By: Nathan Lamb

Once a staple of gasoline and paint, lead has long been recognized as a toxic contaminant, and a new study is suggesting it could have a direct relation to violent crime trends over the past 60 years.

Compiled by lead expert Dr. Howard Mielke of Tulane University, the study was featured in a recent news report by WWLTV of New Orleans.

Lead emissions from automobiles were central to the study, which evaluated more than 10,000 soil samples from around the city of New Orleans.

The study showed that areas with higher levels of lead exposure were typically the higher crime areas, adding it’s likely a significant factor behind criminal tendencies.

Mielke said the problem is that automobiles brought literally tons of lead into American cities over the latter half of the 20th century. He calculated that each gallon of leaded gas released one gram of lead into the environment and, since lead is a persistent contaminant, it generally stays in place until removed.

Lead dust from contaminated soil are particularly dangerous for children, because it can impede brain development and impulse control. The study suggested a 20-year time lag between increased emissions and rising crime rates.

Lead was first used as a gasoline additive in the 1950s and was banned in 1996.

Published in August of 2012, Dr. Mielke’s study tracked emissions and violence in six major cities from 1950 to 1985.

According to the study abstract, fluctuation of lead emissions appeared to explain 90 percent of the aggravated assault variations. All else being equal, the study had each 1 percent increase in emissions tonnage consistently resulting in a .46 percent increase in the aggravated assault rate a generation later.

The study also suggested increased prevention of childhood lead exposure could result in lower crime rates in the future.

In the meantime, Mielke suggested that lead contamination should be more of a national issue, noting there’s a Clean Air Act and Clean Water Act, but no Clean Soil Act.