Bread of Black Gold: Mycoremediation in the Amazon

^{(Illustration: Nicholas Toll)}

Between 1964 and 1992, Texaco, now part of Chevron, spilled 18.5 million gallons of oil in the Ecuadorian Amazon, inspiring Oxfam to dub it “The Environmental Crime of the Century." By way of comparison, the Exxon Valdez oil spill off the Alaskan coast in 1989 belched 11 million gallons into the Pacific Ocean. The spills took place over many decades and throughout the country’s eastern Amazon region, known as the Oriente, leaving an estimated 600 swimming pool-sized, open, unlined waste pits across an area the size of Rhode Island. Birth defects, along with cancer and leukemia rates—especially among children (1)— are extremely high in local communities. Community organizations, led by the Frente de Defensa de la Amazonia (Amazon Defense Front), have been engaged in a lawsuit against Chevron-Texaco since 2003, demanding billions of dollars to indemnize victims and repair the environment.

Texaco considered the basic oil-industry environmental practices, standard in the United States, prohibitively expensive in Ecuador. Texaco claims that they stayed within the law. But it is clear that they neglected safeguards, leading to unprecedented pollution in the heart of the most biodiverse region on the planet. The areas contaminated with oil are largely land-bound, meaning that there are few helpful natural processes, such as ocean currents or strong winds, to help dissipate the slicks. These processes played a key role in the recovery of the ecosystem after the Exxon Valdez spill, working alongside abundant aquatic bacterial populations that were instrumental in biodegrading the oil. Without such natural boons, vast pools of oil have persisted for decades in the Ecuadorian Amazon. And it is likely that the contamination will remain for much longer unless we begin looking to the fungal kingdom for a solution.

I am the Research Coordinator of the Amazon Mycorenewal Project (AMP), an international effort to apply recent advances in mycology that have expanded our understanding of the ability of certain mushrooms to breakdown toxic, organic compounds into fungal biomass—cleaning up oil pollution. A team of scientists and environmental advocates has been in Lago Agrio, Ecuador for the last several months testing a new, fungi-centered method for cleaning up these contaminated sites. The process we are testing, called mycoremediation, was developed by Washington mycologist Paul Stamets. The technique takes advantage of mushrooms' networked, thread-like, vegetative stage, called mycelium. Mycoremediation technology has major potential to rehabilitate habitat degraded and contaminated by petroleum waste.

While mycologists have been tinkering with fungal mycoremediation for more than a decade, the application of this technology has only recently been feasible. In a landmark study conducted at the Washington State Department of Transportation (WSDOT) maintenance yard in Bellingham, Stamets demonstrated oyster mushroom’s ability to breakdown crude oil in a non-laboratory scenario. The WSDOT maintenance yard had accumulated a large amount of oil-contaminated soil, so the WSDOT invited several remediation contractors to test methods for cleaning up the oil waste. Team Stamets hit a home run when they were able to remove “over 97 percent of the toxic and recalcitrant polycyclic aromatic hydrocarbons (PAHs) and more than 80 percent of the alkanes”(2)  in five weeks (3).

Image 1: This waste pit is 3 meters deep and completely unlined only 100 meters from a main road.

An Uncommon Meal

Many people forget, or perhaps never learned, that fungi are one of nature’s five kingdoms, and are neither plant nor animal. Modern science, in a sense, classifies life-forms by how they make energy. Plants produce energy through the process of photosynthesis, capturing sunlight and transforming it into glucose—a sugary form of energy. Animals, in contrast, create energy through eating the sun-originated glucose made by plants or by eating animals who eat plants. Fungi, nature’s decomposers, eat by exuding compounds like acids and enzymes that change the environment around them into something which is an edible substance.

Many mushrooms use these compounds to digest wood, which has two main structural components: cellulose and lignin. While animals and plants are unable to digest these substances, a class of fungi known as white-rotters has proved to be the only organism that has demonstrated the ability to eat lignin. Interestingly, the extracellular lignin-digesting enzymes produced by white-rotting fungi, such as oyster mushrooms, also enable them to breakdown crude petroleum.

The Amazon Mycorenewal Project’s strategy seems simple enough: apply a strain of oyster mushroom mycelium that has been laboratory acclimated to actually like eating oil to areas where there are large quantities of oil that need to be removed. That said, no mushroom, however dynamic, can live on petroleum alone. To seed a contaminated site, a mushroom starter called spawn and a fairly large amount of suitable mushroom food such as wood chips or sawdust are required. Since most contaminated sites that are common to the Amazon are usually large, liquid pits, a thorough mixing of sawdust and oil is ideal for mushroom growth and oxygenation.

Oyster mushrooms happen to be among nature’s most aggressive fungal species. They are able to metabolize a wide variety of food sources, from wood, to coffee grounds, to oil. Thus there is some choice in the types of substances that can be used to supplement the diet of fungi used in mycoremediation. Because of the large volume of organic material required, rural industry waste products of the Oreinte represent an easy and economical source. Presently, we are using sawdust and wooden dowels from a broomstick factory in Lago Agrio. However, we are also trying other local industry waste substrates from local industry like sugar cane husks, coconut fiber and coffee plantation debris.

