Rates of violent crime can vary tremendously between American counties. For example, one community may experience only 100 crimes per 100,000 people, while another of about the same size and population may have more than 3,000 per 100,000.

Why such a huge difference?

Conventional thinkers blame poverty, lack of education and opportunity, and bad role models. But a number of scientists and researchers now say there is substantial evidence that environmental toxins such as lead and pesticides are implicated, particularly when children are exposed to them early in life.

Let’s focus on lead:

Herbert L. Needleman, of the University of Pittsburgh’s School of Medicine, did much of the influential research that led the government to ban lead in fuel in 1979. He was among the early researchers who established that children with elevated lead levels had lower IQs, poor reading skills and problems paying attention. Prompted by “Crime and Human Nature,” a controversial book published in the mid-1980s that explored the body’s role in criminality, Needleman began wondering what role lead exposure might play in criminal behavior.

He studied 300 7-year-old boys in primary school and measured their bone lead concentration, then measured the burden of bone lead against reports of antisocial behavior from the teachers, parents and the youngsters. He retested the youngsters two years later and repeated the behavioral survey when they were 11 years old.

At age 7, parents did not report significant problems associated with lead, although teachers were beginning to see social problems and delinquent and aggressive behavior. By 11, both parents and teachers of high-lead children were reporting significantly more social problems, delinquent and aggressive behavior, acting out, anxiety and/or depression, and attention problems. High-lead students also reported more delinquent behavior themselves. These behavior problems “went up in direct relation to the lead levels in the bone,” Needleman said in an interview.

He also found much higher lead rates in a group of juvenile delinquents than in a control group. He used 416 youths–216 delinquents and 200 in a control group. Adjusting for such factors as race, parental education, occupation, family size and crime rate in the neighborhood the youths came from, he found those with high lead levels were twice as likely to be delinquent than those with low levels.

He estimates that 11 to 38 percent of the nation’s delinquency is attributable to high lead exposure, a finding he presented at a recent pediatric meeting in Boston. Exposure has come down dramatically since lead was banned in gasoline in 1979. Needleman points out that violent crime has decreased across the country in the past decade–the time when babies born in the late ’70s would have entered the period of maximum criminal activity–and SAT scores have gone up. “I just think it’s very interesting. It’s like one piece of evidence.”

Lead, he says, is “a brain poison.” It creates biochemical changes that result in lower IQ, an inability to sit still and language and reading problems. “The brain is important in regulating behavior, particularly the prefrontal lobes. They are involved in making decisions, choices, resisting impulses.” A number of studies of criminals have found disturbances in the prefrontal lobes. A study Needleman did of young children exposed to lead in 1976 found those with elevated levels were seven times more likely to fail out of high school 12 years later, proving that the effects of lead are permanent. “If you don’t have a high school diploma and you can’t read, you are going to have a hell of a time making a living,” he said.

Roger D. Masters, a Nelson A. Rockefeller professor of government emeritus at Dartmouth College and president of the Foundation for Neuroscience and Society, has broken the academic mold by combining chemistry and public policy, and it’s taken him right to the heavy metals such as lead, manganese and cadmium. “The heavy metals affect the neurotransmitters,” he said. “Manganese has the opposite effect of Prozac. It reduced serotonin.”

Silicofluoride Fluoridation Chemicals and Elevated Water Lead Levels

Masters has looked at the crime rates and found a disturbing correlation between high lead rates in certain communities and the use of silicofluoride to fluoridate water systems. In most of the states where he has measured high lead levels, he has found them to be much higher when silicofluoride is in the water. “If you look at violent crime, you find the same kind of thing. A kind of doubling of the crime rates where silicofluoride is used. It seems to have the effect of breaking down barriers between the blood and the gut. It appears that silicofluoride increases the amount of toxins that get into the blood.”

He looked at towns in Massachusetts that had more than 10 toxic spills over a two-year period. If silicofluoride was not in the water, fewer than 1 percent of children had high lead levels. If silicofluoride was in the water, five times as many children had high lead levels.

“We’ve got to start looking seriously as a culture at what we are doing to ourselves through chemistry. One clear effect is toxic chemicals can destroy inhibitory systems and cause violence. Absorption of lead depends on a number of things, and one is diet. Lead and calcium bind to the same place. A child without calcium is likely to pick up more lead.”

He closed the interview with the observation that the Roman Empire fell because the Romans used lead to sweeten wine.

These researchers are crossing the borders between science and public policy, and they are finding that environmental pollutants are key players in causing violent behavior, as well as diseases. Their findings are so compelling, they must be included in any master plan to reduce violence in this country.