High levels of lead in topsoil boosts the likelihood that 5-year-old boys will have cognitive difficulties, .
Researcher Edson Severnini of Carnegie Mellon University and his co-authors examined data from the U.S. Geological Survey on lead in topsoil in the nation鈥檚 252 largest counties. They found that living in counties where the ground contains lead levels above the national median doubles the probability that boys will have problems remembering, concentrating, and making decisions at age 5. No effect was found for girls the same age.
The study was published last month in the journal Economics and Human Biology.
