Study Raises Concerns About Soil Contamination in Urban Farms

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Photo by Colby Ware, via OSI
Photo by Colby Ware, via OSI

We love urban gardens for lots of reasons. They turn vacant lots into zones of food production, fill our farmer’s markets with delicious produce, and give backyard hobbyists a way to spend their Sundays. But there’s a potential downside to produce grown in urban soils, according to Johns Hopkins: Soil contamination.

According to a new study from the Johns Hopkins Center for a Livable Future, perhaps our favorite of Hopkins’ many institutes, soil in Baltimore (and other urban areas) is often close to pollution sources, which lead to higher concentrations of soil contaminants. But many urban gardeners don’t know that. “People may come into contact with these contaminants if they work or play in contaminated soil, or eat food that was grown in it. In some cases, exposure to soil contaminants can increase disease risks, especially for young children,” CLF’s Brent Kim told the Hopkins Hub.

“Our study suggests gardeners generally recognize the importance of knowing a garden site’s prior uses, but they may lack the information and expertise to determine accurately the prior use of their garden site and potential contaminants in the soil,” explained Keeve Nachman, lead author of the study. “They may also have misperceptions or gaps in knowledge about how best to minimize their risk of exposure to contaminants that may be in urban soil.”

For more information about how to safely garden in (and consume food from) potentially contaminated soils, check out this useful handout from the EPA.

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  1. As one of the authors on this study, I’m happy to see our research discussed here, and we certainly hope to encourage gardeners to take precautions so they can avoid exposure to soil contaminants. However, I think the title of the article is a bit alarmist. While the public health risks associated with gardening in contaminated soils should not be taken lightly, there are so many benefits to urban gardening (for both gardeners and Baltimore as a city) that I would hate to see a headline like this deter people from gardening or eating produce from Baltimore’s wonderful farms and gardens. I would also note that most of the true urban farms in Baltimore (as opposed to community gardens) who are selling produce take soil contamination very seriously to ensure that their produce is free from contaminants.

  2. Hello,

    As an urban farmer in Baltimore, I agree with Melissa that the title and tone are a bit sensationalist. Urban production farms will be required by new city law’s to test for soil contaminants, and nearly all that are operating with business principles (bringing to market) have already done so. The Farm Alliance of Baltimore City requires soil tests of its member-farms, and have even provided consultation to city government on best practices. The distinction between urban farms and community gardens is not always clear, but this article doesn’t seem to make any.

    Furthermore, while urban soils have a higher risk of contamination of certain metals, rural soils have their downsides too – higher likelihood of arsenic because of historical pesticide use like DDT, and continual encroachment of pesticide drift. The important thing is to empower and educate gardeners and homeowners to know their site – its history, its current soil analysis, instead of instilling fear of eating and supporting produce from urban gardens or farms.

    For more information, next week we’re having a workshop on soil contamination in urban gardens – see (Real Food Farm, Farm Alliance of Baltimore City, UMD Extension and Future Harvest).


    Tyler C. Brown
    Farm Manager
    Civic Works’ Real Food Farm

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