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.
In addition, from 1991 to 2014 violent crime arrest rates fell 50 percent for adults aged 18–24, but increased 21 percent for those aged 50–54, signifying a crime shift as the younger offenders of the ’90s, who had been contaminated, grew older, according to research by Rick Nevin, senior economist with ICF International.
Lead exposure has decreased dramatically in the last 30 years due to lead bans, but experts point out that crime and lead-poisoning hot spots still remain in the United States.
The Los Angeles County Department of Public Health has found the highest concentration of elevated blood lead levels in people under 21 years of age in South Los Angeles, an area with one of the highest crime rates in the county.
This section of Los Angeles is adjacent to Vernon, a city where a battery recycling plant run by Exide Technologies was allowed to operate under a temporary permit and spew illegal amounts of lead and other toxins into the air for more than 30 years before closing in 2015.
Community leader Monsignor John Moretta, who lives in the area, said he is very concerned about the lack of information in the community about the problem of lead contamination. He compared it to a recent major gas leak in Porter Ranch, south of Los Angeles, which caused thousands of residents to evacuate the reeking area and spawned countless lawsuits.
But you can’t smell lead, said Moretta.
“I just wish we could smell it. Maybe there’d be more protests. There’d be more people, so much concern. The politicians and all of the above would be more concerned about it.”