Prevention key to getting the lead out

Bill Knight column for Thurs., Fri., or Sat., July 26, 27 or 28


Hindsight is 20/20 but useless unless the past can be applied to the future. A recent study provides a chilling object lesson about unintended consequences by linking lead contamination generally and gasoline exhaust particularly to problems or even violence now.

Childhood exposure to lead dust has long been linked to lasting physical and behavioral effects, but now lead dust from vehicles using leaded gasoline has been tied to instances of aggravated assault two decades after exposure, says toxicologist Howard Mielke.

Vehicles using leaded gasoline that contaminated cities’ air decades ago have increased aggravated assault, says research by Mielke, a professor in the Department of Pharmacology at the Tulane University School of Medicine, and demographer Sammy Zahran at the Center for Disaster and Risk Analysis at Colorado State University.


Their findings, in the journal Environment International, compared the amount of lead released in Chicago and five other cities from 1950 to 1985, when leaded gasoline caused an increase in airborne lead dust exposure. Approximately twenty years later, after the exposed kids grew up, there were correlating spikes in the rates of aggravated assault.


Correlation is not cause, of course, and other simultaneous factors could contribute to violence. However, Mielke and Zahran controlled for other causes, such as community and household income, education, improper handling of lead-based paint, policing efforts and incarceration rates, and they still found that for every 1 percent increase in tons of environmental lead released 22 years earlier, the present rate of aggravated assault was raised by 0.46 percent.

“Children are extremely sensitive to lead dust, and lead exposure has latent neuroanatomical effects that severely impact future societal behavior and welfare,” Mielke said. “Up to 90 percent of the variation in aggravated assault across the cities is explained by the amount of lead dust released 22 years earlier.”

The National Institute of Environmental Health Sciences/National Institutes of Health says, “Lead is a highly toxic metal found in small amounts in the Earth’s crust. Lead and lead compounds have been used in a wide variety of products including paint, ceramics, pipes, solders, gasoline, batteries and cosmetics. Since 1980, federal and state regulatory standards have helped to minimize or eliminate the amount of lead in consumer products and occupational settings. While extreme lead exposure can cause a variety of neurological disorders such as lack of muscular coordination, convulsions and coma, much lower lead levels have been associated with measurable changes in children’s mental development and behavior.”

The adverse effects of lead fall into four broad types, according to LeadSafe Illinois, an initiative to eliminate childhood lead poisoning at Loyola University’s Civitas Child Law Center and Policy Institute:
HEALTH: At high levels, lead poisoning causes damage to children’s central nervous system, kidneys and reproductive system. It can cause permanent brain damage. Preventing childhood lead poisoning in the U.S. could save up to $44 million annually in health care costs.
DISABILITIES: Lead in the blood is linked to symptoms of Attention Deficit Hyperactivity Disorder (ADHD), hyperactivity and speech disorders, behavioral disorders ranging from impulsivity and delays in reaction time to moods and decision-making, and lower IQ as measured by IQ tests (it’s estimated that kids who are lead poisoned below 10 micrograms per deciliter – the threshold for most legislation and the Center for Disease Control – will lose 5-7 IQ points).
SCHOOL & WORK: Childhood lead poisoning can affect the ability of the brain and nervous system to work together to connect thinking and behavior, so it’s tied to a decrease in math and reading scores, and a need for special education due to impaired neurobehavioral function. Since lead poisoning is linked to life-long illnesses and lower academic achievement, it affects the ability to hold down a job. (For each IQ point that’s lost, a child makes an estimated $16,809 less over the course of his or her lifetime.)
CRIME: Lead poisoning in childhood can lead to aggression and criminal behavior and it’s been connected to more arrests and/or arrests for violent offenses as adults. The estimated total direct costs of violent crimes linked to early childhood lead poisoning is almost $1.8 billion

“No amount of lead in the body is good,” reports Lead Safe Illinois. “Exposure to lead in both large and small amounts can cause lead poisoning in adults and children.”

Years-old contamination from leaded gasoline is just one exposure affecting society.

“Lead dust can be created from opening and closing the doors or windows inside a home painted with lead-based paint,” Lead Safe Illinois continued. “A child is exposed to a very small amount of lead when he or she puts his or her mouth on toys covered with lead dust. Small doses of lead can build up in the bones and teeth, which can stay there for years.”

One wonders what current activity could affect us decades down the road.