While the nation seemed only to turn its attention to lead poisoning with the break of the Flint water crisis in 2014, lead exposure has been plaguing vulnerable communities across the country for decades.
Activists across the country have fought for years to spread awareness on this issue and push governments of all levels to take steps to protect their communities.
Even the attention on Flint was short-lived. Media attention is fleeting and people soon turned their attention to the next event receiving mass coverage. The Flint was sidelined and, along with many other cities across the nation, continues to suffer the effects of lead exposure.
With so little attention paid to the lead crisis, it is unsurprising that so many people are ignorant of the wide range of consequences of exposure. The common association is with illness and, in the most tragic cases, death. While this is true, there is much more nuance that must be taken into account if we are to fully understand what led poisoning does to individuals, families and communities.
While there are many topics that warrant our attention, I want to focus here on the connection between lead exposure and crime rates. During the ‘80s and ‘90s, researchers began uncovering this link, eventually developing the lead-crime hypothesis. The hypothesis was based on two principles:
1. Lead exposure in children leads to the development of behavioral problems, resulting in issues such as poor impulse control.
2. The lasting effects of these issues impact their future behavior, increasing the likelihood that crimes, often violent, will be committed in adulthood.
Initially, this hypothesis was met with skepticism. Though lead is known to cause behavioral and development problems, there was no clear causal relationship between lead exposure and crime. If we were to see the relationship as more than corollary, other factors such as poverty would have to be taken into account. For example, we know that lead exposure is highest in poverty-ridden areas. We also know that crime is higher in these areas. So, if we want to establish a causal connection, we would have to show that lead distinctly impacts crime in a way that cannot be explained by other variables.
Until recently, no studies were able to make this causal connection. However, in 2016 and 2017, three papers were published by researchers at various universities that changed this. All three studies isolated the impacts of lead upon crime, finding every time that exposure leads to large increases in crime rates.
Though all three studies provide important insights, I will focus mostly on the first study, released in 2016 by Dr. James Feigenbaum from Harvard and Dr. Christopher Muller from University of California, Berkeley. They focused on crime rates and lead exposure in the late 20th century. To determine if a causal relationship between these factors existed, they compared multiple cities based on the materials with which their pipes were made because, during this period, people were exposed to lead most often through drinking water pumped through these pipes.
The researchers did not compare cities using lead pipes with cities with pipes made of different materials — this often corresponds to the wealth of a city. And so doing this would confound the results of lead with those of poverty, making it impossible to separate the impact of each variable. Rather, they focused on the fact that the lead from pipes contaminates the water only if the water is acidic.
So they set up two groups. First, we have the cities with lead pipes without acidic water — those which would not be exposed to lead through drinking water. The second group was made up of cities with lead pipes and acidic water, meaning their residents would be exposed to lead. They compared the homicide rates in these cities, lagged twenty years to allow the children to grow up. This allowed them to see how lead exposure has lasting effects on one’s behavior.
Their findings were clear: The homicide rates in cities in which children are exposed to lead are significantly higher once these children grow up than the rates in cities without such exposure.
The other studies find similar results. The second study conducted found that, even within the same community, children who had the same economic status, attended the same schools and lived in the same neighborhoods exhibited very different behaviors based on lead exposure. Those exposed to lead faced much higher rates of suspension and were more likely to be incarcerated in juvenile detention centers.
The final study compared children who received government intervention to prevent and remedy the impacts of lead exposure with those who did not. Consistent with the results of the previous papers, the researchers found that those who received assistance exhibited significantly less antisocial behavior, facing fewer suspensions, expulsions and arrests than those who did not receive similar help.
The problem of lead exposure needs to remain on our radar. This means supporting activists who are fighting for their communities, pushing our government to take care of the problem for which they are largely responsible and keeping in mind how people have been impacted by lead exposure in so many ways beyond what we may expect. The consequences of exposure upon the crime rate is only one example of a key factor we have neglected.