Urban gardening is a fundamentally
positive trend. However, the toxins that plants extract from city soil
and deliver to hungry human mouths form an unsavory dark side to the
movement. As the popularity of urban gardens increases, publicizing
gardening practices is critical.
Although the public is generally
aware of the risks of growing plants in metropolitan soil, explicit
guidelines to garden siting and information regarding vegetable toxin absorption have heretofore been unclear and insufficiently
disseminated. A recent study published in the journal Environmental
Pollution by researchers from the Technical University of Berlin
helps clarify these issues.
The study yielded three primary
insights. First, it confirmed vegetables' tendency to extract heavy
metals from soil. For example, many tested vegetables contained
dangerously high levels of lead, which is widely known to cause developmental
disorders, brain damage, and generally punish the body's organs.
Second, the entire spectrum of vegetables involved tested positive
for contaminants, contradicting the belief that some vegetables are
safer choices for dangerous soils. Fortunately, the study's final
conclusion points to a primary problem, as well as a potential
solution. Gardens closest to high traffic flow are the most toxic.
But barriers of foliage or buildings between gardens and traffic
significantly reduced levels of heavy metals.
Based on the results of this study, we
can extrapolate some key guidelines to safe urban gardening.
Research the land in which you plan to plant. Check the city land
planning office for information concerning what went down on the
ground you're considering. If you really want to get your hands
dirty, enlist nearby health/environmental agencies or a local
university's agricultural department to conduct some basic soil
tests. If you find contamination, plant in pots or raised beds lined
with protective sheets. Finally, if you are near a high traffic
avenue, build a wall or thick hedge to defend against toxic dusts.
With these guidelines in mind, the benefits of urban gardening – cleaner
air, fresher produce, exercise outdoors, urban beautification, and a
deeper connection to nature – begin to outweigh the potential risks.
"Rooftop Garden" by Jim Crossley on Flickr courtesy of Creative Commons Licensing.