Excessive lead exposure can lead to a number of problems, including kidney damage, reduced IQ and learning disabilities, growth impairments, and nerve disorders. Acute lead poisoning, caused by a sudden high exposure, may even result in seizures and death. “When pediatricians hear about lead, we freak out,” says Dr. Mona Hanna-Attisha. “We absolute1y freak out, because we know the kind of irreversible lifetime multigenerational impact.” (Rodrick, 2016)

Lead exposure & its effects on child brain development

One of the most universal and worrysome effects of lead exposure is that it causes irreversible brain damage in children. Lead is absorbed into the brain, especially by children, probably because it mimics calcium and iron, nutrients a growing brain needs. This inhibits normal growth and functioning. Studies conducted in 2008 by Kim Cecil of Cincinnati Children’s Hospital found a link between lead exposure and reduction in brain matter. They found that lead exposures through age 6 were associated with reduced tissue volumes in areas of the adult brain, especially in regions of the frontal lobe related to judgment, impulsivity and mood. (Raloff, 2009) In animal studies, maternal lead exposure during pregnancy leads to epigenetic changes in the brains of her offspring. (Hesman-Saey, 12-24-2016)

Lead exposure & lower IQ, poor school performance

Generally speaking, pediatricians say that for every 1 point blood-lead level increase, a child’s IQ can be diminished by up to 1 IQ point. In children with elevated blood-levels of lead, this can amount to a significant decrease in IQ. Many studies have linked elevated lead exposures in 2-year-olds with a diminished IQ at school age, even when peaks never exceeded the federal action level of 10 micrograms (since lowered to 5) of lead per deciliter of blood. (Raloff, 2009) “You might not notice lead effects … because the kids look okay,” states one 10-year study of affluent children in Cambridge, Massachusetts. Yet “no matter where they start out, lead exposure pushes children toward lower performance.” (Schmidt, 1999)

What’s more, unlike many toxic exposures, the effects of lead seem to be just as profound in middle childhood as they are among very young children. One study found that kids average an IQ that was 7-points lower when their age 6 blood level value was 50% greater than it was at age two, as compared to when the age 6 value was 50% less than age two. (Raloff, 2009) Another study found that from 1953 to 2003, the fall and rise of the average SAT math and verbal score has tracked the rise and fall of blood lead levels so closely that around half the change in test scores, possibly even more, were the result of variations in lead exposure. (Toppo, 2-2-2009)

The link between lead exposure & criminal behavior

Lead is a neurotoxin that damages the prefrontal region of the brain in particular, which is why it’s often linked to future criminal behavior. (Raine, 2013) The prefrontal cortex serves as the brain’s governing impulse control center, and with this impaired inhibitory control comes a higher propensity towards crime and violence.

One study found that after controlling for parental IQ, education, and income and drug use, the more lead in a child’s blood from birth through age 7, the higher their likelihood of criminality in the future, especially violent crime. (Topppo, 2008) Another study by Dr. Herbert Needleman and colleagues compared 194 delinquent youths with 146 nondelinquent peers sampled from Pittsburgh high schools. His team found that delinquent youths were 4-times as likely to have high concentrations of lead in their bones, a finding that cut across race and socioeconomic class. (Needleman et al., 2002)