LOS ANGELES—Since the early 1990s, crime dropped a whopping 78 percent in Los Angeles, a city well-known for its gang violence and deadly riots.
Crime rates fell all across the country during that time, and researchers say evidence shows the reason may be the decline in the use of a certain “supertoxin.”
This substance is lead, a heavy metal that can increase the risk of many ailments, such as cancer, heart disease, and stroke, as well as attention, behavioral, and learning problems, especially in children. Researchers say they have found negative effects at every level of lead exposure, leading the Centers for Disease Control to declare that there is no known safe blood lead level in children.
Yet many people still do not truly understand the risks of lead that still remain in places like urban soil, old house paint, and lead-containing pipes, said doctors and other experts in environmental toxicology and public health at a recent community forum on toxic metals in Los Angeles.
“We’ve underestimated the impact of lead and arsenic and other toxins,” said Dr. Bruce Lanphear, professor at Simon Fraser University in Vancouver, Canada.
Lanphear and his colleagues found that in 6-year-old children, every five micrograms per deciliter of increase in blood lead levels increased the risk of being arrested for a violent crime as a young adult by almost 50 percent, according to their 2008 study “Association of Prenatal and Childhood Blood Lead Concentrations with Criminal Arrests in Early Adulthood,” published in the journal PLOS.
Other studies have found similar results.
“Childhood lead exposure increases the likelihood of behavioral and cognitive traits such as impulsivity, aggressivity, and low IQ that are strongly associated with criminal behavior,” according to a study by Jessica Wolpaw Reyes from Amherst College for the National Bureau of Economic Research in 2007.
The study found that the phase-out of leaded gasoline was responsible for approximately a 56 percent decline in violent crime in the United States.
