From vertical gardens to succulent gardens to community vegetable gardens like the San Francisco garden pictured above, city dwellers all around us have started to embrace their (hopefully) green thumb. For city dwellers in particular, community gardening gives us much-needed “outdoor time” with like-minded people, with the added gift of hyper-local produce available throughout the growing season. These benefits have led to increased participation in residential and community gardens in major cities across the United States.
While many people are jumping on the cool garden bandwagon to reap the obvious, green benefits, it’s important to consider the potential side effects that come with urban farming. Urban soil is not only closer to possible sources of pollution, such as traffic and industrial areas, but could also contain residual chemicals from past land use. Residential land previously occupied by industrial buildings contains dangerous levels of toxins like lead, which can poison residents and contaminate food grown on site. But it doesn’t take an old plant to contaminate your backyard. Soil can absorb and hold toxins left over from something as small as the previous owners dumping cleaning water down the drain or out the back porch.
Baltimore researchers published an article in PLOS ONE earlier this month, assessing Baltimore’s community gardeners’ knowledge of the risks of soil contamination and exploring steps that can be taken to mitigate the dangers of urban pollution in urban gardens.
The authors, from Johns Hopkins, the University of Maryland and the Community Greening Resource Network, conducted interviews with members of the Baltimore Community Garden and found that, unfortunately, gardeners generally seem unconcerned about potential contaminants. in their soil. Those working in established community gardens were the least worried as they often assumed that any soil contamination issues had been resolved within the first days of using the garden.
When participants were asked what soil contaminants they were aware of, lead was the most common answer – likely due to city interventions regarding lead poisoning – with 66% of surveyed gardeners mentioning it in their interviews. The study results also indicate that gardeners are more concerned about the presence of pesticides and other added chemicals than most other residual chemicals in the soil. Soil quality and fertility have even taken precedence over the presence of contaminants for some gardeners.
By interviewing Baltimore officials familiar with community gardening practices and soil contamination issues, the researchers determined key steps to keep gardening sites safe. Above all, the officials suggested the creation of a central source of information related to soil contamination problems. Similar projects related to regulation and urban agriculture are already underway in places like Los Angeles, though these resources aim to help residents navigate the maze of confusing legislation related to urban agriculture, and focus less on providing information on how to assess the safety of specific plots. earthen.
The authors suggest other important ways to determine the safety of a garden site, including learning about the site’s past uses and testing the soil for lingering chemicals, which may not seem necessary to those who are not. not trained in town planning or chemical analysis. They also recommend that urban area officials provide services that will encourage the use of these tools and help gardeners find and interpret the results of soil tests or historical research.
In the meantime, the authors suggest limiting exposure to potentially contaminated sites. For example, we should minimize contact with dirt from garden sites by washing our hands and removing shoes before entering indoor spaces. Many gardeners interviewed have tried to alleviate this problem by using raised beds, which they claim eliminates concerns about contaminants in home garden vegetables. However, researchers have found limitations to this method, and it shouldn’t be seen as a solution to everything. Raised beds do not prevent contamination from the soil around the beds, which can still be ingested or tracked into the home, and surrounding pollutants have been known to blow into beds or seep into the ground at from the treated wood used to build the structures.
Urban community gardening is a trend that is here to stay, and we have it to thank for fresher local produce, a greener environment, a greater sense of community, and for the physical, and sometimes therapeutic, activity that she provides. The potential dangers associated with gardening in urban areas probably do not outweigh the benefits, as long as gardeners remain diligent and become better informed. Although their study focused on a limited group, the findings of this article draw attention to the fact that they are not. So the next time you’re digging into a patch of grass in your garden with visions of vegetables or working in your local community garden, take a minute to reflect on what you know about your area, discuss past developments with longtime residents, and most importantly, clean up afterwards.
More information on soil testing and good gardening practices can be found on this EPA site.
UPDATE: This post has been updated to clarify that statistics on gardener awareness of soil contaminants only measure awareness, not concern for the soil they are working with. It has also been amended to clarify that raised beds provide some protection against soil contamination from the surrounding area, although they have limitations.
Quote: Kim BF, Poulsen MN, Margulies JD, Dix KL, Palmer AM, et al. (2014) Knowledge and perceptions of urban community gardeners on the risks of soil contamination. PLoS ONE 9(2): e87913. doi:10.1371/journal.pone.0087913
Picture: People’s Garden Netting Netting by SPUR