen B. Clay (Contact Author)

Carnegie Mellon University - H. John Heinz III School of Public Policy and Management ( email )

Pittsburgh, PA 15213-3890
United States

National Bureau of Economic Research (NBER) ( email )

1050 Massachusetts Avenue
Cambridge, MA 02138
United States

Margarita Portnykh

Carnegie Mellon University ( email )

Pittsburgh, PA 15213-3890
United States

Edson Severnini

Carnegie Mellon University

Pittsburgh, PA 15213-3890
United States

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