It is hard to grasp just how poisonous lead is to young children. An average grain of salt weighs approximately 100 micrograms. Dissolve that in 2 liters of water and you have a concentration of 5 micrograms per deciliter. What do these miniscule amounts of lead do to a young child? Effects linked to low-level lead exposure in children include reductions in IQ, learning disabilities, and ADHD. Ralph Spezio, a Rochester NY principal, found that all of the children in his school’s special education programs had histories of elevated lead exposures. The brain damage caused by lead is permanent, and the only way to prevent harm is to prevent exposure.
Recent research highlights some long-term effects of this brain damage. Several studies show a strong correlation – for many cities, across many countries – between lead exposures and later criminal behavior. The figure below comes from a recent study by Howard Mielke and Sammy Zahran. It shows a striking correlation between atmospheric lead emissions (the blue line, and left axis) – primarily from automobile emissions of leaded fuels – and criminal behavior (the red line, and right axis) 22 years later. In this case the criminal behavior measured was the rate of aggravated assaults reported by New Orleans police to the FBI. Other measures (murder rates, even teen pregnancy rates) also show strong correlations with previous lead exposure, reflecting the long-lasting damage cause by lead to the brain’s decision-making capabilities. Correlation does not necessarily indicate a cause and effect relationship, but numerous studies with animals and humans confirm that brain damage results from lead exposure, and recent MRI studies of the brains of lead-exposed individuals demonstrate that childhood lead exposures result in changes that persist into adulthood.
While lead exposures from leaded gasoline are no longer a problem in the US, older housing built before lead paint was banned in 1978 remains a source of serious lead exposure to children. This is likely where Freddie Gray’s exposure came from. It is not just Baltimore and other inner cities where this is a problem. Ashland and Ashland County has a significant proportion of older housing, and areas where children are at serious risk of having elevated lead levels. The Ohio Department of Health reports that one of the highest risk areas in the county is the area of older housing immediately surrounding the University:
|Peeling paint on an Ashland garage contains more than 300,000 parts per million of lead.|
The connections between lead exposures and brain damage that impairs the ability of individuals to make decisions later in life are sobering. Working to eliminate lead exposures to children is not only important to helping them achieve their full potential, but can also contribute to reducing the level of violence in our society.
Jeffrey D. Weidenhamer, Ph.D is a Trustees' Distinguished Professor at Ashland University and Professor of Chemistry.