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    Why Bioremediation Is Scarce in Urban Gardens

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    "Earth Repair," by Leila Darwish, is essential reading for anyone who wishes to transform environmental despair into constructive action.
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    Bioremediation’s use of naturally occurring organisms, apparent affordability and minimal disturbance to soils all add to its attractiveness.

    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.

    Governmental agencies
    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
    accompany bioremediation.

    Additionally, many
    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.

    Published on Jul 23, 2013


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