Once we have mastered a solid, low-tech method, AMP will begin teaching the technique to community members. We are working with grassroots organizations that are already working on oil issues in the Amazon, like Frente de Denfensa de la Amazonia. Our primary goal is to make a tangible, beneficial impact on land afflicted by hazardous petroleum waste by developing a low-cost, effective and accessible mycoremediation process tailored to the Amazonian ecology. Keeping this goal in mind, the AMP team includes an Ecuadorian mycologist who has already spent four years teaching rural communities in the Oreinte how to grow edible mushrooms for food security and income generation. Following a similar model, we will reach out to communities, providing workshops and technical support that will enable this process’s rapid adoption

Image 2: Healthy mushrooms sprouting from highly contaminated soil

Forest Alchemy: Ubiquitous Mushrooms, Living Soil

Soil is alive. It is chock-full of critters large and small. Every cubic meter of soil contains loads of bacteria, fungi, spiders, mites, beetles, nematodes, plants, small mammals and reptiles vying for carbon and nutrients among the rich debris of dead plant and animal matter, clay, sand and silt. Since fungi are able to eat things that the rest of the usual suspects can’t, they proliferate. Other organisms are often best served by letting fungi do their work and then either directly feeding on the mushrooms or eating their chemically altered leftovers. In this way the fungi play a key role in the ecosystem as tiny alchemists, turning detritus into something useful. Mushrooms convert inaccessible cellulose and lignin into simpler sugars and elementary nutrients that can be eaten by other creatures.

At the AMP, we are taking advantage of fungi’s natural tendency to turn death and waste into fertile soil and available nutrients. We are designing our project to give our acclimated oyster mushrooms a leg up by taking advantage of the ecological desert created by the petroleum contamination. The areas are toxic by definition since no other organism really likes to munch on oil. Therefore, we would expect a life form specifically trained (not, to be clear, genetically engineered) to enjoy such a meal would have a distinct advantage in such an environment and thrive.

The oyster mushroom mycelium has performed well metabolizing petroleum in the Petri dish. But the Amazon is not a sterile and orderly laboratory. Will the mushrooms become food for insects or out-competed by other weedy fungi? We don’t know for sure. Creating an ecological advantage for the mushrooms will require more than just sowing them in oil. While oyster mushroom’s oil-digesting capabilities may be a part of the new technology of mycoremediation, the specific process of its application to an affected area is what will ultimately allow it to succeed with as little input and maintenance as possible. This is important because the Ecuadorian Amazon’s contaminated areas are so vast and heterogeneous that our techniques will likely have to be site-specific. In most cases it will be necessary to occasionally add more fungal material to maintain the dominance of the acclimated oysters in the affected site—as the fungi do their work, the area becomes more hospitable to potential competitors that were previously excluded by the contamination.

The current state of this project is encouraging. Mycelium is actively spreading over and into the highest contamination concentrations tested, with healthy mushrooms fruiting directly from highly toxic soil. By toxic, we mean petroleum collected from a 30-year old waste pit that has managed to suppress plant growth in the middle of the Amazon Rainforest. This same thick, stinky oil seems to present no major obstacle to oyster mushroom growth, with a little human help. The next step, slated for 2009, is to apply this technology in the field by attempting to clean up a real waste pit.

Mycelium threads through every inch of fertile soil on the planet. In fact, aside from plant biomass in forest ecosystems, fungal biomass outweighs any other living component by an average of 50 to 1. Fungi’s ability to spread over large areas as a single organism—crucial for success in cleaning up vast waste pits—is unparalleled: in Eastern Oregon there is a single fungal individual that extends its network over 2,200 acres. The presence of fungal networks holds water in the soil and prevents erosion and desertification. While molds and rot are typically viewed with disgust, they are the indispensable components of nutrient cycles that literally enable life as we see it to exist on this planet. Although there are too many pathogenic fungi to even begin to name here, they are not the only face of the fungal kingdom. In the Amazon and the compost heap in your garden, fungi are converting waste and toxicity into a rich store of things to come.

Trained as a botanist, Brian Pace first become enamored with the fungal world in the temperate rainforests of the Pacific Northwest. His interests include permaculture, natural history and Filipino martial arts. Brian lives and works in Ecuador. For more information on the fight for justice against Texaco, check out www.texacotoxico.org or www.amazonwatch.org

(1) Anna-Karin Hurtig and Miguel San Sebastián, Incidence of Childhood Leukemia and Oil Exploitation in the Amazon Basin of Ecuador, International Journal of Occupational and Environmental Health, vol. 10/no. 3, July/Sep 2003 

(2) Paul Stamets, The Earth's Natural Internet, Whole Earth Catalog, 1999

(3) Alkanes are three carbon compounds, while PAHs are airborne, poisonous carbon rings common to petroleum waste (they give crude oil its characteristic odor). Both substances are quite toxic and are difficult to degrade because of their strong covalent bonds.