Identifying Lead Contamination at the Source of Exposure:Collaborating with Community Members to Protect Public Health

While urban gardeners may test soil for lead and other contaminants, the practice is not common for the non-gardening resident or parent. However, soil contamination can present an important source of childhood exposure to lead, a heavy metal that can hinder neurodevelopment in young children. Many cities have recommendations for how to address soil contaminated with lead, but since testing isn't common, many residents don't know they should take these actions to protect their family's health.

Over the past year and a half, we tested soil in northern Brooklyn through three types of collaborative initiatives with community organizations and local colleges. In the first, students in an environmental science course collected 108 soil samples from public parks and street trees, recording the location by GPS and taking a photo of the site with a smartphone. Students analyzed these samples for lead with a field kit as part of their coursework, and all soil samples were then measured by bench-top X-ray fluorescence (XRF) analysis.

In the second initiative, we collaborated with a community environmental organization and participated in a farmer's market to invite and train 24 community members to use a field kit to collect 5 to 7 soil samples from their home. Participants brought back samples to confirm the field kit readings by a technician and XRF analysis. These backyard samples highlighted the potential high levels of contamination present in the neighborhood. To broaden the scale of sampling and better understand the distribution of contamination, we offered to visit homes and conduct free soil testing for local residents in a third initiative.

We found 81% of the soil samples analyzed by XRF from 63 homes exceeded the New York Soil Cleanup Objective of 400 mg/kg lead, which is also the EPA hazard standard level for bare soil where children play. And 36% of samples exceeded EPA's 1200 mg/kg hazard standard for other residential soil. Even these levels may be too high to sufficiently protect the health of children; the California Human Health Screening Level is 80 mg/kg for lead in residential soil. Given that our soil testing in northern Brooklyn identified lead concentrations far above the guidelines that protect human health, we recommend instituting widespread testing to help residents identify possible soil contamination.