In Springfield, Massachusetts, and Hartford, Connecticut, something troubling has been hiding in the dirt beneath children's feet — and now researchers have figured out where to look for it.
A study published in the journal GeoHealth by University of Vermont scientists reveals that patterns of soil lead contamination in these two Northeastern cities closely mirror neighborhood demographics. After testing roughly 300 soil samples from residential areas in both cities, researchers found that income, housing type, age, and race emerged as key predictors of contamination — findings that could help communities target their cleanup efforts where they're needed most.
The research comes at a time when an estimated 25 to 40 percent of homes in the United States sit atop lead-contaminated soil, a toxic heavy metal that can harm children's brain development. While public health experts have long known that older industrial cities face elevated risks, pinpointing which neighborhoods within those cities carry the greatest burden has proven difficult — until now.
Lead author Nico Perdrial, a professor in UVM's College of Arts and Sciences and affiliate of the Gund Institute, says the implications are significant. "Some groups are much more likely to live in highly lead-contaminated soils," she noted. The pattern was especially stark in Hartford, where soils were more contaminated overall than Springfield's, and where children of color in multifamily housing faced the highest exposure risk.
The researchers fed their soil data into a model along with census and tax records, including housing type, residents' racial demographics, children's ages and numbers, and residential property values. What emerged was a clear picture of environmental inequality baked into the landscape.
In Springfield, neighborhoods whose populations of white, non-Hispanic residents fell below the city average had 1.7 times the chance of elevated soil lead. Within those areas, locations with multifamily housing and more children than average faced a striking 2.4 times greater likelihood of high contamination.
Hartford told an even more damning story. Neighborhoods once rated "desirable" on historic Home Owners' Loan Corporation maps — the infamous redlining documents that guided 20th-century mortgage lending — were less than half as likely to have high soil lead. Those rated least desirable? Twenty percent more likely. And within those same underserved neighborhoods, soil surrounding multifamily homes was 40 percent more likely to register high lead readings.
"Redlining drove lead exposure much more than any other parameter we measured," Perdrial said. "It's an indication that a legacy of environmental racism exists in the soil. It's not just the contaminant that is a legacy. The soil has this memory that we cannot just eliminate by changing policies."
But here's where the research offers reason for optimism: the method works. The statistical model is replicable, and Perdrial is urging colleagues to apply it to other industrial cities. By identifying which neighborhoods face the greatest risk, communities can deploy testing and mitigation measures far more efficiently — putting resources where they're most needed before another generation of children is exposed.
"This is where children play," Perdrial said of the residential areas her team studied. Now, thanks to this research, cities have a new tool to protect them.