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Growing Food in City Soil

By David Glenn

It's an increasingly common sight in neighborhoods in Baltimore, Detroit and other American cities: Residents have reclaimed abandoned lots by planting gardens. Those projects have been praised for building social solidarity and improving local access to fresh produce, among other benefits.

But planting urban gardens is not without risks. Today's vacant lot may have been yesterday's dry-cleaning operation, aluminum factory or bus depot. "Gardeners may not know what sorts of contaminants are there or how to test for them," says Brent F. Kim, MHS '08, a program officer at the Center for a Livable Future (CLF). With colleagues from the School and Baltimore's Community Greening Resource Network, Kim recently conducted a study of what community gardeners know and believe about the risks of planting in urban soil. They found that gardeners have some awareness of specific dangers, but often have a spotty understanding of how to reduce exposure. Many overestimate the effectiveness of using raised beds, for example, and may be unaware of important practices such as not planting next to buildings that may shed old paint. The study was published in PLOS ONE in February.

In Baltimore and other urban settings, the most notorious soil contaminant is lead. But that is only the beginning: Arsenic, cadmium, cleaning solvents and many other contaminants have been found in soil in various parts of the city. CLF's Maryland Food System Map team collaborated with the study authors on an online map of environmental hotspots in Baltimore.

Unfortunately for community gardeners, soil tests can be limited in scope. "The tests that are typically available only include a few chemicals and may not tell the whole story," says Keeve E. Nachman, PhD '06, MHS '01, director of the CLF's Food Production and Public Health Program and principal investigator on the project.

While the researchers note that the risks of contaminated soils should not be taken lightly, they emphasize the importance of not deterring people from gardening. "Overall, participating in community gardening is a very healthy activity, one that benefits not just gardeners but their neighborhoods and the city as well," says Melissa N. Poulsen, MPH, a PhD candidate at the Bloomberg School and co-author on the study. "We want to encourage people to garden. We just want them to do so safely."