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Introduction to Bioremediation: Nature’s Response to Environmental Contamination

Humanity's modern revamp of nature's million year old process and its importance in the future of environmental conservation

A million years ago, before humans completely altered the landscape, planet Earth had established itself as a biosphere regulated by the cyclical processes of nature’s elements. Waste materials from decomposed organisms yielded chemical energy that microorganisms desired and eventually expelled into carbon dioxide and water. A million years later, scientists would coin the term ‘natural bioremediation’ to describe this phenomenon, a necessity to sustain the life of an ecosystem (1).

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Image from Wikimedia Commons

In the late 20th century, George Robinson coined ‘bioremediation’ to refer to the use of microbes for a specific purpose: to clean up contaminated soil and groundwater (3,4). As a result of more industrialized communities, contaminants like hydrocarbons have disrupted the balance of a bio-geological system–a problem that has only magnified in recent years. The discovery of oil degrading bacteria in the 1940s hinted the possible extent of microbes’ metabolic abilities and its potential in combating environmental pollution (2). One could say that these microorganisms evolved from their counterparts a million years ago to adjust to the chemical imbalances in our environment, but the question lies in their capabilities to adapt and perform their roles as decomposers effectively.

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Image from A Citizen’s Guide to Bioremediation (3)
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Image from Bioremediation’s Integral Role in Ecosystem Restoration and Rehabilitation (9)

 

The offset of the process is fairly simple. As shown by the diagram above, the microbes consume the contaminants (which they would consider food) and other nutrients in order to convert them to water and harmless gases (carbon and ethene) (3). One of the notable advantages to bioremediation is that it doesn’t produce harmful waste products to the environment. However in order for bioremediation to be effective, certain conditions must be met, namely microbial structure, environmental conditions, and state of the contaminated site itself. In Mahjoubi and her associates’ study of microbial bioremediation with hydrocarbons, they determined that the presence of inorganic sources, high temperatures, and availability of oxygen (despite existence of anaerobic bioremediation processes) have considerable impact on microbial growth and efficiency (10). Variables like pH are dependent on individual microbes as some studies show microbial activity to be most active in acidic, neutral, and alkaline conditions (10).

 

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Image/Table from Microbial Bioremediation of Petroleum Hydrocarbon– Contaminated Marine Environments, Recent Insights in Petroleum Science and Engineering (10). This table shows elements various bioremediation strategies (treatment and added microbes), their effectiveness, and duration against hydrocarbons. 

Thanks to advances in biotechnology, scientists have devised methods in optimizing microbial capabilities as a response to large-scale contamination: bioaugmentation, biostimulation, and landfarming. Bioaugmentation adds a specific microbial species into the contaminated environment (3). This addition must be well-adapted to the polluted environment in order for the microbial growth to be effective. Biostimulation is the addition of growth-limiting nutrients to an indigenous microbe population and is often used when the site lacks nutrients needed for microbes to thrive (10). Landfarming combines bioaugmentation and biostimulation practices, involving the excavation of contaminated soil to be stimulated through aeration and/or the addition of nutrients or microbial species (10). Of the three, landfarming poses several advantages due to its relatively low costs and its implementation on marine pollution through ex situ decontamination, and is arguably the most effective out of the three treatments (10, 11).

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Image from Microbial Bioremediation of Petroleum Hydrocarbon– Contaminated Marine Environments, Recent Insights in Petroleum Science and Engineering (10). This image shows the amount of marine accidents in 1977, initially reported by the  Regional Marine Pollution Emergency Response Centre  (REMPEC).

But despite the popularity of bioremediation among professional settings all over the globe (the Mediterranean Sea being a common site for case studies), bioremediation efforts are notably absent in communities. The use of naturally occurring organisms, in situ treatment of the soil, and minimal disturbance of the environment would appeal to local gardeners as a solution to soil toxicity. However Scott Kellogg, co-founder of the Rhizome Collective, cited insufficient funds in building a remediation program necessary to clean up a brown site in their area despite receiving a $200,000 grant from the Environmental Protection Agency (6). Even though implementing bioremediation techniques are relatively inexpensive, soil testing makes up most of the cost and is necessary to determine the effectiveness of said techniques. In fact, cost of laboratory soil analyses, along with an overall low-level of scientific literacy, are cited to be the most significant obstacles to proper implementation in non-specialist communities (7). Most, if not all, of these case studies are conducted in controlled laboratory conditions with resources not normally accessible to the common man–a far cry from the diverse ecologies of a garden environment with resources found in the nearest Walmart. In order to truly make bioremediation a community practice, collaboration between citizen groups and academic institutions are necessary to mobilize hands-off governments and an informed citizenry.

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Image from Amazon Mycorenewal Project (8)

Although few, grassroots organizations have initiated a bioremediation program within their communities. One of these organizations, The Amazon Mycorenewal Project (AMP), works primarily in the Sucumbios province of the Ecuadorian Amazon Region to clean up 18.5 billions of petroleum that have affected the local population since the 1960s (8). Another organization in Massachusetts, the Worcester Roots Project, partnered with their city’s lead abatement program to conduct soil testing and clean up lead contaminated sites (ie potential garden spaces) using low-level bioremediation techniques (5). Despite the initial obstacles of their respective locations, these organizations have found innovative ways to curtail the practice’s most expensive costs and empower an informed citizenry to tackle environmental contamination within their communities.

Even though bioremediation research is still in its budding stage, it sheds insight on our never-ending war against environmental pollution. While our technological advances have paved way for our continued coexistence with the environment, perhaps some of our most effective allies lie in the very processes that sustained life millions of years ago.


References

(1) “Bioremediation.” Pollution Issues, 2014, www.pollutionissues.com/A-Bo/Bioremediation.html.

(2) Cheprasov, Artem Cheprasov. “History of Bioremediation.” Study.com, Study.com, study.com/academy/lesson/history-of-bioremediation.html.

(3) “A Citizen’s Guide to Bioremediation.” United States Environmental Protection Agency, Sept. 2012.

(4) “History.” BIOREMEDIATION, bioremediation2.weebly.com/history.html.

(5) “Home – Worcester Roots.” Worcester Roots | Sprouting up Cooperatively Owned and Green Initiatives for Social and Environmental Justice., 2001, www.worcesterroots.org/.

(6) Kellogg, Scott. “Why Bioremediation Is Scarce in Urban Gardens .” Utne, Ogden Publications, Inc, July 2013, www.utne.com/environment/bioremediation-ze0z1307zsau.

(7) KELLOGG, S. (2016). Community based bioremediation: grassroots responses to urban soil contamination, Revista Teknokultura Vol. 13(2), 491-510.  

(8) Maltz, Mia. “Home – Amazon Mycorenewal Project.” CoRenewal, CoRenewal, 2016, www.amazonmycorenewal.org/.

(9) Mastin, Brian, et al. “Bioremediation’s Integral Role in Ecosystem Restoration and Rehabilitation.” National Conference on Ecosystem Restoration, 5 Aug. 2011.

(10) Mouna Mahjoubi, Simone Cappello, Yasmine Souissi, Atef Jaouani and Ameur Cherif (February 7th 2018). Microbial Bioremediation of Petroleum Hydrocarbon– Contaminated Marine Environments, Recent Insights in Petroleum Science and Engineering Mansoor Zoveidavianpoor, IntechOpen, DOI: 10.5772/intechopen.72207. Available from: https://www.intechopen.com/books/recent-insights-in-petroleum-science-and-engineering/microbial-bioremediation-of-petroleum-hydrocarbon-contaminated-marine-environments

(11) ex situ – ‘off site’

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