EPA Lowers Soil Lead Screening Levels – Here’s What It Could Mean for Households Across the U.S.

As spring turns to summer in the U.S., kids are spending more time outside. Playing outside is vigorous in many ways, but it also comes with its own set of risks. One that many families may not be aware of is exposure to lead in the soil, which continues to be a sedate problem, especially in cities.

Children can be exposed to lead by swallowing or inhaling soil while playing. Adolescent children often put their hands in their mouths and may get dirt on their hands. Children and pets can also pick up lead dust from indoor soil. And anyone who eats fruit or vegetables grown in contaminated soil can ingest lead.

In early 2024, the U.S. Environmental Protection Agency lowered Lead screening level in residential soils from 400 parts per million — the standard that existed more than 30 years ago — to 200 parts per million. This more protective, lower number reflects current understanding of soil as a significant source of lead exposure for children.

EPA officials said the agency will typically take a more conservative approach in homes exposed to lead from multiple sources. 100 parts per million screening level.

This novel level is not a cleanup standard; it is a threshold at which EPA will make site-specific decisions about how to protect people. Actions could include providing information about lead in soil, recommending ways to reduce exposure, or removing lead-containing soil and replacing it with neat soil.

This standard is intended to serve as a guide for EPA assessments of residential soils around contaminated sites under two federal statutes. Superfund Law applies to hazardous waste that was improperly produced or disposed of before 1976, whereas in 1976 Resource Protection and Recovery Act regulates the generation and disposal of hazardous waste starting this year. Over 4,000 sites nationwide are currently being cleared under these two acts.

I’m learning urban lead poisoning in children from soil and other sources, and I worked with colleagues to analyze tens of thousands of soil samples collected from typical homes by scientists and citizens throughout the United StatesThis work is ongoing, but our recently published results show that potentially harmful exposure to lead from soil is lower under the novel EPA standard. much more widespread than many people – including public officials – realize. Reducing this risk will be a very long-term effort.

Toxic legacy

Lead exposure has affected communities across the United States, especially lower-income communities of color. Many factors have contributed to this, including lead in gasoline, water pipes and paintIn addition, redlining and other regulations have trapped vulnerable families in substandard housing that often contains lead paint and is located in areas heavily polluted by traffic and industrial sources.

Lead affects many parts of the bodyincluding the brain and central nervous system. Exposure to high levels of lead in childhood can lead to lower educational outcomes and lower earning potential.

Since the federal government began to severely restrict lead production and exploit in the 1970s, the percentage of U.S. children considered to be affected by lead, based on current standards, has fallen dramatically. That means that tens of millions of U.S. children are at significantly reduced risk of cognitive impairment from lead exposure. In the 1970s, that number was close to 100 percent; today it is about 1 percent, or about 500,000 children.

But many urban children are still exposed to risky levels of lead, and soil exposure is not addressed by regulations that have reduced other sources of lead. Lead in soil comes from degraded lead paint, pollution deposited by cars that have burned leaded gasoline for decades, and emissions from factories and industrial facilities.

Lead in soil is a common risk

Our national analysis of samples taken in 16 cities found that of 15,595 soil samples taken from households, 12.3% – or one in eight – exceeded the old federal level of control 400 parts per million. When the standard is lowered to the proposed level of 200 parts per million, 23.7% of households – almost 1 in 4 – contain a lead hazard.

These samples were typically collected in sets, with one sample taken near the exterior walls of the house where the highest soil lead levels are expected, a second in the garden and a third near the street where elevated lead levels may also occur.

If our findings are extrapolated nationwide, they indicate that about 29 million households out of the 123.6 million that were recorded in the 2020 census may be exposed to soil lead hazards and should take steps to mitigate them. Using the EPA’s ambitious target of 100 parts per million, our analysis indicates that about 40.2% of households may be affected—equivalent to nearly 50 million households nationwide.

Not all communities in our study have similar risk profiles. In Chicago, for example, 52.8 percent of the household soils we tested contained more than 200 parts per million of lead. Samples from parts of several mid-sized cities, including Springfield, Massachusetts, and Chattanooga and Memphis, Tennessee, had comparable percentages.

It is arduous to fully assess soil lead burdens in individual cities for several reasons. First, the citizen science dataset we used in our analysis was collected by private citizens under certain guidelines rather than under the strict scientific protocols that the EPA would follow. Second, there is no other systematic, comprehensive measure of household soil lead values ​​across the United States that could be used to assess the accuracy of the community science samples.

The first step is to cover the soil

Because there is so little data on soil lead levels, it is not yet possible to determine which households are at greatest potential risk. Without this information, the true cost of mitigating the problem is also unknown.

Full remediation, which involves removing contaminated soil and replacing it with neat soil, can cost between From 10,000 to 30,000 US dollars per household. Typically, the cost of this type of voluntary cleanup is paid by the homeowner, although some states may have assistance programs.

At that rate, the price tag for mitigating all households nationwide whose soils are predicted to be above the novel EPA standard will range from $290 billion to more than $1.1 trillion. Remediating soils in households involves multiple steps, including: soil testing and dust level monitoring. If done incorrectly, it could actually result in lead-contaminated soil and dust being dispersed beyond the cleanup site.

Given this projected price tag, my colleagues and I do not expect such a program to be proposed anytime soon. But there is a faster and much cheaper strategy: covering existing soils with neat soil or mulch. This is an imperfect solution, but it addresses the immediate problem of lead exposure for children living in such areas.

Capping is not a constant solution because the land cover could be disturbed, which would again make lead-enriched soils an lively risk. However, even covering a contaminated site with neat soil will permanently dilute the total lead concentration at that site. Almost all lead deposited by human activity is captured in top 10 inches of soilAdding another 10 inches of neat soil on top will reduce the lead concentration in the soil by half.

It’s a cliché, but nonetheless true, that the solution to contamination is often dilution. I believe this basic strategy is an immediate way for cities to begin to address their novel lead challenge.