Why Bioremediation Is Scarce in Urban Gardens
Packed with valuable, firsthand information from
visionaries in the field, Earth Repair (New Society Publisher, 2013), by
Leila Darwish, empowers communities and individuals to take
action and heal contaminated and damaged land. Encompassing everything from
remediating and regenerating abandoned city lots for urban farmers and
gardeners, to recovering from environmental disasters and industrial
catastrophes such as oil spills and nuclear fallout, this fertile toolbox is
essential reading for anyone who wishes to transform environmental despair into
constructive action. The following excerpt comes from chapter 2, “Earth Repair
and Grassroots Bioremediation.”
You can purchase this book from the Utne store: Earth Repair.
The urban gardener is in
regular physical contact with soil, breathing its dust and eating foods grown
from it. Few others have such an intimate relationship with city soils, a
resource that is seen by most others as something that only serves as a
foundation for buildings and roads. Logically then, gardeners
are concerned with soil contamination issues and are looking for simple and
low-cost means to address them.
For a number of years now,
urban gardeners and their supporting organizations have been aware of the
concept of bioremediation. Bioremediation’s use of
naturally occurring organisms, apparent affordability and minimal disturbance
to soils all add to its attractiveness. The idea of partnering with
life-forms such as bacteria, plants, worms and fungi (all of whom gardeners are
already familiar with) greatly adds to its appeal. Numerous scientific studies
have been conducted that support bioremediation’s effectiveness — there’s no
question that given the right circumstances, these organisms have the potential
to degrade, immobilize or sequester a variety of contaminants. Bioremediation would appear
to be an ideal and elegant solution to issues of soil toxicity. Why then, have
bioremediation techniques not yet been put into use broadly as a means to
remediate contaminated soils in urban gardens? Why are we not seeing citizen
groups applying the tools of bioremediation and publishing their results?
These are questions that I
have been asking for a number of years in my work designing ecologically and
socially regenerative systems in urban environments. In 2004, the Rhizome
Collective, an organization that I co-founded in Austin, Texas,
received a $200,000 grant from the US Environmental Protection Agency to clean
up a brownfield site located in the city. This cleanup primarily involved
removal of tons of trash and debris — a twisted mountain of concrete, rebar, wood
scraps, tires and carpet scraps — from a former illegal dumping site. Although
levels of organic and heavy metal pollutants on the site met residential
standards, concerns remained about the safety of gardening there, post-cleanup.
Unfortunately, funding in
the grant would not cover the cost of soil remediation. Shortly afterwards, I
was part of an effort to establish a community-based bioremediation plan in
post-Katrina New Orleans to help address residual hydrocarbon contamination
left behind from the storm. Compost teas were applied to areas known to be
affected by pollutants. While the program received donations of services from
soil testing labs, the funds were insufficient to carry out a properly managed remediation
program on the scale that was necessary.
The barriers to
community-based bioremediation are many. One such obstacle is that there is
still a great deal of mystique, particularly to the less scientifically
literate, surrounding bioremediation and its processes. This lack of
understanding can make bioremediation an intimidating prospect to many. The
vast majority of literature concerning bioremediation exists in scientific
journals, written in a dry academic style that is close to unreadable by the
layperson. The bulk of these studies are conducted in highly controlled,
sterile laboratory conditions, incredibly different from the diverse,
heterogeneous and competitive ecologies that exist in a garden environment.
In order for this boundary
to be spanned, a few individuals that are scientifically literate will need to
wade through the journals and distill a series of guiding principles and best
practices usable by the average gardener. From there, a push needs to made from
within and outside of academic institutions to conduct a greater number of
field-based trials, where proven bioremediation techniques are put to the test
in real-world conditions. Emphasis needs to be placed on techniques that are
simple, affordable and that make use of commonly available biological agents.
The focus of these studies should be on the top 12 inches of soil, the zone in
which the majority of urban gardeners are active. Partnerships between citizen
groups and academic institutions are vital, as universities have access to
technological resources that gardeners are commonly lacking but are necessary
to conduct such trials.
Cost is another significant
barrier to implementing bioremediation techniques. While bioremediation is
relatively inexpensive, especially when compared to more intensive means of
conventional remediation, its use still requires some expenses, particularly
when soil testing is involved.
For example, spreading spent
mushroom substrate over an oil spill could conceivably be done for little or no
cost. Testing the contaminated soil, however, to be sure that the total
petroleum hydrocarbons have been reduced to safe levels can be prohibitively expensive
— potentially hundreds or thousands of dollars. While the spent substrate
application may have been successful in degrading the oil, without verifiable data
to prove its effectiveness it is difficult to get the support needed to replicate
the process on a broad scale.
ideally would play a role in funding citizen-based cleanups, although they have
done very little to date. Most of the government funds that exist for
brownfield remediation go to large-scale developers, who are primarily
interested in meeting regulatory obligations as quickly as possible. These
developers typically favor a “dig and dump” approach to soil remediation,
rather than dealing with the longer time scale and other uncertainties that can
governmental agencies charged with environmental protection are reluctant to
work with citizen groups, fearing liability were something to go wrong.
Consequently, governmental agencies are commonly unfamiliar with small-scale bioremediation.
It is my belief that it is very much in the interest of government agencies to
alter this policy. As interest in community gardening increases, so will the
number of people wanting to partake in soil remediation. These people are going
to attempt remediation, whether or not they receive assistance from agencies. Therefore, it makes sense
for agencies to offer some form of guidance or assistance so that people do not
put themselves in harm’s way.
Part of this work would be
developing a solid method of risk analysis for exposure to soil toxins.
Currently, no such framework exists. It is important to be able
to answer important questions like “what is the danger of being exposed to a
particular contaminant in the soil, and further, what is the danger of that
being taken up into a plant and being passed into my body?” These aspects of
risk need to be weighed against all the benefits of gardening, such as improved
nutrition, physical exercise and enhanced community relationships. Developing
such a framework is a multi-disciplinary task, involving the fields of ecology,
toxicology, public health and medicine.
Developing a protocol for
qualitative soil analysis is another innovation that could reduce the cost of
bioremediation. It may be possible to create a method for assessing the quality
of soils using what are called bioassays. An example of a bioassay would
be testing seed germination rates in soils with known levels of toxicity. Using
this information, it could be possible to determine contaminant levels in soils
using only plant seeds, potentially cutting the cost of soil testing
Bioremediation holds great
promise for urban gardeners as a tool for achieving improved soil health.
Hopefully, in time and with the cooperation of institutional entities, it can
go from being an experimental technique to a broadly utilized strategy.
Scott Kellogg is the
educational director of the Radix Ecological Sustainability Center in Albany,
New York and author of the book Toolbox for Sustainable City Living. He has recently
completed a Masters degree in Environmental Science from Johns Hopkins
University, where he wrote his thesis on the topic of low-intensity,
community-based bioremediation techniques.
This excerpt has been reprinted with the permission of
Earth Repair: A Grassroots
Guide to Healing Toxic and Damaged Landscapes by Leila Darwish and published
by New Society Publishers, 2013. Buy this book from our store: Earth Repair.
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