Note: McKenna Coveny is a Neuroscience Student at Baylor University in Waco, Texas
Fact One: Removing Lead Linked to Large Reduction in Mental Retardation
Mental Retardation (MR) has decreased greatly as lead contamination has been reduced in the U.S. According to researcher Rick Nevin, as reported in Trends in Preschool Lead Exposure, Mental Retardation, and Scholastic Achievement: Association or Causation?, the removal of lead in the environment has corresponded to a drastic reduction In MR and a significant increase in testing scores among adolescents. Standardized test scores have been shown to be significantly higher in those with low blood lead levels (BLL) .
Fact Two: Direct Link between Elevated Lead and Lower IQ
In seminal 2005 research into the impact of lead poisoning, lead researcher Lanphear B. found, as noted in Low-Level Environmental Lead Exposure and Children’s Intellectual Function: An International Pooled Analysis in Environmental Health Perspectives, that there was a direct correlation between levels of lead in the blood and IQ. As research continued to show, even modest increases in blood-lead levels has a significant down-wade impact on IQ. This impact in also exacerbated by longer periods of elevated BLL.
Fact Three: Increased Lead Linked to Reduced Brain Volume and Increased Estimated Age
According to the authors of Decreased Brain Volume in Adults with Childhood Lead Exposure, greater lead exposure in childhood was found to be significantly associated with differences in MRI measurements of brain structure at age 45 years. The MRI results showed smaller cortical surface area, smaller hippocampal volume, lower global fractional anisotropy, and an older estimated brain age. MRI data provide concreate evidence of the negative impact of lead exposure.
Fact Four: Even Low Levels of Lead Linked to ADHD and Autism
Even low levels of lead poisoning have been found to be a significant cause of ADHD. Joel T. Nigg, et al, in Low Blood Lead Levels Associated with Clinically Diagnosed Attention-Deficit/Hyperactivity Disorder and Mediated by Weak Cognitive Control, found blood lead levels were statistically significantly higher in ADHD-combined type than in non-ADHD control children. A very significant body of research also show links between high BLL and children with autism spectrum disorder (ASD). In fact, the impairments linked to lead exposure are nearly the same as those used to quantify and diagnoses ASD.
Fact Five: Reduced Nerve and Brain Function Throughout Life
According to a paper in Neurotoxicology, by C. J. Brubaker et al, the long-term impact of childhood lead exposure on white matter integrity in young adults is significant, and damages nerve and brain interaction throughout life. This and a significant body of additional research shows that lead poisoning is not something children “out grow” but rather that the injuries are permanent.
Fact Six: Lead Impairs Cognitive Development in Children and Reduces Brain Repair
According to an article published in the journal Pediatrics, By D. Bellinger, the most significantly impaired aspect of cognitive development for children exposed to higher levels of lead were in the visual-spatial and visual-motor integration skills. According to D. A. Otto, “lead exposure affects both the retina and visual cortex of the developing and mature visual system. Low to moderate level developmental lead exposure produces selective rod deficits which can be detected with electrophysiological and behavioral techniques.”
Fact Seven: Lead Levels Linked to Violent Crime
According to Association of Prenatal and Childhood Blood Lead Concentrations with Criminal Arrests in Early Adulthood, a paper published in the Journal of PreMed in 2008, juveniles and young adults who were exposed to lead during pregnancy or development were much more likely to be arrested for violent crimes between the ages of 19 and 24. This research has been repeated again and again with similar findings. See, for example. R. Nevin’s Understanding International Crime Trends: The Legacy of Preschool Lead Exposure published in the journal Environmental Research, July 2007 104(3): 315-36.
Fact Eight: Lead Levels Linked to Anti-Social Behavior and Delinquency
In the Journal of Neurotoxicology and Teratology, researches showed that use of recreational drugs and antisocial behavior were linked to higher levels of lead in children’s blood. The highest lead levels showed the most striking impact. In fact, in a summary of the impacts of lead exposure, prolific author and Lead Poisoning expert Diana Fishbein stated, “lead toxicity has been associated with behavioral handicaps, reading disability, antisocial and hyperactive behavior, juvenile delinquency, and impaired cognition. In addition, preclinical studies suggest an association with drug addiction.”